diff options
Diffstat (limited to 'osdep/subprocess-posix.c')
| -rw-r--r-- | osdep/subprocess-posix.c | 69 |
1 files changed, 62 insertions, 7 deletions
diff --git a/osdep/subprocess-posix.c b/osdep/subprocess-posix.c index e7af4663ea..c75d267cdd 100644 --- a/osdep/subprocess-posix.c +++ b/osdep/subprocess-posix.c @@ -16,7 +16,6 @@ */ #include <poll.h> -#include <pthread.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> @@ -33,6 +32,12 @@ extern char **environ; +#ifdef SIGRTMAX +#define SIGNAL_MAX SIGRTMAX +#else +#define SIGNAL_MAX 32 +#endif + #define SAFE_CLOSE(fd) do { if ((fd) >= 0) close((fd)); (fd) = -1; } while (0) // Async-signal-safe execvpe(). POSIX does not list it as async-signal-safe @@ -65,6 +70,20 @@ static int as_execvpe(const char *path, const char *file, char *const argv[], return -1; } +// In the child process, resets the signal mask to defaults. Also clears any +// signal handlers first so nothing funny happens. +static void reset_signals_child(void) +{ + struct sigaction sa = { 0 }; + sigset_t sigmask; + sa.sa_handler = SIG_DFL; + sigemptyset(&sigmask); + + for (int nr = 1; nr < SIGNAL_MAX; nr++) + sigaction(nr, &sa, NULL); + sigprocmask(SIG_SETMASK, &sigmask, NULL); +} + // Returns 0 on any error, valid PID on success. // This function must be async-signal-safe, as it may be called from a fork(). static pid_t spawn_process(const char *path, struct mp_subprocess_opts *opts, @@ -96,6 +115,7 @@ static pid_t spawn_process(const char *path, struct mp_subprocess_opts *opts, } if (fres == 0) { // child + reset_signals_child(); for (int n = 0; n < opts->num_fds; n++) { if (src_fds[n] == opts->fds[n].fd) { @@ -113,7 +133,7 @@ static pid_t spawn_process(const char *path, struct mp_subprocess_opts *opts, as_execvpe(path, opts->exe, opts->args, opts->env ? opts->env : environ); child_failed: - write(p[1], &(char){1}, 1); // shouldn't be able to fail + (void)write(p[1], &(char){1}, 1); // shouldn't be able to fail _exit(1); } @@ -165,8 +185,21 @@ void mp_subprocess2(struct mp_subprocess_opts *opts, } for (int n = 0; n < opts->num_fds; n++) { + assert(!(opts->fds[n].on_read && opts->fds[n].on_write)); + if (opts->fds[n].on_read && mp_make_cloexec_pipe(comm_pipe[n]) < 0) goto done; + + if (opts->fds[n].on_write || opts->fds[n].write_buf) { + assert(opts->fds[n].on_write && opts->fds[n].write_buf); + if (mp_make_cloexec_pipe(comm_pipe[n]) < 0) + goto done; + MPSWAP(int, comm_pipe[n][0], comm_pipe[n][1]); + + struct sigaction sa = {.sa_handler = SIG_IGN, .sa_flags = SA_RESTART}; + sigfillset(&sa.sa_mask); + sigaction(SIGPIPE, &sa, NULL); + } } devnull = open("/dev/null", O_RDONLY | O_CLOEXEC); @@ -225,7 +258,7 @@ void mp_subprocess2(struct mp_subprocess_opts *opts, if (comm_pipe[n][0] >= 0) { map_fds[num_fds] = n; fds[num_fds++] = (struct pollfd){ - .events = POLLIN, + .events = opts->fds[n].on_read ? POLLIN : POLLOUT, .fd = comm_pipe[n][0], }; } @@ -248,21 +281,43 @@ void mp_subprocess2(struct mp_subprocess_opts *opts, if (pid) kill(pid, SIGKILL); killed_by_us = true; - break; - } else { + goto break_poll; + } + struct mp_subprocess_fd *fd = &opts->fds[n]; + if (fd->on_read) { char buf[4096]; ssize_t r = read(comm_pipe[n][0], buf, sizeof(buf)); if (r < 0 && errno == EINTR) continue; - if (r > 0 && opts->fds[n].on_read) - opts->fds[n].on_read(opts->fds[n].on_read_ctx, buf, r); + fd->on_read(fd->on_read_ctx, buf, MPMAX(r, 0)); if (r <= 0) SAFE_CLOSE(comm_pipe[n][0]); + } else if (fd->on_write) { + if (!fd->write_buf->len) { + fd->on_write(fd->on_write_ctx); + if (!fd->write_buf->len) { + SAFE_CLOSE(comm_pipe[n][0]); + continue; + } + } + ssize_t r = write(comm_pipe[n][0], fd->write_buf->start, + fd->write_buf->len); + if (r < 0 && errno == EINTR) + continue; + if (r < 0) { + // Let's not signal an error for now - caller can check + // whether all buffer was written. + SAFE_CLOSE(comm_pipe[n][0]); + continue; + } + *fd->write_buf = bstr_cut(*fd->write_buf, r); } } } } +break_poll: + // Note: it can happen that a child process closes the pipe, but does not // terminate yet. In this case, we would have to run waitpid() in // a separate thread and use pthread_cancel(), or use other weird |