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 extern char **environ; 51 52 static const char execvPe_err_preamble[] = "execvP: "; 53 static const char execvPe_err_trailer[] = ": path too long\n"; 54 55 int 56 execl(const char *name, const char *arg, ...) 57 { 58 va_list ap; 59 const char **argv; 60 int n; 61 62 va_start(ap, arg); 63 n = 1; 64 while (va_arg(ap, char *) != NULL) 65 n++; 66 va_end(ap); 67 argv = alloca((n + 1) * sizeof(*argv)); 68 if (argv == NULL) { 69 errno = ENOMEM; 70 return (-1); 71 } 72 va_start(ap, arg); 73 n = 1; 74 argv[0] = arg; 75 while ((argv[n] = va_arg(ap, char *)) != NULL) 76 n++; 77 va_end(ap); 78 return (_execve(name, __DECONST(char **, argv), environ)); 79 } 80 81 int 82 execle(const char *name, const char *arg, ...) 83 { 84 va_list ap; 85 const char **argv; 86 char **envp; 87 int n; 88 89 va_start(ap, arg); 90 n = 1; 91 while (va_arg(ap, char *) != NULL) 92 n++; 93 va_end(ap); 94 argv = alloca((n + 1) * sizeof(*argv)); 95 if (argv == NULL) { 96 errno = ENOMEM; 97 return (-1); 98 } 99 va_start(ap, arg); 100 n = 1; 101 argv[0] = arg; 102 while ((argv[n] = va_arg(ap, char *)) != NULL) 103 n++; 104 envp = va_arg(ap, char **); 105 va_end(ap); 106 return (_execve(name, __DECONST(char **, argv), envp)); 107 } 108 109 int 110 execlp(const char *name, const char *arg, ...) 111 { 112 va_list ap; 113 const char **argv; 114 int n; 115 116 va_start(ap, arg); 117 n = 1; 118 while (va_arg(ap, char *) != NULL) 119 n++; 120 va_end(ap); 121 argv = alloca((n + 1) * sizeof(*argv)); 122 if (argv == NULL) { 123 errno = ENOMEM; 124 return (-1); 125 } 126 va_start(ap, arg); 127 n = 1; 128 argv[0] = arg; 129 while ((argv[n] = va_arg(ap, char *)) != NULL) 130 n++; 131 va_end(ap); 132 return (execvp(name, __DECONST(char **, argv))); 133 } 134 135 int 136 execv(const char *name, char * const *argv) 137 { 138 (void)_execve(name, argv, environ); 139 return (-1); 140 } 141 142 int 143 execvp(const char *name, char * const *argv) 144 { 145 return (_execvpe(name, argv, environ)); 146 } 147 148 static int 149 execvPe(const char *name, const char *path, char * const *argv, 150 char * const *envp) 151 { 152 const char **memp; 153 size_t cnt, lp, ln; 154 int eacces, save_errno; 155 char buf[MAXPATHLEN]; 156 const char *bp, *np, *op, *p; 157 struct stat sb; 158 159 eacces = 0; 160 161 /* If it's an absolute or relative path name, it's easy. */ 162 if (strchr(name, '/')) { 163 bp = name; 164 op = NULL; 165 goto retry; 166 } 167 bp = buf; 168 169 /* If it's an empty path name, fail in the usual POSIX way. */ 170 if (*name == '\0') { 171 errno = ENOENT; 172 return (-1); 173 } 174 175 op = path; 176 ln = strlen(name); 177 while (op != NULL) { 178 np = strchrnul(op, ':'); 179 180 /* 181 * It's a SHELL path -- double, leading and trailing colons 182 * mean the current directory. 183 */ 184 if (np == op) { 185 /* Empty component. */ 186 p = "."; 187 lp = 1; 188 } else { 189 /* Non-empty component. */ 190 p = op; 191 lp = np - op; 192 } 193 194 /* Advance to the next component or terminate after this. */ 195 if (*np == '\0') 196 op = NULL; 197 else 198 op = np + 1; 199 200 /* 201 * If the path is too long complain. This is a possible 202 * security issue; given a way to make the path too long 203 * the user may execute the wrong program. 204 */ 205 if (lp + ln + 2 > sizeof(buf)) { 206 (void)_write(STDERR_FILENO, execvPe_err_preamble, 207 sizeof(execvPe_err_preamble) - 1); 208 (void)_write(STDERR_FILENO, p, lp); 209 (void)_write(STDERR_FILENO, execvPe_err_trailer, 210 sizeof(execvPe_err_trailer) - 1); 211 continue; 212 } 213 bcopy(p, buf, lp); 214 buf[lp] = '/'; 215 bcopy(name, buf + lp + 1, ln); 216 buf[lp + ln + 1] = '\0'; 217 218 retry: (void)_execve(bp, argv, envp); 219 switch (errno) { 220 case E2BIG: 221 goto done; 222 case ELOOP: 223 case ENAMETOOLONG: 224 case ENOENT: 225 break; 226 case ENOEXEC: 227 for (cnt = 0; argv[cnt]; ++cnt) 228 ; 229 230 /* 231 * cnt may be 0 above; always allocate at least 232 * 3 entries so that we can at least fit "sh", bp, and 233 * the NULL terminator. We can rely on cnt to take into 234 * account the NULL terminator in all other scenarios, 235 * as we drop argv[0]. 236 */ 237 memp = alloca(MAX(3, cnt + 2) * sizeof(char *)); 238 if (memp == NULL) { 239 /* errno = ENOMEM; XXX override ENOEXEC? */ 240 goto done; 241 } 242 if (cnt > 0) { 243 memp[0] = argv[0]; 244 memp[1] = bp; 245 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 246 } else { 247 memp[0] = "sh"; 248 memp[1] = bp; 249 memp[2] = NULL; 250 } 251 (void)_execve(_PATH_BSHELL, 252 __DECONST(char **, memp), envp); 253 goto done; 254 case ENOMEM: 255 goto done; 256 case ENOTDIR: 257 break; 258 case ETXTBSY: 259 /* 260 * We used to retry here, but sh(1) doesn't. 261 */ 262 goto done; 263 default: 264 /* 265 * EACCES may be for an inaccessible directory or 266 * a non-executable file. Call stat() to decide 267 * which. This also handles ambiguities for EFAULT 268 * and EIO, and undocumented errors like ESTALE. 269 * We hope that the race for a stat() is unimportant. 270 */ 271 save_errno = errno; 272 if (stat(bp, &sb) != 0) 273 break; 274 if (save_errno == EACCES) { 275 eacces = 1; 276 continue; 277 } 278 errno = save_errno; 279 goto done; 280 } 281 } 282 if (eacces) 283 errno = EACCES; 284 else 285 errno = ENOENT; 286 done: 287 return (-1); 288 } 289 290 int 291 execvP(const char *name, const char *path, char * const argv[]) 292 { 293 return execvPe(name, path, argv, environ); 294 } 295 296 int 297 _execvpe(const char *name, char * const argv[], char * const envp[]) 298 { 299 const char *path; 300 301 /* Get the path we're searching. */ 302 if ((path = getenv("PATH")) == NULL) 303 path = _PATH_DEFPATH; 304 305 return (execvPe(name, path, argv, envp)); 306 } 307