NetBSD/lib/libc/gen/execvp.c

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/* $NetBSD: execvp.c,v 1.10 1998/11/12 16:09:46 christos Exp $ */
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/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
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*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS 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, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93";
#else
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__RCSID("$NetBSD: execvp.c,v 1.10 1998/11/12 16:09:46 christos Exp $");
#endif
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#endif /* LIBC_SCCS and not lint */
#include "namespace.h"
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#include <errno.h>
#include <stdio.h>
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#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
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#include <paths.h>
#include "reentrant.h"
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#ifdef __weak_alias
__weak_alias(execvp,_execvp);
#endif
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extern char **environ;
#ifdef _REENT
extern rwlock_t __environ_lock;
#endif
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int
execvp(name, argv)
const char *name;
char * const *argv;
{
static size_t memsize;
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static const char **memp;
int cnt;
size_t lp, ln;
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char *p;
int eacces = 0;
unsigned int etxtbsy = 0;
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char *cur, *path, buf[PATH_MAX];
const char *bp;
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/* "" is not a valid filename; check this before traversing PATH. */
if (name[0] == '\0') {
errno = ENOENT;
path = NULL;
goto done;
}
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/* If it's an absolute or relative path name, it's easy. */
if (strchr(name, '/')) {
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bp = name;
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cur = path = NULL;
goto retry;
}
bp = buf;
/* Get the path we're searching. */
if (!(path = getenv("PATH")))
path = _PATH_DEFPATH;
cur = path = strdup(path);
while ((p = strsep(&cur, ":")) != NULL) {
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/*
* It's a SHELL path -- double, leading and trailing colons
* mean the current directory.
*/
if (!*p) {
p = ".";
lp = 1;
} else
lp = strlen(p);
ln = strlen(name);
/*
* If the path is too long complain. This is a possible
* security issue; given a way to make the path too long
* the user may execute the wrong program.
*/
if (lp + ln + 2 > sizeof(buf)) {
(void)write(STDERR_FILENO, "execvp: ", 8);
(void)write(STDERR_FILENO, p, lp);
(void)write(STDERR_FILENO, ": path too long\n", 16);
continue;
}
memmove(buf, p, lp);
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buf[lp] = '/';
memmove(buf + lp + 1, name, ln);
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buf[lp + ln + 1] = '\0';
retry: rwlock_rdlock(&__environ_lock);
(void)execve(bp, argv, environ);
rwlock_unlock(&__environ_lock);
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switch(errno) {
case EACCES:
eacces = 1;
break;
case ENOENT:
break;
case ENOEXEC:
for (cnt = 0; argv[cnt]; ++cnt);
if ((cnt + 2) * sizeof(char *) > memsize) {
memsize = (cnt + 2) * sizeof(char *);
if ((memp = realloc(memp, memsize)) == NULL) {
memsize = 0;
goto done;
}
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}
memp[0] = "sh";
memp[1] = bp;
memmove(memp + 2, argv + 1, cnt * sizeof(char *));
rwlock_rdlock(&__environ_lock);
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(void)execve(_PATH_BSHELL, (char * const *)memp, environ);
rwlock_unlock(&__environ_lock);
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goto done;
case ETXTBSY:
if (etxtbsy < 3)
(void)sleep(++etxtbsy);
goto retry;
default:
goto done;
}
}
if (eacces)
errno = EACCES;
else if (!errno)
errno = ENOENT;
done: if (path)
free(path);
return (-1);
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}