1 files changed, 379 insertions, 0 deletions

diff --git a/libblkid/devno.c b/libblkid/devno.c
new file mode 100644
index 000000000..906c91fcd
--- /dev/null
+++ b/libblkid/devno.c
@@ -0,0 +1,379 @@
+/*
+ * devno.c - find a particular device by its device number (major/minor)
+ *
+ * Copyright (C) 2000, 2001, 2003 Theodore Ts'o
+ * Copyright (C) 2001 Andreas Dilger
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <stdlib.h>
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#include <dirent.h>
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#ifdef HAVE_SYS_MKDEV_H
+#include <sys/mkdev.h>
+#endif
+#include <fcntl.h>
+#include <inttypes.h>
+
+#include "blkidP.h"
+#include "pathnames.h"
+#include "at.h"
+#include "sysfs.h"
+
+static char *blkid_strconcat(const char *a, const char *b, const char *c)
+{
+	char *res, *p;
+	size_t len, al, bl, cl;
+
+	al = a ? strlen(a) : 0;
+	bl = b ? strlen(b) : 0;
+	cl = c ? strlen(c) : 0;
+
+	len = al + bl + cl;
+	if (!len)
+		return NULL;
+	p = res = malloc(len + 1);
+	if (!res)
+		return NULL;
+	if (al) {
+		memcpy(p, a, al);
+		p += al;
+	}
+	if (bl) {
+		memcpy(p, b, bl);
+		p += bl;
+	}
+	if (cl) {
+		memcpy(p, c, cl);
+		p += cl;
+	}
+	*p = '\0';
+	return res;
+}
+
+/*
+ * This function adds an entry to the directory list
+ */
+static void add_to_dirlist(const char *dir, const char *subdir,
+				struct dir_list **list)
+{
+	struct dir_list *dp;
+
+	dp = malloc(sizeof(struct dir_list));
+	if (!dp)
+		return;
+	dp->name = subdir ? blkid_strconcat(dir, "/", subdir) :
+		   dir ? strdup(dir) : NULL;
+
+	if (!dp->name) {
+		free(dp);
+		return;
+	}
+	dp->next = *list;
+	*list = dp;
+}
+
+/*
+ * This function frees a directory list
+ */
+static void free_dirlist(struct dir_list **list)
+{
+	struct dir_list *dp, *next;
+
+	for (dp = *list; dp; dp = next) {
+		next = dp->next;
+		free(dp->name);
+		free(dp);
+	}
+	*list = NULL;
+}
+
+void blkid__scan_dir(char *dirname, dev_t devno, struct dir_list **list,
+		     char **devname)
+{
+	DIR	*dir;
+	struct dirent *dp;
+	struct stat st;
+
+	if ((dir = opendir(dirname)) == NULL)
+		return;
+
+	while ((dp = readdir(dir)) != NULL) {
+#ifdef _DIRENT_HAVE_D_TYPE
+		if (dp->d_type != DT_UNKNOWN && dp->d_type != DT_BLK &&
+		    dp->d_type != DT_LNK && dp->d_type != DT_DIR)
+			continue;
+#endif
+		if (dp->d_name[0] == '.' &&
+		    ((dp->d_name[1] == 0) ||
+		     ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
+			continue;
+
+		if (fstat_at(dirfd(dir), dirname, dp->d_name, &st, 0))
+			continue;
+
+		if (S_ISBLK(st.st_mode) && st.st_rdev == devno) {
+			*devname = blkid_strconcat(dirname, "/", dp->d_name);
+			DBG(DEBUG_DEVNO,
+			    printf("found 0x%llx at %s\n", (long long)devno,
+				   *devname));
+			break;
+		}
+
+		if (!list || !S_ISDIR(st.st_mode))
+			continue;
+
+		/* add subdirectory (but not symlink) to the list */
+#ifdef _DIRENT_HAVE_D_TYPE
+		if (dp->d_type == DT_LNK)
+			continue;
+		if (dp->d_type == DT_UNKNOWN)
+#endif
+		{
+			if (fstat_at(dirfd(dir), dirname, dp->d_name, &st, 1) ||
+			    !S_ISDIR(st.st_mode))
+				continue;	/* symlink or lstat() failed */
+		}
+
+		if (*dp->d_name == '.' || (
+#ifdef _DIRENT_HAVE_D_TYPE
+		    dp->d_type == DT_DIR &&
+#endif
+		    strcmp(dp->d_name, "shm") == 0))
+			/* ignore /dev/.{udev,mount,mdadm} and /dev/shm */
+			continue;
+
+		add_to_dirlist(dirname, dp->d_name, list);
+	}
+	closedir(dir);
+	return;
+}
+
+/* Directories where we will try to search for device numbers */
+static const char *devdirs[] = { "/devices", "/devfs", "/dev", NULL };
+
+/**
+ * SECTION: misc
+ * @title: Miscellaneous utils
+ * @short_description: mix of various utils for low-level and high-level API
+ */
+
+
+
+static char *scandev_devno_to_devpath(dev_t devno)
+{
+	struct dir_list *list = NULL, *new_list = NULL;
+	char *devname = NULL;
+	const char **dir;
+
+	/*
+	 * Add the starting directories to search in reverse order of
+	 * importance, since we are using a stack...
+	 */
+	for (dir = devdirs; *dir; dir++)
+		add_to_dirlist(*dir, NULL, &list);
+
+	while (list) {
+		struct dir_list *current = list;
+
+		list = list->next;
+		DBG(DEBUG_DEVNO, printf("directory %s\n", current->name));
+		blkid__scan_dir(current->name, devno, &new_list, &devname);
+		free(current->name);
+		free(current);
+		if (devname)
+			break;
+		/*
+		 * If we're done checking at this level, descend to
+		 * the next level of subdirectories. (breadth-first)
+		 */
+		if (list == NULL) {
+			list = new_list;
+			new_list = NULL;
+		}
+	}
+	free_dirlist(&list);
+	free_dirlist(&new_list);
+
+	return devname;
+}
+
+/**
+ * blkid_devno_to_devname:
+ * @devno: device number
+ *
+ * This function finds the pathname to a block device with a given
+ * device number.
+ *
+ * Returns: a pointer to allocated memory to the pathname on success,
+ * and NULL on failure.
+ */
+char *blkid_devno_to_devname(dev_t devno)
+{
+	char *path = NULL;
+	char buf[PATH_MAX];
+
+	path = sysfs_devno_to_devpath(devno, buf, sizeof(buf));
+	if (path)
+		path = strdup(path);
+	if (!path)
+		path = scandev_devno_to_devpath(devno);
+
+	if (!path) {
+		DBG(DEBUG_DEVNO,
+		    printf("blkid: couldn't find devno 0x%04lx\n",
+			   (unsigned long) devno));
+	} else {
+		DBG(DEBUG_DEVNO,
+		    printf("found devno 0x%04llx as %s\n", (long long)devno, path));
+	}
+
+	return path;
+}
+
+
+/**
+ * blkid_devno_to_wholedisk:
+ * @dev: device number
+ * @diskname: buffer to return diskname (or NULL)
+ * @len: diskname buffer size (or 0)
+ * @diskdevno: pointer to returns devno of entire disk (or NULL)
+ *
+ * This function uses sysfs to convert the @devno device number to the *name*
+ * of the whole disk. The function DOES NOT return full device name. The @dev
+ * argument could be partition or whole disk -- both is converted.
+ *
+ * For example: sda1, 0x0801 --> sda, 0x0800
+ *
+ * For conversion to the full disk *path* use blkid_devno_to_devname(), for
+ * example:
+ *
+ * <informalexample>
+ *  <programlisting>
+ *
+ *	dev_t dev = 0x0801, disk;		// sda1 = 8:1
+ *	char *diskpath, diskname[32];
+ *
+ *	blkid_devno_to_wholedisk(dev, diskname, sizeof(diskname), &disk);
+ *	diskpath = blkid_devno_to_devname(disk);
+ *
+ *	// print "0x0801: sda, /dev/sda, 8:0
+ *	printf("0x%x: %s, %s, %d:%d\n",
+ *		dev, diskname, diskpath, major(disk), minor(disk));
+ *
+ *	free(diskpath);
+ *
+ *  </programlisting>
+ * </informalexample>
+ *
+ * Returns: 0 on success or -1 in case of error.
+ */
+int blkid_devno_to_wholedisk(dev_t dev, char *diskname,
+			size_t len, dev_t *diskdevno)
+{
+	return sysfs_devno_to_wholedisk( dev, diskname, len, diskdevno);
+}
+
+/*
+ * Returns 1 if the @major number is associated with @drvname.
+ */
+int blkid_driver_has_major(const char *drvname, int major)
+{
+	FILE *f;
+	char buf[128];
+	int match = 0;
+
+	f = fopen(_PATH_PROC_DEVICES, "r");
+	if (!f)
+		return 0;
+
+	while (fgets(buf, sizeof(buf), f)) {	/* skip to block dev section */
+		if (strncmp("Block devices:\n", buf, sizeof(buf)) == 0)
+			break;
+	}
+
+	while (fgets(buf, sizeof(buf), f)) {
+		int maj;
+		char name[64 + 1];
+
+		if (sscanf(buf, "%d %64[^\n ]", &maj, name) != 2)
+			continue;
+
+		if (maj == major && strcmp(name, drvname) == 0) {
+			match = 1;
+			break;
+		}
+	}
+
+	fclose(f);
+
+	DBG(DEBUG_DEVNO, printf("major %d %s associated with '%s' driver\n",
+			major, match ? "is" : "is NOT", drvname));
+	return match;
+}
+
+
+#ifdef TEST_PROGRAM
+int main(int argc, char** argv)
+{
+	char	*devname, *tmp;
+	char	diskname[PATH_MAX];
+	int	major, minor;
+	dev_t	devno, disk_devno;
+	const char *errmsg = "Couldn't parse %s: %s\n";
+
+	blkid_init_debug(DEBUG_ALL);
+	if ((argc != 2) && (argc != 3)) {
+		fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n"
+			"Resolve a device number to a device name\n",
+			argv[0], argv[0]);
+		exit(1);
+	}
+	if (argc == 2) {
+		devno = strtoul(argv[1], &tmp, 0);
+		if (*tmp) {
+			fprintf(stderr, errmsg, "device number", argv[1]);
+			exit(1);
+		}
+	} else {
+		major = strtoul(argv[1], &tmp, 0);
+		if (*tmp) {
+			fprintf(stderr, errmsg, "major number", argv[1]);
+			exit(1);
+		}
+		minor = strtoul(argv[2], &tmp, 0);
+		if (*tmp) {
+			fprintf(stderr, errmsg, "minor number", argv[2]);
+			exit(1);
+		}
+		devno = makedev(major, minor);
+	}
+	printf("Looking for device 0x%04llx\n", (long long)devno);
+	devname = blkid_devno_to_devname(devno);
+	free(devname);
+
+	printf("Looking for whole-device for 0x%04llx\n", (long long)devno);
+	if (blkid_devno_to_wholedisk(devno, diskname,
+				sizeof(diskname), &disk_devno) == 0)
+		printf("found devno 0x%04llx as /dev/%s\n", (long long) disk_devno, diskname);
+
+	return 0;
+}
+#endif