1 files changed, 242 insertions, 0 deletions
diff --git a/lib/blkid/devno.c b/lib/blkid/devno.c
new file mode 100644
index 0000000..b1cadc9
--- /dev/null
+++ b/lib/blkid/devno.c
@@ -0,0 +1,242 @@
+/*
+ * 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 "config.h"
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#include <dirent.h>
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#if HAVE_SYS_MKDEV_H
+#include <sys/mkdev.h>
+#endif
+#ifdef HAVE_SYS_SYSMACROS_H
+#include <sys/sysmacros.h>
+#endif
+
+#include "blkidP.h"
+
+#if defined(__GNUC__) && __GNUC__ >= 8
+/* gcc incorrectly thinks the destination string is not being null-terminated */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-truncation"
+#endif
+
+char *blkid_strndup(const char *s, int length)
+{
+	char *ret;
+
+	if (!s)
+		return NULL;
+
+	if (!length)
+		length = strlen(s);
+
+	ret = malloc(length + 1);
+	if (ret) {
+		strncpy(ret, s, length);
+		ret[length] = '\0';
+	}
+	return ret;
+}
+
+#if defined(__GNUC__) && __GNUC__ >= 8
+#pragma GCC diagnostic pop
+#endif
+
+char *blkid_strdup(const char *s)
+{
+	return blkid_strndup(s, 0);
+}
+
+/*
+ * This function adds an entry to the directory list
+ */
+static void add_to_dirlist(const char *name, struct dir_list **list)
+{
+	struct dir_list *dp;
+
+	dp = malloc(sizeof(struct dir_list));
+	if (!dp)
+		return;
+	dp->name = blkid_strdup(name);
+	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(const char *dirname, dev_t devno, struct dir_list **list,
+		     char **devname)
+{
+	DIR	*dir;
+	struct dirent *dp;
+	char	path[1024];
+	int	dirlen;
+	struct stat st;
+
+	if ((dir = opendir(dirname)) == NULL)
+		return;
+	dirlen = strlen(dirname) + 2;
+	while ((dp = readdir(dir)) != 0) {
+		if (dirlen + strlen(dp->d_name) >= sizeof(path))
+			continue;
+
+		if (dp->d_name[0] == '.' &&
+		    ((dp->d_name[1] == 0) ||
+		     ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
+			continue;
+
+		sprintf(path, "%s/%s", dirname, dp->d_name);
+		if (stat(path, &st) < 0)
+			continue;
+
+		if (blkidP_is_disk_device(st.st_mode) && st.st_rdev == devno) {
+			*devname = blkid_strdup(path);
+			DBG(DEBUG_DEVNO,
+			    printf("found 0x%llx at %s (%p)\n", (long long)devno,
+				   path, *devname));
+			break;
+		}
+		if (list && S_ISDIR(st.st_mode) && !lstat(path, &st) &&
+		    S_ISDIR(st.st_mode))
+			add_to_dirlist(path, list);
+	}
+	closedir(dir);
+	return;
+}
+
+/* Directories where we will try to search for device numbers */
+static const char *devdirs[] = { "/devices", "/devfs", "/dev", NULL };
+
+/*
+ * This function finds the pathname to a block device with a given
+ * device number.  It returns a pointer to allocated memory to the
+ * pathname on success, and NULL on failure.
+ */
+char *blkid_devno_to_devname(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, &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);
+
+	if (!devname) {
+		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, devname));
+	}
+
+
+	return devname;
+}
+
+#ifdef TEST_PROGRAM
+int main(int argc, char** argv)
+{
+	char	*devname, *tmp;
+	int	major, minor;
+	dev_t	devno;
+	const char *errmsg = "Couldn't parse %s: %s\n";
+
+	blkid_debug_mask = 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);
+	return 0;
+}
+#endif