st_dyn_start(3)st_dyn_start(3)NAME
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 informa‐
tion in shared objects
SYNOPSIS
#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 );
LIBRARY
Symbol Table and Object File Access Library (libst.a)
PARAMETERS
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 Speci‐
fication 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 Ta‐
ble 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.
DESCRIPTION
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 com‐
plete list of dynamic section tags and describes how each tag's corre‐
sponding value should be interpreted. Used to iterate over all of the
dynamic section entries. These functions return an opaque dynamic sec‐
tion 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 com‐
pleted, st_dyn_next() returns NULL to the pdyn parameter.) This func‐
tion 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 sec‐
tion 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 param‐
eter. 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.
RETURN VALUES
All functions indicate success by returning a value of 0 (zero). A pos‐
itive 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.
EXAMPLES
The following program illustrates how to use libst routines to read
dynamic section data. This sample program shows an algorithm for read‐
ing and displaying shared library dependency information.
This example has been simplified for illustration purposes. Return sta‐
tus 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]);
} }
FILES
Header file that contains all definitions and function prototypes for
libst.a functions Header file that contains definitions for dynamic
section tag values
SEE ALSO
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)
