diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/lseek.c')
-rw-r--r-- | sysdeps/unix/sysv/linux/lseek.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/lseek.c b/sysdeps/unix/sysv/linux/lseek.c new file mode 100644 index 0000000000..3b81bffe92 --- /dev/null +++ b/sysdeps/unix/sysv/linux/lseek.c @@ -0,0 +1,57 @@ +/* Linux lseek implementation, 32 bits off_t. + Copyright (C) 2016 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 <unistd.h> +#include <stdint.h> +#include <sys/types.h> +#include <sysdep.h> +#include <errno.h> + +#ifndef __OFF_T_MATCHES_OFF64_T + +/* Test for overflows of structures where we ask the kernel to fill them + in with standard 64-bit syscalls but return them through APIs that + only expose the low 32 bits of some fields. */ + +static inline off_t lseek_overflow (loff_t res) +{ + off_t retval = (off_t) res; + if (retval == res) + return retval; + + __set_errno (EOVERFLOW); + return (off_t) -1; +} + +off_t +__lseek (int fd, off_t offset, int whence) +{ +# ifdef __NR__llseek + loff_t res; + int rc = INLINE_SYSCALL_CALL (_llseek, fd, + (long) (((uint64_t) (offset)) >> 32), + (long) offset, &res, whence); + return rc ?: lseek_overflow (res); +# else + return INLINE_SYSCALL_CALL (lseek, fd, offset, whence); +# endif +} +libc_hidden_def (__lseek) +weak_alias (__lseek, lseek) +strong_alias (__lseek, __libc_lseek) +#endif /* __OFF_T_MATCHES_OFF64_T */ |