Opening and closing BFDs
========================

Functions for opening and closing
---------------------------------

_bfd_new_bfd
............

 -- Function: bfd *_bfd_new_bfd (void);
     Return a new BFD.  All BFD's are allocated through this routine.

_bfd_new_bfd_contained_in
.........................

 -- Function: bfd *_bfd_new_bfd_contained_in (bfd *);
     Allocate a new BFD as a member of archive OBFD.

_bfd_free_cached_info
.....................

 -- Function: bool _bfd_free_cached_info (bfd *);
     Free objalloc memory.

bfd_fopen
.........

 -- Function: bfd *bfd_fopen (const char *filename, const char *target, const char *mode, int fd);
     Open the file FILENAME with the target TARGET. Return a pointer to the created BFD.  If FD is not -1, then fdopen is used to open the file; otherwise, fopen is used.  MODE is passed directly to fopen or fdopen.

     Calls bfd_find_target, so TARGET is interpreted as by that function.

     The new BFD is marked as cacheable iff FD is -1.

     If NULL is returned then an error has occured.   Possible errors are bfd_error_no_memory, bfd_error_invalid_target or system_call error.

     On error, FD is always closed.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_openr
.........

 -- Function: bfd *bfd_openr (const char *filename, const char *target);
     Open the file FILENAME (using fopen) with the target TARGET.  Return a pointer to the created BFD.

     Calls bfd_find_target, so TARGET is interpreted as by that function.

     If NULL is returned then an error has occured.   Possible errors are bfd_error_no_memory, bfd_error_invalid_target or system_call error.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_fdopenr
...........

 -- Function: bfd *bfd_fdopenr (const char *filename, const char *target, int fd);
     bfd_fdopenr is to bfd_fopenr much like fdopen is to fopen.  It opens a BFD on a file already described by the FD supplied.

     When the file is later bfd_closed, the file descriptor will be closed.  If the caller desires that this file descriptor be cached by BFD (opened as needed, closed as needed to free descriptors for other opens), with the supplied FD used as an initial file descriptor (but subject to closure at any time), call bfd_set_cacheable(bfd, 1) on the returned BFD.  The default is to assume no caching; the file descriptor will remain open until bfd_close, and will not be affected by BFD operations on other files.

     Possible errors are bfd_error_no_memory, bfd_error_invalid_target and bfd_error_system_call.

     On error, FD is closed.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_fdopenw
...........

 -- Function: bfd *bfd_fdopenw (const char *filename, const char *target, int fd);
     bfd_fdopenw is exactly like bfd_fdopenr with the exception that the resulting BFD is suitable for output.

bfd_openstreamr
...............

 -- Function: bfd *bfd_openstreamr (const char * filename, const char * target, void * stream);
     Open a BFD for read access on an existing stdio stream.  When the BFD is passed to bfd_close, the stream will be closed.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_openr_iovec
...............

 -- Function: bfd *bfd_openr_iovec (const char *filename, const char *target, void *(*open_func) (struct bfd *nbfd, void *open_closure), void *open_closure, file_ptr (*pread_func) (struct bfd *nbfd, void *stream, void *buf, file_ptr nbytes, file_ptr offset), int (*close_func) (struct bfd *nbfd, void *stream), int (*stat_func) (struct bfd *abfd, void *stream, struct stat *sb));
     Create and return a BFD backed by a read-only STREAM. The STREAM is created using OPEN_FUNC, accessed using PREAD_FUNC and destroyed using CLOSE_FUNC.

     Calls bfd_find_target, so TARGET is interpreted as by that function.

     Calls OPEN_FUNC (which can call bfd_zalloc and bfd_get_filename) to obtain the read-only stream backing the BFD.  OPEN_FUNC either succeeds returning the non-NULL STREAM, or fails returning NULL (setting bfd_error).

     Calls PREAD_FUNC to request NBYTES of data from STREAM starting at OFFSET (e.g., via a call to bfd_read).  PREAD_FUNC either succeeds returning the number of bytes read (which can be less than NBYTES when end-of-file), or fails returning -1 (setting bfd_error).

     Calls CLOSE_FUNC when the BFD is later closed using bfd_close.  CLOSE_FUNC either succeeds returning 0, or fails returning -1 (setting bfd_error).

     Calls STAT_FUNC to fill in a stat structure for bfd_stat, bfd_get_size, and bfd_get_mtime calls.  STAT_FUNC returns 0 on success, or returns -1 on failure (setting bfd_error).

     If bfd_openr_iovec returns NULL then an error has occurred.  Possible errors are bfd_error_no_memory, bfd_error_invalid_target and bfd_error_system_call.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_openw
.........

 -- Function: bfd *bfd_openw (const char *filename, const char *target);
     Create a BFD, associated with file FILENAME, using the file format TARGET, and return a pointer to it.

     Possible errors are bfd_error_system_call, bfd_error_no_memory, bfd_error_invalid_target.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_elf_bfd_from_remote_memory
..............................

 -- Function: bfd *bfd_elf_bfd_from_remote_memory (bfd *templ, bfd_vma ehdr_vma, bfd_size_type size, bfd_vma *loadbasep, int (*target_read_memory) (bfd_vma vma, bfd_byte *myaddr, bfd_size_type len));
     Create a new BFD as if by bfd_openr.  Rather than opening a file, reconstruct an ELF file by reading the segments out of remote memory based on the ELF file header at EHDR_VMA and the ELF program headers it points to.  If non-zero, SIZE is the known extent of the object.  If not null, *LOADBASEP is filled in with the difference between the VMAs from which the segments were read, and the VMAs the file headers (and hence BFD's idea of each section's VMA) put them at.

     The function TARGET_READ_MEMORY is called to copy LEN bytes from the remote memory at target address VMA into the local buffer at MYADDR; it should return zero on success or an errno code on failure.  TEMPL must be a BFD for an ELF target with the word size and byte order found in the remote memory.

bfd_close
.........

 -- Function: bool bfd_close (bfd *abfd);
     Close a BFD. If the BFD was open for writing, then pending operations are completed and the file written out and closed. If the created file is executable, then chmod is called to mark it as such.

     All memory attached to the BFD is released.

     The file descriptor associated with the BFD is closed (even if it was passed in to BFD by bfd_fdopenr).

     TRUE is returned if all is ok, otherwise FALSE.

bfd_close_all_done
..................

 -- Function: bool bfd_close_all_done (bfd *);
     Close a BFD.  Differs from bfd_close since it does not complete any pending operations.  This routine would be used if the application had just used BFD for swapping and didn't want to use any of the writing code.

     If the created file is executable, then chmod is called to mark it as such.

     All memory attached to the BFD is released.

     TRUE is returned if all is ok, otherwise FALSE.

bfd_create
..........

 -- Function: bfd *bfd_create (const char *filename, bfd *templ);
     Create a new BFD in the manner of bfd_openw, but without opening a file. The new BFD takes the target from the target used by TEMPL. The format is always set to bfd_object.

     A copy of the FILENAME argument is stored in the newly created BFD.  It can be accessed via the bfd_get_filename() macro.

bfd_make_writable
.................

 -- Function: bool bfd_make_writable (bfd *abfd);
     Takes a BFD as created by bfd_create and converts it into one like as returned by bfd_openw.  It does this by converting the BFD to BFD_IN_MEMORY.  It's assumed that you will call bfd_make_readable on this bfd later.

     TRUE is returned if all is ok, otherwise FALSE.

bfd_make_readable
.................

 -- Function: bool bfd_make_readable (bfd *abfd);
     Takes a BFD as created by bfd_create and bfd_make_writable and converts it into one like as returned by bfd_openr.  It does this by writing the contents out to the memory buffer, then reversing the direction.

     TRUE is returned if all is ok, otherwise FALSE.

bfd_calc_gnu_debuglink_crc32
............................

 -- Function: uint32_t bfd_calc_gnu_debuglink_crc32 (uint32_t crc, const bfd_byte *buf, bfd_size_type len);
     Computes a CRC value as used in the .gnu_debuglink section. Advances the previously computed CRC value by computing and adding in the crc32 for LEN bytes of BUF.

     Return the updated CRC32 value.

bfd_get_debug_link_info
.......................

 -- Function: char *bfd_get_debug_link_info (bfd *abfd, uint32_t *crc32_out);
     Extracts the filename and CRC32 value for any separate debug information file associated with ABFD.

     Returns the filename of the associated debug information file, or NULL if there is no such file.  If the filename was found then the contents of CRC32_OUT are updated to hold the corresponding CRC32 value for the file.

     The returned filename is allocated with malloc; freeing it is the responsibility of the caller.

bfd_get_alt_debug_link_info
...........................

 -- Function: char *bfd_get_alt_debug_link_info (bfd * abfd, bfd_size_type *buildid_len, bfd_byte **buildid_out);
     Fetch the filename and BuildID value for any alternate debuginfo associated with ABFD.  Return NULL if no such info found, otherwise return filename and update BUILDID_LEN and BUILDID_OUT.  The returned filename and build_id are allocated with malloc; freeing them is the responsibility of the caller.

bfd_follow_gnu_debuglink
........................

 -- Function: char *bfd_follow_gnu_debuglink (bfd *abfd, const char *dir);
     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 DIR, and if found returns the full filename.

     If DIR is NULL, the search will take place starting at the current directory.

     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.

bfd_follow_gnu_debugaltlink
...........................

 -- Function: char *bfd_follow_gnu_debugaltlink (bfd *abfd, const char *dir);
     Takes a BFD and searches it for a .gnu_debugaltlink section.  If this section is found, it examines the section for the name of a file containing auxiliary debugging information.  It then searches the filesystem for this file in a set of standard locations, including the directory tree rooted at DIR, and if found returns the full filename.

     If DIR is NULL, the search will take place starting at the current directory.

     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.

bfd_create_gnu_debuglink_section
................................

 -- Function: struct bfd_section *bfd_create_gnu_debuglink_section (bfd *abfd, const char *filename);
     Takes a BFD and adds a .gnu_debuglink section to it.  The section is sized to be big enough to contain a link to the specified FILENAME.

     A pointer to the new section is returned if all is ok.  Otherwise NULL is returned and bfd_error is set.

bfd_fill_in_gnu_debuglink_section
.................................

 -- Function: bool bfd_fill_in_gnu_debuglink_section (bfd *abfd, struct bfd_section *sect, const char *filename);
     Takes a BFD and containing a .gnu_debuglink section SECT and fills in the contents of the section to contain a link to the specified FILENAME.  The filename should be absolute or relative to the current directory.

     TRUE is returned if all is ok.  Otherwise FALSE is returned and bfd_error is set.

bfd_follow_build_id_debuglink
.............................

 -- Function: char *bfd_follow_build_id_debuglink (bfd *abfd, const char *dir);
     Takes ABFD and searches it for a .note.gnu.build-id section. If this section is found, it extracts the value of the NT_GNU_BUILD_ID note, which should be a hexadecimal value NNNN+NN (for 32+ hex digits).  It then searches the filesystem for a file named .BUILD-ID/NN/NN+NN.DEBUG in a set of standard locations, including the directory tree rooted at DIR.  The filename of the first matching file to be found is returned.  A matching file should contain a .note.gnu.build-id section with the same NNNN+NN note as ABFD, although this check is currently not implemented.

     If DIR is NULL, the search will take place starting at the current directory.

     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.

bfd_set_filename
................

 -- Function: const char *bfd_set_filename (bfd *abfd, const char *filename);
     Set the filename of ABFD, copying the FILENAME parameter to bfd_alloc'd memory owned by ABFD.  Returns a pointer the newly allocated name, or NULL if the allocation failed.