1 /* 2 * Copyright (c) 2002, Intel Corporation. All rights reserved. 3 * Copyright (c) 2012, Cyril Hrubis <chrubis (at) suse.cz> 4 * 5 * This file is licensed under the GPL license. For the full content 6 * of this license, see the COPYING file at the top level of this 7 * source tree. 8 * 9 * MAP_SHARED and MAP_PRIVATE describe the disposition of write references 10 * to the memory object. If MAP_SHARED is specified, write references shall 11 * change the underlying object. If MAP_PRIVATE is specified, modifications 12 * to the mapped data by the calling process shall be visible only to the 13 * calling process and shall not change the underlying object. 14 * It is unspecified whether modifications to the underlying object done 15 * after the MAP_PRIVATE mapping is established are visible through 16 * the MAP_PRIVATE mapping. 17 * 18 * Test Steps: 19 * 20 * 1. Create a shared memory object. 21 * 2. mmap the shared memory object into memory, setting MAP_PRIVATE. 22 * 3. Modify the mapped memory. 23 * 4. Fork a child process. 24 * 5. Child process mmap the same shared memory object into memory. 25 * 6. Check whether the change in step 3 is visible to the child. 26 * 27 */ 28 29 #define _XOPEN_SOURCE 600 30 #include <stdio.h> 31 #include <stdlib.h> 32 #include <unistd.h> 33 #include <sys/mman.h> 34 #include <sys/types.h> 35 #include <sys/stat.h> 36 #include <sys/wait.h> 37 #include <fcntl.h> 38 #include <string.h> 39 #include <errno.h> 40 #include "posixtest.h" 41 42 int main(void) 43 { 44 char tmpfname[256]; 45 void *pa; 46 size_t size = 1024; 47 int fd; 48 pid_t child; 49 int exit_stat; 50 51 /* Create shared object */ 52 snprintf(tmpfname, sizeof(tmpfname), "pts_mmap_7_3_%d", getpid()); 53 shm_unlink(tmpfname); 54 fd = shm_open(tmpfname, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR); 55 if (fd == -1) { 56 printf("Error at shm_open(): %s\n", strerror(errno)); 57 return PTS_UNRESOLVED; 58 } 59 shm_unlink(tmpfname); 60 61 if (ftruncate(fd, size) == -1) { 62 printf("Error at ftruncate(): %s\n", strerror(errno)); 63 return PTS_UNRESOLVED; 64 } 65 66 pa = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); 67 if (pa == MAP_FAILED) { 68 printf("Error at mmap(): %s\n", strerror(errno)); 69 return PTS_FAIL; 70 } 71 72 /* Write the mapped memory */ 73 *(char *)pa = 'a'; 74 75 child = fork(); 76 77 switch (child) { 78 case 0: 79 /* Mmap again the same shared memory to child's memory */ 80 pa = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 81 0); 82 if (pa == MAP_FAILED) { 83 printf("Error at mmap(): %s\n", strerror(errno)); 84 return PTS_FAIL; 85 } 86 87 if (*(char *)pa == 'a') { 88 printf("Set flag as MAP_PRIVATE, write reference will " 89 "change the underlying shared memory object\n"); 90 return PTS_FAIL; 91 } 92 93 printf("Set flag as MAP_PRIVATE, write reference will " 94 "not change the underlying shared memory object\n" 95 "Test PASSED\n"); 96 return PTS_PASS; 97 break; 98 case -1: 99 printf("Error at fork(): %s\n", strerror(errno)); 100 return PTS_UNRESOLVED; 101 break; 102 default: 103 waitpid(child, &exit_stat, WUNTRACED); 104 105 close(fd); 106 munmap(pa, size); 107 108 if (WIFEXITED(exit_stat)) { 109 return WEXITSTATUS(exit_stat); 110 } else { 111 printf("Child has not exit properly\n"); 112 return PTS_UNRESOLVED; 113 } 114 } 115 } 116
