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glibc/sysdeps/unix/sysv/linux/openat.c
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/* Copyright (C) 2005-2013 Free Software Foundation, Inc. | |
This file is part of the GNU C Library. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Lesser General Public | |
License as published by the Free Software Foundation; either | |
version 2.1 of the License, or (at your option) any later version. | |
The GNU C Library is distributed in the hope that it will be useful, | |
but WITHOUT ANY WARRANTY; without even the implied warranty of | |
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
Lesser General Public License for more details. | |
You should have received a copy of the GNU Lesser General Public | |
License along with the GNU C Library; if not, see | |
<http://www.gnu.org/licenses/>. */ | |
#include <errno.h> | |
#include <fcntl.h> | |
#include <stdarg.h> | |
#include <stddef.h> | |
#include <stdio.h> | |
#include <string.h> | |
#include <sys/stat.h> | |
#include <kernel-features.h> | |
#include <sysdep-cancel.h> | |
#include <not-cancel.h> | |
#ifndef OPENAT | |
# define OPENAT openat | |
# ifndef __ASSUME_ATFCTS | |
/* Set errno after a failed call. If BUF is not null, | |
it is a /proc/self/fd/ path name we just tried to use. */ | |
void | |
attribute_hidden | |
__atfct_seterrno (int errval, int fd, const char *buf) | |
{ | |
if (buf != NULL) | |
{ | |
struct stat64 st; | |
if (errval == ENOTDIR || errval == ENOENT) | |
{ | |
/* This can mean either the file descriptor is invalid or | |
/proc is not mounted. */ | |
if (__fxstat64 (_STAT_VER, fd, &st) != 0) | |
/* errno is already set correctly. */ | |
return; | |
/* If /proc is not mounted there is nothing we can do. */ | |
if ((errval != ENOTDIR || S_ISDIR (st.st_mode)) | |
&& (__xstat64 (_STAT_VER, "/proc/self/fd", &st) != 0 | |
|| !S_ISDIR (st.st_mode))) | |
errval = ENOSYS; | |
} | |
} | |
__set_errno (errval); | |
} | |
int __have_atfcts; | |
# endif | |
#endif | |
#define OPENAT_NOT_CANCEL CONCAT (OPENAT) | |
#define CONCAT(name) CONCAT2 (name) | |
#define CONCAT2(name) __##name##_nocancel | |
int | |
OPENAT_NOT_CANCEL (fd, file, oflag, mode) | |
int fd; | |
const char *file; | |
int oflag; | |
mode_t mode; | |
{ | |
/* We have to add the O_LARGEFILE flag for openat64. */ | |
#ifdef MORE_OFLAGS | |
oflag |= MORE_OFLAGS; | |
#endif | |
int res; | |
#ifdef __NR_openat | |
# ifndef __ASSUME_ATFCTS | |
if (__have_atfcts >= 0) | |
# endif | |
{ | |
res = INLINE_SYSCALL (openat, 4, fd, file, oflag, mode); | |
# ifndef __ASSUME_ATFCTS | |
if (res == -1 && errno == ENOSYS) | |
__have_atfcts = -1; | |
else | |
# endif | |
return res; | |
} | |
#endif | |
#ifndef __ASSUME_ATFCTS | |
INTERNAL_SYSCALL_DECL (err); | |
char *buf = NULL; | |
if (fd != AT_FDCWD && file[0] != '/') | |
{ | |
size_t filelen = strlen (file); | |
if (__builtin_expect (filelen == 0, 0)) | |
{ | |
__set_errno (ENOENT); | |
return -1; | |
} | |
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); | |
/* Note: snprintf cannot be canceled. */ | |
__snprintf (buf, buflen, procfd, fd, file); | |
file = buf; | |
} | |
res = INTERNAL_SYSCALL (open, err, 3, file, oflag, mode); | |
if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (res, err), 0)) | |
{ | |
__atfct_seterrno (INTERNAL_SYSCALL_ERRNO (res, err), fd, buf); | |
res = -1; | |
} | |
return res; | |
#endif | |
} | |
#define UNDERIZE(name) UNDERIZE_1 (name) | |
#define UNDERIZE_1(name) __##name | |
#define __OPENAT UNDERIZE (OPENAT) | |
/* Open FILE with access OFLAG. Interpret relative paths relative to | |
the directory associated with FD. If OFLAG includes O_CREAT, a | |
third argument is the file protection. */ | |
int | |
__OPENAT (fd, file, oflag) | |
int fd; | |
const char *file; | |
int oflag; | |
{ | |
mode_t mode = 0; | |
if (oflag & O_CREAT) | |
{ | |
va_list arg; | |
va_start (arg, oflag); | |
mode = va_arg (arg, mode_t); | |
va_end (arg); | |
} | |
if (SINGLE_THREAD_P) | |
return OPENAT_NOT_CANCEL (fd, file, oflag, mode); | |
int oldtype = LIBC_CANCEL_ASYNC (); | |
int res = OPENAT_NOT_CANCEL (fd, file, oflag, mode); | |
LIBC_CANCEL_RESET (oldtype); | |
return res; | |
} | |
libc_hidden_def (__OPENAT) | |
weak_alias (__OPENAT, OPENAT) |