strip: --reloc-debug-sections, relocate against any debug section symbol.

diff --git a/src/ChangeLog b/src/ChangeLog
index 0d28013..007236a 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,13 @@
 2011-05-23  Mark Wielaard  <mjw@redhat.com>
 
+       * strip.c (relocate): Take new arguments is_rela to indicate
+       whether the relocation is from a SHT_REL or SHT_RELA section. 
+       Relocate against any debug section symbol, not just STT_SECTION
+       symbols. For SHT_REL relocations, fetch addend from offset and
+       add it to symbol value if not zero.
+
+2011-05-23  Mark Wielaard  <mjw@redhat.com>
+
        * strip.c (OPT_RELOC_DEBUG): New option.
        (argp_option): Add new --reloc-debug-sections option.
        (main): Check new option.

diff --git a/src/strip.c b/src/strip.c
index f680061..cf6bd97 100644 (file)
--- a/src/strip.c
+++ b/src/strip.c
@@ -1682,7 +1682,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
              /* Apply one relocation.  Returns true when trivial
                 relocation actually done.  */
              bool relocate (GElf_Addr offset, const GElf_Sxword addend,
-                            int rtype, int symndx)
+                            bool is_rela, int rtype, int symndx)
              {
                /* R_*_NONE relocs can always just be removed.  */
                if (rtype == 0)
@@ -1704,80 +1704,98 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
                GElf_Sym *sym = gelf_getsymshndx (symdata, xndxdata,
                                                  symndx, &sym_mem,
                                                  &xndx);
-               if (GELF_ST_TYPE (sym->st_info) == STT_SECTION)
+               Elf32_Word sec = (sym->st_shndx == SHN_XINDEX
+                                 ? xndx : sym->st_shndx);
+               if (ebl_debugscn_p (ebl, shdr_info[sec].name))
                  {
-                   Elf32_Word sec = (sym->st_shndx == SHN_XINDEX
-                                     ? xndx : sym->st_shndx);
-                   if (ebl_debugscn_p (ebl, shdr_info[sec].name))
-                     {
-                       size_t size;
-                       switch (type)
-                         {
-#define DO_TYPE(NAME, Name)                                    \
-                           case ELF_T_##NAME:                  \
-                             size = sizeof (GElf_##Name);      \
-                             break;
-                           TYPES;
-#undef DO_TYPE
-                         default:
-                           return false;
-                         }
-
-                       if (offset + size > tdata->d_size)
-                         error (0, 0, gettext ("bad relocation"));
-
-                       /* For SHT_REL sections this is all that needs
-                          to be checked.  The addend is contained in
-                          the original data at the offset already.
-                          And the (section) symbol address is zero.
-                          So just remove the relocation, it isn't
-                          needed anymore.  */
-                       if (addend == 0)
-                         return true;
+                   size_t size;
 
 #define DO_TYPE(NAME, Name) GElf_##Name Name;
-                       union { TYPES; } tmpbuf;
+                   union { TYPES; } tmpbuf;
 #undef DO_TYPE
-                       Elf_Data tmpdata =
-                         {
-                           .d_type = type,
-                           .d_buf = &tmpbuf,
-                           .d_size = size,
-                           .d_version = EV_CURRENT,
-                         };
-                       Elf_Data rdata =
-                         {
-                           .d_type = type,
-                           .d_buf = tdata->d_buf + offset,
-                           .d_size = size,
-                           .d_version = EV_CURRENT,
-                         };
 
-                       /* For SHT_RELA sections we just take the
-                          addend and put it into the relocation slot.
-                          The (section) symbol address can be
-                          ignored, since it is zero.  */
-                       switch (type)
-                         {
+                   switch (type)
+                     {
 #define DO_TYPE(NAME, Name)                            \
-                           case ELF_T_##NAME:          \
-                             tmpbuf.Name = addend;     \
-                             break;
-                           TYPES;
+                       case ELF_T_##NAME:              \
+                         size = sizeof (GElf_##Name);  \
+                         tmpbuf.Name = 0;              \
+                         break;
+                       TYPES;
 #undef DO_TYPE
-                         default:
-                           abort ();
-                         }
+                     default:
+                       return false;
+                     }
+
+                   if (offset + size > tdata->d_size)
+                     error (0, 0, gettext ("bad relocation"));
 
-                       Elf_Data *s = gelf_xlatetof (debugelf, &rdata,
-                                                    &tmpdata,
+                   /* When the symbol value is zero then for SHT_REL
+                      sections this is all that needs to be checked.
+                      The addend is contained in the original data at
+                      the offset already.  So if the (section) symbol
+                      address is zero and the given addend is zero
+                      just remove the relocation, it isn't needed
+                      anymore.  */
+                   if (addend == 0 && sym->st_value == 0)
+                     return true;
+
+                   Elf_Data tmpdata =
+                     {
+                       .d_type = type,
+                       .d_buf = &tmpbuf,
+                       .d_size = size,
+                       .d_version = EV_CURRENT,
+                     };
+                   Elf_Data rdata =
+                     {
+                       .d_type = type,
+                       .d_buf = tdata->d_buf + offset,
+                       .d_size = size,
+                       .d_version = EV_CURRENT,
+                     };
+
+                   GElf_Addr value = sym->st_value;
+                   if (is_rela)
+                     {
+                       /* For SHT_RELA sections we just take the
+                          given addend and add it to the value.  */
+                       value += addend;
+                     }
+                   else
+                     {
+                       /* For SHT_REL sections we have to peek at
+                          what is already in the section at the given
+                          offset to get the addend.  */
+                       Elf_Data *d = gelf_xlatetom (debugelf, &tmpdata,
+                                                    &rdata,
                                                     ehdr->e_ident[EI_DATA]);
-                       if (s == NULL)
+                       if (d == NULL)
                          INTERNAL_ERROR (fname);
-                       assert (s == &rdata);
+                       assert (d == &tmpdata);
+                     }
 
-                       return true;
+                   switch (type)
+                     {
+#define DO_TYPE(NAME, Name)                                    \
+                       case ELF_T_##NAME:                      \
+                         tmpbuf.Name += (GElf_##Name) value;   \
+                         break;
+                       TYPES;
+#undef DO_TYPE
+                     default:
+                       abort ();
                      }
+
+                   /* Now finally put in the new value.  */
+                   Elf_Data *s = gelf_xlatetof (debugelf, &rdata,
+                                                &tmpdata,
+                                                ehdr->e_ident[EI_DATA]);
+                   if (s == NULL)
+                     INTERNAL_ERROR (fname);
+                   assert (s == &rdata);
+
+                   return true;
                  }
                return false;
              }
@@ -1789,7 +1807,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
                  {
                    GElf_Rel rel_mem;
                    GElf_Rel *r = gelf_getrel (reldata, relidx, &rel_mem);
-                   if (! relocate (r->r_offset, 0,
+                   if (! relocate (r->r_offset, 0, false,
                                    GELF_R_TYPE (r->r_info),
                                    GELF_R_SYM (r->r_info)))
                      {
@@ -1803,7 +1821,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const char *fname,
                  {
                    GElf_Rela rela_mem;
                    GElf_Rela *r = gelf_getrela (reldata, relidx, &rela_mem);
-                   if (! relocate (r->r_offset, r->r_addend,
+                   if (! relocate (r->r_offset, r->r_addend, true,
                                    GELF_R_TYPE (r->r_info),
                                    GELF_R_SYM (r->r_info)))
                      {