77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
/*
|
|
* This file contains two functions that can be used to perform
|
|
* an EXEC call without the need for a "big" stack of MAX_ARG
|
|
* bytes. It is primarily used by the INIT module of the system.
|
|
*/
|
|
#include <lib.h>
|
|
#include <sys/types.h>
|
|
#include <unistd.h>
|
|
|
|
#define MAXSTK 256 /* maximum EXEC stack size */
|
|
#define PTRSIZE sizeof(char *)
|
|
|
|
_PROTOTYPE(int _execn,(char *name));
|
|
_PROTOTYPE(int _execnl,(char *name, char *arg0));
|
|
PRIVATE _PROTOTYPE(int _nexec,(char *name, char *argv[]));
|
|
|
|
PUBLIC int _execn(name)
|
|
char *name; /* pointer to file to be exec'd */
|
|
{
|
|
/* This funcion uses no arguments at all. */
|
|
PRIVATE char stack[3 * PTRSIZE];
|
|
|
|
return(_callm1(MM, EXEC, _len(name), sizeof(stack), 0, name, stack, NIL_PTR));
|
|
}
|
|
|
|
|
|
PUBLIC int _execnl(name, arg0)
|
|
char *name;
|
|
char *arg0;
|
|
{
|
|
/* This function resembles execl(2). */
|
|
|
|
return(_nexec(name, &arg0));
|
|
}
|
|
|
|
PRIVATE int _nexec(name, argv)
|
|
char *name; /* pointer to name of file to be executed */
|
|
char *argv[]; /* pointer to argument array */
|
|
{
|
|
char stack[MAXSTK];
|
|
char **argorg, *hp, **ap, *p;
|
|
int i, nargs, stackbytes, offset;
|
|
|
|
/* Count the argument pointers. */
|
|
nargs = 0;
|
|
argorg = argv;
|
|
while (*argorg++ != NIL_PTR) nargs++;
|
|
|
|
/* Prepare to set up the initial stack. */
|
|
hp = &stack[(nargs + 3) * PTRSIZE];
|
|
if (hp + nargs >= &stack[MAXSTK]) {
|
|
errno = E2BIG;
|
|
return(-1);
|
|
}
|
|
ap = (char **) stack;
|
|
*ap++ = (char *) nargs;
|
|
|
|
/* Prepare the argument pointers and strings. */
|
|
for (i = 0; i < nargs; i++) {
|
|
offset = hp - stack;
|
|
*ap++ = (char *) offset;
|
|
p = *argv++;
|
|
while (*p) {
|
|
*hp++ = *p++;
|
|
if (hp >= &stack[MAXSTK]) {
|
|
errno = E2BIG;
|
|
return(-1);
|
|
}
|
|
}
|
|
*hp++ = (char) 0;
|
|
}
|
|
*ap++ = NIL_PTR;
|
|
|
|
stackbytes = (((int) (hp - stack) + PTRSIZE - 1) / PTRSIZE) * PTRSIZE;
|
|
return(_callm1(MM, EXEC, _len(name), stackbytes, 0, name, stack, NIL_PTR));
|
|
}
|