Initial revision

mach/minixST/libsys/exec.c

@@ -0,0 +1,103 @@
+#include "lib.h"
+
+char *nullptr[1];		/* the EXEC calls need a zero pointer */
+
+#define	PTRSIZE	sizeof(char *)
+
+PUBLIC int execl(name, arg0)
+char *name;
+char *arg0;
+{
+  return execve(name, &arg0, nullptr);
+}
+
+PUBLIC int execle(name, argv)
+char *name, *argv;
+{
+  char **p;
+  p = (char **) &argv;
+  while (*p++) /* null statement */ ;
+  return execve(name, &argv, *p);
+}
+
+PUBLIC int execv(name, argv)
+char *name, *argv[];
+{
+  return execve(name, argv, nullptr);
+}
+
+
+PUBLIC int execve(name, argv, envp)
+char *name;			/* pointer to name of file to be executed */
+char *argv[];			/* pointer to argument array */
+char *envp[];			/* pointer to environment */
+{
+  char stack[MAX_ISTACK_BYTES];
+  char **argorg, **envorg, *hp, **ap, *p;
+  int i, nargs, nenvps, stackbytes, offset;
+  extern errno;
+
+  /* Count the argument pointers and environment pointers. */
+  nargs = 0;
+  nenvps = 0;
+  argorg = argv;
+  envorg = envp;
+  while (*argorg++ != NIL_PTR) nargs++;
+  while (*envorg++ != NIL_PTR) nenvps++;
+
+  /* Prepare to set up the initial stack. */
+  hp = &stack[(nargs + nenvps + 3) * PTRSIZE];
+  if (hp + nargs + nenvps >= &stack[MAX_ISTACK_BYTES]) {
+	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[MAX_ISTACK_BYTES]) {
+			errno = E2BIG;
+			return(-1);
+		}
+	}
+	*hp++ = (char) 0;
+  }
+  *ap++ = NIL_PTR;
+
+  /* Prepare the environment pointers and strings. */
+  for (i = 0; i < nenvps; i++) {
+	offset = hp - stack;
+	*ap++ = (char *) offset;
+	p = *envp++;
+	while (*p) {
+		*hp++ = *p++;
+		if (hp >= &stack[MAX_ISTACK_BYTES]) {
+			errno = E2BIG;
+			return(-1);
+		}
+	}
+	*hp++ = (char) 0;
+  }
+  *ap++ = NIL_PTR;
+  stackbytes = ( ( (int)(hp - stack) + PTRSIZE - 1)/PTRSIZE) * PTRSIZE;
+  return callm1(MM_PROC_NR, EXEC, len(name), stackbytes, 0,name, stack,NIL_PTR);
+}
+
+
+PUBLIC execn(name)
+char *name;			/* pointer to file to be exec'd */
+{
+/* Special version used when there are no args and no environment.  This call
+ * is principally used by INIT, to avoid having to allocate MAX_ISTACK_BYTES.
+ */
+
+  static char stack[3 * PTRSIZE];
+
+  return callm1(MM_PROC_NR, EXEC, len(name), sizeof(stack), 0, name, stack, NIL_PTR);
+}