test/fbdtest/rwblocks.c

   1 /* Simple block pattern reader/writer for testing FBD */
   2
   3 #include <stdlib.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7 #include <fcntl.h>
   8
   9 #define BLOCK_SIZE 4096 /* set to match root FS to prevent partial I/O */
  10
  11 static int flush_buf(int fd, char *buf, size_t size, size_t write_size)
  12 {
  13         ssize_t r;
  14
  15         while (write_size <= size) {
  16                 if ((r = write(fd, buf, write_size)) != write_size) {
  17                         if (r < 0)
  18                                 perror("write");
  19                         else
  20                                 fprintf(stderr, "short write (%d < %d)\n",
  21                                         r, write_size);
  22
  23                         return EXIT_FAILURE;
  24                 }
  25
  26                 sync();
  27
  28                 buf += write_size;
  29                 size -= write_size;
  30         }
  31
  32         return EXIT_SUCCESS;
  33 }
  34
  35 static int write_pattern(int fd, char *pattern, int write_size)
  36 {
  37         char *buf, *ptr;
  38         size_t size;
  39         int r, count, nblocks;
  40
  41         /* Only write sizes that are a multiple or a
  42          * divisor of the block size, are supported.
  43          */
  44         nblocks = write_size / BLOCK_SIZE;
  45         if (!nblocks) nblocks = 1;
  46         size = nblocks * BLOCK_SIZE;
  47
  48         if ((buf = malloc(size)) == NULL) {
  49                 perror("malloc");
  50
  51                 return EXIT_FAILURE;
  52         }
  53
  54         count = 0;
  55
  56         do {
  57                 ptr = &buf[count * BLOCK_SIZE];
  58
  59                 switch (*pattern) {
  60                 case 'A':
  61                 case 'B':
  62                 case 'C':
  63                 case 'D':
  64                 case 'U':
  65                         memset(ptr, *pattern, BLOCK_SIZE);
  66                         break;
  67
  68                 case '0':
  69                         memset(ptr, 0, BLOCK_SIZE);
  70                         break;
  71
  72                 case '\0':
  73                         memset(ptr, 0, BLOCK_SIZE);
  74                         ptr[0] = 'E';
  75                         ptr[1] = 'O';
  76                         ptr[2] = 'F';
  77                 }
  78
  79                 if (++count == nblocks) {
  80                         if ((r = flush_buf(fd, buf, size, write_size)) !=
  81                                         EXIT_SUCCESS) {
  82                                 free(buf);
  83
  84                                 return r;
  85                         }
  86
  87                         count = 0;
  88                 }
  89         } while (*pattern++);
  90
  91         if (count > 0)
  92                 r = flush_buf(fd, buf, count * BLOCK_SIZE, write_size);
  93         else
  94                 r = EXIT_SUCCESS;
  95
  96         free(buf);
  97
  98         return r;
  99 }
 100
 101 static int read_pattern(int fd)
 102 {
 103         char buf[BLOCK_SIZE];
 104         unsigned int i, val;
 105         ssize_t r;
 106
 107         for (;;) {
 108                 memset(buf, '?', sizeof(buf));
 109
 110                 if ((r = read(fd, buf, sizeof(buf))) != sizeof(buf)) {
 111                         putchar('#');
 112
 113                         if (!r) break; /* stop at hard EOF */
 114
 115                         lseek(fd, sizeof(buf), SEEK_CUR);
 116
 117                         continue;
 118                 }
 119
 120                 if (buf[0] == 'E' && buf[1] == 'O' && buf[2] == 'F') {
 121                         for (i = 3; i < sizeof(buf); i++)
 122                                 if (buf[i] != 0) break;
 123
 124                         if (i == sizeof(buf)) break;
 125                 }
 126
 127                 for (i = 1; i < sizeof(buf); i++)
 128                         if (buf[i] != buf[0]) break;
 129
 130                 if (i == sizeof(buf)) {
 131                         switch (buf[0]) {
 132                         case 'A':
 133                         case 'B':
 134                         case 'C':
 135                         case 'D':
 136                         case 'U':
 137                         case '?':
 138                                 printf("%c", buf[0]);
 139                                 break;
 140
 141                         case '\0':
 142                                 printf("0");
 143                                 break;
 144
 145                         default:
 146                                 printf("X");
 147                         }
 148
 149                         continue;
 150                 }
 151
 152                 for (i = val = 0; i < sizeof(buf); i++)
 153                         val += buf[i];
 154
 155                 printf("%c", 'a' + val % 26);
 156         }
 157
 158         printf("\n");
 159
 160         return EXIT_SUCCESS;
 161 }
 162
 163 int main(int argc, char **argv)
 164 {
 165         int fd, r;
 166
 167         if (argc < 2) {
 168                 fprintf(stderr, "usage: %s <device> [pattern [writesz]]\n",
 169                         argv[0]);
 170
 171                 return EXIT_FAILURE;
 172         }
 173
 174         fd = open(argv[1], (argc > 2) ? O_WRONLY : O_RDONLY);
 175         if (fd < 0) {
 176                 perror("open");
 177
 178                 return EXIT_FAILURE;
 179         }
 180
 181         if (argc > 2)
 182                 r = write_pattern(fd, argv[2],
 183                         argv[3] ? atoi(argv[3]) : BLOCK_SIZE);
 184         else
 185                 r = read_pattern(fd);
 186
 187         close(fd);
 188
 189         return r;
 190 }