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3666a048 | 1 | /* Copyright 1992-2021 Free Software Foundation, Inc. |
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2 | |
3 | This file is part of GDB. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program 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 | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | /* This test has two large memory areas buf_rw and buf_ro. | |
19 | ||
20 | buf_rw is written to by the program while buf_ro is initialized at | |
21 | compile / load time. Thus, when a core file is created, buf_rw's | |
22 | memory should reside in the core file, but buf_ro probably won't be. | |
23 | Instead, the contents of buf_ro are available from the executable. | |
24 | ||
25 | Now, for the wrinkle: We create a one page read-only mapping over | |
26 | both of these areas. This will create a one page "hole" of all | |
27 | zeros in each area. | |
28 | ||
29 | Will GDB be able to correctly read memory from each of the four | |
30 | (or six, if you count the regions on the other side of each hole) | |
31 | memory regions? */ | |
32 | ||
33 | #include <stdio.h> | |
34 | #include <sys/types.h> | |
35 | #include <fcntl.h> | |
36 | #include <sys/mman.h> | |
37 | #include <signal.h> | |
38 | #include <stdlib.h> | |
39 | #include <unistd.h> | |
40 | #include <string.h> | |
41 | #include <errno.h> | |
0245e136 | 42 | #include <inttypes.h> |
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43 | |
44 | /* These are globals so that we can find them easily when debugging | |
45 | the core file. */ | |
46 | long pagesize; | |
0245e136 | 47 | uintptr_t addr; |
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48 | char *mbuf_ro; |
49 | char *mbuf_rw; | |
50 | ||
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51 | /* 256 KiB buffer. */ |
52 | char buf_rw[256 * 1024]; | |
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53 | |
54 | #define C5_16 \ | |
55 | 0xc5, 0xc5, 0xc5, 0xc5, \ | |
56 | 0xc5, 0xc5, 0xc5, 0xc5, \ | |
57 | 0xc5, 0xc5, 0xc5, 0xc5, \ | |
58 | 0xc5, 0xc5, 0xc5, 0xc5 | |
59 | ||
60 | #define C5_256 \ | |
61 | C5_16, C5_16, C5_16, C5_16, \ | |
62 | C5_16, C5_16, C5_16, C5_16, \ | |
63 | C5_16, C5_16, C5_16, C5_16, \ | |
64 | C5_16, C5_16, C5_16, C5_16 | |
65 | ||
66 | #define C5_1k \ | |
67 | C5_256, C5_256, C5_256, C5_256 | |
68 | ||
9ef1ec5d | 69 | #define C5_8k \ |
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70 | C5_1k, C5_1k, C5_1k, C5_1k, \ |
71 | C5_1k, C5_1k, C5_1k, C5_1k | |
72 | ||
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73 | #define C5_64k \ |
74 | C5_8k, C5_8k, C5_8k, C5_8k, \ | |
75 | C5_8k, C5_8k, C5_8k, C5_8k | |
76 | ||
77 | #define C5_256k \ | |
78 | C5_64k, C5_64k, C5_64k, C5_64k | |
79 | ||
80 | /* 256 KiB worth of data. For this test case, we can't allocate a | |
81 | buffer and then fill it; we want GDB to have to read this data | |
82 | from the executable; it should NOT find it in the core file. */ | |
83 | ||
84 | const char buf_ro[] = { C5_256k }; | |
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85 | |
86 | int | |
87 | main (int argc, char **argv) | |
88 | { | |
89 | int i, bitcount; | |
90 | ||
91 | #ifdef _SC_PAGESIZE | |
92 | pagesize = sysconf (_SC_PAGESIZE); | |
93 | #else | |
94 | pagesize = 8192; | |
95 | #endif | |
96 | ||
97 | /* Verify that pagesize is a power of 2. */ | |
98 | bitcount = 0; | |
99 | for (i = 0; i < 4 * sizeof (pagesize); i++) | |
100 | if (pagesize & (1 << i)) | |
101 | bitcount++; | |
102 | ||
103 | if (bitcount != 1) | |
104 | { | |
105 | fprintf (stderr, "pagesize is not a power of 2.\n"); | |
106 | exit (1); | |
107 | } | |
108 | ||
109 | /* Compute an address that should be within buf_ro. Complain if not. */ | |
0245e136 | 110 | addr = ((uintptr_t) buf_ro + pagesize) & ~(pagesize - 1); |
7da515fd | 111 | |
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112 | if (addr <= (uintptr_t) buf_ro |
113 | || addr >= (uintptr_t) buf_ro + sizeof (buf_ro)) | |
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114 | { |
115 | fprintf (stderr, "Unable to compute a suitable address within buf_ro.\n"); | |
116 | exit (1); | |
117 | } | |
118 | ||
119 | mbuf_ro = mmap ((void *) addr, pagesize, PROT_READ, | |
120 | MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); | |
121 | ||
122 | if (mbuf_ro == MAP_FAILED) | |
123 | { | |
124 | fprintf (stderr, "mmap #1 failed: %s.\n", strerror (errno)); | |
125 | exit (1); | |
126 | } | |
127 | ||
128 | /* Write (and fill) the R/W region. */ | |
129 | for (i = 0; i < sizeof (buf_rw); i++) | |
130 | buf_rw[i] = 0x6b; | |
131 | ||
132 | /* Compute an mmap address within buf_rw. Complain if it's somewhere | |
133 | else. */ | |
0245e136 | 134 | addr = ((uintptr_t) buf_rw + pagesize) & ~(pagesize - 1); |
7da515fd | 135 | |
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136 | if (addr <= (uintptr_t) buf_rw |
137 | || addr >= (uintptr_t) buf_rw + sizeof (buf_rw)) | |
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138 | { |
139 | fprintf (stderr, "Unable to compute a suitable address within buf_rw.\n"); | |
140 | exit (1); | |
141 | } | |
142 | ||
143 | mbuf_rw = mmap ((void *) addr, pagesize, PROT_READ, | |
144 | MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); | |
145 | ||
146 | if (mbuf_rw == MAP_FAILED) | |
147 | { | |
148 | fprintf (stderr, "mmap #2 failed: %s.\n", strerror (errno)); | |
149 | exit (1); | |
150 | } | |
151 | ||
152 | /* With correct ulimit, etc. this should cause a core dump. */ | |
153 | abort (); | |
154 | } |