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 <stdlib.h>
  61 #include "nls.h"
  62
  63 /* rdev.c  -  query/set root device. */
  64
  65 static void
  66 usage(void) {
  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
 100 die(char *msg) {
 101         perror(msg);
 102         exit(1);
 103 }
 104
 105 /* Earlier rdev fails on /dev/ida/c0d0p1 so we allow for
 106    (limited) recursion in /dev. -- Paul Clements */
 107
 108 #define MAX_DEPTH       1
 109
 110 static int
 111 find_dev_recursive(char *dirnamebuf, int number, int depth) {
 112         DIR *dp;
 113         struct dirent *dir;
 114         struct stat s;
 115         int dirnamelen = 0;
 116
 117         if (depth < 0)
 118                 return 0;
 119         if ((dp = opendir(dirnamebuf)) == NULL)
 120                 die("opendir");
 121         dirnamelen = strlen(dirnamebuf);
 122         while ((dir = readdir(dp)) != NULL) {
 123                 if (!strcmp(dir->d_name, ".") || !strcmp(dir->d_name, ".."))
 124                         continue;
 125                 if (dirnamelen + 1 + strlen(dir->d_name) > PATH_MAX)
 126                         continue;
 127                 dirnamebuf[dirnamelen] = '/';
 128                 strcpy(dirnamebuf+dirnamelen+1, dir->d_name);
 129                 if (lstat(dirnamebuf, &s) < 0)
 130                         continue;
 131                 if ((s.st_mode & S_IFMT) == S_IFBLK && s.st_rdev == number)
 132                         return 1;
 133                 if ((s.st_mode & S_IFMT) == S_IFDIR &&
 134                     find_dev_recursive(dirnamebuf, number, depth-1))
 135                         return 1;
 136         }
 137         dirnamebuf[dirnamelen] = 0;
 138         return 0;
 139 }
 140
 141 static char *
 142 find_dev(int number) {
 143         static char name[PATH_MAX+1];
 144
 145         if (!number)
 146                 return "Boot device";
 147         strcpy(name, "/dev");
 148         if (find_dev_recursive(name, number, MAX_DEPTH))
 149                 return name;
 150         sprintf(name, "0x%04x", number);
 151         return name;
 152 }
 153
 154 /* enum { RDEV, SDEV, RAMSIZE, VIDMODE }; */
 155 enum { RDEV, VIDMODE, RAMSIZE, SDEV, __syssize__, ROOTFLAGS };
 156 char *cmdnames[6] = { "rdev", "vidmode",  "ramsize", "swapdev",
 157                       "", "rootflags"};
 158 char *desc[6] = { "Root device", "Video mode",  "Ramsize",  "Swap device",
 159                   "", "Root flags"};
 160 #define shift(n) argv+=n,argc-=n
 161
 162 int
 163 main(int argc, char **argv) {
 164         int image, offset, dev_nr, i, newoffset=-1;
 165         char *device, *ptr;
 166         struct stat s;
 167         int cmd = 0;
 168
 169         setlocale(LC_ALL, "");
 170         bindtextdomain(PACKAGE, LOCALEDIR);
 171         textdomain(PACKAGE);
 172
 173         device = NULL;
 174
 175         /* use the command name to figure out what we have to do - ugly */
 176         cmd = RDEV;
 177         if ((ptr = strrchr(argv[0],'/')) != NULL)
 178                 ptr++;
 179         else
 180                 ptr = argv[0];
 181         for (i=0; i<=5; i++)
 182                 if (!strcmp(ptr,cmdnames[i])) {
 183                         cmd = i;
 184                         break;
 185                 }
 186
 187         while (argc > 1) {
 188                 if (argv[1][0] != '-')
 189                         break;
 190                 switch (argv[1][1]) {
 191                 case 'R':
 192                         cmd = ROOTFLAGS;
 193                         shift(1);
 194                         break;
 195                 case 'r':
 196                         cmd = RAMSIZE;
 197                         shift(1);
 198                         break;
 199                 case 'v':
 200                         cmd = VIDMODE;
 201                         shift(1);
 202                         break;
 203                 case 's':
 204                         cmd = SDEV;
 205                         shift(1);
 206                         break;
 207                 case 'o':
 208                         if (argv[1][2]) {
 209                                 newoffset=atoi(argv[1]+2);
 210                                 shift(1);
 211                                 break;
 212                         } else if (argc > 2) {
 213                                 newoffset=atoi(argv[2]);
 214                                 shift(2);
 215                                 break;
 216                         }
 217                         /* Fall through. . . */
 218                 default:
 219                         usage();
 220                 }
 221         }
 222
 223         offset = DEFAULT_OFFSET-cmd*2;
 224         if (newoffset >= 0)
 225                 offset = newoffset;
 226
 227         if  ((cmd == RDEV) && (argc == 1 || argc > 4)) {
 228                 if (stat("/",&s) < 0) die("/");
 229                 printf("%s /\n", find_dev(s.st_dev));
 230                 exit(0);
 231         } else if ((cmd != RDEV) && (argc == 1 || argc > 4))
 232                 usage();
 233
 234         if ((cmd == RDEV) || (cmd == SDEV)) {
 235                 if (argc == 4) {
 236                         device = argv[2];
 237                         offset = atoi(argv[3]);
 238                 } else {
 239                         if (argc == 3) {
 240                                 if (isdigit(*argv[2]))
 241                                         offset = atoi(argv[2]);
 242                                 else
 243                                         device = argv[2];
 244                         }
 245                 }
 246         } else {
 247                 if (argc>=3)
 248                         device = argv[2];
 249                 if (argc==4)
 250                         offset = atoi(argv[3]);
 251         }
 252         if (device) {
 253                 if ((cmd == SDEV) || (cmd == RDEV)) {
 254                         if (stat(device,&s) < 0)
 255                                 die(device);
 256                 } else
 257                         s.st_rdev=atoi(device);
 258                 if ((image = open(argv[1],O_WRONLY)) < 0) die(argv[1]);
 259                 if (lseek(image,offset,0) < 0) die("lseek");
 260                 if (write(image,(char *)&s.st_rdev,2) != 2) die(argv[1]);
 261                 if (close(image) < 0) die("close");
 262         } else {
 263                 if ((image = open(argv[1],O_RDONLY)) < 0) die(argv[1]);
 264                 if (lseek(image,offset,0) < 0) die("lseek");
 265                 dev_nr = 0;
 266                 if (read(image,(char *)&dev_nr,2) != 2) die(argv[1]);
 267                 if (close(image) < 0) die("close");
 268                 fputs(desc[cmd], stdout);
 269                 if ((cmd == SDEV) || (cmd == RDEV))
 270                         printf(" %s\n", find_dev(dev_nr));
 271                 else
 272                         printf(" %d\n", dev_nr);
 273         }
 274         return 0;
 275 }