1 /* $OpenBSD: exec.c,v 1.22 2015/09/12 14:56:50 guenther Exp $ */ 2 /*- 3 * Copyright (c) 1991, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/types.h> 32 #include <sys/uio.h> 33 34 #include <errno.h> 35 #include <limits.h> 36 #include <paths.h> 37 #include <stdarg.h> 38 #include <stdio.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 43 extern char **environ; 44 45 int 46 execl(const char *name, const char *arg, ...) 47 { 48 va_list ap; 49 char **argv; 50 int n; 51 52 va_start(ap, arg); 53 n = 1; 54 while (va_arg(ap, char *) != NULL) 55 n++; 56 va_end(ap); 57 argv = alloca((n + 1) * sizeof(*argv)); 58 if (argv == NULL) { 59 errno = ENOMEM; 60 return (-1); 61 } 62 va_start(ap, arg); 63 n = 1; 64 argv[0] = (char *)arg; 65 while ((argv[n] = va_arg(ap, char *)) != NULL) 66 n++; 67 va_end(ap); 68 return (execve(name, argv, environ)); 69 } 70 DEF_WEAK(execl); 71 72 int 73 execle(const char *name, const char *arg, ...) 74 { 75 va_list ap; 76 char **argv, **envp; 77 int n; 78 79 va_start(ap, arg); 80 n = 1; 81 while (va_arg(ap, char *) != NULL) 82 n++; 83 va_end(ap); 84 argv = alloca((n + 1) * sizeof(*argv)); 85 if (argv == NULL) { 86 errno = ENOMEM; 87 return (-1); 88 } 89 va_start(ap, arg); 90 n = 1; 91 argv[0] = (char *)arg; 92 while ((argv[n] = va_arg(ap, char *)) != NULL) 93 n++; 94 envp = va_arg(ap, char **); 95 va_end(ap); 96 return (execve(name, argv, envp)); 97 } 98 99 int 100 execlp(const char *name, const char *arg, ...) 101 { 102 va_list ap; 103 char **argv; 104 int n; 105 106 va_start(ap, arg); 107 n = 1; 108 while (va_arg(ap, char *) != NULL) 109 n++; 110 va_end(ap); 111 argv = alloca((n + 1) * sizeof(*argv)); 112 if (argv == NULL) { 113 errno = ENOMEM; 114 return (-1); 115 } 116 va_start(ap, arg); 117 n = 1; 118 argv[0] = (char *)arg; 119 while ((argv[n] = va_arg(ap, char *)) != NULL) 120 n++; 121 va_end(ap); 122 return (execvp(name, argv)); 123 } 124 125 int 126 execv(const char *name, char *const *argv) 127 { 128 (void)execve(name, argv, environ); 129 return (-1); 130 } 131 132 int 133 execvpe(const char *name, char *const *argv, char *const *envp) 134 { 135 char **memp; 136 int cnt; 137 size_t lp, ln, len; 138 char *p; 139 int eacces = 0; 140 char *bp, *cur, *path, buf[PATH_MAX]; 141 142 /* 143 * Do not allow null name 144 */ 145 if (name == NULL || *name == '\0') { 146 errno = ENOENT; 147 return (-1); 148 } 149 150 /* If it's an absolute or relative path name, it's easy. */ 151 if (strchr(name, '/')) { 152 bp = (char *)name; 153 cur = path = NULL; 154 goto retry; 155 } 156 bp = buf; 157 158 /* Get the path we're searching. */ 159 if (!(path = getenv("PATH"))) 160 path = _PATH_DEFPATH; 161 len = strlen(path) + 1; 162 cur = alloca(len); 163 if (cur == NULL) { 164 errno = ENOMEM; 165 return (-1); 166 } 167 strlcpy(cur, path, len); 168 path = cur; 169 while ((p = strsep(&cur, ":"))) { 170 /* 171 * It's a SHELL path -- double, leading and trailing colons 172 * mean the current directory. 173 */ 174 if (!*p) { 175 p = "."; 176 lp = 1; 177 } else 178 lp = strlen(p); 179 ln = strlen(name); 180 181 /* 182 * If the path is too long complain. This is a possible 183 * security issue; given a way to make the path too long 184 * the user may execute the wrong program. 185 */ 186 if (lp + ln + 2 > sizeof(buf)) { 187 struct iovec iov[3]; 188 189 iov[0].iov_base = "execvp: "; 190 iov[0].iov_len = 8; 191 iov[1].iov_base = p; 192 iov[1].iov_len = lp; 193 iov[2].iov_base = ": path too long\n"; 194 iov[2].iov_len = 16; 195 (void)writev(STDERR_FILENO, iov, 3); 196 continue; 197 } 198 bcopy(p, buf, lp); 199 buf[lp] = '/'; 200 bcopy(name, buf + lp + 1, ln); 201 buf[lp + ln + 1] = '\0'; 202 203 retry: (void)execve(bp, argv, envp); 204 switch(errno) { 205 case E2BIG: 206 goto done; 207 case EISDIR: 208 case ELOOP: 209 case ENAMETOOLONG: 210 case ENOENT: 211 break; 212 case ENOEXEC: 213 for (cnt = 0; argv[cnt]; ++cnt) 214 ; 215 memp = alloca((cnt + 2) * sizeof(char *)); 216 if (memp == NULL) 217 goto done; 218 memp[0] = "sh"; 219 memp[1] = bp; 220 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 221 (void)execve(_PATH_BSHELL, memp, envp); 222 goto done; 223 case ENOMEM: 224 goto done; 225 case ENOTDIR: 226 break; 227 case ETXTBSY: 228 /* 229 * We used to retry here, but sh(1) doesn't. 230 */ 231 goto done; 232 case EACCES: 233 eacces = 1; 234 break; 235 default: 236 goto done; 237 } 238 } 239 if (eacces) 240 errno = EACCES; 241 else if (!errno) 242 errno = ENOENT; 243 done: 244 return (-1); 245 } 246 DEF_WEAK(execvpe); 247 248 int 249 execvp(const char *name, char *const *argv) 250 { 251 return execvpe(name, argv, environ); 252 } 253 DEF_WEAK(execvp); 254 255