lib/sh/oslib.c

   1 /* oslib.c - functions present only in some unix versions. */
   2
   3 /* Copyright (C) 1995,2010 Free Software Foundation, Inc.
   4
   5    This file is part of GNU Bash, the Bourne Again SHell.
   6
   7    Bash is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    Bash is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include <config.h>
  22
  23 #include <bashtypes.h>
  24 #if defined (HAVE_SYS_PARAM_H)
  25 #  include <sys/param.h>
  26 #endif
  27
  28 #if defined (HAVE_UNISTD_H)
  29 #  include <unistd.h>
  30 #endif
  31
  32 #if defined (HAVE_LIMITS_H)
  33 #  include <limits.h>
  34 #endif
  35
  36 #include <posixstat.h>
  37 #include <filecntl.h>
  38 #include <bashansi.h>
  39
  40 #if !defined (HAVE_KILLPG)
  41 #  include <signal.h>
  42 #endif
  43
  44 #include <stdio.h>
  45 #include <errno.h>
  46 #include <chartypes.h>
  47
  48 #include <shell.h>
  49
  50 #if !defined (errno)
  51 extern int errno;
  52 #endif /* !errno */
  53
  54 /* Make the functions strchr and strrchr if they do not exist. */
  55 #if !defined (HAVE_STRCHR)
  56 char *
  57 strchr (string, c)
  58      char *string;
  59      int c;
  60 {
  61   register char *s;
  62
  63   for (s = string; s && *s; s++)
  64     if (*s == c)
  65       return (s);
  66
  67   return ((char *) NULL);
  68 }
  69
  70 char *
  71 strrchr (string, c)
  72      char *string;
  73      int c;
  74 {
  75   register char *s, *t;
  76
  77   for (s = string, t = (char *)NULL; s && *s; s++)
  78     if (*s == c)
  79       t = s;
  80   return (t);
  81 }
  82 #endif /* !HAVE_STRCHR */
  83
  84 #if !defined (HAVE_DUP2) || defined (DUP2_BROKEN)
  85 /* Replacement for dup2 (), for those systems which either don't have it,
  86    or supply one with broken behaviour. */
  87 int
  88 dup2 (fd1, fd2)
  89      int fd1, fd2;
  90 {
  91   int saved_errno, r;
  92
  93   /* If FD1 is not a valid file descriptor, then return immediately with
  94      an error. */
  95   if (fcntl (fd1, F_GETFL, 0) == -1)
  96     return (-1);
  97
  98   if (fd2 < 0 || fd2 >= getdtablesize ())
  99     {
 100       errno = EBADF;
 101       return (-1);
 102     }
 103
 104   if (fd1 == fd2)
 105     return (0);
 106
 107   saved_errno = errno;
 108
 109   (void) close (fd2);
 110   r = fcntl (fd1, F_DUPFD, fd2);
 111
 112   if (r >= 0)
 113     errno = saved_errno;
 114   else
 115     if (errno == EINVAL)
 116       errno = EBADF;
 117
 118   /* Force the new file descriptor to remain open across exec () calls. */
 119   SET_OPEN_ON_EXEC (fd2);
 120   return (r);
 121 }
 122 #endif /* !HAVE_DUP2 */
 123
 124 /*
 125  * Return the total number of available file descriptors.
 126  *
 127  * On some systems, like 4.2BSD and its descendants, there is a system call
 128  * that returns the size of the descriptor table: getdtablesize().  There are
 129  * lots of ways to emulate this on non-BSD systems.
 130  *
 131  * On System V.3, this can be obtained via a call to ulimit:
 132  *      return (ulimit(4, 0L));
 133  *
 134  * On other System V systems, NOFILE is defined in /usr/include/sys/param.h
 135  * (this is what we assume below), so we can simply use it:
 136  *      return (NOFILE);
 137  *
 138  * On POSIX systems, there are specific functions for retrieving various
 139  * configuration parameters:
 140  *      return (sysconf(_SC_OPEN_MAX));
 141  *
 142  */
 143
 144 #if !defined (HAVE_GETDTABLESIZE)
 145 int
 146 getdtablesize ()
 147 {
 148 #  if defined (_POSIX_VERSION) && defined (HAVE_SYSCONF) && defined (_SC_OPEN_MAX)
 149   return (sysconf(_SC_OPEN_MAX));       /* Posix systems use sysconf */
 150 #  else /* ! (_POSIX_VERSION && HAVE_SYSCONF && _SC_OPEN_MAX) */
 151 #    if defined (ULIMIT_MAXFDS)
 152   return (ulimit (4, 0L));      /* System V.3 systems use ulimit(4, 0L) */
 153 #    else /* !ULIMIT_MAXFDS */
 154 #      if defined (NOFILE)      /* Other systems use NOFILE */
 155   return (NOFILE);
 156 #      else /* !NOFILE */
 157   return (20);                  /* XXX - traditional value is 20 */
 158 #      endif /* !NOFILE */
 159 #    endif /* !ULIMIT_MAXFDS */
 160 #  endif /* ! (_POSIX_VERSION && _SC_OPEN_MAX) */
 161 }
 162 #endif /* !HAVE_GETDTABLESIZE */
 163
 164 #if !defined (HAVE_BCOPY)
 165 #  if defined (bcopy)
 166 #    undef bcopy
 167 #  endif
 168 void
 169 bcopy (s,d,n)
 170      char *d, *s;
 171      int n;
 172 {
 173   FASTCOPY (s, d, n);
 174 }
 175 #endif /* !HAVE_BCOPY */
 176
 177 #if !defined (HAVE_BZERO)
 178 #  if defined (bzero)
 179 #    undef bzero
 180 #  endif
 181 void
 182 bzero (s, n)
 183      char *s;
 184      int n;
 185 {
 186   register int i;
 187   register char *r;
 188
 189   for (i = 0, r = s; i < n; i++)
 190     *r++ = '\0';
 191 }
 192 #endif
 193
 194 #if !defined (HAVE_GETHOSTNAME)
 195 #  if defined (HAVE_UNAME)
 196 #    include <sys/utsname.h>
 197 int
 198 gethostname (name, namelen)
 199      char *name;
 200      int namelen;
 201 {
 202   int i;
 203   struct utsname ut;
 204
 205   --namelen;
 206
 207   uname (&ut);
 208   i = strlen (ut.nodename) + 1;
 209   strncpy (name, ut.nodename, i < namelen ? i : namelen);
 210   name[namelen] = '\0';
 211   return (0);
 212 }
 213 #  else /* !HAVE_UNAME */
 214 int
 215 gethostname (name, namelen)
 216      char *name;
 217      int namelen;
 218 {
 219   strncpy (name, "unknown", namelen);
 220   name[namelen] = '\0';
 221   return 0;
 222 }
 223 #  endif /* !HAVE_UNAME */
 224 #endif /* !HAVE_GETHOSTNAME */
 225
 226 #if !defined (HAVE_KILLPG)
 227 int
 228 killpg (pgrp, sig)
 229      pid_t pgrp;
 230      int sig;
 231 {
 232   return (kill (-pgrp, sig));
 233 }
 234 #endif /* !HAVE_KILLPG */
 235
 236 #if !defined (HAVE_MKFIFO) && defined (PROCESS_SUBSTITUTION)
 237 int
 238 mkfifo (path, mode)
 239      char *path;
 240      int mode;
 241 {
 242 #if defined (S_IFIFO)
 243   return (mknod (path, (mode | S_IFIFO), 0));
 244 #else /* !S_IFIFO */
 245   return (-1);
 246 #endif /* !S_IFIFO */
 247 }
 248 #endif /* !HAVE_MKFIFO && PROCESS_SUBSTITUTION */
 249
 250 #define DEFAULT_MAXGROUPS 64
 251
 252 int
 253 getmaxgroups ()
 254 {
 255   static int maxgroups = -1;
 256
 257   if (maxgroups > 0)
 258     return maxgroups;
 259
 260 #if defined (HAVE_SYSCONF) && defined (_SC_NGROUPS_MAX)
 261   maxgroups = sysconf (_SC_NGROUPS_MAX);
 262 #else
 263 #  if defined (NGROUPS_MAX)
 264   maxgroups = NGROUPS_MAX;
 265 #  else /* !NGROUPS_MAX */
 266 #    if defined (NGROUPS)
 267   maxgroups = NGROUPS;
 268 #    else /* !NGROUPS */
 269   maxgroups = DEFAULT_MAXGROUPS;
 270 #    endif /* !NGROUPS */
 271 #  endif /* !NGROUPS_MAX */
 272 #endif /* !HAVE_SYSCONF || !SC_NGROUPS_MAX */
 273
 274   if (maxgroups <= 0)
 275     maxgroups = DEFAULT_MAXGROUPS;
 276
 277   return maxgroups;
 278 }
 279
 280 long
 281 getmaxchild ()
 282 {
 283   static long maxchild = -1L;
 284
 285   if (maxchild > 0)
 286     return maxchild;
 287
 288 #if defined (HAVE_SYSCONF) && defined (_SC_CHILD_MAX)
 289   maxchild = sysconf (_SC_CHILD_MAX);
 290 #else
 291 #  if defined (CHILD_MAX)
 292   maxchild = CHILD_MAX;
 293 #  else
 294 #    if defined (MAXUPRC)
 295   maxchild = MAXUPRC;
 296 #    endif /* MAXUPRC */
 297 #  endif /* CHILD_MAX */
 298 #endif /* !HAVE_SYSCONF || !_SC_CHILD_MAX */
 299
 300   return (maxchild);
 301 }