Initial Contribution

11 files changed, 2513 insertions, 0 deletions

diff --git a/debuggerd/Android.mk b/debuggerd/Android.mk
new file mode 100644
index 00000000..03046bd5
--- /dev/null
+++ b/debuggerd/Android.mk
@@ -0,0 +1,22 @@
+# Copyright 2005 The Android Open Source Project
+
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= debuggerd.c getevent.c unwind-arm.c pr-support.c utility.c
+LOCAL_CFLAGS := -Wall
+LOCAL_MODULE := debuggerd
+
+LOCAL_STATIC_LIBRARIES := libcutils libc
+
+include $(BUILD_EXECUTABLE)
+
+include $(CLEAR_VARS)
+LOCAL_SRC_FILES := crasher.c 
+LOCAL_SRC_FILES += crashglue.S
+LOCAL_MODULE := crasher 
+LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
+LOCAL_MODULE_TAGS := eng
+#LOCAL_FORCE_STATIC_EXECUTABLE := true
+LOCAL_SHARED_LIBRARIES := libcutils libc
+include $(BUILD_EXECUTABLE)
diff --git a/debuggerd/MODULE_LICENSE_APACHE2 b/debuggerd/MODULE_LICENSE_APACHE2
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/debuggerd/MODULE_LICENSE_APACHE2
diff --git a/debuggerd/NOTICE b/debuggerd/NOTICE
new file mode 100644
index 00000000..c5b1efa7
--- /dev/null
+++ b/debuggerd/NOTICE
@@ -0,0 +1,190 @@
+
+   Copyright (c) 2005-2008, The Android Open Source Project
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
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+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
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+
+      "Work" shall mean the work of authorship, whether in Source or
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+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
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+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
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+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
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+      Work and such Derivative Works in Source or Object form.
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+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
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+      (d) If the Work includes a "NOTICE" text file as part of its
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+          of the NOTICE file are for informational purposes only and
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+          notices within Derivative Works that You distribute, alongside
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+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
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+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
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+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
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+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
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+      negligent acts) or agreed to in writing, shall any Contributor be
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+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
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+   END OF TERMS AND CONDITIONS
+
diff --git a/debuggerd/crasher.c b/debuggerd/crasher.c
new file mode 100644
index 00000000..f4a5a62b
--- /dev/null
+++ b/debuggerd/crasher.c
@@ -0,0 +1,105 @@
+
+//#include <cutils/misc.h>
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sched.h>
+#include <errno.h>
+
+#include <signal.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <sys/socket.h>
+
+#include <pthread.h>
+
+#include <cutils/sockets.h>
+
+void crash1(void);
+void crashnostack(void);
+
+static void debuggerd_connect()
+{
+    char tmp[1];
+    int s;
+    sprintf(tmp, "%d", gettid());
+    s = socket_local_client("android:debuggerd",
+            ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM);    
+    if(s >= 0) {
+        read(s, tmp, 1);
+        close(s);
+    }
+}
+
+void test_call1()
+{
+    *((int*) 32) = 1;
+}
+
+void *test_thread(void *x)
+{
+    printf("crasher: thread pid=%d tid=%d\n", getpid(), gettid());
+
+    sleep(1);
+    test_call1();
+    printf("goodbye\n");
+
+    return 0;
+}
+
+void *noisy(void *x)
+{
+    char c = (unsigned) x;
+    for(;;) {
+        usleep(250*1000);
+        write(2, &c, 1);
+        if(c == 'C') *((unsigned*) 0) = 42;
+    }
+    return 0;
+}
+
+int ctest()
+{
+    pthread_t thr;
+    pthread_attr_t attr;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+    pthread_create(&thr, &attr, noisy, (void*) 'A');
+    pthread_create(&thr, &attr, noisy, (void*) 'B');
+    pthread_create(&thr, &attr, noisy, (void*) 'C');
+    for(;;) ;
+    return 0;
+}
+
+int main(int argc, char **argv)
+{
+    pthread_t thr;
+    pthread_attr_t attr;
+
+    fprintf(stderr,"crasher: " __TIME__ "!@\n");
+    fprintf(stderr,"crasher: init pid=%d tid=%d\n", getpid(), gettid());
+
+    if(argc > 1) {
+        if(!strcmp(argv[1],"nostack")) crashnostack();
+        if(!strcmp(argv[1],"ctest")) return ctest();
+        if(!strcmp(argv[1],"exit")) exit(1);
+        if(!strcmp(argv[1],"abort")) maybeabort();
+        
+        pthread_attr_init(&attr);
+        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+        pthread_create(&thr, &attr, test_thread, 0);
+        while(1) sleep(1);
+    } else {
+        crash1();
+//        *((int*) 0) = 42;
+    }
+    
+    return 0;
+}
+
+void maybeabort()
+{
+    if(time(0) != 42) abort();
+}
diff --git a/debuggerd/crashglue.S b/debuggerd/crashglue.S
new file mode 100644
index 00000000..888951b9
--- /dev/null
+++ b/debuggerd/crashglue.S
@@ -0,0 +1,28 @@
+.globl crash1
+.globl crashnostack
+		
+crash1:
+	ldr r0, =0xa5a50000
+	ldr r1, =0xa5a50001
+	ldr r2, =0xa5a50002
+	ldr r3, =0xa5a50003
+	ldr r4, =0xa5a50004
+	ldr r5, =0xa5a50005
+	ldr r6, =0xa5a50006
+	ldr r7, =0xa5a50007
+	ldr r8, =0xa5a50008
+	ldr r9, =0xa5a50009
+	ldr r10, =0xa5a50010
+	ldr r11, =0xa5a50011
+	ldr r12, =0xa5a50012
+
+	mov lr, #0
+	ldr lr, [lr]
+	b .
+
+
+crashnostack:
+	mov sp, #0
+	mov r0, #0
+	ldr r0, [r0]
+	b .
\ No newline at end of file
diff --git a/debuggerd/debuggerd.c b/debuggerd/debuggerd.c
new file mode 100644
index 00000000..9394e1ca
--- /dev/null
+++ b/debuggerd/debuggerd.c
@@ -0,0 +1,852 @@
+/* system/debuggerd/debuggerd.c
+**
+** Copyright 2006, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <pthread.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <dirent.h>
+
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <sys/exec_elf.h>
+#include <sys/stat.h>
+
+#include <cutils/sockets.h>
+#include <cutils/logd.h>
+#include <cutils/sockets.h>
+#include <cutils/properties.h>
+
+#include <linux/input.h>
+
+#include <private/android_filesystem_config.h>
+
+#include "utility.h"
+
+/* Main entry point to get the backtrace from the crashing process */
+extern int unwind_backtrace_with_ptrace(int tfd, pid_t pid, mapinfo *map,
+                                        unsigned int sp_list[],
+                                        int *frame0_pc_sane,
+                                        bool at_fault);
+
+static char **process_name_ptr;
+
+static int logsocket = -1;
+
+#define ANDROID_LOG_INFO 4
+
+/* Log information onto the tombstone */
+void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...)
+{
+    char buf[128];
+    
+    va_list ap;
+    va_start(ap, fmt);
+
+    if (tfd >= 0) {
+        int len;
+        vsnprintf(buf, sizeof(buf), fmt, ap);
+        len = strlen(buf);
+        if(tfd >= 0) write(tfd, buf, len);
+    }
+
+    if (!in_tombstone_only)
+        __android_log_vprint(ANDROID_LOG_INFO, "DEBUG", fmt, ap);
+}
+
+#define LOG(fmt...) _LOG(-1, 0, fmt)
+#if 0
+#define XLOG(fmt...) _LOG(-1, 0, fmt)
+#else
+#define XLOG(fmt...) do {} while(0)
+#endif
+
+// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419   /system/lib/libcomposer.so
+// 012345678901234567890123456789012345678901234567890123456789
+// 0         1         2         3         4         5
+
+mapinfo *parse_maps_line(char *line)
+{
+    mapinfo *mi;
+    int len = strlen(line);
+
+    if(len < 1) return 0;
+    line[--len] = 0;
+    
+    if(len < 50) return 0;
+    if(line[20] != 'x') return 0;
+
+    mi = malloc(sizeof(mapinfo) + (len - 47));
+    if(mi == 0) return 0;
+    
+    mi->start = strtoul(line, 0, 16);
+    mi->end = strtoul(line + 9, 0, 16);
+    /* To be filled in parse_exidx_info if the mapped section starts with 
+     * elf_header
+     */
+    mi->exidx_start = mi->exidx_end = 0;
+    mi->next = 0;
+    strcpy(mi->name, line + 49);
+
+    return mi;
+}
+
+void dump_build_info(int tfd)
+{
+    char fingerprint[PROPERTY_VALUE_MAX];
+
+    property_get("ro.build.fingerprint", fingerprint, "unknown");
+
+    _LOG(tfd, false, "Build fingerprint: '%s'\n", fingerprint);
+}
+
+
+void dump_stack_and_code(int tfd, int pid, mapinfo *map, 
+                         int unwind_depth, unsigned int sp_list[],
+                         int frame0_pc_sane, bool at_fault)
+{
+    unsigned int sp, pc, p, end, data;
+    struct pt_regs r;
+    int sp_depth;
+    bool only_in_tombstone = !at_fault;
+
+    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) return;
+    sp = r.ARM_sp;
+    pc = r.ARM_pc;
+
+    /* Died because calling the weeds - dump
+     * the code around the PC in the next frame instead.
+     */
+    if (frame0_pc_sane == 0) {
+        pc = r.ARM_lr;
+    }
+
+    _LOG(tfd, true, "code%s:\n", frame0_pc_sane ? "" : " (around frame #01)");
+
+    end = p = pc & ~3;
+    p -= 16;
+
+    /* Dump the code as:
+     *  PC         contents
+     *  00008d34   fffffcd0 4c0eb530 b0934a0e 1c05447c
+     *  00008d44   f7ff18a0 490ced94 68035860 d0012b00
+     */
+    while (p <= end) {
+        int i;
+
+        _LOG(tfd, true, " %08x  ", p);
+        for (i = 0; i < 4; i++) {
+            data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);
+            _LOG(tfd, true, " %08x", data);
+            p += 4;
+        }
+        _LOG(tfd, true, "\n", p);
+    }
+
+    p = sp - 64;
+    p &= ~3;
+    if (unwind_depth != 0) {
+        if (unwind_depth < STACK_CONTENT_DEPTH) {
+            end = sp_list[unwind_depth-1];
+        }
+        else {
+            end = sp_list[STACK_CONTENT_DEPTH-1];
+        }
+    }
+    else {
+        end = sp | 0x000000ff;
+        end += 0xff;
+    }
+
+    _LOG(tfd, only_in_tombstone, "stack:\n");
+
+    /* If the crash is due to PC == 0, there will be two frames that
+     * have identical SP value.
+     */
+    if (sp_list[0] == sp_list[1]) {
+        sp_depth = 1;
+    }
+    else {
+        sp_depth = 0;
+    }
+
+    while (p <= end) {
+         char *prompt; 
+         char level[16];
+         data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);
+         if (p == sp_list[sp_depth]) {
+             sprintf(level, "#%02d", sp_depth++);
+             prompt = level;
+         }
+         else {
+             prompt = "   ";
+         }
+         
+         /* Print the stack content in the log for the first 3 frames. For the
+          * rest only print them in the tombstone file.
+          */
+         _LOG(tfd, (sp_depth > 2) || only_in_tombstone, 
+              "%s %08x  %08x  %s\n", prompt, p, data, 
+              map_to_name(map, data, ""));
+         p += 4;
+    }
+    /* print another 64-byte of stack data after the last frame */
+
+    end = p+64;
+    while (p <= end) {
+         data = ptrace(PTRACE_PEEKTEXT, pid, (void*)p, NULL);
+         _LOG(tfd, (sp_depth > 2) || only_in_tombstone, 
+              "    %08x  %08x  %s\n", p, data, 
+              map_to_name(map, data, ""));
+         p += 4;
+    }
+}
+
+void dump_pc_and_lr(int tfd, int pid, mapinfo *map, int unwound_level, 
+                    bool at_fault)
+{
+    struct pt_regs r;
+
+    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) {
+        _LOG(tfd, !at_fault, "tid %d not responding!\n", pid);
+        return;
+    }
+
+    if (unwound_level == 0) {
+        _LOG(tfd, !at_fault, "         #%02d  pc %08x  %s\n", 0, r.ARM_pc,
+             map_to_name(map, r.ARM_pc, "<unknown>"));
+    }
+    _LOG(tfd, !at_fault, "         #%02d  lr %08x  %s\n", 1, r.ARM_lr,
+            map_to_name(map, r.ARM_lr, "<unknown>"));
+}
+
+void dump_registers(int tfd, int pid, bool at_fault) 
+{
+    struct pt_regs r;
+    bool only_in_tombstone = !at_fault;
+
+    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) {
+        _LOG(tfd, only_in_tombstone, 
+             "cannot get registers: %s\n", strerror(errno));
+        return;
+    }
+    
+    _LOG(tfd, only_in_tombstone, " r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
+         r.ARM_r0, r.ARM_r1, r.ARM_r2, r.ARM_r3);
+    _LOG(tfd, only_in_tombstone, " r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
+         r.ARM_r4, r.ARM_r5, r.ARM_r6, r.ARM_r7);
+    _LOG(tfd, only_in_tombstone, " r8 %08x  r9 %08x  10 %08x  fp %08x\n",
+         r.ARM_r8, r.ARM_r9, r.ARM_r10, r.ARM_fp);
+    _LOG(tfd, only_in_tombstone, 
+         " ip %08x  sp %08x  lr %08x  pc %08x  cpsr %08x\n",
+         r.ARM_ip, r.ARM_sp, r.ARM_lr, r.ARM_pc, r.ARM_cpsr);  
+}
+
+const char *get_signame(int sig)
+{
+    switch(sig) {
+    case SIGILL:     return "SIGILL";
+    case SIGABRT:    return "SIGABRT";
+    case SIGBUS:     return "SIGBUS";
+    case SIGFPE:     return "SIGFPE";
+    case SIGSEGV:    return "SIGSEGV";
+    case SIGSTKFLT:  return "SIGSTKFLT";
+    default:         return "?";
+    }
+}
+
+void dump_fault_addr(int tfd, int pid, int sig)
+{
+    siginfo_t si;
+    
+    memset(&si, 0, sizeof(si));
+    if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){
+        _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno));
+    } else {
+        _LOG(tfd, false, "signal %d (%s), fault addr %08x\n",
+            sig, get_signame(sig), si.si_addr);
+    }
+}
+
+void dump_crash_banner(int tfd, unsigned pid, unsigned tid, int sig)
+{
+    char data[1024];
+    char *x = 0;
+    FILE *fp;
+    
+    sprintf(data, "/proc/%d/cmdline", pid);
+    fp = fopen(data, "r");
+    if(fp) {
+        x = fgets(data, 1024, fp);
+        fclose(fp);
+    }
+    
+    _LOG(tfd, false,
+         "*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***\n");
+    dump_build_info(tfd);
+    _LOG(tfd, false, "pid: %d, tid: %d  >>> %s <<<\n",
+         pid, tid, x ? x : "UNKNOWN");
+    
+    if(sig) dump_fault_addr(tfd, tid, sig);
+}
+
+static void parse_exidx_info(mapinfo *milist, pid_t pid)
+{
+    mapinfo *mi;
+    for (mi = milist; mi != NULL; mi = mi->next) {
+        Elf32_Ehdr ehdr;
+
+        memset(&ehdr, 0, sizeof(Elf32_Ehdr));
+        /* Read in sizeof(Elf32_Ehdr) worth of data from the beginning of 
+         * mapped section.
+         */
+        get_remote_struct(pid, (void *) (mi->start), &ehdr, 
+                          sizeof(Elf32_Ehdr));
+        /* Check if it has the matching magic words */
+        if (IS_ELF(ehdr)) {
+            Elf32_Phdr phdr;
+            Elf32_Phdr *ptr;
+            int i;
+
+            ptr = (Elf32_Phdr *) (mi->start + ehdr.e_phoff);
+            for (i = 0; i < ehdr.e_phnum; i++) {
+                /* Parse the program header */
+                get_remote_struct(pid, (void *) ptr+i, &phdr, 
+                                  sizeof(Elf32_Phdr));
+                /* Found a EXIDX segment? */
+                if (phdr.p_type == PT_ARM_EXIDX) {
+                    mi->exidx_start = mi->start + phdr.p_offset;
+                    mi->exidx_end = mi->exidx_start + phdr.p_filesz;
+                    break;
+                }
+            }
+        }
+    }
+}
+
+void dump_crash_report(int tfd, unsigned pid, unsigned tid, bool at_fault)
+{
+    char data[1024];
+    FILE *fp;
+    mapinfo *milist = 0;
+    unsigned int sp_list[STACK_CONTENT_DEPTH];
+    int stack_depth;
+    int frame0_pc_sane = 1;
+    
+    if (!at_fault) {
+        _LOG(tfd, true,
+         "--- --- --- --- --- --- --- --- --- --- --- --- --- --- --- ---\n");
+        _LOG(tfd, true, "pid: %d, tid: %d\n", pid, tid);
+    }
+
+    dump_registers(tfd, tid, at_fault);
+    
+    /* Clear stack pointer records */
+    memset(sp_list, 0, sizeof(sp_list));
+
+    sprintf(data, "/proc/%d/maps", pid);
+    fp = fopen(data, "r");
+    if(fp) {
+        while(fgets(data, 1024, fp)) {
+            mapinfo *mi = parse_maps_line(data);
+            if(mi) {
+                mi->next = milist;
+                milist = mi;
+            }
+        }
+        fclose(fp);
+    }
+
+    parse_exidx_info(milist, tid);
+
+    /* If stack unwinder fails, use the default solution to dump the stack
+     * content.
+     */
+    stack_depth = unwind_backtrace_with_ptrace(tfd, tid, milist, sp_list,
+                                               &frame0_pc_sane, at_fault);
+
+    /* The stack unwinder should at least unwind two levels of stack. If less
+     * level is seen we make sure at lease pc and lr are dumped.
+     */
+    if (stack_depth < 2) {
+        dump_pc_and_lr(tfd, tid, milist, stack_depth, at_fault);
+    }
+
+    dump_stack_and_code(tfd, tid, milist, stack_depth, sp_list, frame0_pc_sane,
+                        at_fault);
+
+    while(milist) {
+        mapinfo *next = milist->next;
+        free(milist);
+        milist = next;
+    }
+}
+
+/* FIXME: unused: use it or lose it*/
+#if 0
+static
+void start_gdbserver_vs(int pid, int port)
+{
+    pid_t p;
+    char *args[5];
+    char commspec[16];
+    char pidspec[16];
+    
+    p = fork();
+    if(p < 0) {
+        LOG("could not fork()\n");
+        return;
+    }
+
+    if(p == 0) {
+        sprintf(commspec, ":%d", port);
+        sprintf(pidspec, "%d", pid);
+        args[0] = "/system/bin/gdbserver";
+        args[1] = commspec;
+        args[2] = "--attach";
+        args[3] = pidspec;
+        args[4] = 0;
+        exit(execv(args[0], args));
+    } else {
+        LOG("gdbserver pid=%d port=%d targetpid=%d\n",
+            p, port, pid);
+
+        sleep(5);
+    }
+}
+#endif
+
+#define MAX_TOMBSTONES	10
+
+#define typecheck(x,y) {    \
+    typeof(x) __dummy1;     \
+    typeof(y) __dummy2;     \
+    (void)(&__dummy1 == &__dummy2); }
+
+#define TOMBSTONE_DIR	"/data/tombstones"
+
+/*
+ * find_and_open_tombstone - find an available tombstone slot, if any, of the
+ * form tombstone_XX where XX is 00 to MAX_TOMBSTONES-1, inclusive. If no
+ * file is available, we reuse the least-recently-modified file.
+ */
+static int find_and_open_tombstone(void)
+{
+    unsigned long mtime = ULONG_MAX;
+    struct stat sb;
+    char path[128];
+    int fd, i, oldest = 0;
+
+    /*
+     * XXX: Our stat.st_mtime isn't time_t. If it changes, as it probably ought
+     * to, our logic breaks. This check will generate a warning if that happens.
+     */
+    typecheck(mtime, sb.st_mtime);
+
+    /*
+     * In a single wolf-like pass, find an available slot and, in case none
+     * exist, find and record the least-recently-modified file.
+     */
+    for (i = 0; i < MAX_TOMBSTONES; i++) {
+        snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", i);
+
+        if (!stat(path, &sb)) {
+            if (sb.st_mtime < mtime) {
+                oldest = i;
+                mtime = sb.st_mtime;
+            }
+            continue;
+        }
+        if (errno != ENOENT)
+            continue;
+
+        fd = open(path, O_CREAT | O_EXCL | O_WRONLY, 0600);
+        if (fd < 0)
+            continue;	/* raced ? */
+
+        fchown(fd, AID_SYSTEM, AID_SYSTEM);
+        return fd;
+    }
+
+    /* we didn't find an available file, so we clobber the oldest one */
+    snprintf(path, sizeof(path), TOMBSTONE_DIR"/tombstone_%02d", oldest);
+    fd = open(path, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+    fchown(fd, AID_SYSTEM, AID_SYSTEM);
+
+    return fd;
+}
+
+/* Return true if some thread is not detached cleanly */
+static bool dump_sibling_thread_report(int tfd, unsigned pid, unsigned tid)
+{
+    char task_path[1024];
+
+    sprintf(task_path, "/proc/%d/task", pid);
+    DIR *d;
+    struct dirent *de;
+    int need_cleanup = 0;
+
+    d = opendir(task_path);
+    /* Bail early if cannot open the task directory */
+    if (d == NULL) {
+        XLOG("Cannot open /proc/%d/task\n", pid);
+        return false;
+    }
+    while ((de = readdir(d)) != NULL) {
+        unsigned new_tid;
+        /* Ignore "." and ".." */
+        if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) 
+            continue;
+        new_tid = atoi(de->d_name);
+        /* The main thread at fault has been handled individually */
+        if (new_tid == tid)
+            continue;
+
+        /* Skip this thread if cannot ptrace it */
+        if (ptrace(PTRACE_ATTACH, new_tid, 0, 0) < 0)
+            continue;
+
+        dump_crash_report(tfd, pid, new_tid, false);
+        need_cleanup |= ptrace(PTRACE_DETACH, new_tid, 0, 0);
+    }
+    closedir(d);
+    return need_cleanup != 0;
+}
+
+/* Return true if some thread is not detached cleanly */
+static bool engrave_tombstone(unsigned pid, unsigned tid, int debug_uid, 
+                              int signal)
+{
+    int fd;
+    bool need_cleanup = false;
+
+    mkdir(TOMBSTONE_DIR, 0755);
+    chown(TOMBSTONE_DIR, AID_SYSTEM, AID_SYSTEM);
+
+    fd = find_and_open_tombstone();
+    if (fd < 0)
+        return need_cleanup;
+
+    dump_crash_banner(fd, pid, tid, signal);
+    dump_crash_report(fd, pid, tid, true);
+    /* 
+     * If the user has requested to attach gdb, don't collect the per-thread
+     * information as it increases the chance to lose track of the process.
+     */
+    if ((signed)pid > debug_uid) {
+        need_cleanup = dump_sibling_thread_report(fd, pid, tid);
+    }
+
+    close(fd);
+    return need_cleanup;
+}
+
+static int
+write_string(const char* file, const char* string)
+{
+    int len;
+    int fd;
+    ssize_t amt;
+    fd = open(file, O_RDWR);
+    len = strlen(string);
+    if (fd < 0)
+        return -errno;
+    amt = write(fd, string, len);
+    close(fd);
+    return amt >= 0 ? 0 : -errno;
+}
+
+static
+void init_debug_led(void)
+{
+    // trout leds
+    write_string("/sys/class/leds/red/brightness", "0");
+    write_string("/sys/class/leds/green/brightness", "0");
+    write_string("/sys/class/leds/blue/brightness", "0");
+    write_string("/sys/class/leds/red/device/blink", "0");
+    // sardine leds
+    write_string("/sys/class/leds/left/cadence", "0,0");
+}
+
+static
+void enable_debug_led(void)
+{
+    // trout leds
+    write_string("/sys/class/leds/red/brightness", "255");
+    // sardine leds
+    write_string("/sys/class/leds/left/cadence", "1,0");
+}
+
+static
+void disable_debug_led(void)
+{
+    // trout leds
+    write_string("/sys/class/leds/red/brightness", "0");
+    // sardine leds
+    write_string("/sys/class/leds/left/cadence", "0,0");
+}
+
+extern int init_getevent();
+extern void uninit_getevent();
+extern int get_event(struct input_event* event, int timeout);
+
+static void wait_for_user_action(unsigned tid, struct ucred* cr)
+{
+    (void)tid;
+    /* First log a helpful message */
+    LOG(    "********************************************************\n"
+            "* process %d crashed. debuggerd waiting for gdbserver   \n"
+            "*                                                       \n"
+            "*     adb shell gdbserver :port --attach %d &           \n"
+            "*                                                       \n"
+            "* and press the HOME key.                               \n"
+            "********************************************************\n",                
+            cr->pid, cr->pid);
+
+    /* wait for HOME key */
+    if (init_getevent() == 0) {
+        int ms = 1200 / 10;
+        int dit = 1;
+        int dah = 3*dit;
+        int _       = -dit;
+        int ___     = 3*_;
+        int _______ = 7*_;
+        const signed char codes[] = {
+           dit,_,dit,_,dit,___,dah,_,dah,_,dah,___,dit,_,dit,_,dit,_______
+        };
+        size_t s = 0;
+        struct input_event e;
+        int home = 0;
+        init_debug_led();
+        enable_debug_led();
+        do {
+            int timeout = abs((int)(codes[s])) * ms;
+            int res = get_event(&e, timeout);
+            if (res == 0) {
+                if (e.type==EV_KEY && e.code==KEY_HOME && e.value==0)
+                    home = 1;
+            } else if (res == 1) {
+                if (++s >= sizeof(codes)/sizeof(*codes))
+                    s = 0;
+                if (codes[s] > 0) {
+                    enable_debug_led();
+                } else {
+                    disable_debug_led();
+                }
+            }
+        } while (!home); 
+        uninit_getevent();
+    }
+
+    /* don't forget to turn debug led off */
+    disable_debug_led();
+    
+    /* close filedescriptor */
+    LOG("debuggerd resuming process %d", cr->pid);
+ }
+
+static void handle_crashing_process(int fd)
+{
+    char buf[64];
+    struct stat s;
+    unsigned tid;
+    struct ucred cr;
+    int n, len, status; 
+    int tid_attach_status = -1;
+    unsigned retry = 30;
+    bool need_cleanup = false;
+
+    char value[PROPERTY_VALUE_MAX];
+    property_get("debug.db.uid", value, "-1");
+    int debug_uid = atoi(value);
+    
+    XLOG("handle_crashing_process(%d)\n", fd);
+    
+    len = sizeof(cr);
+    n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len);
+    if(n != 0) {
+        LOG("cannot get credentials\n");
+        goto done;
+    }
+
+    XLOG("reading tid\n");    
+    fcntl(fd, F_SETFL, O_NONBLOCK);
+    while((n = read(fd, &tid, sizeof(unsigned))) != sizeof(unsigned)) {
+        if(errno == EINTR) continue;
+        if(errno == EWOULDBLOCK) {
+            if(retry-- > 0) {
+                usleep(100 * 1000);
+                continue;
+            }
+            LOG("timed out reading tid\n");
+            goto done;
+        }
+        LOG("read failure? %s\n", strerror(errno));
+        goto done;
+    }
+
+    sprintf(buf,"/proc/%d/task/%d", cr.pid, tid);
+    if(stat(buf, &s)) {
+        LOG("tid %d does not exist in pid %d. ignorning debug request\n",
+            tid, cr.pid);
+        close(fd);
+        return;
+    }
+    
+    XLOG("BOOM: pid=%d uid=%d gid=%d tid=%d\n", cr.pid, cr.uid, cr.gid, tid);
+
+    tid_attach_status = ptrace(PTRACE_ATTACH, tid, 0, 0);
+    if(tid_attach_status < 0) {
+        LOG("ptrace attach failed: %s\n", strerror(errno));
+        goto done;
+    }
+
+    close(fd);
+    fd = -1;
+
+    for(;;) {
+        n = waitpid(tid, &status, __WALL);
+        
+        if(n < 0) {
+            if(errno == EAGAIN) continue;
+            LOG("waitpid failed: %s\n", strerror(errno));
+            goto done;
+        }
+
+        XLOG("waitpid: n=%d status=%08x\n", n, status);
+
+        if(WIFSTOPPED(status)){
+            n = WSTOPSIG(status);
+            switch(n) {
+            case SIGSTOP:
+                XLOG("stopped -- continuing\n");
+                n = ptrace(PTRACE_CONT, tid, 0, 0);
+                if(n) {
+                    LOG("ptrace failed: %s\n", strerror(errno));
+                    goto done;
+                }
+                continue;
+                
+            case SIGILL:
+            case SIGABRT:
+            case SIGBUS:
+            case SIGFPE:
+            case SIGSEGV:
+            case SIGSTKFLT: {
+                XLOG("stopped -- fatal signal\n");
+                need_cleanup = engrave_tombstone(cr.pid, tid, debug_uid, n);
+                kill(tid, SIGSTOP);
+                goto done;
+            }
+
+            default:
+                XLOG("stopped -- unexpected signal\n");
+                goto done;
+            }
+        } else {
+            XLOG("unexpected waitpid response\n");
+            goto done;
+        }
+    }
+    
+done:
+    XLOG("detaching\n");
+    
+    /* stop the process so we can debug */
+    kill(cr.pid, SIGSTOP);
+
+    /* 
+     * If a thread has been attached by ptrace, make sure it is detached 
+     * successfully otherwise we will get a zombie.
+     */ 
+    if (tid_attach_status == 0) {
+        int detach_status;
+        /* detach so we can attach gdbserver */
+        detach_status = ptrace(PTRACE_DETACH, tid, 0, 0);
+        need_cleanup |= (detach_status != 0);
+    }
+
+    /*
+     * if debug.db.uid is set, its value indicates if we should wait
+     * for user action for the crashing process.
+     * in this case, we log a message and turn the debug LED on
+     * waiting for a gdb connection (for instance)
+     */
+
+    if ((signed)cr.uid <= debug_uid) {
+        wait_for_user_action(tid, &cr);
+    }
+
+    /* resume stopped process (so it can crash in peace) */
+    kill(cr.pid, SIGCONT);
+
+    if (need_cleanup) {
+        LOG("debuggerd committing suicide to free the zombie!\n");
+        kill(getpid(), SIGKILL);
+    }
+
+    if(fd != -1) close(fd);
+}
+
+int main(int argc, char **argv)
+{
+    int s;
+    struct sigaction act;
+    
+    process_name_ptr = argv;
+    
+    logsocket = socket_local_client("logd", 
+            ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_DGRAM);
+    if(logsocket < 0) {
+        logsocket = -1;
+    } else {
+        fcntl(logsocket, F_SETFD, FD_CLOEXEC);
+    }
+
+    act.sa_handler = SIG_DFL;
+    sigemptyset(&act.sa_mask);
+    sigaddset(&act.sa_mask,SIGCHLD);
+    act.sa_flags = SA_NOCLDWAIT;
+    sigaction(SIGCHLD, &act, 0);
+    
+    s = socket_local_server("android:debuggerd", 
+            ANDROID_SOCKET_NAMESPACE_ABSTRACT, SOCK_STREAM);
+    if(s < 0) return -1;
+    fcntl(s, F_SETFD, FD_CLOEXEC);
+
+    LOG("debuggerd: " __DATE__ " " __TIME__ "\n");
+    
+    for(;;) {
+        struct sockaddr addr;
+        socklen_t alen;
+        int fd;
+        
+        alen = sizeof(addr);
+        fd = accept(s, &addr, &alen);
+        if(fd < 0) continue;
+        
+        fcntl(fd, F_SETFD, FD_CLOEXEC);
+
+        handle_crashing_process(fd);
+    }
+    return 0;
+}
diff --git a/debuggerd/getevent.c b/debuggerd/getevent.c
new file mode 100644
index 00000000..ebd070c0
--- /dev/null
+++ b/debuggerd/getevent.c
@@ -0,0 +1,219 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/inotify.h>
+#include <sys/limits.h>
+#include <sys/poll.h>
+#include <linux/input.h>
+#include <errno.h>
+#include <cutils/log.h>
+
+static struct pollfd *ufds;
+static char **device_names;
+static int nfds;
+
+static int open_device(const char *device)
+{
+    int version;
+    int fd;
+    struct pollfd *new_ufds;
+    char **new_device_names;
+    char name[80];
+    char location[80];
+    char idstr[80];
+    struct input_id id;
+
+    fd = open(device, O_RDWR);
+    if(fd < 0) {
+        return -1;
+    }
+    
+    if(ioctl(fd, EVIOCGVERSION, &version)) {
+        return -1;
+    }
+    if(ioctl(fd, EVIOCGID, &id)) {
+        return -1;
+    }
+    name[sizeof(name) - 1] = '\0';
+    location[sizeof(location) - 1] = '\0';
+    idstr[sizeof(idstr) - 1] = '\0';
+    if(ioctl(fd, EVIOCGNAME(sizeof(name) - 1), &name) < 1) {
+        //fprintf(stderr, "could not get device name for %s, %s\n", device, strerror(errno));
+        name[0] = '\0';
+    }
+    if(ioctl(fd, EVIOCGPHYS(sizeof(location) - 1), &location) < 1) {
+        //fprintf(stderr, "could not get location for %s, %s\n", device, strerror(errno));
+        location[0] = '\0';
+    }
+    if(ioctl(fd, EVIOCGUNIQ(sizeof(idstr) - 1), &idstr) < 1) {
+        //fprintf(stderr, "could not get idstring for %s, %s\n", device, strerror(errno));
+        idstr[0] = '\0';
+    }
+
+    new_ufds = realloc(ufds, sizeof(ufds[0]) * (nfds + 1));
+    if(new_ufds == NULL) {
+        fprintf(stderr, "out of memory\n");
+        return -1;
+    }
+    ufds = new_ufds;
+    new_device_names = realloc(device_names, sizeof(device_names[0]) * (nfds + 1));
+    if(new_device_names == NULL) {
+        fprintf(stderr, "out of memory\n");
+        return -1;
+    }
+    device_names = new_device_names;
+    ufds[nfds].fd = fd;
+    ufds[nfds].events = POLLIN;
+    device_names[nfds] = strdup(device);
+    nfds++;
+
+    return 0;
+}
+
+int close_device(const char *device)
+{
+    int i;
+    for(i = 1; i < nfds; i++) {
+        if(strcmp(device_names[i], device) == 0) {
+            int count = nfds - i - 1;
+            free(device_names[i]);
+            memmove(device_names + i, device_names + i + 1, sizeof(device_names[0]) * count);
+            memmove(ufds + i, ufds + i + 1, sizeof(ufds[0]) * count);
+            nfds--;
+            return 0;
+        }
+    }
+    return -1;
+}
+
+static int read_notify(const char *dirname, int nfd)
+{
+    int res;
+    char devname[PATH_MAX];
+    char *filename;
+    char event_buf[512];
+    int event_size;
+    int event_pos = 0;
+    struct inotify_event *event;
+
+    res = read(nfd, event_buf, sizeof(event_buf));
+    if(res < (int)sizeof(*event)) {
+        if(errno == EINTR)
+            return 0;
+        fprintf(stderr, "could not get event, %s\n", strerror(errno));
+        return 1;
+    }
+    //printf("got %d bytes of event information\n", res);
+
+    strcpy(devname, dirname);
+    filename = devname + strlen(devname);
+    *filename++ = '/';
+
+    while(res >= (int)sizeof(*event)) {
+        event = (struct inotify_event *)(event_buf + event_pos);
+        //printf("%d: %08x \"%s\"\n", event->wd, event->mask, event->len ? event->name : "");
+        if(event->len) {
+            strcpy(filename, event->name);
+            if(event->mask & IN_CREATE) {
+                open_device(devname);
+            }
+            else {
+                close_device(devname);
+            }
+        }
+        event_size = sizeof(*event) + event->len;
+        res -= event_size;
+        event_pos += event_size;
+    }
+    return 0;
+}
+
+static int scan_dir(const char *dirname)
+{
+    char devname[PATH_MAX];
+    char *filename;
+    DIR *dir;
+    struct dirent *de;
+    dir = opendir(dirname);
+    if(dir == NULL)
+        return -1;
+    strcpy(devname, dirname);
+    filename = devname + strlen(devname);
+    *filename++ = '/';
+    while((de = readdir(dir))) {
+        if(de->d_name[0] == '.' &&
+           (de->d_name[1] == '\0' ||
+            (de->d_name[1] == '.' && de->d_name[2] == '\0')))
+            continue;
+        strcpy(filename, de->d_name);
+        open_device(devname);
+    }
+    closedir(dir);
+    return 0;
+}
+
+int init_getevent()
+{
+    int res;
+    const char *device_path = "/dev/input";
+
+    nfds = 1;
+    ufds = calloc(1, sizeof(ufds[0]));
+    ufds[0].fd = inotify_init();
+    ufds[0].events = POLLIN;
+
+	res = inotify_add_watch(ufds[0].fd, device_path, IN_DELETE | IN_CREATE);
+    if(res < 0) {
+        return 1;
+    }
+    res = scan_dir(device_path);
+    if(res < 0) {
+        return 1;
+    }
+    return 0;
+}
+
+void uninit_getevent()
+{
+    int i;
+    for(i = 0; i < nfds; i++) {
+        close(ufds[i].fd);
+    }
+    free(ufds);
+    ufds = 0;
+    nfds = 0;
+}
+
+int get_event(struct input_event* event, int timeout)
+{
+    int res;
+    int i;
+    int pollres;
+    const char *device_path = "/dev/input";
+    while(1) {
+        pollres = poll(ufds, nfds, timeout);
+        if (pollres == 0) {
+            return 1;
+        }
+        if(ufds[0].revents & POLLIN) {
+            read_notify(device_path, ufds[0].fd);
+        }
+        for(i = 1; i < nfds; i++) {
+            if(ufds[i].revents) {
+                if(ufds[i].revents & POLLIN) {
+                    res = read(ufds[i].fd, event, sizeof(*event));
+                    if(res < (int)sizeof(event)) {
+                        fprintf(stderr, "could not get event\n");
+                        return -1;
+                    }
+                    return 0;
+                }
+            }
+        }
+    }
+    return 0;
+}
diff --git a/debuggerd/pr-support.c b/debuggerd/pr-support.c
new file mode 100644
index 00000000..358d9b77
--- /dev/null
+++ b/debuggerd/pr-support.c
@@ -0,0 +1,345 @@
+/* ARM EABI compliant unwinding routines
+   Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+   Contributed by Paul Brook
+ 
+   This file is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   In addition to the permissions in the GNU General Public License, the
+   Free Software Foundation gives you unlimited permission to link the
+   compiled version of this file into combinations with other programs,
+   and to distribute those combinations without any restriction coming
+   from the use of this file.  (The General Public License restrictions
+   do apply in other respects; for example, they cover modification of
+   the file, and distribution when not linked into a combine
+   executable.)
+
+   This file is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.  If not, write to
+   the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+/****************************************************************************
+ * The functions here are derived from gcc/config/arm/pr-support.c from the 
+ * 4.3.x release. The main changes here involve the use of ptrace to retrieve
+ * memory/processor states from a remote process.
+ ****************************************************************************/
+
+#include <sys/types.h>
+#include <unwind.h>
+
+#include "utility.h"
+
+/* We add a prototype for abort here to avoid creating a dependency on
+   target headers.  */
+extern void abort (void);
+
+/* Derived from _Unwind_VRS_Pop to use ptrace */
+extern _Unwind_VRS_Result 
+unwind_VRS_Pop_with_ptrace (_Unwind_Context *context, 
+                            _Unwind_VRS_RegClass regclass, 
+                            _uw discriminator, 
+                            _Unwind_VRS_DataRepresentation representation, 
+                            pid_t pid);
+
+typedef struct _ZSt9type_info type_info; /* This names C++ type_info type */
+
+/* Misc constants.  */
+#define R_IP    12
+#define R_SP    13
+#define R_LR    14
+#define R_PC    15
+
+#define uint32_highbit (((_uw) 1) << 31)
+
+void __attribute__((weak)) __cxa_call_unexpected(_Unwind_Control_Block *ucbp);
+
+/* Unwind descriptors.  */
+
+typedef struct
+{
+  _uw16 length;
+  _uw16 offset;
+} EHT16;
+
+typedef struct
+{
+  _uw length;
+  _uw offset;
+} EHT32;
+
+/* Personality routine helper functions.  */
+
+#define CODE_FINISH (0xb0)
+
+/* Derived from next_unwind_byte to use ptrace */
+/* Return the next byte of unwinding information, or CODE_FINISH if there is
+   no data remaining.  */
+static inline _uw8
+next_unwind_byte_with_ptrace (__gnu_unwind_state * uws, pid_t pid)
+{
+  _uw8 b;
+
+  if (uws->bytes_left == 0)
+    {
+      /* Load another word */
+      if (uws->words_left == 0)
+	return CODE_FINISH; /* Nothing left.  */
+      uws->words_left--;
+      uws->data = get_remote_word(pid, uws->next);
+      uws->next++;
+      uws->bytes_left = 3;
+    }
+  else
+    uws->bytes_left--;
+
+  /* Extract the most significant byte.  */
+  b = (uws->data >> 24) & 0xff;
+  uws->data <<= 8;
+  return b;
+}
+
+/* Execute the unwinding instructions described by UWS.  */
+_Unwind_Reason_Code
+unwind_execute_with_ptrace(_Unwind_Context * context, __gnu_unwind_state * uws,
+                           pid_t pid)
+{
+  _uw op;
+  int set_pc;
+  _uw reg;
+
+  set_pc = 0;
+  for (;;)
+    {
+      op = next_unwind_byte_with_ptrace (uws, pid);
+      if (op == CODE_FINISH)
+	{
+	  /* If we haven't already set pc then copy it from lr.  */
+	  if (!set_pc)
+	    {
+	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_LR, _UVRSD_UINT32,
+			       &reg);
+	      _Unwind_VRS_Set (context, _UVRSC_CORE, R_PC, _UVRSD_UINT32,
+			       &reg);
+	      set_pc = 1;
+	    }
+	  /* Drop out of the loop.  */
+	  break;
+	}
+      if ((op & 0x80) == 0)
+	{
+	  /* vsp = vsp +- (imm6 << 2 + 4).  */
+	  _uw offset;
+
+	  offset = ((op & 0x3f) << 2) + 4;
+	  _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &reg);
+	  if (op & 0x40)
+	    reg -= offset;
+	  else
+	    reg += offset;
+	  _Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &reg);
+	  continue;
+	}
+      
+      if ((op & 0xf0) == 0x80)
+	{
+	  op = (op << 8) | next_unwind_byte_with_ptrace (uws, pid);
+	  if (op == 0x8000)
+	    {
+	      /* Refuse to unwind.  */
+	      return _URC_FAILURE;
+	    }
+	  /* Pop r4-r15 under mask.  */
+	  op = (op << 4) & 0xfff0;
+	  if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_CORE, op, _UVRSD_UINT32, 
+                                      pid)
+	      != _UVRSR_OK)
+	    return _URC_FAILURE;
+	  if (op & (1 << R_PC))
+	    set_pc = 1;
+	  continue;
+	}
+      if ((op & 0xf0) == 0x90)
+	{
+	  op &= 0xf;
+	  if (op == 13 || op == 15)
+	    /* Reserved.  */
+	    return _URC_FAILURE;
+	  /* vsp = r[nnnn].  */
+	  _Unwind_VRS_Get (context, _UVRSC_CORE, op, _UVRSD_UINT32, &reg);
+	  _Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, &reg);
+	  continue;
+	}
+      if ((op & 0xf0) == 0xa0)
+	{
+	  /* Pop r4-r[4+nnn], [lr].  */
+	  _uw mask;
+	  
+	  mask = (0xff0 >> (7 - (op & 7))) & 0xff0;
+	  if (op & 8)
+	    mask |= (1 << R_LR);
+	  if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_CORE, mask, _UVRSD_UINT32,
+                                      pid)
+	      != _UVRSR_OK)
+	    return _URC_FAILURE;
+	  continue;
+	}
+      if ((op & 0xf0) == 0xb0)
+	{
+	  /* op == 0xb0 already handled.  */
+	  if (op == 0xb1)
+	    {
+	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      if (op == 0 || ((op & 0xf0) != 0))
+		/* Spare.  */
+		return _URC_FAILURE;
+	      /* Pop r0-r4 under mask.  */
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_CORE, op, 
+                                          _UVRSD_UINT32, pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  if (op == 0xb2)
+	    {
+	      /* vsp = vsp + 0x204 + (uleb128 << 2).  */
+	      int shift;
+
+	      _Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
+			       &reg);
+	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      shift = 2;
+	      while (op & 0x80)
+		{
+		  reg += ((op & 0x7f) << shift);
+		  shift += 7;
+		  op = next_unwind_byte_with_ptrace (uws, pid);
+		}
+	      reg += ((op & 0x7f) << shift) + 0x204;
+	      _Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
+			       &reg);
+	      continue;
+	    }
+	  if (op == 0xb3)
+	    {
+	      /* Pop VFP registers with fldmx.  */
+	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_VFP, op, _UVRSD_VFPX, 
+                                          pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  if ((op & 0xfc) == 0xb4)
+	    {
+	      /* Pop FPA E[4]-E[4+nn].  */
+	      op = 0x40000 | ((op & 3) + 1);
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_FPA, op, _UVRSD_FPAX, 
+                                          pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  /* op & 0xf8 == 0xb8.  */
+	  /* Pop VFP D[8]-D[8+nnn] with fldmx.  */
+	  op = 0x80000 | ((op & 7) + 1);
+	  if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_VFP, op, _UVRSD_VFPX, pid)
+	      != _UVRSR_OK)
+	    return _URC_FAILURE;
+	  continue;
+	}
+      if ((op & 0xf0) == 0xc0)
+	{
+	  if (op == 0xc6)
+	    {
+	      /* Pop iWMMXt D registers.  */
+	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_WMMXD, op, 
+                                          _UVRSD_UINT64, pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  if (op == 0xc7)
+	    {
+	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      if (op == 0 || (op & 0xf0) != 0)
+		/* Spare.  */
+		return _URC_FAILURE;
+	      /* Pop iWMMXt wCGR{3,2,1,0} under mask.  */
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_WMMXC, op, 
+                                          _UVRSD_UINT32, pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  if ((op & 0xf8) == 0xc0)
+	    {
+	      /* Pop iWMMXt wR[10]-wR[10+nnn].  */
+	      op = 0xa0000 | ((op & 0xf) + 1);
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_WMMXD, op, 
+                                          _UVRSD_UINT64, pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  if (op == 0xc8)
+	    {
+#ifndef __VFP_FP__
+ 	      /* Pop FPA registers.  */
+ 	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
+ 	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_FPA, op, _UVRSD_FPAX,
+                                          pid)
+ 		  != _UVRSR_OK)
+ 		return _URC_FAILURE;
+ 	      continue;
+#else
+              /* Pop VFPv3 registers D[16+ssss]-D[16+ssss+cccc] with vldm.  */
+              op = next_unwind_byte_with_ptrace (uws, pid);
+              op = (((op & 0xf0) + 16) << 12) | ((op & 0xf) + 1);
+              if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_VFP, op, 
+                                              _UVRSD_DOUBLE, pid)
+                  != _UVRSR_OK)
+                return _URC_FAILURE;
+              continue;
+#endif
+	    }
+	  if (op == 0xc9)
+	    {
+	      /* Pop VFP registers with fldmd.  */
+	      op = next_unwind_byte_with_ptrace (uws, pid);
+	      op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
+	      if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_VFP, op, 
+                                          _UVRSD_DOUBLE, pid)
+		  != _UVRSR_OK)
+		return _URC_FAILURE;
+	      continue;
+	    }
+	  /* Spare.  */
+	  return _URC_FAILURE;
+	}
+      if ((op & 0xf8) == 0xd0)
+	{
+	  /* Pop VFP D[8]-D[8+nnn] with fldmd.  */
+	  op = 0x80000 | ((op & 7) + 1);
+	  if (unwind_VRS_Pop_with_ptrace (context, _UVRSC_VFP, op, _UVRSD_DOUBLE, 
+                                      pid)
+	      != _UVRSR_OK)
+	    return _URC_FAILURE;
+	  continue;
+	}
+      /* Spare.  */
+      return _URC_FAILURE;
+    }
+  return _URC_OK;
+}
diff --git a/debuggerd/unwind-arm.c b/debuggerd/unwind-arm.c
new file mode 100644
index 00000000..fdc0a6aa
--- /dev/null
+++ b/debuggerd/unwind-arm.c
@@ -0,0 +1,618 @@
+/* ARM EABI compliant unwinding routines.
+   Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+   Contributed by Paul Brook
+
+   This file is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   In addition to the permissions in the GNU General Public License, the
+   Free Software Foundation gives you unlimited permission to link the
+   compiled version of this file into combinations with other programs,
+   and to distribute those combinations without any restriction coming
+   from the use of this file.  (The General Public License restrictions
+   do apply in other respects; for example, they cover modification of
+   the file, and distribution when not linked into a combine
+   executable.)
+
+   This file is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; see the file COPYING.  If not, write to
+   the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+/****************************************************************************
+ * The functions here are derived from gcc/config/arm/unwind-arm.c from the 
+ * 4.3.x release. The main changes here involve the use of ptrace to retrieve
+ * memory/processor states from a remote process.
+ ****************************************************************************/
+
+#include <cutils/logd.h>
+#include <sys/ptrace.h>
+#include <unwind.h>
+#include "utility.h"
+
+typedef struct _ZSt9type_info type_info; /* This names C++ type_info type */
+
+void __attribute__((weak)) __cxa_call_unexpected(_Unwind_Control_Block *ucbp);
+bool __attribute__((weak)) __cxa_begin_cleanup(_Unwind_Control_Block *ucbp);
+bool __attribute__((weak)) __cxa_type_match(_Unwind_Control_Block *ucbp,
+                        const type_info *rttip,
+                        bool is_reference,
+                        void **matched_object);
+
+/* Misc constants.  */
+#define R_IP	12
+#define R_SP	13
+#define R_LR	14
+#define R_PC	15
+
+#define EXIDX_CANTUNWIND 1
+#define uint32_highbit (((_uw) 1) << 31)
+
+#define UCB_FORCED_STOP_FN(ucbp) ((ucbp)->unwinder_cache.reserved1)
+#define UCB_PR_ADDR(ucbp) ((ucbp)->unwinder_cache.reserved2)
+#define UCB_SAVED_CALLSITE_ADDR(ucbp) ((ucbp)->unwinder_cache.reserved3)
+#define UCB_FORCED_STOP_ARG(ucbp) ((ucbp)->unwinder_cache.reserved4)
+
+struct core_regs
+{
+  _uw r[16];
+};
+
+/* We use normal integer types here to avoid the compiler generating
+   coprocessor instructions.  */
+struct vfp_regs
+{
+  _uw64 d[16];
+  _uw pad;
+};
+
+struct vfpv3_regs
+{
+  /* Always populated via VSTM, so no need for the "pad" field from
+     vfp_regs (which is used to store the format word for FSTMX).  */
+  _uw64 d[16];
+};
+
+struct fpa_reg
+{
+  _uw w[3];
+};
+
+struct fpa_regs
+{
+  struct fpa_reg f[8];
+};
+
+struct wmmxd_regs
+{
+  _uw64 wd[16];
+};
+
+struct wmmxc_regs
+{
+  _uw wc[4];
+};
+
+/* Unwind descriptors.  */
+
+typedef struct
+{
+  _uw16 length;
+  _uw16 offset;
+} EHT16;
+
+typedef struct
+{
+  _uw length;
+  _uw offset;
+} EHT32;
+
+/* The ABI specifies that the unwind routines may only use core registers,
+   except when actually manipulating coprocessor state.  This allows
+   us to write one implementation that works on all platforms by
+   demand-saving coprocessor registers.
+
+   During unwinding we hold the coprocessor state in the actual hardware
+   registers and allocate demand-save areas for use during phase1
+   unwinding.  */
+
+typedef struct
+{
+  /* The first fields must be the same as a phase2_vrs.  */
+  _uw demand_save_flags;
+  struct core_regs core;
+  _uw prev_sp; /* Only valid during forced unwinding.  */
+  struct vfp_regs vfp;
+  struct vfpv3_regs vfp_regs_16_to_31;
+  struct fpa_regs fpa;
+  struct wmmxd_regs wmmxd;
+  struct wmmxc_regs wmmxc;
+} phase1_vrs;
+
+/* This must match the structure created by the assembly wrappers.  */
+typedef struct
+{
+  _uw demand_save_flags;
+  struct core_regs core;
+} phase2_vrs;
+
+
+/* An exception index table entry.  */
+
+typedef struct __EIT_entry
+{
+  _uw fnoffset;
+  _uw content;
+} __EIT_entry;
+
+/* Derived version to use ptrace */
+typedef _Unwind_Reason_Code (*personality_routine_with_ptrace)
+           (_Unwind_State,
+			_Unwind_Control_Block *,
+			_Unwind_Context *,
+            pid_t);
+
+/* Derived version to use ptrace */
+/* ABI defined personality routines.  */
+static _Unwind_Reason_Code unwind_cpp_pr0_with_ptrace (_Unwind_State,
+    _Unwind_Control_Block *, _Unwind_Context *, pid_t);
+static _Unwind_Reason_Code unwind_cpp_pr1_with_ptrace (_Unwind_State,
+    _Unwind_Control_Block *, _Unwind_Context *, pid_t);
+static _Unwind_Reason_Code unwind_cpp_pr2_with_ptrace (_Unwind_State,
+    _Unwind_Control_Block *, _Unwind_Context *, pid_t);
+
+/* Execute the unwinding instructions described by UWS.  */
+extern _Unwind_Reason_Code
+unwind_execute_with_ptrace(_Unwind_Context * context, __gnu_unwind_state * uws,
+                           pid_t pid);
+
+/* Derived version to use ptrace. Only handles core registers. Disregards
+ * FP and others. 
+ */
+/* ABI defined function to pop registers off the stack.  */
+
+_Unwind_VRS_Result unwind_VRS_Pop_with_ptrace (_Unwind_Context *context,
+				    _Unwind_VRS_RegClass regclass,
+				    _uw discriminator,
+				    _Unwind_VRS_DataRepresentation representation,
+                    pid_t pid)
+{
+  phase1_vrs *vrs = (phase1_vrs *) context;
+
+  switch (regclass)
+    {
+    case _UVRSC_CORE:
+      {
+	_uw *ptr;
+	_uw mask;
+	int i;
+
+	if (representation != _UVRSD_UINT32)
+	  return _UVRSR_FAILED;
+
+	mask = discriminator & 0xffff;
+	ptr = (_uw *) vrs->core.r[R_SP];
+	/* Pop the requested registers.  */
+	for (i = 0; i < 16; i++)
+	  {
+	    if (mask & (1 << i)) {
+	      vrs->core.r[i] = get_remote_word(pid, ptr);
+          ptr++;
+        }
+	  }
+	/* Writeback the stack pointer value if it wasn't restored.  */
+	if ((mask & (1 << R_SP)) == 0)
+	  vrs->core.r[R_SP] = (_uw) ptr;
+      }
+      return _UVRSR_OK;
+
+    default:
+      return _UVRSR_FAILED;
+    }
+}
+
+/* Core unwinding functions.  */
+
+/* Calculate the address encoded by a 31-bit self-relative offset at address
+   P.  */
+static inline _uw
+selfrel_offset31 (const _uw *p, pid_t pid)
+{
+  _uw offset = get_remote_word(pid, (void*)p);
+
+  //offset = *p;
+  /* Sign extend to 32 bits.  */
+  if (offset & (1 << 30))
+    offset |= 1u << 31;
+  else
+    offset &= ~(1u << 31);
+
+  return offset + (_uw) p;
+}
+
+
+/* Perform a binary search for RETURN_ADDRESS in TABLE.  The table contains
+   NREC entries.  */
+
+static const __EIT_entry *
+search_EIT_table (const __EIT_entry * table, int nrec, _uw return_address,
+                  pid_t pid)
+{
+  _uw next_fn;
+  _uw this_fn;
+  int n, left, right;
+
+  if (nrec == 0)
+    return (__EIT_entry *) 0;
+
+  left = 0;
+  right = nrec - 1;
+
+  while (1)
+    {
+      n = (left + right) / 2;
+      this_fn = selfrel_offset31 (&table[n].fnoffset, pid);
+      if (n != nrec - 1)
+	next_fn = selfrel_offset31 (&table[n + 1].fnoffset, pid) - 1;
+      else
+	next_fn = (_uw)0 - 1;
+
+      if (return_address < this_fn)
+	{
+	  if (n == left)
+	    return (__EIT_entry *) 0;
+	  right = n - 1;
+	}
+      else if (return_address <= next_fn)
+	return &table[n];
+      else
+	left = n + 1;
+    }
+}
+
+/* Find the exception index table eintry for the given address. */
+static const __EIT_entry*
+get_eitp(_uw return_address, pid_t pid, mapinfo *map, mapinfo **containing_map)
+{
+  const __EIT_entry *eitp = NULL;
+  int nrec;
+  mapinfo *mi;
+  
+  /* The return address is the address of the instruction following the
+     call instruction (plus one in thumb mode).  If this was the last
+     instruction in the function the address will lie in the following
+     function.  Subtract 2 from the address so that it points within the call
+     instruction itself.  */
+  if (return_address >= 2)
+      return_address -= 2;
+
+  for (mi = map; mi != NULL; mi = mi->next) {
+    if (return_address >= mi->start && return_address <= mi->end) break;
+  }
+
+  if (mi) {
+    if (containing_map) *containing_map = mi;
+    eitp = (__EIT_entry *) mi->exidx_start;
+    nrec = (mi->exidx_end - mi->exidx_start)/sizeof(__EIT_entry);
+    eitp = search_EIT_table (eitp, nrec, return_address, pid);
+  }
+  return eitp;
+}
+
+/* Find the exception index table eintry for the given address.
+   Fill in the relevant fields of the UCB.
+   Returns _URC_FAILURE if an error occurred, _URC_OK on success.  */
+
+static _Unwind_Reason_Code
+get_eit_entry (_Unwind_Control_Block *ucbp, _uw return_address, pid_t pid, 
+               mapinfo *map, mapinfo **containing_map)
+{
+  const __EIT_entry *eitp;
+  
+  eitp = get_eitp(return_address, pid, map, containing_map);
+
+  if (!eitp)
+    {
+      UCB_PR_ADDR (ucbp) = 0;
+      return _URC_FAILURE;
+    }
+  ucbp->pr_cache.fnstart = selfrel_offset31 (&eitp->fnoffset, pid);
+
+  _uw eitp_content = get_remote_word(pid, (void *)&eitp->content);
+
+  /* Can this frame be unwound at all?  */
+  if (eitp_content == EXIDX_CANTUNWIND)
+    {
+      UCB_PR_ADDR (ucbp) = 0;
+      return _URC_END_OF_STACK;
+    }
+
+  /* Obtain the address of the "real" __EHT_Header word.  */
+
+  if (eitp_content & uint32_highbit)
+    {
+      /* It is immediate data.  */
+      ucbp->pr_cache.ehtp = (_Unwind_EHT_Header *)&eitp->content;
+      ucbp->pr_cache.additional = 1;
+    }
+  else
+    {
+      /* The low 31 bits of the content field are a self-relative
+	 offset to an _Unwind_EHT_Entry structure.  */
+      ucbp->pr_cache.ehtp =
+	(_Unwind_EHT_Header *) selfrel_offset31 (&eitp->content, pid);
+      ucbp->pr_cache.additional = 0;
+    }
+
+  /* Discover the personality routine address.  */
+  if (get_remote_word(pid, ucbp->pr_cache.ehtp) & (1u << 31))
+    {
+      /* One of the predefined standard routines.  */
+      _uw idx = (get_remote_word(pid, ucbp->pr_cache.ehtp) >> 24) & 0xf;
+      if (idx == 0)
+	UCB_PR_ADDR (ucbp) = (_uw) &unwind_cpp_pr0_with_ptrace;
+      else if (idx == 1)
+	UCB_PR_ADDR (ucbp) = (_uw) &unwind_cpp_pr1_with_ptrace;
+      else if (idx == 2)
+	UCB_PR_ADDR (ucbp) = (_uw) &unwind_cpp_pr2_with_ptrace;
+      else
+	{ /* Failed */
+	  UCB_PR_ADDR (ucbp) = 0;
+	  return _URC_FAILURE;
+	}
+    } 
+  else
+    {
+      /* Execute region offset to PR */
+      UCB_PR_ADDR (ucbp) = selfrel_offset31 (ucbp->pr_cache.ehtp, pid);
+      /* Since we are unwinding the stack from a different process, it is
+       * impossible to execute the personality routine in debuggerd. Punt here.
+       */
+	  return _URC_FAILURE;
+    }
+  return _URC_OK;
+}
+
+/* Print out the current call level, pc, and module name in the crash log */
+static _Unwind_Reason_Code log_function(_Unwind_Context *context, int tfd,
+                                        int stack_level,
+                                        mapinfo *map,
+                                        unsigned int sp_list[],
+                                        bool at_fault)
+{
+    _uw pc;
+    phase2_vrs *vrs = (phase2_vrs*) context;
+    const mapinfo *mi;
+    bool only_in_tombstone = !at_fault;
+
+    if (stack_level < STACK_CONTENT_DEPTH) {
+        sp_list[stack_level] = vrs->core.r[R_SP];
+    }
+    pc = vrs->core.r[R_PC];
+
+    // Top level frame
+    if (stack_level == 0) {
+        pc &= ~1;
+    }
+    // For deeper framers, rollback pc by one instruction
+    else {
+        pc = vrs->core.r[R_PC];
+        // Thumb mode
+        if (pc & 1) {
+            pc = (pc & ~1) - 2;
+        }
+        else { 
+            pc -= 4;
+        }
+    }
+
+    mi = pc_to_mapinfo(map, pc);
+
+    _LOG(tfd, only_in_tombstone, 
+         "         #%02d  pc %08x  %s\n", stack_level, pc, 
+         mi ? mi->name : "");
+
+    return _URC_NO_REASON;
+}
+
+/* Derived from __gnu_Unwind_Backtrace to use ptrace */
+/* Perform stack backtrace through unwind data. Return the level of stack it
+ * unwinds.
+ */
+int unwind_backtrace_with_ptrace(int tfd, pid_t pid, mapinfo *map, 
+                                 unsigned int sp_list[], int *frame0_pc_sane,
+                                 bool at_fault)
+{
+    phase1_vrs saved_vrs;
+    _Unwind_Reason_Code code = _URC_OK;
+    struct pt_regs r;
+    int i;
+    int stack_level = 0;
+
+    _Unwind_Control_Block ucb;
+    _Unwind_Control_Block *ucbp = &ucb;
+
+    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) return 0;
+
+    for (i = 0; i < 16; i++) {
+        saved_vrs.core.r[i] = r.uregs[i];
+        /*
+        _LOG(tfd, "r[%d] = 0x%x\n", i, saved_vrs.core.r[i]);
+        */
+    }
+
+    /* Set demand-save flags.  */
+    saved_vrs.demand_save_flags = ~(_uw) 0;
+
+    /* 
+     * If the app crashes because of calling the weeds, we cannot pass the PC 
+     * to the usual unwinding code as the EXIDX mapping will fail. 
+     * Instead, we simply print out the 0 as the top frame, and resume the 
+     * unwinding process with the value stored in LR.
+     */
+    if (get_eitp(saved_vrs.core.r[R_PC], pid, map, NULL) == NULL) { 
+        *frame0_pc_sane = 0;
+        log_function ((_Unwind_Context *) &saved_vrs, tfd, stack_level, 
+                      map, sp_list, at_fault);
+        saved_vrs.core.r[R_PC] = saved_vrs.core.r[R_LR];
+        stack_level++;
+    }
+
+    do {
+        mapinfo *this_map = NULL;
+        /* Find the entry for this routine.  */
+        if (get_eit_entry(ucbp, saved_vrs.core.r[R_PC], pid, map, &this_map)
+            != _URC_OK) {
+            /* Uncomment the code below to study why the unwinder failed */
+#if 0
+            /* Shed more debugging info for stack unwinder improvement */
+            if (this_map) {
+                _LOG(tfd, 1, 
+                     "Relative PC=%#x from %s not contained in EXIDX\n", 
+                     saved_vrs.core.r[R_PC] - this_map->start, this_map->name);
+            }
+            _LOG(tfd, 1, "PC=%#x SP=%#x\n", 
+                 saved_vrs.core.r[R_PC], saved_vrs.core.r[R_SP]);
+#endif
+            code = _URC_FAILURE;
+            break;
+        }
+
+        /* The dwarf unwinder assumes the context structure holds things
+        like the function and LSDA pointers.  The ARM implementation
+        caches these in the exception header (UCB).  To avoid
+        rewriting everything we make the virtual IP register point at
+        the UCB.  */
+        _Unwind_SetGR((_Unwind_Context *)&saved_vrs, 12, (_Unwind_Ptr) ucbp);
+
+        /* Call log function.  */
+        if (log_function ((_Unwind_Context *) &saved_vrs, tfd, stack_level, 
+                          map, sp_list, at_fault) != _URC_NO_REASON) {
+            code = _URC_FAILURE;
+            break;
+        }
+        stack_level++;
+
+        /* Call the pr to decide what to do.  */
+        code = ((personality_routine_with_ptrace) UCB_PR_ADDR (ucbp))(
+                _US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND, ucbp, 
+                (void *) &saved_vrs, pid);
+    /* 
+     * In theory the unwinding process will stop when the end of stack is
+     * reached or there is no unwinding information for the code address.
+     * To add another level of guarantee that the unwinding process
+     * will terminate we will stop it when the STACK_CONTENT_DEPTH is reached.
+     */
+    } while (code != _URC_END_OF_STACK && code != _URC_FAILURE && 
+             stack_level < STACK_CONTENT_DEPTH);
+    return stack_level;
+}
+
+
+/* Derived version to use ptrace */
+/* Common implementation for ARM ABI defined personality routines.
+   ID is the index of the personality routine, other arguments are as defined
+   by __aeabi_unwind_cpp_pr{0,1,2}.  */
+
+static _Unwind_Reason_Code
+unwind_pr_common_with_ptrace (_Unwind_State state,
+			_Unwind_Control_Block *ucbp,
+			_Unwind_Context *context,
+			int id,
+            pid_t pid)
+{
+  __gnu_unwind_state uws;
+  _uw *data;
+  int phase2_call_unexpected_after_unwind = 0;
+
+  state &= _US_ACTION_MASK;
+
+  data = (_uw *) ucbp->pr_cache.ehtp;
+  uws.data = get_remote_word(pid, data);
+  data++;
+  uws.next = data;
+  if (id == 0)
+    {
+      uws.data <<= 8;
+      uws.words_left = 0;
+      uws.bytes_left = 3;
+    }
+  else
+    {
+      uws.words_left = (uws.data >> 16) & 0xff;
+      uws.data <<= 16;
+      uws.bytes_left = 2;
+      data += uws.words_left;
+    }
+
+  /* Restore the saved pointer.  */
+  if (state == _US_UNWIND_FRAME_RESUME)
+    data = (_uw *) ucbp->cleanup_cache.bitpattern[0];
+
+  if ((ucbp->pr_cache.additional & 1) == 0)
+    {
+      /* Process descriptors.  */
+      while (get_remote_word(pid, data)) {
+      /**********************************************************************
+       * The original code here seems to deal with exceptions that are not
+       * applicable in our toolchain, thus there is no way to test it for now.
+       * Instead of leaving it here and causing potential instability in
+       * debuggerd, we'd better punt here and leave the stack unwound.
+       * In the future when we discover cases where the stack should be unwound
+       * further but is not, we can revisit the code here.
+       **********************************************************************/
+        return _URC_FAILURE;
+	  }
+	  /* Finished processing this descriptor.  */
+    }
+
+  if (unwind_execute_with_ptrace (context, &uws, pid) != _URC_OK)
+    return _URC_FAILURE;
+
+  if (phase2_call_unexpected_after_unwind)
+    {
+      /* Enter __cxa_unexpected as if called from the call site.  */
+      _Unwind_SetGR (context, R_LR, _Unwind_GetGR (context, R_PC));
+      _Unwind_SetGR (context, R_PC, (_uw) &__cxa_call_unexpected);
+      return _URC_INSTALL_CONTEXT;
+    }
+
+  return _URC_CONTINUE_UNWIND;
+}
+
+
+/* ABI defined personality routine entry points.  */
+
+static _Unwind_Reason_Code
+unwind_cpp_pr0_with_ptrace (_Unwind_State state,
+			_Unwind_Control_Block *ucbp,
+			_Unwind_Context *context,
+            pid_t pid)
+{
+  return unwind_pr_common_with_ptrace (state, ucbp, context, 0, pid);
+}
+
+static _Unwind_Reason_Code
+unwind_cpp_pr1_with_ptrace (_Unwind_State state,
+			_Unwind_Control_Block *ucbp,
+			_Unwind_Context *context,
+            pid_t pid)
+{
+  return unwind_pr_common_with_ptrace (state, ucbp, context, 1, pid);
+}
+
+static _Unwind_Reason_Code
+unwind_cpp_pr2_with_ptrace (_Unwind_State state,
+			_Unwind_Control_Block *ucbp,
+			_Unwind_Context *context,
+            pid_t pid)
+{
+  return unwind_pr_common_with_ptrace (state, ucbp, context, 2, pid);
+}
diff --git a/debuggerd/utility.c b/debuggerd/utility.c
new file mode 100644
index 00000000..0cb790fd
--- /dev/null
+++ b/debuggerd/utility.c
@@ -0,0 +1,78 @@
+/* system/debuggerd/utility.c
+**
+** Copyright 2008, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#include <sys/ptrace.h>
+#include <sys/exec_elf.h>
+#include <assert.h>
+#include <errno.h>
+
+#include "utility.h"
+
+/* Get a word from pid using ptrace. The result is the return value. */
+int get_remote_word(int pid, void *src)
+{
+    return ptrace(PTRACE_PEEKTEXT, pid, src, NULL);
+}
+
+
+/* Handy routine to read aggregated data from pid using ptrace. The read 
+ * values are written to the dest locations directly. 
+ */
+void get_remote_struct(int pid, void *src, void *dst, size_t size)
+{
+    unsigned int i;
+
+    for (i = 0; i+4 <= size; i+=4) {
+        *(int *)(dst+i) = ptrace(PTRACE_PEEKTEXT, pid, src+i, NULL);
+    }
+
+    if (i < size) {
+        int val;
+
+        assert((size - i) < 4);
+        val = ptrace(PTRACE_PEEKTEXT, pid, src+i, NULL);
+        while (i < size) {
+            ((unsigned char *)dst)[i] = val & 0xff;
+            i++;
+            val >>= 8;
+        }
+    }
+}
+
+/* Map a pc address to the name of the containing ELF file */
+const char *map_to_name(mapinfo *mi, unsigned pc, const char* def)
+{
+    while(mi) {
+        if((pc >= mi->start) && (pc < mi->end)){
+            return mi->name;
+        }
+        mi = mi->next;
+    }
+    return def;
+}
+
+/* Find the containing map info for the pc */
+const mapinfo *pc_to_mapinfo(mapinfo *mi, unsigned pc)
+{
+    while(mi) {
+        if((pc >= mi->start) && (pc < mi->end)){
+            return mi;
+        }
+        mi = mi->next;
+    }
+    return NULL;
+}
diff --git a/debuggerd/utility.h b/debuggerd/utility.h
new file mode 100644
index 00000000..802e3ad2
--- /dev/null
+++ b/debuggerd/utility.h
@@ -0,0 +1,56 @@
+/* system/debuggerd/utility.h
+**
+** Copyright 2008, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#ifndef __utility_h
+#define __utility_h
+
+#include <stddef.h>
+#include <stdbool.h>
+
+#ifndef PT_ARM_EXIDX
+#define PT_ARM_EXIDX    0x70000001      /* .ARM.exidx segment */
+#endif
+
+#define STACK_CONTENT_DEPTH 32
+
+typedef struct mapinfo {
+    struct mapinfo *next;
+    unsigned start;
+    unsigned end;
+    unsigned exidx_start;
+    unsigned exidx_end;
+    char name[];
+} mapinfo;
+
+/* Get a word from pid using ptrace. The result is the return value. */
+extern int get_remote_word(int pid, void *src);
+
+/* Handy routine to read aggregated data from pid using ptrace. The read 
+ * values are written to the dest locations directly. 
+ */
+extern void get_remote_struct(int pid, void *src, void *dst, size_t size);
+
+/* Find the containing map for the pc */
+const mapinfo *pc_to_mapinfo (mapinfo *mi, unsigned pc);
+
+/* Map a pc address to the name of the containing ELF file */
+const char *map_to_name(mapinfo *mi, unsigned pc, const char* def);
+
+/* Log information onto the tombstone */
+extern void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...);
+
+#endif