diff options
Diffstat (limited to 'src/common/backtrace.c')
| -rw-r--r-- | src/common/backtrace.c | 104 |
1 files changed, 69 insertions, 35 deletions
diff --git a/src/common/backtrace.c b/src/common/backtrace.c index f2498b2aa6..d83cbba0e8 100644 --- a/src/common/backtrace.c +++ b/src/common/backtrace.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2013-2017, The Tor Project, Inc. */ +/* Copyright (c) 2013-2018, The Tor Project, Inc. */ /* See LICENSE for licensing information */ /** @@ -14,9 +14,7 @@ */ #include "orconfig.h" -#include "compat.h" -#include "util.h" -#include "torlog.h" +#include "common/torerr.h" #ifdef HAVE_EXECINFO_H #include <execinfo.h> @@ -30,6 +28,9 @@ #ifdef HAVE_SIGNAL_H #include <signal.h> #endif +#include <errno.h> +#include <stdlib.h> +#include <string.h> #ifdef HAVE_CYGWIN_SIGNAL_H #include <cygwin/signal.h> @@ -39,8 +40,13 @@ #include <ucontext.h> #endif /* defined(HAVE_CYGWIN_SIGNAL_H) || ... */ +#ifdef HAVE_PTHREAD_H +#include <pthread.h> +#endif + #define EXPOSE_CLEAN_BACKTRACE -#include "backtrace.h" +#include "common/backtrace.h" +#include "common/torerr.h" #if defined(HAVE_EXECINFO_H) && defined(HAVE_BACKTRACE) && \ defined(HAVE_BACKTRACE_SYMBOLS_FD) && defined(HAVE_SIGACTION) @@ -51,17 +57,21 @@ #define NO_BACKTRACE_IMPL #endif -/** Version of Tor to report in backtrace messages. */ -static char *bt_version = NULL; +// Redundant with util.h, but doing it here so we can avoid that dependency. +#define raw_free free #ifdef USE_BACKTRACE +/** Version of Tor to report in backtrace messages. */ +static char bt_version[128] = ""; + /** Largest stack depth to try to dump. */ #define MAX_DEPTH 256 /** Static allocation of stack to dump. This is static so we avoid stack * pressure. */ static void *cb_buf[MAX_DEPTH]; -/** Protects cb_buf from concurrent access */ -static tor_mutex_t cb_buf_mutex; +/** Protects cb_buf from concurrent access. Pthreads, since this code + * is Unix-only, and since this code needs to be lowest-level. */ +static pthread_mutex_t cb_buf_mutex = PTHREAD_MUTEX_INITIALIZER; /** Change a stacktrace in <b>stack</b> of depth <b>depth</b> so that it will * log the correct function from which a signal was received with context @@ -94,33 +104,35 @@ clean_backtrace(void **stack, size_t depth, const ucontext_t *ctx) } /** Log a message <b>msg</b> at <b>severity</b> in <b>domain</b>, and follow - * that with a backtrace log. */ + * that with a backtrace log. Send messages via the tor_log function at + * logger". */ void -log_backtrace(int severity, int domain, const char *msg) +log_backtrace_impl(int severity, int domain, const char *msg, + tor_log_fn logger) { size_t depth; char **symbols; size_t i; - tor_mutex_acquire(&cb_buf_mutex); + pthread_mutex_lock(&cb_buf_mutex); depth = backtrace(cb_buf, MAX_DEPTH); symbols = backtrace_symbols(cb_buf, (int)depth); - tor_log(severity, domain, "%s. Stack trace:", msg); + logger(severity, domain, "%s. Stack trace:", msg); if (!symbols) { /* LCOV_EXCL_START -- we can't provoke this. */ - tor_log(severity, domain, " Unable to generate backtrace."); + logger(severity, domain, " Unable to generate backtrace."); goto done; /* LCOV_EXCL_STOP */ } for (i=0; i < depth; ++i) { - tor_log(severity, domain, " %s", symbols[i]); + logger(severity, domain, " %s", symbols[i]); } raw_free(symbols); done: - tor_mutex_release(&cb_buf_mutex); + pthread_mutex_unlock(&cb_buf_mutex); } static void crash_handler(int sig, siginfo_t *si, void *ctx_) @@ -155,18 +167,34 @@ crash_handler(int sig, siginfo_t *si, void *ctx_) abort(); } +/** Write a backtrace to all of the emergency-error fds. */ +void +dump_stack_symbols_to_error_fds(void) +{ + int n_fds, i; + const int *fds = NULL; + size_t depth; + + depth = backtrace(cb_buf, MAX_DEPTH); + + n_fds = tor_log_get_sigsafe_err_fds(&fds); + for (i=0; i < n_fds; ++i) + backtrace_symbols_fd(cb_buf, (int)depth, fds[i]); +} + /** Install signal handlers as needed so that when we crash, we produce a - * useful stack trace. Return 0 on success, -1 on failure. */ + * useful stack trace. Return 0 on success, -errno on failure. */ static int -install_bt_handler(void) +install_bt_handler(const char *software) { int trap_signals[] = { SIGSEGV, SIGILL, SIGFPE, SIGBUS, SIGSYS, SIGIO, -1 }; int i, rv=0; - struct sigaction sa; + strncpy(bt_version, software, sizeof(bt_version) - 1); + bt_version[sizeof(bt_version) - 1] = 0; - tor_mutex_init(&cb_buf_mutex); + struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_sigaction = crash_handler; @@ -176,8 +204,7 @@ install_bt_handler(void) for (i = 0; trap_signals[i] >= 0; ++i) { if (sigaction(trap_signals[i], &sa, NULL) == -1) { /* LCOV_EXCL_START */ - log_warn(LD_BUG, "Sigaction failed: %s", strerror(errno)); - rv = -1; + rv = -errno; /* LCOV_EXCL_STOP */ } } @@ -200,20 +227,21 @@ install_bt_handler(void) static void remove_bt_handler(void) { - tor_mutex_uninit(&cb_buf_mutex); } #endif /* defined(USE_BACKTRACE) */ #ifdef NO_BACKTRACE_IMPL void -log_backtrace(int severity, int domain, const char *msg) +log_backtrace_impl(int severity, int domain, const char *msg, + tor_log_fn logger) { - tor_log(severity, domain, "%s. (Stack trace not available)", msg); + logger(severity, domain, "%s. (Stack trace not available)", msg); } static int -install_bt_handler(void) +install_bt_handler(const char *software) { + (void) software; return 0; } @@ -221,19 +249,28 @@ static void remove_bt_handler(void) { } + +void +dump_stack_symbols_to_error_fds(void) +{ +} #endif /* defined(NO_BACKTRACE_IMPL) */ /** Set up code to handle generating error messages on crashes. */ int configure_backtrace_handler(const char *tor_version) { - tor_free(bt_version); - if (tor_version) - tor_asprintf(&bt_version, "Tor %s", tor_version); - else - tor_asprintf(&bt_version, "Tor"); + char version[128]; + strncpy(version, "Tor", sizeof(version)-1); + + if (tor_version) { + strncat(version, " ", sizeof(version)-1); + strncat(version, tor_version, sizeof(version)-1); + } - return install_bt_handler(); + version[sizeof(version) - 1] = 0; + + return install_bt_handler(version); } /** Perform end-of-process cleanup for code that generates error messages on @@ -242,7 +279,4 @@ void clean_up_backtrace_handler(void) { remove_bt_handler(); - - tor_free(bt_version); } - |