mmap-file.c 1.8 KB

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  1. #include <sys/mman.h>
  2. #include <sys/wait.h>
  3. #include <sys/types.h>
  4. #include <stdio.h>
  5. #include <unistd.h>
  6. #include <signal.h>
  7. #include <stdlib.h>
  8. const char * message;
  9. void SIGBUS_handler (int sig)
  10. {
  11. puts(message);
  12. exit(0);
  13. }
  14. int main (int argc, const char ** argv)
  15. {
  16. int rv;
  17. /* Initalization: create a 1025-byte file */
  18. FILE * fp = fopen("testfile","w+");
  19. if (!fp) {
  20. perror("fopen"); return 1;
  21. }
  22. rv = ftruncate(fileno(fp), 1024);
  23. if (rv) {
  24. perror ("ftruncate"); return 1;
  25. }
  26. volatile unsigned char * a
  27. = mmap(NULL, 9162, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FILE, fileno(fp), 0);
  28. if (a == MAP_FAILED) {
  29. perror("mmap"); return 1;
  30. }
  31. a[1023] = 0xff;
  32. a[4095] = 0xff;
  33. asm volatile ("nop" ::: "memory");
  34. int pid = fork();
  35. if (pid == -1) {
  36. perror("fork"); return 1;
  37. }
  38. if (pid != 0) {
  39. rv = waitpid(pid, NULL, 0);
  40. if (rv == -1) {
  41. perror("waitpid"); return 1;
  42. }
  43. }
  44. asm volatile ("nop" ::: "memory");
  45. a[ 0] = 0xff;
  46. printf(pid == 0 ? "mmap test 1 passed\n" : "mmap test 6 passed\n");
  47. a[1024] = 0xff;
  48. printf(pid == 0 ? "mmap test 2 passed\n" : "mmap test 7 passed\n");
  49. asm volatile ("nop" ::: "memory");
  50. if (pid == 0) {
  51. if (a[1023] == 0xff)
  52. printf("mmap test 3 passed\n");
  53. if (a[4095] == 0xff)
  54. printf("mmap test 4 passed\n");
  55. }
  56. asm volatile ("nop" ::: "memory");
  57. if (signal(SIGBUS, SIGBUS_handler) == SIG_ERR) {
  58. perror("signal"); return 1;
  59. }
  60. message = pid == 0 ? "mmap test 5 passed\n" : "mmap test 8 passed\n";
  61. a[4096] = 0xff;
  62. if (signal(SIGBUS, SIG_DFL) == SIG_ERR) {
  63. perror("signal"); return 1;
  64. }
  65. return 0;
  66. }