import base_device.c for fsck

e2fsprogs/base_device.c

@@ -0,0 +1,147 @@
+/*
+ * base_device.c
+ *
+ * Return the "base device" given a particular device; this is used to
+ * assure that we only fsck one partition on a particular drive at any
+ * one time.  Otherwise, the disk heads will be seeking all over the
+ * place.  If the base device can not be determined, return NULL.
+ * 
+ * The base_device() function returns an allocated string which must
+ * be freed.
+ * 
+ * Written by Theodore Ts'o, <tytso@mit.edu>
+ * 
+ * Copyright (C) 2000 Theodore Ts'o.
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+
+#include "busybox.h"
+
+#ifdef CONFIG_FEATURE_DEVFS
+/*
+ * Required for the uber-silly devfs /dev/ide/host1/bus2/target3/lun3
+ * pathames.
+ */
+static const char *devfs_hier[] = {
+	"host", "bus", "target", "lun", 0
+};
+#endif
+
+char *base_device(const char *device)
+{
+	char *str, *cp;
+#ifdef CONFIG_FEATURE_DEVFS
+	const char **hier, *disk;
+	int len;
+#endif
+
+	cp = str = bb_xstrdup(device);
+
+	/* Skip over /dev/; if it's not present, give up. */
+	if (strncmp(cp, "/dev/", 5) != 0)
+		goto errout;
+	cp += 5;
+
+#if 0	/* this is for old stuff no one uses anymore ? */
+	/* Skip over /dev/dsk/... */
+	if (strncmp(cp, "dsk/", 4) == 0)
+		cp += 4;
+#endif
+
+	/*
+	 * For md devices, we treat them all as if they were all
+	 * on one disk, since we don't know how to parallelize them.
+	 */
+	if (cp[0] == 'm' && cp[1] == 'd') {
+		*(cp+2) = 0;
+		return str;
+	}
+
+	/* Handle DAC 960 devices */
+	if (strncmp(cp, "rd/", 3) == 0) {
+		cp += 3;
+		if (cp[0] != 'c' || cp[2] != 'd' ||
+		    !isdigit(cp[1]) || !isdigit(cp[3]))
+			goto errout;
+		*(cp+4) = 0;
+		return str;
+	}
+
+	/* Now let's handle /dev/hd* and /dev/sd* devices.... */
+	if ((cp[0] == 'h' || cp[0] == 's') && (cp[1] == 'd')) {
+		cp += 2;
+		/* If there's a single number after /dev/hd, skip it */
+		if (isdigit(*cp))
+			cp++;
+		/* What follows must be an alpha char, or give up */
+		if (!isalpha(*cp))
+			goto errout;
+		*(cp + 1) = 0;
+		return str;
+	}
+
+#ifdef CONFIG_FEATURE_DEVFS
+	/* Now let's handle devfs (ugh) names */
+	len = 0;
+	if (strncmp(cp, "ide/", 4) == 0)
+		len = 4;
+	if (strncmp(cp, "scsi/", 5) == 0)
+		len = 5;
+	if (len) {
+		cp += len;
+		/*
+		 * Now we proceed down the expected devfs hierarchy.
+		 * i.e., .../host1/bus2/target3/lun4/...
+		 * If we don't find the expected token, followed by
+		 * some number of digits at each level, abort.
+		 */
+		for (hier = devfs_hier; *hier; hier++) {
+			len = strlen(*hier);
+			if (strncmp(cp, *hier, len) != 0)
+				goto errout;
+			cp += len;
+			while (*cp != '/' && *cp != 0) {
+				if (!isdigit(*cp))
+					goto errout;
+				cp++;
+			}
+			cp++;
+		}
+		*(cp - 1) = 0;
+		return str;
+	}
+
+	/* Now handle devfs /dev/disc or /dev/disk names */
+	disk = 0;
+	if (strncmp(cp, "discs/", 6) == 0)
+		disk = "disc";
+	else if (strncmp(cp, "disks/", 6) == 0)
+		disk = "disk";
+	if (disk) {
+		cp += 6;
+		if (strncmp(cp, disk, 4) != 0)
+			goto errout;
+		cp += 4;
+		while (*cp != '/' && *cp != 0) {
+			if (!isdigit(*cp))
+				goto errout;
+			cp++;
+		}
+		*cp = 0;
+		return str;
+	}
+#endif
+
+errout:
+	free(str);
+	return NULL;
+}