C++ constructors work with ELF load now

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5273 42af7a65-404d-4744-a932-0658087f49c3

8 files changed, 406 insertions, 312 deletions

diff --git a/nuttx/binfmt/libelf/Kconfig b/nuttx/binfmt/libelf/Kconfig
index 5dc4a2d9f..f6f579276 100644
--- a/nuttx/binfmt/libelf/Kconfig
+++ b/nuttx/binfmt/libelf/Kconfig
@@ -32,13 +32,6 @@ config ELF_BUFFERINCR
 		will need to be read (such as symbol names).  This value specifies the size
 		increment to use each time the buffer is reallocated.  Default: 32
 
-config ELF_CONSTRUCTORS
-	bool "C++ Static Constructor Support"
-	default n
-	depends on HAVE_CXX
-	---help---
-		Build in support for C++ constructors in ELF modules.
-
 config ELF_DUMPBUFFER
 	bool "Dump ELF buffers"
 	default n
diff --git a/nuttx/binfmt/libelf/Make.defs b/nuttx/binfmt/libelf/Make.defs
index cf2507a99..26198ade2 100644
--- a/nuttx/binfmt/libelf/Make.defs
+++ b/nuttx/binfmt/libelf/Make.defs
@@ -41,11 +41,11 @@ BINFMT_CSRCS += elf.c
 
 # ELF library
 
-BINFMT_CSRCS += libelf_init.c libelf_uninit.c libelf_load.c \
-			   libelf_unload.c libelf_verify.c libelf_read.c \
-			   libelf_bind.c libelf_symbols.c libelf_iobuffer.c
+BINFMT_CSRCS += libelf_bind.c libelf_init.c libelf_iobuffer.c libelf_load.c \
+			    libelf_read.c libelf_sections.c libelf_symbols.c libelf_uninit.c \
+			    libelf_unload.c libelf_verify.c
 
-ifeq ($(CONFIG_ELF_CONSTRUCTORS),y)
+ifeq ($(CONFIG_BINFMT_CONSTRUCTORS),y)
 BINFMT_CSRCS += libelf_ctors.c
 endif
 
diff --git a/nuttx/binfmt/libelf/libelf.h b/nuttx/binfmt/libelf/libelf.h
index 0d13515cc..bea92496a 100644
--- a/nuttx/binfmt/libelf/libelf.h
+++ b/nuttx/binfmt/libelf/libelf.h
@@ -86,6 +86,39 @@ int elf_read(FAR struct elf_loadinfo_s *loadinfo, FAR uint8_t *buffer,
              size_t readsize, off_t offset);
 
 /****************************************************************************
+ * Name: elf_loadshdrs
+ *
+ * Description:
+ *   Loads section headers into memory.
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
+ ****************************************************************************/
+
+int elf_loadshdrs(FAR struct elf_loadinfo_s *loadinfo);
+
+/****************************************************************************
+ * Name: elf_findsection
+ *
+ * Description:
+ *   A section by its name.
+ *
+ * Input Parameters:
+ *   loadinfo - Load state information
+ *   sectname - Name of the section to find
+ *
+ * Returned Value:
+ *   On success, the index to the section is returned; A negated errno value
+ *   is returned on failure.
+ *
+ ****************************************************************************/
+
+int elf_findsection(FAR struct elf_loadinfo_s *loadinfo,
+                    FAR const char *sectname);
+
+/****************************************************************************
  * Name: elf_findsymtab
  *
  * Description:
@@ -199,27 +232,8 @@ int elf_reallocbuffer(FAR struct elf_loadinfo_s *loadinfo, size_t increment);
  *
  ****************************************************************************/
 
-#ifdef CONFIG_ELF_CONSTRUCTORS
+#ifdef CONFIG_BINFMT_CONSTRUCTORS
 int elf_loadctors(FAR struct elf_loadinfo_s *loadinfo);
 #endif
 
-/****************************************************************************
- * Name: elf_doctors
- *
- * Description:
- *   Execute C++ static constructors.
- *
- * Input Parameters:
- *   loadinfo - Load state information
- *
- * Returned Value:
- *   0 (OK) is returned on success and a negated errno is returned on
- *   failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_ELF_CONSTRUCTORS
-int elf_doctors(FAR struct elf_loadinfo_s *loadinfo);
-#endif
-
 #endif /* __BINFMT_LIBELF_LIBELF_H */
diff --git a/nuttx/binfmt/libelf/libelf_ctors.c b/nuttx/binfmt/libelf/libelf_ctors.c
index c53923d44..a57fc37d9 100644
--- a/nuttx/binfmt/libelf/libelf_ctors.c
+++ b/nuttx/binfmt/libelf/libelf_ctors.c
@@ -49,7 +49,7 @@
 
 #include "libelf.h"
 
-#ifdef CONFIG_ELF_CONSTRUCTORS
+#ifdef CONFIG_BINFMT_CONSTRUCTORS
 
 /****************************************************************************
  * Pre-Processor Definitions
@@ -68,166 +68,6 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: elf_sectname
- *
- * Description:
- *   Get the symbol name in loadinfo->iobuffer[].
- *
- * Returned Value:
- *   0 (OK) is returned on success and a negated errno is returned on
- *   failure.
- *
- ****************************************************************************/
-
-static inline int elf_sectname(FAR struct elf_loadinfo_s *loadinfo,
-                               FAR const Elf32_Shdr *shdr)
-{
-  FAR Elf32_Shdr *shstr;
-  FAR uint8_t *buffer;
-  off_t  offset;
-  size_t readlen;
-  size_t bytesread;
-  int shstrndx;
-  int ret;
-
-  /* Get the section header table index of the entry associated with the
-   * section name string table. If the file has no section name string table,
-   * this member holds the value SH_UNDEF.
-   */
-
-  shstrndx = loadinfo->ehdr.e_shstrndx;
-  if (shstrndx == SHN_UNDEF)
-    {
-      bdbg("No section header string table\n");
-      return -EINVAL;
-    }
-
-  /* Get the section name string table section header */
-
-  shstr = &loadinfo->shdr[shstrndx];
-
-  /* Get the file offset to the string that is the name of the section. This
-   * is the sum of:
-   *
-   *   shstr->sh_offset: The file offset to the first byte of the section
-   *     header string table data.
-   *   shdr->sh_name: The offset to the name of the section in the section
-   *     name table
-   */
-
-  offset = shstr->sh_offset + shdr->sh_name;
-
-  /* Loop until we get the entire section name into memory */
-
-  buffer    = loadinfo->iobuffer;
-  bytesread = 0;
-
-  for (;;)
-    {
-      /* Get the number of bytes to read */
-
-      readlen = loadinfo->buflen - bytesread;
-      if (offset + readlen > loadinfo->filelen)
-        {
-          readlen = loadinfo->filelen - offset;
-          if (readlen <= 0)
-            {
-              bdbg("At end of file\n");
-              return -EINVAL;
-            }
-        }
-
-      /* Read that number of bytes into the array */
-
-      buffer = &loadinfo->iobuffer[bytesread];
-      ret = elf_read(loadinfo, buffer, readlen, offset);
-      if (ret < 0)
-        {
-          bdbg("Failed to read section name\n");
-          return ret;
-        }
-
-      bytesread += readlen;
-
-      /* Did we read the NUL terminator? */
-
-      if (memchr(buffer, '\0', readlen) != NULL)
-        {
-          /* Yes, the buffer contains a NUL terminator. */
-
-          return OK;
-        }
-
-      /* No.. then we have to read more */
-
-      ret = elf_reallocbuffer(loadinfo, CONFIG_ELF_BUFFERINCR);
-      if (ret < 0)
-        {
-          bdbg("elf_reallocbuffer failed: %d\n", ret);
-          return ret;
-        }
-    }
-
-  /* We will not get here */
-
-  return OK;
-}
-
-/****************************************************************************
- * Name: elf_findctors
- *
- * Description:
- *   Find C++ static constructors.
- *
- * Input Parameters:
- *   loadinfo - Load state information
- *
- * Returned Value:
- *   On success, the index to the CTOR section is returned; A negated errno
- *   value is returned on failure.
- *
- ****************************************************************************/
-
-static inline int elf_findctors(FAR struct elf_loadinfo_s *loadinfo)
-{
-  FAR const Elf32_Shdr *shdr;
-  int ret;
-  int i;
-
-  /* Search through the shdr[] array in loadinfo for a section named .ctors */
-
-  for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
-    {
-      /* Get the name of this section */
-
-      shdr = &loadinfo->shdr[i];
-      ret  = elf_sectname(loadinfo, shdr);
-      if (ret < 0)
-        {
-          bdbg("elf_sectname failed: %d\n", ret);
-          return ret;
-        }
- 
-      /* Check if the name of this section if ".ctors" */
-
-      bvdbg("%d. Comparing \"%s\" and .ctors\"\n", i, loadinfo->iobuffer);
-
-      if (strcmp(".ctors", (FAR const char *)loadinfo->iobuffer) == 0)
-        {
-          /* We found it... return the index */
-
-          return i;
-        }
-    }
-
-  /* We failed to find the .ctors sections.  This may not be an error; maybe
-   * there are no static constructors.
-   */
-
-  return -ENOENT;
-}
-
-/****************************************************************************
  * Public Functions
  ****************************************************************************/
 
@@ -267,16 +107,21 @@ int elf_loadctors(FAR struct elf_loadinfo_s *loadinfo)
       return -ENOMEM;
     }
 
-  /* Find the index to the section named ".ctors" */
+  /* Find the index to the section named ".ctors."  NOTE:  On old ABI system,
+   * .ctors is the name of the section containing the list of constructors;
+   * On newer systems, the similar section is called .init_array.  It is 
+   * expected that the linker script will force the sectino name to be ".ctors"
+   * in either case.
+   */
 
-  ctoridx = elf_findctors(loadinfo);
+  ctoridx = elf_findsection(loadinfo, ".ctors");
   if (ctoridx < 0)
     {
       /* This may not be a failure.  -ENOENT indicates that the file has no
        * static constructor section.
        */
 
-      bvdbg("elf_findctors failed: %d\n", ctoridx);
+      bvdbg("elf_findsection .ctors section failed: %d\n", ctoridx);
       return ret == -ENOENT ? OK : ret;
     }
 
@@ -286,7 +131,9 @@ int elf_loadctors(FAR struct elf_loadinfo_s *loadinfo)
 
   shdr = &loadinfo->shdr[ctoridx];
 
-  /* Allocate memory to hold a copy of the .ctor section */
+  /* Get the size of the .ctor section and the number of constructors that
+   * will need to be called.
+   */
 
   ctorsize         = shdr->sh_size;
   loadinfo->nctors = ctorsize / sizeof(elf_ctor_t);
@@ -302,71 +149,72 @@ int elf_loadctors(FAR struct elf_loadinfo_s *loadinfo)
     {
       /* Check an assumption that we made above */
 
-      DEBUGASSERT(shdr->sh_entsize == sizeof(elf_ctor_t));
-
-      loadinfo->ctors  = (elf_ctor_t)kmalloc(ctorsize);
-      if (!loadinfo->ctors)
-        {
-          bdbg("Failed to allocate memory for .ctors\n");
-          return -ENOMEM;
-        }
+      DEBUGASSERT(shdr->sh_size == loadinfo->nctors * sizeof(elf_ctor_t));
 
-      /* Read the section header table into memory */
+      /* In the old ABI, the .ctors section is not allocated.  In that case,
+       * we need to allocate memory to hold the .ctors and then copy the
+       * from the file into the allocated memory.
+       *
+       * SHF_ALLOC indicates that the section requires memory during
+       * execution.
+       */
 
-      ret = elf_read(loadinfo, (FAR uint8_t*)loadinfo->ctors, ctorsize,
-                     shdr->sh_offset);
-      if (ret < 0)
+      if ((shdr->sh_flags & SHF_ALLOC) == 0)
         {
-          bdbg("Failed to allocate .ctors: %d\n", ret);
-        }
+          /* Not loaded -> Old ABI. */
 
-      /* Fix up all of the .ctor addresses */
+          loadinfo->newabi = false;
 
-      for (i = 0; i < loadinfo->nctors; i++)
-        {
-          FAR uintptr_t *ptr = (uintptr_t *)((FAR void *)(&loadinfo->ctors)[i]);
+          /* Allocate memory to hold a copy of the .ctor section */
 
-          bvdbg("ctor %d: %08lx + %08lx = %08lx\n", i,
-                *ptr, loadinfo->alloc, *ptr + loadinfo->alloc);
+          loadinfo->ctors  = (elf_ctor_t*)kmalloc(ctorsize);
+          if (!loadinfo->ctors)
+            {
+              bdbg("Failed to allocate memory for .ctors\n");
+              return -ENOMEM;
+            }
 
-          *ptr += loadinfo->alloc;
-        }
-    }
+          /* Read the section header table into memory */
 
-  return OK;
-}
+          ret = elf_read(loadinfo, (FAR uint8_t*)loadinfo->ctors, ctorsize,
+                         shdr->sh_offset);
+          if (ret < 0)
+            {
+              bdbg("Failed to allocate .ctors: %d\n", ret);
+              return ret;
+            }
 
-/****************************************************************************
- * Name: elf_doctors
- *
- * Description:
- *   Execute C++ static constructors.
- *
- * Input Parameters:
- *   loadinfo - Load state information
- *
- * Returned Value:
- *   0 (OK) is returned on success and a negated errno is returned on
- *   failure.
- *
- ****************************************************************************/
+          /* Fix up all of the .ctor addresses.  Since the addresses
+           * do not lie in allocated memory, there will be no relocation
+           * section for them.
+           */
 
-int elf_doctors(FAR struct elf_loadinfo_s *loadinfo)
-{
-  elf_ctor_t ctor = (elf_ctor_t)loadinfo->ctors;
-  int i;
+          for (i = 0; i < loadinfo->nctors; i++)
+            {
+              FAR uintptr_t *ptr = (uintptr_t *)((FAR void *)(&loadinfo->ctors)[i]);
 
-  /* Execute each constructor */
+              bvdbg("ctor %d: %08lx + %08lx = %08lx\n",
+                    i, *ptr, loadinfo->alloc, *ptr + loadinfo->alloc);
 
-  for (i = 0; i < loadinfo->nctors; i++)
-    {
-      bvdbg("Calling ctor %d at %p\n", i, (FAR void *)ctor);
+              *ptr += loadinfo->alloc;
+            }
+        }
+      else
+        {
+          /* Loaded -> New ABI. */
 
-      ctor();
-      ctor++;
+          loadinfo->newabi = true;
+
+          /* Save the address of the .ctors (actually, .init_array) where it was
+           * loaded into memory.  Since the .ctors lie in allocated memory, they
+           * will be relocated via the normal mechanism.
+           */
+ 
+          loadinfo->ctors = (elf_ctor_t*)shdr->sh_addr;
+        }
     }
 
   return OK;
 }
 
-#endif /* CONFIG_ELF_CONSTRUCTORS */
+#endif /* CONFIG_BINFMT_CONSTRUCTORS */
diff --git a/nuttx/binfmt/libelf/libelf_load.c b/nuttx/binfmt/libelf/libelf_load.c
index 505e2c813..221ae8d43 100644
--- a/nuttx/binfmt/libelf/libelf_load.c
+++ b/nuttx/binfmt/libelf/libelf_load.c
@@ -76,62 +76,6 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: elf_loadshdrs
- *
- * Description:
- *   Loads section headers into memory.
- *
- * Returned Value:
- *   0 (OK) is returned on success and a negated errno is returned on
- *   failure.
- *
- ****************************************************************************/
-
-static inline int elf_loadshdrs(FAR struct elf_loadinfo_s *loadinfo)
-{
-  size_t shdrsize;
-  int ret;
-
-  DEBUGASSERT(loadinfo->shdr == NULL);
-
-  /* Verify that there are sections */
-
-  if (loadinfo->ehdr.e_shnum < 1)
-    {
-      bdbg("No sections(?)\n");
-      return -EINVAL;
-    }
-
-  /* Get the total size of the section header table */
-
-  shdrsize = (size_t)loadinfo->ehdr.e_shentsize * (size_t)loadinfo->ehdr.e_shnum;
-  if(loadinfo->ehdr.e_shoff + shdrsize > loadinfo->filelen)
-    {
-      bdbg("Insufficent space in file for section header table\n");
-      return -ESPIPE;
-    }
-
-  /* Allocate memory to hold a working copy of the sector header table */
-
-  loadinfo->shdr = (FAR Elf32_Shdr*)kmalloc(shdrsize);
-  if (!loadinfo->shdr)
-    {
-      bdbg("Failed to allocate the section header table. Size: %ld\n", (long)shdrsize);
-      return -ENOMEM;
-    }
-
-  /* Read the section header table into memory */
-
-  ret = elf_read(loadinfo, (FAR uint8_t*)loadinfo->shdr, shdrsize, loadinfo->ehdr.e_shoff);
-  if (ret < 0)
-    {
-      bdbg("Failed to read section header table: %d\n", ret);
-    }
-
-  return ret;
-}
-
-/****************************************************************************
  * Name: elf_allocsize
  *
  * Description:
@@ -292,7 +236,7 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 
   /* Find static constructors. */
 
-#ifdef CONFIG_ELF_CONSTRUCTORS
+#ifdef CONFIG_BINFMT_CONSTRUCTORS
   ret = elf_loadctors(loadinfo);
   if (ret < 0)
     {
diff --git a/nuttx/binfmt/libelf/libelf_sections.c b/nuttx/binfmt/libelf/libelf_sections.c
new file mode 100644
index 000000000..c41793544
--- /dev/null
+++ b/nuttx/binfmt/libelf/libelf_sections.c
@@ -0,0 +1,284 @@
+/****************************************************************************
+ * binfmt/libelf/libelf_sections.c
+ *
+ *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/binfmt/elf.h>
+
+#include "libelf.h"
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Constant Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: elf_sectname
+ *
+ * Description:
+ *   Get the symbol name in loadinfo->iobuffer[].
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
+ ****************************************************************************/
+
+static inline int elf_sectname(FAR struct elf_loadinfo_s *loadinfo,
+                               FAR const Elf32_Shdr *shdr)
+{
+  FAR Elf32_Shdr *shstr;
+  FAR uint8_t *buffer;
+  off_t  offset;
+  size_t readlen;
+  size_t bytesread;
+  int shstrndx;
+  int ret;
+
+  /* Get the section header table index of the entry associated with the
+   * section name string table. If the file has no section name string table,
+   * this member holds the value SH_UNDEF.
+   */
+
+  shstrndx = loadinfo->ehdr.e_shstrndx;
+  if (shstrndx == SHN_UNDEF)
+    {
+      bdbg("No section header string table\n");
+      return -EINVAL;
+    }
+
+  /* Get the section name string table section header */
+
+  shstr = &loadinfo->shdr[shstrndx];
+
+  /* Get the file offset to the string that is the name of the section. This
+   * is the sum of:
+   *
+   *   shstr->sh_offset: The file offset to the first byte of the section
+   *     header string table data.
+   *   shdr->sh_name: The offset to the name of the section in the section
+   *     name table
+   */
+
+  offset = shstr->sh_offset + shdr->sh_name;
+
+  /* Loop until we get the entire section name into memory */
+
+  buffer    = loadinfo->iobuffer;
+  bytesread = 0;
+
+  for (;;)
+    {
+      /* Get the number of bytes to read */
+
+      readlen = loadinfo->buflen - bytesread;
+      if (offset + readlen > loadinfo->filelen)
+        {
+          readlen = loadinfo->filelen - offset;
+          if (readlen <= 0)
+            {
+              bdbg("At end of file\n");
+              return -EINVAL;
+            }
+        }
+
+      /* Read that number of bytes into the array */
+
+      buffer = &loadinfo->iobuffer[bytesread];
+      ret = elf_read(loadinfo, buffer, readlen, offset);
+      if (ret < 0)
+        {
+          bdbg("Failed to read section name\n");
+          return ret;
+        }
+
+      bytesread += readlen;
+
+      /* Did we read the NUL terminator? */
+
+      if (memchr(buffer, '\0', readlen) != NULL)
+        {
+          /* Yes, the buffer contains a NUL terminator. */
+
+          return OK;
+        }
+
+      /* No.. then we have to read more */
+
+      ret = elf_reallocbuffer(loadinfo, CONFIG_ELF_BUFFERINCR);
+      if (ret < 0)
+        {
+          bdbg("elf_reallocbuffer failed: %d\n", ret);
+          return ret;
+        }
+    }
+
+  /* We will not get here */
+
+  return OK;
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: elf_loadshdrs
+ *
+ * Description:
+ *   Loads section headers into memory.
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
+ ****************************************************************************/
+
+int elf_loadshdrs(FAR struct elf_loadinfo_s *loadinfo)
+{
+  size_t shdrsize;
+  int ret;
+
+  DEBUGASSERT(loadinfo->shdr == NULL);
+
+  /* Verify that there are sections */
+
+  if (loadinfo->ehdr.e_shnum < 1)
+    {
+      bdbg("No sections(?)\n");
+      return -EINVAL;
+    }
+
+  /* Get the total size of the section header table */
+
+  shdrsize = (size_t)loadinfo->ehdr.e_shentsize * (size_t)loadinfo->ehdr.e_shnum;
+  if(loadinfo->ehdr.e_shoff + shdrsize > loadinfo->filelen)
+    {
+      bdbg("Insufficent space in file for section header table\n");
+      return -ESPIPE;
+    }
+
+  /* Allocate memory to hold a working copy of the sector header table */
+
+  loadinfo->shdr = (FAR Elf32_Shdr*)kmalloc(shdrsize);
+  if (!loadinfo->shdr)
+    {
+      bdbg("Failed to allocate the section header table. Size: %ld\n", (long)shdrsize);
+      return -ENOMEM;
+    }
+
+  /* Read the section header table into memory */
+
+  ret = elf_read(loadinfo, (FAR uint8_t*)loadinfo->shdr, shdrsize, loadinfo->ehdr.e_shoff);
+  if (ret < 0)
+    {
+      bdbg("Failed to read section header table: %d\n", ret);
+    }
+
+  return ret;
+}
+
+/****************************************************************************
+ * Name: elf_findsection
+ *
+ * Description:
+ *   A section by its name.
+ *
+ * Input Parameters:
+ *   loadinfo - Load state information
+ *   sectname - Name of the section to find
+ *
+ * Returned Value:
+ *   On success, the index to the section is returned; A negated errno value
+ *   is returned on failure.
+ *
+ ****************************************************************************/
+
+int elf_findsection(FAR struct elf_loadinfo_s *loadinfo,
+                    FAR const char *sectname)
+{
+  FAR const Elf32_Shdr *shdr;
+  int ret;
+  int i;
+
+  /* Search through the shdr[] array in loadinfo for a section named 'sectname' */
+
+  for (i = 0; i < loadinfo->ehdr.e_shnum; i++)
+    {
+      /* Get the name of this section */
+
+      shdr = &loadinfo->shdr[i];
+      ret  = elf_sectname(loadinfo, shdr);
+      if (ret < 0)
+        {
+          bdbg("elf_sectname failed: %d\n", ret);
+          return ret;
+        }
+ 
+      /* Check if the name of this section is 'sectname' */
+
+      bvdbg("%d. Comparing \"%s\" and .\"%s\"\n",
+            i, loadinfo->iobuffer, sectname);
+
+      if (strcmp((FAR const char *)loadinfo->iobuffer, sectname) == 0)
+        {
+          /* We found it... return the index */
+
+          return i;
+        }
+    }
+
+  /* We failed to find a section with this name. */
+
+  return -ENOENT;
+}
diff --git a/nuttx/binfmt/libelf/libelf_uninit.c b/nuttx/binfmt/libelf/libelf_uninit.c
index 06bb89681..3ec6f6c61 100644
--- a/nuttx/binfmt/libelf/libelf_uninit.c
+++ b/nuttx/binfmt/libelf/libelf_uninit.c
@@ -115,15 +115,6 @@ int elf_freebuffers(struct elf_loadinfo_s *loadinfo)
       loadinfo->shdr      = NULL;
     }
 
-#ifdef CONFIG_ELF_CONSTRUCTORS
-  if (loadinfo->ctors)
-    {
-      kfree((FAR void *)loadinfo->ctors);
-      loadinfo->ctors     = NULL;
-      loadinfo->nctors    = 0;
-    }
-#endif
-
   if (loadinfo->iobuffer)
     {
       kfree((FAR void *)loadinfo->iobuffer);
diff --git a/nuttx/binfmt/libelf/libelf_unload.c b/nuttx/binfmt/libelf/libelf_unload.c
index d7a882711..8102f7bf2 100644
--- a/nuttx/binfmt/libelf/libelf_unload.c
+++ b/nuttx/binfmt/libelf/libelf_unload.c
@@ -91,6 +91,26 @@ int elf_unload(struct elf_loadinfo_s *loadinfo)
       loadinfo->allocsize = 0;
     }
 
+  /* Release any allocated constructor memory */
+
+#ifdef CONFIG_BINFMT_CONSTRUCTORS
+  if (loadinfo->ctors)
+    {
+      /* In the old ABI, the .ctors section is not make for allocation.  In
+       * that case, we need to free the working buffer that was used to hold
+       * the constructors.
+       */
+
+      if (!loadinfo->newabi)
+        {
+          kfree((FAR void *)loadinfo->ctors);
+        }
+
+      loadinfo->ctors     = NULL;
+      loadinfo->nctors    = 0;
+    }
+#endif
+
   return OK;
 }