New installation mechanism, updated to 1.5

mach/minix/libsys/_execnl.c

@@ -0,0 +1,75 @@
+/*
+ * 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>
+
+#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));
+}