1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __SCCSID("@(#)exec.c 8.1 (Berkeley) 6/4/93"); 34 __FBSDID("$FreeBSD$"); 35 36 #include "namespace.h" 37 #include <sys/param.h> 38 #include <sys/stat.h> 39 #include <errno.h> 40 #include <unistd.h> 41 #include <stdlib.h> 42 #include <string.h> 43 #include <stdio.h> 44 #include <paths.h> 45 46 #include <stdarg.h> 47 #include "un-namespace.h" 48 #include "libc_private.h" 49 50 static const char execvPe_err_preamble[] = "execvP: "; 51 static const char execvPe_err_trailer[] = ": path too long\n"; 52 53 int 54 execl(const char *name, const char *arg, ...) 55 { 56 va_list ap; 57 const char **argv; 58 int n; 59 60 va_start(ap, arg); 61 n = 1; 62 while (va_arg(ap, char *) != NULL) 63 n++; 64 va_end(ap); 65 argv = alloca((n + 1) * sizeof(*argv)); 66 if (argv == NULL) { 67 errno = ENOMEM; 68 return (-1); 69 } 70 va_start(ap, arg); 71 n = 1; 72 argv[0] = arg; 73 while ((argv[n] = va_arg(ap, char *)) != NULL) 74 n++; 75 va_end(ap); 76 return (_execve(name, __DECONST(char **, argv), environ)); 77 } 78 79 int 80 execle(const char *name, const char *arg, ...) 81 { 82 va_list ap; 83 const char **argv; 84 char **envp; 85 int n; 86 87 va_start(ap, arg); 88 n = 1; 89 while (va_arg(ap, char *) != NULL) 90 n++; 91 va_end(ap); 92 argv = alloca((n + 1) * sizeof(*argv)); 93 if (argv == NULL) { 94 errno = ENOMEM; 95 return (-1); 96 } 97 va_start(ap, arg); 98 n = 1; 99 argv[0] = arg; 100 while ((argv[n] = va_arg(ap, char *)) != NULL) 101 n++; 102 envp = va_arg(ap, char **); 103 va_end(ap); 104 return (_execve(name, __DECONST(char **, argv), envp)); 105 } 106 107 int 108 execlp(const char *name, const char *arg, ...) 109 { 110 va_list ap; 111 const char **argv; 112 int n; 113 114 va_start(ap, arg); 115 n = 1; 116 while (va_arg(ap, char *) != NULL) 117 n++; 118 va_end(ap); 119 argv = alloca((n + 1) * sizeof(*argv)); 120 if (argv == NULL) { 121 errno = ENOMEM; 122 return (-1); 123 } 124 va_start(ap, arg); 125 n = 1; 126 argv[0] = arg; 127 while ((argv[n] = va_arg(ap, char *)) != NULL) 128 n++; 129 va_end(ap); 130 return (execvp(name, __DECONST(char **, argv))); 131 } 132 133 int 134 execv(const char *name, char * const *argv) 135 { 136 (void)_execve(name, argv, environ); 137 return (-1); 138 } 139 140 int 141 execvp(const char *name, char * const *argv) 142 { 143 return (_execvpe(name, argv, environ)); 144 } 145 146 static int 147 execvPe(const char *name, const char *path, char * const *argv, 148 char * const *envp) 149 { 150 const char **memp; 151 size_t cnt, lp, ln; 152 int eacces, save_errno; 153 char buf[MAXPATHLEN]; 154 const char *bp, *np, *op, *p; 155 struct stat sb; 156 157 eacces = 0; 158 159 /* If it's an absolute or relative path name, it's easy. */ 160 if (strchr(name, '/')) { 161 bp = name; 162 op = NULL; 163 goto retry; 164 } 165 bp = buf; 166 167 /* If it's an empty path name, fail in the usual POSIX way. */ 168 if (*name == '\0') { 169 errno = ENOENT; 170 return (-1); 171 } 172 173 op = path; 174 ln = strlen(name); 175 while (op != NULL) { 176 np = strchrnul(op, ':'); 177 178 /* 179 * It's a SHELL path -- double, leading and trailing colons 180 * mean the current directory. 181 */ 182 if (np == op) { 183 /* Empty component. */ 184 p = "."; 185 lp = 1; 186 } else { 187 /* Non-empty component. */ 188 p = op; 189 lp = np - op; 190 } 191 192 /* Advance to the next component or terminate after this. */ 193 if (*np == '\0') 194 op = NULL; 195 else 196 op = np + 1; 197 198 /* 199 * If the path is too long complain. This is a possible 200 * security issue; given a way to make the path too long 201 * the user may execute the wrong program. 202 */ 203 if (lp + ln + 2 > sizeof(buf)) { 204 (void)_write(STDERR_FILENO, execvPe_err_preamble, 205 sizeof(execvPe_err_preamble) - 1); 206 (void)_write(STDERR_FILENO, p, lp); 207 (void)_write(STDERR_FILENO, execvPe_err_trailer, 208 sizeof(execvPe_err_trailer) - 1); 209 continue; 210 } 211 bcopy(p, buf, lp); 212 buf[lp] = '/'; 213 bcopy(name, buf + lp + 1, ln); 214 buf[lp + ln + 1] = '\0'; 215 216 retry: (void)_execve(bp, argv, envp); 217 switch (errno) { 218 case E2BIG: 219 goto done; 220 case ELOOP: 221 case ENAMETOOLONG: 222 case ENOENT: 223 break; 224 case ENOEXEC: 225 for (cnt = 0; argv[cnt]; ++cnt) 226 ; 227 228 /* 229 * cnt may be 0 above; always allocate at least 230 * 3 entries so that we can at least fit "sh", bp, and 231 * the NULL terminator. We can rely on cnt to take into 232 * account the NULL terminator in all other scenarios, 233 * as we drop argv[0]. 234 */ 235 memp = alloca(MAX(3, cnt + 2) * sizeof(char *)); 236 if (memp == NULL) { 237 /* errno = ENOMEM; XXX override ENOEXEC? */ 238 goto done; 239 } 240 if (cnt > 0) { 241 memp[0] = argv[0]; 242 memp[1] = bp; 243 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 244 } else { 245 memp[0] = "sh"; 246 memp[1] = bp; 247 memp[2] = NULL; 248 } 249 (void)_execve(_PATH_BSHELL, 250 __DECONST(char **, memp), envp); 251 goto done; 252 case ENOMEM: 253 goto done; 254 case ENOTDIR: 255 break; 256 case ETXTBSY: 257 /* 258 * We used to retry here, but sh(1) doesn't. 259 */ 260 goto done; 261 default: 262 /* 263 * EACCES may be for an inaccessible directory or 264 * a non-executable file. Call stat() to decide 265 * which. This also handles ambiguities for EFAULT 266 * and EIO, and undocumented errors like ESTALE. 267 * We hope that the race for a stat() is unimportant. 268 */ 269 save_errno = errno; 270 if (stat(bp, &sb) != 0) 271 break; 272 if (save_errno == EACCES) { 273 eacces = 1; 274 continue; 275 } 276 errno = save_errno; 277 goto done; 278 } 279 } 280 if (eacces) 281 errno = EACCES; 282 else 283 errno = ENOENT; 284 done: 285 return (-1); 286 } 287 288 int 289 execvP(const char *name, const char *path, char * const argv[]) 290 { 291 return execvPe(name, path, argv, environ); 292 } 293 294 int 295 _execvpe(const char *name, char * const argv[], char * const envp[]) 296 { 297 const char *path; 298 299 /* Get the path we're searching. */ 300 if ((path = getenv("PATH")) == NULL) 301 path = _PATH_DEFPATH; 302 303 return (execvPe(name, path, argv, envp)); 304 } 305