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124 lines
2.8 KiB
124 lines
2.8 KiB
/*
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* llseek.c -- stub calling the llseek system call
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*
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* Copyright (C) 1994 Remy Card. This file may be redistributed
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* under the terms of the GNU Public License.
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*
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* This file is borrowed from the util-linux-2.10q tarball's implementation
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* of fdisk. It allows seeks to 64 bit offsets, if supported.
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* Changed "ext2_" prefix to "llse".
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*/
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#include <sys/types.h>
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#include <errno.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <linux/unistd.h> /* for __NR_llseek */
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#if defined(__GNUC__) || defined(HAS_LONG_LONG)
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typedef long long llse_loff_t;
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#else
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typedef long llse_loff_t;
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#endif
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extern llse_loff_t llse_llseek(unsigned int, llse_loff_t, unsigned int);
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#ifdef __linux__
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#if defined(__alpha__) || defined(__ia64__)
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#ifdef __NR_lseek
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static off_t my_lseek(int fd, off_t off, int whence)
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{
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return syscall(__NR_lseek, fd, off, whence);
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}
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#else /* undefined __NR_lseek */
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static off_t my_lseek(int fd, off_t off, int whence)
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{
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errno = ENOSYS;
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return -1;
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}
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#endif /* __NR_lseek */
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#define my_llseek my_lseek
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#else /* !__alpha__ && !__ia64__ */
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static int _llseek(unsigned int, unsigned long,
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unsigned long, llse_loff_t *, unsigned int);
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#ifndef __NR_llseek
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/* no __NR_llseek on compilation machine - might give it explicitly */
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static int _llseek(unsigned int fd, unsigned long oh,
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unsigned long ol, llse_loff_t * result, unsigned int origin)
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{
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errno = ENOSYS;
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return -1;
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}
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#else
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static int _llseek(unsigned int fd, unsigned long oh,
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unsigned long ol, llse_loff_t * result, unsigned int origin)
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{
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return syscall(__NR_llseek, fd, oh, ol, result, origin);
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}
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#endif
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static llse_loff_t my_llseek(unsigned int fd, llse_loff_t offset,
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unsigned int origin)
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{
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llse_loff_t result;
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int retval;
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retval = _llseek(fd, ((unsigned long long)offset) >> 32,
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((unsigned long long)offset) & 0xffffffff,
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&result, origin);
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return (retval == -1 ? (llse_loff_t) retval : result);
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}
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#endif /* __alpha__ */
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llse_loff_t llse_llseek(unsigned int fd, llse_loff_t offset,
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unsigned int origin)
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{
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llse_loff_t result;
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static int do_compat = 0;
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if (!do_compat) {
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result = my_llseek(fd, offset, origin);
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if (!(result == -1 && errno == ENOSYS))
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return result;
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/*
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* Just in case this code runs on top of an old kernel
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* which does not support the llseek system call
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*/
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do_compat = 1;
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/*
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* Now try ordinary lseek.
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*/
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}
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if ((sizeof(off_t) >= sizeof(llse_loff_t)) ||
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(offset < ((llse_loff_t) 1 << ((sizeof(off_t) * 8) - 1))))
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return lseek(fd, (off_t) offset, origin);
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errno = EINVAL;
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return -1;
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}
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#else /* !linux */
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llse_loff_t llse_llseek(unsigned int fd, llse_loff_t offset,
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unsigned int origin)
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{
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if ((sizeof(off_t) < sizeof(llse_loff_t)) &&
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(offset >= ((llse_loff_t) 1 << ((sizeof(off_t) * 8) - 1)))) {
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errno = EINVAL;
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return -1;
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}
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return lseek(fd, (off_t) offset, origin);
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}
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#endif /* linux */
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