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/* Simple block pattern reader/writer for testing FBD */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#define BLOCK_SIZE 4096 /* set to match root FS to prevent partial I/O */
static int flush_buf(int fd, char *buf, size_t size, size_t write_size)
{
ssize_t r;
while (write_size <= size) {
if ((r = write(fd, buf, write_size)) != write_size) {
if (r < 0)
perror("write");
else
fprintf(stderr, "short write (%d < %d)\n",
r, write_size);
return EXIT_FAILURE;
}
sync();
buf += write_size;
size -= write_size;
}
return EXIT_SUCCESS;
}
static int write_pattern(int fd, char *pattern, int write_size)
{
char *buf, *ptr;
size_t size;
int r, count, nblocks;
/* Only write sizes that are a multiple or a
* divisor of the block size, are supported.
*/
nblocks = write_size / BLOCK_SIZE;
if (!nblocks) nblocks = 1;
size = nblocks * BLOCK_SIZE;
if ((buf = malloc(size)) == NULL) {
perror("malloc");
return EXIT_FAILURE;
}
count = 0;
do {
ptr = &buf[count * BLOCK_SIZE];
switch (*pattern) {
case 'A':
case 'B':
case 'C':
case 'D':
case 'U':
memset(ptr, *pattern, BLOCK_SIZE);
break;
case '0':
memset(ptr, 0, BLOCK_SIZE);
break;
case '\0':
memset(ptr, 0, BLOCK_SIZE);
ptr[0] = 'E';
ptr[1] = 'O';
ptr[2] = 'F';
}
if (++count == nblocks) {
if ((r = flush_buf(fd, buf, size, write_size)) !=
EXIT_SUCCESS) {
free(buf);
return r;
}
count = 0;
}
} while (*pattern++);
if (count > 0)
r = flush_buf(fd, buf, count * BLOCK_SIZE, write_size);
else
r = EXIT_SUCCESS;
free(buf);
return r;
}
static int read_pattern(int fd)
{
char buf[BLOCK_SIZE];
unsigned int i, val;
ssize_t r;
for (;;) {
memset(buf, '?', sizeof(buf));
if ((r = read(fd, buf, sizeof(buf))) != sizeof(buf)) {
putchar('#');
if (!r) break; /* stop at hard EOF */
lseek(fd, sizeof(buf), SEEK_CUR);
continue;
}
if (buf[0] == 'E' && buf[1] == 'O' && buf[2] == 'F') {
for (i = 3; i < sizeof(buf); i++)
if (buf[i] != 0) break;
if (i == sizeof(buf)) break;
}
for (i = 1; i < sizeof(buf); i++)
if (buf[i] != buf[0]) break;
if (i == sizeof(buf)) {
switch (buf[0]) {
case 'A':
case 'B':
case 'C':
case 'D':
case 'U':
case '?':
printf("%c", buf[0]);
break;
case '\0':
printf("0");
break;
default:
printf("X");
}
continue;
}
for (i = val = 0; i < sizeof(buf); i++)
val += buf[i];
printf("%c", 'a' + val % 26);
}
printf("\n");
return EXIT_SUCCESS;
}
int main(int argc, char **argv)
{
int fd, r;
if (argc < 2) {
fprintf(stderr, "usage: %s <device> [pattern [writesz]]\n",
argv[0]);
return EXIT_FAILURE;
}
fd = open(argv[1], (argc > 2) ? O_WRONLY : O_RDONLY);
if (fd < 0) {
perror("open");
return EXIT_FAILURE;
}
if (argc > 2)
r = write_pattern(fd, argv[2],
argv[3] ? atoi(argv[3]) : BLOCK_SIZE);
else
r = read_pattern(fd);
close(fd);
return r;
}
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