NAME
dlmodinfo() — retrieve information about a loaded module (program or shared library)
SYNOPSIS
cc
[flag]...
file...
-ldl
[library]...
#include <dlfcn.h>
uint64_t dlmodinfo(uint64_t ip_value,
struct load_module_desc *desc,
size_t desc_size,
void *(*read_tgt_mem)(void* buffer,
uint64_t ptr,
size_t bufsiz,
int ident),
int ident_parm,
uint64_t load_map_parm);
Multithread Usage
Thread safe in
libdl.sl
but not in
libxpdl.sl.
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
contains the module info of
dld
itself.
desc
is a buffer of memory allocated by the user program. The dynamic loader
fills 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 uses 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 is 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
returns the value of its buffer parameter,
otherwise, it returns 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
uint64_t.
ERRORS
If
dlmodinfo()
fails, a subsequent call to
dlerrno()
returns one of the following values:
- RTLD_ERR_CANT_APPLY_RELOC
Cannot apply relocation in library.
- RTLD_ERR_INV_ADDRESS
Invalid address.
- RTLD_ERR_INV_BUFFER_ARGUMENT
Invalid descriptor argument
- RTLD_ERR_INV_DESC_VERSION
Invalid descriptor version.
- RTLD_ERR_NO_MEMORY
Out of memory.
- RTLD_ERR_READ_TGT_MEM_FAILED
read_tgt_mem
failed in reading target memory.
- RTLD_ERR_SETCANCELSTATE_FAILED
__thread_setcancelstate
failed on entry to or exit from
dlmodinfo().
- RTLD_ERR_SIGENABLE_FAILED
sigenable
failed on exit from
dlmodinfo().
- RTLD_ERR_SIGINHIBIT_FAILED
siginhibit
failed on entry to
dlmodinfo().
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)
Returns the last error message recorded by
dld.
- dlerrno(3C)
Returns an error code for the last error 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)
Printable version
