dracut-install: ln_r() is deficient

[marcosfrm]

When dracut_install() calls ln_r(), full paths are passed. For example:

'/home/marcos/temp/test/lib64/libgcrypt.so.20.4.1' '/home/marcos/temp/test/lib64/libgcrypt.so.20'

Then, convert_abs_rel() transforms /home/marcos/temp/test/lib64/libgcrypt.so.20.4.1 into ../../lib64/libgcrypt.so.20.4.1:

dracut-install: ln -s '../../lib64/libgcrypt.so.20.4.1' '/home/marcos/temp/test/lib64/libgcrypt.so.20'

$ ls -l '/home/marcos/temp/test/lib64/libgcrypt.so.20'
lrwxrwxrwx. 1 marcos marcos 31 abr 10 15:36 /home/marcos/temp/test/lib64/libgcrypt.so.20 -> ../../lib64/libgcrypt.so.20.4.1

coreutils' ln -r does a better job, without ../../lib64/ in the target:

$ ln -sfr '/home/marcos/temp/test/lib64/libgcrypt.so.20.4.1' '/home/marcos/temp/test/lib64/libgcrypt.so.20'
$ ls -l '/home/marcos/temp/test/lib64/libgcrypt.so.20'
lrwxrwxrwx. 1 marcos marcos 19 abr 10 15:39 /home/marcos/temp/test/lib64/libgcrypt.so.20 -> libgcrypt.so.20.4.1

[marcosfrm]

lib64 is a link to usr/lib64:

$ ls -l /home/marcos/temp/test/lib64
lrwxrwxrwx. 1 marcos marcos 9 abr 10 15:39 /home/marcos/temp/test/lib64 -> usr/lib64

but it does not matter (or it should not...).

[marcosfrm]

diff --git a/src/install/dracut-install.c b/src/install/dracut-install.c
index 7c6d91c1..b4f5935b 100644
--- a/src/install/dracut-install.c
+++ b/src/install/dracut-install.c
@@ -165,7 +165,7 @@ static char *convert_abs_rel(const char *from, const char *target)
         char relative_from[MAXPATHLEN * 4];
         _cleanup_free_ char *realtarget = NULL;
         _cleanup_free_ char *target_dir_p = NULL, *realpath_p = NULL;
-        const char *realfrom = from;
+        const char *realfrom = realpath(from, NULL);
         size_t level = 0, fromlevel = 0, targetlevel = 0;
         int l;
         size_t i, rl, dirlen;

Appears to work. target was canonicalized while from was not. (Edit: quick-and-dirty patch, leaks memory)