dlmodadd.3c (2010 09)

d
dlmodadd(3C) dlmodadd(3C)
NAME
dlmodadd() - register information about dynamically generated functions
SYNOPSIS
cc [flag]... file...
-ldl [library ]...
#include <dlfcn.h>
void* dlmodadd(void* associate_handle,
void *func_start,
size_t func_size,
void *linkage_ptr,
void *unwind_info);
DESCRIPTION
dlmodadd() registers information about a dynamically generated function, which can be retrived
through dlmodinfo(). The dlmodremove()
interface can be used to remove the registered informa-
tion.
associate_handle is the module handle for an existing module with which the new function is associated.
When the dynamic loader is called from the new function, it will behave as if it had been called from the
associated module. This handle must be a handle returned by
dlopen() or dlget().
func_start is the starting address of the generated machine code for the function. It is NOT the address
of a function descriptor.
func_size is the size, in bytes, of the generated machine code.
linkage_ptr is the gp (global pointer) value to be used for the function. It could be the gp of the associated
module. It must be set to a valid value, even if the generated code doesn’t actually use gp, as it is
required at a minimum for following the personality routine pointer in the unwind information.
unwind_info is a pointer to the beginning of the unwind info block for the function. The unwind info
block contains the header word, unwind descriptors, personality routine pointer, and language-specific
data, as described in the Itanium-based system Software Conventions and Runtime Architecture docu-
ment.
When
dlmodadd() is invoked to register information about a dynamically generated function, the
dynamic loader creates an unwind header and a single-entry unwind table for the function. The unwind
header is associated with the address range occupied by the dynamically generated function. The dlmo-
dadd() routine returns a handle as identification of the newly-added function. Handles returned by
dlmodadd() share the same namespace as handles returned by dlopen() and dlget(), but they
may not be used in calls to dlclose() or dlsym().Ifdlmodinfo() is called with an ip_value that
belongs to a function that has been registered with
dlmodadd(), it returns the associate_handle
specified during dlmodadd() invocation. If a library is unloaded by dlclose(), the unwind info for
all dynamically generated functions associated with the library being unloaded is also removed.
MULTITHREAD USAGE
This routine is thread-safe.
RETURN VALUE
If successful,
dlmodadd() returns a handle as identification of the newly-added function. NULL is
returned otherwise.
ERRORS
If
dlmodadd() fails, a subsequent call to dlerrno() returns one of the following values:
[RTLD_ERR_NO_MEMORY] Out of memory.
[RTLD_ERR_CANT_APPLY_RELOC] Cannot apply relocation in library.
[RTLD_ERR_SIGINHIBIT_FAILED]
siginhibit failed on entry to dlmodadd().
[RTLD_ERR_SIGENABLE_FAILED]
sigenable failed on exit from dlmodadd().
[RTLD_ERR_INV_DLMODADD_ARGUMENT] Invalid
dlmodadd() argument .
[RTLD_ERR_SETCANCELSTATE_FAILED]
__thread_setcancelstate failed on entry to
or exit from dlmodadd().
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