From: Mark Wielaard <mark@klomp.org>
Date: Sat, 13 Jan 2018 13:33:50 +0000 (+0100)
Subject: Additional fix for gnu debug alt file resolving.
X-Git-Tag: VALGRIND_3_14_0~181
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d0403032250c8985ae99a96af7bcd9190ad654b;p=thirdparty%2Fvalgrind.git

Additional fix for gnu debug alt file resolving.

Also handle the case where the symlink itself contains a relative path.
Then we need to add the symlink dir before it.

https://bugs.kde.org/show_bug.cgi?id=387773
---

diff --git a/coregrind/m_debuginfo/readelf.c b/coregrind/m_debuginfo/readelf.c
index c19ff212b7..70c28e6292 100644
--- a/coregrind/m_debuginfo/readelf.c
+++ b/coregrind/m_debuginfo/readelf.c
@@ -1582,6 +1582,24 @@ static HChar* readlink_path (const HChar *path)
       return NULL;
    }
 
+  if (buf[0] == '/')
+    return buf;
+
+  /* Relative path, add link dir.  */
+  HChar *linkdirptr;
+  SizeT linkdir_len = VG_(strlen)(path);
+  if ((linkdirptr = VG_(strrchr)(path, '/')) != NULL)
+    linkdir_len -= VG_(strlen)(linkdirptr + 1);
+
+  SizeT buflen = VG_(strlen)(buf);
+  SizeT needed = linkdir_len + buflen + 1;
+  if (bufsiz < needed)
+    buf = ML_(dinfo_realloc)("readlink_path.linkdir", buf, needed);
+
+  VG_(memmove)(buf + linkdir_len, buf, buflen);
+  VG_(memcpy)(buf, path, linkdir_len);
+  buf[needed - 1] = '\0';
+
   return buf;
 }