text: /****************************************************************************
   * binfmt/libelf/libelf_read.c
   *
   *   Copyright (C) 2014 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 <sys/types.h>
  #include <stdint.h>
  #include <unistd.h>
  #include <string.h>
  #include <elf32.h>
  #include <debug.h>
  #include <errno.h>
  
  #include <nuttx/binfmt/elf.h>
  
  /****************************************************************************
   * Pre-processor Definitions
   ****************************************************************************/
  
  #undef ELF_DUMP_READDATA       /* Define to dump all file data read */
  
  /****************************************************************************
   * Private Constant Data
   ****************************************************************************/
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: elf_dumpreaddata
   ****************************************************************************/
  
  #if defined(ELF_DUMP_READDATA)
  static inline void elf_dumpreaddata(FAR char *buffer, int buflen)
  {
    FAR uint32_t *buf32 = (FAR uint32_t *)buffer;
    int i;
    int j;
  
    for (i = 0; i < buflen; i += 32)
      {
        syslog(LOG_DEBUG, "%04x:", i);
        for (j = 0; j < 32; j += sizeof(uint32_t))
          {
            syslog(LOG_DEBUG, "  %08x", *buf32++);
          }
  
        syslog(LOG_DEBUG, "\n");
      }
  }
  #else
  #  define elf_dumpreaddata(b,n)
  #endif
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: elf_read
   *
   * Description:
   *   Read 'readsize' bytes from the object file at 'offset'.  The data is
   *   read into 'buffer.' If 'buffer' is part of the ELF address environment,
   *   then the caller is responsibile for assuring that that address
   *   environment is in place before calling this function (i.e., that
   *   elf_addrenv_select() has been called if CONFIG_ARCH_ADDRENV=y).
   *
   * Returned Value:
   *   0 (OK) is returned on success and a negated errno is returned on
   *   failure.
   *
   ****************************************************************************/
  
  int elf_read(FAR struct elf_loadinfo_s *loadinfo, FAR uint8_t *buffer,
               size_t readsize, off_t offset)
  {
    ssize_t nbytes;      /* Number of bytes read */
    off_t   rpos;        /* Position returned by lseek */
  
    binfo("Read %ld bytes from offset %ld\n", (long)readsize, (long)offset);
  
    /* Loop until all of the requested data has been read. */
  
    while (readsize > 0)
      {
        /* Seek to the next read position */
  
        rpos = lseek(loadinfo->filfd, offset, SEEK_SET);
        if (rpos != offset)
          {
            int errval = errno;
            berr("Failed to seek to position %lu: %d\n",
                 (unsigned long)offset, errval);
            return -errval;
          }
  
        /* Read the file data at offset into the user buffer */
  
         nbytes = read(loadinfo->filfd, buffer, readsize);
         if (nbytes < 0)
           {
             int errval = errno;
  
             /* EINTR just means that we received a signal */
  
             if (errval != EINTR)
               {
                 berr("Read from offset %lu failed: %d\n",
                      (unsigned long)offset, errval);
                 return -errval;
               }
           }
         else if (nbytes == 0)
           {
             berr("Unexpected end of file\n");
             return -ENODATA;
           }
         else
           {
             readsize -= nbytes;
             buffer   += nbytes;
             offset   += nbytes;
           }
      }
  
    elf_dumpreaddata(buffer, readsize);
    return OK;
  }
  