111 lines
2.3 KiB
C
111 lines
2.3 KiB
C
/*
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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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#include <sys/types.h>
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#include <errno.h>
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#include <unistd.h>
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extern long long ext2_llseek (unsigned int, long long, unsigned int);
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#ifdef __linux__
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#ifdef HAVE_LLSEEK
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#include <syscall.h>
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#else /* HAVE_LLSEEK */
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#if defined(__alpha__) || defined(__ia64__) || defined(__s390x__)
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#define my_llseek lseek
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#else
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#include <linux/unistd.h> /* for __NR__llseek */
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static int _llseek (unsigned int, unsigned long,
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unsigned long, long long *, unsigned int);
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#ifdef __NR__llseek
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static _syscall5(int,_llseek,unsigned int,fd,unsigned long,offset_high,
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unsigned long, offset_low,long long *,result,
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unsigned int, origin)
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#else
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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, long long *result,
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unsigned int origin) {
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errno = ENOSYS;
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return -1;
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}
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#endif
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static long long my_llseek (unsigned int fd, long long offset,
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unsigned int origin)
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{
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long long 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 ? (long long) retval : result);
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}
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#endif /* __alpha__ */
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#endif /* HAVE_LLSEEK */
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long long ext2_llseek (unsigned int fd, long long offset,
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unsigned int origin)
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{
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long long 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(long long)) ||
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(offset < ((long long) 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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long long ext2_llseek (unsigned int fd, long long offset,
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unsigned int origin)
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{
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if ((sizeof(off_t) < sizeof(long long)) &&
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(offset >= ((long long) 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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