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Annotation of prex-old/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: }