1188 lines
44 KiB
Plaintext
1188 lines
44 KiB
Plaintext
|
This is bfd.info, produced by makeinfo version 4.0 from bfd.texinfo.
|
|||
|
|
|||
|
START-INFO-DIR-ENTRY
|
|||
|
* Bfd: (bfd). The Binary File Descriptor library.
|
|||
|
END-INFO-DIR-ENTRY
|
|||
|
|
|||
|
This file documents the BFD library.
|
|||
|
|
|||
|
Copyright (C) 1991 Free Software Foundation, Inc.
|
|||
|
|
|||
|
Permission is granted to make and distribute verbatim copies of this
|
|||
|
manual provided the copyright notice and this permission notice are
|
|||
|
preserved on all copies.
|
|||
|
|
|||
|
Permission is granted to copy and distribute modified versions of
|
|||
|
this manual under the conditions for verbatim copying, subject to the
|
|||
|
terms of the GNU General Public License, which includes the provision
|
|||
|
that the entire resulting derived work is distributed under the terms
|
|||
|
of a permission notice identical to this one.
|
|||
|
|
|||
|
Permission is granted to copy and distribute translations of this
|
|||
|
manual into another language, under the above conditions for modified
|
|||
|
versions.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: typedef asection, Next: section prototypes, Prev: Section Output, Up: Sections
|
|||
|
|
|||
|
typedef asection
|
|||
|
----------------
|
|||
|
|
|||
|
Here is the section structure:
|
|||
|
|
|||
|
|
|||
|
/* This structure is used for a comdat section, as in PE. A comdat
|
|||
|
section is associated with a particular symbol. When the linker
|
|||
|
sees a comdat section, it keeps only one of the sections with a
|
|||
|
given name and associated with a given symbol. */
|
|||
|
|
|||
|
struct bfd_comdat_info
|
|||
|
{
|
|||
|
/* The name of the symbol associated with a comdat section. */
|
|||
|
const char *name;
|
|||
|
|
|||
|
/* The local symbol table index of the symbol associated with a
|
|||
|
comdat section. This is only meaningful to the object file format
|
|||
|
specific code; it is not an index into the list returned by
|
|||
|
bfd_canonicalize_symtab. */
|
|||
|
long symbol;
|
|||
|
|
|||
|
/* If this section is being discarded, the linker uses this field
|
|||
|
to point to the input section which is being kept. */
|
|||
|
struct sec *sec;
|
|||
|
};
|
|||
|
|
|||
|
typedef struct sec
|
|||
|
{
|
|||
|
/* The name of the section; the name isn't a copy, the pointer is
|
|||
|
the same as that passed to bfd_make_section. */
|
|||
|
|
|||
|
CONST char *name;
|
|||
|
|
|||
|
/* Which section is it; 0..nth. */
|
|||
|
|
|||
|
int index;
|
|||
|
|
|||
|
/* The next section in the list belonging to the BFD, or NULL. */
|
|||
|
|
|||
|
struct sec *next;
|
|||
|
|
|||
|
/* The field flags contains attributes of the section. Some
|
|||
|
flags are read in from the object file, and some are
|
|||
|
synthesized from other information. */
|
|||
|
|
|||
|
flagword flags;
|
|||
|
|
|||
|
#define SEC_NO_FLAGS 0x000
|
|||
|
|
|||
|
/* Tells the OS to allocate space for this section when loading.
|
|||
|
This is clear for a section containing debug information
|
|||
|
only. */
|
|||
|
#define SEC_ALLOC 0x001
|
|||
|
|
|||
|
/* Tells the OS to load the section from the file when loading.
|
|||
|
This is clear for a .bss section. */
|
|||
|
#define SEC_LOAD 0x002
|
|||
|
|
|||
|
/* The section contains data still to be relocated, so there is
|
|||
|
some relocation information too. */
|
|||
|
#define SEC_RELOC 0x004
|
|||
|
|
|||
|
#if 0 /* Obsolete ? */
|
|||
|
#define SEC_BALIGN 0x008
|
|||
|
#endif
|
|||
|
|
|||
|
/* A signal to the OS that the section contains read only
|
|||
|
data. */
|
|||
|
#define SEC_READONLY 0x010
|
|||
|
|
|||
|
/* The section contains code only. */
|
|||
|
#define SEC_CODE 0x020
|
|||
|
|
|||
|
/* The section contains data only. */
|
|||
|
#define SEC_DATA 0x040
|
|||
|
|
|||
|
/* The section will reside in ROM. */
|
|||
|
#define SEC_ROM 0x080
|
|||
|
|
|||
|
/* The section contains constructor information. This section
|
|||
|
type is used by the linker to create lists of constructors and
|
|||
|
destructors used by `g++'. When a back end sees a symbol
|
|||
|
which should be used in a constructor list, it creates a new
|
|||
|
section for the type of name (e.g., `__CTOR_LIST__'), attaches
|
|||
|
the symbol to it, and builds a relocation. To build the lists
|
|||
|
of constructors, all the linker has to do is catenate all the
|
|||
|
sections called `__CTOR_LIST__' and relocate the data
|
|||
|
contained within - exactly the operations it would peform on
|
|||
|
standard data. */
|
|||
|
#define SEC_CONSTRUCTOR 0x100
|
|||
|
|
|||
|
/* The section is a constructor, and should be placed at the
|
|||
|
end of the text, data, or bss section(?). */
|
|||
|
#define SEC_CONSTRUCTOR_TEXT 0x1100
|
|||
|
#define SEC_CONSTRUCTOR_DATA 0x2100
|
|||
|
#define SEC_CONSTRUCTOR_BSS 0x3100
|
|||
|
|
|||
|
/* The section has contents - a data section could be
|
|||
|
`SEC_ALLOC' | `SEC_HAS_CONTENTS'; a debug section could be
|
|||
|
`SEC_HAS_CONTENTS' */
|
|||
|
#define SEC_HAS_CONTENTS 0x200
|
|||
|
|
|||
|
/* An instruction to the linker to not output the section
|
|||
|
even if it has information which would normally be written. */
|
|||
|
#define SEC_NEVER_LOAD 0x400
|
|||
|
|
|||
|
/* The section is a COFF shared library section. This flag is
|
|||
|
only for the linker. If this type of section appears in
|
|||
|
the input file, the linker must copy it to the output file
|
|||
|
without changing the vma or size. FIXME: Although this
|
|||
|
was originally intended to be general, it really is COFF
|
|||
|
specific (and the flag was renamed to indicate this). It
|
|||
|
might be cleaner to have some more general mechanism to
|
|||
|
allow the back end to control what the linker does with
|
|||
|
sections. */
|
|||
|
#define SEC_COFF_SHARED_LIBRARY 0x800
|
|||
|
|
|||
|
/* The section contains common symbols (symbols may be defined
|
|||
|
multiple times, the value of a symbol is the amount of
|
|||
|
space it requires, and the largest symbol value is the one
|
|||
|
used). Most targets have exactly one of these (which we
|
|||
|
translate to bfd_com_section_ptr), but ECOFF has two. */
|
|||
|
#define SEC_IS_COMMON 0x8000
|
|||
|
|
|||
|
/* The section contains only debugging information. For
|
|||
|
example, this is set for ELF .debug and .stab sections.
|
|||
|
strip tests this flag to see if a section can be
|
|||
|
discarded. */
|
|||
|
#define SEC_DEBUGGING 0x10000
|
|||
|
|
|||
|
/* The contents of this section are held in memory pointed to
|
|||
|
by the contents field. This is checked by
|
|||
|
bfd_get_section_contents, and the data is retrieved from
|
|||
|
memory if appropriate. */
|
|||
|
#define SEC_IN_MEMORY 0x20000
|
|||
|
|
|||
|
/* The contents of this section are to be excluded by the
|
|||
|
linker for executable and shared objects unless those
|
|||
|
objects are to be further relocated. */
|
|||
|
#define SEC_EXCLUDE 0x40000
|
|||
|
|
|||
|
/* The contents of this section are to be sorted by the
|
|||
|
based on the address specified in the associated symbol
|
|||
|
table. */
|
|||
|
#define SEC_SORT_ENTRIES 0x80000
|
|||
|
|
|||
|
/* When linking, duplicate sections of the same name should be
|
|||
|
discarded, rather than being combined into a single section as
|
|||
|
is usually done. This is similar to how common symbols are
|
|||
|
handled. See SEC_LINK_DUPLICATES below. */
|
|||
|
#define SEC_LINK_ONCE 0x100000
|
|||
|
|
|||
|
/* If SEC_LINK_ONCE is set, this bitfield describes how the linker
|
|||
|
should handle duplicate sections. */
|
|||
|
#define SEC_LINK_DUPLICATES 0x600000
|
|||
|
|
|||
|
/* This value for SEC_LINK_DUPLICATES means that duplicate
|
|||
|
sections with the same name should simply be discarded. */
|
|||
|
#define SEC_LINK_DUPLICATES_DISCARD 0x0
|
|||
|
|
|||
|
/* This value for SEC_LINK_DUPLICATES means that the linker
|
|||
|
should warn if there are any duplicate sections, although
|
|||
|
it should still only link one copy. */
|
|||
|
#define SEC_LINK_DUPLICATES_ONE_ONLY 0x200000
|
|||
|
|
|||
|
/* This value for SEC_LINK_DUPLICATES means that the linker
|
|||
|
should warn if any duplicate sections are a different size. */
|
|||
|
#define SEC_LINK_DUPLICATES_SAME_SIZE 0x400000
|
|||
|
|
|||
|
/* This value for SEC_LINK_DUPLICATES means that the linker
|
|||
|
should warn if any duplicate sections contain different
|
|||
|
contents. */
|
|||
|
#define SEC_LINK_DUPLICATES_SAME_CONTENTS 0x600000
|
|||
|
|
|||
|
/* This section was created by the linker as part of dynamic
|
|||
|
relocation or other arcane processing. It is skipped when
|
|||
|
going through the first-pass output, trusting that someone
|
|||
|
else up the line will take care of it later. */
|
|||
|
#define SEC_LINKER_CREATED 0x800000
|
|||
|
|
|||
|
/* This section should not be subject to garbage collection. */
|
|||
|
#define SEC_KEEP 0x1000000
|
|||
|
|
|||
|
/* This section contains "short" data, and should be placed
|
|||
|
"near" the GP. */
|
|||
|
#define SEC_SMALL_DATA 0x2000000
|
|||
|
|
|||
|
/* This section contains data which may be shared with other
|
|||
|
executables or shared objects. */
|
|||
|
#define SEC_SHARED 0x4000000
|
|||
|
|
|||
|
/* End of section flags. */
|
|||
|
|
|||
|
/* Some internal packed boolean fields. */
|
|||
|
|
|||
|
/* See the vma field. */
|
|||
|
unsigned int user_set_vma : 1;
|
|||
|
|
|||
|
/* Whether relocations have been processed. */
|
|||
|
unsigned int reloc_done : 1;
|
|||
|
|
|||
|
/* A mark flag used by some of the linker backends. */
|
|||
|
unsigned int linker_mark : 1;
|
|||
|
|
|||
|
/* A mark flag used by some linker backends for garbage collection. */
|
|||
|
unsigned int gc_mark : 1;
|
|||
|
|
|||
|
/* End of internal packed boolean fields. */
|
|||
|
|
|||
|
/* The virtual memory address of the section - where it will be
|
|||
|
at run time. The symbols are relocated against this. The
|
|||
|
user_set_vma flag is maintained by bfd; if it's not set, the
|
|||
|
backend can assign addresses (for example, in `a.out', where
|
|||
|
the default address for `.data' is dependent on the specific
|
|||
|
target and various flags). */
|
|||
|
|
|||
|
bfd_vma vma;
|
|||
|
|
|||
|
/* The load address of the section - where it would be in a
|
|||
|
rom image; really only used for writing section header
|
|||
|
information. */
|
|||
|
|
|||
|
bfd_vma lma;
|
|||
|
|
|||
|
/* The size of the section in octets, as it will be output.
|
|||
|
Contains a value even if the section has no contents (e.g., the
|
|||
|
size of `.bss'). This will be filled in after relocation. */
|
|||
|
|
|||
|
bfd_size_type _cooked_size;
|
|||
|
|
|||
|
/* The original size on disk of the section, in octets. Normally this
|
|||
|
value is the same as the size, but if some relaxing has
|
|||
|
been done, then this value will be bigger. */
|
|||
|
|
|||
|
bfd_size_type _raw_size;
|
|||
|
|
|||
|
/* If this section is going to be output, then this value is the
|
|||
|
offset in *bytes* into the output section of the first byte in the
|
|||
|
input section (byte ==> smallest addressable unit on the
|
|||
|
target). In most cases, if this was going to start at the
|
|||
|
100th octet (8-bit quantity) in the output section, this value
|
|||
|
would be 100. However, if the target byte size is 16 bits
|
|||
|
(bfd_octets_per_byte is "2"), this value would be 50. */
|
|||
|
|
|||
|
bfd_vma output_offset;
|
|||
|
|
|||
|
/* The output section through which to map on output. */
|
|||
|
|
|||
|
struct sec *output_section;
|
|||
|
|
|||
|
/* The alignment requirement of the section, as an exponent of 2 -
|
|||
|
e.g., 3 aligns to 2^3 (or 8). */
|
|||
|
|
|||
|
unsigned int alignment_power;
|
|||
|
|
|||
|
/* If an input section, a pointer to a vector of relocation
|
|||
|
records for the data in this section. */
|
|||
|
|
|||
|
struct reloc_cache_entry *relocation;
|
|||
|
|
|||
|
/* If an output section, a pointer to a vector of pointers to
|
|||
|
relocation records for the data in this section. */
|
|||
|
|
|||
|
struct reloc_cache_entry **orelocation;
|
|||
|
|
|||
|
/* The number of relocation records in one of the above */
|
|||
|
|
|||
|
unsigned reloc_count;
|
|||
|
|
|||
|
/* Information below is back end specific - and not always used
|
|||
|
or updated. */
|
|||
|
|
|||
|
/* File position of section data */
|
|||
|
|
|||
|
file_ptr filepos;
|
|||
|
|
|||
|
/* File position of relocation info */
|
|||
|
|
|||
|
file_ptr rel_filepos;
|
|||
|
|
|||
|
/* File position of line data */
|
|||
|
|
|||
|
file_ptr line_filepos;
|
|||
|
|
|||
|
/* Pointer to data for applications */
|
|||
|
|
|||
|
PTR userdata;
|
|||
|
|
|||
|
/* If the SEC_IN_MEMORY flag is set, this points to the actual
|
|||
|
contents. */
|
|||
|
unsigned char *contents;
|
|||
|
|
|||
|
/* Attached line number information */
|
|||
|
|
|||
|
alent *lineno;
|
|||
|
|
|||
|
/* Number of line number records */
|
|||
|
|
|||
|
unsigned int lineno_count;
|
|||
|
|
|||
|
/* Optional information about a COMDAT entry; NULL if not COMDAT */
|
|||
|
|
|||
|
struct bfd_comdat_info *comdat;
|
|||
|
|
|||
|
/* When a section is being output, this value changes as more
|
|||
|
linenumbers are written out */
|
|||
|
|
|||
|
file_ptr moving_line_filepos;
|
|||
|
|
|||
|
/* What the section number is in the target world */
|
|||
|
|
|||
|
int target_index;
|
|||
|
|
|||
|
PTR used_by_bfd;
|
|||
|
|
|||
|
/* If this is a constructor section then here is a list of the
|
|||
|
relocations created to relocate items within it. */
|
|||
|
|
|||
|
struct relent_chain *constructor_chain;
|
|||
|
|
|||
|
/* The BFD which owns the section. */
|
|||
|
|
|||
|
bfd *owner;
|
|||
|
|
|||
|
/* A symbol which points at this section only */
|
|||
|
struct symbol_cache_entry *symbol;
|
|||
|
struct symbol_cache_entry **symbol_ptr_ptr;
|
|||
|
|
|||
|
struct bfd_link_order *link_order_head;
|
|||
|
struct bfd_link_order *link_order_tail;
|
|||
|
} asection ;
|
|||
|
|
|||
|
/* These sections are global, and are managed by BFD. The application
|
|||
|
and target back end are not permitted to change the values in
|
|||
|
these sections. New code should use the section_ptr macros rather
|
|||
|
than referring directly to the const sections. The const sections
|
|||
|
may eventually vanish. */
|
|||
|
#define BFD_ABS_SECTION_NAME "*ABS*"
|
|||
|
#define BFD_UND_SECTION_NAME "*UND*"
|
|||
|
#define BFD_COM_SECTION_NAME "*COM*"
|
|||
|
#define BFD_IND_SECTION_NAME "*IND*"
|
|||
|
|
|||
|
/* the absolute section */
|
|||
|
extern const asection bfd_abs_section;
|
|||
|
#define bfd_abs_section_ptr ((asection *) &bfd_abs_section)
|
|||
|
#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr)
|
|||
|
/* Pointer to the undefined section */
|
|||
|
extern const asection bfd_und_section;
|
|||
|
#define bfd_und_section_ptr ((asection *) &bfd_und_section)
|
|||
|
#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr)
|
|||
|
/* Pointer to the common section */
|
|||
|
extern const asection bfd_com_section;
|
|||
|
#define bfd_com_section_ptr ((asection *) &bfd_com_section)
|
|||
|
/* Pointer to the indirect section */
|
|||
|
extern const asection bfd_ind_section;
|
|||
|
#define bfd_ind_section_ptr ((asection *) &bfd_ind_section)
|
|||
|
#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr)
|
|||
|
|
|||
|
extern const struct symbol_cache_entry * const bfd_abs_symbol;
|
|||
|
extern const struct symbol_cache_entry * const bfd_com_symbol;
|
|||
|
extern const struct symbol_cache_entry * const bfd_und_symbol;
|
|||
|
extern const struct symbol_cache_entry * const bfd_ind_symbol;
|
|||
|
#define bfd_get_section_size_before_reloc(section) \
|
|||
|
((section)->reloc_done ? (abort (), (bfd_size_type) 1) \
|
|||
|
: (section)->_raw_size)
|
|||
|
#define bfd_get_section_size_after_reloc(section) \
|
|||
|
((section)->reloc_done ? (section)->_cooked_size \
|
|||
|
: (abort (), (bfd_size_type) 1))
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: section prototypes, Prev: typedef asection, Up: Sections
|
|||
|
|
|||
|
Section prototypes
|
|||
|
------------------
|
|||
|
|
|||
|
These are the functions exported by the section handling part of BFD.
|
|||
|
|
|||
|
`bfd_get_section_by_name'
|
|||
|
.........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
|
|||
|
*Description*
|
|||
|
Run through ABFD and return the one of the `asection's whose name
|
|||
|
matches NAME, otherwise `NULL'. *Note Sections::, for more information.
|
|||
|
|
|||
|
This should only be used in special cases; the normal way to process
|
|||
|
all sections of a given name is to use `bfd_map_over_sections' and
|
|||
|
`strcmp' on the name (or better yet, base it on the section flags or
|
|||
|
something else) for each section.
|
|||
|
|
|||
|
`bfd_make_section_old_way'
|
|||
|
..........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
asection *bfd_make_section_old_way(bfd *abfd, CONST char *name);
|
|||
|
*Description*
|
|||
|
Create a new empty section called NAME and attach it to the end of the
|
|||
|
chain of sections for the BFD ABFD. An attempt to create a section with
|
|||
|
a name which is already in use returns its pointer without changing the
|
|||
|
section chain.
|
|||
|
|
|||
|
It has the funny name since this is the way it used to be before it
|
|||
|
was rewritten....
|
|||
|
|
|||
|
Possible errors are:
|
|||
|
* `bfd_error_invalid_operation' - If output has already started for
|
|||
|
this BFD.
|
|||
|
|
|||
|
* `bfd_error_no_memory' - If memory allocation fails.
|
|||
|
|
|||
|
`bfd_make_section_anyway'
|
|||
|
.........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
asection *bfd_make_section_anyway(bfd *abfd, CONST char *name);
|
|||
|
*Description*
|
|||
|
Create a new empty section called NAME and attach it to the end of the
|
|||
|
chain of sections for ABFD. Create a new section even if there is
|
|||
|
already a section with that name.
|
|||
|
|
|||
|
Return `NULL' and set `bfd_error' on error; possible errors are:
|
|||
|
* `bfd_error_invalid_operation' - If output has already started for
|
|||
|
ABFD.
|
|||
|
|
|||
|
* `bfd_error_no_memory' - If memory allocation fails.
|
|||
|
|
|||
|
`bfd_make_section'
|
|||
|
..................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
asection *bfd_make_section(bfd *, CONST char *name);
|
|||
|
*Description*
|
|||
|
Like `bfd_make_section_anyway', but return `NULL' (without calling
|
|||
|
bfd_set_error ()) without changing the section chain if there is
|
|||
|
already a section named NAME. If there is an error, return `NULL' and
|
|||
|
set `bfd_error'.
|
|||
|
|
|||
|
`bfd_set_section_flags'
|
|||
|
.......................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_set_section_flags(bfd *abfd, asection *sec, flagword flags);
|
|||
|
*Description*
|
|||
|
Set the attributes of the section SEC in the BFD ABFD to the value
|
|||
|
FLAGS. Return `true' on success, `false' on error. Possible error
|
|||
|
returns are:
|
|||
|
|
|||
|
* `bfd_error_invalid_operation' - The section cannot have one or
|
|||
|
more of the attributes requested. For example, a .bss section in
|
|||
|
`a.out' may not have the `SEC_HAS_CONTENTS' field set.
|
|||
|
|
|||
|
`bfd_map_over_sections'
|
|||
|
.......................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
void bfd_map_over_sections(bfd *abfd,
|
|||
|
void (*func)(bfd *abfd,
|
|||
|
asection *sect,
|
|||
|
PTR obj),
|
|||
|
PTR obj);
|
|||
|
*Description*
|
|||
|
Call the provided function FUNC for each section attached to the BFD
|
|||
|
ABFD, passing OBJ as an argument. The function will be called as if by
|
|||
|
|
|||
|
func(abfd, the_section, obj);
|
|||
|
|
|||
|
This is the prefered method for iterating over sections; an
|
|||
|
alternative would be to use a loop:
|
|||
|
|
|||
|
section *p;
|
|||
|
for (p = abfd->sections; p != NULL; p = p->next)
|
|||
|
func(abfd, p, ...)
|
|||
|
|
|||
|
`bfd_set_section_size'
|
|||
|
......................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_set_section_size(bfd *abfd, asection *sec, bfd_size_type val);
|
|||
|
*Description*
|
|||
|
Set SEC to the size VAL. If the operation is ok, then `true' is
|
|||
|
returned, else `false'.
|
|||
|
|
|||
|
Possible error returns:
|
|||
|
* `bfd_error_invalid_operation' - Writing has started to the BFD, so
|
|||
|
setting the size is invalid.
|
|||
|
|
|||
|
`bfd_set_section_contents'
|
|||
|
..........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_set_section_contents
|
|||
|
(bfd *abfd,
|
|||
|
asection *section,
|
|||
|
PTR data,
|
|||
|
file_ptr offset,
|
|||
|
bfd_size_type count);
|
|||
|
*Description*
|
|||
|
Sets the contents of the section SECTION in BFD ABFD to the data
|
|||
|
starting in memory at DATA. The data is written to the output section
|
|||
|
starting at offset OFFSET for COUNT octets.
|
|||
|
|
|||
|
Normally `true' is returned, else `false'. Possible error returns
|
|||
|
are:
|
|||
|
* `bfd_error_no_contents' - The output section does not have the
|
|||
|
`SEC_HAS_CONTENTS' attribute, so nothing can be written to it.
|
|||
|
|
|||
|
* and some more too
|
|||
|
This routine is front end to the back end function
|
|||
|
`_bfd_set_section_contents'.
|
|||
|
|
|||
|
`bfd_get_section_contents'
|
|||
|
..........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_get_section_contents
|
|||
|
(bfd *abfd, asection *section, PTR location,
|
|||
|
file_ptr offset, bfd_size_type count);
|
|||
|
*Description*
|
|||
|
Read data from SECTION in BFD ABFD into memory starting at LOCATION.
|
|||
|
The data is read at an offset of OFFSET from the start of the input
|
|||
|
section, and is read for COUNT bytes.
|
|||
|
|
|||
|
If the contents of a constructor with the `SEC_CONSTRUCTOR' flag set
|
|||
|
are requested or if the section does not have the `SEC_HAS_CONTENTS'
|
|||
|
flag set, then the LOCATION is filled with zeroes. If no errors occur,
|
|||
|
`true' is returned, else `false'.
|
|||
|
|
|||
|
`bfd_copy_private_section_data'
|
|||
|
...............................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_copy_private_section_data(bfd *ibfd, asection *isec, bfd *obfd, asection *osec);
|
|||
|
*Description*
|
|||
|
Copy private section information from ISEC in the BFD IBFD to the
|
|||
|
section OSEC in the BFD OBFD. Return `true' on success, `false' on
|
|||
|
error. Possible error returns are:
|
|||
|
|
|||
|
* `bfd_error_no_memory' - Not enough memory exists to create private
|
|||
|
data for OSEC.
|
|||
|
|
|||
|
#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \
|
|||
|
BFD_SEND (obfd, _bfd_copy_private_section_data, \
|
|||
|
(ibfd, isection, obfd, osection))
|
|||
|
|
|||
|
`_bfd_strip_section_from_output'
|
|||
|
................................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
void _bfd_strip_section_from_output
|
|||
|
(struct bfd_link_info *info, asection *section);
|
|||
|
*Description*
|
|||
|
Remove SECTION from the output. If the output section becomes empty,
|
|||
|
remove it from the output bfd. INFO may be NULL; if it is not, it is
|
|||
|
used to decide whether the output section is empty.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Symbols, Next: Archives, Prev: Sections, Up: BFD front end
|
|||
|
|
|||
|
Symbols
|
|||
|
=======
|
|||
|
|
|||
|
BFD tries to maintain as much symbol information as it can when it
|
|||
|
moves information from file to file. BFD passes information to
|
|||
|
applications though the `asymbol' structure. When the application
|
|||
|
requests the symbol table, BFD reads the table in the native form and
|
|||
|
translates parts of it into the internal format. To maintain more than
|
|||
|
the information passed to applications, some targets keep some
|
|||
|
information "behind the scenes" in a structure only the particular back
|
|||
|
end knows about. For example, the coff back end keeps the original
|
|||
|
symbol table structure as well as the canonical structure when a BFD is
|
|||
|
read in. On output, the coff back end can reconstruct the output symbol
|
|||
|
table so that no information is lost, even information unique to coff
|
|||
|
which BFD doesn't know or understand. If a coff symbol table were read,
|
|||
|
but were written through an a.out back end, all the coff specific
|
|||
|
information would be lost. The symbol table of a BFD is not necessarily
|
|||
|
read in until a canonicalize request is made. Then the BFD back end
|
|||
|
fills in a table provided by the application with pointers to the
|
|||
|
canonical information. To output symbols, the application provides BFD
|
|||
|
with a table of pointers to pointers to `asymbol's. This allows
|
|||
|
applications like the linker to output a symbol as it was read, since
|
|||
|
the "behind the scenes" information will be still available.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* Reading Symbols::
|
|||
|
* Writing Symbols::
|
|||
|
* Mini Symbols::
|
|||
|
* typedef asymbol::
|
|||
|
* symbol handling functions::
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Reading Symbols, Next: Writing Symbols, Prev: Symbols, Up: Symbols
|
|||
|
|
|||
|
Reading symbols
|
|||
|
---------------
|
|||
|
|
|||
|
There are two stages to reading a symbol table from a BFD:
|
|||
|
allocating storage, and the actual reading process. This is an excerpt
|
|||
|
from an application which reads the symbol table:
|
|||
|
|
|||
|
long storage_needed;
|
|||
|
asymbol **symbol_table;
|
|||
|
long number_of_symbols;
|
|||
|
long i;
|
|||
|
|
|||
|
storage_needed = bfd_get_symtab_upper_bound (abfd);
|
|||
|
|
|||
|
if (storage_needed < 0)
|
|||
|
FAIL
|
|||
|
|
|||
|
if (storage_needed == 0) {
|
|||
|
return ;
|
|||
|
}
|
|||
|
symbol_table = (asymbol **) xmalloc (storage_needed);
|
|||
|
...
|
|||
|
number_of_symbols =
|
|||
|
bfd_canonicalize_symtab (abfd, symbol_table);
|
|||
|
|
|||
|
if (number_of_symbols < 0)
|
|||
|
FAIL
|
|||
|
|
|||
|
for (i = 0; i < number_of_symbols; i++) {
|
|||
|
process_symbol (symbol_table[i]);
|
|||
|
}
|
|||
|
|
|||
|
All storage for the symbols themselves is in an objalloc connected
|
|||
|
to the BFD; it is freed when the BFD is closed.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Writing Symbols, Next: Mini Symbols, Prev: Reading Symbols, Up: Symbols
|
|||
|
|
|||
|
Writing symbols
|
|||
|
---------------
|
|||
|
|
|||
|
Writing of a symbol table is automatic when a BFD open for writing
|
|||
|
is closed. The application attaches a vector of pointers to pointers to
|
|||
|
symbols to the BFD being written, and fills in the symbol count. The
|
|||
|
close and cleanup code reads through the table provided and performs
|
|||
|
all the necessary operations. The BFD output code must always be
|
|||
|
provided with an "owned" symbol: one which has come from another BFD,
|
|||
|
or one which has been created using `bfd_make_empty_symbol'. Here is an
|
|||
|
example showing the creation of a symbol table with only one element:
|
|||
|
|
|||
|
#include "bfd.h"
|
|||
|
main()
|
|||
|
{
|
|||
|
bfd *abfd;
|
|||
|
asymbol *ptrs[2];
|
|||
|
asymbol *new;
|
|||
|
|
|||
|
abfd = bfd_openw("foo","a.out-sunos-big");
|
|||
|
bfd_set_format(abfd, bfd_object);
|
|||
|
new = bfd_make_empty_symbol(abfd);
|
|||
|
new->name = "dummy_symbol";
|
|||
|
new->section = bfd_make_section_old_way(abfd, ".text");
|
|||
|
new->flags = BSF_GLOBAL;
|
|||
|
new->value = 0x12345;
|
|||
|
|
|||
|
ptrs[0] = new;
|
|||
|
ptrs[1] = (asymbol *)0;
|
|||
|
|
|||
|
bfd_set_symtab(abfd, ptrs, 1);
|
|||
|
bfd_close(abfd);
|
|||
|
}
|
|||
|
|
|||
|
./makesym
|
|||
|
nm foo
|
|||
|
00012345 A dummy_symbol
|
|||
|
|
|||
|
Many formats cannot represent arbitary symbol information; for
|
|||
|
instance, the `a.out' object format does not allow an arbitary number
|
|||
|
of sections. A symbol pointing to a section which is not one of
|
|||
|
`.text', `.data' or `.bss' cannot be described.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Mini Symbols, Next: typedef asymbol, Prev: Writing Symbols, Up: Symbols
|
|||
|
|
|||
|
Mini Symbols
|
|||
|
------------
|
|||
|
|
|||
|
Mini symbols provide read-only access to the symbol table. They use
|
|||
|
less memory space, but require more time to access. They can be useful
|
|||
|
for tools like nm or objdump, which may have to handle symbol tables of
|
|||
|
extremely large executables.
|
|||
|
|
|||
|
The `bfd_read_minisymbols' function will read the symbols into
|
|||
|
memory in an internal form. It will return a `void *' pointer to a
|
|||
|
block of memory, a symbol count, and the size of each symbol. The
|
|||
|
pointer is allocated using `malloc', and should be freed by the caller
|
|||
|
when it is no longer needed.
|
|||
|
|
|||
|
The function `bfd_minisymbol_to_symbol' will take a pointer to a
|
|||
|
minisymbol, and a pointer to a structure returned by
|
|||
|
`bfd_make_empty_symbol', and return a `asymbol' structure. The return
|
|||
|
value may or may not be the same as the value from
|
|||
|
`bfd_make_empty_symbol' which was passed in.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: typedef asymbol, Next: symbol handling functions, Prev: Mini Symbols, Up: Symbols
|
|||
|
|
|||
|
typedef asymbol
|
|||
|
---------------
|
|||
|
|
|||
|
An `asymbol' has the form:
|
|||
|
|
|||
|
|
|||
|
typedef struct symbol_cache_entry
|
|||
|
{
|
|||
|
/* A pointer to the BFD which owns the symbol. This information
|
|||
|
is necessary so that a back end can work out what additional
|
|||
|
information (invisible to the application writer) is carried
|
|||
|
with the symbol.
|
|||
|
|
|||
|
This field is *almost* redundant, since you can use section->owner
|
|||
|
instead, except that some symbols point to the global sections
|
|||
|
bfd_{abs,com,und}_section. This could be fixed by making
|
|||
|
these globals be per-bfd (or per-target-flavor). FIXME. */
|
|||
|
|
|||
|
struct _bfd *the_bfd; /* Use bfd_asymbol_bfd(sym) to access this field. */
|
|||
|
|
|||
|
/* The text of the symbol. The name is left alone, and not copied; the
|
|||
|
application may not alter it. */
|
|||
|
CONST char *name;
|
|||
|
|
|||
|
/* The value of the symbol. This really should be a union of a
|
|||
|
numeric value with a pointer, since some flags indicate that
|
|||
|
a pointer to another symbol is stored here. */
|
|||
|
symvalue value;
|
|||
|
|
|||
|
/* Attributes of a symbol: */
|
|||
|
|
|||
|
#define BSF_NO_FLAGS 0x00
|
|||
|
|
|||
|
/* The symbol has local scope; `static' in `C'. The value
|
|||
|
is the offset into the section of the data. */
|
|||
|
#define BSF_LOCAL 0x01
|
|||
|
|
|||
|
/* The symbol has global scope; initialized data in `C'. The
|
|||
|
value is the offset into the section of the data. */
|
|||
|
#define BSF_GLOBAL 0x02
|
|||
|
|
|||
|
/* The symbol has global scope and is exported. The value is
|
|||
|
the offset into the section of the data. */
|
|||
|
#define BSF_EXPORT BSF_GLOBAL /* no real difference */
|
|||
|
|
|||
|
/* A normal C symbol would be one of:
|
|||
|
`BSF_LOCAL', `BSF_FORT_COMM', `BSF_UNDEFINED' or
|
|||
|
`BSF_GLOBAL' */
|
|||
|
|
|||
|
/* The symbol is a debugging record. The value has an arbitary
|
|||
|
meaning, unless BSF_DEBUGGING_RELOC is also set. */
|
|||
|
#define BSF_DEBUGGING 0x08
|
|||
|
|
|||
|
/* The symbol denotes a function entry point. Used in ELF,
|
|||
|
perhaps others someday. */
|
|||
|
#define BSF_FUNCTION 0x10
|
|||
|
|
|||
|
/* Used by the linker. */
|
|||
|
#define BSF_KEEP 0x20
|
|||
|
#define BSF_KEEP_G 0x40
|
|||
|
|
|||
|
/* A weak global symbol, overridable without warnings by
|
|||
|
a regular global symbol of the same name. */
|
|||
|
#define BSF_WEAK 0x80
|
|||
|
|
|||
|
/* This symbol was created to point to a section, e.g. ELF's
|
|||
|
STT_SECTION symbols. */
|
|||
|
#define BSF_SECTION_SYM 0x100
|
|||
|
|
|||
|
/* The symbol used to be a common symbol, but now it is
|
|||
|
allocated. */
|
|||
|
#define BSF_OLD_COMMON 0x200
|
|||
|
|
|||
|
/* The default value for common data. */
|
|||
|
#define BFD_FORT_COMM_DEFAULT_VALUE 0
|
|||
|
|
|||
|
/* In some files the type of a symbol sometimes alters its
|
|||
|
location in an output file - ie in coff a `ISFCN' symbol
|
|||
|
which is also `C_EXT' symbol appears where it was
|
|||
|
declared and not at the end of a section. This bit is set
|
|||
|
by the target BFD part to convey this information. */
|
|||
|
|
|||
|
#define BSF_NOT_AT_END 0x400
|
|||
|
|
|||
|
/* Signal that the symbol is the label of constructor section. */
|
|||
|
#define BSF_CONSTRUCTOR 0x800
|
|||
|
|
|||
|
/* Signal that the symbol is a warning symbol. The name is a
|
|||
|
warning. The name of the next symbol is the one to warn about;
|
|||
|
if a reference is made to a symbol with the same name as the next
|
|||
|
symbol, a warning is issued by the linker. */
|
|||
|
#define BSF_WARNING 0x1000
|
|||
|
|
|||
|
/* Signal that the symbol is indirect. This symbol is an indirect
|
|||
|
pointer to the symbol with the same name as the next symbol. */
|
|||
|
#define BSF_INDIRECT 0x2000
|
|||
|
|
|||
|
/* BSF_FILE marks symbols that contain a file name. This is used
|
|||
|
for ELF STT_FILE symbols. */
|
|||
|
#define BSF_FILE 0x4000
|
|||
|
|
|||
|
/* Symbol is from dynamic linking information. */
|
|||
|
#define BSF_DYNAMIC 0x8000
|
|||
|
|
|||
|
/* The symbol denotes a data object. Used in ELF, and perhaps
|
|||
|
others someday. */
|
|||
|
#define BSF_OBJECT 0x10000
|
|||
|
|
|||
|
/* This symbol is a debugging symbol. The value is the offset
|
|||
|
into the section of the data. BSF_DEBUGGING should be set
|
|||
|
as well. */
|
|||
|
#define BSF_DEBUGGING_RELOC 0x20000
|
|||
|
|
|||
|
flagword flags;
|
|||
|
|
|||
|
/* A pointer to the section to which this symbol is
|
|||
|
relative. This will always be non NULL, there are special
|
|||
|
sections for undefined and absolute symbols. */
|
|||
|
struct sec *section;
|
|||
|
|
|||
|
/* Back end special data. */
|
|||
|
union
|
|||
|
{
|
|||
|
PTR p;
|
|||
|
bfd_vma i;
|
|||
|
} udata;
|
|||
|
|
|||
|
} asymbol;
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: symbol handling functions, Prev: typedef asymbol, Up: Symbols
|
|||
|
|
|||
|
Symbol handling functions
|
|||
|
-------------------------
|
|||
|
|
|||
|
`bfd_get_symtab_upper_bound'
|
|||
|
............................
|
|||
|
|
|||
|
*Description*
|
|||
|
Return the number of bytes required to store a vector of pointers to
|
|||
|
`asymbols' for all the symbols in the BFD ABFD, including a terminal
|
|||
|
NULL pointer. If there are no symbols in the BFD, then return 0. If an
|
|||
|
error occurs, return -1.
|
|||
|
#define bfd_get_symtab_upper_bound(abfd) \
|
|||
|
BFD_SEND (abfd, _bfd_get_symtab_upper_bound, (abfd))
|
|||
|
|
|||
|
`bfd_is_local_label'
|
|||
|
....................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_is_local_label(bfd *abfd, asymbol *sym);
|
|||
|
*Description*
|
|||
|
Return true if the given symbol SYM in the BFD ABFD is a compiler
|
|||
|
generated local label, else return false.
|
|||
|
|
|||
|
`bfd_is_local_label_name'
|
|||
|
.........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_is_local_label_name(bfd *abfd, const char *name);
|
|||
|
*Description*
|
|||
|
Return true if a symbol with the name NAME in the BFD ABFD is a
|
|||
|
compiler generated local label, else return false. This just checks
|
|||
|
whether the name has the form of a local label.
|
|||
|
#define bfd_is_local_label_name(abfd, name) \
|
|||
|
BFD_SEND (abfd, _bfd_is_local_label_name, (abfd, name))
|
|||
|
|
|||
|
`bfd_canonicalize_symtab'
|
|||
|
.........................
|
|||
|
|
|||
|
*Description*
|
|||
|
Read the symbols from the BFD ABFD, and fills in the vector LOCATION
|
|||
|
with pointers to the symbols and a trailing NULL. Return the actual
|
|||
|
number of symbol pointers, not including the NULL.
|
|||
|
#define bfd_canonicalize_symtab(abfd, location) \
|
|||
|
BFD_SEND (abfd, _bfd_canonicalize_symtab,\
|
|||
|
(abfd, location))
|
|||
|
|
|||
|
`bfd_set_symtab'
|
|||
|
................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_set_symtab (bfd *abfd, asymbol **location, unsigned int count);
|
|||
|
*Description*
|
|||
|
Arrange that when the output BFD ABFD is closed, the table LOCATION of
|
|||
|
COUNT pointers to symbols will be written.
|
|||
|
|
|||
|
`bfd_print_symbol_vandf'
|
|||
|
........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
void bfd_print_symbol_vandf(PTR file, asymbol *symbol);
|
|||
|
*Description*
|
|||
|
Print the value and flags of the SYMBOL supplied to the stream FILE.
|
|||
|
|
|||
|
`bfd_make_empty_symbol'
|
|||
|
.......................
|
|||
|
|
|||
|
*Description*
|
|||
|
Create a new `asymbol' structure for the BFD ABFD and return a pointer
|
|||
|
to it.
|
|||
|
|
|||
|
This routine is necessary because each back end has private
|
|||
|
information surrounding the `asymbol'. Building your own `asymbol' and
|
|||
|
pointing to it will not create the private information, and will cause
|
|||
|
problems later on.
|
|||
|
#define bfd_make_empty_symbol(abfd) \
|
|||
|
BFD_SEND (abfd, _bfd_make_empty_symbol, (abfd))
|
|||
|
|
|||
|
`bfd_make_debug_symbol'
|
|||
|
.......................
|
|||
|
|
|||
|
*Description*
|
|||
|
Create a new `asymbol' structure for the BFD ABFD, to be used as a
|
|||
|
debugging symbol. Further details of its use have yet to be worked out.
|
|||
|
#define bfd_make_debug_symbol(abfd,ptr,size) \
|
|||
|
BFD_SEND (abfd, _bfd_make_debug_symbol, (abfd, ptr, size))
|
|||
|
|
|||
|
`bfd_decode_symclass'
|
|||
|
.....................
|
|||
|
|
|||
|
*Description*
|
|||
|
Return a character corresponding to the symbol class of SYMBOL, or '?'
|
|||
|
for an unknown class.
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
int bfd_decode_symclass(asymbol *symbol);
|
|||
|
|
|||
|
`bfd_is_undefined_symclass '
|
|||
|
............................
|
|||
|
|
|||
|
*Description*
|
|||
|
Returns non-zero if the class symbol returned by bfd_decode_symclass
|
|||
|
represents an undefined symbol. Returns zero otherwise.
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_is_undefined_symclass (int symclass);
|
|||
|
|
|||
|
`bfd_symbol_info'
|
|||
|
.................
|
|||
|
|
|||
|
*Description*
|
|||
|
Fill in the basic info about symbol that nm needs. Additional info may
|
|||
|
be added by the back-ends after calling this function.
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
void bfd_symbol_info(asymbol *symbol, symbol_info *ret);
|
|||
|
|
|||
|
`bfd_copy_private_symbol_data'
|
|||
|
..............................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_copy_private_symbol_data(bfd *ibfd, asymbol *isym, bfd *obfd, asymbol *osym);
|
|||
|
*Description*
|
|||
|
Copy private symbol information from ISYM in the BFD IBFD to the symbol
|
|||
|
OSYM in the BFD OBFD. Return `true' on success, `false' on error.
|
|||
|
Possible error returns are:
|
|||
|
|
|||
|
* `bfd_error_no_memory' - Not enough memory exists to create private
|
|||
|
data for OSEC.
|
|||
|
|
|||
|
#define bfd_copy_private_symbol_data(ibfd, isymbol, obfd, osymbol) \
|
|||
|
BFD_SEND (obfd, _bfd_copy_private_symbol_data, \
|
|||
|
(ibfd, isymbol, obfd, osymbol))
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Archives, Next: Formats, Prev: Symbols, Up: BFD front end
|
|||
|
|
|||
|
Archives
|
|||
|
========
|
|||
|
|
|||
|
*Description*
|
|||
|
An archive (or library) is just another BFD. It has a symbol table,
|
|||
|
although there's not much a user program will do with it.
|
|||
|
|
|||
|
The big difference between an archive BFD and an ordinary BFD is
|
|||
|
that the archive doesn't have sections. Instead it has a chain of BFDs
|
|||
|
that are considered its contents. These BFDs can be manipulated like
|
|||
|
any other. The BFDs contained in an archive opened for reading will
|
|||
|
all be opened for reading. You may put either input or output BFDs
|
|||
|
into an archive opened for output; they will be handled correctly when
|
|||
|
the archive is closed.
|
|||
|
|
|||
|
Use `bfd_openr_next_archived_file' to step through the contents of
|
|||
|
an archive opened for input. You don't have to read the entire archive
|
|||
|
if you don't want to! Read it until you find what you want.
|
|||
|
|
|||
|
Archive contents of output BFDs are chained through the `next'
|
|||
|
pointer in a BFD. The first one is findable through the `archive_head'
|
|||
|
slot of the archive. Set it with `bfd_set_archive_head' (q.v.). A
|
|||
|
given BFD may be in only one open output archive at a time.
|
|||
|
|
|||
|
As expected, the BFD archive code is more general than the archive
|
|||
|
code of any given environment. BFD archives may contain files of
|
|||
|
different formats (e.g., a.out and coff) and even different
|
|||
|
architectures. You may even place archives recursively into archives!
|
|||
|
|
|||
|
This can cause unexpected confusion, since some archive formats are
|
|||
|
more expressive than others. For instance, Intel COFF archives can
|
|||
|
preserve long filenames; SunOS a.out archives cannot. If you move a
|
|||
|
file from the first to the second format and back again, the filename
|
|||
|
may be truncated. Likewise, different a.out environments have different
|
|||
|
conventions as to how they truncate filenames, whether they preserve
|
|||
|
directory names in filenames, etc. When interoperating with native
|
|||
|
tools, be sure your files are homogeneous.
|
|||
|
|
|||
|
Beware: most of these formats do not react well to the presence of
|
|||
|
spaces in filenames. We do the best we can, but can't always handle
|
|||
|
this case due to restrictions in the format of archives. Many Unix
|
|||
|
utilities are braindead in regards to spaces and such in filenames
|
|||
|
anyway, so this shouldn't be much of a restriction.
|
|||
|
|
|||
|
Archives are supported in BFD in `archive.c'.
|
|||
|
|
|||
|
`bfd_get_next_mapent'
|
|||
|
.....................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
symindex bfd_get_next_mapent(bfd *abfd, symindex previous, carsym **sym);
|
|||
|
*Description*
|
|||
|
Step through archive ABFD's symbol table (if it has one). Successively
|
|||
|
update SYM with the next symbol's information, returning that symbol's
|
|||
|
(internal) index into the symbol table.
|
|||
|
|
|||
|
Supply `BFD_NO_MORE_SYMBOLS' as the PREVIOUS entry to get the first
|
|||
|
one; returns `BFD_NO_MORE_SYMBOLS' when you've already got the last one.
|
|||
|
|
|||
|
A `carsym' is a canonical archive symbol. The only user-visible
|
|||
|
element is its name, a null-terminated string.
|
|||
|
|
|||
|
`bfd_set_archive_head'
|
|||
|
......................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_set_archive_head(bfd *output, bfd *new_head);
|
|||
|
*Description*
|
|||
|
Set the head of the chain of BFDs contained in the archive OUTPUT to
|
|||
|
NEW_HEAD.
|
|||
|
|
|||
|
`bfd_openr_next_archived_file'
|
|||
|
..............................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
bfd *bfd_openr_next_archived_file(bfd *archive, bfd *previous);
|
|||
|
*Description*
|
|||
|
Provided a BFD, ARCHIVE, containing an archive and NULL, open an input
|
|||
|
BFD on the first contained element and returns that. Subsequent calls
|
|||
|
should pass the archive and the previous return value to return a
|
|||
|
created BFD to the next contained element. NULL is returned when there
|
|||
|
are no more.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Formats, Next: Relocations, Prev: Archives, Up: BFD front end
|
|||
|
|
|||
|
File formats
|
|||
|
============
|
|||
|
|
|||
|
A format is a BFD concept of high level file contents type. The
|
|||
|
formats supported by BFD are:
|
|||
|
|
|||
|
* `bfd_object'
|
|||
|
The BFD may contain data, symbols, relocations and debug info.
|
|||
|
|
|||
|
* `bfd_archive'
|
|||
|
The BFD contains other BFDs and an optional index.
|
|||
|
|
|||
|
* `bfd_core'
|
|||
|
The BFD contains the result of an executable core dump.
|
|||
|
|
|||
|
`bfd_check_format'
|
|||
|
..................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_check_format(bfd *abfd, bfd_format format);
|
|||
|
*Description*
|
|||
|
Verify if the file attached to the BFD ABFD is compatible with the
|
|||
|
format FORMAT (i.e., one of `bfd_object', `bfd_archive' or `bfd_core').
|
|||
|
|
|||
|
If the BFD has been set to a specific target before the call, only
|
|||
|
the named target and format combination is checked. If the target has
|
|||
|
not been set, or has been set to `default', then all the known target
|
|||
|
backends is interrogated to determine a match. If the default target
|
|||
|
matches, it is used. If not, exactly one target must recognize the
|
|||
|
file, or an error results.
|
|||
|
|
|||
|
The function returns `true' on success, otherwise `false' with one
|
|||
|
of the following error codes:
|
|||
|
|
|||
|
* `bfd_error_invalid_operation' - if `format' is not one of
|
|||
|
`bfd_object', `bfd_archive' or `bfd_core'.
|
|||
|
|
|||
|
* `bfd_error_system_call' - if an error occured during a read - even
|
|||
|
some file mismatches can cause bfd_error_system_calls.
|
|||
|
|
|||
|
* `file_not_recognised' - none of the backends recognised the file
|
|||
|
format.
|
|||
|
|
|||
|
* `bfd_error_file_ambiguously_recognized' - more than one backend
|
|||
|
recognised the file format.
|
|||
|
|
|||
|
`bfd_check_format_matches'
|
|||
|
..........................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_check_format_matches(bfd *abfd, bfd_format format, char ***matching);
|
|||
|
*Description*
|
|||
|
Like `bfd_check_format', except when it returns false with `bfd_errno'
|
|||
|
set to `bfd_error_file_ambiguously_recognized'. In that case, if
|
|||
|
MATCHING is not NULL, it will be filled in with a NULL-terminated list
|
|||
|
of the names of the formats that matched, allocated with `malloc'.
|
|||
|
Then the user may choose a format and try again.
|
|||
|
|
|||
|
When done with the list that MATCHING points to, the caller should
|
|||
|
free it.
|
|||
|
|
|||
|
`bfd_set_format'
|
|||
|
................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
boolean bfd_set_format(bfd *abfd, bfd_format format);
|
|||
|
*Description*
|
|||
|
This function sets the file format of the BFD ABFD to the format
|
|||
|
FORMAT. If the target set in the BFD does not support the format
|
|||
|
requested, the format is invalid, or the BFD is not open for writing,
|
|||
|
then an error occurs.
|
|||
|
|
|||
|
`bfd_format_string'
|
|||
|
...................
|
|||
|
|
|||
|
*Synopsis*
|
|||
|
CONST char *bfd_format_string(bfd_format format);
|
|||
|
*Description*
|
|||
|
Return a pointer to a const string `invalid', `object', `archive',
|
|||
|
`core', or `unknown', depending upon the value of FORMAT.
|
|||
|
|
|||
|
|
|||
|
File: bfd.info, Node: Relocations, Next: Core Files, Prev: Formats, Up: BFD front end
|
|||
|
|
|||
|
Relocations
|
|||
|
===========
|
|||
|
|
|||
|
BFD maintains relocations in much the same way it maintains symbols:
|
|||
|
they are left alone until required, then read in en-masse and
|
|||
|
translated into an internal form. A common routine
|
|||
|
`bfd_perform_relocation' acts upon the canonical form to do the fixup.
|
|||
|
|
|||
|
Relocations are maintained on a per section basis, while symbols are
|
|||
|
maintained on a per BFD basis.
|
|||
|
|
|||
|
All that a back end has to do to fit the BFD interface is to create
|
|||
|
a `struct reloc_cache_entry' for each relocation in a particular
|
|||
|
section, and fill in the right bits of the structures.
|
|||
|
|
|||
|
* Menu:
|
|||
|
|
|||
|
* typedef arelent::
|
|||
|
* howto manager::
|
|||
|
|