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From: Maxim Kuvyrkov <maxim@codesourcery.com>
To: Mark Hatle <mark.hatle@windriver.com>
Cc: <prelink@sourceware.org>
Subject: [PATCH, cross prelink] 0001-Pull-ld.so-s-name-from-PT_INTERP-to-avoid-the-runtim.patch
Date: Tue, 10 Apr 2012 19:28:00 -0000	[thread overview]
Message-ID: <78E2B6DA-6156-43B6-B788-C8501057C234@codesourcery.com> (raw)

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Mark,

This patch makes rtld emulator in cross prelink use ld.so's name as it is encoded in PT_INTERP header.

Currently, rtld emulator returns "lib/ld.so.1" for runtime linker's name, but the linker actually expects "/lib/ld.so.1" -- that one slash at the beginning causes prelink checks done by the runtime linker to fail and not use prelink information.

The runtime linker sets up a map for itself under the name stored in PT_INTERP header of the executable, and this patch makes rtld emulator follow the suit.

I have tested this patch using a different version of rtld emulator (the one that CodeSourcery / Mentor maintains), but the function in question is the same in both, so this patch is also relevant for Yocto's prelink.

Any comments?  Please merge at your leisure.

Thank you,

--
Maxim Kuvyrkov
CodeSourcery / Mentor Graphics


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From 0065267a94585689628087dbd656ad1b2b20c952 Mon Sep 17 00:00:00 2001
From: Maxim Kuvyrkov <maxim@codesourcery.com>
Date: Tue, 10 Apr 2012 12:15:02 -0700
Subject: [PATCH] Pull ld.so's name from PT_INTERP to avoid the runtime linker failing to use
 prelink information due to name mismatch.

	* src/rtld/rtld.c (find_lib_by_soname): Follow ld.so's behavior of
	pulling its name from PT_INTERP.

Signed-off-by: Maxim Kuvyrkov <maxim@codesourcery.com>
---
 trunk/ChangeLog.cross |    4 ++++
 trunk/src/rtld/rtld.c |   28 ++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/trunk/ChangeLog.cross b/trunk/ChangeLog.cross
index d802a60..24b5d5c 100644
--- a/trunk/ChangeLog.cross
+++ b/trunk/ChangeLog.cross
@@ -1,3 +1,7 @@
+2012-04-10  Maxim Kuvyrkov  <maxim@codesourcery.com>
+	* src/rtld/rtld.c (find_lib_by_soname): Follow ld.so's behavior of
+	pulling its name from PT_INTERP.
+
 2012-04-04  Mark Hatle <mark.hatle@windriver.com>
 	* testsuite/ifunc1.sh, ifunc2.sh, ifunc3.sh: Add cross compilation
 	  checks to a few of the test cases.
diff --git a/trunk/src/rtld/rtld.c b/trunk/src/rtld/rtld.c
index 8121493..b6bcef3 100644
--- a/trunk/src/rtld/rtld.c
+++ b/trunk/src/rtld/rtld.c
@@ -497,6 +497,34 @@ find_lib_by_soname (const char *soname, struct dso_list *loader,
   if (strchr (soname, '/'))
     return strdup (soname);
 
+  if (is_ldso_soname (soname))
+    /* For dynamic linker, pull the path out of PT_INTERP header.
+       When loading an executable the dynamic linker creates an entry for
+       itself under the name stored in PT_INTERP, and the name that we
+       record in .gnu.liblist should match that exactly.  */
+    {
+      struct dso_list *loader_p = loader;
+
+      while (loader_p)
+	{
+	  if (loader_p->dso->ehdr.e_type == ET_EXEC)
+	    {
+	      int i;
+
+	      for (i = 0; i < loader_p->dso->ehdr.e_phnum; ++i)
+		if (loader_p->dso->phdr[i].p_type == PT_INTERP)
+		  {
+		    const char *interp;
+		    interp = get_data (loader_p->dso,
+				       loader_p->dso->phdr[i].p_vaddr,
+				       NULL, NULL);
+		    return strdup (interp);
+		  }
+	    }
+	  loader_p = loader_p->loader;
+	}
+    }
+
   if (loader->dso->info[DT_RUNPATH] == 0)
     {
       /* Search DT_RPATH all the way up.  */
-- 
1.7.0.4


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             reply	other threads:[~2012-04-10 19:28 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-10 19:28 Maxim Kuvyrkov [this message]
2012-04-10 19:46 ` Mark Hatle
2012-04-10 19:57   ` Maxim Kuvyrkov
2012-04-10 20:23     ` Mark Hatle
2012-05-26  3:42       ` Maxim Kuvyrkov
2012-05-29 15:17         ` Mark Hatle
2012-06-27 22:34           ` Maxim Kuvyrkov
2012-06-28  2:29             ` Mark Hatle

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