libebl: Use elf_getshdrstrndx in ebl_section_strip_p.

The ebl_section_strip_p function used the Ehdr e_shstrndx field
to get at the name of the (debug) sections. This is not correct
if there are more than SHN_LORESERVE sections. Use elf_getshdrstrndx
to get at the shstrtab section. And drop the Ehdr argument that isn't
necessary anymore.

Signed-off-by: Mark Wielaard <mark@klomp.org>

6 files changed, 21 insertions, 7 deletions

diff --git a/libebl/ChangeLog b/libebl/ChangeLog
index 574aae6e..d36a2681 100644
--- a/libebl/ChangeLog
+++ b/libebl/ChangeLog
@@ -1,5 +1,11 @@
 2018-09-12  Mark Wielaard  <mark@klomp.org>
 
+	* eblsectionstripp.c (ebl_section_strip_p): Drop ehdr argument.
+	Use elf_getshdrstrndx.
+	* libebl.h (ebl_section_strip_p): Drop ehdr argument.
+
+2018-09-12  Mark Wielaard  <mark@klomp.org>
+
 	* ebl-hooks.h (check_special_symbol): Drop ehdr argument.
 	* ebl_check_special_symbol.c (ebl_check_special_symbol): Likewise.
 	* eblopenbackend.c (default_check_special_symbol): Likewise.
diff --git a/libebl/eblsectionstripp.c b/libebl/eblsectionstripp.c
index c6cda63a..a5624ffe 100644
--- a/libebl/eblsectionstripp.c
+++ b/libebl/eblsectionstripp.c
@@ -35,7 +35,7 @@
 
 
 bool
-ebl_section_strip_p (Ebl *ebl, const GElf_Ehdr *ehdr, const GElf_Shdr *shdr,
+ebl_section_strip_p (Ebl *ebl, const GElf_Shdr *shdr,
 		     const char *name, bool remove_comment,
 		     bool only_remove_debug)
 {
@@ -53,7 +53,10 @@ ebl_section_strip_p (Ebl *ebl, const GElf_Ehdr *ehdr, const GElf_Shdr *shdr,
 	  GElf_Shdr *shdr_l = gelf_getshdr (scn_l, &shdr_mem_l);
 	  if (shdr_l != NULL)
 	    {
-	      const char *s_l = elf_strptr (ebl->elf, ehdr->e_shstrndx,
+	      size_t shstrndx;
+	      if (elf_getshdrstrndx (ebl->elf, &shstrndx) != 0)
+		return false;
+	      const char *s_l = elf_strptr (ebl->elf, shstrndx,
 					    shdr_l->sh_name);
 	      if (s_l != NULL && ebl_debugscn_p (ebl, s_l))
 		return true;
diff --git a/libebl/libebl.h b/libebl/libebl.h
index 0e1f41be..5abc02d8 100644
--- a/libebl/libebl.h
+++ b/libebl/libebl.h
@@ -205,7 +205,7 @@ extern bool ebl_none_reloc_p (Ebl *ebl, int reloc);
 extern bool ebl_relative_reloc_p (Ebl *ebl, int reloc);
 
 /* Check whether section should be stripped.  */
-extern bool ebl_section_strip_p (Ebl *ebl, const GElf_Ehdr *ehdr,
+extern bool ebl_section_strip_p (Ebl *ebl,
 				 const GElf_Shdr *shdr, const char *name,
 				 bool remove_comment, bool only_remove_debug);
 
diff --git a/src/ChangeLog b/src/ChangeLog
index a118519f..7d046ec3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,10 @@
 2018-09-12  Mark Wielaard  <mark@klomp.org>
 
+	* elfcmp.c (main): Call ebl_section_strip_p without ehdr.
+	* strip.c (handle_elf): Likewise.
+
+2018-09-12  Mark Wielaard  <mark@klomp.org>
+
 	* elflint.c (check_symtab): Call ebl_check_special_symbol without
 	ehdr.
 
diff --git a/src/elfcmp.c b/src/elfcmp.c
index b40df8bf..b68df688 100644
--- a/src/elfcmp.c
+++ b/src/elfcmp.c
@@ -254,7 +254,7 @@ main (int argc, char *argv[])
 	    sname1 = elf_strptr (elf1, ehdr1->e_shstrndx, shdr1->sh_name);
 	}
       while (scn1 != NULL
-	     && ebl_section_strip_p (ebl1, ehdr1, shdr1, sname1, true, false));
+	     && ebl_section_strip_p (ebl1, shdr1, sname1, true, false));
 
       GElf_Shdr shdr2_mem;
       GElf_Shdr *shdr2;
@@ -267,7 +267,7 @@ main (int argc, char *argv[])
 	    sname2 = elf_strptr (elf2, ehdr2->e_shstrndx, shdr2->sh_name);
 	}
       while (scn2 != NULL
-	     && ebl_section_strip_p (ebl2, ehdr2, shdr2, sname2, true, false));
+	     && ebl_section_strip_p (ebl2, shdr2, sname2, true, false));
 
       if (scn1 == NULL || scn2 == NULL)
 	break;
diff --git a/src/strip.c b/src/strip.c
index 1367de77..dc712364 100644
--- a/src/strip.c
+++ b/src/strip.c
@@ -817,7 +817,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
     /* Check whether the section can be removed.  Since we will create
        a new .shstrtab assume it will be removed too.  */
     if (remove_shdrs ? !(shdr_info[cnt].shdr.sh_flags & SHF_ALLOC)
-	: (ebl_section_strip_p (ebl, ehdr, &shdr_info[cnt].shdr,
+	: (ebl_section_strip_p (ebl, &shdr_info[cnt].shdr,
 				shdr_info[cnt].name, remove_comment,
 				remove_debug)
 	   || cnt == ehdr->e_shstrndx
@@ -978,7 +978,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
 			   original table in the debug file.  Unless
 			   it is a redundant data marker to a debug
 			   (data only) section.  */
-			if (! (ebl_section_strip_p (ebl, ehdr,
+			if (! (ebl_section_strip_p (ebl,
 						    &shdr_info[scnidx].shdr,
 						    shdr_info[scnidx].name,
 						    remove_comment,