1 files changed, 129 insertions, 0 deletions
diff --git a/libcutils/canned_fs_config.cpp b/libcutils/canned_fs_config.cpp
new file mode 100644
index 000000000..6b5763b16
--- /dev/null
+++ b/libcutils/canned_fs_config.cpp
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2014 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 <private/android_filesystem_config.h>
+#include <private/canned_fs_config.h>
+#include <private/fs_config.h>
+
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+    const char* path;
+    unsigned uid;
+    unsigned gid;
+    unsigned mode;
+    uint64_t capabilities;
+} Path;
+
+static Path* canned_data = NULL;
+static int canned_alloc = 0;
+static int canned_used = 0;
+
+static int path_compare(const void* a, const void* b) {
+    return strcmp(((Path*)a)->path, ((Path*)b)->path);
+}
+
+int load_canned_fs_config(const char* fn) {
+    char buf[PATH_MAX + 200];
+    FILE* f;
+
+    f = fopen(fn, "r");
+    if (f == NULL) {
+        fprintf(stderr, "failed to open %s: %s\n", fn, strerror(errno));
+        return -1;
+    }
+
+    while (fgets(buf, sizeof(buf), f)) {
+        Path* p;
+        char* token;
+        char* line = buf;
+        bool rootdir;
+
+        while (canned_used >= canned_alloc) {
+            canned_alloc = (canned_alloc+1) * 2;
+            canned_data = (Path*) realloc(canned_data, canned_alloc * sizeof(Path));
+        }
+        p = canned_data + canned_used;
+        if (line[0] == '/') line++;
+        rootdir = line[0] == ' ';
+        p->path = strdup(rootdir ? "" : strtok(line, " "));
+        p->uid = atoi(strtok(rootdir ? line : NULL, " "));
+        p->gid = atoi(strtok(NULL, " "));
+        p->mode = strtol(strtok(NULL, " "), NULL, 8);   // mode is in octal
+        p->capabilities = 0;
+
+        do {
+            token = strtok(NULL, " ");
+            if (token && strncmp(token, "capabilities=", 13) == 0) {
+                p->capabilities = strtoll(token+13, NULL, 0);
+                break;
+            }
+        } while (token);
+
+        canned_used++;
+    }
+
+    fclose(f);
+
+    qsort(canned_data, canned_used, sizeof(Path), path_compare);
+    printf("loaded %d fs_config entries\n", canned_used);
+
+    return 0;
+}
+
+static const int kDebugCannedFsConfig = 0;
+
+void canned_fs_config(const char* path, int dir, const char* target_out_path,
+                      unsigned* uid, unsigned* gid, unsigned* mode, uint64_t* capabilities) {
+    Path key, *p;
+
+    key.path = path;
+    if (path[0] == '/') key.path++; // canned paths lack the leading '/'
+    p = (Path*) bsearch(&key, canned_data, canned_used, sizeof(Path), path_compare);
+    if (p == NULL) {
+        fprintf(stderr, "failed to find [%s] in canned fs_config\n", path);
+        exit(1);
+    }
+    *uid = p->uid;
+    *gid = p->gid;
+    *mode = p->mode;
+    *capabilities = p->capabilities;
+
+    if (kDebugCannedFsConfig) {
+        // for debugging, run the built-in fs_config and compare the results.
+
+        unsigned c_uid, c_gid, c_mode;
+        uint64_t c_capabilities;
+
+        fs_config(path, dir, target_out_path, &c_uid, &c_gid, &c_mode, &c_capabilities);
+
+        if (c_uid != *uid) printf("%s uid %d %d\n", path, *uid, c_uid);
+        if (c_gid != *gid) printf("%s gid %d %d\n", path, *gid, c_gid);
+        if (c_mode != *mode) printf("%s mode 0%o 0%o\n", path, *mode, c_mode);
+        if (c_capabilities != *capabilities) {
+            printf("%s capabilities %" PRIx64 " %" PRIx64 "\n",
+                path,
+                *capabilities,
+                c_capabilities);
+        }
+    }
+}