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. 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  * $FreeBSD: src/lib/libc/gen/exec.c,v 1.15 2000/01/27 23:06:14 jasone Exp $
  34  * $DragonFly: src/lib/libc/gen/exec.c,v 1.7 2005/11/13 00:07:42 swildner Exp $
  35  *
  36  * @(#)exec.c   8.1 (Berkeley) 6/4/93
  37  * $FreeBSD: src/lib/libc/gen/exec.c,v 1.15 2000/01/27 23:06:14 jasone Exp $
  38  */
  39
  40 #include "namespace.h"
  41 #include <sys/param.h>
  42 #include <sys/types.h>
  43 #include <sys/stat.h>
  44 #include <errno.h>
  45 #include <unistd.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <stdio.h>
  49 #include <paths.h>
  50 #include "un-namespace.h"
  51
  52 #include <stdarg.h>
  53
  54 extern char **environ;
  55
  56 int
  57 execl(const char *name, const char *arg, ...)
  58 {
  59         va_list ap;
  60         const char **argv;
  61         int n;
  62
  63         va_start(ap, arg);
  64         n = 1;
  65         while (va_arg(ap, char *) != NULL)
  66                 n++;
  67         va_end(ap);
  68         argv = alloca((n + 1) * sizeof(*argv));
  69         if (argv == NULL) {
  70                 errno = ENOMEM;
  71                 return (-1);
  72         }
  73         va_start(ap, arg);
  74         n = 1;
  75         argv[0] = arg;
  76         while ((argv[n] = va_arg(ap, const char *)) != NULL)
  77                 n++;
  78         va_end(ap);
  79         return (_execve(name, __DECONST(char **, argv),
  80                         __DECONST(char **, environ)));
  81 }
  82
  83 int
  84 execle(const char *name, const char *arg, ...)
  85 {
  86         va_list ap;
  87         const char **argv, **envp;
  88         int n;
  89
  90         va_start(ap, arg);
  91         n = 1;
  92         while (va_arg(ap, char *) != NULL)
  93                 n++;
  94         va_end(ap);
  95         argv = alloca((n + 1) * sizeof(*argv));
  96         if (argv == NULL) {
  97                 errno = ENOMEM;
  98                 return (-1);
  99         }
 100         va_start(ap, arg);
 101         n = 1;
 102         argv[0] = arg;
 103         while ((argv[n] = va_arg(ap, const char *)) != NULL)
 104                 n++;
 105         envp = va_arg(ap, const char **);
 106         va_end(ap);
 107         return (_execve(name, __DECONST(char **, argv),
 108                         __DECONST(char **, envp)));
 109 }
 110
 111 int
 112 execlp(const char *name, const char *arg, ...)
 113 {
 114         va_list ap;
 115         const char **argv;
 116         int n;
 117
 118         va_start(ap, arg);
 119         n = 1;
 120         while (va_arg(ap, char *) != NULL)
 121                 n++;
 122         va_end(ap);
 123         argv = alloca((n + 1) * sizeof(*argv));
 124         if (argv == NULL) {
 125                 errno = ENOMEM;
 126                 return (-1);
 127         }
 128         va_start(ap, arg);
 129         n = 1;
 130         argv[0] = arg;
 131         while ((argv[n] = va_arg(ap, const char *)) != NULL)
 132                 n++;
 133         va_end(ap);
 134         return (execvp(name, __DECONST(char **, argv)));
 135 }
 136
 137 int
 138 execv(const char *name, char * const *argv)
 139 {
 140         _execve(name, argv, environ);
 141         return (-1);
 142 }
 143
 144 int
 145 execvp(const char *name, char * const *argv)
 146 {
 147         const char **memp;
 148         int cnt;
 149         size_t lp, ln;
 150         int eacces, save_errno;
 151         const char *bp, *p, *path;
 152         char *cur, buf[MAXPATHLEN];
 153         struct stat sb;
 154
 155         eacces = 0;
 156
 157         /* If it's an absolute or relative path name, it's easy. */
 158         if (index(name, '/')) {
 159                 bp = name;
 160                 cur = NULL;
 161                 path = 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         /* Get the path we're searching. */
 173         if (!(path = getenv("PATH")))
 174                 path = _PATH_DEFPATH;
 175         cur = alloca(strlen(path) + 1);
 176         if (cur == NULL) {
 177                 errno = ENOMEM;
 178                 return (-1);
 179         }
 180         strcpy(cur, path);
 181         path = cur;
 182         while ( (p = strsep(&cur, ":")) ) {
 183                 /*
 184                  * It's a SHELL path -- double, leading and trailing colons
 185                  * mean the current directory.
 186                  */
 187                 if (!*p) {
 188                         p = ".";
 189                         lp = 1;
 190                 } else
 191                         lp = strlen(p);
 192                 ln = strlen(name);
 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                         _write(STDERR_FILENO, "execvp: ", 8);
 201                         _write(STDERR_FILENO, p, lp);
 202                         _write(STDERR_FILENO, ": path too long\n", 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:          _execve(bp, argv, environ);
 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                         _execve(_PATH_BSHELL, __DECONST(char **, memp), environ);
 230                         goto done;
 231                 case ENOMEM:
 232                         goto done;
 233                 case ENOTDIR:
 234                         break;
 235                 case ETXTBSY:
 236                         /*
 237                          * We used to retry here, but sh(1) doesn't.
 238                          */
 239                         goto done;
 240                 default:
 241                         /*
 242                          * EACCES may be for an inaccessible directory or
 243                          * a non-executable file.  Call stat() to decide
 244                          * which.  This also handles ambiguities for EFAULT
 245                          * and EIO, and undocumented errors like ESTALE.
 246                          * We hope that the race for a stat() is unimportant.
 247                          */
 248                         save_errno = errno;
 249                         if (stat(bp, &sb) != 0)
 250                                 break;
 251                         if (save_errno == EACCES) {
 252                                 eacces = 1;
 253                                 continue;
 254                         }
 255                         errno = save_errno;
 256                         goto done;
 257                 }
 258         }
 259         if (eacces)
 260                 errno = EACCES;
 261         else
 262                 errno = ENOENT;
 263 done:
 264         return (-1);
 265 }