diff options
Diffstat (limited to 'src/callproc.c')
| -rw-r--r-- | src/callproc.c | 191 |
1 files changed, 190 insertions, 1 deletions
diff --git a/src/callproc.c b/src/callproc.c index fa43f973844..c949fff4db9 100644 --- a/src/callproc.c +++ b/src/callproc.c @@ -28,6 +28,20 @@ along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. */ #include <sys/file.h> #include <fcntl.h> +/* In order to be able to use `posix_spawn', it needs to support some + variant of `chdir' as well as `setsid'. */ +#if defined HAVE_SPAWN_H && defined HAVE_POSIX_SPAWN \ + && defined HAVE_POSIX_SPAWNATTR_SETFLAGS \ + && (defined HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR \ + || defined HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR_NP) \ + && defined HAVE_DECL_POSIX_SPAWN_SETSID \ + && HAVE_DECL_POSIX_SPAWN_SETSID == 1 +# include <spawn.h> +# define USABLE_POSIX_SPAWN 1 +#else +# define USABLE_POSIX_SPAWN 0 +#endif + #include "lisp.h" #ifdef SETUP_SLAVE_PTY @@ -1247,6 +1261,130 @@ child_setup (int in, int out, int err, char **new_argv, char **env, #endif /* not WINDOWSNT */ } +#if USABLE_POSIX_SPAWN + +/* Set up ACTIONS and ATTRIBUTES for `posix_spawn'. Return an error + number. */ + +static int +emacs_posix_spawn_init_actions (posix_spawn_file_actions_t *actions, + int std_in, int std_out, int std_err, + const char *cwd) +{ + int error = posix_spawn_file_actions_init (actions); + if (error != 0) + return error; + + error = posix_spawn_file_actions_adddup2 (actions, std_in, + STDIN_FILENO); + if (error != 0) + goto out; + + error = posix_spawn_file_actions_adddup2 (actions, std_out, + STDOUT_FILENO); + if (error != 0) + goto out; + + error = posix_spawn_file_actions_adddup2 (actions, + std_err < 0 ? std_out + : std_err, + STDERR_FILENO); + if (error != 0) + goto out; + + error = +#ifdef HAVE_POSIX_SPAWN_FILE_ACTIONS_ADDCHDIR + posix_spawn_file_actions_addchdir +#else + posix_spawn_file_actions_addchdir_np +#endif + (actions, cwd); + if (error != 0) + goto out; + + out: + if (error != 0) + posix_spawn_file_actions_destroy (actions); + return error; +} + +static int +emacs_posix_spawn_init_attributes (posix_spawnattr_t *attributes) +{ + int error = posix_spawnattr_init (attributes); + if (error != 0) + return error; + + error = posix_spawnattr_setflags (attributes, + POSIX_SPAWN_SETSID + | POSIX_SPAWN_SETSIGDEF + | POSIX_SPAWN_SETSIGMASK); + if (error != 0) + goto out; + + sigset_t sigdefault; + sigemptyset (&sigdefault); + +#ifdef DARWIN_OS + /* Work around a macOS bug, where SIGCHLD is apparently + delivered to a vforked child instead of to its parent. See: + https://lists.gnu.org/r/emacs-devel/2017-05/msg00342.html + */ + sigaddset (&sigdefault, SIGCHLD); +#endif + + sigaddset (&sigdefault, SIGINT); + sigaddset (&sigdefault, SIGQUIT); +#ifdef SIGPROF + sigaddset (&sigdefault, SIGPROF); +#endif + + /* Emacs ignores SIGPIPE, but the child should not. */ + sigaddset (&sigdefault, SIGPIPE); + /* Likewise for SIGPROF. */ +#ifdef SIGPROF + sigaddset (&sigdefault, SIGPROF); +#endif + + error = posix_spawnattr_setsigdefault (attributes, &sigdefault); + if (error != 0) + goto out; + + /* Stop blocking SIGCHLD in the child. */ + sigset_t oldset; + error = pthread_sigmask (SIG_SETMASK, NULL, &oldset); + if (error != 0) + goto out; + error = posix_spawnattr_setsigmask (attributes, &oldset); + if (error != 0) + goto out; + + out: + if (error != 0) + posix_spawnattr_destroy (attributes); + + return error; +} + +static int +emacs_posix_spawn_init (posix_spawn_file_actions_t *actions, + posix_spawnattr_t *attributes, int std_in, + int std_out, int std_err, const char *cwd) +{ + int error = emacs_posix_spawn_init_actions (actions, std_in, + std_out, std_err, cwd); + if (error != 0) + return error; + + error = emacs_posix_spawn_init_attributes (attributes); + if (error != 0) + return error; + + return 0; +} + +#endif + /* Start a new asynchronous subprocess. If successful, return zero and store the process identifier of the new process in *NEWPID. Use STDIN, STDOUT, and STDERR as standard streams for the new @@ -1266,10 +1404,58 @@ emacs_spawn (pid_t *newpid, int std_in, int std_out, int std_err, char **argv, char **envp, const char *cwd, const char *pty, const sigset_t *oldset) { +#if USABLE_POSIX_SPAWN + /* Prefer the simpler `posix_spawn' if available. `posix_spawn' + doesn't yet support setting up pseudoterminals, so we fall back + to `vfork' if we're supposed to use a pseudoterminal. */ + + bool use_posix_spawn = pty == NULL; + + posix_spawn_file_actions_t actions; + posix_spawnattr_t attributes; + + if (use_posix_spawn) + { + /* Initialize optional attributes before blocking. */ + int error + = emacs_posix_spawn_init (&actions, &attributes, std_in, + std_out, std_err, cwd); + if (error != 0) + return error; + } +#endif + int pid; + int vfork_error; eassert (input_blocked_p ()); +#if USABLE_POSIX_SPAWN + if (use_posix_spawn) + { + vfork_error = posix_spawn (&pid, argv[0], &actions, &attributes, + argv, envp); + if (vfork_error != 0) + pid = -1; + + int error = posix_spawn_file_actions_destroy (&actions); + if (error != 0) + { + errno = error; + emacs_perror ("posix_spawn_file_actions_destroy"); + } + + error = posix_spawnattr_destroy (&attributes); + if (error != 0) + { + errno = error; + emacs_perror ("posix_spawnattr_destroy"); + } + + goto fork_done; + } +#endif + #ifndef WINDOWSNT /* vfork, and prevent local vars from being clobbered by the vfork. */ pid_t *volatile newpid_volatile = newpid; @@ -1413,8 +1599,11 @@ emacs_spawn (pid_t *newpid, int std_in, int std_out, int std_err, /* Back in the parent process. */ - int vfork_error = pid < 0 ? errno : 0; + vfork_error = pid < 0 ? errno : 0; +#if USABLE_POSIX_SPAWN + fork_done: +#endif if (pid < 0) { eassert (0 < vfork_error); |