filesys/t_mount.c

This is filesys/t_mount.c (Listing 14-1, page 268), an example from the book, The Linux Programming Interface.

The source code file is copyright 2024, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

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#include <sys/mount.h>
#include "tlpi_hdr.h"
static void
usageError(const char *progName, const char *msg)
{
    if (msg != NULL)
        fprintf(stderr, "%s", msg);

    fprintf(stderr, "Usage: %s [options] source target\n\n", progName);
    fprintf(stderr, "Available options:\n");
#define fpe(str) fprintf(stderr, "    " str)    /* Shorter! */
    fpe("-t fstype        [e.g., 'ext2' or 'reiserfs']\n");
    fpe("-o data          [file system-dependent options,\n");
    fpe("                 e.g., 'bsdgroups' for ext2]\n");
    fpe("-f mountflags    can include any of:\n");
#define fpe2(str) fprintf(stderr, "            " str)
    fpe2("b - MS_BIND         create a bind mount\n");
    fpe2("d - MS_DIRSYNC      synchronous directory updates\n");
    fpe2("l - MS_MANDLOCK     permit mandatory locking\n");
    fpe2("m - MS_MOVE         atomically move subtree\n");
    fpe2("A - MS_NOATIME      don't update atime (last access time)\n");
    fpe2("V - MS_NODEV        don't permit device access\n");
    fpe2("D - MS_NODIRATIME   don't update atime on directories\n");
    fpe2("E - MS_NOEXEC       don't allow executables\n");
    fpe2("S - MS_NOSUID       disable set-user/group-ID programs\n");
    fpe2("r - MS_RDONLY       read-only mount\n");
    fpe2("c - MS_REC          recursive mount\n");
    fpe2("R - MS_REMOUNT      remount\n");
    fpe2("s - MS_SYNCHRONOUS  make writes synchronous\n");
    exit(EXIT_FAILURE);
}
int
main(int argc, char *argv[])
{
    unsigned long flags;
    char *data, *fstype;
    int j, opt;

    flags = 0;
    data = NULL;
    fstype = NULL;

    while ((opt = getopt(argc, argv, "o:t:f:")) != -1) {
        switch (opt) {
        case 'o':
            data = optarg;
            break;

        case 't':
            fstype = optarg;
            break;

        case 'f':
            for (j = 0; j < strlen(optarg); j++) {
                switch (optarg[j]) {
                case 'b': flags |= MS_BIND;             break;
                case 'd': flags |= MS_DIRSYNC;          break;
                case 'l': flags |= MS_MANDLOCK;         break;
                case 'm': flags |= MS_MOVE;             break;
                case 'A': flags |= MS_NOATIME;          break;
                case 'V': flags |= MS_NODEV;            break;
                case 'D': flags |= MS_NODIRATIME;       break;
                case 'E': flags |= MS_NOEXEC;           break;
                case 'S': flags |= MS_NOSUID;           break;
                case 'r': flags |= MS_RDONLY;           break;
                case 'c': flags |= MS_REC;              break;
                case 'R': flags |= MS_REMOUNT;          break;
                case 's': flags |= MS_SYNCHRONOUS;      break;
                default:  usageError(argv[0], NULL);
                }
            }
            break;

        default:
            usageError(argv[0], NULL);
        }
    }

    if (argc != optind + 2)
        usageError(argv[0], "Wrong number of arguments\n");

    if (mount(argv[optind], argv[optind + 1], fstype, flags, data) == -1)
        errExit("mount");

    exit(EXIT_SUCCESS);
}

 

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