SunOS man pages : dlinfo (3)
Dynamic Linking Library Functions dlinfo(3DL)
NAME
dlinfo - dynamic load information
SYNOPSIS
cc [ flag ... ] file ... -ldl [ library ... ]
#include <dlfcn.h>
#include <link.h>
#include <limits.h>
int dlinfo(void *handle, int request, void *p);
DESCRIPTION
The dlinfo() function extracts information about a
dynamically-loaded object. This function is loosely modeled
after the ioctl() function. The request argument and a third
argument of varying type are passed to dlinfo(). The action
taken by dlinfo() depends on the value of the request pro-
vided.
A handle argument, required for all requests except
RTLD_DI_CONFIGADDR, is either the value returned from a dlo-
pen() or dlmopen() call, or the special handle RTLD_SELF. If
handle is the value returned from a dlopen() or dlmopen()
call, the information returned by the dlinfo() call pertains
to the specified object. If handle is the special handle
RTLD_SELF, the information returned by the dlinfo() call
pertains to the caller itself.
The following are possible values for request to be passed
into dlinfo():
RTLD_DI_CONFIGADDR
Obtain the configuration file name and the address at
which it has been loaded. The p argument is a Dl_info
pointer ( Dl_info *p). The following elements from
this structure are initialized:
dli_fname
The full name of the configuration file.
dli_fbase
The base address of the configuration file
loaded into memory.
RTLD_DI_LINKMAP
Obtain the Link_map for the handle specified. The p
argument points to a Link_map pointer ( Link_map **p
). The actual storage for the Link_map structure is
maintained by ld.so.1.
The Link_map structure includes the following members:
SunOS 5.8 Last change: 11 Aug 2000 1
Dynamic Linking Library Functions dlinfo(3DL)
unsigned long l_addr; /* base address */
char *l_name; /* object name */
Elf32_Dyn *l_ld; /* .dynamic section */
Link_map *l_next; /* next link object */
Link_map *l_prev; /* previous link object */
char *l_refname; /* filter reference name */
l_addr
The base address of the object loaded into
memory.
l_name
The full name of the loaded object. This is the
filename of the object as referenced by ld.so.1.
l_ld Points to the SHT_DYNAMIC structure.
l_next
The next Link_map on the link-map list, other
objects on the same link-map list as the current
object may be examined by following the and
l_prev fields.
l_prev
The previous Link_map on the link-map list.
l_refname
If the object referenced is a filter this field
points to the name of the object being filtered.
If the object is not a filter, this field will
be 0. See Linker and Libraries Guide.
RTLD_DI_LMID
Obtain the ID for the link-map list upon which the
handle is loaded. The p argument is a Lmid_t pointer (
Lmid_t *p).
RTLD_DI_SERINFO
Obtain the library search paths for the handle speci-
fied. The p argument is a Dl_serinfo pointer (
Dl_serinfo *p). A user must first initialize the
Dl_serinfo structure with a RTLD_DI_SERINFOSIZE
request. See EXAMPLES.
The returned Dl_serinfo structure contains dls_cnt
Dl_serpath entries. Each entry's dlp_name field points
to the search path. The corresponding dlp_info field
contains one of more flags indicating the origin of
the path (see the LA_SER_* flags defined in <link.h>).
SunOS 5.8 Last change: 11 Aug 2000 2
Dynamic Linking Library Functions dlinfo(3DL)
RTLD_DI_SERINFOSIZE
Initialize a Dl_serinfo structure for use in a
RTLD_DI_SERINFO request. Both the dls_cnt and dls_size
fields are returned to indicate the number of search
paths applicable to the handle, and the total size of
a Dl_serinfo buffer required to hold dls_cnt
Dl_serpath entries and the associated search path
strings.
To obtain the complete path information, a new
Dl_serinfo buffer of size dls_size should be allo-
cated, initialized with the dls_cnt and dls_size
entries, and passed to a RTLD_DI_SERINFO request. See
EXAMPLES.
RTLD_DI_ORIGIN
Obtain the origin of the dynamic object associated
with the handle. The p argument is a char pointer (
char *p). The dirname(3C) of the associated objects
realpath(3C), which can be no bigger than PATH_MAX, is
copied to the pointer p.
RETURN VALUES
If the request is invalid, the parameter p is null, handle
does not refer to a valid object opened by dlopen() or is
not the special handle RTLD_SELF, or the Dl_serinfo struc-
ture is uninitialized for a RTLD_DI_SERINFO request, then
dlinfo() returns -1. More detailed diagnostic information is
available through dlerror(3DL).
EXAMPLES
Example 1: Using dlinfo() to obtain the library search paths
The following example shows how a dynamic object can inspect
the library search paths that would be used to locate a sim-
ple filename with dlopen(). For simplicity, error checking
has been omitted.
Dl_serinfo _info, *info = &_info;
Dl_serpath *path
uint_t cnt;
/* determine search path count and required buffer size */
dlinfo(RTLD_SELF, RTLD_DI_SERINFOSIZE, (void *)info);
/* allocate new buffer and initialize */
info = malloc(_info.dls_size);
info->dls_size = _info.dls_size;
info->dls_cnt = _info.dls_cnt;
/* obtain sarch path information */
dlinfo(RTLD_SELF, RTLD_DI_SERINFO, (void *)info);
SunOS 5.8 Last change: 11 Aug 2000 3
Dynamic Linking Library Functions dlinfo(3DL)
path = &info->dls_serpath[0];
for (cnt = 1; cnt <= info->dls_cnt; cnt++, path++) {
(void) printf("%2d: %s\n", cnt, path->dls_name);
}
USAGE
The dlinfo() function is one of a family of functions that
give the user direct access to the dynamic linking facili-
ties (see Linker and Libraries Guide) and are available to
dynamically-linked processes only.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| MT-Level | MT-Safe |
|_____________________________|_____________________________|
SEE ALSO
ld(1), ioctl(2), dirname(3C), realpath(3C), dlclose(3DL),
dldump(3DL), dlerror(3DL), dlmopen(3DL), dlopen(3DL),
dlsym(3DL), attributes(5)
Linker and Libraries Guide
SunOS 5.8 Last change: 11 Aug 2000 4
|
 |
|
|
