Fix adb hang when subprocess dies early.

* Handling of the subprocess and its FD.
  This fixes http://b/3400254 "Many bugreports getting hung at the end in monkey"
  -  Start up a service thread that waits on the subprocess to terminate,
then closes the FD associated with it.
  -  Have the event handler select() with a timeout so that it can
  detect the closed FD. Select() with no timeout does not return when an FD is closed.
  - Have the event handler force a read on the closed FD to trigger the close sequence.
  - Migrate the "shell:blabla" handling to "#if !ADB_HOST" sections.
* Fix the race around OOM adjusting.
  - Do it in the child before exec() instead of the in the parent as the
   child could already have started or not (no /proc/pid/... yet).
* Allow for multi-threaded D() invocations to not clobber each other.
  - Allow locks across object files.
  - Add lock within D()
* Add some missing close(fd) calls
  - Match similar existing practices near dup2()
* Add extra D() invocations related to FD handling.
* Warn about using debugging as stderr/stdout is used for protocol.

Change-Id: Ie5c4a5e6bfbe3f22201adf5f9a205d32e069bf9d
Signed-off-by: JP Abgrall <jpa@google.com>

1 files changed, 34 insertions, 4 deletions

diff --git a/adb/adb.h b/adb/adb.h
index 0aa98d3d..7cbf3d33 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -123,7 +123,7 @@ struct asocket {
         /* socket-type-specific extradata */
     void *extra;
 
-    	/* A socket is bound to atransport */
+        /* A socket is bound to atransport */
     atransport *transport;
 };
 
@@ -344,20 +344,50 @@ typedef enum {
 
 #if ADB_TRACE
 
-  int     adb_trace_mask;
+// TODO(jpa): remove this after fixing fprintf() multithreading issue {
+// Can't include sysdeps.h, because framebuffer_service.c wants a different
+// close() than what sysdeps overrides when linking adbd.
 
+// Assume Linux.
+#ifndef _ADB_SYSDEPS_H
+#include <pthread.h>
+typedef  pthread_mutex_t          adb_mutex_t;
+#define  ADB_MUTEX(x)   extern adb_mutex_t  x;
+#include "mutex_list.h"
+#endif
+
+// }
+
+  extern int     adb_trace_mask;
+  extern unsigned char    adb_trace_output_count;
   void    adb_trace_init(void);
 
 #  define ADB_TRACING  ((adb_trace_mask & (1 << TRACE_TAG)) != 0)
 
   /* you must define TRACE_TAG before using this macro */
-  #define  D(...)                                      \
+#  define  D(...)                                      \
+        do {                                           \
+            if (ADB_TRACING) {                         \
+                adb_mutex_lock(&D_lock);               \
+                fprintf(stderr, "%s::%s():",           \
+                    __FILE__, __FUNCTION__);           \
+                fprintf(stderr, __VA_ARGS__ );         \
+                fflush(stderr);                        \
+                adb_mutex_unlock(&D_lock);             \
+           }                                           \
+        } while (0)
+#  define  DR(...)                                     \
         do {                                           \
-            if (ADB_TRACING)                           \
+            if (ADB_TRACING) {                         \
+                adb_mutex_lock(&D_lock);               \
                 fprintf(stderr, __VA_ARGS__ );         \
+                fflush(stderr);                        \
+                adb_mutex_unlock(&D_lock);             \
+           }                                           \
         } while (0)
 #else
 #  define  D(...)          ((void)0)
+#  define  DR(...)         ((void)0)
 #  define  ADB_TRACING     0
 #endif