sys-utils/rdev.c

   1 /*
   2
   3   rdev.c  -  query/set root device.
   4
   5 -------------------------------------------------------------------------
   6
   7 Date: Sun, 27 Dec 1992 15:55:31 +0000
   8 Subject: Re: rdev
   9 From: almesber@nessie.cs.id.ethz.ch (Werner Almesberger)
  10 To: Rik Faith <faith@cs.unc.edu>
  11
  12 There are quite a few versions of rdev:
  13
  14   - the original rootdev that only printed the current root device, by
  15     Linus.
  16   - rdev that does what rootdev did and that also allows you to change
  17     the root (and swap) device, by me.
  18   - rdev got renamed to setroot and I think even to rootdev on various
  19     distributions.
  20   - Peter MacDonald added video mode and RAM disk setting and included
  21     this version on SLS, called rdev again. I've attached his rdev.c to
  22     this mail.
  23
  24 -------------------------------------------------------------------------
  25
  26 Date: 11 Mar 92 21:37:37 GMT
  27 Subject: rdev - query/set root device
  28 From: almesber@nessie.cs.id.ethz.ch (Werner Almesberger)
  29 Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
  30
  31 With all that socket, X11, disk driver and FS hacking going on, apparently
  32 nobody has found time to address one of the minor nuisances of life: set-
  33 ting the root FS device is still somewhat cumbersome. I've written a little
  34 utility which can read and set the root device in boot images:
  35
  36 rdev accepts an optional offset argument, just in case the address should
  37 ever move from 508. If called without arguments, rdev outputs an mtab line
  38 for the current root FS, just like /etc/rootdev does.
  39
  40 ramsize sets the size of the ramdisk.  If size is zero, no ramdisk is used.
  41
  42 vidmode sets the default video mode at bootup time.  -1 uses default video
  43 mode, -2 uses menu.
  44
  45 -------------------------------------------------------------------------
  46
  47 Sun Dec 27 10:42:16 1992: Minor usage changes, faith@cs.unc.edu.
  48 Tue Mar 30 09:31:52 1993: rdev -Rn to set root readonly flag, sct@dcs.ed.ac.uk
  49 Wed Jun 22 21:12:29 1994: Applied patches from Dave
  50                           (gentzel@nova.enet.dec.com) to prevent dereferencing
  51                           the NULL pointer, faith@cs.unc.edu
  52 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@misiek.eu.org>
  53 - added Native Language Support
  54
  55 -------------------------------------------------------------------------
  56
  57 */
  58
  59 #include <stdio.h>
  60 #include "nls.h"
  61
  62 /* rdev.c  -  query/set root device. */
  63
  64 void
  65 usage()
  66 {
  67
  68     puts(_("usage: rdev [ -rsv ] [ -o OFFSET ] [ IMAGE [ VALUE [ OFFSET ] ] ]"));
  69     puts(_("  rdev /dev/fd0  (or rdev /linux, etc.) displays the current ROOT device"));
  70     puts(_("  rdev /dev/fd0 /dev/hda2         sets ROOT to /dev/hda2"));
  71     puts(_("  rdev -R /dev/fd0 1              set the ROOTFLAGS (readonly status)"));
  72     puts(_("  rdev -s /dev/fd0 /dev/hda2      set the SWAP device"));
  73     puts(_("  rdev -r /dev/fd0 627            set the RAMDISK size"));
  74     puts(_("  rdev -v /dev/fd0 1              set the bootup VIDEOMODE"));
  75     puts(_("  rdev -o N ...                   use the byte offset N"));
  76     puts(_("  rootflags ...                   same as rdev -R"));
  77     puts(_("  swapdev ...                     same as rdev -s"));
  78     puts(_("  ramsize ...                     same as rdev -r"));
  79     puts(_("  vidmode ...                     same as rdev -v"));
  80     puts(_("Note: video modes are: -3=Ask, -2=Extended, -1=NormalVga, 1=key1, 2=key2,..."));
  81     puts(_("      use -R 1 to mount root readonly, -R 0 for read/write."));
  82     exit(-1);
  83 }
  84
  85 #include <stdio.h>
  86 #include <string.h>
  87 #include <ctype.h>
  88 #include <errno.h>
  89 #include <fcntl.h>
  90 #include <dirent.h>
  91 #include <unistd.h>
  92 #include <stdlib.h>
  93 #include <sys/types.h>
  94 #include <sys/stat.h>
  95
  96 #define DEFAULT_OFFSET 508
  97
  98
  99 static void die(char *msg)
 100 {
 101     perror(msg);
 102     exit(1);
 103 }
 104
 105
 106 static char *find_dev(int number)
 107 {
 108     DIR *dp;
 109     struct dirent *dir;
 110     static char name[PATH_MAX+1];
 111     struct stat s;
 112
 113     if (!number) return "Boot device";
 114     if ((dp = opendir("/dev")) == NULL) die("opendir /dev");
 115     strcpy(name,"/dev/");
 116     while ((dir = readdir(dp)) != NULL) {
 117         strcpy(name+5,dir->d_name);
 118         if (stat(name,&s) < 0) die(name);
 119         if ((s.st_mode & S_IFMT) == S_IFBLK && s.st_rdev == number) return name;
 120     }
 121     sprintf(name,"0x%04x",number);
 122     return name;
 123 }
 124
 125 /* enum { RDEV, SDEV, RAMSIZE, VIDMODE }; */
 126 enum { RDEV, VIDMODE, RAMSIZE, SDEV, __syssize__, ROOTFLAGS };
 127 char *cmdnames[6] = { "rdev", "vidmode",  "ramsize", "swapdev",
 128                       "", "rootflags"};
 129 char *desc[6] = { "Root device", "Video mode",  "Ramsize",  "Swap device",
 130                   "", "Root flags"};
 131 #define shift(n) argv+=n,argc-=n
 132
 133 int main(int argc,char **argv)
 134 {
 135     int image,offset,dev_nr, i, newoffset=-1;
 136     char *device, *ptr;
 137     struct stat s;
 138     int cmd = 0;
 139
 140     setlocale(LC_ALL, "");
 141     bindtextdomain(PACKAGE, LOCALEDIR);
 142     textdomain(PACKAGE);
 143
 144     device = NULL;
 145     if ((ptr = strrchr(argv[0],'/')) != NULL)
 146         ptr++;
 147     else
 148         ptr = argv[0];
 149     for (i=0; i<=5; i++)
 150         if (!strcmp(ptr,cmdnames[i]))
 151             break;
 152     cmd = i;
 153     if (cmd>5)
 154         cmd=RDEV;
 155     offset = DEFAULT_OFFSET-cmd*2;
 156
 157     while (argc > 1)
 158     {
 159         if (argv[1][0] != '-')
 160             break;
 161         else
 162             switch (argv[1][1])
 163             {
 164                 case 'R':
 165                         cmd=ROOTFLAGS;
 166                         offset = DEFAULT_OFFSET-cmd*2;
 167                         shift(1);
 168                         break;
 169                 case 'r':
 170                         cmd=RAMSIZE;
 171                         offset = DEFAULT_OFFSET-cmd*2;
 172                         shift(1);
 173                         break;
 174                 case 'v':
 175                         cmd=VIDMODE;
 176                         offset = DEFAULT_OFFSET-cmd*2;
 177                         shift(1);
 178                         break;
 179                 case 's':
 180                         cmd=SDEV;
 181                         offset = DEFAULT_OFFSET-cmd*2;
 182                         shift(1);
 183                         break;
 184                 case 'o':
 185                         if (argv[1][2])
 186                         {
 187                                 newoffset=atoi(argv[1]+2);
 188                                 shift(1);
 189                                 break;
 190                         } else if (argc > 2) {
 191                                 newoffset=atoi(argv[2]);
 192                                 shift(2);
 193                                 break;
 194                         }
 195                         /* Fall through. . . */
 196                 default:
 197                         usage();
 198              }
 199     }
 200     if (newoffset >= 0)
 201         offset = newoffset;
 202
 203     if  ((cmd==RDEV) && (argc == 1 || argc > 4)) {
 204         if (stat("/",&s) < 0) die("/");
 205         printf("%s /\n",find_dev(s.st_dev));
 206         exit(0);
 207     } else if ((cmd != RDEV) && (argc == 1 || argc > 4)) usage();
 208
 209     if ((cmd==RDEV) || (cmd==SDEV))
 210     {
 211             if (argc == 4) {
 212                 device = argv[2];
 213                 offset = atoi(argv[3]);
 214             }
 215             else {
 216                 if (argc == 3) {
 217                     if (isdigit(*argv[2])) offset = atoi(argv[2]);
 218                     else device = argv[2];
 219                 }
 220             }
 221     }
 222     else
 223     {
 224         if (argc>=3)
 225                 device = argv[2];
 226         if (argc==4)
 227                 offset = atoi(argv[3]);
 228     }
 229     if (device) {
 230         if ((cmd==SDEV) || (cmd==RDEV))
 231         {       if (stat(device,&s) < 0) die(device);
 232         } else
 233                 s.st_rdev=atoi(device);
 234         if ((image = open(argv[1],O_WRONLY)) < 0) die(argv[1]);
 235         if (lseek(image,offset,0) < 0) die("lseek");
 236         if (write(image,(char *)&s.st_rdev,2) != 2) die(argv[1]);
 237         if (close(image) < 0) die("close");
 238     }
 239     else {
 240         if ((image = open(argv[1],O_RDONLY)) < 0) die(argv[1]);
 241         if (lseek(image,offset,0) < 0) die("lseek");
 242         dev_nr = 0;
 243         if (read(image,(char *)&dev_nr,2) != 2) die(argv[1]);
 244         if (close(image) < 0) die("close");
 245         printf(desc[cmd]);
 246         if ((cmd==SDEV) || (cmd==RDEV))
 247                 printf(" %s\n", find_dev(dev_nr));
 248         else
 249                 printf(" %d\n", dev_nr);
 250     }
 251     return 0;
 252 }
 253
 254