mount.c

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/* mount - mount a file system          Author: Andy Tanenbaum */

#include <errno.h>
#include <sys/types.h>
#include <limits.h>
#include <stdlib.h>
#include <dirent.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/minlib.h>
#include <minix/swap.h>
#include <sys/svrctl.h>
#include <stdio.h>
#include "../../servers/fs/const.h"

_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void list, (void));
_PROTOTYPE(void usage, (void));
_PROTOTYPE(void tell, (char *this));
_PROTOTYPE(void swapon, (char *file));

static u8_t MAGIC[] = { SWAP_MAGIC0, SWAP_MAGIC1, SWAP_MAGIC2, SWAP_MAGIC3 };

int main(argc, argv)
int argc;
char *argv[];
{
  int i, ro, swap, n, v;
  char **ap, *vs, *opt, *err;
  char special[PATH_MAX+1], mounted_on[PATH_MAX+1], version[10], rw_flag[10];

  if (argc == 1) list();        /* just list /etc/mtab */
  ro = 0;
  swap = 0;
  ap = argv+1;
  for (i = 1; i < argc; i++) {
        if (argv[i][0] == '-') {
                opt = argv[i]+1;
                while (*opt != 0) switch (*opt++) {
                case 'r':       ro = 1;         break;
                case 's':       swap = 1;       break;
                default:        usage();
                }
        } else {
                *ap++ = argv[i];
        }
  }
  *ap = NULL;
  argc = (ap - argv);

  if (ro && swap) usage();

  if (swap) {
        if (argc != 2) usage();
        swapon(argv[1]);
        tell(argv[1]);
        tell(" is swapspace\n");
  } else {
        if (argc != 3) usage();
        if (mount(argv[1], argv[2], ro) < 0) {
                err = strerror(errno);
                std_err("mount: Can't mount ");
                std_err(argv[1]);
                std_err(" on ");
                std_err(argv[2]);
                std_err(": ");
                std_err(err);
                std_err("\n");
                exit(1);
        }
        /* The mount has completed successfully. Tell the user. */
        tell(argv[1]);
        tell(" is read-");
        tell(ro ? "only" : "write");
        tell(" mounted on ");
        tell(argv[2]);
        tell("\n");
  }

  /* Update /etc/mtab. */
  n = load_mtab("mount");
  if (n < 0) exit(1);           /* something is wrong. */

  /* Loop on all the /etc/mtab entries, copying each one to the output buf. */
  while (1) {
        n = get_mtab_entry(special, mounted_on, version, rw_flag);
        if (n < 0) break;
        n = put_mtab_entry(special, mounted_on, version, rw_flag);
        if (n < 0) {
                std_err("mount: /etc/mtab has grown too large\n");
                exit(1);
        }
  }
  if (swap) {
        vs = "swap";
  } else {
        v = fsversion(argv[1], "mount");
        if (v == 1)
                vs = "1";
        else if (v == 2)
                vs = "2";
        else if (v == 3)
                vs = "3";
        else
                vs = "0";
  }
  n = put_mtab_entry(argv[1], swap ? "swap" : argv[2], vs, (ro ? "ro" : "rw") );
  if (n < 0) {
        std_err("mount: /etc/mtab has grown too large\n");
        exit(1);
  }

  n = rewrite_mtab("mount");
  return(0);
}


void list()
{
  int n;
  char special[PATH_MAX+1], mounted_on[PATH_MAX+1], version[10], rw_flag[10];

  /* Read and print /etc/mtab. */
  n = load_mtab("mount");
  if (n < 0) exit(1);

  while (1) {
        n = get_mtab_entry(special, mounted_on, version, rw_flag);
        if  (n < 0) break;
        write(1, special, strlen(special));
        if (strcmp(version, "swap") == 0) {
                tell(" is swapspace\n");
        } else {
                tell(" is read-");
                tell(strcmp(rw_flag, "rw") == 0 ? "write" : "only");
                tell(" mounted on ");
                tell(mounted_on);
                tell("\n");
        }
  }
  exit(0);
}


void usage()
{
  std_err("Usage: mount [-r] special name\n       mount -s special\n");
  exit(1);
}


void tell(this)
char *this;
{
  write(1, this, strlen(this));
}

void swapon(file)
char *file;
{
  u32_t super[2][_MAX_BLOCK_SIZE / 2 / sizeof(u32_t)];
  swap_hdr_t *sp;
  struct mmswapon mmswapon;
  int fd, r;
  char *err;
  
  if ((fd = open(file, O_RDWR)) < 0
        || lseek(fd, SUPER_BLOCK_BYTES, SEEK_SET) == -1
        || (r = read(fd, super, _STATIC_BLOCK_SIZE)) < 0
  ) {
        err = strerror(errno);
        std_err("mount: ");
        std_err(file);
        std_err(": ");
        std_err(err);
        std_err("\n");
        exit(1);
  }
  sp = (swap_hdr_t *) &super[0];
  if (memcmp(sp->sh_magic, MAGIC, sizeof(MAGIC)) != 0)
        sp = (swap_hdr_t *) &super[1];
  if (r == _STATIC_BLOCK_SIZE && memcmp(sp->sh_magic, MAGIC, sizeof(MAGIC)) != 0
                        || sp->sh_version > SH_VERSION) {
        std_err("mount: ");
        std_err(file);
        std_err(" is not swapspace\n");
        exit(1);
  }
  close(fd);
  mmswapon.offset = sp->sh_offset;
  mmswapon.size = sp->sh_swapsize;
  strncpy(mmswapon.file, file, sizeof(mmswapon.file));
  mmswapon.file[sizeof(mmswapon.file)-1] = 0;
  if (svrctl(MMSWAPON, &mmswapon) < 0) {
        err = strerror(errno);
        std_err("mount: ");
        std_err(file);
        std_err(": ");
        std_err(err);
        std_err("\n");
        exit(1);
  }
}

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