struct bfd_iovec
................

The struct bfd_iovec contains the internal file I/O class. Each BFD has an instance of this class and all file I/O is routed through it (it is assumed that the instance implements all methods listed below).

     struct bfd_iovec
     {
       /* To avoid problems with macros, a "b" rather than "f"
          prefix is prepended to each method name.  */
       /* Attempt to read/write NBYTES on ABFD's IOSTREAM storing/fetching
          bytes starting at PTR.  Return the number of bytes actually
          transfered (a read past end-of-file returns less than NBYTES),
          or -1 (setting bfd_error) if an error occurs.  */
       file_ptr (*bread) (struct bfd *abfd, void *ptr, file_ptr nbytes);
       file_ptr (*bwrite) (struct bfd *abfd, const void *ptr,
                           file_ptr nbytes);
       /* Return the current IOSTREAM file offset, or -1 (setting bfd_error
          if an error occurs.  */
       file_ptr (*btell) (struct bfd *abfd);
       /* For the following, on successful completion a value of 0 is returned.
          Otherwise, a value of -1 is returned (and bfd_error is set).  */
       int (*bseek) (struct bfd *abfd, file_ptr offset, int whence);
       int (*bclose) (struct bfd *abfd);
       int (*bflush) (struct bfd *abfd);
       int (*bstat) (struct bfd *abfd, struct stat *sb);
       /* Mmap a part of the files. ADDR, LEN, PROT, FLAGS and OFFSET are the usual
          mmap parameter, except that LEN and OFFSET do not need to be page
          aligned.  Returns (void *)-1 on failure, mmapped address on success.
          Also write in MAP_ADDR the address of the page aligned buffer and in
          MAP_LEN the size mapped (a page multiple).  Use unmap with MAP_ADDR and
          MAP_LEN to unmap.  */
       void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
                       int prot, int flags, file_ptr offset,
                       void **map_addr, bfd_size_type *map_len);
     };
     extern const struct bfd_iovec _bfd_memory_iovec;

bfd_read
........

 -- Function: bfd_size_type bfd_read (void *, bfd_size_type, bfd *) ATTRIBUTE_WARN_UNUSED_RESULT;
     Attempt to read SIZE bytes from ABFD's iostream to PTR. Return the amount read.

bfd_write
.........

 -- Function: bfd_size_type bfd_write (const void *, bfd_size_type, bfd *) ATTRIBUTE_WARN_UNUSED_RESULT;
     Attempt to write SIZE bytes to ABFD's iostream from PTR. Return the amount written.

bfd_tell
........

 -- Function: file_ptr bfd_tell (bfd *) ATTRIBUTE_WARN_UNUSED_RESULT;
     Return ABFD's iostream file position.

bfd_flush
.........

 -- Function: int bfd_flush (bfd *);
     Flush ABFD's iostream pending IO.

bfd_stat
........

 -- Function: int bfd_stat (bfd *, struct stat *) ATTRIBUTE_WARN_UNUSED_RESULT;
     Call fstat on ABFD's iostream.  Return 0 on success, and a negative value on failure.

bfd_seek
........

 -- Function: int bfd_seek (bfd *, file_ptr, int) ATTRIBUTE_WARN_UNUSED_RESULT;
     Call fseek on ABFD's iostream.  Return 0 on success, and a negative value on failure.

bfd_get_mtime
.............

 -- Function: long bfd_get_mtime (bfd *abfd);
     Return the file modification time (as read from the file system, or from the archive header for archive members).

bfd_get_size
............

 -- Function: ufile_ptr bfd_get_size (bfd *abfd);
     Return the file size (as read from file system) for the file associated with BFD ABFD.

     The initial motivation for, and use of, this routine is not so we can get the exact size of the object the BFD applies to, since that might not be generally possible (archive members for example). It would be ideal if someone could eventually modify it so that such results were guaranteed.

     Instead, we want to ask questions like "is this NNN byte sized object I'm about to try read from file offset YYY reasonable?" As as example of where we might do this, some object formats use string tables for which the first sizeof (long) bytes of the table contain the size of the table itself, including the size bytes. If an application tries to read what it thinks is one of these string tables, without some way to validate the size, and for some reason the size is wrong (byte swapping error, wrong location for the string table, etc.), the only clue is likely to be a read error when it tries to read the table, or a "virtual memory exhausted" error when it tries to allocate 15 bazillon bytes of space for the 15 bazillon byte table it is about to read. This function at least allows us to answer the question, "is the size reasonable?".

     A return value of zero indicates the file size is unknown.

bfd_get_file_size
.................

 -- Function: ufile_ptr bfd_get_file_size (bfd *abfd);
     Return the file size (as read from file system) for the file associated with BFD ABFD.  It supports both normal files and archive elements.

bfd_mmap
........

 -- Function: void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len, int prot, int flags, file_ptr offset, void **map_addr, bfd_size_type *map_len) ATTRIBUTE_WARN_UNUSED_RESULT;
     Return mmap()ed region of the file, if possible and implemented. LEN and OFFSET do not need to be page aligned.  The page aligned address and length are written to MAP_ADDR and MAP_LEN.

bfd_get_current_time
....................

 -- Function: time_t bfd_get_current_time (time_t now);
     Returns the current time.

     If the environment variable SOURCE_DATE_EPOCH is defined then this is parsed and its value is returned.  Otherwise if the paramter NOW is non-zero, then that is returned. Otherwise the result of the system call "time(NULL)" is returned.