1 /* 2 * Copyright (c) 2017 Red Hat, Inc. 3 * 01/02/2003 Port to LTP avenkat (at) us.ibm.com 4 * 06/30/2001 Port to Linux nsharoff (at) us.ibm.com 5 * 6 * This program is free software: you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation, either version 3 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 /* 20 * Mmap parts of a file, and then write to the file causing single 21 * write requests to jump back and forth between mmaped io and regular io. 22 */ 23 24 #define _GNU_SOURCE 25 #include <stdlib.h> 26 #include "tst_test.h" 27 #include "tst_safe_macros.h" 28 29 #define NUM_PAGES (192) 30 #define TEST_FILE "mmapstress04-testfile" 31 32 static int page_size; 33 static unsigned char *mmap_area; 34 35 static void setup(void) 36 { 37 page_size = getpagesize(); 38 39 /* 40 * Pick large enough area, PROT_NONE doesn't matter, 41 * because we remap it later. 42 */ 43 mmap_area = SAFE_MMAP(NULL, page_size * NUM_PAGES, PROT_NONE, 44 MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); 45 } 46 47 static void write_fully(int fd, void *buf, int len) 48 { 49 int ret; 50 51 do { 52 ret = SAFE_WRITE(0, fd, buf, len); 53 buf += ret; 54 len -= ret; 55 } while (len > 0); 56 } 57 58 static void mmapstress04(void) 59 { 60 int i, j, rofd, rwfd; 61 char *buf; 62 int mapped_pages = 0; 63 64 if (tst_fill_file(TEST_FILE, 'b', page_size, 1)) 65 tst_brk(TBROK | TERRNO, "fill_file"); 66 67 rofd = SAFE_OPEN(TEST_FILE, O_RDONLY | O_CREAT, 0777); 68 /* 69 * Assuming disk blocks are 8k, and logical pages are 4k, there are 70 * two maps per block. In order to test mapping at the beginning and 71 * ends of the block, mapping the whole block, or none of the block 72 * with different mappings on preceding and following blocks, each 73 * 3 blocks with 6 pages can be thought of as a binary number from 0 to 74 * 64 with a bit set for mapped or cleared for unmapped. This number 75 * is represented by i. The value j is used to look at the bits of i 76 * and decided to map the page or not. 77 * NOTE: None of the above assumptions are critical. 78 */ 79 for (i = 0; i < 64; i++) { 80 for (j = 0; j < 6; j++) { 81 off_t mapoff; 82 83 if (!(i & (1 << j))) 84 continue; 85 86 mapoff = page_size * (off_t)(6 * i + j); 87 SAFE_MMAP(mmap_area + page_size * mapped_pages++, 88 page_size, PROT_READ, 89 MAP_FILE | MAP_PRIVATE | MAP_FIXED, 90 rofd, mapoff); 91 } 92 } 93 SAFE_CLOSE(rofd); 94 95 /* write out 6 pages of stuff into each of the 64 six page sections */ 96 rwfd = SAFE_OPEN(TEST_FILE, O_RDWR); 97 buf = SAFE_MALLOC(page_size); 98 memset(buf, 'a', page_size); 99 for (i = 0; i < 6 * 64; i++) 100 write_fully(rwfd, buf, page_size); 101 free(buf); 102 SAFE_CLOSE(rwfd); 103 104 /* 105 * Just finished scribbling all over interwoven mmapped and unmapped 106 * regions. Check the data. 107 */ 108 for (i = 0; i < mapped_pages * page_size; i++) { 109 unsigned char val = *(mmap_area + i); 110 111 if (val != 'a') { 112 tst_res(TFAIL, "unexpected value in map, " 113 "i=%d,val=0x%x", i, val); 114 goto done; 115 } 116 } 117 tst_res(TPASS, "blocks have expected data"); 118 done: 119 SAFE_UNLINK(TEST_FILE); 120 } 121 122 static struct tst_test test = { 123 .tid = "mmapstress04", 124 .needs_tmpdir = 1, 125 .test_all = mmapstress04, 126 .setup = setup, 127 }; 128
