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

arch/arm/src/arm/up_elf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/arm/up_elf.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
@@ -132,6 +132,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *ehdr)
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value:
@@ -144,8 +148,19 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
                 uintptr_t addr)
 {
   int32_t offset;
+  unsigned int relotype;
 
-  switch (ELF32_R_TYPE(rel->r_info))
+  /* All relocations depend upon having valid symbol information */
+
+  relotype = ELF32_R_TYPE(rel->r_info);
+  if (sym == NULL && relotype != R_ARM_NONE)
+    {
+      return -EINVAL;
+    }
+
+  /* Handle the relocation by relocation type */
+
+  switch (relotype)
     {
     case R_ARM_NONE:
       {
@@ -254,4 +269,3 @@ int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym,
   bdbg("RELA relocation not supported\n");
   return -ENOSYS;
 }
-

arch/arm/src/armv6-m/up_elf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/armv6-m/up_elf.c
  *
- *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -124,6 +124,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *ehdr)
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value:
@@ -138,8 +142,21 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
   int32_t offset;
   uint32_t upper_insn;
   uint32_t lower_insn;
+  unsigned int relotype;
 
-  switch (ELF32_R_TYPE(rel->r_info))
+  /* All relocations except R_ARM_V4BX depend upon having valid symbol
+   * information.
+   */
+
+  relotype = ELF32_R_TYPE(rel->r_info);
+  if (sym == NULL && relotype != R_ARM_NONE && relotype != R_ARM_V4BX)
+    {
+      return -EINVAL;
+    }
+
+  /* Handle the relocation by relocation type */
+
+  switch (relotype)
     {
     case R_ARM_NONE:
       {
@@ -447,4 +464,3 @@ int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym,
   bdbg("RELA relocation not supported\n");
   return -ENOSYS;
 }
-

arch/arm/src/armv7-a/arm_elf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/armv-7a/arm_elf.c
  *
- *   Copyright (C) 2013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2013-2014 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -132,6 +132,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *ehdr)
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value:
@@ -144,8 +148,21 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
                 uintptr_t addr)
 {
   int32_t offset;
+  unsigned int relotype;
 
-  switch (ELF32_R_TYPE(rel->r_info))
+  /* All relocations except R_ARM_V4BX depend upon having valid symbol
+   * information.
+   */
+
+  relotype = ELF32_R_TYPE(rel->r_info);
+  if (sym == NULL && relotype != R_ARM_NONE && relotype != R_ARM_V4BX)
+    {
+      return -EINVAL;
+    }
+
+  /* Handle the relocation by relocation type */
+
+  switch (relotype)
     {
     case R_ARM_NONE:
       {
@@ -254,4 +271,3 @@ int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym,
   bdbg("RELA relocation not supported\n");
   return -ENOSYS;
 }
-

arch/arm/src/armv7-m/up_elf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/arm/src/armv7-m/up_elf.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
@@ -124,6 +124,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *ehdr)
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value:
@@ -138,8 +142,21 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
   int32_t offset;
   uint32_t upper_insn;
   uint32_t lower_insn;
+  unsigned int relotype;
 
-  switch (ELF32_R_TYPE(rel->r_info))
+  /* All relocations except R_ARM_V4BX depend upon having valid symbol
+   * information.
+   */
+
+  relotype = ELF32_R_TYPE(rel->r_info);
+  if (sym == NULL && relotype != R_ARM_NONE && relotype != R_ARM_V4BX)
+    {
+      return -EINVAL;
+    }
+
+  /* Handle the relocation by relocation type */
+
+  switch (relotype)
     {
     case R_ARM_NONE:
       {
@@ -447,4 +464,3 @@ int up_relocateadd(FAR const Elf32_Rela *rel, FAR const Elf32_Sym *sym,
   bdbg("RELA relocation not supported\n");
   return -ENOSYS;
 }
-

arch/sim/src/up_elf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/sim/src/up_elf.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
@@ -100,6 +100,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *hdr)
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value:
@@ -113,6 +117,15 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
 {
   FAR uint32_t *ptr = (FAR uint32_t *)addr;
 
+  /* All relocations depend upon having valid symbol information. */
+
+  if (sym == NULL)
+    {
+      return -EINVAL;
+    }
+
+  /* Handle the relocation by relocation type */
+
   switch (ELF32_R_TYPE(rel->r_info))
     {
      case R_386_32:
@@ -124,7 +137,7 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
        break;
 
      default:
-        return -EINVAL;
+       return -EINVAL;
     }
 
   return OK;

arch/x86/src/common/up_elf.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * arch/x86/src/up_elf.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
@@ -100,6 +100,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *hdr)
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value:
@@ -113,6 +117,15 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
 {
   FAR uint32_t *ptr = (FAR uint32_t *)addr;
 
+  /* All relocations depend upon having valid symbol information. */
+
+  if (sym == NULL)
+    {
+      return -EINVAL;
+    }
+
+  /* Handle the relocation by relocation type */
+
   switch (ELF32_R_TYPE(rel->r_info))
     {
      case R_386_32:
@@ -124,7 +137,7 @@ int up_relocate(FAR const Elf32_Rel *rel, FAR const Elf32_Sym *sym,
        break;
 
      default:
-        return -EINVAL;
+       return -EINVAL;
     }
 
   return OK;

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,

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",
+          /* The special error -ESRCH is returned only in one condition:  The
-               relidx, i, symidx, ret);
+           * symbol has no name.
-          return ret;
+           *
+           * 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);

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;
           }

include/nuttx/binfmt/elf.h

@@ -1,7 +1,7 @@
 /****************************************************************************
  * include/nuttx/binfmt/elf.h
  *
- *   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
@@ -303,6 +303,10 @@ bool up_checkarch(FAR const Elf32_Ehdr *hdr);
  * Input Parameters:
  *   rel - The relocation type
  *   sym - The ELF symbol structure containing the fully resolved value.
+ *         There are a few relocation types for a few architectures that do
+ *         not require symbol information.  For those, this value will be
+ *         NULL.  Implementations of these functions must be able to handle
+ *         that case.
  *   addr - The address that requires the relocation.
  *
  * Returned Value: