NAME
dlmodinfo — retrieve information about a loaded module (program or shared library)
SYNOPSIS
cc
[flag ... ]
file ...
-ldl
[library] ...
#include <dlfcn.h>
unsigned long dlmodinfo(unsigned long ip_value,
struct load_module_desc *desc,
size_t desc_size,
void *(*read_tgt_mem)(void* buffer,
unsigned long ptr,
size_t bufsiz,
int ident),
int ident_parm,
uint64_t load_map_parm);
DESCRIPTION
dlmodinfo
is one of a family of routines that give the user
direct access to the dynamic linking facilities.
dlmodinfo
retrieves information about a loaded module from a given address value.
dlmodinfo()
searches all currently loaded load modules looking for a load module
whose address range (address range of all loaded segments) holds the
given address value. The
dlmodinfo
routine fills the
load_module_desc
with information from the matching load module.
ip_value
is the instruction pointer value of the requested library. If the value is
NULL, then
desc
will contain the module info of dld itself.
desc
is a buffer of memory allocated by the user program. The dynamic loader will
fill this in with module information.
desc_size
is the size in bytes of the
desc
buffer.
read_tgt_mem
is a pointer to a function used by
dlmodinfo
to retrieve needed information. If the value is NULL, the dynamic loader
will use its own internal data structures to find the correct load module
and the following two parameters are ignored.
- ident_parm
Is only used to pass the fourth parameter to
read_tgt_mem.
- load_map_parm
Is only used when calling through
read_tgt_mem.
It contains the starting address of the load map.
Otherwise, the function pointer will be used to read memory during its search,
using these parameters:
- buffer
a buffer supplied by
dlmodinfo
to read into
- ptr
the virtual memory address to read from
- bufsiz
the size of buffer in bytes
- ident
the value of the ident_parm parameter to
dlmodinfo
On success,
read_tgt_mem
will return the value of its buffer parameter,
otherwise, it will return NULL.
read_tgt_mem
allows
dlmodinfo
to find a load module in one process on behalf of another. The calling
process passes a callback via
read_tgt_mem
in order to read memory in a different process address space from the one
in which
dlmodinfo
resides.
ip_value,
load_map_parm,
and
ptr
from
read_tgt_mem
can be pointers to objects in another process. For example, when a 32 bit
program wants to enquire about a 64 bit program, the
ip_value
and
load_map_parm
should be 64 bit values. Any 32 bit pointers should be typecasted to 64 bits
by the user program when passed in the
ip_value
or
load_map_parm
parameters.
If the calling process calls
dlmodinfo
with a callback registered via
read_tgt_mem,
it must supply the starting address of the target process' load map in the
load_map_parm
parameter to
dlmodinfo.
This can be retrieved by using the
DT_HP_LOAD_MAP
dynamic table entry in the target program file.
A cross-process load module operation can be done via
dlmodinfo,
for example, by issuing a call to ttrace().
RETURN VALUE
If successful,
dlmodinfo
returns a handle for the shared library as defined by the return value from
dlopen().
NULL is returned otherwise.
The return values are type-converted to
unsigned
long.
MULTITHREAD USAGE
Thread safe in
libdl.sl
but not in
libxpdl.sl.
AUTHOR
dlmodinfo
was developed by HP.
SEE ALSO
Miscellaneous:
- a.out(4)
Assembler, compiler, and linker output.
- dlclose(3C)
Unloads a shared library previously loaded by
dlopen().
- dlerror(3C)
Prints the last error message recorded by
dld.
- dlget(3C)
Returns information about a loaded module.
- dlgetname(3C)
Returns the name of the storage containing a load module.
- dlopen(3C)
Loads a shared library.
- dlsym(3C)
Gets the address of a symbol in a shared library.
Texts and Tutorials:
- HP-UX Linker and Libraries Online User Guide
(See the
+help
option)
- HP-UX Linker and Libraries User's Guide
(See
manuals(5)
for ordering information)
