gen/FreeBSD/exec.c

   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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)exec.c      8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/exec.c,v 1.27 2009/12/05 18:55:16 ed Exp $");
  35
  36 #include "namespace.h"
  37 #include <sys/param.h>
  38 #include <sys/types.h>
  39 #include <sys/stat.h>
  40 #include <errno.h>
  41 #include <unistd.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <stdio.h>
  45 #include <paths.h>
  46
  47 #include <stdarg.h>
  48 #include "un-namespace.h"
  49 #include "libc_private.h"
  50
  51 extern char **environ;
  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(name, argv)
 135         const char *name;
 136         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 *cur, buf[MAXPATHLEN];
 156         const char *p, *bp;
 157         struct stat sb;
 158
 159         eacces = 0;
 160
 161         /* If it's an absolute or relative path name, it's easy. */
 162         if (index(name, '/')) {
 163                 bp = name;
 164                 cur = 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         cur = alloca(strlen(path) + 1);
 176         if (cur == NULL) {
 177                 errno = ENOMEM;
 178                 return (-1);
 179         }
 180         strcpy(cur, path);
 181         while ((p = strsep(&cur, ":")) != NULL) {
 182                 /*
 183                  * It's a SHELL path -- double, leading and trailing colons
 184                  * mean the current directory.
 185                  */
 186                 if (*p == '\0') {
 187                         p = ".";
 188                         lp = 1;
 189                 } else
 190                         lp = strlen(p);
 191                 ln = strlen(name);
 192
 193                 /*
 194                  * If the path is too long complain.  This is a possible
 195                  * security issue; given a way to make the path too long
 196                  * the user may execute the wrong program.
 197                  */
 198                 if (lp + ln + 2 > sizeof(buf)) {
 199                         (void)_write(STDERR_FILENO, "execvP: ", 8);
 200                         (void)_write(STDERR_FILENO, p, lp);
 201                         (void)_write(STDERR_FILENO, ": path too long\n",
 202                             16);
 203                         continue;
 204                 }
 205                 bcopy(p, buf, lp);
 206                 buf[lp] = '/';
 207                 bcopy(name, buf + lp + 1, ln);
 208                 buf[lp + ln + 1] = '\0';
 209
 210 retry:          (void)_execve(bp, argv, envp);
 211                 switch (errno) {
 212                 case E2BIG:
 213                         goto done;
 214                 case ELOOP:
 215                 case ENAMETOOLONG:
 216                 case ENOENT:
 217                         break;
 218                 case ENOEXEC:
 219                         for (cnt = 0; argv[cnt]; ++cnt)
 220                                 ;
 221                         memp = alloca((cnt + 2) * sizeof(char *));
 222                         if (memp == NULL) {
 223                                 /* errno = ENOMEM; XXX override ENOEXEC? */
 224                                 goto done;
 225                         }
 226                         memp[0] = "sh";
 227                         memp[1] = bp;
 228                         bcopy(argv + 1, memp + 2, cnt * sizeof(char *));
 229                         (void)_execve(_PATH_BSHELL,
 230                             __DECONST(char **, memp), envp);
 231                         goto done;
 232                 case ENOMEM:
 233                         goto done;
 234                 case ENOTDIR:
 235                         break;
 236                 case ETXTBSY:
 237                         /*
 238                          * We used to retry here, but sh(1) doesn't.
 239                          */
 240                         goto done;
 241                 default:
 242                         /*
 243                          * EACCES may be for an inaccessible directory or
 244                          * a non-executable file.  Call stat() to decide
 245                          * which.  This also handles ambiguities for EFAULT
 246                          * and EIO, and undocumented errors like ESTALE.
 247                          * We hope that the race for a stat() is unimportant.
 248                          */
 249                         save_errno = errno;
 250                         if (stat(bp, &sb) != 0)
 251                                 break;
 252                         if (save_errno == EACCES) {
 253                                 eacces = 1;
 254                                 continue;
 255                         }
 256                         errno = save_errno;
 257                         goto done;
 258                 }
 259         }
 260         if (eacces)
 261                 errno = EACCES;
 262         else
 263                 errno = ENOENT;
 264 done:
 265         return (-1);
 266 }
 267
 268 int
 269 execvP(const char *name, const char *path, char * const argv[])
 270 {
 271         return execvPe(name, path, argv, environ);
 272 }
 273
 274 int
 275 _execvpe(const char *name, char * const argv[], char * const envp[])
 276 {
 277         const char *path;
 278
 279         /* Get the path we're searching. */
 280         if ((path = getenv("PATH")) == NULL)
 281                 path = _PATH_DEFPATH;
 282
 283         return (execvPe(name, path, argv, envp));
 284 }