| 1 | /* mmap - map files or devices into memory. Linux version. |
|---|
| 2 | Copyright (C) 1999-2022 Free Software Foundation, Inc. |
|---|
| 3 | This file is part of the GNU C Library. |
|---|
| 4 | |
|---|
| 5 | The GNU C Library is free software; you can redistribute it and/or |
|---|
| 6 | modify it under the terms of the GNU Lesser General Public |
|---|
| 7 | License as published by the Free Software Foundation; either |
|---|
| 8 | version 2.1 of the License, or (at your option) any later version. |
|---|
| 9 | |
|---|
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
|---|
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
|---|
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
|---|
| 13 | Lesser General Public License for more details. |
|---|
| 14 | |
|---|
| 15 | You should have received a copy of the GNU Lesser General Public |
|---|
| 16 | License along with the GNU C Library; if not, see |
|---|
| 17 | <https://www.gnu.org/licenses/>. */ |
|---|
| 18 | |
|---|
| 19 | #include <errno.h> |
|---|
| 20 | #include <unistd.h> |
|---|
| 21 | #include <sys/mman.h> |
|---|
| 22 | #include <sysdep.h> |
|---|
| 23 | #include <mmap_internal.h> |
|---|
| 24 | |
|---|
| 25 | #ifdef __NR_mmap2 |
|---|
| 26 | /* To avoid silent truncation of offset when using mmap2, do not accept |
|---|
| 27 | offset larger than 1 << (page_shift + off_t bits). For archictures with |
|---|
| 28 | 32 bits off_t and page size of 4096 it would be 1^44. */ |
|---|
| 29 | # define MMAP_OFF_HIGH_MASK \ |
|---|
| 30 | ((-(MMAP2_PAGE_UNIT << 1) << (8 * sizeof (off_t) - 1))) |
|---|
| 31 | #else |
|---|
| 32 | /* Some ABIs might use __NR_mmap while having sizeof (off_t) smaller than |
|---|
| 33 | sizeof (off64_t) (currently only MIPS64n32). For this case just set |
|---|
| 34 | zero the higher bits so mmap with large offset does not fail. */ |
|---|
| 35 | # define MMAP_OFF_HIGH_MASK 0x0 |
|---|
| 36 | #endif |
|---|
| 37 | |
|---|
| 38 | #define MMAP_OFF_MASK (MMAP_OFF_HIGH_MASK | MMAP_OFF_LOW_MASK) |
|---|
| 39 | |
|---|
| 40 | /* An architecture may override this. */ |
|---|
| 41 | #ifndef MMAP_PREPARE |
|---|
| 42 | # define MMAP_PREPARE(addr, len, prot, flags, fd, offset) |
|---|
| 43 | #endif |
|---|
| 44 | |
|---|
| 45 | void * |
|---|
| 46 | __mmap64 (void *addr, size_t len, int prot, int flags, int fd, off64_t offset) |
|---|
| 47 | { |
|---|
| 48 | MMAP_CHECK_PAGE_UNIT (); |
|---|
| 49 | |
|---|
| 50 | if (offset & MMAP_OFF_MASK) |
|---|
| 51 | return (void *) INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL); |
|---|
| 52 | |
|---|
| 53 | MMAP_PREPARE (addr, len, prot, flags, fd, offset); |
|---|
| 54 | #ifdef __NR_mmap2 |
|---|
| 55 | return (void *) MMAP_CALL (mmap2, addr, len, prot, flags, fd, |
|---|
| 56 | (off_t) (offset / MMAP2_PAGE_UNIT)); |
|---|
| 57 | #else |
|---|
| 58 | return (void *) MMAP_CALL (mmap, addr, len, prot, flags, fd, offset); |
|---|
| 59 | #endif |
|---|
| 60 | } |
|---|
| 61 | weak_alias (__mmap64, mmap64) |
|---|
| 62 | libc_hidden_def (__mmap64) |
|---|
| 63 | |
|---|
| 64 | #ifdef __OFF_T_MATCHES_OFF64_T |
|---|
| 65 | weak_alias (__mmap64, mmap) |
|---|
| 66 | weak_alias (__mmap64, __mmap) |
|---|
| 67 | libc_hidden_def (__mmap) |
|---|
| 68 | #endif |
|---|
| 69 | |
|---|
