diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/openat.c')
| -rw-r--r-- | sysdeps/unix/sysv/linux/openat.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/openat.c b/sysdeps/unix/sysv/linux/openat.c new file mode 100644 index 0000000000..df53b6cf2c --- /dev/null +++ b/sysdeps/unix/sysv/linux/openat.c @@ -0,0 +1,175 @@ +/* Copyright (C) 2005, 2006 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#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 + + INTERNAL_SYSCALL_DECL (err); + 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 + 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); + + /* 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) |