kc3-lang/gnulib/lib/ftruncate.c

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• Hash : 7c3f8da8
  Author :
  Date : 2005-09-23T04:15:13
  

  Sync from coreutils.
  
  * .cppi-disable: Add regcomp.c, regex_internal.c, regex_internal.h,
  stat-time.h.
  * argmatch.h: Include verify.h
  (ARGMATCH_VERIFY): Use verify rather than rolling our own.
  (ARGMATCH_ASSERT): Remove; unused.
  * canonicalize.c: Assume STDC_HEADERS.
  * exclude.c: Include "strcase.h".
  * regex_internal.h [!defined _LIBC]: Likewise.
  * getusershell.c: Include stdio--.h rather than stdio.h
  and stdio-safer.h.
  (getusershell): Call fopen, not fopen_safer.
  * save-cwd.c: Include fcntl--.h rather than fcntl.h.
  Do not include unistd-safer.h.
  (save_cwd): Don't call fd_safer; no longer needed
  now that we include fcntl--.h.
  
  * modules/argmatch (Depends-on): Add verify.
  * modules/getloadavg (Depends-on): Depend on fcntl-safer, not
  unistd-safer.
  * modules/save-cwd (Depends-on): Likewise.
  
  * backupfile.m4, calloc.m4, chown.m4, cloexec.m4, dup2.m4:
  * fileblocks.m4, free.m4, ftruncate.m4, getcwd.m4, getpagesize.m4:
  * getugroups.m4, group-member.m4, idcache.m4, link-follow.m4:
  * mkstemp.m4, mktime.m4, mountlist.m4, nanosleep.m4, pathmax.m4:
  * physmem.m4, posixver.m4, putenv.m4, safe-read.m4, same.m4:
  * save-cwd.m4, stdio-safer.m4, unistd-safer.m4, unlinkdir.m4:
  * userspec.m4, xgetcwd.m4, xreadlink.m4:
  Don't bother checking for string.h, stdlib.h, unistd.h.
  * fts.m4 (gl_FUNC_FTS_CORE): Don't require
  AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK; that's now the lstat
  module's job.
  * jm-macros.m4 (gl_MACROS): Likewise.
  * prereq.m4 (gl_PREREQ): Add gl_FUNC_LSTAT.
  
  * backupfile.c: Use ARGMATCH_VERIFY, just in case.
  * posixtm.c (posixtime) [lint]: Initialize *all* of tm0, not just
  the .tm_year member, since otherwise gcc-4.0 would now warn about
  tm_zone, tm_gmtoff, tm_isdst, tm_yday, tm_wday.
  * quotearg.c (quotearg_n_options): Change code to be suboptimal, in
  order to avoid an unsuppressible warning from gcc on 64-bit systems.
  
  * lstat.m4 (gl_FUNC_LSTAT):
  Use AC_LIBSOURCES to require lstat.c and lstat.h.
  Remove obsolete comment.
  * xreadlink.m4: Use AC_LIBSOURCES and AC_LIBOBJ.
  * xstrtod.m4: Likewise.
  

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• lib/ftruncate.c

• /* ftruncate emulations that work on some System V's.
     This file is in the public domain.  */
  
  #ifdef HAVE_CONFIG_H
  # include <config.h>
  #endif
  
  #include <sys/types.h>
  #include <fcntl.h>
  
  #ifdef F_CHSIZE
  
  int
  ftruncate (int fd, off_t length)
  {
    return fcntl (fd, F_CHSIZE, length);
  }
  
  #else /* not F_CHSIZE */
  # ifdef F_FREESP
  
  /* By William Kucharski <kucharsk@netcom.com>.  */
  
  #  include <sys/stat.h>
  #  include <errno.h>
  #  include <unistd.h>
  
  int
  ftruncate (int fd, off_t length)
  {
    struct flock fl;
    struct stat filebuf;
  
    if (fstat (fd, &filebuf) < 0)
      return -1;
  
    if (filebuf.st_size < length)
      {
        /* Extend file length. */
        if (lseek (fd, (length - 1), SEEK_SET) < 0)
  	return -1;
  
        /* Write a "0" byte. */
        if (write (fd, "", 1) != 1)
  	return -1;
      }
    else
      {
  
        /* Truncate length. */
  
        fl.l_whence = 0;
        fl.l_len = 0;
        fl.l_start = length;
        fl.l_type = F_WRLCK;	/* write lock on file space */
  
        /* This relies on the *undocumented* F_FREESP argument to fcntl,
  	 which truncates the file so that it ends at the position
  	 indicated by fl.l_start.  Will minor miracles never cease?  */
  
        if (fcntl (fd, F_FREESP, &fl) < 0)
  	return -1;
      }
  
    return 0;
  }
  
  # else /* not F_CHSIZE nor F_FREESP */
  #  if HAVE_CHSIZE
  
  int
  ftruncate (int fd, off_t length)
  {
    return chsize (fd, length);
  }
  
  #  else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
  
  #   include <errno.h>
  
  int
  ftruncate (int fd, off_t length)
  {
    errno = EIO;
    return -1;
  }
  
  #  endif /* not HAVE_CHSIZE */
  # endif /* not F_FREESP */
  #endif /* not F_CHSIZE */
  

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