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uwx_find_source_info(3X)

Integrity Systems Only
HP-UX 11i Version 3: February 2007
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NAME

uwx_find_source_info() — obtain source information from ELF files

SYNOPSIS

#include <uwx.h> int uwx_find_source_info( struct uwx_env *env, struct uwx_symbol_cache **cachep, char *mod, uint64_t relip, uint64_t relfuncstart, int inline_context, char **ifuncp, char **funcp, uint64_t *offsetp, char **srcfilep, int *linenump, int *inline_contextp );

DESCRIPTION

uwx_find_source_info() is part of the Unwind Express Library for Integrity systems; see uwx(3X). uwx_find_source_info() obtains source file and line number information for a given IP (instruction pointer) from the symbolic information stored 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).

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_source_info() 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_symbol().

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.

relfuncstart

The offset of the start of the function containing the IP, relative to the start of the load module's text segment. If the function start address is not known, the relip can be passed instead. (The advantage of knowing the function start address is that symbol lookup can be faster and more reliable.)

inline_context

The value of the inline context identifier. This should be 0 except when stepping through inlined calls.

ifuncp

Pointer to a variable of type char * where the inlined function name will be returned. If NULL, the inlined function name will not be returned. If the IP of the current context is not in an inlined call or if symbolic debug information is not available, a NULL pointer will be returned.

funcp

Pointer to a variable of type char * where the function name will be returned. 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 will be returned (the difference between the IP and the actual value of the function symbol located). If NULL, the offset will not be returned. If the function name is not available, an offset of 0 will be returned.

srcfilep

Pointer to a variable of type char * where the source file name will be returned. If NULL, the source file name will not be returned. If symbolic debug information is not available, a NULL pointer will be returned.

linenump

Pointer to a variable of type int where the source line number will be returned. If NULL, the source line number will not be returned. If symbolic debug information is not available, 0 will be returned.

inline_contextp

Pointer to a variable of type int where the inline context identifier will be returned. If NULL, the inline context identifier will not be returned. If the IP of the current context is not in an inlined call or if symbolic debug information is not available, 0 will be returned.

In all cases where a pointer to a string is returned, the string is allocated within the unwind environment, and the pointer is valid only until the next call to either uwx_step() or uwx_free().

Stepping through inlined calls

If uwx_find_source_info() returns a non-zero inline context identifier, it indicates that the IP is located within an inline call. If the application wishes to step through the chain of inlined calls, it can find the name of the inlined function through the ifuncp pointer, then call uwx_find_source_info() again, this time passing the previously-returned value of the inline context identifier as the inline_context parameter. This process should be repeated until the returned identifier is 0.

RETURN VALUE

uwx_find_source_info() returns UWX_OK on success. See uwx(3X) for error codes.

AUTHOR

The Unwind Express Library was developed by Hewlett-Packard.

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