setflags.c

/* setflags.c - set the ext2 attributes for a set of files */

/* The first parameter to this program is a string consisting of
   0 (an empty string is okay) or more of the letters I, A, S, and
   N. This string specifies which ext2 attributes should be turned
   on for the files which are specified on the rest of the command
   line -- the rest of the attributes are turned off. The letters
   stand for immutable, append-only, sync, and nodump, respectively.

   For example, the command "setflags IN file1 file2" turns on the
   immutable and nodump flags for files file1 and file2, but turns
   off the sync and append-only flags for those files. */

#include <errno.h>
#include <fcntl.h>
#include <linux/ext2_fs.h>
#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>
#include <unistd.h>

int main(int argc, char ** argv) {
    char ** filename = argv + 1;
    int fd;
    int flags = 0;
    
    /* make sure the flags to set were specified, along with
       some file names */
    if (argc < 3) {
        fprintf(stderr, "setflags usage: [I][A][S][N] <filenames>\n");
        return 1;
    }

    /* each letter represents a flag; set the flags which are 
       specified */
    if (strchr(argv[1], 'I')) flags |= EXT2_IMMUTABLE_FL;
    if (strchr(argv[1], 'A')) flags |= EXT2_APPEND_FL;
    if (strchr(argv[1], 'S')) flags |= EXT2_SYNC_FL;
    if (strchr(argv[1], 'N')) flags |= EXT2_NODUMP_FL;
    
    /* iterate over all of the file names in argv[] */
    while (*(++filename)) {
	/* Unlike normal attributes, ext2 attributes can only
	   be set if we have a file descriptor (a file name
	   isn't sufficient). We don't need write access to set
	   the ext2 attributes, so O_RDONLY is fine. */
        fd = open(*filename, O_RDONLY);
        if (fd < 0) {
            fprintf(stderr, "cannot open %s: %s\n", *filename,
                    strerror(errno));
            return 1;
        }

	/* Sets the attributes as specified by the contents of
	   flags. */
        if (ioctl(fd, EXT2_IOC_SETFLAGS, &flags)) {
            fprintf(stderr, "ioctl failed on %s: %s\n", *filename,
                    strerror(errno));
            return 1;
        }
        close(fd);
    } 

    return 0;
};