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69 lines
2.3 KiB
C
69 lines
2.3 KiB
C
/* mmap - map files or devices into memory. Linux version.
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Copyright (C) 1999-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sysdep.h>
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#include <mmap_internal.h>
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#ifdef __NR_mmap2
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/* To avoid silent truncation of offset when using mmap2, do not accept
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offset larger than 1 << (page_shift + off_t bits). For archictures with
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32 bits off_t and page size of 4096 it would be 1^44. */
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# define MMAP_OFF_HIGH_MASK \
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((-(MMAP2_PAGE_UNIT << 1) << (8 * sizeof (off_t) - 1)))
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#else
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/* Some ABIs might use __NR_mmap while having sizeof (off_t) smaller than
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sizeof (off64_t) (currently only MIPS64n32). For this case just set
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zero the higher bits so mmap with large offset does not fail. */
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# define MMAP_OFF_HIGH_MASK 0x0
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#endif
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#define MMAP_OFF_MASK (MMAP_OFF_HIGH_MASK | MMAP_OFF_LOW_MASK)
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/* An architecture may override this. */
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#ifndef MMAP_PREPARE
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# define MMAP_PREPARE(addr, len, prot, flags, fd, offset)
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#endif
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void *
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__mmap64 (void *addr, size_t len, int prot, int flags, int fd, off64_t offset)
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{
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MMAP_CHECK_PAGE_UNIT ();
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if (offset & MMAP_OFF_MASK)
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return (void *) INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
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MMAP_PREPARE (addr, len, prot, flags, fd, offset);
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#ifdef __NR_mmap2
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return (void *) MMAP_CALL (mmap2, addr, len, prot, flags, fd,
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(off_t) (offset / MMAP2_PAGE_UNIT));
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#else
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return (void *) MMAP_CALL (mmap, addr, len, prot, flags, fd, offset);
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#endif
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}
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weak_alias (__mmap64, mmap64)
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libc_hidden_def (__mmap64)
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#ifdef __OFF_T_MATCHES_OFF64_T
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weak_alias (__mmap64, mmap)
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weak_alias (__mmap64, __mmap)
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libc_hidden_def (__mmap)
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#endif
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