xsh_ls.c

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/* xsh_ls.c - xsh_ls */

#include <xinu.h>
#include <stdio.h>

/*------------------------------------------------------------------------
 * xhs_ls - list the contents of the local file system directory
 *------------------------------------------------------------------------
 */
shellcmd xsh_ls(int nargs, char *args[])
{
    struct  lfdir   *dirptr;    /* Ptr to in-memory directory   */
    int32   i;
    struct  ldentry *ldptr;     /* Ptr to an entry in directory */

    /* For argument '--help', emit help about the 'ls' command  */

    if (nargs == 2 && strncmp(args[1], "--help", 7) == 0) {
        printf("Use: %s\n\n", args[0]);
        printf("Description:\n");
        printf("\tlists the names of files\n");
        printf("Options:\n");
        printf("\t--help\t display this help and exit\n");
        return 0;
    }

    if (nargs != 1) {
        printf("illegal option: try --help for more information\n");
        return 1;
    }

    /* Obtain copy of directory if not already present in memory    */

    dirptr = &Lf_data.lf_dir;
    wait(Lf_data.lf_mutex);
    if (! Lf_data.lf_dirpresent) {
        if (read(Lf_data.lf_dskdev, (char *)dirptr, LF_AREA_DIR) == SYSERR ) {
        signal(Lf_data.lf_mutex);
        fprintf(stderr,"cannot read the directory\n");
        }
        if (lfscheck(dirptr) == SYSERR ) {
        fprintf(stderr, "THe disk does not contain a Xinu file system\n");
        signal(Lf_data.lf_mutex);
        return 1;
        }
        Lf_data.lf_dirpresent = TRUE;
    }
    signal(Lf_data.lf_mutex);

    /* Search directory and list the file names */

    for (i=0; i<dirptr->lfd_nfiles; i++) {
        ldptr = &dirptr->lfd_files[i];
        printf("%s\n", ldptr->ld_name);
    }
    return 0;
}