projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 0ecb606c | 1 | /* Copyright (C) 2004, 2005 Free Software Foundation, Inc. |
| b5cc329c UD |
2 | This file is part of the GNU C Library. |
| 3 | ||
| 4 | The GNU C Library is free software; you can redistribute it and/or | |
| 5 | modify it under the terms of the GNU Lesser General Public | |
| 6 | License as published by the Free Software Foundation; either | |
| 7 | version 2.1 of the License, or (at your option) any later version. | |
| 8 | ||
| 9 | The GNU C Library is distributed in the hope that it will be useful, | |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 12 | Lesser General Public License for more details. | |
| 13 | ||
| 14 | You should have received a copy of the GNU Lesser General Public | |
| 15 | License along with the GNU C Library; if not, write to the Free | |
| 16 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
| 17 | 02111-1307 USA. */ | |
| 18 | ||
| 0ecb606c | 19 | #include <errno.h> |
| b5cc329c UD |
20 | #include <stdint.h> |
| 21 | #include <stdio.h> | |
| 22 | #include <stdio_ext.h> | |
| 23 | #include <stdlib.h> | |
| 24 | #include <string.h> | |
| 25 | #include "libio/libioP.h" | |
| 26 | ||
| 27 | /* Return 1 if the whole area PTR .. PTR+SIZE is not writable. | |
| 28 | Return -1 if it is writable. */ | |
| 29 | ||
| 30 | int | |
| 31 | __readonly_area (const char *ptr, size_t size) | |
| 32 | { | |
| 33 | const void *ptr_end = ptr + size; | |
| 34 | ||
| 35 | FILE *fp = fopen ("/proc/self/maps", "rc"); | |
| 36 | if (fp == NULL) | |
| 0ecb606c JJ |
37 | { |
| 38 | /* It is the system administrator's choice to not have /proc | |
| 39 | available to this process (e.g., because it runs in a chroot | |
| 40 | environment. Don't fail in this case. */ | |
| 41 | if (errno == ENOENT | |
| 42 | /* The kernel has a bug in that a process is denied access | |
| 43 | to the /proc filesystem if it is set[ug]id. There has | |
| 44 | been no willingness to change this in the kernel so | |
| 45 | far. */ | |
| 46 | || errno == EACCES) | |
| 47 | return 1; | |
| 48 | return -1; | |
| 49 | } | |
| b5cc329c UD |
50 | |
| 51 | /* We need no locking. */ | |
| 52 | __fsetlocking (fp, FSETLOCKING_BYCALLER); | |
| 53 | ||
| 54 | char *line = NULL; | |
| 55 | size_t linelen = 0; | |
| 56 | ||
| 57 | while (! feof_unlocked (fp)) | |
| 58 | { | |
| 59 | if (_IO_getdelim (&line, &linelen, '\n', fp) <= 0) | |
| 60 | break; | |
| 61 | ||
| 62 | char *p; | |
| 63 | uintptr_t from = strtoul (line, &p, 16); | |
| 64 | ||
| 65 | if (p == line || *p++ != '-') | |
| 66 | break; | |
| 67 | ||
| 68 | char *q; | |
| 69 | uintptr_t to = strtoul (p, &q, 16); | |
| 70 | ||
| 71 | if (q == p || *q++ != ' ') | |
| 72 | break; | |
| 73 | ||
| 74 | if (from < (uintptr_t) ptr_end && to > (uintptr_t) ptr) | |
| 75 | { | |
| 76 | /* Found an entry that at least partially covers the area. */ | |
| 77 | if (*q++ != 'r' || *q++ != '-') | |
| 78 | break; | |
| 79 | ||
| 80 | if (from <= (uintptr_t) ptr && to >= (uintptr_t) ptr_end) | |
| 81 | { | |
| 82 | size = 0; | |
| 83 | break; | |
| 84 | } | |
| 85 | else if (from <= (uintptr_t) ptr) | |
| 86 | size -= to - (uintptr_t) ptr; | |
| 87 | else if (to >= (uintptr_t) ptr_end) | |
| 88 | size -= (uintptr_t) ptr_end - from; | |
| 89 | else | |
| 90 | size -= to - from; | |
| 91 | ||
| 92 | if (!size) | |
| 93 | break; | |
| 94 | } | |
| 95 | } | |
| 96 | ||
| 97 | fclose (fp); | |
| 98 | free (line); | |
| 99 | ||
| 100 | /* If the whole area between ptr and ptr_end is covered by read-only | |
| 101 | VMAs, return 1. Otherwise return -1. */ | |
| 102 | return size == 0 ? 1 : -1; | |
| 103 | } |