зеркало из https://github.com/microsoft/git.git
Merge branch 'ti/glibc-stdio-mutex-from-signal-handler' into maint
Allocation related functions and stdio are unsafe things to call inside a signal handler, and indeed killing the pager can cause glibc to deadlock waiting on allocation mutex as our signal handler tries to free() some data structures in wait_for_pager(). Reduce these unsafe calls. * ti/glibc-stdio-mutex-from-signal-handler: pager: don't use unsafe functions in signal handlers
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Коммит
267ebf6c84
22
pager.c
22
pager.c
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@ -14,19 +14,29 @@
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static const char *pager_argv[] = { NULL, NULL };
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static struct child_process pager_process = CHILD_PROCESS_INIT;
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static void wait_for_pager(void)
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static void wait_for_pager(int in_signal)
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{
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fflush(stdout);
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fflush(stderr);
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if (!in_signal) {
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fflush(stdout);
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fflush(stderr);
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}
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/* signal EOF to pager */
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close(1);
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close(2);
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finish_command(&pager_process);
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if (in_signal)
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finish_command_in_signal(&pager_process);
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else
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finish_command(&pager_process);
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}
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static void wait_for_pager_atexit(void)
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{
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wait_for_pager(0);
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}
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static void wait_for_pager_signal(int signo)
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{
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wait_for_pager();
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wait_for_pager(1);
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sigchain_pop(signo);
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raise(signo);
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}
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@ -90,7 +100,7 @@ void setup_pager(void)
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/* this makes sure that the parent terminates after the pager */
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sigchain_push_common(wait_for_pager_signal);
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atexit(wait_for_pager);
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atexit(wait_for_pager_atexit);
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}
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int pager_in_use(void)
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@ -18,26 +18,27 @@ struct child_to_clean {
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static struct child_to_clean *children_to_clean;
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static int installed_child_cleanup_handler;
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static void cleanup_children(int sig)
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static void cleanup_children(int sig, int in_signal)
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{
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while (children_to_clean) {
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struct child_to_clean *p = children_to_clean;
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children_to_clean = p->next;
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kill(p->pid, sig);
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free(p);
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if (!in_signal)
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free(p);
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}
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}
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static void cleanup_children_on_signal(int sig)
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{
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cleanup_children(sig);
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cleanup_children(sig, 1);
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sigchain_pop(sig);
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raise(sig);
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}
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static void cleanup_children_on_exit(void)
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{
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cleanup_children(SIGTERM);
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cleanup_children(SIGTERM, 0);
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}
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static void mark_child_for_cleanup(pid_t pid)
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@ -220,7 +221,7 @@ static inline void set_cloexec(int fd)
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fcntl(fd, F_SETFD, flags | FD_CLOEXEC);
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}
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static int wait_or_whine(pid_t pid, const char *argv0)
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static int wait_or_whine(pid_t pid, const char *argv0, int in_signal)
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{
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int status, code = -1;
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pid_t waiting;
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@ -228,6 +229,8 @@ static int wait_or_whine(pid_t pid, const char *argv0)
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while ((waiting = waitpid(pid, &status, 0)) < 0 && errno == EINTR)
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; /* nothing */
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if (in_signal)
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return 0;
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if (waiting < 0) {
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failed_errno = errno;
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@ -437,7 +440,7 @@ fail_pipe:
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* At this point we know that fork() succeeded, but execvp()
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* failed. Errors have been reported to our stderr.
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*/
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wait_or_whine(cmd->pid, cmd->argv[0]);
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wait_or_whine(cmd->pid, cmd->argv[0], 0);
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failed_errno = errno;
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cmd->pid = -1;
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}
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@ -536,12 +539,18 @@ fail_pipe:
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int finish_command(struct child_process *cmd)
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{
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int ret = wait_or_whine(cmd->pid, cmd->argv[0]);
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int ret = wait_or_whine(cmd->pid, cmd->argv[0], 0);
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argv_array_clear(&cmd->args);
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argv_array_clear(&cmd->env_array);
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return ret;
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}
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int finish_command_in_signal(struct child_process *cmd)
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{
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return wait_or_whine(cmd->pid, cmd->argv[0], 1);
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}
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int run_command(struct child_process *cmd)
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{
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int code;
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@ -772,7 +781,7 @@ error:
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int finish_async(struct async *async)
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{
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#ifdef NO_PTHREADS
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return wait_or_whine(async->pid, "child process");
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return wait_or_whine(async->pid, "child process", 0);
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#else
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void *ret = (void *)(intptr_t)(-1);
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@ -50,6 +50,7 @@ void child_process_init(struct child_process *);
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int start_command(struct child_process *);
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int finish_command(struct child_process *);
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int finish_command_in_signal(struct child_process *);
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int run_command(struct child_process *);
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/*
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