249 lines
6.7 KiB
C
249 lines
6.7 KiB
C
/*
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rdev.c - query/set root device.
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-------------------------------------------------------------------------
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Date: Sun, 27 Dec 1992 15:55:31 +0000
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Subject: Re: rdev
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From: almesber@nessie.cs.id.ethz.ch (Werner Almesberger)
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To: Rik Faith <faith@cs.unc.edu>
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There are quite a few versions of rdev:
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- the original rootdev that only printed the current root device, by
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Linus.
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- rdev that does what rootdev did and that also allows you to change
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the root (and swap) device, by me.
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- rdev got renamed to setroot and I think even to rootdev on various
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distributions.
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- Peter MacDonald added video mode and RAM disk setting and included
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this version on SLS, called rdev again. I've attached his rdev.c to
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this mail.
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-------------------------------------------------------------------------
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Date: 11 Mar 92 21:37:37 GMT
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Subject: rdev - query/set root device
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From: almesber@nessie.cs.id.ethz.ch (Werner Almesberger)
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Organization: Swiss Federal Institute of Technology (ETH), Zurich, CH
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With all that socket, X11, disk driver and FS hacking going on, apparently
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nobody has found time to address one of the minor nuisances of life: set-
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ting the root FS device is still somewhat cumbersome. I've written a little
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utility which can read and set the root device in boot images:
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rdev accepts an optional offset argument, just in case the address should
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ever move from 508. If called without arguments, rdev outputs an mtab line
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for the current root FS, just like /etc/rootdev does.
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ramsize sets the size of the ramdisk. If size is zero, no ramdisk is used.
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vidmode sets the default video mode at bootup time. -1 uses default video
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mode, -2 uses menu.
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-------------------------------------------------------------------------
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Sun Dec 27 10:42:16 1992: Minor usage changes, faith@cs.unc.edu.
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Tue Mar 30 09:31:52 1993: rdev -Rn to set root readonly flag, sct@dcs.ed.ac.uk
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Wed Jun 22 21:12:29 1994: Applied patches from Dave
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(gentzel@nova.enet.dec.com) to prevent dereferencing
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the NULL pointer, faith@cs.unc.edu
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-------------------------------------------------------------------------
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*/
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#include <stdio.h>
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/* rdev.c - query/set root device. */
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void
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usage()
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{
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puts("usage: rdev [ -rsv ] [ -o OFFSET ] [ IMAGE [ VALUE [ OFFSET ] ] ]");
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puts(" rdev /dev/fd0 (or rdev /linux, etc.) displays the current ROOT device");
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puts(" rdev /dev/fd0 /dev/hda2 sets ROOT to /dev/hda2");
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puts(" rdev -R /dev/fd0 1 set the ROOTFLAGS (readonly status)");
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puts(" rdev -s /dev/fd0 /dev/hda2 set the SWAP device");
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puts(" rdev -r /dev/fd0 627 set the RAMDISK size");
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puts(" rdev -v /dev/fd0 1 set the bootup VIDEOMODE");
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puts(" rdev -o N ... use the byte offset N");
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puts(" rootflags ... same as rdev -R");
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puts(" swapdev ... same as rdev -s");
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puts(" ramsize ... same as rdev -r");
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puts(" vidmode ... same as rdev -v");
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puts("Note: video modes are: -3=Ask, -2=Extended, -1=NormalVga, 1=key1, 2=key2,...");
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puts(" use -R 1 to mount root readonly, -R 0 for read/write.");
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exit(-1);
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}
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#define DEFAULT_OFFSET 508
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static void die(char *msg)
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{
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perror(msg);
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exit(1);
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}
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static char *find_dev(int number)
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{
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DIR *dp;
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struct dirent *dir;
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static char name[PATH_MAX+1];
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struct stat s;
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if (!number) return "Boot device";
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if ((dp = opendir("/dev")) == NULL) die("opendir /dev");
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strcpy(name,"/dev/");
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while ((dir = readdir(dp)) != NULL) {
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strcpy(name+5,dir->d_name);
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if (stat(name,&s) < 0) die(name);
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if ((s.st_mode & S_IFMT) == S_IFBLK && s.st_rdev == number) return name;
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}
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sprintf(name,"0x%04x",number);
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return name;
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}
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/* enum { RDEV, SDEV, RAMSIZE, VIDMODE }; */
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enum { RDEV, VIDMODE, RAMSIZE, SDEV, __syssize__, ROOTFLAGS };
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char *cmdnames[6] = { "rdev", "vidmode", "ramsize", "swapdev",
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"", "rootflags"};
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char *desc[6] = { "Root device", "Video mode", "Ramsize", "Swap device",
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"", "Root flags"};
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#define shift(n) argv+=n,argc-=n
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int main(int argc,char **argv)
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{
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int image,offset,dev_nr, i, newoffset=-1;
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char *device, *ptr;
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struct stat s;
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int cmd = 0;
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device = NULL;
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if ((ptr = strrchr(argv[0],'/')) != NULL)
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ptr++;
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else
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ptr = argv[0];
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for (i=0; i<=5; i++)
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if (!strcmp(ptr,cmdnames[i]))
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break;
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cmd = i;
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if (cmd>5)
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cmd=RDEV;
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offset = DEFAULT_OFFSET-cmd*2;
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while (argc > 1)
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{
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if (argv[1][0] != '-')
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break;
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else
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switch (argv[1][1])
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{
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case 'R':
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cmd=ROOTFLAGS;
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offset = DEFAULT_OFFSET-cmd*2;
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shift(1);
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break;
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case 'r':
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cmd=RAMSIZE;
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offset = DEFAULT_OFFSET-cmd*2;
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shift(1);
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break;
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case 'v':
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cmd=VIDMODE;
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offset = DEFAULT_OFFSET-cmd*2;
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shift(1);
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break;
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case 's':
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cmd=SDEV;
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offset = DEFAULT_OFFSET-cmd*2;
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shift(1);
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break;
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case 'o':
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if (argv[1][2])
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{
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newoffset=atoi(argv[1]+2);
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shift(1);
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break;
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} else if (argc > 2) {
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newoffset=atoi(argv[2]);
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shift(2);
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break;
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}
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/* Fall through. . . */
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default:
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usage();
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}
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}
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if (newoffset >= 0)
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offset = newoffset;
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if ((cmd==RDEV) && (argc == 1 || argc > 4)) {
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if (stat("/",&s) < 0) die("/");
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printf("%s /\n",find_dev(s.st_dev));
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exit(0);
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} else if ((cmd != RDEV) && (argc == 1 || argc > 4)) usage();
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if ((cmd==RDEV) || (cmd==SDEV))
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{
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if (argc == 4) {
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device = argv[2];
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offset = atoi(argv[3]);
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}
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else {
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if (argc == 3) {
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if (isdigit(*argv[2])) offset = atoi(argv[2]);
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else device = argv[2];
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}
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}
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}
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else
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{
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if (argc>=3)
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device = argv[2];
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if (argc==4)
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offset = atoi(argv[3]);
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}
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if (device) {
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if ((cmd==SDEV) || (cmd==RDEV))
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{ if (stat(device,&s) < 0) die(device);
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} else
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s.st_rdev=atoi(device);
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if ((image = open(argv[1],O_WRONLY)) < 0) die(argv[1]);
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if (lseek(image,offset,0) < 0) die("lseek");
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if (write(image,(char *)&s.st_rdev,2) != 2) die(argv[1]);
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if (close(image) < 0) die("close");
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}
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else {
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if ((image = open(argv[1],O_RDONLY)) < 0) die(argv[1]);
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if (lseek(image,offset,0) < 0) die("lseek");
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dev_nr = 0;
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if (read(image,(char *)&dev_nr,2) != 2) die(argv[1]);
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if (close(image) < 0) die("close");
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printf(desc[cmd]);
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if ((cmd==SDEV) || (cmd==RDEV))
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printf(" %s\n", find_dev(dev_nr));
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else
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printf(" %d\n", dev_nr);
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}
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return 0;
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}
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