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/*
* File: fload.r
* Contents: loadfunc.
*
* This file contains loadfunc(), the dynamic loading function for
* Unix systems having the <dlfcn.h> interface.
*
* from Icon:
* p := loadfunc(filename, funcname)
* p(arg1, arg2, ...)
*
* in C:
* int func(int argc, dptr argv)
* return -1 for failure, 0 for success, >0 for error
* argc is number of true args not including argv[0]
* argv[0] is for return value; others are true args
*/
#ifdef LoadFunc
#ifndef RTLD_LAZY /* normally from <dlfcn.h> */
#define RTLD_LAZY 1
#endif /* RTLD_LAZY */
int glue();
int makefunc (dptr d, char *name, int (*func)());
"loadfunc(filename,funcname) - load C function dynamically."
function{0,1} loadfunc(filename,funcname)
if !cnv:C_string(filename) then
runerr(103, filename)
if !cnv:C_string(funcname) then
runerr(103, funcname)
abstract {
return proc
}
body
{
int (*func)();
static char *curfile;
static void *handle;
char *funcname2;
/*
* Get a library handle, reusing it over successive calls.
*/
if (!handle || !curfile || strcmp(filename, curfile) != 0) {
if (curfile)
free((pointer)curfile); /* free the old file name */
curfile = salloc(filename); /* save the new name */
handle = dlopen(filename, RTLD_LAZY | RTLD_GLOBAL); /* get handle */
}
/*
* Load the function. Diagnose both library and function errors here.
*/
if (handle) {
func = (int (*)())dlsym(handle, funcname);
if (!func) {
/*
* If no function, try again by prepending an underscore.
* (for OpenBSD and similar systems.)
*/
funcname2 = malloc(strlen(funcname) + 2);
if (funcname2) {
*funcname2 = '_';
strcpy(funcname2 + 1, funcname);
func = (int (*)())dlsym(handle, funcname2);
free(funcname2);
}
}
}
if (!handle || !func) {
fprintf(stderr, "\nloadfunc(\"%s\",\"%s\"): %s\n",
filename, funcname, dlerror());
runerr(216);
}
/*
* Build and return a proc descriptor.
*/
if (!makefunc(&result, funcname, func))
runerr(305);
return result;
}
end
/*
* makefunc(d, name, func) -- make function descriptor in d.
*
* Returns 0 if memory could not be allocated.
*/
int makefunc(d, name, func)
dptr d;
char *name;
int (*func)();
{
struct b_proc *blk;
blk = (struct b_proc *)malloc(sizeof(struct b_proc));
if (!blk)
return 0;
blk->title = T_Proc;
blk->blksize = sizeof(struct b_proc);
blk->entryp.ccode = glue; /* set code addr to glue routine */
blk->nparam = -1; /* varargs flag */
blk->ndynam = -1; /* treat as built-in function */
blk->nstatic = 0;
blk->fstatic = 0;
blk->pname.dword = strlen(name);
blk->pname.vword.sptr = salloc(name);
blk->lnames[0].dword = 0;
blk->lnames[0].vword.sptr = (char *)func;
/* save func addr in lnames[0] vword */
d->dword = D_Proc; /* build proc descriptor */
d->vword.bptr = (union block *)blk;
return 1;
}
/*
* This glue routine is called when a loaded function is invoked.
* It digs the actual C code address out of the proc block, and calls that.
*/
int glue(argc, dargv)
int argc;
dptr dargv;
{
int status, (*func)();
struct b_proc *blk;
struct descrip r;
tended struct descrip p;
blk = (struct b_proc *)dargv[0].vword.bptr; /* proc block address */
func = (int (*)())blk->lnames[0].vword.sptr; /* entry point address */
p = dargv[0]; /* save proc for traceback */
dargv[0] = nulldesc; /* set default return value */
status = (*func)(argc, dargv); /* call func */
if (status == 0)
Return; /* success */
if (status < 0)
Fail; /* failure */
r = dargv[0]; /* save result value */
dargv[0] = p; /* restore proc for traceback */
if (is:null(r))
RunErr(status, NULL); /* error, no value */
RunErr(status, &r); /* error, with value */
}
#endif /* LoadFunc */
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