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 "namespace.h" 33 #include <sys/param.h> 34 #include <sys/stat.h> 35 #include <errno.h> 36 #include <unistd.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <stdio.h> 40 #include <paths.h> 41 42 #include <stdarg.h> 43 #include "un-namespace.h" 44 #include "libc_private.h" 45 46 static const char execvPe_err_preamble[] = "execvP: "; 47 static const char execvPe_err_trailer[] = ": path too long\n"; 48 49 int 50 execl(const char *name, const char *arg, ...) 51 { 52 va_list ap; 53 const char **argv; 54 int n; 55 56 va_start(ap, arg); 57 n = 1; 58 while (va_arg(ap, char *) != NULL) 59 n++; 60 va_end(ap); 61 argv = alloca((n + 1) * sizeof(*argv)); 62 if (argv == NULL) { 63 errno = ENOMEM; 64 return (-1); 65 } 66 va_start(ap, arg); 67 n = 1; 68 argv[0] = arg; 69 while ((argv[n] = va_arg(ap, char *)) != NULL) 70 n++; 71 va_end(ap); 72 return (_execve(name, __DECONST(char **, argv), environ)); 73 } 74 75 int 76 execle(const char *name, const char *arg, ...) 77 { 78 va_list ap; 79 const char **argv; 80 char **envp; 81 int n; 82 83 va_start(ap, arg); 84 n = 1; 85 while (va_arg(ap, char *) != NULL) 86 n++; 87 va_end(ap); 88 argv = alloca((n + 1) * sizeof(*argv)); 89 if (argv == NULL) { 90 errno = ENOMEM; 91 return (-1); 92 } 93 va_start(ap, arg); 94 n = 1; 95 argv[0] = arg; 96 while ((argv[n] = va_arg(ap, char *)) != NULL) 97 n++; 98 envp = va_arg(ap, char **); 99 va_end(ap); 100 return (_execve(name, __DECONST(char **, argv), envp)); 101 } 102 103 int 104 execlp(const char *name, const char *arg, ...) 105 { 106 va_list ap; 107 const char **argv; 108 int n; 109 110 va_start(ap, arg); 111 n = 1; 112 while (va_arg(ap, char *) != NULL) 113 n++; 114 va_end(ap); 115 argv = alloca((n + 1) * sizeof(*argv)); 116 if (argv == NULL) { 117 errno = ENOMEM; 118 return (-1); 119 } 120 va_start(ap, arg); 121 n = 1; 122 argv[0] = arg; 123 while ((argv[n] = va_arg(ap, char *)) != NULL) 124 n++; 125 va_end(ap); 126 return (execvp(name, __DECONST(char **, argv))); 127 } 128 129 int 130 execv(const char *name, char * const *argv) 131 { 132 (void)_execve(name, argv, environ); 133 return (-1); 134 } 135 136 int 137 execvp(const char *name, char * const *argv) 138 { 139 return (execvpe(name, argv, environ)); 140 } 141 142 static int 143 execvPe(const char *name, const char *path, char * const *argv, 144 char * const *envp) 145 { 146 const char **memp; 147 size_t cnt, lp, ln; 148 int eacces, save_errno; 149 char buf[MAXPATHLEN]; 150 const char *bp, *np, *op, *p; 151 struct stat sb; 152 153 eacces = 0; 154 155 /* If it's an absolute or relative path name, it's easy. */ 156 if (strchr(name, '/')) { 157 bp = name; 158 op = NULL; 159 goto retry; 160 } 161 bp = buf; 162 163 /* If it's an empty path name, fail in the usual POSIX way. */ 164 if (*name == '\0') { 165 errno = ENOENT; 166 return (-1); 167 } 168 169 op = path; 170 ln = strlen(name); 171 while (op != NULL) { 172 np = strchrnul(op, ':'); 173 174 /* 175 * It's a SHELL path -- double, leading and trailing colons 176 * mean the current directory. 177 */ 178 if (np == op) { 179 /* Empty component. */ 180 p = "."; 181 lp = 1; 182 } else { 183 /* Non-empty component. */ 184 p = op; 185 lp = np - op; 186 } 187 188 /* Advance to the next component or terminate after this. */ 189 if (*np == '\0') 190 op = NULL; 191 else 192 op = np + 1; 193 194 /* 195 * If the path is too long complain. This is a possible 196 * security issue; given a way to make the path too long 197 * the user may execute the wrong program. 198 */ 199 if (lp + ln + 2 > sizeof(buf)) { 200 (void)_write(STDERR_FILENO, execvPe_err_preamble, 201 sizeof(execvPe_err_preamble) - 1); 202 (void)_write(STDERR_FILENO, p, lp); 203 (void)_write(STDERR_FILENO, execvPe_err_trailer, 204 sizeof(execvPe_err_trailer) - 1); 205 continue; 206 } 207 bcopy(p, buf, lp); 208 buf[lp] = '/'; 209 bcopy(name, buf + lp + 1, ln); 210 buf[lp + ln + 1] = '\0'; 211 212 retry: (void)_execve(bp, argv, envp); 213 switch (errno) { 214 case E2BIG: 215 goto done; 216 case ELOOP: 217 case ENAMETOOLONG: 218 case ENOENT: 219 break; 220 case ENOEXEC: 221 for (cnt = 0; argv[cnt]; ++cnt) 222 ; 223 224 /* 225 * cnt may be 0 above; always allocate at least 226 * 3 entries so that we can at least fit "sh", bp, and 227 * the NULL terminator. We can rely on cnt to take into 228 * account the NULL terminator in all other scenarios, 229 * as we drop argv[0]. 230 */ 231 memp = alloca(MAX(3, cnt + 2) * sizeof(char *)); 232 if (memp == NULL) { 233 /* errno = ENOMEM; XXX override ENOEXEC? */ 234 goto done; 235 } 236 if (cnt > 0) { 237 memp[0] = argv[0]; 238 memp[1] = bp; 239 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 240 } else { 241 memp[0] = "sh"; 242 memp[1] = bp; 243 memp[2] = NULL; 244 } 245 (void)_execve(_PATH_BSHELL, 246 __DECONST(char **, memp), envp); 247 goto done; 248 case ENOMEM: 249 goto done; 250 case ENOTDIR: 251 break; 252 case ETXTBSY: 253 /* 254 * We used to retry here, but sh(1) doesn't. 255 */ 256 goto done; 257 default: 258 /* 259 * EACCES may be for an inaccessible directory or 260 * a non-executable file. Call stat() to decide 261 * which. This also handles ambiguities for EFAULT 262 * and EIO, and undocumented errors like ESTALE. 263 * We hope that the race for a stat() is unimportant. 264 */ 265 save_errno = errno; 266 if (stat(bp, &sb) != 0) 267 break; 268 if (save_errno == EACCES) { 269 eacces = 1; 270 continue; 271 } 272 errno = save_errno; 273 goto done; 274 } 275 } 276 if (eacces) 277 errno = EACCES; 278 else 279 errno = ENOENT; 280 done: 281 return (-1); 282 } 283 284 int 285 execvP(const char *name, const char *path, char * const argv[]) 286 { 287 return execvPe(name, path, argv, environ); 288 } 289 290 int 291 execvpe(const char *name, char * const argv[], char * const envp[]) 292 { 293 const char *path; 294 295 /* Get the path we're searching. */ 296 if ((path = getenv("PATH")) == NULL) 297 path = _PATH_DEFPATH; 298 299 return (execvPe(name, path, argv, envp)); 300 } 301