st_dyn_start, st_dyn_next, st_dyn_count, st_dyn_find_tag,
st_dyn_tag, st_dyn_value, st_dyn_addr - Access routines
for dynamic header information in shared objects
#include <st.h>
st_status_t st_dyn_start(
st_obj_t *obj,
st_dynscn_t *pdyn ); st_status_t st_dyn_next(
st_obj_t *obj,
st_dynscn_t dcur,
st_dynscn_t *pdyn ); st_status_t st_dyn_count(
st_obj_t *obj,
unsigned int *pcount ); st_status_t
st_dyn_find_tag(
st_obj_t *obj,
unsigned int tag,
st_dynscn_t *pdyn ); st_status_t st_dyn_tag(
st_obj_t *obj,
st_dynscn_t dyn,
unsigned int *ptag ); st_status_t st_dyn_value(
st_obj_t *obj,
st_dynscn_t dyn,
unsigned long *pvalue ); st_status_t st_dyn_addr(
st_obj_t *obj,
st_dynscn_t dyn,
st_addr_t *addr );
Symbol Table and Object File Access Library (libst.a)
Specifies an object handle, as returned by the
st_obj_open() function. Specifies an address to which
st_dyn_start(), st_dyn_next(), or st_dyn_find_tag() return
a dynamic section handle. Specifies a dynamic section
handle as returned by st_dyn_start(), st_dyn_next(), or
st_dyn_find_tag() functions. Specifies an address to
which st_dyn_count() returns the number of entries in the
dynamic section. Specifies an address to which
st_dyn_tag() returns a dynamic section tag. Specifies a
dynamic section tag. Dynamic section tags are defined in
/usr/include/coff_dyn.h. The Object File/Symbol Table Format
Specification provides a complete description of all
dynamic section tags. Specifies an address to which
st_dyn_value() returns a dynamic section value. Dynamic
section values may be either link-time addresses or absolute
values. The dynamic section tag determines how the
associated dynamic section value should be interpreted.
The Object File/Symbol Table Format Specification identifies
value interpretations for all dynamic section tags.
Specifies an address to which st_dyn_addr() returns a
pointer to the data addressed by a dynamic section entry.
These functions are used to read dynamic section entries
in an object file. The dynamic section is an array of tag
and value pairs providing information that is used to navigate
and interpret additional dynamic load information
contained in the object file. The dynamic section entries
and other dynamic load information are described in the
Object File/Symbol Table Format Specification. This document
provides a complete list of dynamic section tags and
describes how each tag's corresponding value should be
interpreted. Used to iterate over all of the dynamic section
entries. These functions return an opaque dynamic
section handle to the pdyn parameter. You can use this
handle as an input argument in subsequent calls to other
dynamic section access functions. (To indicate that the
iteration over the dynamic sections has been completed,
st_dyn_next() returns NULL to the pdyn parameter.) This
function returns the number of entries in the specified
object's dynamic section to the pcount parameter. Used to
locate a dynamic section entry with a specific tag. This
function returns an opaque dynamic section handle to the
pdyn parameter. (To indicate that no matching dynamic section
entry was found, st_dyn_find_tag() returns NULL to
the pdyn parameter.) Used to read the components of a
dynamic section entry. The st_dyn_tag() function returns
the dynamic section entry tag to the ptag parameter. The
st_dyn_value() function returns the dynamic section entry
value to the pvalue parameter. The dynamic section entry
value may be a constant or a link-time address, or it may
be unused. If the specified dynamic section entry's value
is a link-time address, this function returns a corresponding
buffer pointer to the addr parameter. Otherwise,
NULL is returned to the addr parameter. The buffer pointer
can be used to access the file data that is referenced by
the dynamic section entry. The format of the data is
determined by the dynamic section entry tag.
All functions indicate success by returning a value of 0
(zero). A positive return value is an errno value from a
system call. A negative return value is a library error or
informational code. The library codes are documented in
st.h.
Return parameters are set to 0 when an error occurs. An
exception to this is the case in which an invalid input
parameter is passed. In such cases, the return parameters
will be unchanged. A non-zero return status is the recommended
method for detecting an error return from a libst
function.
The following program illustrates how to use libst routines
to read dynamic section data. This sample program
shows an algorithm for reading and displaying shared
library dependency information.
This example has been simplified for illustration purposes.
Return status should be tested after each function
call. See st_strerror(3) for an example of return status
testing.
#include "st.h" #include "coff_dyn.h"
main(int argc, char **argv){
st_status_t s; /* error status */
st_obj_t *obj; /* object handle */
st_dynscn_t pdyn; /* dynamic entry */
Coff_Lib *llib; /* library list */
int llibno; /* # of libraries */
char *dynstr; /* dynamic strings */
unsigned long val;
unsigned long addr;
int i;
s = st_obj_open(&obj, argv[1], ST_RDONLY);
/* Find dynamic section entry for the list of
* shared library dependencies.
*/
s = st_dyn_find_tag(obj, DT_LIBLIST, &pdyn);
if (!pdyn) {
printf("%s has no shared library dependencies\n",
argv[1]);
exit(0);
}
/* Get a pointer to the list of shared library
* dependencies.
*/
st_dyn_addr(obj, pdyn, &addr);
llib = (Coff_Lib *)addr;
/* Get the number of entries in the list. */
st_dyn_find_tag(obj, DT_LIBLISTNO, &pdyn);
st_dyn_value(obj, pdyn, &val);
llibno = val;
/* Get a pointer to the dynamic string table. */
st_dyn_find_tag(obj, DT_STRTAB, &pdyn);
st_dyn_addr(obj, pdyn, &addr);
dynstr = (char *)addr;
/* Print out the library dependency names. */
for (i = 0; i < llibno; i++) {
printf("%s\n", &dynstr[llib[i].l_name]);
} }
Header file that contains all definitions and function
prototypes for libst.a functions Header file that contains
definitions for dynamic section tag values
Functions: libst_intro(3), st_obj_open(3), st_str_error(3)
Programmer's Guide: Use a web browser such as netscape(1)
to access the Developers' Toolkit Supplement edition of
the Programmer's Guide at
file:/usr/share/doclib/dtk/guide/index.html
st_dyn_start(3)
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