testing/mmap.c

   1
   2 #include <stdio.h>
   3 #include <comedilib.h>
   4 #include <fcntl.h>
   5 #include <unistd.h>
   6 #include <sys/ioctl.h>
   7 #include <errno.h>
   8 #include <getopt.h>
   9 #include <ctype.h>
  10 #include <math.h>
  11 #include <sys/time.h>
  12 #include <string.h>
  13 #include <sys/mman.h>
  14 #include <signal.h>
  15 #include <setjmp.h>
  16 #include <stdlib.h>
  17
  18 #include "comedi_test.h"
  19
  20 /* XXX this should come from elsewhere */
  21 #define PAGE_SIZE 4096
  22
  23 #define N_SAMPLES 10000
  24
  25 sigjmp_buf jump_env;
  26
  27 void segv_handler(int num)
  28 {
  29         siglongjmp(jump_env,1);
  30 }
  31
  32 int test_segfault(void *memptr)
  33 {
  34         volatile char tmp;
  35         int ret;
  36         struct sigaction act;
  37         struct sigaction oldact;
  38
  39         memset(&act,0,sizeof(act));
  40         act.sa_handler=&segv_handler;
  41         ret = sigaction(SIGSEGV,&act,&oldact);
  42         if(ret)
  43         {
  44                 fprintf(stderr, "sigaction failed\n");
  45                 return 0;
  46         }
  47         ret=sigsetjmp(jump_env, 1);
  48         if(!ret) tmp = *((char *)(memptr));
  49         sigaction(SIGSEGV,&oldact,NULL);
  50         return ret;
  51 }
  52
  53 int test_mmap(void)
  54 {
  55         comedi_cmd cmd;
  56         unsigned char *buf;
  57         unsigned int chanlist[1];
  58         int go;
  59         int fails;
  60         int total=0;
  61         int ret;
  62         void *b;
  63         unsigned char *adr;
  64         unsigned char *map;
  65         unsigned int flags;
  66         int i;
  67         unsigned sample_size;
  68         unsigned map_len;
  69
  70         flags = comedi_get_subdevice_flags(device,subdevice);
  71
  72         if(!(flags&SDF_CMD) || (comedi_get_read_subdevice(device)!=subdevice)){
  73                 printf("not applicable\n");
  74                 return 0;
  75         }
  76         if(flags & SDF_LSAMPL) sample_size = sizeof(lsampl_t);
  77         else sample_size = sizeof(sampl_t);
  78         map_len = sample_size * N_SAMPLES;
  79
  80         if(comedi_get_cmd_generic_timed(device, subdevice, &cmd, 1, 1)<0){
  81                 printf("E: comedi_get_cmd_generic_timed failed\n");
  82                 return 0;
  83         }
  84
  85         buf=malloc(sample_size * N_SAMPLES);
  86
  87         map = mmap(NULL, map_len,PROT_READ, MAP_SHARED, comedi_fileno(device),0);
  88         if(!map){
  89                 printf("E: mmap() failed\n");
  90                 return 0;
  91         }
  92
  93         /* test readability */
  94         for(adr = map; adr < map + map_len; adr += PAGE_SIZE){
  95                 ret=test_segfault(adr);
  96                 if(ret){
  97                         printf("E: %p failed\n",adr);
  98                 }else{
  99                         printf("%p ok\n",adr);
 100                 }
 101         }
 102
 103         if(realtime)cmd.flags |= TRIG_RT;
 104
 105         cmd.chanlist = chanlist;
 106         cmd.scan_end_arg = 1;
 107         cmd.stop_arg = N_SAMPLES;
 108         cmd.chanlist_len = 1;
 109         chanlist[0] = CR_PACK(0,0,0);
 110
 111         comedi_command(device,&cmd);
 112
 113         go=1;
 114         b=buf;
 115         while(go){
 116                 ret = read(comedi_fileno(device), b,
 117                                 (N_SAMPLES * sample_size) - total);
 118                 if(ret<0){
 119                         if(errno==EAGAIN){
 120                                 usleep(10000);
 121                         }else{
 122                                 go = 0;
 123                                 perror("read");
 124                         }
 125                 }else if(ret==0){
 126                         go = 0;
 127                 }else{
 128                         total += ret;
 129                         b += ret;
 130                         if(verbose) printf("read %d %d\n",ret,total);
 131                         if(total >= (N_SAMPLES * sample_size)){
 132                                 go = 0;
 133                         }
 134                 }
 135         }
 136
 137         fails = 0;
 138         for(i=0;i<total;i++){
 139                 if(buf[i]!=map[i]){
 140                         if(fails==0)printf("E: mmap compare failed\n");
 141                         printf("offset %d (read=%02x mmap=%02x)\n",i,
 142                                 buf[i], map[i]);
 143                         fails++;
 144                         if(fails>10)break;
 145                 }
 146         }
 147         if(fails==0) printf("compare ok\n");
 148
 149         munmap(map, map_len);
 150
 151         /* test if area is really unmapped */
 152         for(adr = map; adr < map + map_len; adr += PAGE_SIZE){
 153                 ret=test_segfault(adr);
 154                 if(ret){
 155                         printf("%p segfaulted (ok)\n",adr);
 156                 }else{
 157                         printf("E: %p still mapped\n",adr);
 158                 }
 159         }
 160
 161         free(buf);
 162
 163         return 0;
 164 }
 165