From 245264e3716c46a5278f705c90d9cb24afca0924 Mon Sep 17 00:00:00 2001
From: Ori Bernstein <ori@eigenstate.org>
Date: Sat, 20 Feb 2021 12:49:03 -0800
Subject: upas/marshal: handle nonexistent save folder correctly (thanks
 sirjofri)

When the save folder did not exist, and we could not create
it, we would handle up to one Biobuf worth of message, and
then fail, due to a failed tee. The sequence of events leading
up to this was:

	openfolder() -> error
	tee(0, fd, -1) -> wait for read
	write(0, data) ->
		write(fd, data) -> ok
		write(-1, data) -> error, tee terminates
	write(0, attachment) -> error

This change prevents us from writing to a closed fd, and
therefore from erroring out when sending.

We also warn the user.
---
 sys/src/cmd/upas/marshal/marshal.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/sys/src/cmd/upas/marshal/marshal.c b/sys/src/cmd/upas/marshal/marshal.c
index 3e26d9dbf..893775b03 100644
--- a/sys/src/cmd/upas/marshal/marshal.c
+++ b/sys/src/cmd/upas/marshal/marshal.c
@@ -985,10 +985,12 @@ tee(int in, int out1, int out2)
 	int n;
 	char buf[8*1024];
 
-	while ((n = read(in, buf, sizeof buf)) > 0)
-		if (write(out1, buf, n) != n ||
-		    write(out2, buf, n) != n)
+	while ((n = read(in, buf, sizeof buf)) > 0){
+		if(out1 != -1 && write(out1, buf, n) != n)
 			break;
+		if(out2 != -1 && write(out2, buf, n) != n)
+			break;
+	}
 }
 
 /* print the unix from line */
@@ -1033,7 +1035,7 @@ int
 sendmail(Addr *to, Addr *cc, Addr *bcc, int *pid, char *rcvr)
 {
 	int ac, fd, pfd[2];
-	char **v, cmd[Pathlen];
+	char **v, *f, cmd[Pathlen];
 	Addr *a;
 	Biobuf *b;
 
@@ -1086,12 +1088,18 @@ sendmail(Addr *to, Addr *cc, Addr *bcc, int *pid, char *rcvr)
 			case 0:
 				close(pfd[0]);
 				/* BOTCH; "From " time gets changed */
-				b = openfolder(foldername(nil, user, rcvr), time(0));
-				fd = b? Bfildes(b): -1;
-				printunixfrom(fd);
-				tee(0, pfd[1], fd);
-				write(fd, "\n", 1);
-				closefolder(b);
+				f = foldername(nil, user, rcvr);
+				b = openfolder(f, time(0));
+				if(b != nil){
+					fd = Bfildes(b);
+					printunixfrom(fd);
+					tee(0, pfd[1], fd);
+					write(fd, "\n", 1);
+					closefolder(b);
+				}else{
+					fprint(2, "warning: open %s: %r", f);
+					tee(0, pfd[1], -1);
+				}
 				exits(0);
 			default:
 				close(pfd[1]);
@@ -1172,6 +1180,7 @@ waitforsubprocs(void)
 
 	err = nil;
 	while((w = wait()) != nil){
+		fprint(2, "%d: %s\n", w->pid, w->msg);
 		if(w->pid == pid || w->pid == pgppid)
 			if(w->msg[0] != 0)
 				err = estrdup(w->msg);
-- 
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