From: Julian Seward <jseward@acm.org>
Date: Mon, 28 Mar 2011 08:22:55 +0000 (+0000)
Subject: Intercept strlen in ld.so on x86.  Fixes #266961.
X-Git-Tag: svn/VALGRIND_3_7_0~566
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc53563392f7b7b53623908084f608ff3ac310ee;p=thirdparty%2Fvalgrind.git

Intercept strlen in ld.so on x86.  Fixes #266961.
(Jakub Jelinek, jakub@redhat.com)


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11668
---

diff --git a/coregrind/m_redir.c b/coregrind/m_redir.c
index 065b61aa07..b45b03ece0 100644
--- a/coregrind/m_redir.c
+++ b/coregrind/m_redir.c
@@ -924,20 +924,23 @@ void VG_(redir_initialise) ( void )
    /* If we're using memcheck, use this intercept right from the
       start, otherwise ld.so (glibc-2.3.5) makes a lot of noise. */
    if (0==VG_(strcmp)("Memcheck", VG_(details).name)) {
+      const HChar** mandatory;
+#     if defined(GLIBC_2_2) || defined(GLIBC_2_3) || defined(GLIBC_2_4) \
+         || defined(GLIBC_2_5) || defined(GLIBC_2_6) || defined(GLIBC_2_7) \
+         || defined(GLIBC_2_8) || defined(GLIBC_2_9) \
+         || defined(GLIBC_2_10) || defined(GLIBC_2_11)
+      mandatory = NULL;
+#     else
+      /* for glibc-2.12 and later, this is mandatory - can't sanely
+         continue without it */
+      mandatory = complain_about_stripped_glibc_ldso;
+#     endif
       add_hardwired_spec(
          "ld-linux.so.2", "index",
-         (Addr)&VG_(x86_linux_REDIR_FOR_index),
-#        if defined(GLIBC_2_2) || defined(GLIBC_2_3) || defined(GLIBC_2_4) \
-            || defined(GLIBC_2_5) || defined(GLIBC_2_6) || defined(GLIBC_2_7) \
-            || defined(GLIBC_2_8) || defined(GLIBC_2_9) \
-            || defined(GLIBC_2_10) || defined(GLIBC_2_11)
-         NULL
-#        else
-         /* for glibc-2.12 and later, this is mandatory - can't sanely
-            continue without it */
-         complain_about_stripped_glibc_ldso
-#        endif
-      );
+         (Addr)&VG_(x86_linux_REDIR_FOR_index), mandatory);
+      add_hardwired_spec(
+         "ld-linux.so.2", "strlen",
+         (Addr)&VG_(x86_linux_REDIR_FOR_strlen), mandatory);
    }
 
 #  elif defined(VGP_amd64_linux)
diff --git a/coregrind/m_trampoline.S b/coregrind/m_trampoline.S
index 0fdcf9e83f..eefdbfce0a 100644
--- a/coregrind/m_trampoline.S
+++ b/coregrind/m_trampoline.S
@@ -112,6 +112,27 @@ VG_(x86_linux_REDIR_FOR_index):
         ret
 .size VG_(x86_linux_REDIR_FOR_index), .-VG_(x86_linux_REDIR_FOR_index)
 
+/* There's no particular reason that this needs to be handwritten
+   assembly, but since that's what this file contains, here's a
+   simple strlen implementation (written in C and compiled by gcc.)
+*/
+.global VG_(x86_linux_REDIR_FOR_strlen)
+.type   VG_(x86_linux_REDIR_FOR_strlen), @function
+VG_(x86_linux_REDIR_FOR_strlen):
+        pushl   %ebp
+        movl    %esp, %ebp
+        movl    8(%ebp), %edx
+        movl    %edx, %eax
+        jmp     2f
+1:      incl    %eax
+2:      cmpb    $0, (%eax)
+        jne     1b
+        subl    %edx, %eax
+        popl    %ebp
+        ret
+.size VG_(x86_linux_REDIR_FOR_strlen), .-VG_(x86_linux_REDIR_FOR_strlen)
+
+
 .global VG_(trampoline_stuff_end)
 VG_(trampoline_stuff_end):
 
diff --git a/coregrind/pub_core_trampoline.h b/coregrind/pub_core_trampoline.h
index 5eafcbbf7d..aee983c1b7 100644
--- a/coregrind/pub_core_trampoline.h
+++ b/coregrind/pub_core_trampoline.h
@@ -60,6 +60,7 @@ extern Addr VG_(trampoline_stuff_end);
 extern Addr VG_(x86_linux_SUBST_FOR_sigreturn);
 extern Addr VG_(x86_linux_SUBST_FOR_rt_sigreturn);
 extern Char* VG_(x86_linux_REDIR_FOR_index) ( const Char*, Int );
+extern UInt VG_(x86_linux_REDIR_FOR_strlen)( void* );
 #endif
 
 #if defined(VGP_amd64_linux)