| 1 | /* printroot - print root device on stdout Author: Bruce Evans */
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| 2 |
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| 3 | /* This program figures out what the root device is by doing a stat on it, and
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| 4 | * then searching /dev until it finds an entry with the same device number.
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| 5 | * A typical use (probably the only use) is in /etc/rc for initializing
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| 6 | * /etc/mtab, as follows:
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| 7 | *
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| 8 | * /usr/bin/printroot >/etc/mtab
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| 9 | *
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| 10 | * 9 Dec 1989 - clean up for 1.5 - full prototypes (BDE)
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| 11 | * 15 Oct 1989 - avoid ACK cc bugs (BDE):
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| 12 | * - sizeof "foo" is 2 (from wrong type char *) instead of 4
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| 13 | * - char foo[10] = "bar"; allocates 4 bytes instead of 10
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| 14 | * 1 Oct 1989 - Minor changes by Andy Tanenbaum
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| 15 | * 5 Oct 1992 - Use readdir (kjb)
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| 16 | * 26 Nov 1994 - Flag -r: print just the root device (kjb)
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| 17 | */
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| 18 |
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| 19 | #include <sys/types.h>
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| 20 | #include <sys/stat.h>
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| 21 | #include <fcntl.h>
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| 22 | #include <limits.h>
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| 23 | #include <stdlib.h>
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| 24 | #include <string.h>
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| 25 | #include <unistd.h>
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| 26 | #include <minix/minlib.h>
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| 27 | #include <dirent.h>
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| 28 |
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| 29 | static char DEV_PATH[] = "/dev/"; /* #define would step on sizeof bug */
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| 30 | static char MESSAGE[] = " / "; /* ditto */
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| 31 | #define UNKNOWN_DEV "/dev/unknown"
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| 32 | #define ROOT "/"
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| 33 | int rflag;
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| 34 |
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| 35 | _PROTOTYPE(int main, (int argc, char **argv));
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| 36 | _PROTOTYPE(void done, (char *name, int status));
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| 37 |
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| 38 | int main(argc, argv)
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| 39 | int argc;
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| 40 | char **argv;
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| 41 | {
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| 42 | DIR *dp;
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| 43 | struct dirent *entry;
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| 44 | struct stat filestat, rootstat;
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| 45 | static char namebuf[sizeof DEV_PATH + NAME_MAX];
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| 46 |
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| 47 | rflag = (argc > 1 && strcmp(argv[1], "-r") == 0);
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| 48 |
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| 49 | if (stat(ROOT, &rootstat) == 0 && (dp = opendir(DEV_PATH)) != (DIR *) NULL) {
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| 50 | while ((entry = readdir(dp)) != (struct dirent *) NULL) {
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| 51 | strcpy(namebuf, DEV_PATH);
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| 52 | strcat(namebuf, entry->d_name);
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| 53 | if (stat(namebuf, &filestat) != 0) continue;
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| 54 | if ((filestat.st_mode & S_IFMT) != S_IFBLK) continue;
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| 55 | if (filestat.st_rdev != rootstat.st_dev) continue;
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| 56 | done(namebuf, 0);
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| 57 | }
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| 58 | }
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| 59 | done(UNKNOWN_DEV, 1);
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| 60 | return(0); /* not reached */
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| 61 | }
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| 62 |
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| 63 | void done(name, status)
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| 64 | char *name;
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| 65 | int status;
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| 66 | {
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| 67 | int v;
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| 68 |
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| 69 | write(1, name, strlen(name));
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| 70 | if (rflag) {
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| 71 | write(1, "\n", 1);
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| 72 | exit(status);
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| 73 | }
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| 74 | write(1, MESSAGE, sizeof MESSAGE - 1);
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| 75 | v = fsversion(name, "printroot"); /* determine file system version */
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| 76 | if (v == 1)
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| 77 | write(1, "1 rw\n", 5);
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| 78 | else if (v == 2)
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| 79 | write(1, "2 rw\n", 5);
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| 80 | else if (v == 3)
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| 81 | write(1, "3 rw\n", 5);
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| 82 | else
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| 83 | write(1, "0 rw\n", 5);
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| 84 | exit(status);
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| 85 | }
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