| 1 | /* Check that the entire libc.so program image is readable if contiguous. |
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| 2 | Copyright (C) 2025 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <gnu/lib-names.h> |
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| 20 | #include <link.h> |
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| 21 | #include <support/check.h> |
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| 22 | #include <support/xdlfcn.h> |
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| 23 | #include <support/xunistd.h> |
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| 24 | #include <sys/mman.h> |
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| 25 | #include <unistd.h> |
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| 26 | |
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| 27 | static int |
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| 28 | do_test (void) |
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| 29 | { |
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| 30 | struct link_map *l = xdlopen (LIBC_SO, RTLD_NOW); |
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| 31 | |
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| 32 | /* The dynamic loader fills holes with PROT_NONE mappings. */ |
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| 33 | if (!l->l_contiguous) |
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| 34 | FAIL_EXIT1 ("libc.so link map is not contiguous" ); |
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| 35 | |
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| 36 | /* Direct probing does not work because not everything is readable |
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| 37 | due to PROT_NONE mappings. */ |
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| 38 | int pagesize = getpagesize (); |
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| 39 | ElfW(Addr) addr = l->l_map_start; |
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| 40 | TEST_COMPARE (addr % pagesize, 0); |
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| 41 | while (addr < l->l_map_end) |
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| 42 | { |
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| 43 | void *expected = (void *) addr; |
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| 44 | void *ptr = xmmap (addr: expected, length: 1, PROT_READ | PROT_WRITE, |
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| 45 | MAP_PRIVATE | MAP_ANONYMOUS, fd: -1); |
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| 46 | if (ptr == expected) |
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| 47 | FAIL ("hole in libc.so memory image after %lu bytes" , |
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| 48 | (unsigned long int) (addr - l->l_map_start)); |
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| 49 | xmunmap (addr: ptr, length: 1); |
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| 50 | addr += pagesize; |
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| 51 | } |
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| 52 | |
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| 53 | xdlclose (handle: l); |
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| 54 | |
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| 55 | return 0; |
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| 56 | } |
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| 57 | #include <support/test-driver.c> |
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| 58 | |
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