bionic: introduce libc.debug.malloc.program

libc.debug.malloc.program  provides an additional level of control over which
processes to enable libc.debug.malloc functionality for.  The string value of
libc.debug.malloc.program is matched against the program name; if the value of
libc.debug.malloc.program is a substring of the program name, then malloc debug
is applied to that program at whatever level libc.debug.malloc specifies.

If lib.debug.malloc.program is not specified, then libc.debug.malloc has the
same effect as before.

For example, to enable libc.deubug.malloc = 10 only to the mediaserver, do the
following:

   adb root # necessary for setprop
   adb setprop libc.debug.malloc.program mediaserver
   adb setprop libc.debug.malloc 10
   adb kill -9 $(pid mediaserver)

Change-Id: I6f01c12f033c8e2e015d73025369d7f1685ba200
Signed-off-by: Iliyan Malchev <malchev@google.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/libc/bionic/malloc_debug_common.c b/libc/bionic/malloc_debug_common.c
index b9fcbc49b..6837e393d 100644
--- a/libc/bionic/malloc_debug_common.c
+++ b/libc/bionic/malloc_debug_common.c
@@ -298,6 +298,7 @@ static void malloc_init_impl(void)
     unsigned int memcheck_enabled = 0;
     char env[PROP_VALUE_MAX];
     char memcheck_tracing[PROP_VALUE_MAX];
+    char debug_program[PROP_VALUE_MAX];
 
     /* Get custom malloc debug level. Note that emulator started with
      * memory checking option will have priority over debug level set in
@@ -325,6 +326,15 @@ static void malloc_init_impl(void)
         return;
     }
 
+    /* If libc.debug.malloc.program is set and is not a substring of progname,
+     * then exit.
+     */
+    if (__system_property_get("libc.debug.malloc.program", debug_program)) {
+        if (!strstr(__progname, debug_program)) {
+            return;
+        }
+    }
+
     // Lets see which .so must be loaded for the requested debug level
     switch (debug_level) {
         case 1: