libblkid: add generic functions for sysfs attributes

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

diff --git a/shlibs/blkid/src/blkidP.h b/shlibs/blkid/src/blkidP.h
index 377cf0e552dd951239968787efbc88e44e093967..7dc39fc30ddb526f07f223dda2b6f7dca22e7414 100644 (file)
--- a/shlibs/blkid/src/blkidP.h
+++ b/shlibs/blkid/src/blkidP.h
@@ -21,6 +21,7 @@
 #include <sys/stat.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include <stdint.h>
 
 #include "c.h"
 #include "bitops.h"    /* $(top_srcdir)/include/ */
@@ -331,6 +332,9 @@ struct dir_list {
 };
 extern void blkid__scan_dir(char *, dev_t, struct dir_list **, char **);
 extern int blkid_driver_has_major(const char *drvname, int major);
+extern int blkid_devno_has_attribute(dev_t devno, const char *attribute);
+extern int blkid_devno_get_attribute(dev_t devno, const char *attribute,
+                                                       uint64_t *result);
 
 /* 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 288e82ee58082e04372e131c29281179f5aa3ad6..1b64ec1e1c00bf0015d2d98bb13843cd220011cd 100644 (file)
--- a/shlibs/blkid/src/devno.c
+++ b/shlibs/blkid/src/devno.c
@@ -30,6 +30,7 @@
 #include <sys/mkdev.h>
 #endif
 #include <fcntl.h>
+#include <inttypes.h>
 
 #include "blkidP.h"
 #include "pathnames.h"
@@ -451,6 +452,50 @@ int blkid_driver_has_major(const char *drvname, int major)
        return match;
 }
 
+static char *mk_devno_attribute_path(char *buf, size_t buflen,
+                               dev_t devno, const char *attr)
+{
+       int len = snprintf(buf, buflen, "/sys/dev/block/%d:%d/%s",
+                       major(devno), minor(devno), attr);
+
+       if (len < 0 || len + 1 > buflen)
+               return NULL;
+
+       return buf;
+}
+
+int blkid_devno_has_attribute(dev_t devno, const char *attribute)
+{
+       char path[PATH_MAX];
+       struct stat info;
+
+       if (!mk_devno_attribute_path(path, sizeof(path), devno, attribute))
+               return 0;
+
+       if (stat(path, &info) == 0)
+               return 1;
+
+       return 0;
+}
+
+int blkid_devno_get_attribute(dev_t devno, const char *attribute, uint64_t *result)
+{
+       FILE *f;
+       char path[PATH_MAX];
+       int rc = 0;
+
+       if (!mk_devno_attribute_path(path, sizeof(path), devno, attribute))
+               return -1;
+
+       f = fopen(path, "r");
+       if (f) {
+               rc = fscanf(f, "%" SCNu64, result);
+               fclose(f);
+       }
+
+       return rc == 1 ? 0 : -1;
+}
+
 #ifdef TEST_PROGRAM
 int main(int argc, char** argv)
 {

diff --git a/shlibs/blkid/src/topology/sysfs.c b/shlibs/blkid/src/topology/sysfs.c
index 20c507f13aeeb56486095aa6dd38129cb5d896a7..ce870f226e6778ce53cfe47d8f65661301343aea 100644 (file)
--- a/shlibs/blkid/src/topology/sysfs.c
+++ b/shlibs/blkid/src/topology/sysfs.c
@@ -11,7 +11,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
-#include <stdint.h>
+#include <inttypes.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ -22,57 +22,30 @@
 static unsigned long dev_topology_attribute(const char *attribute,
                                dev_t dev, dev_t *primary)
 {
-       const char *sysfs_fmt_str = "/sys/dev/block/%d:%d/%s";
-       char path[PATH_MAX];
-       int len;
-       FILE *fp = NULL;
-       struct stat info;
-       unsigned long result = 0UL;
-
-       len = snprintf(path, sizeof(path), sysfs_fmt_str,
-                       major(dev), minor(dev), attribute);
-       if (len < 0 || len + 1 > sizeof(path))
-               goto err;
+       uint64_t result;
 
        /*
         * check if the desired sysfs attribute exists
         * - if not: either the kernel doesn't have topology support or the
         *   device could be a partition
         */
-       if (stat(path, &info) < 0) {
+       if (!blkid_devno_has_attribute(dev, attribute)) {
                if (!*primary &&
                    blkid_devno_to_wholedisk(dev, NULL, 0, primary))
                        goto err;
 
                /* get attribute from partition's primary device */
-               len = snprintf(path, sizeof(path), sysfs_fmt_str,
-                               major(*primary), minor(*primary), attribute);
-               if (len < 0 || len + 1 > sizeof(path))
-                       goto err;
+               dev = *primary;
        }
 
-       fp = fopen(path, "r");
-       if (!fp) {
-               DBG(DEBUG_LOWPROBE, printf(
-                       "topology: %s: fopen failed, errno=%d\n", path, errno));
+       if (blkid_devno_get_attribute(dev, attribute, &result))
                goto err;
-       }
-
-       if (fscanf(fp, "%lu", &result) != 1) {
-               DBG(DEBUG_LOWPROBE, printf(
-                       "topology: %s: unexpected file format\n", path));
-               goto err;
-       }
-
-       fclose(fp);
 
        DBG(DEBUG_LOWPROBE,
-               printf("topology: attribute %s = %lu\n", attribute, result));
+               printf("topology: attribute %s = %" PRIu64 "\n", attribute, result));
 
        return result;
 err:
-       if (fp)
-               fclose(fp);
        DBG(DEBUG_LOWPROBE,
                printf("topology: failed to read %s attribute\n", attribute));
        return 0;