debuggerd: don't leave a zombie child if crash_dump is killed.
If crash_dump dies before it gets a chance to write to the pipe we use
to let the debugged-process know that it successfully started, we
weren't cleaning up the child we fork to start it, leaving a zombie
child.
Bug: http://b/152119184
Test: debuggerd_test
Change-Id: Id01cc05f693995e9998941774f74ab8e3d8b4d8a
diff --git a/debuggerd/handler/debuggerd_handler.cpp b/debuggerd/handler/debuggerd_handler.cpp
index ac28fe9..121a074 100644
--- a/debuggerd/handler/debuggerd_handler.cpp
+++ b/debuggerd/handler/debuggerd_handler.cpp
@@ -417,23 +417,28 @@
// us to fork off a process to read memory from.
char buf[4];
rc = TEMP_FAILURE_RETRY(read(input_read.get(), &buf, sizeof(buf)));
- if (rc == -1) {
- async_safe_format_log(ANDROID_LOG_FATAL, "libc", "read of IPC pipe failed: %s", strerror(errno));
- return 1;
- } else if (rc == 0) {
- async_safe_format_log(ANDROID_LOG_FATAL, "libc", "crash_dump helper failed to exec");
- return 1;
- } else if (rc != 1) {
- async_safe_format_log(ANDROID_LOG_FATAL, "libc",
- "read of IPC pipe returned unexpected value: %zd", rc);
- return 1;
- } else if (buf[0] != '\1') {
- async_safe_format_log(ANDROID_LOG_FATAL, "libc", "crash_dump helper reported failure");
- return 1;
- }
- // crash_dump is ptracing us, fork off a copy of our address space for it to use.
- create_vm_process();
+ bool success = false;
+ if (rc == 1 && buf[0] == '\1') {
+ // crash_dump successfully started, and is ptracing us.
+ // Fork off a copy of our address space for it to use.
+ create_vm_process();
+ success = true;
+ } else {
+ // Something went wrong, log it.
+ if (rc == -1) {
+ async_safe_format_log(ANDROID_LOG_FATAL, "libc", "read of IPC pipe failed: %s",
+ strerror(errno));
+ } else if (rc == 0) {
+ async_safe_format_log(ANDROID_LOG_FATAL, "libc",
+ "crash_dump helper failed to exec, or was killed");
+ } else if (rc != 1) {
+ async_safe_format_log(ANDROID_LOG_FATAL, "libc",
+ "read of IPC pipe returned unexpected value: %zd", rc);
+ } else if (buf[0] != '\1') {
+ async_safe_format_log(ANDROID_LOG_FATAL, "libc", "crash_dump helper reported failure");
+ }
+ }
// Don't leave a zombie child.
int status;
@@ -444,14 +449,16 @@
async_safe_format_log(ANDROID_LOG_FATAL, "libc", "crash_dump helper crashed or stopped");
}
- if (thread_info->siginfo->si_signo != BIONIC_SIGNAL_DEBUGGER) {
- // For crashes, we don't need to minimize pause latency.
- // Wait for the dump to complete before having the process exit, to avoid being murdered by
- // ActivityManager or init.
- TEMP_FAILURE_RETRY(read(input_read, &buf, sizeof(buf)));
+ if (success) {
+ if (thread_info->siginfo->si_signo != BIONIC_SIGNAL_DEBUGGER) {
+ // For crashes, we don't need to minimize pause latency.
+ // Wait for the dump to complete before having the process exit, to avoid being murdered by
+ // ActivityManager or init.
+ TEMP_FAILURE_RETRY(read(input_read, &buf, sizeof(buf)));
+ }
}
- return 0;
+ return success ? 0 : 1;
}
static void resend_signal(siginfo_t* info) {