mothra: run page in own note group, close unneeded filedescriptors after forking

running page in own note group avoids killing it when we
exit mothra.

copypaste dupfds() function from page and use it to close
unneeded file descriptors.

1 files changed, 32 insertions, 11 deletions

diff --git a/sys/src/cmd/mothra/mothra.c b/sys/src/cmd/mothra/mothra.c
index 29e9219fd..6ea1b850e 100644
--- a/sys/src/cmd/mothra/mothra.c
+++ b/sys/src/cmd/mothra/mothra.c
@@ -748,14 +748,12 @@ void dolink(Panel *p, int buttons, Rtext *word){
 }
 
 void filter(char *cmd, int fd){
-	switch(rfork(RFFDG|RFPROC|RFMEM|RFNOWAIT)){
+	switch(rfork(RFFDG|RFPROC|RFMEM|RFNOWAIT|RFNOTEG)){
 	case -1:
 		message("Can't fork!");
 		break;
 	case 0:
-		close(0);
-		dup(fd, 0);
-		close(fd);
+		dupfds(fd, 1, 2, -1);
 		execl("/bin/rc", "rc", "-c", cmd, 0);
 		_exits(0);
 	}
@@ -796,6 +794,32 @@ void freetext(Rtext *t){
 	plrtfree(tt);
 }
 
+void
+dupfds(int fd, ...)
+{
+	int mfd, n, i;
+	va_list arg;
+	Dir *dir;
+
+	va_start(arg, fd);
+	for(mfd = 0; fd >= 0; fd = va_arg(arg, int), mfd++)
+		if(fd != mfd)
+			if(dup(fd, mfd) < 0)
+				sysfatal("dup: %r");
+	va_end(arg);
+	if((fd = open("/fd", OREAD)) < 0)
+		sysfatal("open: %r");
+	n = dirreadall(fd, &dir);
+	for(i=0; i<n; i++){
+		if(strstr(dir[i].name, "ctl"))
+			continue;
+		fd = atoi(dir[i].name);
+		if(fd >= mfd)
+			close(fd);
+	}
+	free(dir);
+}
+
 int pipeline(char *cmd, int fd)
 {
 	int pfd[2];
@@ -806,22 +830,19 @@ Err:
 		werrstr("pipeline for %s failed: %r", cmd);
 		return -1;
 	}
-	switch(fork()){
+	switch(rfork(RFFDG|RFPROC|RFMEM|RFNOWAIT)){
 	case -1:
 		close(pfd[0]);
 		close(pfd[1]);
 		goto Err;
 	case 0:
-		dup(fd, 0);
-		dup(pfd[0], 1);
-		close(pfd[0]);
-		close(pfd[1]);
+		dupfds(fd, pfd[1], 2, -1);
 		execl("/bin/rc", "rc", "-c", cmd, 0);
 		_exits(0);
 	}
-	close(pfd[0]);
 	close(fd);
-	return pfd[1];
+	close(pfd[1]);
+	return pfd[0];
 }
 
 char*