rc

commit 2ea901dfe7f367ddad61b3a64bbef4195a90ce35
parent f8f33b2674afaa2682c4a4ccec3e20439c53c144
Author: tim <tim>
Date:   Tue, 20 May 1997 16:17:15 +0000

Initial revision

Diffstat:
A
exec.c
 | 
130
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 130 insertions(+), 0 deletions(-)
diff --git a/exec.c b/exec.c
@@ -0,0 +1,130 @@
+/* exec.c */
+#include <signal.h>
+#include <errno.h>
+#include <setjmp.h>
+#include "rc.h"
+#include "jbwrap.h"
+
+/*
+   Takes an argument list and does the appropriate thing (calls a
+   builtin, calls a function, etc.)
+*/
+
+extern void exec(List *s, bool parent) {
+	char **av, **ev = NULL;
+	int pid, stat;
+	builtin_t *b;
+	char *path = NULL;
+	bool didfork, returning, saw_exec, saw_builtin;
+	av = list2array(s, dashex);
+	saw_builtin = saw_exec = FALSE;
+	do {
+		if (*av == NULL	|| isabsolute(*av))
+			b = NULL;
+		else if (!saw_builtin && fnlookup(*av) != NULL)
+			b = funcall;
+		else
+			b = isbuiltin(*av);
+
+		/*
+		   a builtin applies only to the immmediately following
+		   command, e.g., builtin exec echo hi
+		*/
+		saw_builtin = FALSE;
+
+		if (b == b_exec) {
+			av++;
+			saw_exec = TRUE;
+			parent = FALSE;
+		} else if (b == b_builtin) {
+			av++;
+			saw_builtin = TRUE;
+		}
+	} while (b == b_exec || b == b_builtin);
+	if (*av == NULL && saw_exec) { /* do redirs and return on a null exec */
+		doredirs();
+		return;
+	}
+	/* force an exit on exec with any rc_error, but not for null commands as above */
+	if (saw_exec)
+		rc_pid = -1;
+	if (b == NULL) {
+		path = which(*av, TRUE);
+		if (path == NULL && *av != NULL) { /* perform null commands for redirections */
+			set(FALSE);
+			redirq = NULL;
+			if (parent)
+				return;
+			rc_exit(1);
+		}
+		ev = makeenv(); /* environment only needs to be built for execve() */
+	}
+	/*
+	   If parent & the redirq is nonnull, builtin or not it has to fork.
+	   If the fifoq is nonnull, then it must be emptied at the end so we
+	   must fork no matter what.
+	 */
+	if ((parent && (b == NULL || redirq != NULL)) || outstanding_cmdarg()) {
+		pid = rc_fork();
+		didfork = TRUE;
+	} else {
+		pid = 0;
+		didfork = FALSE;
+	}
+	returning = (!didfork && parent);
+	switch (pid) {
+	case -1:
+		uerror("fork");
+		rc_error(NULL);
+		/* NOTREACHED */
+	case 0:
+		if (!returning)
+			setsigdefaults(FALSE);
+		pop_cmdarg(FALSE);
+		doredirs();
+
+		/* null commands performed for redirections */
+		if (*av == NULL || b != NULL) {
+			if (b != NULL)
+				(*b)(av);
+			if (returning)
+				return;
+			rc_exit(getstatus());
+		}
+#ifdef NOEXECVE
+		my_execve(path, (const char **) av, (const char **) ev); /* bogus, huh? */
+#else
+		execve(path, (const char **) av, (const char **) ev);
+#endif
+#ifdef DEFAULTINTERP
+		if (errno == ENOEXEC) {
+			*av = path;
+			*--av = DEFAULTINTERP;
+			execve(*av, (const char **) av, (const char **) ev);
+		}
+#endif
+		uerror(*av);
+		rc_exit(1);
+		/* NOTREACHED */
+	default:
+		redirq = NULL;
+		rc_wait4(pid, &stat, TRUE);
+		setstatus(-1, stat);
+		/*
+		   There is a very good reason for having this weird
+		   nl_on_intr variable: when rc and its child both
+		   process a SIGINT, (i.e., the child has a SIGINT
+		   catcher installed) then you don't want rc to print
+		   a newline when the child finally exits. Here's an
+		   example: ed, <type ^C>, <type "q">. rc does not
+		   and should not print a newline before the next
+		   prompt, even though there's a SIGINT in its signal
+		   vector.
+		*/
+		if ((stat & 0xff) == 0)
+			nl_on_intr = FALSE;
+		sigchk();
+		nl_on_intr = TRUE;
+		pop_cmdarg(TRUE);
+	}
+}