NetBSD/usr.sbin/cron/popen.c

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/* $NetBSD: popen.c,v 1.6 1998/01/31 15:07:14 christos Exp $ */
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/*
* Copyright (c) 1988 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software written by Ken Arnold and
* published in UNIX Review, Vol. 6, No. 8.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley. The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include <sys/cdefs.h>
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#ifndef lint
#if 0
static char rcsid[] = "Id: popen.c,v 1.5 1994/01/15 20:43:43 vixie Exp";
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static char sccsid[] = "@(#)popen.c 5.7 (Berkeley) 2/14/89";
#else
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__RCSID("$NetBSD: popen.c,v 1.6 1998/01/31 15:07:14 christos Exp $");
#endif
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#endif /* not lint */
#include "cron.h"
#include <signal.h>
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/*
* Special version of popen which avoids call to shell. This insures noone
* may create a pipe to a hidden program as a side effect of a list or dir
* command.
*/
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static PID_T *pids;
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static int fds;
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#define MAX_ARGS 1024
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FILE *
cron_popen(program, type)
char *program, *type;
{
char *cp;
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FILE *iop;
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int argc, pdes[2];
PID_T pid;
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char *argv[MAX_ARGS];
#ifdef __GNUC__
(void) &iop; /* Avoid vfork clobbering */
#endif
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if ((*type != 'r' && *type != 'w') || type[1])
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return(NULL);
if (!pids) {
if ((fds = getdtablesize()) <= 0)
return(NULL);
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if (!(pids = (PID_T *)malloc((u_int)(fds * sizeof(PID_T)))))
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return(NULL);
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bzero((char *)pids, fds * sizeof(PID_T));
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}
if (pipe(pdes) < 0)
return(NULL);
/* break up string into pieces */
for (argc = 0, cp = program; argc < MAX_ARGS; cp = NULL)
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if (!(argv[argc++] = strtok(cp, " \t\n")))
break;
iop = NULL;
switch(pid = vfork()) {
case -1: /* error */
(void)close(pdes[0]);
(void)close(pdes[1]);
goto pfree;
/* NOTREACHED */
case 0: /* child */
if (*type == 'r') {
if (pdes[1] != 1) {
dup2(pdes[1], 1);
dup2(pdes[1], 2); /* stderr, too! */
(void)close(pdes[1]);
}
(void)close(pdes[0]);
} else {
if (pdes[0] != 0) {
dup2(pdes[0], 0);
(void)close(pdes[0]);
}
(void)close(pdes[1]);
}
execvp(argv[0], argv);
_exit(1);
}
/* parent; assume fdopen can't fail... */
if (*type == 'r') {
iop = fdopen(pdes[0], type);
(void)close(pdes[1]);
} else {
iop = fdopen(pdes[1], type);
(void)close(pdes[0]);
}
pids[fileno(iop)] = pid;
pfree:
return(iop);
}
int
cron_pclose(iop)
FILE *iop;
{
int fdes;
sigset_t oset, nset;
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WAIT_T stat_loc;
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PID_T pid;
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/*
* pclose returns -1 if stream is not associated with a
* `popened' command, or, if already `pclosed'.
*/
if (pids == 0 || pids[fdes = fileno(iop)] == 0)
return(-1);
(void)fclose(iop);
sigemptyset(&nset);
sigaddset(&nset, SIGINT);
sigaddset(&nset, SIGQUIT);
sigaddset(&nset, SIGHUP);
(void)sigprocmask(SIG_BLOCK, &nset, &oset);
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while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1)
;
(void)sigprocmask(SIG_SETMASK, &oset, NULL);
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pids[fdes] = 0;
return (pid == -1 ? -1 : WEXITSTATUS(stat_loc));
}