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 #include "namespace.h" 35 #include <sys/param.h> 36 #include <sys/stat.h> 37 #include <errno.h> 38 #include <unistd.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <stdio.h> 42 #include <paths.h> 43 44 #include <stdarg.h> 45 #include "un-namespace.h" 46 #include "libc_private.h" 47 48 static const char execvPe_err_preamble[] = "execvP: "; 49 static const char execvPe_err_trailer[] = ": path too long\n"; 50 51 int 52 execl(const char *name, const char *arg, ...) 53 { 54 va_list ap; 55 const char **argv; 56 int n; 57 58 va_start(ap, arg); 59 n = 1; 60 while (va_arg(ap, char *) != NULL) 61 n++; 62 va_end(ap); 63 argv = alloca((n + 1) * sizeof(*argv)); 64 if (argv == NULL) { 65 errno = ENOMEM; 66 return (-1); 67 } 68 va_start(ap, arg); 69 n = 1; 70 argv[0] = arg; 71 while ((argv[n] = va_arg(ap, char *)) != NULL) 72 n++; 73 va_end(ap); 74 return (_execve(name, __DECONST(char **, argv), environ)); 75 } 76 77 int 78 execle(const char *name, const char *arg, ...) 79 { 80 va_list ap; 81 const char **argv; 82 char **envp; 83 int n; 84 85 va_start(ap, arg); 86 n = 1; 87 while (va_arg(ap, char *) != NULL) 88 n++; 89 va_end(ap); 90 argv = alloca((n + 1) * sizeof(*argv)); 91 if (argv == NULL) { 92 errno = ENOMEM; 93 return (-1); 94 } 95 va_start(ap, arg); 96 n = 1; 97 argv[0] = arg; 98 while ((argv[n] = va_arg(ap, char *)) != NULL) 99 n++; 100 envp = va_arg(ap, char **); 101 va_end(ap); 102 return (_execve(name, __DECONST(char **, argv), envp)); 103 } 104 105 int 106 execlp(const char *name, const char *arg, ...) 107 { 108 va_list ap; 109 const char **argv; 110 int n; 111 112 va_start(ap, arg); 113 n = 1; 114 while (va_arg(ap, char *) != NULL) 115 n++; 116 va_end(ap); 117 argv = alloca((n + 1) * sizeof(*argv)); 118 if (argv == NULL) { 119 errno = ENOMEM; 120 return (-1); 121 } 122 va_start(ap, arg); 123 n = 1; 124 argv[0] = arg; 125 while ((argv[n] = va_arg(ap, char *)) != NULL) 126 n++; 127 va_end(ap); 128 return (execvp(name, __DECONST(char **, argv))); 129 } 130 131 int 132 execv(const char *name, char * const *argv) 133 { 134 (void)_execve(name, argv, environ); 135 return (-1); 136 } 137 138 int 139 execvp(const char *name, char * const *argv) 140 { 141 return (_execvpe(name, argv, environ)); 142 } 143 144 static int 145 execvPe(const char *name, const char *path, char * const *argv, 146 char * const *envp) 147 { 148 const char **memp; 149 size_t cnt, lp, ln; 150 int eacces, save_errno; 151 char buf[MAXPATHLEN]; 152 const char *bp, *np, *op, *p; 153 struct stat sb; 154 155 eacces = 0; 156 157 /* If it's an absolute or relative path name, it's easy. */ 158 if (strchr(name, '/')) { 159 bp = name; 160 op = NULL; 161 goto retry; 162 } 163 bp = buf; 164 165 /* If it's an empty path name, fail in the usual POSIX way. */ 166 if (*name == '\0') { 167 errno = ENOENT; 168 return (-1); 169 } 170 171 op = path; 172 ln = strlen(name); 173 while (op != NULL) { 174 np = strchrnul(op, ':'); 175 176 /* 177 * It's a SHELL path -- double, leading and trailing colons 178 * mean the current directory. 179 */ 180 if (np == op) { 181 /* Empty component. */ 182 p = "."; 183 lp = 1; 184 } else { 185 /* Non-empty component. */ 186 p = op; 187 lp = np - op; 188 } 189 190 /* Advance to the next component or terminate after this. */ 191 if (*np == '\0') 192 op = NULL; 193 else 194 op = np + 1; 195 196 /* 197 * If the path is too long complain. This is a possible 198 * security issue; given a way to make the path too long 199 * the user may execute the wrong program. 200 */ 201 if (lp + ln + 2 > sizeof(buf)) { 202 (void)_write(STDERR_FILENO, execvPe_err_preamble, 203 sizeof(execvPe_err_preamble) - 1); 204 (void)_write(STDERR_FILENO, p, lp); 205 (void)_write(STDERR_FILENO, execvPe_err_trailer, 206 sizeof(execvPe_err_trailer) - 1); 207 continue; 208 } 209 bcopy(p, buf, lp); 210 buf[lp] = '/'; 211 bcopy(name, buf + lp + 1, ln); 212 buf[lp + ln + 1] = '\0'; 213 214 retry: (void)_execve(bp, argv, envp); 215 switch (errno) { 216 case E2BIG: 217 goto done; 218 case ELOOP: 219 case ENAMETOOLONG: 220 case ENOENT: 221 break; 222 case ENOEXEC: 223 for (cnt = 0; argv[cnt]; ++cnt) 224 ; 225 226 /* 227 * cnt may be 0 above; always allocate at least 228 * 3 entries so that we can at least fit "sh", bp, and 229 * the NULL terminator. We can rely on cnt to take into 230 * account the NULL terminator in all other scenarios, 231 * as we drop argv[0]. 232 */ 233 memp = alloca(MAX(3, cnt + 2) * sizeof(char *)); 234 if (memp == NULL) { 235 /* errno = ENOMEM; XXX override ENOEXEC? */ 236 goto done; 237 } 238 if (cnt > 0) { 239 memp[0] = argv[0]; 240 memp[1] = bp; 241 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 242 } else { 243 memp[0] = "sh"; 244 memp[1] = bp; 245 memp[2] = NULL; 246 } 247 (void)_execve(_PATH_BSHELL, 248 __DECONST(char **, memp), envp); 249 goto done; 250 case ENOMEM: 251 goto done; 252 case ENOTDIR: 253 break; 254 case ETXTBSY: 255 /* 256 * We used to retry here, but sh(1) doesn't. 257 */ 258 goto done; 259 default: 260 /* 261 * EACCES may be for an inaccessible directory or 262 * a non-executable file. Call stat() to decide 263 * which. This also handles ambiguities for EFAULT 264 * and EIO, and undocumented errors like ESTALE. 265 * We hope that the race for a stat() is unimportant. 266 */ 267 save_errno = errno; 268 if (stat(bp, &sb) != 0) 269 break; 270 if (save_errno == EACCES) { 271 eacces = 1; 272 continue; 273 } 274 errno = save_errno; 275 goto done; 276 } 277 } 278 if (eacces) 279 errno = EACCES; 280 else 281 errno = ENOENT; 282 done: 283 return (-1); 284 } 285 286 int 287 execvP(const char *name, const char *path, char * const argv[]) 288 { 289 return execvPe(name, path, argv, environ); 290 } 291 292 int 293 _execvpe(const char *name, char * const argv[], char * const envp[]) 294 { 295 const char *path; 296 297 /* Get the path we're searching. */ 298 if ((path = getenv("PATH")) == NULL) 299 path = _PATH_DEFPATH; 300 301 return (execvPe(name, path, argv, envp)); 302 } 303