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  * 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  * @(#)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  * $DragonFly: src/lib/libc/gen/exec.c,v 1.7 2005/11/13 00:07:42 swildner Exp $
  32  */
  33
  34 #include "namespace.h"
  35 #include <sys/param.h>
  36 #include <sys/types.h>
  37 #include <sys/stat.h>
  38 #include <errno.h>
  39 #include <unistd.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <stdio.h>
  43 #include <paths.h>
  44
  45 #include <stdarg.h>
  46 #include "un-namespace.h"
  47 #include "libc_private.h"
  48
  49 extern char **environ;
  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, const char *)) != NULL)
  72                 n++;
  73         va_end(ap);
  74         return (_execve(name, __DECONST(char **, argv),
  75                         __DECONST(char **, environ)));
  76 }
  77
  78 int
  79 execle(const char *name, const char *arg, ...)
  80 {
  81         va_list ap;
  82         const char **argv, **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, const char *)) != NULL)
  99                 n++;
 100         envp = va_arg(ap, const char **);
 101         va_end(ap);
 102         return (_execve(name, __DECONST(char **, argv),
 103                         __DECONST(char **, envp)));
 104 }
 105
 106 int
 107 execlp(const char *name, const char *arg, ...)
 108 {
 109         va_list ap;
 110         const char **argv;
 111         int n;
 112
 113         va_start(ap, arg);
 114         n = 1;
 115         while (va_arg(ap, char *) != NULL)
 116                 n++;
 117         va_end(ap);
 118         argv = alloca((n + 1) * sizeof(*argv));
 119         if (argv == NULL) {
 120                 errno = ENOMEM;
 121                 return (-1);
 122         }
 123         va_start(ap, arg);
 124         n = 1;
 125         argv[0] = arg;
 126         while ((argv[n] = va_arg(ap, const char *)) != NULL)
 127                 n++;
 128         va_end(ap);
 129         return (execvp(name, __DECONST(char **, argv)));
 130 }
 131
 132 int
 133 execv(const char *name, char * const *argv)
 134 {
 135         _execve(name, argv, environ);
 136         return (-1);
 137 }
 138
 139 int
 140 execvp(const char *name, char * const *argv)
 141 {
 142         return (_execvpe(name, argv, environ));
 143 }
 144
 145 static int
 146 execvPe(const char *name, const char *path, char * const *argv,
 147         char * const *envp)
 148 {
 149         const char **memp;
 150         int cnt;
 151         size_t lp, ln;
 152         int eacces, save_errno;
 153         const char *bp, *p;
 154         char *cur, buf[MAXPATHLEN];
 155         struct stat sb;
 156
 157         eacces = 0;
 158
 159         /* If it's an absolute or relative path name, it's easy. */
 160         if (index(name, '/')) {
 161                 bp = name;
 162                 cur = NULL;
 163                 goto retry;
 164         }
 165         bp = buf;
 166
 167         /* If it's an empty path name, fail in the usual POSIX way. */
 168         if (*name == '\0') {
 169                 errno = ENOENT;
 170                 return (-1);
 171         }
 172
 173         cur = alloca(strlen(path) + 1);
 174         if (cur == NULL) {
 175                 errno = ENOMEM;
 176                 return (-1);
 177         }
 178         strcpy(cur, path);
 179         while ((p = strsep(&cur, ":")) != NULL) {
 180                 /*
 181                  * It's a SHELL path -- double, leading and trailing colons
 182                  * mean the current directory.
 183                  */
 184                 if (*p == '\0') {
 185                         p = ".";
 186                         lp = 1;
 187                 } else
 188                         lp = strlen(p);
 189                 ln = strlen(name);
 190
 191                 /*
 192                  * If the path is too long complain.  This is a possible
 193                  * security issue; given a way to make the path too long
 194                  * the user may execute the wrong program.
 195                  */
 196                 if (lp + ln + 2 > sizeof(buf)) {
 197                         _write(STDERR_FILENO, "execvP: ", 8);
 198                         _write(STDERR_FILENO, p, lp);
 199                         _write(STDERR_FILENO, ": path too long\n", 16);
 200                         continue;
 201                 }
 202                 bcopy(p, buf, lp);
 203                 buf[lp] = '/';
 204                 bcopy(name, buf + lp + 1, ln);
 205                 buf[lp + ln + 1] = '\0';
 206 retry:
 207                 _execve(bp, argv, environ);
 208                 switch (errno) {
 209                 case E2BIG:
 210                         goto done;
 211                 case ELOOP:
 212                 case ENAMETOOLONG:
 213                 case ENOENT:
 214                         break;
 215                 case ENOEXEC:
 216                         for (cnt = 0; argv[cnt]; ++cnt)
 217                                 ;
 218                         memp = alloca((cnt + 2) * sizeof(char *));
 219                         if (memp == NULL) {
 220                                 /* errno = ENOMEM; XXX override ENOEXEC? */
 221                                 goto done;
 222                         }
 223                         memp[0] = "sh";
 224                         memp[1] = bp;
 225                         bcopy(argv + 1, memp + 2, cnt * sizeof(char *));
 226                         _execve(_PATH_BSHELL, __DECONST(char **, memp), environ);
 227                         goto done;
 228                 case ENOMEM:
 229                         goto done;
 230                 case ENOTDIR:
 231                         break;
 232                 case ETXTBSY:
 233                         /*
 234                          * We used to retry here, but sh(1) doesn't.
 235                          */
 236                         goto done;
 237                 default:
 238                         /*
 239                          * EACCES may be for an inaccessible directory or
 240                          * a non-executable file.  Call stat() to decide
 241                          * which.  This also handles ambiguities for EFAULT
 242                          * and EIO, and undocumented errors like ESTALE.
 243                          * We hope that the race for a stat() is unimportant.
 244                          */
 245                         save_errno = errno;
 246                         if (stat(bp, &sb) != 0)
 247                                 break;
 248                         if (save_errno == EACCES) {
 249                                 eacces = 1;
 250                                 continue;
 251                         }
 252                         errno = save_errno;
 253                         goto done;
 254                 }
 255         }
 256         if (eacces)
 257                 errno = EACCES;
 258         else
 259                 errno = ENOENT;
 260 done:
 261         return (-1);
 262 }
 263
 264 int
 265 execvP(const char *name, const char *path, char * const argv[])
 266 {
 267         return execvPe(name, path, argv, environ);
 268 }
 269
 270 int
 271 _execvpe(const char *name, char * const argv[], char * const envp[])
 272 {
 273         const char *path;
 274
 275         /* Get the path we're searching. */
 276         if ((path = getenv("PATH")) == NULL)
 277                 path = _PATH_DEFPATH;
 278
 279         return (execvPe(name, path, argv, envp));
 280 }