diff options
Diffstat (limited to '')
-rw-r--r-- | libraries/eina/src/lib/eina_mmap.c | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/libraries/eina/src/lib/eina_mmap.c b/libraries/eina/src/lib/eina_mmap.c new file mode 100644 index 0000000..fb27bd7 --- /dev/null +++ b/libraries/eina/src/lib/eina_mmap.c | |||
@@ -0,0 +1,185 @@ | |||
1 | /* EINA - EFL data type library | ||
2 | * Copyright (C) 2011 Carsten Haitzler | ||
3 | * | ||
4 | * This 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 | * This 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 this library; | ||
16 | * if not, see <http://www.gnu.org/licenses/>. | ||
17 | */ | ||
18 | |||
19 | #ifdef HAVE_CONFIG_H | ||
20 | # include "config.h" | ||
21 | #endif | ||
22 | |||
23 | #ifdef HAVE_SIGINFO_T | ||
24 | |||
25 | #ifdef STDC_HEADERS | ||
26 | # include <stdlib.h> | ||
27 | # include <stddef.h> | ||
28 | #else | ||
29 | # ifdef HAVE_STDLIB_H | ||
30 | # include <stdlib.h> | ||
31 | # endif | ||
32 | #endif | ||
33 | |||
34 | #include <stdio.h> | ||
35 | #include <stdlib.h> | ||
36 | #include <string.h> | ||
37 | #include <sys/types.h> | ||
38 | #include <sys/stat.h> | ||
39 | #include <sys/mman.h> | ||
40 | #include <limits.h> | ||
41 | #include <signal.h> | ||
42 | #include <errno.h> | ||
43 | #include <fcntl.h> | ||
44 | #include <unistd.h> | ||
45 | |||
46 | #if HAVE_SIGINFO_H | ||
47 | # include <siginfo.h> | ||
48 | #endif | ||
49 | |||
50 | #endif | ||
51 | |||
52 | #include "eina_config.h" | ||
53 | #include "eina_private.h" | ||
54 | #include "eina_log.h" | ||
55 | #include "eina_mmap.h" | ||
56 | |||
57 | /*============================================================================* | ||
58 | * Local * | ||
59 | *============================================================================*/ | ||
60 | |||
61 | static Eina_Bool mmap_safe = EINA_FALSE; | ||
62 | #ifdef HAVE_SIGINFO_T | ||
63 | |||
64 | static int _eina_mmap_log_dom = -1; | ||
65 | static int _eina_mmap_zero_fd = -1; | ||
66 | static long _eina_mmap_pagesize = -1; | ||
67 | |||
68 | #ifdef ERR | ||
69 | #undef ERR | ||
70 | #endif | ||
71 | #define ERR(...) EINA_LOG_DOM_ERR(_eina_mmap_log_dom, __VA_ARGS__) | ||
72 | |||
73 | #ifdef DBG | ||
74 | #undef DBG | ||
75 | #endif | ||
76 | #define DBG(...) EINA_LOG_DOM_DBG(_eina_mmap_log_dom, __VA_ARGS__) | ||
77 | |||
78 | static void | ||
79 | _eina_mmap_safe_sigbus(int sig __UNUSED__, | ||
80 | siginfo_t *siginfo, | ||
81 | void *ptr __UNUSED__) | ||
82 | { | ||
83 | unsigned char *addr = (unsigned char *)(siginfo->si_addr); | ||
84 | int perrno; | ||
85 | |||
86 | /* save previous errno */ | ||
87 | perrno = errno; | ||
88 | /* if problems was an unaligned access - complain accordingly and abort */ | ||
89 | if (siginfo->si_code == BUS_ADRALN) | ||
90 | { | ||
91 | ERR("Unaligned memory access. SIGBUS!!!"); | ||
92 | errno = perrno; | ||
93 | abort(); | ||
94 | } | ||
95 | /* send this to stderr - not eina_log. Specifically want this on stderr */ | ||
96 | fprintf(stderr, | ||
97 | "EINA: Data at address 0x%lx is invalid. Replacing with zero page.\n", | ||
98 | (unsigned long)addr); | ||
99 | /* align address to the lower page boundary */ | ||
100 | addr = (unsigned char *)((long)addr & (~(_eina_mmap_pagesize - 1))); | ||
101 | /* mmap a pzge of zero's from /dev/zero in there */ | ||
102 | if (mmap(addr, _eina_mmap_pagesize, | ||
103 | PROT_READ | PROT_WRITE | PROT_EXEC, | ||
104 | MAP_PRIVATE | MAP_FIXED, | ||
105 | _eina_mmap_zero_fd, 0) == MAP_FAILED) | ||
106 | { | ||
107 | /* mmap of /dev/zero failed :( */ | ||
108 | perror("mmap"); | ||
109 | ERR("Failed to mmap() /dev/zero in place of page. SIGBUS!!!"); | ||
110 | errno = perrno; | ||
111 | abort(); | ||
112 | } | ||
113 | /* restore previous errno */ | ||
114 | errno = perrno; | ||
115 | } | ||
116 | #endif | ||
117 | |||
118 | /*============================================================================* | ||
119 | * API * | ||
120 | *============================================================================*/ | ||
121 | |||
122 | EAPI Eina_Bool | ||
123 | eina_mmap_safety_enabled_set(Eina_Bool enabled) | ||
124 | { | ||
125 | #ifndef HAVE_SIGINFO_T | ||
126 | (void) enabled; | ||
127 | return EINA_FALSE; | ||
128 | #else | ||
129 | if (_eina_mmap_log_dom < 0) | ||
130 | { | ||
131 | _eina_mmap_log_dom = eina_log_domain_register("eina_mmap", | ||
132 | EINA_LOG_COLOR_DEFAULT); | ||
133 | if (_eina_mmap_log_dom < 0) | ||
134 | { | ||
135 | EINA_LOG_ERR("Could not register log domain: eina_mmap"); | ||
136 | return EINA_FALSE; | ||
137 | } | ||
138 | } | ||
139 | |||
140 | enabled = !!enabled; | ||
141 | |||
142 | if (mmap_safe == enabled) return mmap_safe; | ||
143 | if (enabled) | ||
144 | { | ||
145 | struct sigaction sa; | ||
146 | |||
147 | /* find out system page size the cleanest way we can */ | ||
148 | #ifdef _SC_PAGESIZE | ||
149 | _eina_mmap_pagesize = sysconf(_SC_PAGESIZE); | ||
150 | if (_eina_mmap_pagesize <= 0) return EINA_FALSE; | ||
151 | #else | ||
152 | _eina_mmap_pagesize = 4096; | ||
153 | #endif | ||
154 | /* no zero page device - open it */ | ||
155 | if (_eina_mmap_zero_fd < 0) | ||
156 | { | ||
157 | _eina_mmap_zero_fd = open("/dev/zero", O_RDWR); | ||
158 | /* if we don;'t have one - fail to set up mmap safety */ | ||
159 | if (_eina_mmap_zero_fd < 0) return EINA_FALSE; | ||
160 | } | ||
161 | /* set up signal handler for SIGBUS */ | ||
162 | sa.sa_sigaction = _eina_mmap_safe_sigbus; | ||
163 | sa.sa_flags = SA_RESTART | SA_SIGINFO; | ||
164 | sigemptyset(&sa.sa_mask); | ||
165 | if (sigaction(SIGBUS, &sa, NULL) == 0) return EINA_FALSE; | ||
166 | /* setup of SIGBUS handler failed, lets close zero page dev and fail */ | ||
167 | close(_eina_mmap_zero_fd); | ||
168 | _eina_mmap_zero_fd = -1; | ||
169 | return EINA_FALSE; | ||
170 | } | ||
171 | else | ||
172 | { | ||
173 | /* reset signal handler to default for SIGBUS */ | ||
174 | signal(SIGBUS, SIG_DFL); | ||
175 | } | ||
176 | mmap_safe = enabled; | ||
177 | return mmap_safe; | ||
178 | #endif | ||
179 | } | ||
180 | |||
181 | EAPI Eina_Bool | ||
182 | eina_mmap_safety_enabled_get(void) | ||
183 | { | ||
184 | return mmap_safe; | ||
185 | } | ||