diff options
Diffstat (limited to 'sysdeps/posix/pipestream.c')
| -rw-r--r-- | sysdeps/posix/pipestream.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/sysdeps/posix/pipestream.c b/sysdeps/posix/pipestream.c new file mode 100644 index 0000000..53595f5 --- /dev/null +++ b/sysdeps/posix/pipestream.c @@ -0,0 +1,223 @@ +/* Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <ansidecl.h> +#include <errno.h> +#include <stddef.h> +#include <signal.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <unistd.h> +#include <fcntl.h> + +#define SH_PATH "/bin/sh" /* Shell to run. */ +#define SH_NAME "sh" /* Name to give it. */ + +/* Structure describing a popen child. */ +struct child + { + pid_t pid; /* PID of the child. */ + __ptr_t cookie; /* Original cookie from fdopen. */ + __io_functions funcs; /* Original functions from fdopen. */ + }; + +/* io_functions for pipe streams. + These all simply call the corresponding + original function with the original cookie. */ + +#define FUNC(type, name, args) \ + static type DEFUN(__CONCAT(child_,name), args, __CONCAT(name,decl)) \ + { \ + struct child *c = (struct child *) cookie; \ + { \ + __ptr_t cookie = c->cookie; \ + return (*c->funcs.__CONCAT(__,name)) args; \ + } \ + } + +#define readdecl PTR cookie AND register char *buf AND register size_t n +FUNC (int, read, (cookie, buf, n)) +#define writedecl PTR cookie AND register CONST char *buf AND register size_t n +FUNC (int, write, (cookie, buf, n)) +#define seekdecl PTR cookie AND fpos_t *pos AND int whence +FUNC (int, seek, (cookie, pos, whence)) +#define closedecl PTR cookie +FUNC (int, close, (cookie)) +#define filenodecl PTR cookie +FUNC (int, fileno, (cookie)) + +static const __io_functions child_funcs + = { child_read, child_write, child_seek, child_close, child_fileno }; + +/* Open a new stream that is a one-way pipe to a + child process running the given shell command. */ +FILE * +DEFUN(popen, (command, mode), CONST char *command AND CONST char *mode) +{ + pid_t pid; + int pipedes[2]; + FILE *stream; + struct child *child; + + if (command == NULL || mode == NULL || (*mode != 'r' && *mode != 'w')) + { + errno = EINVAL; + return NULL; + } + + /* Create the pipe. */ + if (pipe(pipedes) < 0) + return NULL; + + /* Fork off the child. */ + pid = __vfork (); + if (pid == (pid_t) -1) + { + /* The fork failed. */ + (void) close (pipedes[0]); + (void) close (pipedes[1]); + return NULL; + } + else if (pid == (pid_t) 0) + { + /* We are the child side. Make the write side of + the pipe be stdin or the read side be stdout. */ + + CONST char *new_argv[4]; + + if ((*mode == 'w' ? dup2(pipedes[STDIN_FILENO], STDIN_FILENO) : + dup2(pipedes[STDOUT_FILENO], STDOUT_FILENO)) < 0) + _exit(127); + + /* Close the pipe descriptors. */ + (void) close(pipedes[STDIN_FILENO]); + (void) close(pipedes[STDOUT_FILENO]); + + /* Exec the shell. */ + new_argv[0] = SH_NAME; + new_argv[1] = "-c"; + new_argv[2] = command; + new_argv[3] = NULL; + (void) execve(SH_PATH, (char *CONST *) new_argv, environ); + /* Die if it failed. */ + _exit(127); + } + + /* We are the parent side. */ + + /* Close the irrelevant side of the pipe and open the relevant side as a + new stream. Mark our side of the pipe to close on exec, so new children + won't see it. */ + if (*mode == 'r') + { + (void) close (pipedes[STDOUT_FILENO]); + (void) fcntl (pipedes[STDIN_FILENO], F_SETFD, FD_CLOEXEC); + stream = fdopen (pipedes[STDIN_FILENO], mode); + } + else + { + (void) close (pipedes[STDIN_FILENO]); + (void) fcntl (pipedes[STDOUT_FILENO], F_SETFD, FD_CLOEXEC); + stream = fdopen (pipedes[STDOUT_FILENO], mode); + } + + if (stream == NULL) + goto error; + + child = (struct child *) malloc (sizeof (struct child)); + if (child == NULL) + goto error; + + { + /* Make sure STREAM has its functions set before + we try to squirrel them away in CHILD. */ + extern void __stdio_check_funcs __P ((FILE *)); + __stdio_check_funcs (stream); + } + + child->pid = pid; + child->cookie = stream->__cookie; + child->funcs = stream->__io_funcs; + stream->__cookie = (PTR) child; + stream->__io_funcs = child_funcs; + stream->__ispipe = 1; + return stream; + + error: + { + /* The stream couldn't be opened or the child structure couldn't be + allocated. Kill the child and close the other side of the pipe. */ + int save = errno; + (void) kill (pid, SIGKILL); + if (stream == NULL) + (void) close (pipedes[*mode == 'r' ? STDOUT_FILENO : STDIN_FILENO]); + else + (void) fclose (stream); +#ifndef NO_WAITPID + (void) waitpid (pid, (int *) NULL, 0); +#else + { + pid_t dead; + do + dead = wait ((int *) NULL); + while (dead > 0 && dead != pid); + } +#endif + errno = save; + return NULL; + } +} + +/* Close a stream opened by popen and return its status. + Returns -1 if the stream was not opened by popen. */ +int +DEFUN(pclose, (stream), register FILE *stream) +{ + struct child *c; + pid_t pid, dead; + int status; + + if (!__validfp(stream) || !stream->__ispipe) + { + errno = EINVAL; + return -1; + } + + c = (struct child *) stream->__cookie; + pid = c->pid; + stream->__cookie = c->cookie; + stream->__io_funcs = c->funcs; + free ((PTR) c); + stream->__ispipe = 0; + if (fclose (stream)) + return -1; + +#ifndef NO_WAITPID + dead = waitpid (pid, &status, 0); +#else + do + dead = wait (&status); + while (dead > 0 && dead != pid); +#endif + if (dead != pid) + status = -1; + + return status; +} |