/* (c) John Berthels 2005 <jjberthels@gmail.com>. See COPYING for license */#include <stdlib.h>#include <sys/types.h>#include <sys/wait.h>#include <sys/mman.h> /* For mmap() */#include <sys/fcntl.h> /* For open flags */#include <unistd.h> /* For getopt */#include <stdio.h>#include "pagesize.h"enum MapType {     PRIVATE,     SHARED};enum WorkType {     READ,     WRITE,     JUSTMAP};static int create_fill_file(const char *fname, int size){     int i;     FILE *fp = fopen(fname, "w+");     if (fp == NULL) {	  perror("fopen failed");	  return -1;     }     for (i = 0; i < size; ++i) {	  fputc('A', fp);     }     fflush(fp);     fsync(fileno(fp));     fclose(fp);     return 0;}static void *make_map(const char *fname,		      void *map_at,		      int map_size,		      enum WorkType wt,		      enum MapType mt){     int fd = -1;     int mmap_flags;     int mmap_prot;     void *p = NULL;     switch (mt) {     case PRIVATE:	  mmap_flags = MAP_PRIVATE;	  break;     case SHARED:	  mmap_flags = MAP_SHARED;	  break;     default:	  fprintf(stderr, "Invalid map flags\n");	  goto Err;     }     switch (wt) {     case READ:	  mmap_prot = PROT_READ;	  break;     case WRITE:	  mmap_prot = PROT_READ | PROT_WRITE;	  break;     case JUSTMAP:	  mmap_prot = PROT_READ | PROT_WRITE;	  break;     default:	  fprintf(stderr, "Invalid map flags\n");	  goto Err;     }          /* Null fname is used to signal anonymous map */     if (fname != NULL) {	  fd = open(fname, O_RDWR);	  if (fd < 0) {	       perror("open failed");	       goto Err;	  }     }     else {	  mmap_flags |= MAP_ANONYMOUS;     }     if (map_at != NULL) {	  mmap_flags |= MAP_FIXED;     }          p = mmap(map_at,	      map_size,	      mmap_prot,	      mmap_flags,	      fd,	      0);     /* printf("pid %d mmap returned %p\n", getpid(), p); */     if (p == MAP_FAILED) {	  perror("mmap failed");	  goto Err;     }     if (map_at != NULL && p != map_at) {	  fprintf(stderr, "can't map at required address [%p] got [%p]\n",		  map_at, p);	  goto Err;     }     return p;Err:     if (fd >= 0) {	  close(fd);     }     if (p != MAP_FAILED) {	  munmap(p, map_size);     }     return MAP_FAILED;}static int do_work(char *p, int map_size, enum WorkType wt, enum MapType mt){     int i;     int sum = 0;     pid_t pid = getpid();     for (i = 0; i < map_size; ++i) {	  switch (wt) {	  case READ:	       sum += p[i];	       sum %= 10;	       break;	  case WRITE:	       p[i] = pid % 100;	       break;	  case JUSTMAP:	       break;	  default:	       fprintf(stderr, "Invalid work type\n");	       return -1;	  }     }          return 0;}static void wait_for_all_children(void){     int rc, status;     do {	  rc = wait(&status);     }     while (rc > 0);}/* * fork n copies, each copy then mmap's a file and twiddles it. */int main(int argc, char **argv){     char *fname = NULL;     int num_pages = 100, num_children = 5, sleep_secs = 60;     enum WorkType wt = READ;     enum MapType mt = SHARED;     char opt;     int pid, map_size;     void *p = MAP_FAILED;     void *map_at = NULL;     int shared_anon_map = 0;          while ((opt = getopt(argc, argv, "a:PSrwmf:p:n:s:")) > 0) {	  switch(opt) {	  case 'a': /* map at this address */	       sscanf(optarg, "%p", &map_at);	       if (map_at == NULL) {		    fprintf(stderr, "Bad ptr argument for map at [%s]\n", optarg);	       }	       break;	  case 'r':	       wt = READ;	       break;	  case 'w':	       wt = WRITE;	       break;	  case 'm':	       wt = JUSTMAP;	       break;	  case 'P':	       mt = PRIVATE;	       break;	  case 'S':	       mt = SHARED;	       break;	  case 's':	       sleep_secs = atoi(optarg);	       break;	  case 'f':	       fname = optarg;	       break;	  case 'p':	       num_pages = atoi(optarg);	       break;	  case 'n':	       num_children = atoi(optarg);	       break;	  case ':':	       fprintf(stderr, "Missing argument to option '%c'\n", opt);	       return -1;	  case '?':	       fprintf(stderr, "Unrecognised option '%c'\n", opt);	       return -1;	  default:	       fprintf(stderr, "Error processing options [%d:%c]\n", opt, opt);	       return -1;	  }     }     map_size = CURRENT_PAGE_SIZE * num_pages;     shared_anon_map = (fname == NULL && mt == SHARED);          if (fname != NULL) {	  /* Create file before we fork off */	  create_fill_file(fname, map_size);     }     if (shared_anon_map) {	  /* Shared anon maps must be created by the parent */	  p = make_map(fname, map_at, map_size, wt, mt);     }          do {	  pid = fork();     }     while (pid != 0 && --num_children > 0);     if (pid == 0) {	  /* child */	  if (p == MAP_FAILED) {	       p = make_map(fname, map_at, map_size, wt, mt);	  }	  if (p == MAP_FAILED) {	       fprintf(stderr, "Failed to create map\n");	       return -1;	  }	  if (do_work(p, map_size, wt, mt) < 0) {	       fprintf(stderr, "Error touching map\n");	       return -1;	  }	  if (sleep_secs > 0) {	       sleep(sleep_secs);	  }     }     else {	  /* parent */	  if (shared_anon_map) {	       /* should really have a short pause here...children are racing */	       /* For measuring/testing, only the children should have the map */	       munmap(map_at, map_size);	  }	  wait_for_all_children();	  unlink(fname);     }     return 0;}