From: Karel Zak <kzak@redhat.com>
Date: Fri, 18 Sep 2009 11:07:05 +0000 (+0200)
Subject: libblkid: add blkid_driver_has_major()
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ef93b3eff22c6671c12621fef26853c907435ec;p=util-linux

libblkid: add blkid_driver_has_major()

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/include/pathnames.h b/include/pathnames.h
index f958a13b..efe5c3bc 100644
--- a/include/pathnames.h
+++ b/include/pathnames.h
@@ -74,6 +74,7 @@
 #define _PATH_PROC_FILESYSTEMS	"/proc/filesystems"
 #define _PATH_PROC_MOUNTS	"/proc/mounts"
 #define _PATH_PROC_PARTITIONS	"/proc/partitions"
+#define _PATH_PROC_DEVICES	"/proc/devices"
 
 #ifndef _PATH_MOUNTED
 # ifdef MOUNTED					/* deprecated */
diff --git a/shlibs/blkid/src/blkidP.h b/shlibs/blkid/src/blkidP.h
index 64ebeee8..10c29776 100644
--- a/shlibs/blkid/src/blkidP.h
+++ b/shlibs/blkid/src/blkidP.h
@@ -339,6 +339,7 @@ struct dir_list {
 	struct dir_list *next;
 };
 extern void blkid__scan_dir(char *, dev_t, struct dir_list **, char **);
+extern int blkid_driver_has_major(const char *drvname, int major);
 
 /* lseek.c */
 extern blkid_loff_t blkid_llseek(int fd, blkid_loff_t offset, int whence);
diff --git a/shlibs/blkid/src/devno.c b/shlibs/blkid/src/devno.c
index c976228a..8518f9fd 100644
--- a/shlibs/blkid/src/devno.c
+++ b/shlibs/blkid/src/devno.c
@@ -32,6 +32,7 @@
 #endif
 
 #include "blkidP.h"
+#include "pathnames.h"
 
 char *blkid_strndup(const char *s, int length)
 {
@@ -328,6 +329,43 @@ err:
 	return -1;
 }
 
+/*
+ * 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)) {
+		unsigned int maj;
+		char name[64];
+
+		if (sscanf(buf, "%u %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)