uwx_find_symbol.3x (2010 09)

u
uwx_find_symbol(3X) uwx_find_symbol(3X)
(Integrity Systems Only)
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 rela-
tive 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 pro-
vided, 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 alloca-
tion.
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 relia-
bility 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.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1