Log debuggerd connection failures
Write a message to the log file if the signal handler is not able
to connect to debuggerd. This is especially handy if the failure
was caused by running out of file descriptors, since there's some
chance that the lack of fds relates to the crash.
Sample:
F libc : Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1)
F libc : Unable to open connection to debuggerd: Too many open files
Bug 5926330
Change-Id: I0ff210d82ab1db39b08f328bae5e08f67a69e5d7
diff --git a/linker/debugger.c b/linker/debugger.c
index 648dc78..ef8286c 100644
--- a/linker/debugger.c
+++ b/linker/debugger.c
@@ -126,6 +126,7 @@
*/
void debugger_signal_handler(int n, siginfo_t* info, void* unused)
{
+ char msgbuf[128];
unsigned tid;
int s;
@@ -134,7 +135,7 @@
tid = gettid();
s = socket_abstract_client("android:debuggerd", SOCK_STREAM);
- if(s >= 0) {
+ if (s >= 0) {
/* debugger knows our pid from the credentials on the
* local socket but we need to tell it our tid. It
* is paranoid and will verify that we are giving a tid
@@ -147,9 +148,24 @@
/* if the write failed, there is no point to read on
* the file descriptor. */
RETRY_ON_EINTR(ret, read(s, &tid, 1));
+ int savedErrno = errno;
notify_gdb_of_libraries();
+ errno = savedErrno;
}
+
+ if (ret < 0) {
+ /* read or write failed -- broken connection? */
+ format_buffer(msgbuf, sizeof(msgbuf),
+ "Failed while talking to debuggerd: %s", strerror(errno));
+ __libc_android_log_write(ANDROID_LOG_FATAL, "libc", msgbuf);
+ }
+
close(s);
+ } else {
+ /* socket failed; maybe process ran out of fds */
+ format_buffer(msgbuf, sizeof(msgbuf),
+ "Unable to open connection to debuggerd: %s", strerror(errno));
+ __libc_android_log_write(ANDROID_LOG_FATAL, "libc", msgbuf);
}
/* remove our net so we fault for real when we return */