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popen.c revision 1.4 
      1 /*	$NetBSD: popen.c,v 1.4 1996/06/08 19:48:35 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1980, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #ifndef lint
     37 #if 0
     38 static char sccsid[] = "@(#)popen.c	8.1 (Berkeley) 6/6/93";
     39 #else
     40 static char rcsid[] = "$NetBSD: popen.c,v 1.4 1996/06/08 19:48:35 christos Exp $";
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include "rcv.h"
     45 #include <sys/wait.h>
     46 #include <fcntl.h>
     47 #include "extern.h"
     48 
     49 #define READ 0
     50 #define WRITE 1
     51 
     52 struct fp {
     53 	FILE *fp;
     54 	int pipe;
     55 	int pid;
     56 	struct fp *link;
     57 };
     58 static struct fp *fp_head;
     59 
     60 struct child {
     61 	int pid;
     62 	char done;
     63 	char free;
     64 	union wait status;
     65 	struct child *link;
     66 };
     67 static struct child *child;
     68 static struct child *findchild __P((int));
     69 static void delchild __P((struct child *));
     70 static int file_pid __P((FILE *));
     71 
     72 FILE *
     73 Fopen(file, mode)
     74 	char *file, *mode;
     75 {
     76 	FILE *fp;
     77 
     78 	if ((fp = fopen(file, mode)) != NULL) {
     79 		register_file(fp, 0, 0);
     80 		(void) fcntl(fileno(fp), F_SETFD, 1);
     81 	}
     82 	return fp;
     83 }
     84 
     85 FILE *
     86 Fdopen(fd, mode)
     87 	int fd;
     88 	char *mode;
     89 {
     90 	FILE *fp;
     91 
     92 	if ((fp = fdopen(fd, mode)) != NULL) {
     93 		register_file(fp, 0, 0);
     94 		(void) fcntl(fileno(fp), F_SETFD, 1);
     95 	}
     96 	return fp;
     97 }
     98 
     99 int
    100 Fclose(fp)
    101 	FILE *fp;
    102 {
    103 	unregister_file(fp);
    104 	return fclose(fp);
    105 }
    106 
    107 FILE *
    108 Popen(cmd, mode)
    109 	char *cmd;
    110 	char *mode;
    111 {
    112 	int p[2];
    113 	int myside, hisside, fd0, fd1;
    114 	int pid;
    115 	sigset_t nset;
    116 	FILE *fp;
    117 
    118 	if (pipe(p) < 0)
    119 		return NULL;
    120 	(void) fcntl(p[READ], F_SETFD, 1);
    121 	(void) fcntl(p[WRITE], F_SETFD, 1);
    122 	if (*mode == 'r') {
    123 		myside = p[READ];
    124 		fd0 = -1;
    125 		hisside = fd1 = p[WRITE];
    126 	} else {
    127 		myside = p[WRITE];
    128 		hisside = fd0 = p[READ];
    129 		fd1 = -1;
    130 	}
    131 	sigemptyset(&nset);
    132 	if ((pid = start_command(cmd, &nset, fd0, fd1, NOSTR, NOSTR, NOSTR)) < 0) {
    133 		close(p[READ]);
    134 		close(p[WRITE]);
    135 		return NULL;
    136 	}
    137 	(void) close(hisside);
    138 	if ((fp = fdopen(myside, mode)) != NULL)
    139 		register_file(fp, 1, pid);
    140 	return fp;
    141 }
    142 
    143 int
    144 Pclose(ptr)
    145 	FILE *ptr;
    146 {
    147 	int i;
    148 	sigset_t nset, oset;
    149 
    150 	i = file_pid(ptr);
    151 	unregister_file(ptr);
    152 	(void) fclose(ptr);
    153 	sigemptyset(&nset);
    154 	sigaddset(&nset, SIGINT);
    155 	sigaddset(&nset, SIGHUP);
    156 	sigprocmask(SIG_BLOCK, &nset, &oset);
    157 	i = wait_child(i);
    158 	sigprocmask(SIG_SETMASK, &oset, NULL);
    159 	return i;
    160 }
    161 
    162 void
    163 close_all_files()
    164 {
    165 
    166 	while (fp_head)
    167 		if (fp_head->pipe)
    168 			(void) Pclose(fp_head->fp);
    169 		else
    170 			(void) Fclose(fp_head->fp);
    171 }
    172 
    173 void
    174 register_file(fp, pipe, pid)
    175 	FILE *fp;
    176 	int pipe, pid;
    177 {
    178 	struct fp *fpp;
    179 
    180 	if ((fpp = (struct fp *) malloc(sizeof *fpp)) == NULL)
    181 		panic("Out of memory");
    182 	fpp->fp = fp;
    183 	fpp->pipe = pipe;
    184 	fpp->pid = pid;
    185 	fpp->link = fp_head;
    186 	fp_head = fpp;
    187 }
    188 
    189 void
    190 unregister_file(fp)
    191 	FILE *fp;
    192 {
    193 	struct fp **pp, *p;
    194 
    195 	for (pp = &fp_head; (p = *pp) != NULL; pp = &p->link)
    196 		if (p->fp == fp) {
    197 			*pp = p->link;
    198 			free((char *) p);
    199 			return;
    200 		}
    201 	panic("Invalid file pointer");
    202 }
    203 
    204 static int
    205 file_pid(fp)
    206 	FILE *fp;
    207 {
    208 	struct fp *p;
    209 
    210 	for (p = fp_head; p; p = p->link)
    211 		if (p->fp == fp)
    212 			return (p->pid);
    213 	panic("Invalid file pointer");
    214 	/*NOTREACHED*/
    215 }
    216 
    217 /*
    218  * Run a command without a shell, with optional arguments and splicing
    219  * of stdin and stdout.  The command name can be a sequence of words.
    220  * Signals must be handled by the caller.
    221  * "Mask" contains the signals to ignore in the new process.
    222  * SIGINT is enabled unless it's in the mask.
    223  */
    224 /*VARARGS4*/
    225 int
    226 run_command(cmd, mask, infd, outfd, a0, a1, a2)
    227 	char *cmd;
    228 	sigset_t *mask;
    229 	int infd, outfd;
    230 	char *a0, *a1, *a2;
    231 {
    232 	int pid;
    233 
    234 	if ((pid = start_command(cmd, mask, infd, outfd, a0, a1, a2)) < 0)
    235 		return -1;
    236 	return wait_command(pid);
    237 }
    238 
    239 /*VARARGS4*/
    240 int
    241 start_command(cmd, mask, infd, outfd, a0, a1, a2)
    242 	char *cmd;
    243 	sigset_t *mask;
    244 	int infd, outfd;
    245 	char *a0, *a1, *a2;
    246 {
    247 	int pid;
    248 
    249 	if ((pid = vfork()) < 0) {
    250 		perror("fork");
    251 		return -1;
    252 	}
    253 	if (pid == 0) {
    254 		char *argv[100];
    255 		int i = getrawlist(cmd, argv, sizeof argv / sizeof *argv);
    256 
    257 		if ((argv[i++] = a0) != NOSTR &&
    258 		    (argv[i++] = a1) != NOSTR &&
    259 		    (argv[i++] = a2) != NOSTR)
    260 			argv[i] = NOSTR;
    261 		prepare_child(mask, infd, outfd);
    262 		execvp(argv[0], argv);
    263 		perror(argv[0]);
    264 		_exit(1);
    265 	}
    266 	return pid;
    267 }
    268 
    269 void
    270 prepare_child(nset, infd, outfd)
    271 	sigset_t *nset;
    272 	int infd, outfd;
    273 {
    274 	int i;
    275 	sigset_t fset;
    276 
    277 	/*
    278 	 * All file descriptors other than 0, 1, and 2 are supposed to be
    279 	 * close-on-exec.
    280 	 */
    281 	if (infd >= 0)
    282 		dup2(infd, 0);
    283 	if (outfd >= 0)
    284 		dup2(outfd, 1);
    285 	for (i = 1; i <= NSIG; i++)
    286 		if (sigismember(nset, i))
    287 			(void) signal(i, SIG_IGN);
    288 	if (!sigismember(nset, SIGINT))
    289 		(void) signal(SIGINT, SIG_DFL);
    290 	sigfillset(&fset);
    291 	(void) sigprocmask(SIG_UNBLOCK, &fset, NULL);
    292 }
    293 
    294 int
    295 wait_command(pid)
    296 	int pid;
    297 {
    298 
    299 	if (wait_child(pid) < 0) {
    300 		printf("Fatal error in process.\n");
    301 		return -1;
    302 	}
    303 	return 0;
    304 }
    305 
    306 static struct child *
    307 findchild(pid)
    308 	int pid;
    309 {
    310 	register struct child **cpp;
    311 
    312 	for (cpp = &child; *cpp != NULL && (*cpp)->pid != pid;
    313 	     cpp = &(*cpp)->link)
    314 			;
    315 	if (*cpp == NULL) {
    316 		*cpp = (struct child *) malloc(sizeof (struct child));
    317 		(*cpp)->pid = pid;
    318 		(*cpp)->done = (*cpp)->free = 0;
    319 		(*cpp)->link = NULL;
    320 	}
    321 	return *cpp;
    322 }
    323 
    324 static void
    325 delchild(cp)
    326 	register struct child *cp;
    327 {
    328 	register struct child **cpp;
    329 
    330 	for (cpp = &child; *cpp != cp; cpp = &(*cpp)->link)
    331 		;
    332 	*cpp = cp->link;
    333 	free((char *) cp);
    334 }
    335 
    336 void
    337 sigchild(signo)
    338 	int signo;
    339 {
    340 	int pid;
    341 	union wait status;
    342 	register struct child *cp;
    343 
    344 	while ((pid =
    345 	    wait3((int *)&status, WNOHANG, (struct rusage *)0)) > 0) {
    346 		cp = findchild(pid);
    347 		if (cp->free)
    348 			delchild(cp);
    349 		else {
    350 			cp->done = 1;
    351 			cp->status = status;
    352 		}
    353 	}
    354 }
    355 
    356 union wait wait_status;
    357 
    358 /*
    359  * Wait for a specific child to die.
    360  */
    361 int
    362 wait_child(pid)
    363 	int pid;
    364 {
    365 	sigset_t nset, oset;
    366 	register struct child *cp = findchild(pid);
    367 	sigemptyset(&nset);
    368 	sigaddset(&nset, SIGCHLD);
    369 	sigprocmask(SIG_BLOCK, &nset, &oset);
    370 
    371 	while (!cp->done)
    372 		sigsuspend(&oset);
    373 	wait_status = cp->status;
    374 	delchild(cp);
    375 	sigprocmask(SIG_SETMASK, &oset, NULL);
    376 	return wait_status.w_status ? -1 : 0;
    377 }
    378 
    379 /*
    380  * Mark a child as don't care.
    381  */
    382 void
    383 free_child(pid)
    384 	int pid;
    385 {
    386 	sigset_t nset, oset;
    387 	register struct child *cp = findchild(pid);
    388 	sigemptyset(&nset);
    389 	sigaddset(&nset, SIGCHLD);
    390 	sigprocmask(SIG_BLOCK, &nset, &oset);
    391 
    392 	if (cp->done)
    393 		delchild(cp);
    394 	else
    395 		cp->free = 1;
    396 	sigprocmask(SIG_SETMASK, &oset, NULL);
    397 }
    398