ELF relocations. Some relocation types do not have a named symbol associated with them. The design did not account for that case

3 files changed, 51 insertions, 7 deletions

diff --git a/nuttx/binfmt/libelf/libelf.h b/nuttx/binfmt/libelf/libelf.h
index e1382ee2d..4304e64f2 100644
--- a/nuttx/binfmt/libelf/libelf.h
+++ b/nuttx/binfmt/libelf/libelf.h
@@ -174,6 +174,12 @@ int elf_readsym(FAR struct elf_loadinfo_s *loadinfo, int index,
  *   0 (OK) is returned on success and a negated errno is returned on
  *   failure.
  *
+ *   EINVAL - There is something inconsistent in the symbol table (should only
+ *            happen if the file is corrupted)
+ *   ENOSYS - Symbol lies in common
+ *   ESRCH  - Symbol has no name
+ *   ENOENT - Symbol undefined and not provided via a symbol table
+ *
  ****************************************************************************/
 
 int elf_symvalue(FAR struct elf_loadinfo_s *loadinfo, FAR Elf32_Sym *sym,
diff --git a/nuttx/binfmt/libelf/libelf_bind.c b/nuttx/binfmt/libelf/libelf_bind.c
index 608f65ef7..58ceb148f 100644
--- a/nuttx/binfmt/libelf/libelf_bind.c
+++ b/nuttx/binfmt/libelf/libelf_bind.c
@@ -136,6 +136,7 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
   FAR Elf32_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info];
   Elf32_Rel       rel;
   Elf32_Sym       sym;
+  FAR Elf32_Sym  *psym;
   uintptr_t       addr;
   int             symidx;
   int             ret;
@@ -148,6 +149,8 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
 
   for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++)
     {
+      psym = &sym;
+
       /* Read the relocation entry into memory */
 
       ret = elf_readrel(loadinfo, relsec, i, &rel);
@@ -179,9 +182,28 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
       ret = elf_symvalue(loadinfo, &sym, exports, nexports);
       if (ret < 0)
         {
-          bdbg("Section %d reloc %d: Failed to get value of symbol[%d]: %d\n",
-               relidx, i, symidx, ret);
-          return ret;
+          /* The special error -ESRCH is returned only in one condition:  The
+           * symbol has no name.
+           *
+           * There are a few relocations for a few architectures that do
+           * no depend upon a named symbol.  We don't know if that is the
+           * case here, but we will use a NULL symbol pointer to indicate
+           * that case to up_relocate().  That function can then do what
+           * is best.
+           */
+
+          if (ret == -ESRCH)
+            {
+              bdbg("Section %d reloc %d: Undefined symbol[%d] has no name: %d\n",
+                  relidx, i, symidx, ret);
+              psym = NULL;
+            }
+          else
+            {
+              bdbg("Section %d reloc %d: Failed to get value of symbol[%d]: %d\n",
+                  relidx, i, symidx, ret);
+              return ret;
+            }
         }
 
       /* Calculate the relocation address. */
@@ -197,7 +219,7 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
 
       /* Now perform the architecture-specific relocation */
 
-      ret = up_relocate(&rel, &sym, addr);
+      ret = up_relocate(&rel, psym, addr);
       if (ret < 0)
         {
           bdbg("ERROR: Section %d reloc %d: Relocation failed: %d\n", ret);
diff --git a/nuttx/binfmt/libelf/libelf_symbols.c b/nuttx/binfmt/libelf/libelf_symbols.c
index bd7942a67..40831d2ec 100644
--- a/nuttx/binfmt/libelf/libelf_symbols.c
+++ b/nuttx/binfmt/libelf/libelf_symbols.c
@@ -1,7 +1,7 @@
 /****************************************************************************
  * binfmt/libelf/libelf_symbols.c
  *
- *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012, 2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -76,6 +76,10 @@
  *   0 (OK) is returned on success and a negated errno is returned on
  *   failure.
  *
+ *   EINVAL - There is something inconsistent in the symbol table (should only
+ *            happen if the file is corrupted).
+ *   ESRCH - Symbol has no name
+ *
  ****************************************************************************/
 
 static int elf_symname(FAR struct elf_loadinfo_s *loadinfo,
@@ -94,7 +98,7 @@ static int elf_symname(FAR struct elf_loadinfo_s *loadinfo,
   if (sym->st_name == 0)
     {
       bdbg("Symbol has no name\n");
-      return -ENOENT;
+      return -ESRCH;
     }
 
   offset = loadinfo->shdr[loadinfo->strtabidx].sh_offset + sym->st_name;
@@ -253,6 +257,12 @@ int elf_readsym(FAR struct elf_loadinfo_s *loadinfo, int index,
  *   0 (OK) is returned on success and a negated errno is returned on
  *   failure.
  *
+ *   EINVAL - There is something inconsistent in the symbol table (should only
+ *            happen if the file is corrupted).
+ *   ENOSYS - Symbol lies in common
+ *   ESRCH  - Symbol has no name
+ *   ENOENT - Symbol undefined and not provided via a symbol table
+ *
  ****************************************************************************/
 
 int elf_symvalue(FAR struct elf_loadinfo_s *loadinfo, FAR Elf32_Sym *sym,
@@ -269,7 +279,7 @@ int elf_symvalue(FAR struct elf_loadinfo_s *loadinfo, FAR Elf32_Sym *sym,
         /* NuttX ELF modules should be compiled with -fno-common. */
 
         bdbg("SHN_COMMON: Re-compile with -fno-common\n");
-        return -EINVAL;
+        return -ENOSYS;
       }
 
     case SHN_ABS:
@@ -287,6 +297,12 @@ int elf_symvalue(FAR struct elf_loadinfo_s *loadinfo, FAR Elf32_Sym *sym,
         ret = elf_symname(loadinfo, sym);
         if (ret < 0)
           {
+            /* There are a few relocations for a few architectures that do
+             * no depend upon a named symbol.  We don't know if that is the
+             * case here, but return and special error to the caller to
+             * indicate the nameless symbol.
+             */
+
             bdbg("SHN_UNDEF: Failed to get symbol name: %d\n", ret);
             return ret;
           }