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glibc  2.9
Functions
fchownat.c File Reference
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>
#include <sysdep.h>
#include <stdlib.h>
#include <kernel-features.h>

Go to the source code of this file.

Functions

int fchownat (int fd, const char *file, uid_t owner, gid_t group, int flag)

Function Documentation

int fchownat ( int  fd,
const char *  file,
uid_t  owner,
gid_t  group,
int  flag 
)

Definition at line 38 of file fchownat.c.

{
  int result;

#ifdef __NR_fchownat
# ifndef __ASSUME_ATFCTS
  if (__have_atfcts >= 0)
# endif
    {
      result = INLINE_SYSCALL (fchownat, 5, fd, file, owner, group, flag);
# ifndef __ASSUME_ATFCTS
      if (result == -1 && errno == ENOSYS)
       __have_atfcts = -1;
      else
# endif
       return result;
    }
#endif

#ifndef __ASSUME_ATFCTS
  if (flag & ~AT_SYMLINK_NOFOLLOW)
    {
      __set_errno (EINVAL);
      return -1;
    }

  char *buf = NULL;

  if (fd != AT_FDCWD && file[0] != '/')
    {
      size_t filelen = strlen (file);
      static const char procfd[] = "/proc/self/fd/%d/%s";
      /* Buffer for the path name we are going to use.  It consists of
        - the string /proc/self/fd/
        - the file descriptor number
        - the file name provided.
        The final NUL is included in the sizeof.   A bit of overhead
        due to the format elements compensates for possible negative
        numbers.  */
      size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
      buf = alloca (buflen);

      __snprintf (buf, buflen, procfd, fd, file);
      file = buf;
    }

# if __ASSUME_LCHOWN_SYSCALL
  INTERNAL_SYSCALL_DECL (err);

  if (flag & AT_SYMLINK_NOFOLLOW)
    result = INTERNAL_SYSCALL (lchown, err, 3, file, owner, group);
  else
    result = INTERNAL_SYSCALL (chown, err, 3, file, owner, group);

  if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 0))
    {
      __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
      return -1;
    }
# else
  /* Don't inline the rest to avoid unnecessary code duplication.  */
  if (flag & AT_SYMLINK_NOFOLLOW)
    result = __lchown (file, owner, group);
  else
    result = __chown (file, owner, group);
  if (result < 0)
    __atfct_seterrno (errno, fd, buf);
# endif

  return result;

#endif
}

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