[thirdparty/e2fsprogs.git] / lib / fpopen.c

/*
 * fpopen.c --- unlike the libc popen, it directly executes the
 * command instead of call out to the shell.
 *
 * Copyright Theodore Ts'o, 1996-1999.
 *
 * Permission to use this file is granted for any purposes, as long as
 * this copyright statement is kept intact and the author is not held
 * liable for any damages resulting from the use of this program.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
 * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
 * USE OF THIS SOFTWARE.
 */

#include "config.h"
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>

#define MAX_ARGV 256

extern FILE *fpopen(const char *cmd, const char *mode);

FILE *fpopen(const char *cmd, const char *mode)
{
	char	*argv[MAX_ARGV];
	int	i = 0;
	char	*buf, *prog = 0;
	char	*p;
	int	do_stdin, do_stderr = 0;
	int	fds[2];
	pid_t	pid;

	if (!mode) {
		errno = EFAULT;
		return NULL;
	}

	switch (*mode) {
	case 'r':
		do_stdin = 0;
		break;
	case 'w':
		do_stdin = 1;
		break;
	default:
		errno = EINVAL;
		return NULL;
	}
	switch (*(mode+1)) {
	case '&':
		do_stderr = 1;
	}

	/*
	 * Create the argv vector....
	 */
	buf = malloc(strlen(cmd)+1);
	if (!buf)
		return NULL;
	strcpy(buf, cmd);
	p = buf;
	while (p && *p) {
		if (isspace(*p)) {
			p++;
			continue;
		}
		if (i == 0)
			prog = p;
		argv[i++] = p;
		p = strchr(p, ' ');
		if (p)
			*p++ = 0;
	}

	argv[i] = 0;

	/*
	 * Get the pipe
	 */
	if (pipe(fds) < 0)
		return NULL;

	/* Fork and execute the correct program. */
	if ((pid = fork()) < 0) {
		perror("fork");
		return NULL;
	} else if (pid == 0) {
		if (do_stdin) {
			close(fds[1]);
			dup2(fds[0], 0);
		} else {
			close(fds[0]);
			dup2(fds[1], 1);
			if (do_stderr)
				dup2(fds[1], 2);
		}
		(void) execvp(prog, argv);
		perror(prog);
		exit(1);
	}
	return fdopen(do_stdin ? fds[1] : fds[0], mode);
}
Commit	Line	Data
f3db3566 TT	1	/*
	2	* fpopen.c --- unlike the libc popen, it directly executes the
	3	* command instead of call out to the shell.
e2e69ba4 TT	4	*
	5	* Copyright Theodore Ts'o, 1996-1999.
	6	*
	7	* Permission to use this file is granted for any purposes, as long as
	8	* this copyright statement is kept intact and the author is not held
	9	* liable for any damages resulting from the use of this program.
	10	*
	11	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
	12	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	13	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
	14	* WHICH ARE HEREBY DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
	15	* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	16	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
	17	* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	18	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
	19	* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	20	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
	21	* USE OF THIS SOFTWARE.
f3db3566 TT	22	*/
f3db3566 TT	23
d1154eb4	24	#include "config.h"
f3db3566 TT	25	#include <unistd.h>
	26	#include <stdlib.h>
	27	#include <stdio.h>
	28	#include <errno.h>
	29	#include <string.h>
	30	#include <ctype.h>
	31
	32	#define MAX_ARGV 256
	33
	34	extern FILE fpopen(const char cmd, const char *mode);
	35
	36	FILE fpopen(const char cmd, const char *mode)
	37	{
	38	char *argv[MAX_ARGV];
	39	int i = 0;
	40	char buf, prog = 0;
	41	char *p;
e2e69ba4	42	int do_stdin, do_stderr = 0;
f3db3566 TT	43	int fds[2];
	44	pid_t pid;
	45
	46	if (!mode) {
	47	errno = EFAULT;
	48	return NULL;
	49	}
efc6f628	50
f3db3566 TT	51	switch (*mode) {
	52	case 'r':
	53	do_stdin = 0;
	54	break;
	55	case 'w':
	56	do_stdin = 1;
	57	break;
	58	default:
	59	errno = EINVAL;
	60	return NULL;
	61	}
e2e69ba4 TT	62	switch (*(mode+1)) {
	63	case '&':
	64	do_stderr = 1;
	65	}
f3db3566 TT	66
	67	/*
	68	* Create the argv vector....
	69	*/
	70	buf = malloc(strlen(cmd)+1);
	71	if (!buf)
	72	return NULL;
	73	strcpy(buf, cmd);
	74	p = buf;
	75	while (p && *p) {
	76	if (isspace(*p)) {
	77	p++;
	78	continue;
	79	}
	80	if (i == 0)
	81	prog = p;
	82	argv[i++] = p;
	83	p = strchr(p, ' ');
	84	if (p)
	85	*p++ = 0;
	86	}
	87
	88	argv[i] = 0;
	89
	90	/*
	91	* Get the pipe
	92	*/
	93	if (pipe(fds) < 0)
	94	return NULL;
efc6f628	95
f3db3566 TT	96	/* Fork and execute the correct program. */
	97	if ((pid = fork()) < 0) {
	98	perror("fork");
	99	return NULL;
	100	} else if (pid == 0) {
	101	if (do_stdin) {
	102	close(fds[1]);
	103	dup2(fds[0], 0);
	104	} else {
	105	close(fds[0]);
	106	dup2(fds[1], 1);
e2e69ba4 TT	107	if (do_stderr)
e2e69ba4 TT	108	dup2(fds[1], 2);
f3db3566 TT	109	}
	110	(void) execvp(prog, argv);
	111	perror(prog);
	112	exit(1);
	113	}
	114	return fdopen(do_stdin ? fds[1] : fds[0], mode);
	115	}
	116