diff options
Diffstat (limited to 'src/callproc.c')
| -rw-r--r-- | src/callproc.c | 270 |
1 files changed, 193 insertions, 77 deletions
diff --git a/src/callproc.c b/src/callproc.c index c7f560ac3da..8603382f0c3 100644 --- a/src/callproc.c +++ b/src/callproc.c @@ -100,6 +100,15 @@ enum }; static Lisp_Object call_process (ptrdiff_t, Lisp_Object *, int, ptrdiff_t); + +#ifdef DOS_NT +# define CHILD_SETUP_TYPE int +#else +# define CHILD_SETUP_TYPE _Noreturn void +#endif + +static CHILD_SETUP_TYPE child_setup (int, int, int, char *const *, + char *const *, const char *); /* Return the current buffer's working directory, or the home directory if it's unreachable, as a string suitable for a system call. @@ -300,8 +309,7 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd, #ifdef MSDOS /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */ char *tempfile = NULL; #else - sigset_t oldset; - pid_t pid; + pid_t pid = -1; #endif int child_errno; int fd_output, fd_error; @@ -588,77 +596,10 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd, #ifndef MSDOS - block_input (); - block_child_signal (&oldset); - -#ifdef WINDOWSNT - pid = child_setup (filefd, fd_output, fd_error, new_argv, env, - SSDATA (current_dir)); -#else /* not WINDOWSNT */ - - /* vfork, and prevent local vars from being clobbered by the vfork. */ - { - Lisp_Object volatile buffer_volatile = buffer; - Lisp_Object volatile coding_systems_volatile = coding_systems; - Lisp_Object volatile current_dir_volatile = current_dir; - bool volatile display_p_volatile = display_p; - int volatile fd_error_volatile = fd_error; - int volatile filefd_volatile = filefd; - ptrdiff_t volatile count_volatile = count; - ptrdiff_t volatile sa_avail_volatile = sa_avail; - ptrdiff_t volatile sa_count_volatile = sa_count; - char **volatile new_argv_volatile = new_argv; - char *const *volatile env_volatile = env; - int volatile callproc_fd_volatile[CALLPROC_FDS]; - for (i = 0; i < CALLPROC_FDS; i++) - callproc_fd_volatile[i] = callproc_fd[i]; - - pid = vfork (); - - buffer = buffer_volatile; - coding_systems = coding_systems_volatile; - current_dir = current_dir_volatile; - display_p = display_p_volatile; - fd_error = fd_error_volatile; - filefd = filefd_volatile; - count = count_volatile; - sa_avail = sa_avail_volatile; - sa_count = sa_count_volatile; - new_argv = new_argv_volatile; - env = env_volatile; - - for (i = 0; i < CALLPROC_FDS; i++) - callproc_fd[i] = callproc_fd_volatile[i]; - fd_output = callproc_fd[CALLPROC_STDOUT]; - } - - if (pid == 0) - { -#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 - */ - signal (SIGCHLD, SIG_DFL); -#endif - - unblock_child_signal (&oldset); - dissociate_controlling_tty (); - - /* Emacs ignores SIGPIPE, but the child should not. */ - signal (SIGPIPE, SIG_DFL); - /* Likewise for SIGPROF. */ -#ifdef SIGPROF - signal (SIGPROF, SIG_DFL); -#endif - - child_setup (filefd, fd_output, fd_error, new_argv, env, - SSDATA (current_dir)); - } - -#endif /* not WINDOWSNT */ - - child_errno = errno; + child_errno + = emacs_spawn (&pid, filefd, fd_output, fd_error, new_argv, env, + SSDATA (current_dir), NULL); + eassert ((child_errno == 0) == (0 < pid)); if (pid > 0) { @@ -678,9 +619,6 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd, } } - unblock_child_signal (&oldset); - unblock_input (); - if (pid < 0) report_file_errno (CHILD_SETUP_ERROR_DESC, Qnil, child_errno); @@ -1221,7 +1159,7 @@ exec_failed (char const *name, int err) On MS-Windows, either return a pid or return -1 and set errno. On MS-DOS, either return an exit status or signal an error. */ -CHILD_SETUP_TYPE +static CHILD_SETUP_TYPE child_setup (int in, int out, int err, char *const *new_argv, char *const *env, const char *current_dir) { @@ -1287,6 +1225,184 @@ child_setup (int in, int out, int err, char *const *new_argv, #endif /* not WINDOWSNT */ } +/* 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 + process. Use ARGV as argument vector for the new process; use + process image file ARGV[0]. Use ENVP for the environment block for + the new process. Use CWD as working directory for the new process. + If PTY is not NULL, it must be a pseudoterminal device. If PTY is + NULL, don't perform any terminal setup. */ + +int +emacs_spawn (pid_t *newpid, int stdin, int stdout, int stderr, + char *const *argv, char *const *envp, const char *cwd, + const char *pty) +{ + sigset_t oldset; + int pid; + + block_input (); + block_child_signal (&oldset); + +#ifndef WINDOWSNT + /* vfork, and prevent local vars from being clobbered by the vfork. */ + pid_t *volatile newpid_volatile = newpid; + const char *volatile cwd_volatile = cwd; + const char *volatile pty_volatile = pty; + char *const *volatile argv_volatile = argv; + int volatile stdin_volatile = stdin; + int volatile stdout_volatile = stdout; + int volatile stderr_volatile = stderr; + char *const *volatile envp_volatile = envp; + +#ifdef DARWIN_OS + /* Darwin doesn't let us run setsid after a vfork, so use fork when + necessary. Below, we reset SIGCHLD handling after a vfork, as + apparently macOS can mistakenly deliver SIGCHLD to the child. */ + if (pty != NULL) + pid = fork (); + else + pid = vfork (); +#else + pid = vfork (); +#endif + + newpid = newpid_volatile; + cwd = cwd_volatile; + pty = pty_volatile; + argv = argv_volatile; + stdin = stdin_volatile; + stdout = stdout_volatile; + stderr = stderr_volatile; + envp = envp_volatile; + + if (pid == 0) +#endif /* not WINDOWSNT */ + { + bool pty_flag = pty != NULL; + /* Make the pty be the controlling terminal of the process. */ +#ifdef HAVE_PTYS + dissociate_controlling_tty (); + + /* Make the pty's terminal the controlling terminal. */ + if (pty_flag && stdin >= 0) + { +#ifdef TIOCSCTTY + /* We ignore the return value + because faith@cs.unc.edu says that is necessary on Linux. */ + ioctl (stdin, TIOCSCTTY, 0); +#endif + } +#if defined (LDISC1) + if (pty_flag && stdin >= 0) + { + struct termios t; + tcgetattr (stdin, &t); + t.c_lflag = LDISC1; + if (tcsetattr (stdin, TCSANOW, &t) < 0) + emacs_perror ("create_process/tcsetattr LDISC1"); + } +#else +#if defined (NTTYDISC) && defined (TIOCSETD) + if (pty_flag && stdin >= 0) + { + /* Use new line discipline. */ + int ldisc = NTTYDISC; + ioctl (stdin, TIOCSETD, &ldisc); + } +#endif +#endif + +#if !defined (DONT_REOPEN_PTY) +/*** There is a suggestion that this ought to be a + conditional on TIOCSPGRP, or !defined TIOCSCTTY. + Trying the latter gave the wrong results on Debian GNU/Linux 1.1; + that system does seem to need this code, even though + both TIOCSCTTY is defined. */ + /* Now close the pty (if we had it open) and reopen it. + This makes the pty the controlling terminal of the subprocess. */ + if (pty_flag) + { + + /* I wonder if emacs_close (emacs_open (pty, ...)) + would work? */ + if (stdin >= 0) + emacs_close (stdin); + stdout = stdin = emacs_open (pty, O_RDWR, 0); + + if (stdin < 0) + { + emacs_perror (pty); + _exit (EXIT_CANCELED); + } + + } +#endif /* not DONT_REOPEN_PTY */ + +#ifdef SETUP_SLAVE_PTY + if (pty_flag) + { + SETUP_SLAVE_PTY; + } +#endif /* SETUP_SLAVE_PTY */ +#endif /* HAVE_PTYS */ + +#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 + */ + signal (SIGCHLD, SIG_DFL); +#endif + + signal (SIGINT, SIG_DFL); + signal (SIGQUIT, SIG_DFL); +#ifdef SIGPROF + signal (SIGPROF, SIG_DFL); +#endif + + /* Emacs ignores SIGPIPE, but the child should not. */ + signal (SIGPIPE, SIG_DFL); + /* Likewise for SIGPROF. */ +#ifdef SIGPROF + signal (SIGPROF, SIG_DFL); +#endif + + /* Stop blocking SIGCHLD in the child. */ + unblock_child_signal (&oldset); + + if (pty_flag) + child_setup_tty (stdout); + + if (stderr < 0) + stderr = stdout; +#ifdef WINDOWSNT + pid = child_setup (stdin, stdout, stderr, argv, envp, cwd); +#else /* not WINDOWSNT */ + child_setup (stdin, stdout, stderr, argv, envp, cwd); +#endif /* not WINDOWSNT */ + } + + /* Back in the parent process. */ + + int vfork_error = pid < 0 ? errno : 0; + + /* Stop blocking in the parent. */ + unblock_child_signal (&oldset); + unblock_input (); + + if (pid < 0) + { + eassert (0 < vfork_error); + return vfork_error; + } + + eassert (0 < pid); + *newpid = pid; + return 0; +} + static bool getenv_internal_1 (const char *var, ptrdiff_t varlen, char **value, ptrdiff_t *valuelen, Lisp_Object env) |