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b3dc46ff AB |
1 | /* This testcase is part of GDB, the GNU debugger. |
2 | ||
618f726f | 3 | Copyright 2012-2016 Free Software Foundation, Inc. |
b3dc46ff AB |
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 | #include <stdlib.h> | |
19 | #include <stdio.h> | |
20 | #include <sys/mman.h> | |
21 | #include <unistd.h> | |
22 | #include <string.h> | |
23 | ||
24 | #define CHUNK_SIZE 16000 /* same as findcmd.c's */ | |
25 | ||
26 | void *global_var_0; | |
27 | void *global_var_1; | |
28 | void *global_var_2; | |
29 | ||
30 | void | |
31 | breakpt () | |
32 | { | |
33 | /* Nothing. */ | |
34 | } | |
35 | ||
36 | int | |
37 | main (void) | |
38 | { | |
39 | void *p; | |
40 | size_t pg_size; | |
41 | int pg_count; | |
42 | void *unmapped_page, *last_mapped_page, *first_mapped_page; | |
43 | ||
44 | /* | |
45 | Map enough pages to cover at least CHUNK_SIZE, and one extra page. We | |
46 | then unmap the last page. | |
47 | ||
48 | From gdb we can then perform find commands into unmapped region, gdb | |
49 | should give an error. | |
50 | ||
51 | .-- global_var_0 .-- global_var_1 | |
52 | | | .-- global_var_2 | |
53 | | | | | |
54 | .----.----.----.----.----. | |
55 | | | | | | | | |
56 | '----'----'----'----'----' | |
57 | |<- CHUNK_SIZE ->| | |
58 | ||
59 | If CHUNK_SIZE equals page size then we'll get 3 pages, and if | |
60 | CHUNK_SIZE is less than page size we'll get 2 pages. The test will | |
61 | still work in these cases. | |
62 | ||
63 | (1) We do a find from global_var_0 to global_var_2, this will fail when | |
64 | loading the second chunk, as we know at least CHUNK_SIZE bytes are in | |
65 | mapped space. | |
66 | ||
67 | (2) We do a find from global_var_1 to global_var_2, this will fail when | |
68 | loading the first chunk, assuming the CHUNK_SIZE is at least 16 bytes. | |
69 | ||
70 | (3) We do a find from global_var_2 to (global_var_2 + 16), this too | |
71 | will fail when loading the first chunk regardless of the chunk size. | |
72 | */ | |
73 | ||
74 | pg_size = getpagesize (); | |
75 | /* The +2 ensures the extra page. */ | |
76 | pg_count = CHUNK_SIZE / pg_size + 2; | |
77 | ||
78 | p = mmap (0, pg_count * pg_size, PROT_READ|PROT_WRITE, | |
79 | MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); | |
80 | if (p == MAP_FAILED) | |
81 | { | |
82 | perror ("mmap"); | |
83 | return EXIT_FAILURE; | |
84 | } | |
85 | ||
86 | memset (p, 0, pg_count * pg_size); | |
87 | ||
88 | if (munmap (p + (pg_count - 1) * pg_size, pg_size) == -1) | |
89 | { | |
90 | perror ("munmap"); | |
91 | return EXIT_FAILURE; | |
92 | } | |
93 | ||
94 | first_mapped_page = p; | |
95 | last_mapped_page = p + (pg_count - 2) * pg_size; | |
96 | unmapped_page = last_mapped_page + pg_size; | |
97 | ||
98 | /* Setup global variables we reference from gdb. */ | |
99 | global_var_0 = first_mapped_page; | |
100 | global_var_1 = unmapped_page - 16; | |
101 | global_var_2 = unmapped_page + 16; | |
102 | ||
103 | breakpt (); | |
104 | ||
105 | return EXIT_SUCCESS; | |
106 | } |