From e5888a1ffdae813d7575f5fb02275c6bb07e5199 Mon Sep 17 00:00:00 2001
From: Taru Karttunen <taruti@taruti.net>
Date: Wed, 30 Mar 2011 15:46:40 +0300
Subject: Import sources from 2011-03-30 iso image

---
 sys/src/cmd/lock.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100755 sys/src/cmd/lock.c

(limited to 'sys/src/cmd/lock.c')

diff --git a/sys/src/cmd/lock.c b/sys/src/cmd/lock.c
new file mode 100755
index 000000000..1b2197f0d
--- /dev/null
+++ b/sys/src/cmd/lock.c
@@ -0,0 +1,168 @@
+/*
+ * lock - keep a lock alive while a command runs
+ */
+
+#include <u.h>
+#include <libc.h>
+#include <ctype.h>
+
+static int debug;
+static int lockwait;
+
+void	error(char*);
+void	notifyf(void*, char*);
+
+static void
+usage(void)
+{
+	fprint(2, "usage: %s [-dw] lock [command [file]...]\n", argv0);
+	exits("usage");
+}
+
+static Waitmsg *
+waitfor(int pid)
+{
+	char err[ERRMAX];
+	Waitmsg *w;
+
+	for (;;) {
+		w = wait();
+		if (w == nil){
+			errstr(err, sizeof err);
+			if(strcmp(err, "interrupted") == 0)
+				continue;
+			return nil;
+		}
+		if (w->pid == pid)
+			return w;
+	}
+}
+
+static int
+openlock(char *lock)
+{
+	int lckfd;
+	Dir *dir;
+
+	if (lockwait)
+		while ((lckfd = open(lock, ORDWR)) < 0)
+			sleep(1000);
+	else
+		lckfd = open(lock, ORDWR);
+	if (lckfd < 0)
+		sysfatal("can't open %s read/write: %r", lock);
+	dir = dirfstat(lckfd);
+	if (dir == nil)
+		sysfatal("can't fstat %s: %r", lock);
+	if (!(dir->mode & DMEXCL)) {
+		dir->mode |= DMEXCL;
+		dir->qid.type |= QTEXCL;
+		if (dirfwstat(lckfd, dir) < 0)
+			sysfatal("can't make %s exclusive access: %r", lock);
+	}
+	free(dir);
+	return lckfd;
+}
+
+void
+main(int argc, char *argv[])
+{
+	int fd, lckfd, lckpid, cmdpid;
+	char *cmd, *p, *lock;
+	char **args;
+	char *argarr[2];
+	Waitmsg *w;
+
+	ARGBEGIN {
+	case 'd':
+		++debug;
+		break;
+	case 'w':
+		++lockwait;
+		break;
+	default:
+		usage();
+		break;
+	} ARGEND
+
+	if (argc < 1)
+		usage();
+	if (argc == 1) {
+		args = argarr;
+		args[0] = cmd = "rc";
+		args[1] = nil;
+	} else {
+		cmd = argv[1];
+		args = &argv[1];
+	}
+
+	/* set up lock and process to keep it alive */
+	lock = argv[0];
+	lckfd = openlock(lock);
+	lckpid = fork();
+	switch(lckpid){
+	case -1:
+		error("fork");
+	case 0:
+		/* keep lock alive until killed */
+		for (;;) {
+			sleep(60*1000);
+			seek(lckfd, 0, 0);
+			fprint(lckfd, "\n");
+		}
+	}
+
+	/* spawn argument command */
+	cmdpid = rfork(RFFDG|RFREND|RFPROC|RFENVG);
+	switch(cmdpid){
+	case -1:
+		error("fork");
+	case 0:
+		fd = create("/env/prompt", OWRITE, 0666);
+		if (fd >= 0) {
+			fprint(fd, "%s%% ", lock);
+			close(fd);
+		}
+		exec(cmd, args);
+		if(cmd[0] != '/' && strncmp(cmd, "./", 2) != 0 &&
+		   strncmp(cmd, "../", 3) != 0)
+			exec(smprint("/bin/%s", cmd), args);
+		error(cmd);
+	}
+
+	notify(notifyf);
+
+	w = waitfor(cmdpid);
+	if (w == nil)
+		error("wait");
+
+	postnote(PNPROC, lckpid, "die");
+	waitfor(lckpid);
+	if(w->msg[0]){
+		p = utfrune(w->msg, ':');
+		if(p && p[1])
+			p++;
+		else
+			p = w->msg;
+		while (isspace(*p))
+			p++;
+		fprint(2, "%s: %s  # status=%s\n", argv0, cmd, p);
+	}
+	exits(w->msg);
+}
+
+void
+error(char *s)
+{
+	fprint(2, "%s: %s: %r\n", argv0, s);
+	exits(s);
+}
+
+void
+notifyf(void *a, char *s)
+{
+	USED(a);
+	if(strcmp(s, "interrupt") == 0)
+		noted(NCONT);
+	noted(NDFLT);
+}
-- 
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