84 lines
2.4 KiB
C
84 lines
2.4 KiB
C
/* printroot - print root device on stdout Author: Bruce Evans */
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/* This program figures out what the root device is by doing a stat on it, and
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* then searching /dev until it finds an entry with the same device number.
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* A typical use (probably the only use) is in /etc/rc for initializing
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* /etc/mtab, as follows:
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*
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* /usr/bin/printroot >/etc/mtab
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*
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* 9 Dec 1989 - clean up for 1.5 - full prototypes (BDE)
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* 15 Oct 1989 - avoid ACK cc bugs (BDE):
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* - sizeof "foo" is 2 (from wrong type char *) instead of 4
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* - char foo[10] = "bar"; allocates 4 bytes instead of 10
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* 1 Oct 1989 - Minor changes by Andy Tanenbaum
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* 5 Oct 1992 - Use readdir (kjb)
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* 26 Nov 1994 - Flag -r: print just the root device (kjb)
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <minix/minlib.h>
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#include <dirent.h>
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static char DEV_PATH[] = "/dev/"; /* #define would step on sizeof bug */
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static char MESSAGE[] = " / "; /* ditto */
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#define UNKNOWN_DEV "/dev/unknown"
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#define ROOT "/"
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int rflag;
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_PROTOTYPE(int main, (int argc, char **argv));
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_PROTOTYPE(void done, (char *name, int status));
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int main(argc, argv)
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int argc;
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char **argv;
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{
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DIR *dp;
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struct dirent *entry;
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struct stat filestat, rootstat;
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static char namebuf[sizeof DEV_PATH + NAME_MAX];
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rflag = (argc > 1 && strcmp(argv[1], "-r") == 0);
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if (stat(ROOT, &rootstat) == 0 && (dp = opendir(DEV_PATH)) != (DIR *) NULL) {
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while ((entry = readdir(dp)) != (struct dirent *) NULL) {
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strcpy(namebuf, DEV_PATH);
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strcat(namebuf, entry->d_name);
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if (stat(namebuf, &filestat) != 0) continue;
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if ((filestat.st_mode & S_IFMT) != S_IFBLK) continue;
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if (filestat.st_rdev != rootstat.st_dev) continue;
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done(namebuf, 0);
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}
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}
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done(UNKNOWN_DEV, 1);
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return(0); /* not reached */
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}
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void done(name, status)
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char *name;
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int status;
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{
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int v;
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write(1, name, strlen(name));
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if (rflag) {
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write(1, "\n", 1);
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exit(status);
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}
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write(1, MESSAGE, sizeof MESSAGE - 1);
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v = fsversion(name, "printroot"); /* determine file system version */
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switch (v) {
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case FSVERSION_MFS1: write(1, "1 rw\n", 5); break;
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case FSVERSION_MFS2: write(1, "2 rw\n", 5); break;
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case FSVERSION_MFS3: write(1, "3 rw\n", 5); break;
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case FSVERSION_EXT2: write(1, "ext2 rw\n", 8); break;
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default: write(1, "0 rw\n", 5); break;
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}
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exit(status);
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}
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