lib/libc/gen/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  * 3. 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  * @(#)exec.c   8.1 (Berkeley) 6/4/93
  30  * $FreeBSD: src/lib/libc/gen/exec.c,v 1.25 2008/06/23 05:22:06 ed Exp $
  31  */
  32
  33 #include "namespace.h"
  34 #include <sys/param.h>
  35 #include <sys/types.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 extern char **environ;
  49
  50 int
  51 execl(const char *name, const char *arg, ...)
  52 {
  53         va_list ap;
  54         const char **argv;
  55         int n;
  56
  57         va_start(ap, arg);
  58         n = 1;
  59         while (va_arg(ap, char *) != NULL)
  60                 n++;
  61         va_end(ap);
  62         argv = alloca((n + 1) * sizeof(*argv));
  63         if (argv == NULL) {
  64                 errno = ENOMEM;
  65                 return (-1);
  66         }
  67         va_start(ap, arg);
  68         n = 1;
  69         argv[0] = arg;
  70         while ((argv[n] = va_arg(ap, const char *)) != NULL)
  71                 n++;
  72         va_end(ap);
  73         return (_execve(name, __DECONST(char **, argv),
  74                         __DECONST(char **, environ)));
  75 }
  76
  77 int
  78 execle(const char *name, const char *arg, ...)
  79 {
  80         va_list ap;
  81         const char **argv, **envp;
  82         int n;
  83
  84         va_start(ap, arg);
  85         n = 1;
  86         while (va_arg(ap, char *) != NULL)
  87                 n++;
  88         va_end(ap);
  89         argv = alloca((n + 1) * sizeof(*argv));
  90         if (argv == NULL) {
  91                 errno = ENOMEM;
  92                 return (-1);
  93         }
  94         va_start(ap, arg);
  95         n = 1;
  96         argv[0] = arg;
  97         while ((argv[n] = va_arg(ap, const char *)) != NULL)
  98                 n++;
  99         envp = va_arg(ap, const char **);
 100         va_end(ap);
 101         return (_execve(name, __DECONST(char **, argv),
 102                         __DECONST(char **, 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, const 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         _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         int cnt;
 150         size_t lp, ln;
 151         int eacces, save_errno;
 152         const char *bp, *p;
 153         char *cur, buf[MAXPATHLEN];
 154         struct stat sb;
 155
 156         eacces = 0;
 157
 158         /* If it's an absolute or relative path name, it's easy. */
 159         if (strchr(name, '/')) {
 160                 bp = name;
 161                 cur = NULL;
 162                 goto retry;
 163         }
 164         bp = buf;
 165
 166         /* If it's an empty path name, fail in the usual POSIX way. */
 167         if (*name == '\0') {
 168                 errno = ENOENT;
 169                 return (-1);
 170         }
 171
 172         cur = alloca(strlen(path) + 1);
 173         if (cur == NULL) {
 174                 errno = ENOMEM;
 175                 return (-1);
 176         }
 177         strcpy(cur, path);
 178         while ((p = strsep(&cur, ":")) != NULL) {
 179                 /*
 180                  * It's a SHELL path -- double, leading and trailing colons
 181                  * mean the current directory.
 182                  */
 183                 if (*p == '\0') {
 184                         p = ".";
 185                         lp = 1;
 186                 } else
 187                         lp = strlen(p);
 188                 ln = strlen(name);
 189
 190                 /*
 191                  * If the path is too long complain.  This is a possible
 192                  * security issue; given a way to make the path too long
 193                  * the user may execute the wrong program.
 194                  */
 195                 if (lp + ln + 2 > sizeof(buf)) {
 196                         _write(STDERR_FILENO, "execvP: ", 8);
 197                         _write(STDERR_FILENO, p, lp);
 198                         _write(STDERR_FILENO, ": path too long\n", 16);
 199                         continue;
 200                 }
 201                 bcopy(p, buf, lp);
 202                 buf[lp] = '/';
 203                 bcopy(name, buf + lp + 1, ln);
 204                 buf[lp + ln + 1] = '\0';
 205 retry:
 206                 _execve(bp, argv, envp);
 207                 switch (errno) {
 208                 case E2BIG:
 209                         goto done;
 210                 case ELOOP:
 211                 case ENAMETOOLONG:
 212                 case ENOENT:
 213                         break;
 214                 case ENOEXEC:
 215                         for (cnt = 0; argv[cnt]; ++cnt)
 216                                 ;
 217                         memp = alloca((cnt + 2) * sizeof(char *));
 218                         if (memp == NULL) {
 219                                 /* errno = ENOMEM; XXX override ENOEXEC? */
 220                                 goto done;
 221                         }
 222                         memp[0] = "sh";
 223                         memp[1] = bp;
 224                         bcopy(argv + 1, memp + 2, cnt * sizeof(char *));
 225                         _execve(_PATH_BSHELL, __DECONST(char **, memp), envp);
 226                         goto done;
 227                 case ENOMEM:
 228                         goto done;
 229                 case ENOTDIR:
 230                         break;
 231                 case ETXTBSY:
 232                         /*
 233                          * We used to retry here, but sh(1) doesn't.
 234                          */
 235                         goto done;
 236                 default:
 237                         /*
 238                          * EACCES may be for an inaccessible directory or
 239                          * a non-executable file.  Call stat() to decide
 240                          * which.  This also handles ambiguities for EFAULT
 241                          * and EIO, and undocumented errors like ESTALE.
 242                          * We hope that the race for a stat() is unimportant.
 243                          */
 244                         save_errno = errno;
 245                         if (stat(bp, &sb) != 0)
 246                                 break;
 247                         if (save_errno == EACCES) {
 248                                 eacces = 1;
 249                                 continue;
 250                         }
 251                         errno = save_errno;
 252                         goto done;
 253                 }
 254         }
 255         if (eacces)
 256                 errno = EACCES;
 257         else
 258                 errno = ENOENT;
 259 done:
 260         return (-1);
 261 }
 262
 263 int
 264 execvP(const char *name, const char *path, char * const argv[])
 265 {
 266         return execvPe(name, path, argv, environ);
 267 }
 268
 269 int
 270 _execvpe(const char *name, char * const argv[], char * const envp[])
 271 {
 272         const char *path;
 273
 274         /* Get the path we're searching. */
 275         if ((path = getenv("PATH")) == NULL)
 276                 path = _PATH_DEFPATH;
 277
 278         return (execvPe(name, path, argv, envp));
 279 }