Attachment 918532 Details for Bug 1091866 – Sample code (compile cc -o scrub scrub.c)

Sample code (compile cc -o scrub scrub.c)

scrub.c (text/plain), 2.39 KB, created by John Ferlan on 2014-07-16 21:18:45 UTC

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Filename:

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Creator: John Ferlan

Created: 2014-07-16 21:18:45 UTC

Size: 2.39 KB

patch

obsolete

>#include <stdio.h>
>#include <unistd.h>
>#include <fcntl.h>
>#include <stdlib.h>
>#include <sys/types.h>
>#include <sys/stat.h>
>
>static int
>writezero(int fd, char *writebuf, size_t writebuf_len, off_t extent_len)
>{
>    int written = 0;
>    off_t remaining = 0;
>    size_t write_size = 0;
>    size_t bytes_wiped = 0;
>
>    printf("About to write extent_len=%ld\n", extent_len);
>    remaining = extent_len;
>    while (remaining > 0) {
>        write_size = (writebuf_len < remaining) ? writebuf_len : remaining;
>        //printf("remaining=%lu write_size=%lu", remaining, write_size);
>        written = write(fd, writebuf, write_size);
>        if (written < 0) {
>            fprintf(stderr, "Failed to write %zu bytes", write_size);
>            return -1;
>        }
>        bytes_wiped += written;
>        remaining -= written;
>    }
>    printf("Finished writing %ld bytes\n", bytes_wiped);
>    return bytes_wiped;
>}
>
>int main(int argc, int **argv)
>
>{
>    int fd, rc;
>    struct stat st;
>    char *writebuf;
>
>    if (argc != 3) {
>        fprintf(stderr, "Usage: %s path-to-lv {all|half}\n", argv[0]);
>        exit(EXIT_FAILURE);
>    }
>
>    printf("Open '%s' for scrub\n", argv[1]);
>    fd = open((const char *)argv[1], O_RDWR);
>    if (fd < 0) {
>        fprintf(stderr, "Failed to open storage volume");
>        exit(EXIT_FAILURE);
>    }
>
>    if (fstat(fd, &st) == -1) {
>        fprintf(stderr, "Failed to stat storage volume");
>        close(fd);
>        exit(EXIT_FAILURE);
>    }
>
>    writebuf = calloc(1, st.st_blksize);
>    if (writebuf == NULL) {
>        fprintf(stderr, "Failed to allocate writebuf blksize=%ld",
>                st.st_blksize);
>        close(fd);
>        exit(EXIT_FAILURE);
>    }
>
>    rc = lseek(fd, 0, SEEK_SET);
>    if (rc < 0) {
>        fprintf(stderr, "Failed to seek to start of file");
>        free(writebuf);
>        close(fd);
>        exit(EXIT_FAILURE);
>    }
>
>    if (!strcmp(argv[2], "half"))
>        rc = writezero(fd, writebuf, st.st_blksize, 4096*1024/2);
>    else if (!strcmp(argv[2], "all"))
>        rc = writezero(fd, writebuf, st.st_blksize, 4096*1024);
>    else {
>        fprintf(stderr, "Invalid arg2='%s', expect half or all", argv[2]);
>        free(writebuf);
>        close(fd);
>        exit(EXIT_FAILURE);
>    }
>    if (rc < 0) {
>        fprintf(stderr, "Failed to write to file");
>        free(writebuf);
>        close(fd);
>        exit(EXIT_FAILURE);
>    }
>
>    free(writebuf);
>    close(fd);
>    return 0;
>}
>
>

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Attachments on bug 1091866: 918532