diff options
| -rw-r--r-- | run-command.c | 121 |
1 files changed, 89 insertions, 32 deletions
diff --git a/run-command.c b/run-command.c index b3a35dd..1f15714 100644 --- a/run-command.c +++ b/run-command.c @@ -211,14 +211,82 @@ static const char **prepare_shell_cmd(struct argv_array *out, const char **argv) #ifndef GIT_WINDOWS_NATIVE static int child_notifier = -1; -static void notify_parent(void) +enum child_errcode { + CHILD_ERR_CHDIR, + CHILD_ERR_ENOENT, + CHILD_ERR_SILENT, + CHILD_ERR_ERRNO +}; + +struct child_err { + enum child_errcode err; + int syserr; /* errno */ +}; + +static void child_die(enum child_errcode err) { - /* - * execvp failed. If possible, we'd like to let start_command - * know, so failures like ENOENT can be handled right away; but - * otherwise, finish_command will still report the error. - */ - xwrite(child_notifier, "", 1); + struct child_err buf; + + buf.err = err; + buf.syserr = errno; + + /* write(2) on buf smaller than PIPE_BUF (min 512) is atomic: */ + xwrite(child_notifier, &buf, sizeof(buf)); + _exit(1); +} + +/* + * parent will make it look like the child spewed a fatal error and died + * this is needed to prevent changes to t0061. + */ +static void fake_fatal(const char *err, va_list params) +{ + vreportf("fatal: ", err, params); +} + +static void child_error_fn(const char *err, va_list params) +{ + const char msg[] = "error() should not be called in child\n"; + xwrite(2, msg, sizeof(msg) - 1); +} + +static void child_warn_fn(const char *err, va_list params) +{ + const char msg[] = "warn() should not be called in child\n"; + xwrite(2, msg, sizeof(msg) - 1); +} + +static void NORETURN child_die_fn(const char *err, va_list params) +{ + const char msg[] = "die() should not be called in child\n"; + xwrite(2, msg, sizeof(msg) - 1); + _exit(2); +} + +/* this runs in the parent process */ +static void child_err_spew(struct child_process *cmd, struct child_err *cerr) +{ + static void (*old_errfn)(const char *err, va_list params); + + old_errfn = get_error_routine(); + set_error_routine(fake_fatal); + errno = cerr->syserr; + + switch (cerr->err) { + case CHILD_ERR_CHDIR: + error_errno("exec '%s': cd to '%s' failed", + cmd->argv[0], cmd->dir); + break; + case CHILD_ERR_ENOENT: + error_errno("cannot run %s", cmd->argv[0]); + break; + case CHILD_ERR_SILENT: + break; + case CHILD_ERR_ERRNO: + error_errno("cannot exec '%s'", cmd->argv[0]); + break; + } + set_error_routine(old_errfn); } static void prepare_cmd(struct argv_array *out, const struct child_process *cmd) @@ -341,13 +409,6 @@ static int wait_or_whine(pid_t pid, const char *argv0, int in_signal) code += 128; } else if (WIFEXITED(status)) { code = WEXITSTATUS(status); - /* - * Convert special exit code when execvp failed. - */ - if (code == 127) { - code = -1; - failed_errno = ENOENT; - } } else { error("waitpid is confused (%s)", argv0); } @@ -435,6 +496,7 @@ fail_pipe: int null_fd = -1; char **childenv; struct argv_array argv = ARGV_ARRAY_INIT; + struct child_err cerr; if (pipe(notify_pipe)) notify_pipe[0] = notify_pipe[1] = -1; @@ -453,20 +515,16 @@ fail_pipe: failed_errno = errno; if (!cmd->pid) { /* - * Redirect the channel to write syscall error messages to - * before redirecting the process's stderr so that all die() - * in subsequent call paths use the parent's stderr. + * Ensure the default die/error/warn routines do not get + * called, they can take stdio locks and malloc. */ - if (cmd->no_stderr || need_err) { - int child_err = dup(2); - set_cloexec(child_err); - set_error_handle(fdopen(child_err, "w")); - } + set_die_routine(child_die_fn); + set_error_routine(child_error_fn); + set_warn_routine(child_warn_fn); close(notify_pipe[0]); set_cloexec(notify_pipe[1]); child_notifier = notify_pipe[1]; - atexit(notify_parent); if (cmd->no_stdin) dup2(null_fd, 0); @@ -501,8 +559,7 @@ fail_pipe: } if (cmd->dir && chdir(cmd->dir)) - die_errno("exec '%s': cd to '%s' failed", cmd->argv[0], - cmd->dir); + child_die(CHILD_ERR_CHDIR); /* * Attempt to exec using the command and arguments starting at @@ -517,12 +574,11 @@ fail_pipe: (char *const *) childenv); if (errno == ENOENT) { - if (!cmd->silent_exec_failure) - error("cannot run %s: %s", cmd->argv[0], - strerror(ENOENT)); - exit(127); + if (cmd->silent_exec_failure) + child_die(CHILD_ERR_SILENT); + child_die(CHILD_ERR_ENOENT); } else { - die_errno("cannot exec '%s'", cmd->argv[0]); + child_die(CHILD_ERR_ERRNO); } } if (cmd->pid < 0) @@ -533,17 +589,18 @@ fail_pipe: /* * Wait for child's exec. If the exec succeeds (or if fork() * failed), EOF is seen immediately by the parent. Otherwise, the - * child process sends a single byte. + * child process sends a child_err struct. * Note that use of this infrastructure is completely advisory, * therefore, we keep error checks minimal. */ close(notify_pipe[1]); - if (read(notify_pipe[0], ¬ify_pipe[1], 1) == 1) { + if (xread(notify_pipe[0], &cerr, sizeof(cerr)) == sizeof(cerr)) { /* * At this point we know that fork() succeeded, but exec() * failed. Errors have been reported to our stderr. */ wait_or_whine(cmd->pid, cmd->argv[0], 0); + child_err_spew(cmd, &cerr); failed_errno = errno; cmd->pid = -1; } |