diff options
Diffstat (limited to 'linker/debugger.cpp')
| -rw-r--r-- | linker/debugger.cpp | 385 |
1 files changed, 213 insertions, 172 deletions
diff --git a/linker/debugger.cpp b/linker/debugger.cpp index 92e9dac..c316151 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> @@ -40,15 +41,19 @@ extern "C" int tgkill(int tgid, int tid, int sig); +#if __LP64__ +#define DEBUGGER_SOCKET_NAME "android:debuggerd64" +#else #define DEBUGGER_SOCKET_NAME "android:debuggerd" +#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 */ @@ -59,46 +64,48 @@ struct debugger_msg_t { // version 2 added: uintptr_t abort_msg_address; + + // version 3 added: + int32_t original_si_code; }; // see man(2) prctl, specifically the section about PR_GET_NAME #define MAX_TASK_NAME_LEN (16) static int socket_abstract_client(const char* name, int type) { - 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; - } - - /* 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; - - int s = socket(AF_LOCAL, type, 0); - if (s == -1) { - return -1; - } - - int err = TEMP_FAILURE_RETRY(connect(s, reinterpret_cast<sockaddr*>(&addr), alen)); - if (err == -1) { - close(s); - s = -1; - } - - return s; + 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; + } + + // 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; + + 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; + } + + return s; } /* @@ -111,158 +118,192 @@ static int socket_abstract_client(const char* name, int type) { * 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 SIGABRT: + signal_name = "SIGABRT"; + break; + case SIGBUS: + signal_name = "SIGBUS"; + has_address = true; + break; + case SIGFPE: + signal_name = "SIGFPE"; + has_address = true; + break; + case SIGILL: + signal_name = "SIGILL"; + has_address = true; + break; + case SIGPIPE: + signal_name = "SIGPIPE"; + 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; - } - - 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); + case SIGTRAP: + signal_name = "SIGTRAP"; + 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; + } + + // "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. + __libc_format_buffer(code_desc, sizeof(code_desc), ", code %d", info->si_code); + if (has_address) { + __libc_format_buffer(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; - - 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; + 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); + + 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; +static void send_debuggerd_packet(siginfo_t* info) { + if (prctl(PR_GET_DUMPABLE, 0, 0, 0, 0) == 0) { + // process has disabled core dumps and PTRACE_ATTACH, and does not want to be dumped. + // Honor that intention by not connecting to debuggerd and asking it + // to dump our internal state. + __libc_format_log(ANDROID_LOG_INFO, "libc", + "Suppressing debuggerd output because prctl(PR_GET_DUMPABLE)==0"); + return; + } + + int s = socket_abstract_client(DEBUGGER_SOCKET_NAME, SOCK_STREAM); + if (s == -1) { + __libc_format_log(ANDROID_LOG_FATAL, "libc", "Unable to open connection to debuggerd: %s", + strerror(errno)); + return; + } + + // 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>(g_abort_message); + msg.original_si_code = (info != NULL) ? info->si_code : 0; + int ret = TEMP_FAILURE_RETRY(write(s, &msg, sizeof(msg))); + if (ret == sizeof(msg)) { + char debuggerd_ack; + ret = TEMP_FAILURE_RETRY(read(s, &debuggerd_ack, 1)); + int saved_errno = errno; + notify_gdb_of_libraries(); + errno = saved_errno; + } else { + // read or write failed -- broken connection? + __libc_format_log(ANDROID_LOG_FATAL, "libc", "Failed while talking to debuggerd: %s", + strerror(errno)); + } + + close(s); } /* * Catches fatal signals so we can ask debuggerd to ptrace us before * we crash. */ -void debuggerd_signal_handler(int n, 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(n)) { - info = NULL; - } - - log_signal_summary(n, info); - - pid_t tid = gettid(); - int s = socket_abstract_client(DEBUGGER_SOCKET_NAME, SOCK_STREAM); - - if (s >= 0) { - // 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 = tid; - 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. - ret = TEMP_FAILURE_RETRY(read(s, &tid, 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)); - } - - /* remove our net so we fault for real when we return */ - signal(n, 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 (n) { - case SIGABRT: - case SIGFPE: - case SIGPIPE: +static 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; + } + + log_signal_summary(signal_number, info); + + send_debuggerd_packet(info); + + // 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 si_addr for + // faults like SIGSEGV. It does screw up the si_code, which is why we + // passed that to debuggerd above. + switch (signal_number) { + case SIGABRT: + case SIGFPE: + case SIGPIPE: #if defined(SIGSTKFLT) - case SIGSTKFLT: + case SIGSTKFLT: #endif - (void) tgkill(getpid(), gettid(), n); - break; - default: // SIGILL, SIGBUS, SIGSEGV - break; - } + case SIGTRAP: + 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; - - // 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); +__LIBC_HIDDEN__ 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; + + // 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); #if defined(SIGSTKFLT) - sigaction(SIGSTKFLT, &action, NULL); + sigaction(SIGSTKFLT, &action, NULL); #endif - sigaction(SIGTRAP, &action, NULL); + sigaction(SIGTRAP, &action, NULL); } |