+
+
+/*
+ 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).
+*/
+
+#define GNU_DEBUGLINK ".gnu_debuglink"
+/*
+FUNCTION
+ bfd_calc_gnu_debuglink_crc32
+
+SYNOPSIS
+ unsigned long bfd_calc_gnu_debuglink_crc32
+ (unsigned long crc, const unsigned char *buf, bfd_size_type len);
+
+DESCRIPTION
+ Computes a CRC value as used in the .gnu_debuglink section.
+ Advances the previously computed @var{crc} value by computing
+ and adding in the crc32 for @var{len} bytes of @var{buf}.
+
+RETURNS
+ Return the updated CRC32 value.
+*/
+
+unsigned long
+bfd_calc_gnu_debuglink_crc32 (unsigned long crc,
+ const unsigned char *buf,
+ bfd_size_type 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 (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 = malloc (debuglink_size);
+ if (contents == NULL)
+ return NULL;
+
+ ret = bfd_get_section_contents (abfd, sect, contents, 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, 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 (const char *name, const unsigned long crc)
+{
+ static char buffer [8 * 1024];
+ unsigned long file_crc = 0;
+ int fd;
+ bfd_size_type count;
+
+ BFD_ASSERT (name);
+
+ fd = open (name, O_RDONLY);
+ if (fd < 0)
+ return FALSE;
+
+ while ((count = read (fd, buffer, sizeof (buffer))) > 0)
+ file_crc = bfd_calc_gnu_debuglink_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 (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)
+ return NULL;
+
+ if (strlen (basename) < 1)
+ {
+ free (basename);
+ return NULL;
+ }
+
+ dir = strdup (abfd->filename);
+ if (dir == NULL)
+ {
+ free (basename);
+ return NULL;
+ }
+ 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 = malloc (strlen (debug_file_directory) + 1
+ + strlen (dir)
+ + strlen (".debug/")
+ + strlen (basename)
+ + 1);
+ if (debugfile == NULL)
+ {
+ free (basename);
+ free (dir);
+ return NULL;
+ }
+
+ /* 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, it examines the section for the name and checksum
+ of a '.debug' file containing auxiliary debugging information. It
+ then searches the filesystem for this .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, it will search a default path configured into
+ libbfd at build time. [XXX this feature is not currently
+ implemented].
+
+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 (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);
+}
+
+/*
+FUNCTION
+ bfd_create_gnu_debuglink_section
+
+SYNOPSIS
+ struct bfd_section *bfd_create_gnu_debuglink_section
+ (bfd *abfd, const char *filename);
+
+DESCRIPTION
+
+ Takes a @var{BFD} and adds a .gnu_debuglink section to it. The section is sized
+ to be big enough to contain a link to the specified @var{filename}.
+
+RETURNS
+ A pointer to the new section is returned if all is ok. Otherwise <<NULL>> is
+ returned and bfd_error is set.
+*/
+
+asection *
+bfd_create_gnu_debuglink_section (bfd *abfd, const char *filename)
+{
+ asection *sect;
+ bfd_size_type debuglink_size;
+
+ if (abfd == NULL || filename == NULL)
+ {
+ bfd_set_error (bfd_error_invalid_operation);
+ return NULL;
+ }
+
+ /* Strip off any path components in filename. */
+ filename = lbasename (filename);
+
+ sect = bfd_get_section_by_name (abfd, GNU_DEBUGLINK);
+ if (sect)
+ {
+ /* Section already exists. */
+ bfd_set_error (bfd_error_invalid_operation);
+ return NULL;
+ }
+
+ sect = bfd_make_section (abfd, GNU_DEBUGLINK);
+ if (sect == NULL)
+ return NULL;
+
+ if (! bfd_set_section_flags (abfd, sect,
+ SEC_HAS_CONTENTS | SEC_READONLY | SEC_DEBUGGING))
+ /* XXX Should we delete the section from the bfd ? */
+ return NULL;
+
+
+ debuglink_size = strlen (filename) + 1;
+ debuglink_size += 3;
+ debuglink_size &= ~3;
+ debuglink_size += 4;
+
+ if (! bfd_set_section_size (abfd, sect, debuglink_size))
+ /* XXX Should we delete the section from the bfd ? */
+ return NULL;
+
+ return sect;
+}
+
+
+/*
+FUNCTION
+ bfd_fill_in_gnu_debuglink_section
+
+SYNOPSIS
+ bfd_boolean bfd_fill_in_gnu_debuglink_section
+ (bfd *abfd, struct bfd_section *sect, const char *filename);
+
+DESCRIPTION
+
+ Takes a @var{BFD} and containing a .gnu_debuglink section @var{SECT}
+ and fills in the contents of the section to contain a link to the
+ specified @var{filename}. The filename should be relative to the
+ current directory.
+
+RETURNS
+ <<TRUE>> is returned if all is ok. Otherwise <<FALSE>> is returned
+ and bfd_error is set.
+*/
+
+bfd_boolean
+bfd_fill_in_gnu_debuglink_section (bfd *abfd,
+ struct bfd_section *sect,
+ const char *filename)
+{
+ bfd_size_type debuglink_size;
+ unsigned long crc32;
+ char * contents;
+ bfd_size_type crc_offset;
+ FILE * handle;
+ static char buffer[8 * 1024];
+ size_t count;
+
+ if (abfd == NULL || sect == NULL || filename == NULL)
+ {
+ bfd_set_error (bfd_error_invalid_operation);
+ return FALSE;
+ }
+
+ /* Make sure that we can read the file.
+ XXX - Should we attempt to locate the debug info file using the same
+ algorithm as gdb ? At the moment, since we are creating the
+ .gnu_debuglink section, we insist upon the user providing us with a
+ correct-for-section-creation-time path, but this need not conform to
+ the gdb location algorithm. */
+ handle = fopen (filename, FOPEN_RB);
+ if (handle == NULL)
+ {
+ bfd_set_error (bfd_error_system_call);
+ return FALSE;
+ }
+
+ crc32 = 0;
+ while ((count = fread (buffer, 1, sizeof buffer, handle)) > 0)
+ crc32 = bfd_calc_gnu_debuglink_crc32 (crc32, buffer, count);
+ fclose (handle);
+
+ /* Strip off any path components in filename,
+ now that we no longer need them. */
+ filename = lbasename (filename);
+
+ debuglink_size = strlen (filename) + 1;
+ debuglink_size += 3;
+ debuglink_size &= ~3;
+ debuglink_size += 4;
+
+ contents = malloc (debuglink_size);
+ if (contents == NULL)
+ {
+ /* XXX Should we delete the section from the bfd ? */
+ bfd_set_error (bfd_error_no_memory);
+ return FALSE;
+ }
+
+ strcpy (contents, filename);
+ crc_offset = debuglink_size - 4;
+
+ bfd_put_32 (abfd, crc32, contents + crc_offset);
+
+ if (! bfd_set_section_contents (abfd, sect, contents, 0, debuglink_size))
+ {
+ /* XXX Should we delete the section from the bfd ? */
+ free (contents);
+ return FALSE;
+ }
+
+ return TRUE;
+}