sysdeps/unix/sysv/linux/unlinkat.c

   1 /* Copyright (C) 2005 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25
  26
  27 /* Remove the link named NAME.  */
  28 int
  29 unlinkat (fd, file, flag)
  30      int fd;
  31      const char *file;
  32      int flag;
  33 {
  34   if (flag & ~AT_REMOVEDIR)
  35     {
  36       __set_errno (EINVAL);
  37       return -1;
  38     }
  39
  40   char *buf = NULL;
  41
  42   if (fd != AT_FDCWD && file[0] != '/')
  43     {
  44       size_t filelen = strlen (file);
  45       static const char procfd[] = "/proc/self/fd/%d/%s";
  46       /* Buffer for the path name we are going to use.  It consists of
  47          - the string /proc/self/fd/
  48          - the file descriptor number
  49          - the file name provided.
  50          The final NUL is included in the sizeof.   A bit of overhead
  51          due to the format elements compensates for possible negative
  52          numbers.  */
  53       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  54       buf = alloca (buflen);
  55
  56       __snprintf (buf, buflen, procfd, fd, file);
  57       file = buf;
  58     }
  59
  60   int result;
  61   INTERNAL_SYSCALL_DECL (err);
  62
  63   if (flag & AT_REMOVEDIR)
  64     result = INTERNAL_SYSCALL (rmdir, err, 1, file);
  65   else
  66     result = INTERNAL_SYSCALL (unlink, err, 1, file);
  67
  68   if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 0))
  69     {
  70       __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
  71       result = -1;
  72     }
  73
  74   return result;
  75 }