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glibc  2.9
Defines | Functions
fxstatat.c File Reference
#include <errno.h>
#include <fcntl.h>
#include <stddef.h>
#include <stdio.h>
#include <sys/stat.h>
#include <kernel_stat.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <bp-checks.h>
#include <kernel-features.h>
#include <xstatconv.h>

Go to the source code of this file.

Defines

#define __fxstatat64   __fxstatat64_disable

Functions

int __fxstatat (int vers, int fd, const char *file, struct stat *st, int flag)

Define Documentation

#define __fxstatat64   __fxstatat64_disable

Definition at line 21 of file fxstatat.c.


Function Documentation

int __fxstatat ( int  vers,
int  fd,
const char *  file,
struct stat st,
int  flag 
)

Definition at line 39 of file fxstatat.c.

{
  int result;
  INTERNAL_SYSCALL_DECL (err);
#ifdef STAT_IS_KERNEL_STAT
# define kst (*st)
#else
  struct kernel_stat kst;
#endif

#ifdef __NR_newfstatat
# ifndef __ASSUME_ATFCTS
  if (__have_atfcts >= 0)
# endif
    {
      result = INTERNAL_SYSCALL (newfstatat, err, 4, fd, file, &kst, flag);
# ifndef __ASSUME_ATFCTS
      if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 1)
         && INTERNAL_SYSCALL_ERRNO (result, err) == ENOSYS)
       __have_atfcts = -1;
      else
# endif
       if (!__builtin_expect (INTERNAL_SYSCALL_ERROR_P (result, err), 1))
         {
#ifdef STAT_IS_KERNEL_STAT
           return 0;
#else
           return __xstat_conv (vers, &kst, st);
#endif
         }
       else
         {
           __set_errno (INTERNAL_SYSCALL_ERRNO (result, err));
           return -1;
         }
    }
#endif

  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 (vers == _STAT_VER_KERNEL)
    {
      if (flag & AT_SYMLINK_NOFOLLOW)
       result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
                               CHECK_1 ((struct kernel_stat *) st));
      else
       result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
                               CHECK_1 ((struct kernel_stat *) st));

      if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
       return result;
    }
#ifdef STAT_IS_KERNEL_STAT
  else
    {
      __set_errno (EINVAL);
      return -1;
    }
#else
  if (flag & AT_SYMLINK_NOFOLLOW)
    result = INTERNAL_SYSCALL (lstat, err, 2, CHECK_STRING (file),
                            __ptrvalue (&kst));
  else
    result = INTERNAL_SYSCALL (stat, err, 2, CHECK_STRING (file),
                            __ptrvalue (&kst));

  if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
    return __xstat_conv (vers, &kst, st);
#endif

  __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);

  return -1;
}

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