Merge "Make libc signal handler output more like debuggerd."
diff --git a/linker/debugger.cpp b/linker/debugger.cpp
index aee9aa9..a44380c 100644
--- a/linker/debugger.cpp
+++ b/linker/debugger.cpp
@@ -29,6 +29,7 @@
#include "linker.h"
#include <errno.h>
+#include <inttypes.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
@@ -47,12 +48,12 @@
#endif
enum debugger_action_t {
- // dump a crash
- DEBUGGER_ACTION_CRASH,
- // dump a tombstone file
- DEBUGGER_ACTION_DUMP_TOMBSTONE,
- // dump a backtrace only back to the socket
- DEBUGGER_ACTION_DUMP_BACKTRACE,
+ // dump a crash
+ DEBUGGER_ACTION_CRASH,
+ // dump a tombstone file
+ DEBUGGER_ACTION_DUMP_TOMBSTONE,
+ // dump a backtrace only back to the socket
+ DEBUGGER_ACTION_DUMP_BACKTRACE,
};
/* message sent over the socket */
@@ -69,40 +70,39 @@
#define MAX_TASK_NAME_LEN (16)
static int socket_abstract_client(const char* name, int type) {
- sockaddr_un addr;
+ sockaddr_un addr;
- // Test with length +1 for the *initial* '\0'.
- size_t namelen = strlen(name);
- if ((namelen + 1) > sizeof(addr.sun_path)) {
- errno = EINVAL;
- return -1;
- }
+ // Test with length +1 for the *initial* '\0'.
+ size_t namelen = strlen(name);
+ if ((namelen + 1) > sizeof(addr.sun_path)) {
+ errno = EINVAL;
+ return -1;
+ }
- /* This is used for abstract socket namespace, we need
- * an initial '\0' at the start of the Unix socket path.
- *
- * Note: The path in this case is *not* supposed to be
- * '\0'-terminated. ("man 7 unix" for the gory details.)
- */
- memset(&addr, 0, sizeof(addr));
- addr.sun_family = AF_LOCAL;
- addr.sun_path[0] = 0;
- memcpy(addr.sun_path + 1, name, namelen);
+ // This is used for abstract socket namespace, we need
+ // an initial '\0' at the start of the Unix socket path.
+ //
+ // Note: The path in this case is *not* supposed to be
+ // '\0'-terminated. ("man 7 unix" for the gory details.)
+ memset(&addr, 0, sizeof(addr));
+ addr.sun_family = AF_LOCAL;
+ addr.sun_path[0] = 0;
+ memcpy(addr.sun_path + 1, name, namelen);
- socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;
+ socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;
- int s = socket(AF_LOCAL, type, 0);
- if (s == -1) {
- return -1;
- }
+ int s = socket(AF_LOCAL, type, 0);
+ if (s == -1) {
+ return -1;
+ }
- int rc = TEMP_FAILURE_RETRY(connect(s, reinterpret_cast<sockaddr*>(&addr), alen));
- if (rc == -1) {
- close(s);
- return -1;
- }
+ int rc = TEMP_FAILURE_RETRY(connect(s, reinterpret_cast<sockaddr*>(&addr), alen));
+ if (rc == -1) {
+ close(s);
+ return -1;
+ }
- return s;
+ return s;
}
/*
@@ -115,65 +115,88 @@
* could allocate memory or hold a lock.
*/
static void log_signal_summary(int signum, const siginfo_t* info) {
- const char* signal_name;
- switch (signum) {
- case SIGILL: signal_name = "SIGILL"; break;
- case SIGABRT: signal_name = "SIGABRT"; break;
- case SIGBUS: signal_name = "SIGBUS"; break;
- case SIGFPE: signal_name = "SIGFPE"; break;
- case SIGSEGV: signal_name = "SIGSEGV"; break;
+ const char* signal_name = "???";
+ bool has_address = false;
+ switch (signum) {
+ case SIGILL:
+ signal_name = "SIGILL";
+ has_address = true;
+ break;
+ case SIGABRT:
+ signal_name = "SIGABRT";
+ break;
+ case SIGBUS:
+ signal_name = "SIGBUS";
+ has_address = true;
+ break;
+ case SIGFPE:
+ signal_name = "SIGFPE";
+ has_address = true;
+ break;
+ case SIGSEGV:
+ signal_name = "SIGSEGV";
+ has_address = true;
+ break;
#if defined(SIGSTKFLT)
- case SIGSTKFLT: signal_name = "SIGSTKFLT"; break;
+ case SIGSTKFLT:
+ signal_name = "SIGSTKFLT";
+ break;
#endif
- case SIGPIPE: signal_name = "SIGPIPE"; break;
- default: signal_name = "???"; break;
- }
+ case SIGPIPE:
+ signal_name = "SIGPIPE";
+ break;
+ }
- char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination
- if (prctl(PR_GET_NAME, (unsigned long)thread_name, 0, 0, 0) != 0) {
- strcpy(thread_name, "<name unknown>");
- } else {
- // short names are null terminated by prctl, but the man page
- // implies that 16 byte names are not.
- thread_name[MAX_TASK_NAME_LEN] = 0;
- }
+ char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination
+ if (prctl(PR_GET_NAME, (unsigned long)thread_name, 0, 0, 0) != 0) {
+ strcpy(thread_name, "<name unknown>");
+ } else {
+ // short names are null terminated by prctl, but the man page
+ // implies that 16 byte names are not.
+ thread_name[MAX_TASK_NAME_LEN] = 0;
+ }
- // "info" will be NULL if the siginfo_t information was not available.
- if (info != NULL) {
- __libc_format_log(ANDROID_LOG_FATAL, "libc",
- "Fatal signal %d (%s) at %p (code=%d), thread %d (%s)",
- signum, signal_name, info->si_addr, info->si_code,
- gettid(), thread_name);
- } else {
- __libc_format_log(ANDROID_LOG_FATAL, "libc",
- "Fatal signal %d (%s), thread %d (%s)",
- signum, signal_name, gettid(), thread_name);
+ // "info" will be NULL if the siginfo_t information was not available.
+ // Many signals don't have an address or a code.
+ char code_desc[32]; // ", code -6"
+ char addr_desc[32]; // ", fault addr 0x1234"
+ addr_desc[0] = code_desc[0] = 0;
+ if (info != NULL) {
+ // For a rethrown signal, this si_code will be right and the one debuggerd shows will
+ // always be SI_TKILL.
+ snprintf(code_desc, sizeof(code_desc), ", code %d", info->si_code);
+ if (has_address) {
+ snprintf(addr_desc, sizeof(addr_desc), ", fault addr %p", info->si_addr);
}
+ }
+ __libc_format_log(ANDROID_LOG_FATAL, "libc",
+ "Fatal signal %d (%s)%s%s in tid %d (%s)",
+ signum, signal_name, code_desc, addr_desc, gettid(), thread_name);
}
/*
* Returns true if the handler for signal "signum" has SA_SIGINFO set.
*/
static bool have_siginfo(int signum) {
- struct sigaction old_action, new_action;
+ struct sigaction old_action, new_action;
- memset(&new_action, 0, sizeof(new_action));
- new_action.sa_handler = SIG_DFL;
- new_action.sa_flags = SA_RESTART;
- sigemptyset(&new_action.sa_mask);
+ memset(&new_action, 0, sizeof(new_action));
+ new_action.sa_handler = SIG_DFL;
+ new_action.sa_flags = SA_RESTART;
+ sigemptyset(&new_action.sa_mask);
- if (sigaction(signum, &new_action, &old_action) < 0) {
- __libc_format_log(ANDROID_LOG_WARN, "libc", "Failed testing for SA_SIGINFO: %s",
- strerror(errno));
- return false;
- }
- bool result = (old_action.sa_flags & SA_SIGINFO) != 0;
+ if (sigaction(signum, &new_action, &old_action) < 0) {
+ __libc_format_log(ANDROID_LOG_WARN, "libc", "Failed testing for SA_SIGINFO: %s",
+ strerror(errno));
+ return false;
+ }
+ bool result = (old_action.sa_flags & SA_SIGINFO) != 0;
- if (sigaction(signum, &old_action, NULL) == -1) {
- __libc_format_log(ANDROID_LOG_WARN, "libc", "Restore failed in test for SA_SIGINFO: %s",
- strerror(errno));
- }
- return result;
+ if (sigaction(signum, &old_action, NULL) == -1) {
+ __libc_format_log(ANDROID_LOG_WARN, "libc", "Restore failed in test for SA_SIGINFO: %s",
+ strerror(errno));
+ }
+ return result;
}
/*
@@ -181,87 +204,87 @@
* we crash.
*/
void debuggerd_signal_handler(int signal_number, siginfo_t* info, void*) {
- // It's possible somebody cleared the SA_SIGINFO flag, which would mean
- // our "info" arg holds an undefined value.
- if (!have_siginfo(signal_number)) {
- info = NULL;
+ // It's possible somebody cleared the SA_SIGINFO flag, which would mean
+ // our "info" arg holds an undefined value.
+ if (!have_siginfo(signal_number)) {
+ info = NULL;
+ }
+
+ log_signal_summary(signal_number, info);
+
+ int s = socket_abstract_client(DEBUGGER_SOCKET_NAME, SOCK_STREAM);
+ if (s != -1) {
+ // debuggerd knows our pid from the credentials on the
+ // local socket but we need to tell it the tid of the crashing thread.
+ // debuggerd will be paranoid and verify that we sent a tid
+ // that's actually in our process.
+ debugger_msg_t msg;
+ msg.action = DEBUGGER_ACTION_CRASH;
+ msg.tid = gettid();
+ msg.abort_msg_address = reinterpret_cast<uintptr_t>(gAbortMessage);
+ int ret = TEMP_FAILURE_RETRY(write(s, &msg, sizeof(msg)));
+ if (ret == sizeof(msg)) {
+ // If the write failed, there is no point trying to read a response.
+ char debuggerd_ack;
+ ret = TEMP_FAILURE_RETRY(read(s, &debuggerd_ack, 1));
+ int saved_errno = errno;
+ notify_gdb_of_libraries();
+ errno = saved_errno;
}
- log_signal_summary(signal_number, info);
-
- int s = socket_abstract_client(DEBUGGER_SOCKET_NAME, SOCK_STREAM);
- if (s != -1) {
- // debuggerd knows our pid from the credentials on the
- // local socket but we need to tell it the tid of the crashing thread.
- // debuggerd will be paranoid and verify that we sent a tid
- // that's actually in our process.
- debugger_msg_t msg;
- msg.action = DEBUGGER_ACTION_CRASH;
- msg.tid = gettid();
- msg.abort_msg_address = reinterpret_cast<uintptr_t>(gAbortMessage);
- int ret = TEMP_FAILURE_RETRY(write(s, &msg, sizeof(msg)));
- if (ret == sizeof(msg)) {
- // If the write failed, there is no point trying to read a response.
- char debuggerd_ack;
- ret = TEMP_FAILURE_RETRY(read(s, &debuggerd_ack, 1));
- int saved_errno = errno;
- notify_gdb_of_libraries();
- errno = saved_errno;
- }
-
- if (ret < 0) {
- // read or write failed -- broken connection?
- __libc_format_log(ANDROID_LOG_FATAL, "libc", "Failed while talking to debuggerd: %s",
- strerror(errno));
- }
-
- close(s);
- } else {
- // socket failed; maybe process ran out of fds?
- __libc_format_log(ANDROID_LOG_FATAL, "libc", "Unable to open connection to debuggerd: %s",
- strerror(errno));
+ if (ret < 0) {
+ // read or write failed -- broken connection?
+ __libc_format_log(ANDROID_LOG_FATAL, "libc", "Failed while talking to debuggerd: %s",
+ strerror(errno));
}
- // Remove our net so we fault for real when we return.
- signal(signal_number, SIG_DFL);
+ close(s);
+ } else {
+ // socket failed; maybe process ran out of fds?
+ __libc_format_log(ANDROID_LOG_FATAL, "libc", "Unable to open connection to debuggerd: %s",
+ strerror(errno));
+ }
- // These signals are not re-thrown when we resume. This means that
- // crashing due to (say) SIGPIPE doesn't work the way you'd expect it
- // to. We work around this by throwing them manually. We don't want
- // to do this for *all* signals because it'll screw up the address for
- // faults like SIGSEGV.
- switch (signal_number) {
- case SIGABRT:
- case SIGFPE:
- case SIGPIPE:
+ // Remove our net so we fault for real when we return.
+ signal(signal_number, SIG_DFL);
+
+ // These signals are not re-thrown when we resume. This means that
+ // crashing due to (say) SIGPIPE doesn't work the way you'd expect it
+ // to. We work around this by throwing them manually. We don't want
+ // to do this for *all* signals because it'll screw up the address for
+ // faults like SIGSEGV.
+ switch (signal_number) {
+ case SIGABRT:
+ case SIGFPE:
+ case SIGPIPE:
#if defined(SIGSTKFLT)
- case SIGSTKFLT:
+ case SIGSTKFLT:
#endif
- tgkill(getpid(), gettid(), signal_number);
- break;
- default: // SIGILL, SIGBUS, SIGSEGV
- break;
- }
+ tgkill(getpid(), gettid(), signal_number);
+ break;
+ default: // SIGILL, SIGBUS, SIGSEGV
+ break;
+ }
}
void debuggerd_init() {
- struct sigaction action;
- memset(&action, 0, sizeof(action));
- sigemptyset(&action.sa_mask);
- action.sa_sigaction = debuggerd_signal_handler;
- action.sa_flags = SA_RESTART | SA_SIGINFO;
+ struct sigaction action;
+ memset(&action, 0, sizeof(action));
+ sigemptyset(&action.sa_mask);
+ action.sa_sigaction = debuggerd_signal_handler;
+ action.sa_flags = SA_RESTART | SA_SIGINFO;
- // Use the alternate signal stack if available so we can catch stack overflows.
- action.sa_flags |= SA_ONSTACK;
+ // Use the alternate signal stack if available so we can catch stack overflows.
+ action.sa_flags |= SA_ONSTACK;
- sigaction(SIGABRT, &action, NULL);
- sigaction(SIGBUS, &action, NULL);
- sigaction(SIGFPE, &action, NULL);
- sigaction(SIGILL, &action, NULL);
- sigaction(SIGPIPE, &action, NULL);
- sigaction(SIGSEGV, &action, NULL);
+ sigaction(SIGABRT, &action, NULL);
+ sigaction(SIGBUS, &action, NULL);
+ sigaction(SIGFPE, &action, NULL);
+ sigaction(SIGILL, &action, NULL);
+ sigaction(SIGPIPE, &action, NULL);
+ sigaction(SIGSEGV, &action, NULL);
#if defined(SIGSTKFLT)
- sigaction(SIGSTKFLT, &action, NULL);
+ sigaction(SIGSTKFLT, &action, NULL);
#endif
- sigaction(SIGTRAP, &action, NULL);
+ sigaction(SIGTRAP, &action, NULL);
}