e7db2d3588
This driver can be loaded as an overlay on top of a real block device, and can then be used to generate block-level failures for certain transfer requests. Specifically, a rule-based system allows the user to introduce (overt and silent) data corruption and errors. It exposes itself through /dev/fbd, and a file system can be mounted on top of it. The new fbdctl(8) tool can be used to control the driver; see ``man fbdctl'' for details. It also comes with a test set, located in test/fbdtest.
191 lines
3.0 KiB
C
191 lines
3.0 KiB
C
/* Simple block pattern reader/writer for testing FBD */
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#define BLOCK_SIZE 4096 /* set to match root FS to prevent partial I/O */
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static int flush_buf(int fd, char *buf, size_t size, size_t write_size)
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{
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ssize_t r;
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while (write_size <= size) {
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if ((r = write(fd, buf, write_size)) != write_size) {
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if (r < 0)
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perror("write");
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else
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fprintf(stderr, "short write (%d < %d)\n",
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r, write_size);
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return EXIT_FAILURE;
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}
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sync();
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buf += write_size;
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size -= write_size;
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}
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return EXIT_SUCCESS;
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}
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static int write_pattern(int fd, char *pattern, int write_size)
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{
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char *buf, *ptr;
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size_t size;
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int r, count, nblocks;
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/* Only write sizes that are a multiple or a
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* divisor of the block size, are supported.
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*/
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nblocks = write_size / BLOCK_SIZE;
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if (!nblocks) nblocks = 1;
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size = nblocks * BLOCK_SIZE;
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if ((buf = malloc(size)) == NULL) {
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perror("malloc");
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return EXIT_FAILURE;
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}
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count = 0;
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do {
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ptr = &buf[count * BLOCK_SIZE];
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switch (*pattern) {
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case 'A':
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case 'B':
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case 'C':
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case 'D':
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case 'U':
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memset(ptr, *pattern, BLOCK_SIZE);
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break;
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case '0':
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memset(ptr, 0, BLOCK_SIZE);
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break;
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case '\0':
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memset(ptr, 0, BLOCK_SIZE);
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ptr[0] = 'E';
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ptr[1] = 'O';
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ptr[2] = 'F';
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}
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if (++count == nblocks) {
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if ((r = flush_buf(fd, buf, size, write_size)) !=
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EXIT_SUCCESS) {
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free(buf);
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return r;
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}
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count = 0;
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}
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} while (*pattern++);
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if (count > 0)
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r = flush_buf(fd, buf, count * BLOCK_SIZE, write_size);
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else
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r = EXIT_SUCCESS;
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free(buf);
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return r;
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}
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static int read_pattern(int fd)
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{
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char buf[BLOCK_SIZE];
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unsigned int i, val;
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ssize_t r;
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for (;;) {
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memset(buf, '?', sizeof(buf));
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if ((r = read(fd, buf, sizeof(buf))) != sizeof(buf)) {
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putchar('#');
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if (!r) break; /* stop at hard EOF */
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lseek(fd, sizeof(buf), SEEK_CUR);
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continue;
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}
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if (buf[0] == 'E' && buf[1] == 'O' && buf[2] == 'F') {
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for (i = 3; i < sizeof(buf); i++)
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if (buf[i] != 0) break;
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if (i == sizeof(buf)) break;
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}
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for (i = 1; i < sizeof(buf); i++)
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if (buf[i] != buf[0]) break;
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if (i == sizeof(buf)) {
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switch (buf[0]) {
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case 'A':
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case 'B':
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case 'C':
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case 'D':
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case 'U':
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case '?':
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printf("%c", buf[0]);
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break;
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case '\0':
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printf("0");
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break;
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default:
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printf("X");
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}
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continue;
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}
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for (i = val = 0; i < sizeof(buf); i++)
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val += buf[i];
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printf("%c", 'a' + val % 26);
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}
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printf("\n");
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return EXIT_SUCCESS;
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}
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int main(int argc, char **argv)
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{
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int fd, r;
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if (argc < 2) {
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fprintf(stderr, "usage: %s <device> [pattern [writesz]]\n",
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argv[0]);
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return EXIT_FAILURE;
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}
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fd = open(argv[1], (argc > 2) ? O_WRONLY : O_RDONLY);
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if (fd < 0) {
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perror("open");
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return EXIT_FAILURE;
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}
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if (argc > 2)
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r = write_pattern(fd, argv[2],
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argv[3] ? atoi(argv[3]) : BLOCK_SIZE);
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else
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r = read_pattern(fd);
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close(fd);
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return r;
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}
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