Annotation of prex/usr/lib/libc/gen/execvp.c, Revision 1.1
1.1 ! nbrk 1: /*-
! 2: * Copyright (c) 1991, 1993
! 3: * The Regents of the University of California. All rights reserved.
! 4: *
! 5: * Redistribution and use in source and binary forms, with or without
! 6: * modification, are permitted provided that the following conditions
! 7: * are met:
! 8: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice, this list of conditions and the following disclaimer in the
! 12: * documentation and/or other materials provided with the distribution.
! 13: * 3. Neither the name of the University nor the names of its contributors
! 14: * may be used to endorse or promote products derived from this software
! 15: * without specific prior written permission.
! 16: *
! 17: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 20: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 27: * SUCH DAMAGE.
! 28: */
! 29:
! 30: #include <sys/cdefs.h>
! 31: #include <assert.h>
! 32: #include <errno.h>
! 33: #include <stdio.h>
! 34: #include <stdlib.h>
! 35: #include <string.h>
! 36: #include <limits.h>
! 37: #include <paths.h>
! 38: #include <unistd.h>
! 39:
! 40: extern char **environ;
! 41:
! 42: int
! 43: execvp(const char *name, char * const *argv)
! 44: {
! 45: const char **memp;
! 46: int cnt;
! 47: size_t lp, ln = 0;
! 48: int eacces = 0;
! 49: unsigned int etxtbsy = 0;
! 50: char buf[PATH_MAX];
! 51: const char *bp, *path, *p;
! 52:
! 53: /* "" is not a valid filename; check this before traversing PATH. */
! 54: if (name[0] == '\0') {
! 55: errno = ENOENT;
! 56: goto done;
! 57: }
! 58: /* If it's an absolute or relative path name, it's easy. */
! 59: if (strchr(name, '/')) {
! 60: bp = name;
! 61: path = "";
! 62: goto retry;
! 63: }
! 64: bp = buf;
! 65:
! 66: /* Get the path we're searching. */
! 67: if (!(path = getenv("PATH")))
! 68: path = _PATH_DEFPATH;
! 69:
! 70: ln = strlen(name);
! 71: do {
! 72: /* Find the end of this path element. */
! 73: for (p = path; *path != 0 && *path != ':'; path++)
! 74: continue;
! 75: /*
! 76: * It's a SHELL path -- double, leading and trailing colons
! 77: * mean the current directory.
! 78: */
! 79: if (p == path) {
! 80: p = ".";
! 81: lp = 1;
! 82: } else
! 83: lp = path - p;
! 84:
! 85: /*
! 86: * If the path is too long complain. This is a possible
! 87: * security issue; given a way to make the path too long
! 88: * the user may execute the wrong program.
! 89: */
! 90: if (lp + ln + 2 > sizeof(buf))
! 91: continue;
! 92: memcpy(buf, p, lp);
! 93: buf[lp] = '/';
! 94: memcpy(buf + lp + 1, name, ln);
! 95: buf[lp + ln + 1] = '\0';
! 96:
! 97: retry: (void)execve(bp, argv, environ);
! 98: switch (errno) {
! 99: case EACCES:
! 100: eacces = 1;
! 101: break;
! 102: case ENOTDIR:
! 103: case ENOENT:
! 104: break;
! 105: case ENOEXEC:
! 106: for (cnt = 0; argv[cnt] != NULL; ++cnt)
! 107: continue;
! 108: if ((memp = alloca((cnt + 2) * sizeof(*memp))) == NULL)
! 109: goto done;
! 110: memp[0] = _PATH_BSHELL;
! 111: memp[1] = bp;
! 112: (void)memcpy(&memp[2], &argv[1], cnt * sizeof(*memp));
! 113: (void)execve(_PATH_BSHELL, (char * const *)memp,
! 114: environ);
! 115: goto done;
! 116: case ETXTBSY:
! 117: if (etxtbsy < 3)
! 118: (void)sleep(++etxtbsy);
! 119: goto retry;
! 120: default:
! 121: goto done;
! 122: }
! 123: } while (*path++ == ':'); /* Otherwise, *path was NUL */
! 124: if (eacces)
! 125: errno = EACCES;
! 126: else if (!errno)
! 127: errno = ENOENT;
! 128: done:
! 129: return (-1);
! 130: }
CVSweb