Bug#632832: ufsutils: growfs.ufs do not work

[Nikos Skalkotos <skalkoto@grnet.gr>]

Hello all,

The " bogus sectorsize: 0" error is because the get_dev_size() function
in growfs.c only works when using the FreeBSD kernel. The sectorsize and
mediasize local variables get initialized only if HAVE_BSD_DISKLABEL is
defined, and this gets defined only when compiling the source under
Debian GNU/kFreeBSD.

Please find attached a patch that makes the function work under Linux
too. In order to accomplish this, the patch will add a
get_block_device_sectors() function under libport/blockdev.c. The
get_dev_size() function will call the latter if HAVE_BSD_DISKLABEL is
not defined.

The patch also adds a get_sector_size() function that returns the value
of the hard-coded sector_size variable that was already present in
libprot/blockdev.c.  This function is currently not being used, so feel
free to remove it if you want.

I'm not sure that hard-coding the sector_size is the right thing to do.
You can always ask the kernel for the sector size value by triggering an
appropriate ioctl system call:

ioctl(fd, DIOCGSECTORSIZE, &sectorsize) (for freeBSD)
ioctl(fd, BLKSSZGET, &sectorsize) (for Linux)

but I haven't changed this to make the patch as less intrusive as possible.

Regards,
Nikos Skalkotos

--- a/growfs.ufs/growfs.c
+++ b/growfs.ufs/growfs.c
@@ -1926,20 +1926,22 @@
 static void
 get_dev_size(int fd, int *size)
 {
+#ifdef HAVE_BSD_DISKLABEL
    int sectorsize;
    off_t mediasize;
 
-#ifdef HAVE_BSD_DISKLABEL
    if (ioctl(fd, DIOCGSECTORSIZE, &sectorsize) == -1)
         err(1,"DIOCGSECTORSIZE");
    if (ioctl(fd, DIOCGMEDIASIZE, &mediasize) == -1)
         err(1,"DIOCGMEDIASIZE");
-#endif
 
    if (sectorsize <= 0)
        errx(1, "bogus sectorsize: %d", sectorsize);
 
    *size = mediasize / sectorsize;
+#else
+   *size = get_block_device_sectors(fd);
+#endif
 }
 
 /* ************************************************************** main ***** */
--- a/include/port/blockdev.h
+++ b/include/port/blockdev.h
@@ -4,6 +4,8 @@
 #include <sys/types.h>
 
 int64_t get_block_device_size(int fd);
+int64_t get_block_device_sectors(int fd);
+int get_sector_size(int fd);
 
 #endif
 
--- a/libport/blockdev.c
+++ b/libport/blockdev.c
@@ -48,6 +48,16 @@
 
 static const int sector_size = 512;
 
+int
+get_sector_size(int fd)
+{
+	/* In Linux you can ask the OS for the sector size with this syscall:
+	 * ioctl(fd, BLKSSZGET, &sector_size)
+	 */
+	return sector_size;
+}
+
+
 int64_t
 get_block_device_size(int fd)
 {
@@ -90,3 +100,9 @@
 
 	return size;
 }
+
+int64_t
+get_block_device_sectors(int fd)
+{
+	return get_block_device_size(fd) / sector_size;
+}
--- a/growfs.ufs/Makefile
+++ b/growfs.ufs/Makefile
@@ -16,8 +16,8 @@
 endif
  
 WARNS = 6
-LDADD += -L../libufs -lufs
-INCLUDES =
+LDADD += -L../libufs -lufs -L../libport -lport
+INCLUDES = -I../include -include port/blockdev.h
 
 include ../Makefile.common