ossp-pkg/js/src/jsdso.c
1.1
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/* ATTENTION: This is an OSSP js extension to the Mozilla JavaScript engine.
It was implemented by Ralf S. Engelschall <rse@engelschall.com> for OSSP. */
#if defined(OSSP) && defined(JS_HAS_DSO_OBJECT) && JS_HAS_DSO_OBJECT
/* own headers (part 1/2) */
#include "jsstddef.h"
/* system headers */
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
/* own headers (part 2/2) */
#include "jstypes.h"
#include "jsapi.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsconfig.h"
#include "jsobj.h"
#include "jsdso.h"
/* process local storage of DSO handles */
static void *dso_handle[10000];
/* type of the DSO load/unload functions */
typedef JSBool (*dso_func_t)(JSContext *cx);
/* ISO-C type coersion trick */
typedef union { void *vp; dso_func_t fp; } dso_func_ptr_t;
/* public C API function: DSO loading */
JS_PUBLIC_API(JSBool)
JS_DSOLoad(JSContext *cx, int *idp, const char *filename)
{
int id;
void *handle;
dso_func_ptr_t func;
JSBool rc;
/* determine next free DSO handle slot */
for (id = 0; dso_handle[id] != NULL && id < sizeof(dso_handle)/sizeof(dso_handle[0]); id++)
;
if (id == sizeof(dso_handle)/sizeof(dso_handle[0])) {
JS_ReportError(cx, "no more free DSO handle slots available");
return JS_FALSE;
}
/* load DSO into process */
if ((handle = dlopen(filename, RTLD_NOW)) == NULL) {
JS_ReportError(cx, "unable to load DSO \"%s\": %s", filename, dlerror());
return JS_FALSE;
}
/* resolve "js_DSO_load" function, call it and insist on a true return */
if ((func.vp = dlsym(handle, "js_DSO_load")) == NULL) {
JS_ReportError(cx, "unable to resolve symbol \"js_DSO_load\" in DSO \"%s\"", filename);
dlclose(handle);
return JS_FALSE;
}
rc = func.fp(cx);
if (!rc) {
JS_ReportError(cx, "function \"js_DSO_load\" in DSO \"%s\" returned error", filename);
dlclose(handle);
return JS_FALSE;
}
/* store DSO handle into process local storage */
dso_handle[id] = handle;
/* return DSO id to caller */
if (idp != NULL)
*idp = id;
return JS_TRUE;
}
/* public C API function: DSO unloading */
JS_PUBLIC_API(JSBool)
JS_DSOUnload(JSContext *cx, int id)
{
int idx;
void *handle;
dso_func_ptr_t func;
JSBool rc;
/* sanity check DSO id */
if (id < 0 || id >= sizeof(dso_handle)/sizeof(dso_handle[0])) {
JS_ReportError(cx, "invalid argument: DSO id #%d out of range", id);
return JS_FALSE;
}
/* determine DSO handle */
if ((handle = dso_handle[id]) == NULL) {
JS_ReportError(cx, "invalid argument: DSO id #%d currently unused", id);
return JS_FALSE;
}
/* resolve "js_DSO_unload" function and (if available only)
call it and insist on a true return */
if ((func.vp = dlsym(handle, "js_DSO_unload")) != NULL) {
rc = func.fp(cx);
if (!rc) {
JS_ReportError(cx, "function \"js_DSO_unload\" in DSO with id #%d returned error", idx);
return JS_FALSE;
}
}
/* unload DSO from process */
dlclose(handle);
/* free DSO handle slot */
dso_handle[id] = NULL;
return JS_TRUE;
}
/* global JavaScript language DSO object method: id = DSO.load("filename.so") */
static JSBool dso_load(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
JSString *filename;
char *c_filename;
int id;
/* usage sanity checks */
if (argc == 0) {
JS_ReportError(cx, "usage: id = DSO.load(filename)");
return JS_FALSE;
}
if (argc != 1) {
JS_ReportError(cx, "invalid number of arguments: %d received, %d expected", argc, 1);
return JS_FALSE;
}
/* determine filename */
if ((filename = js_ValueToString(cx, argv[0])) == NULL) {
JS_ReportError(cx, "invalid argument");
return JS_FALSE;
}
if ((c_filename = JS_GetStringBytes(filename)) == NULL) {
JS_ReportError(cx, "invalid argument");
return JS_FALSE;
}
/* load DSO */
if (!JS_DSOLoad(cx, &id, c_filename))
return JS_FALSE;
/* return DSO handle id */
*rval = INT_TO_JSVAL(id);
return JS_TRUE;
}
/* global JavaScript language DSO object method: DSO.unload(id) */
static JSBool dso_unload(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
{
int id;
JSBool rc;
/* usage sanity checks */
if (argc == 0) {
JS_ReportError(cx, "usage: DSO.unload(id)");
return JS_FALSE;
}
if (argc != 1) {
JS_ReportError(cx, "invalid number of arguments: %d received, %d expected", argc, 1);
return JS_FALSE;
}
/* determine DSO id */
id = JSVAL_TO_INT(argv[0]);
/* unload DSO */
if (!JS_DSOUnload(cx, id))
return JS_FALSE;
return JS_TRUE;
}
/* JavaScript DSO class method definitions */
static JSFunctionSpec dso_methods[] = {
{ "load", dso_load, 1, 0, 0 },
{ "unload", dso_unload, 1, 0, 0 },
{ NULL, NULL, 0, 0, 0 }
};
/* JavaScript DSO class definition */
static JSClass dso_class = {
"DSO",
0,
JS_PropertyStub,
JS_PropertyStub,
JS_PropertyStub,
JS_PropertyStub,
JS_EnumerateStub,
JS_ResolveStub,
JS_ConvertStub,
JS_FinalizeStub,
JSCLASS_NO_OPTIONAL_MEMBERS
};
/* JavaScript DSO class global initializer */
JSObject *js_InitDSOClass(JSContext *cx, JSObject *obj)
{
JSObject *DSO;
if ((DSO = JS_DefineObject(cx, obj, "DSO", &dso_class, NULL, 0)) == NULL)
return NULL;
if (!JS_DefineFunctions(cx, DSO, dso_methods))
return NULL;
return DSO;
}
#endif /* JS_HAS_DSO_OBJECT */
