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/* Copyright (C) 1991, 1992, 1993, 1996, 1997 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., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#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, proto, args) \
static type __CONCAT(child_,name) proto \
{ \
struct child *c = (struct child *) cookie; \
{ \
__ptr_t cookie = c->cookie; \
return (*c->funcs.__CONCAT(__,name)) args; \
} \
}
FUNC (int, read, (void *cookie, char *buf, size_t n), (cookie, buf, n))
FUNC (int, write, (void *cookie, const char *buf, size_t n), (cookie, buf, n))
FUNC (int, seek, (void *cookie, fpos_t *pos, int whence),
(cookie, pos, whence))
FUNC (int, close, (void *cookie), (cookie))
FUNC (int, fileno, (void *cookie), (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 *
popen (command, mode)
const char *command;
const char *mode;
{
pid_t pid;
int pipedes[2];
FILE *stream;
struct child *child;
if (command == NULL || mode == NULL || (*mode != 'r' && *mode != 'w'))
{
__set_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 = (void *) 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
__set_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
pclose (stream)
register FILE *stream;
{
struct child *c;
pid_t pid, dead;
int status;
if (!__validfp (stream) || !stream->__ispipe)
{
__set_errno (EINVAL);
return -1;
}
c = (struct child *) stream->__cookie;
pid = c->pid;
stream->__cookie = c->cookie;
stream->__io_funcs = c->funcs;
free ((void *) 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;
}
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