bfd_follow_gnu_debuglink: New function. Follow the pointer contained inside a

.gnu_debuglink section.

1 files changed, 334 insertions, 1 deletions

diff --git a/bfd/opncls.c b/bfd/opncls.c
index c244388..81bd2c8 100644
--- a/bfd/opncls.c
+++ b/bfd/opncls.c
@@ -1,6 +1,6 @@
 /* opncls.c -- open and close a BFD.
    Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2000,
-   2001, 2002
+   2001, 2002, 2003
    Free Software Foundation, Inc.
 
    Written by Cygnus Support.
@@ -25,6 +25,7 @@
 #include "sysdep.h"
 #include "objalloc.h"
 #include "libbfd.h"
+#include "libiberty.h"
 
 #ifndef S_IXUSR
 #define S_IXUSR 0100	/* Execute by owner.  */
@@ -699,3 +700,335 @@ bfd_release (abfd, block)
 {
   objalloc_free_block ((struct objalloc *) abfd->memory, block);
 }
+
+
+/* 
+   GNU Extension: separate debug-info files 
+   
+   The idea here is that a special section called .gnu_debuglink might be
+   embedded in a binary file, which indicates that some *other* file
+   contains the real debugging information. This special section contains a
+   filename and CRC32 checksum, which we read and resolve to another file,
+   if it exists.
+
+   This facilitates "optional" provision of debugging information, without
+   having to provide two complete copies of every binary object (with and
+   without debug symbols).
+*/
+
+static unsigned long  calc_crc32                  PARAMS ((unsigned long, const unsigned char *, size_t));
+static char *         get_debug_link_info         PARAMS ((bfd *, unsigned long *));
+static bfd_boolean    separate_debug_file_exists  PARAMS ((const char *, const unsigned long));
+static char *         find_separate_debug_file    PARAMS ((bfd *, const char *));
+
+/*
+INTERNAL_FUNCTION
+	calc_crc32
+
+SYNOPSIS
+	unsigned long calc_crc32 (unsigned long crc, const unsigned char *buf, size_t len);
+
+DESCRIPTION
+	Advance the CRC32 given by @var{crc} through @var{len}
+	bytes of @var{buf}. Return the updated CRC32 value.
+*/     
+
+static unsigned long
+calc_crc32 (crc, buf, len)
+     unsigned long crc;
+     const unsigned char *buf;
+     size_t len;
+{
+  static const unsigned long crc32_table[256] =
+    {
+      0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
+      0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
+      0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
+      0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+      0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
+      0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
+      0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
+      0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+      0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
+      0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
+      0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
+      0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+      0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
+      0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
+      0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
+      0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+      0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
+      0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+      0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
+      0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+      0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
+      0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
+      0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
+      0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+      0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
+      0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
+      0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
+      0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+      0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
+      0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+      0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
+      0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+      0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
+      0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
+      0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
+      0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+      0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
+      0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
+      0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
+      0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+      0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
+      0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+      0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
+      0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+      0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
+      0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
+      0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
+      0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+      0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
+      0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
+      0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
+      0x2d02ef8d
+    };
+  const unsigned char *end;
+
+  crc = ~crc & 0xffffffff;
+  for (end = buf + len; buf < end; ++ buf)
+    crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8);
+  return ~crc & 0xffffffff;;
+}
+
+
+/*
+INTERNAL_FUNCTION
+	get_debug_link_info
+
+SYNOPSIS
+	char *get_debug_link_info (bfd *abfd, unsigned long *crc32_out)
+
+DESCRIPTION
+	fetch the filename and CRC32 value for any separate debuginfo
+	associated with @var{abfd}. Return NULL if no such info found,
+	otherwise return filename and update @var{crc32_out}.
+*/
+
+static char *
+get_debug_link_info (abfd, crc32_out)
+     bfd *abfd;
+     unsigned long *crc32_out;
+{
+  asection * sect;
+  bfd_size_type debuglink_size;
+  unsigned long crc32;
+  char * contents;
+  int crc_offset;
+  bfd_boolean ret;
+
+  BFD_ASSERT (abfd);
+  BFD_ASSERT (crc32_out);
+
+  sect = bfd_get_section_by_name (abfd, ".gnu_debuglink");
+
+  if (sect == NULL)
+    return NULL;
+
+  debuglink_size = bfd_section_size (abfd, sect);  
+
+  contents = xmalloc (debuglink_size);
+  ret = bfd_get_section_contents (abfd, sect, contents,
+				  (file_ptr)0, debuglink_size);
+  if (! ret)
+    {
+      free (contents);
+      return NULL;
+    }
+
+  /* Crc value is stored after the filename, aligned up to 4 bytes.  */
+  crc_offset = strlen (contents) + 1;
+  crc_offset = (crc_offset + 3) & ~3;
+
+  crc32 = bfd_get_32 (abfd, (bfd_byte *) (contents + crc_offset));
+
+  *crc32_out = crc32;
+  return contents;
+}
+
+/*
+INTERNAL_FUNCTION
+	separate_debug_file_exists
+
+SYNOPSIS
+	bfd_boolean separate_debug_file_exists (char * name, unsigned long crc32)
+
+DESCRIPTION
+	Checks to see if @var{name} is a file and if its contents
+	match @var{crc32}.
+*/
+
+static bfd_boolean
+separate_debug_file_exists (name, crc)
+     const char *name;
+     const unsigned long crc;
+{
+  static char buffer [8 * 1024];
+  unsigned long file_crc = 0;
+  int fd;
+  int count;
+
+  BFD_ASSERT (name);
+
+  fd = open (name, O_RDONLY);
+  if (fd < 0)
+    return FALSE;
+
+  while ((count = read (fd, buffer, sizeof (buffer))) > 0)
+    file_crc = calc_crc32 (file_crc, buffer, count);
+
+  close (fd);
+
+  return crc == file_crc;
+}
+
+
+/*
+INTERNAL_FUNCTION
+	find_separate_debug_file
+
+SYNOPSIS
+	char * find_separate_debug_file (bfd *abfd)
+
+DESCRIPTION
+	Searches @var{abfd} for a reference to separate debugging
+	information, scans various locations in the filesystem, including
+	the file tree rooted at @var{debug_file_directory}, and returns a
+	filename of such debugging information if the file is found and has
+	matching CRC32.  Returns NULL if no reference to debugging file
+	exists, or file cannot be found.
+*/
+
+static char *
+find_separate_debug_file (abfd, debug_file_directory)
+     bfd *abfd;
+     const char *debug_file_directory;
+{
+  char *basename;
+  char *dir;
+  char *debugfile;
+  unsigned long crc32;
+  int i;
+
+  BFD_ASSERT (abfd);
+  if (debug_file_directory == NULL)
+    debug_file_directory = ".";
+
+  /* BFD may have been opened from a stream.  */
+  if (! abfd->filename)
+    return NULL;
+
+  basename = get_debug_link_info (abfd, & crc32);
+
+  if (basename == NULL || strlen (basename) < 1)
+    return NULL;
+
+  dir = xstrdup (abfd->filename);
+  BFD_ASSERT (strlen (dir) != 0);
+  
+  /* Strip off filename part.  */
+  for (i = strlen (dir) - 1; i >= 0; i--)
+    if (IS_DIR_SEPARATOR (dir[i]))
+      break;
+  
+  dir[i + 1] = '\0';
+  BFD_ASSERT (dir[i] == '/' || dir[0] == '\0')
+
+  debugfile = xmalloc (strlen (debug_file_directory) + 1
+		       + strlen (dir)
+		       + strlen (".debug/")
+		       + strlen (basename) 
+		       + 1);
+
+  /* First try in the same directory as the original file:  */
+  strcpy (debugfile, dir);
+  strcat (debugfile, basename);
+
+  if (separate_debug_file_exists (debugfile, crc32))
+    {
+      free (basename);
+      free (dir);
+      return debugfile;
+    }
+
+  /* Then try in a subdirectory called .debug.  */
+  strcpy (debugfile, dir);
+  strcat (debugfile, ".debug/");
+  strcat (debugfile, basename);
+
+  if (separate_debug_file_exists (debugfile, crc32))
+    {
+      free (basename);
+      free (dir);
+      return debugfile;
+    }
+
+  /* Then try in the global debugfile directory.  */
+  strcpy (debugfile, debug_file_directory);
+  i = strlen (debug_file_directory) - 1;
+  if (i > 0
+      && debug_file_directory[i] != '/'
+      && dir[0] != '/')
+    strcat (debugfile, "/");
+  strcat (debugfile, dir);
+  strcat (debugfile, basename);
+
+  if (separate_debug_file_exists (debugfile, crc32))
+    {
+      free (basename);
+      free (dir);
+      return debugfile;
+    }
+
+  free (debugfile);
+  free (basename);
+  free (dir);
+  return NULL;
+}
+
+
+/*
+FUNCTION
+	bfd_follow_gnu_debuglink
+
+SYNOPSIS
+	char * bfd_follow_gnu_debuglink(bfd *abfd, const char *dir);
+
+DESCRIPTION
+
+	Takes a BFD and searches it for a .gnu_debuglink section.  If this
+	section is found, examines the section for the name and checksum of
+	a '.debug' file containing auxiliary debugging
+	information. Searches filesystem for .debug file in some standard
+	locations, including the directory tree rooted at @var{dir}, and if
+	found returns the full filename. If @var{dir} is NULL, will search
+	default path configured into libbfd at build time.
+
+RETURNS
+	<<NULL>> on any errors or failure to locate the .debug file,
+	otherwise a pointer to a heap-allocated string containing the
+	filename. The caller is responsible for freeing this string.
+*/
+
+char *
+bfd_follow_gnu_debuglink (abfd, dir)
+     bfd *abfd;
+     const char * dir;
+{
+#if 0 /* Disabled until DEBUGDIR can be defined by configure.in  */
+  if (dir == NULL)
+    dir = DEBUGDIR;
+#endif
+  return find_separate_debug_file (abfd, dir);
+}