NAME
uwx_find_symbol() — obtain symbolic information from ELF files
SYNOPSIS
#include <uwx.h>
int uwx_find_symbol(
struct uwx_env *env,
struct uwx_symbol_cache **cachep,
char *mod,
uint64_t relip,
char **funcp,
uint64_t *offsetp
);
DESCRIPTION
uwx_find_symbol()
is part of the Unwind Express Library for Integrity systems; see
uwx(3X).
uwx_find_symbol()
obtains symbolic information for a given IP (instruction pointer) from
the symbol tables in the ELF object file,
if available.
To use this interface, the name of the load module and the relative offset of the IP
from the beginning of that module's text segment must be known.
See
dlmodinfo(3C)
and
dlgetname(3C)
for information on obtaining information about load modules.
This entry point is provided for cases where an application may
wish to perform a quick stack unwind operation, saving only the IP
values in an array, then later produce a symbolic report.
It may also be used independently of any stack unwind operation
(note that an unwind environment object must be provided,
but it does not need to have a current context).
For obtaining source information while unwinding, see
uwx_get_sym_info(3X)
and
uwx_get_source_info(3X).
This entry point returns a subset of the information returned by
uwx_find_source_info().
Parameters
- env
A pointer to an unwind environment object.
The state of the unwind environment does not matter except that the
allocate and free callback routines are used for memory allocation.
- cachep
A pointer to a symbol cache pointer.
The symbol cache is an opaque object created and maintained
within the Unwind Express Library.
If
cachep
is NULL,
no symbol cache will be created.
If
cachep
is not NULL,
it must point to a pointer whose initial value is NULL.
uwx_find_symbol()
will create a symbol cache and store a pointer to the cache in
*cachep
for use on subsequent calls.
The cache can be released by calling
uwx_release_symbol_cache().
The symbol cache may be shared with
uwx_find_source_info().
- mod
The name of the load module.
This must be the name of an executable ELF object file
(a main program or a shared library).
- relip
The offset of the IP relative to the start of the load module's text segment.
If the offset of the start of the function is available, it may be used here
to improve the speed and reliability of the symbol lookup.
(The offset returned through the
offsetp
parameter would then be the difference between the symbol found
and the address passed in, which will usually be 0.)
- funcp
Pointer to a variable of type
char *
where the function name will be returned.
The returned function name is allocated within the unwind environment,
and the pointer is valid only until the next call to either
uwx_step()
or
uwx_free().
If NULL,
the function name will not be returned.
If the function name is not available, a NULL
pointer will be returned.
- offsetp
Pointer to a variable of type
uint64_t
where the function offset
(the difference between the IP and the actual value of the function symbol located)
will be returned.
If NULL,
the offset will not be returned.
If the function name is not available, an offset of 0 will be returned.
RETURN VALUE
uwx_find_symbol()
returns
UWX_OK
on success.
See
uwx(3X)
for error codes.
AUTHOR
The Unwind Express Library was developed by Hewlett-Packard.
SEE ALSO
dlgetname(3C),
dlmodinfo(3C),
uwx(3X),
uwx_add_to_bsp(3X),
uwx_find_source_info(3X),
uwx_free(3X),
uwx_get_abi_context_code(3X),
uwx_get_funcstart(3X),
uwx_get_module_info(3X),
uwx_get_nat(3X),
uwx_get_reg(3X),
uwx_get_source_info(3X),
uwx_get_sym_info(3X),
uwx_init(3X),
uwx_init_context(3X),
uwx_register_alloc_cb(3X),
uwx_register_callbacks(3X),
uwx_release_symbol_cache(3X),
uwx_self_do_context_frame(3X),
uwx_self_free_info(3X),
uwx_self_init_context(3X),
uwx_self_init_info(3X),
uwx_set_nofr(3X),
uwx_set_remote(3X),
uwx_step(3X),
uwx_step_inline(3X).
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