exec.c revision 44984
1/*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34#if defined(LIBC_SCCS) && !defined(lint) 35#if 0 36static char sccsid[] = "@(#)exec.c 8.1 (Berkeley) 6/4/93"; 37#endif 38static const char rcsid[] = 39 "$Id: exec.c,v 1.11 1999/03/23 16:40:34 peter Exp $"; 40#endif /* LIBC_SCCS and not lint */ 41 42#include <sys/param.h> 43#include <sys/types.h> 44#include <sys/stat.h> 45#include <errno.h> 46#include <unistd.h> 47#include <stdlib.h> 48#include <string.h> 49#include <stdio.h> 50#include <paths.h> 51 52#if __STDC__ 53#include <stdarg.h> 54#else 55#include <varargs.h> 56#endif 57 58extern char **environ; 59 60int 61#if __STDC__ 62execl(const char *name, const char *arg, ...) 63#else 64execl(name, arg, va_alist) 65 const char *name; 66 const char *arg; 67 va_dcl 68#endif 69{ 70 va_list ap; 71 char **argv; 72 int n; 73 74#if __STDC__ 75 va_start(ap, arg); 76#else 77 va_start(ap); 78#endif 79 n = 1; 80 while (va_arg(ap, char *) != NULL) 81 n++; 82 va_end(ap); 83 argv = alloca((n + 1) * sizeof(*argv)); 84 if (argv == NULL) { 85 errno = ENOMEM; 86 return (-1); 87 } 88#if __STDC__ 89 va_start(ap, arg); 90#else 91 va_start(ap); 92#endif 93 n = 1; 94 argv[0] = (char *)arg; 95 while ((argv[n] = va_arg(ap, char *)) != NULL) 96 n++; 97 va_end(ap); 98 return (execve(name, argv, environ)); 99} 100 101int 102#if __STDC__ 103execle(const char *name, const char *arg, ...) 104#else 105execle(name, arg, va_alist) 106 const char *name; 107 const char *arg; 108 va_dcl 109#endif 110{ 111 va_list ap; 112 char **argv, **envp; 113 int n; 114 115#if __STDC__ 116 va_start(ap, arg); 117#else 118 va_start(ap); 119#endif 120 n = 1; 121 while (va_arg(ap, char *) != NULL) 122 n++; 123 va_end(ap); 124 argv = alloca((n + 1) * sizeof(*argv)); 125 if (argv == NULL) { 126 errno = ENOMEM; 127 return (-1); 128 } 129#if __STDC__ 130 va_start(ap, arg); 131#else 132 va_start(ap); 133#endif 134 n = 1; 135 argv[0] = (char *)arg; 136 while ((argv[n] = va_arg(ap, char *)) != NULL) 137 n++; 138 envp = va_arg(ap, char **); 139 va_end(ap); 140 return (execve(name, argv, envp)); 141} 142 143int 144#if __STDC__ 145execlp(const char *name, const char *arg, ...) 146#else 147execlp(name, arg, va_alist) 148 const char *name; 149 const char *arg; 150 va_dcl 151#endif 152{ 153 va_list ap; 154 int sverrno; 155 char **argv; 156 int n; 157 158#if __STDC__ 159 va_start(ap, arg); 160#else 161 va_start(ap); 162#endif 163 n = 1; 164 while (va_arg(ap, char *) != NULL) 165 n++; 166 va_end(ap); 167 argv = alloca((n + 1) * sizeof(*argv)); 168 if (argv == NULL) { 169 errno = ENOMEM; 170 return (-1); 171 } 172#if __STDC__ 173 va_start(ap, arg); 174#else 175 va_start(ap); 176#endif 177 n = 1; 178 argv[0] = (char *)arg; 179 while ((argv[n] = va_arg(ap, char *)) != NULL) 180 n++; 181 va_end(ap); 182 return (execvp(name, argv)); 183} 184 185int 186execv(name, argv) 187 const char *name; 188 char * const *argv; 189{ 190 (void)execve(name, argv, environ); 191 return (-1); 192} 193 194int 195execvp(name, argv) 196 const char *name; 197 char * const *argv; 198{ 199 char **memp; 200 register int cnt, lp, ln; 201 register char *p; 202 int eacces, save_errno; 203 char *bp, *cur, *path, buf[MAXPATHLEN]; 204 struct stat sb; 205 206 eacces = 0; 207 208 /* If it's an absolute or relative path name, it's easy. */ 209 if (index(name, '/')) { 210 bp = (char *)name; 211 cur = path = NULL; 212 goto retry; 213 } 214 bp = buf; 215 216 /* If it's an empty path name, fail in the usual POSIX way. */ 217 if (*name == '\0') { 218 errno = ENOENT; 219 return (-1); 220 } 221 222 /* Get the path we're searching. */ 223 if (!(path = getenv("PATH"))) 224 path = _PATH_DEFPATH; 225 cur = alloca(strlen(path) + 1); 226 if (cur == NULL) { 227 errno = ENOMEM; 228 return (-1); 229 } 230 strcpy(cur, path); 231 path = cur; 232 while ( (p = strsep(&cur, ":")) ) { 233 /* 234 * It's a SHELL path -- double, leading and trailing colons 235 * mean the current directory. 236 */ 237 if (!*p) { 238 p = "."; 239 lp = 1; 240 } else 241 lp = strlen(p); 242 ln = strlen(name); 243 244 /* 245 * If the path is too long complain. This is a possible 246 * security issue; given a way to make the path too long 247 * the user may execute the wrong program. 248 */ 249 if (lp + ln + 2 > sizeof(buf)) { 250 (void)write(STDERR_FILENO, "execvp: ", 8); 251 (void)write(STDERR_FILENO, p, lp); 252 (void)write(STDERR_FILENO, ": path too long\n", 16); 253 continue; 254 } 255 bcopy(p, buf, lp); 256 buf[lp] = '/'; 257 bcopy(name, buf + lp + 1, ln); 258 buf[lp + ln + 1] = '\0'; 259 260retry: (void)execve(bp, argv, environ); 261 switch(errno) { 262 case E2BIG: 263 goto done; 264 case ELOOP: 265 case ENAMETOOLONG: 266 case ENOENT: 267 break; 268 case ENOEXEC: 269 for (cnt = 0; argv[cnt]; ++cnt) 270 ; 271 memp = alloca((cnt + 2) * sizeof(char *)); 272 if (memp == NULL) { 273 /* errno = ENOMEM; XXX override ENOEXEC? */ 274 goto done; 275 } 276 memp[0] = "sh"; 277 memp[1] = bp; 278 bcopy(argv + 1, memp + 2, cnt * sizeof(char *)); 279 (void)execve(_PATH_BSHELL, memp, environ); 280 goto done; 281 case ENOMEM: 282 goto done; 283 case ENOTDIR: 284 break; 285 case ETXTBSY: 286 /* 287 * We used to retry here, but sh(1) doesn't. 288 */ 289 goto done; 290 default: 291 /* 292 * EACCES may be for an inaccessible directory or 293 * a non-executable file. Call stat() to decide 294 * which. This also handles ambiguities for EFAULT 295 * and EIO, and undocumented errors like ESTALE. 296 * We hope that the race for a stat() is unimportant. 297 */ 298 save_errno = errno; 299 if (stat(bp, &sb) != 0) 300 break; 301 if (save_errno == EACCES) { 302 eacces = 1; 303 continue; 304 } 305 errno = save_errno; 306 goto done; 307 } 308 } 309 if (eacces) 310 errno = EACCES; 311 else 312 errno = ENOENT; 313done: 314 return (-1); 315} 316