From 14e5f5be6a45f6d238a47b117d9dc9e3eb36a380 Mon Sep 17 00:00:00 2001

From: Alan Modra <amodra@gmail.com>

Date: Sun, 8 Nov 2015 09:28:59 -0800

Subject: [PATCH 04/11] ELF unexec: Merge Alpha and MIPS COFF debug handling

* unexelf.c (unexec): Merge Alpha and MIPS COFF debug handling.

Don't find .mdebug section index, find the section in the loop.

Allow for unlikely possibility that .mdebug is located at sh_offset

before bss segment, by calculating move from difference in

sh_offset rather than just assuming new_data2_size.  Simplify

cbLineOffset handling.

---

 src/unexelf.c | 96 ++++++++++++++++++-----------------------------------------

 1 file changed, 29 insertions(+), 67 deletions(-)

diff --git a/src/unexelf.c b/src/unexelf.c

index d6c6648..0065491 100644

--- a/src/unexelf.c

+++ b/src/unexelf.c

@@ -660,9 +660,6 @@ unexec (const char *new_name, const char *old_name)

   ptrdiff_t n, nn;

   ptrdiff_t old_bss_index, old_sbss_index, old_plt_index;

   ptrdiff_t old_data_index, new_data2_index;

-#if defined _SYSTYPE_SYSV || defined __sgi

-  ptrdiff_t old_mdebug_index;

-#endif

   struct stat stat_buf;

   off_t old_file_size;

@@ -706,13 +703,6 @@ unexec (const char *new_name, const char *old_name)

   old_section_names = (char *) old_base

     + OLD_SECTION_H (old_file_h->e_shstrndx).sh_offset;

-  /* Find the mdebug section, if any.  */

-

-#if defined _SYSTYPE_SYSV || defined __sgi

-  old_mdebug_index = find_section (".mdebug", old_section_names,

-				   old_name, old_file_h, old_section_h, 1);

-#endif

-

   /* Find the old .bss section.  Figure out parameters of the new

      data2 and bss sections.  */

@@ -1055,51 +1045,31 @@ temacs:

       memcpy (new_shdr->sh_offset + new_base, src, new_shdr->sh_size);

-#if defined __alpha__ && !defined __OpenBSD__

-      /* Update Alpha COFF symbol table: */

-      if (strcmp (old_section_names + old_shdr->sh_name, ".mdebug") == 0)

-	{

-	  pHDRR symhdr = (pHDRR) (new_shdr->sh_offset + new_base);

-

-	  symhdr->cbLineOffset += new_data2_size;

-	  symhdr->cbDnOffset += new_data2_size;

-	  symhdr->cbPdOffset += new_data2_size;

-	  symhdr->cbSymOffset += new_data2_size;

-	  symhdr->cbOptOffset += new_data2_size;

-	  symhdr->cbAuxOffset += new_data2_size;

-	  symhdr->cbSsOffset += new_data2_size;

-	  symhdr->cbSsExtOffset += new_data2_size;

-	  symhdr->cbFdOffset += new_data2_size;

-	  symhdr->cbRfdOffset += new_data2_size;

-	  symhdr->cbExtOffset += new_data2_size;

-	}

-#endif /* __alpha__ && !__OpenBSD__ */

-

-#if defined (_SYSTYPE_SYSV)

-      if (new_shdr->sh_type == SHT_MIPS_DEBUG

-	  && old_mdebug_index != -1)

+#if (defined __alpha__ && !defined __OpenBSD__) || defined _SYSTYPE_SYSV

+      /* Update Alpha and MIPS COFF debug symbol table.  */

+      if (strcmp (old_section_names + new_shdr->sh_name, ".mdebug") == 0

+	  && new_shdr->sh_offset - old_shdr->sh_offset != 0

+#if defined _SYSTYPE_SYSV

+	  && new_shdr->sh_type == SHT_MIPS_DEBUG

+#endif

+	  )

 	{

-	  ptrdiff_t new_offset = new_shdr->sh_offset;

-	  ptrdiff_t old_offset = OLD_SECTION_H (old_mdebug_index).sh_offset;

-	  ptrdiff_t diff = new_offset - old_offset;

+	  ptrdiff_t diff = new_shdr->sh_offset - old_shdr->sh_offset;

 	  HDRR *phdr = (HDRR *) (new_shdr->sh_offset + new_base);

-	  if (diff)

-	    {

-	      phdr->cbLineOffset += diff;

-	      phdr->cbDnOffset   += diff;

-	      phdr->cbPdOffset   += diff;

-	      phdr->cbSymOffset  += diff;

-	      phdr->cbOptOffset  += diff;

-	      phdr->cbAuxOffset  += diff;

-	      phdr->cbSsOffset   += diff;

-	      phdr->cbSsExtOffset += diff;

-	      phdr->cbFdOffset   += diff;

-	      phdr->cbRfdOffset  += diff;

-	      phdr->cbExtOffset  += diff;

-	    }

+	  phdr->cbLineOffset += diff;

+	  phdr->cbDnOffset += diff;

+	  phdr->cbPdOffset += diff;

+	  phdr->cbSymOffset += diff;

+	  phdr->cbOptOffset += diff;

+	  phdr->cbAuxOffset += diff;

+	  phdr->cbSsOffset += diff;

+	  phdr->cbSsExtOffset += diff;

+	  phdr->cbFdOffset += diff;

+	  phdr->cbRfdOffset += diff;

+	  phdr->cbExtOffset += diff;

 	}

-#endif /* _SYSTYPE_SYSV */

+#endif /* __alpha__ || _SYSTYPE_SYSV */

 #if __sgi

       /* Adjust  the HDRR offsets in .mdebug and copy the

@@ -1110,7 +1080,8 @@ temacs:

 	 the ld bug that gets the line table in a hole in the

 	 elf file rather than in the .mdebug section proper.

 	 David Anderson. davea@sgi.com  Jan 16,1994.  */

-      if (n == old_mdebug_index)

+      if (strcmp (old_section_names + new_shdr->sh_name, ".mdebug") == 0

+	  && new_shdr->sh_offset - old_shdr->sh_offset != 0)

 	{

 #define MDEBUGADJUST(__ct,__fileaddr)		\

   if (n_phdrr->__ct > 0)			\

@@ -1120,7 +1091,7 @@ temacs:

 	  HDRR *o_phdrr = (HDRR *) ((byte *) old_base + old_shdr->sh_offset);

 	  HDRR *n_phdrr = (HDRR *) ((byte *) new_base + new_shdr->sh_offset);

-	  unsigned movement = new_data2_size;

+	  ptrdiff_t movement = new_shdr->sh_offset - old_shdr->sh_offset;

 	  MDEBUGADJUST (idnMax, cbDnOffset);

 	  MDEBUGADJUST (ipdMax, cbPdOffset);

@@ -1136,22 +1107,13 @@ temacs:

 	     requires special handling.  */

 	  if (n_phdrr->cbLine > 0)

 	    {

+	      n_phdrr->cbLineOffset += movement;

+

 	      if (o_phdrr->cbLineOffset > (old_shdr->sh_offset

 					   + old_shdr->sh_size))

-		{

-		  /* line data is in a hole in elf. do special copy and adjust

-		     for this ld mistake.

-		     */

-		  n_phdrr->cbLineOffset += movement;

-

-		  memcpy (n_phdrr->cbLineOffset + new_base,

-			  o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);

-		}

-	      else

-		{

-		  /* somehow line data is in .mdebug as it is supposed to be.  */

-		  MDEBUGADJUST (cbLine, cbLineOffset);

-		}

+		/* If not covered by section, it hasn't yet been copied.  */

+		memcpy (n_phdrr->cbLineOffset + new_base,

+			o_phdrr->cbLineOffset + old_base, n_phdrr->cbLine);

 	    }

 	}

 #endif /* __sgi */

-- 

2.7.4