Finishes basic coding of ELF file support

git-svn-id: http://svn.code.sf.net/p/nuttx/code/trunk@5259 42af7a65-404d-4744-a932-0658087f49c3

nuttx/binfmt/libelf/Kconfig

@@ -15,6 +15,23 @@ config ELF_STACKSIZE
 	---help---
 		This is the default stack size that will will be used when starting ELF binaries.
 
+config ELF_BUFFERSIZE
+	int "ELF I/O Buffer Size"
+	default 128
+	---help---
+		This is an I/O buffer that is used to access the ELF file.  Variable length items
+		will need to be read (such as symbol names).  This is really just this initial
+		size of the buffer; it will be reallocated as necessary to hold large symbol
+		names).  Default: 128
+
+config ELF_BUFFERINCR
+	int "ELF I/O Buffer Realloc Increment"
+	default 32
+	---help---
+		This is an I/O buffer that is used to access the ELF file.  Variable length items
+		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

nuttx/binfmt/libelf/Make.defs

@@ -45,6 +45,10 @@ 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
 
+ifeq ($(CONFIG_ELF_CONSTRUCTORS),y)
+BINFMT_CSRCS += libelf_ctors.c
+endif
+
 # Hook the libelf subdirectory into the build
 
 VPATH += libelf

nuttx/binfmt/libelf/libelf.h

@@ -105,9 +105,78 @@ int elf_findsymtab(FAR struct elf_loadinfo_s *loadinfo);
  * Description:
  *   Read the ELFT symbol structure at the specfied index into memory.
  *
+ * Input Parameters:
+ *   loadinfo - Load state information
+ *   index    - Symbol table index
+ *   sym      - Location to return the table entry
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
  ****************************************************************************/
 
 int elf_readsym(FAR struct elf_loadinfo_s *loadinfo, int index,
                 FAR Elf32_Sym *sym);
 
+/****************************************************************************
+ * Name: elf_symvalue
+ *
+ * Description:
+ *   Get the value of a symbol.  The updated value of the symbol is returned
+ *   in the st_value field of the symbol table entry.
+ *
+ * Input Parameters:
+ *   loadinfo - Load state information
+ *   sym      - Symbol table entry (value might be undefined)
+ *   exports  - The symbol table to use for resolving undefined symbols.
+ *   nexports - Number of symbols in the symbol table.
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
+ ****************************************************************************/
+
+int elf_symvalue(FAR struct elf_loadinfo_s *loadinfo, FAR Elf32_Sym *sym,
+                 FAR const struct symtab_s *exports, int nexports);
+
+/****************************************************************************
+ * Name: elf_findctors
+ *
+ * Description:
+ *   Find 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_findctors(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 */

nuttx/binfmt/libelf/libelf_bind.c

@@ -46,6 +46,7 @@
 #include <assert.h>
 #include <debug.h>
 
+#include <nuttx/kmalloc.h>
 #include <nuttx/binfmt/elf.h>
 #include <nuttx/binfmt/symtab.h>
 
@@ -63,6 +64,10 @@
 #  undef CONFIG_ELF_DUMPBUFFER
 #endif
 
+#ifndef CONFIG_ELF_BUFFERSIZE
+#  define CONFIG_ELF_BUFFERSIZE 128
+#endif
+
 #ifdef CONFIG_ELF_DUMPBUFFER
 # define elf_dumpbuffer(m,b,n) bvdbgdumpbuffer(m,b,n)
 #else
@@ -124,7 +129,9 @@ static inline int elf_readrel(FAR struct elf_loadinfo_s *loadinfo,
  *
  ****************************************************************************/
 
-static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx)
+static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx,
+                        FAR const struct symtab_s *exports, int nexports)
+
 {
   FAR Elf32_Shdr *relsec = &loadinfo->shdr[relidx];
   FAR Elf32_Shdr *dstsec = &loadinfo->shdr[relsec->sh_info];
@@ -165,6 +172,16 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx)
           return ret;
         }
 
+      /* Get the value of the symbol (in sym.st_value) */
+
+      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;
+        }
+
       /* Calculate the relocation address */
 
       if (rel.r_offset < 0 || rel.r_offset > dstsec->sh_size - sizeof(uint32_t))
@@ -189,7 +206,8 @@ static int elf_relocate(FAR struct elf_loadinfo_s *loadinfo, int relidx)
   return OK;
 }
 
-static int elf_relocateadd(FAR struct elf_loadinfo_s *loadinfo, int relidx)
+static int elf_relocateadd(FAR struct elf_loadinfo_s *loadinfo, int relidx,
+                           FAR const struct symtab_s *exports, int nexports)
 {
   bdbg("Not implemented\n");
   return -ENOSYS;
@@ -226,6 +244,18 @@ int elf_bind(FAR struct elf_loadinfo_s *loadinfo,
       return ret;
     }
 
+  /* Allocate an I/O buffer.  This buffer is used only by elf_symname() to
+   * accumulate the variable length symbol name.
+   */
+
+  loadinfo->iobuffer = (FAR uint8_t *)kmalloc(CONFIG_ELF_BUFFERSIZE);
+  if (!loadinfo->iobuffer)
+    {
+      bdbg("Failed to allocate an I/O buffer\n");
+      return -ENOMEM;
+    }
+  loadinfo->buflen = CONFIG_ELF_BUFFERSIZE;
+
   /* Process relocations in every allocated section */
 
   for (i = 1; i < loadinfo->ehdr.e_shnum; i++)
@@ -251,11 +281,11 @@ int elf_bind(FAR struct elf_loadinfo_s *loadinfo,
 
       if (loadinfo->shdr[i].sh_type == SHT_REL)
         {
-          ret = elf_relocate(loadinfo, i);
+          ret = elf_relocate(loadinfo, i, exports, nexports);
         }
       else if (loadinfo->shdr[i].sh_type == SHT_RELA)
         {
-          ret = elf_relocateadd(loadinfo, i);
+          ret = elf_relocateadd(loadinfo, i, exports, nexports);
         }
 
       if (ret < 0)
@@ -269,6 +299,12 @@ int elf_bind(FAR struct elf_loadinfo_s *loadinfo,
 #ifdef CONFIG_ELF_ICACHE
   arch_flushicache((FAR void*)loadinfo->alloc, loadinfo->allocsize);
 #endif
+
+  /* Free the I/O buffer */
+
+  kfree(loadinfo->iobuffer);
+  loadinfo->iobuffer = NULL;
+  loadinfo->buflen   = 0;
   return ret;
 }
 

nuttx/binfmt/libelf/libelf_ctors.c

@@ -0,0 +1,134 @@
+/****************************************************************************
+ * binfmt/libelf/libelf_ctors.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 <debug.h>
+
+#include <nuttx/binfmt/elf.h>
+
+#include "libelf"
+
+#ifdef CONFIG_ELF_CONSTRUCTORS
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+typedef FAR void (*ctor_t)(void);
+
+/****************************************************************************
+ * Private Constant Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: elf_findctors
+ *
+ * Description:
+ *   Find 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.
+ *
+ ****************************************************************************/
+
+int elf_findctors(FAR struct elf_loadinfo_s *loadinfo)
+{
+  /* Search through the shdr[] array in loadinfo for a section named .ctors */
+#warning "Missing logic"
+
+  /* Get the address of the beginning of the constructros from the sh_addr
+   * field of the section.  Save that in the ctors field of the loadinfo
+   * structure.
+   */
+#warning "Missing logic"
+
+  /* Get the number of constructors from the sh_size field of the section.
+   * Save that number in the nctors field of the loadinfo structure.
+   */ 
+#warning "Missing logic"
+  return -ENOSYS;
+}
+
+/****************************************************************************
+ * 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.
+ *
+ ****************************************************************************/
+
+int elf_doctors(FAR struct elf_loadinfo_s *loadinfo)
+{
+  ctor_t ctor = (ctor_t)loadinfo->ctors;
+  int i;
+
+  /* Execute each constructor */
+
+  for (i = 0; i < loadinfo->nctors; i++)
+    {
+      ctor();
+      ctor++;
+    }
+}
+
+#endif /* CONFIG_ELF_CONSTRUCTORS

nuttx/binfmt/libelf/libelf_load.c

@@ -327,6 +327,7 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
 
   ret = elf_filelen(loadinfo);
     {
+      bdbg("elf_filelen failed: %d\n", ret);
       return ret;
     }
 
@@ -335,6 +336,7 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
   ret = elf_loadshdrs(loadinfo);
   if (ret < 0)
     {
+      bdbg("elf_loadshdrs failed: %d\n", ret);
       return ret;
     }
 
@@ -347,11 +349,19 @@ int elf_load(FAR struct elf_loadinfo_s *loadinfo)
   ret = elf_loadfile(loadinfo);
   if (ret < 0)
     {
+      bdbg("elf_loadfile failed: %d\n", ret);
       goto errout_with_shdrs;
     }
 
   /* Find static constructors. */
-#warning "Missing logic"
+
+#ifdef CONFIG_ELF_CONSTRUCTORS
+  ret = elf_findctors(loadinfo);
+    {
+      bdbg("elf_findctors failed: %d\n", ret);
+      goto errout_with_shdrs;
+    }
+#endif
 
   return OK;
 

nuttx/binfmt/libelf/libelf_symbols.c

@@ -39,11 +39,14 @@
 
 #include <nuttx/config.h>
 
+#include <stdlib.h>
+#include <string.h>
 #include <elf.h>
-#include <debug.h>
 #include <errno.h>
+#include <debug.h>
 
 #include <nuttx/binfmt/elf.h>
+#include <nuttx/binfmt/symtab.h>
 
 #include "libelf.h"
 
@@ -51,6 +54,10 @@
  * Pre-Processor Definitions
  ****************************************************************************/
 
+#ifndef CONFIG_ELF_BUFFERINCR
+#  define CONFIG_ELF_BUFFERINCR 32
+#endif
+
 /****************************************************************************
  * Private Constant Data
  ****************************************************************************/
@@ -59,6 +66,101 @@
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: elf_symname
+ *
+ * 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 int elf_symname(FAR struct elf_loadinfo_s *loadinfo,
+                       FAR const Elf32_Sym *sym)
+{
+  FAR uint8_t *buffer;
+  off_t  offset;
+  size_t readlen;
+  size_t bytesread;
+  int ret;
+
+  /* Get the file offset to the string that is the name of the symbol.  The
+   * st_name member holds an offset into the file's symbol string table.
+   */
+
+  if (sym->st_name == 0)
+    {
+      bdbg("Symbol has no name\n");
+      return -ENOENT;
+    }
+
+  offset = loadinfo->shdr[loadinfo->strtabidx].sh_offset + sym->st_name;
+
+  /* Loop until we get the entire symbol 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 symbol 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 */
+
+      buffer = realloc((FAR void *)loadinfo->iobuffer,
+                       loadinfo->buflen + CONFIG_ELF_BUFFERINCR);
+      if (!buffer)
+        {
+          bdbg("Failed to reallocate the I/O buffer\n");
+          return -ENOMEM;
+        }
+
+      /* Save the new buffer info */
+
+      loadinfo->iobuffer = buffer;
+      loadinfo->buflen   += CONFIG_ELF_BUFFERINCR;
+    }
+
+  /* We will not get here */
+
+  return OK;
+}
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -108,6 +210,15 @@ int elf_findsymtab(FAR struct elf_loadinfo_s *loadinfo)
  * Description:
  *   Read the ELFT symbol structure at the specfied index into memory.
  *
+ * Input Parameters:
+ *   loadinfo - Load state information
+ *   index    - Symbol table index
+ *   sym      - Location to return the table entry
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
  ****************************************************************************/
 
 int elf_readsym(FAR struct elf_loadinfo_s *loadinfo, int index,
@@ -132,3 +243,94 @@ int elf_readsym(FAR struct elf_loadinfo_s *loadinfo, int index,
 
   return elf_read(loadinfo, (FAR uint8_t*)sym, sizeof(Elf32_Sym), offset);
 }
+
+/****************************************************************************
+ * Name: elf_symvalue
+ *
+ * Description:
+ *   Get the value of a symbol.  The updated value of the symbol is returned
+ *   in the st_value field of the symbol table entry.
+ *
+ * Input Parameters:
+ *   loadinfo - Load state information
+ *   sym      - Symbol table entry (value might be undefined)
+ *
+ * Returned Value:
+ *   0 (OK) is returned on success and a negated errno is returned on
+ *   failure.
+ *
+ ****************************************************************************/
+
+int elf_symvalue(FAR struct elf_loadinfo_s *loadinfo, FAR Elf32_Sym *sym,
+                 FAR const struct symtab_s *exports, int nexports)
+{
+  FAR const struct symtab_s *symbol;
+  uintptr_t secbase;
+  int ret;
+
+  switch (sym->st_shndx)
+    {
+    case SHN_COMMON:
+      {
+        /* NuttX ELF modules should be compiled with -fno-common. */
+
+        bdbg("SHN_COMMON: Re-compile with -fno-common\n");
+        return -EINVAL;
+      }
+
+    case SHN_ABS:
+      {
+        /* st_value already holds the correct value */
+
+        bvdbg("SHN_ABS: st_value=%08lx\n", (long)sym->st_value);
+        return OK;
+      }
+
+    case SHN_UNDEF:
+      {
+        /* Get the name of the undefined symbol */
+
+        ret = elf_symname(loadinfo, sym);
+        if (ret < 0)
+          {
+            bdbg("SHN_UNDEF: Failed to get symbol name: %d\n", ret);
+            return ret;
+          }
+
+        /* Check if the base code exports a symbol of this name */
+
+#ifdef CONFIG_SYMTAB_ORDEREDBYNAME
+        symbol = symtab_findorderedbyname(exports, (FAR char *)loadinfo->iobuffer, nexports);
+#else
+        symbol = symtab_findbyname(exports, (FAR char *)loadinfo->iobuffer, nexports);
+#endif
+        if (!symbol)
+          {
+            bdbg("SHN_UNDEF: Exported symbol \"%s\" not found\n", loadinfo->iobuffer);
+            return -ENOENT;
+          }
+
+        /* Yes... add the exported symbol value to the ELF symbol table entry */
+
+        bvdbg("SHN_ABS: name=%s %08x+%08x=%08x\n",
+              loadinfo->iobuffer, sym->st_value, symbol->sym_value,
+              sym->st_value + symbol->sym_value);
+
+        sym->st_value += (Elf32_Word)((uintptr_t)symbol->sym_value);
+      }
+      break;
+
+    default:
+      {
+        secbase = loadinfo->shdr[sym->st_shndx].sh_addr;
+
+        bvdbg("Other: %08x+%08x=%08x\n",
+              sym->st_value, secbase, sym->st_value + secbase);
+
+        sym->st_value += secbase;
+      }
+      break;
+    }
+
+  return OK;
+}

nuttx/binfmt/libelf/libelf_unload.c

@@ -80,17 +80,24 @@ int elf_unload(struct elf_loadinfo_s *loadinfo)
 
   if (loadinfo->alloc)
     {
-      kfree((void*)loadinfo->alloc);
+      kfree((FAR void *)loadinfo->alloc);
       loadinfo->alloc     = 0;
       loadinfo->allocsize = 0;
     }
 
   if (loadinfo->shdr)
     {
-      kfree((void*)loadinfo->shdr);
+      kfree((FAR void *)loadinfo->shdr);
       loadinfo->shdr      = NULL;
     }
 
+  if (loadinfo->iobuffer)
+    {
+      kfree((FAR void *)loadinfo->iobuffer);
+      loadinfo->iobuffer  = NULL;
+      loadinfo->buflen    = 0;
+    }
+
   return OK;
 }
 

nuttx/include/nuttx/binfmt/elf.h

@@ -69,14 +69,17 @@ struct elf_loadinfo_s
   uintptr_t       alloc;       /* Allocated memory with the ELF file is loaded */
   size_t          allocsize;   /* Size of the memory allocation */
   off_t           filelen;     /* Length of the entire ELF file */
+  int             filfd;       /* Descriptor for the file being loaded */
 #ifdef CONFIG_ELF_CONSTRUCTORS
-  uintptr_t       ctors;       /* Static constructors */
+  uintptr_t       ctors;       /* Location of static constructors in memory */
+  uint16_t        nctors;      /* Number of constructors */
 #endif
-  int             filfd;       /* Descriptor for the file being loaded */
   uint16_t        symtabidx;   /* Symbol table section index */
   uint16_t        strtabidx;   /* String table section index */
+  uint16_t        buflen;      /* size of iobuffer[] */
   Elf32_Ehdr      ehdr;        /* Buffered ELF file header */
   FAR Elf32_Shdr *shdr;        /* Buffered ELF section headers */
+  uint8_t        *iobuffer;    /* File I/O buffer */
 };
 
 /****************************************************************************