fdisk: backport disk check from util-linux

With the digit check devices like mmcblk0 were skipped,
but now with 0 allowed we're seeing a ton of loop devices listed
(loop0, loop10, loop20...) as well as ramzswap0,
all which should not be shown in fdisk -l.

function                                             old     new   delta
list_devs_in_proc_partititons                        157     238     +81

Signed-off-by: Lauri Kasanen <curaga@operamail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 28 insertions, 7 deletions

diff --git a/util-linux/fdisk.c b/util-linux/fdisk.c
index da03e683e..f4fd4d31d 100644
--- a/util-linux/fdisk.c
+++ b/util-linux/fdisk.c
@@ -2846,13 +2846,37 @@ open_list_and_close(const char *device, int user_specified)
         close_dev_fd();
 }
 
+/* Is it a whole disk? The digit check is still useful
+   for Xen devices for example. */
+static int is_whole_disk(const char *disk)
+{
+        unsigned len;
+        int fd = open(disk, O_RDONLY);
+
+        if (fd != -1) {
+                struct hd_geometry geometry;
+                int err = ioctl(fd, HDIO_GETGEO, &geometry);
+                close(fd);
+                if (!err)
+                        return (geometry.start == 0);
+        }
+
+        /* Treat "nameN" as a partition name, not whole disk */
+        /* note: mmcblk0 should work from the geometry check above */
+        len = strlen(disk);
+        if (len != 0 && isdigit(disk[len - 1]))
+                return 0;
+
+        return 1;
+}
+
 /* for fdisk -l: try all things in /proc/partitions
    that look like a partition name (do not end in a digit) */
 static void
 list_devs_in_proc_partititons(void)
 {
         FILE *procpt;
-        char line[100], ptname[100], devname[120], *s;
+        char line[100], ptname[100], devname[120];
         int ma, mi, sz;
 
         procpt = fopen_or_warn("/proc/partitions", "r");
@@ -2861,13 +2885,10 @@ list_devs_in_proc_partititons(void)
                 if (sscanf(line, " %u %u %u %[^\n ]",
                                 &ma, &mi, &sz, ptname) != 4)
                         continue;
-                for (s = ptname; *s; s++)
-                        continue;
-                /* note: excluding '0': e.g. mmcblk0 is not a partition name! */
-                if (s[-1] >= '1' && s[-1] <= '9')
-                        continue;
+
                 sprintf(devname, "/dev/%s", ptname);
-                open_list_and_close(devname, 0);
+                if (is_whole_disk(devname))
+                        open_list_and_close(devname, 0);
         }
 #if ENABLE_FEATURE_CLEAN_UP
         fclose(procpt);