root / prex-0.9.0 / usr / lib / libc / gen / execvp.c @ 03e9c04a
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/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h> |
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#include <assert.h> |
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#include <errno.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <string.h> |
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#include <limits.h> |
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#include <paths.h> |
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#include <unistd.h> |
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extern char **environ; |
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int
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execvp(const char *name, char * const *argv) |
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{ |
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const char **memp; |
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int cnt;
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size_t lp, ln = 0;
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int eacces = 0; |
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unsigned int etxtbsy = 0; |
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char buf[PATH_MAX];
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const char *bp, *path, *p; |
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/* "" is not a valid filename; check this before traversing PATH. */
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if (name[0] == '\0') { |
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errno = ENOENT; |
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goto done;
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} |
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/* If it's an absolute or relative path name, it's easy. */
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if (strchr(name, '/')) { |
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bp = name; |
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path = "";
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goto retry;
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} |
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bp = buf; |
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/* Get the path we're searching. */
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if (!(path = getenv("PATH"))) |
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path = _PATH_DEFPATH; |
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ln = strlen(name); |
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do {
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/* Find the end of this path element. */
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for (p = path; *path != 0 && *path != ':'; path++) |
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continue;
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/*
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* It's a SHELL path -- double, leading and trailing colons
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* mean the current directory.
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*/
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if (p == path) {
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p = ".";
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lp = 1;
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} else
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lp = path - p; |
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/*
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* If the path is too long complain. This is a possible
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* security issue; given a way to make the path too long
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* the user may execute the wrong program.
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*/
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if (lp + ln + 2 > sizeof(buf)) |
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continue;
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memcpy(buf, p, lp); |
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buf[lp] = '/';
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memcpy(buf + lp + 1, name, ln);
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buf[lp + ln + 1] = '\0'; |
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retry: (void)execve(bp, argv, environ); |
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switch (errno) {
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case EACCES:
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eacces = 1;
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break;
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case ENOTDIR:
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case ENOENT:
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break;
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case ENOEXEC:
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for (cnt = 0; argv[cnt] != NULL; ++cnt) |
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continue;
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if ((memp = (const char **)(alloca((cnt + 2) * sizeof(*memp)))) == NULL) |
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goto done;
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memp[0] = _PATH_BSHELL;
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memp[1] = bp;
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(void)memcpy(&memp[2], &argv[1], cnt * sizeof(*memp)); |
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(void)execve(_PATH_BSHELL, (char * const *)memp, |
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environ); |
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goto done;
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case ETXTBSY:
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if (etxtbsy < 3) |
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(void)sleep(++etxtbsy);
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goto retry;
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default:
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goto done;
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} |
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} while (*path++ == ':'); /* Otherwise, *path was NUL */ |
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if (eacces)
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errno = EACCES; |
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else if (!errno) |
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errno = ENOENT; |
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done:
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return (-1); |
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} |