From 32f2d9d089ced7d693aa412821f1d66134877cf0 Mon Sep 17 00:00:00 2001
From: nicm <nicm>
Date: Tue, 6 Jul 2021 08:26:00 +0000
Subject: [PATCH] Improve error reporting when the tmux /tmp directory cannot
 be created or used, GitHub issue 2765 from Uwe Kleine-Koenig.

---
 tmux.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/tmux.c b/tmux.c
index 16877407..55ab9751 100644
--- a/tmux.c
+++ b/tmux.c
@@ -211,16 +211,22 @@ make_label(const char *label, char **cause)
 	free(paths);
 
 	xasprintf(&base, "%s/tmux-%ld", path, (long)uid);
-	if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST)
+	if (mkdir(base, S_IRWXU) != 0 && errno != EEXIST) {
+		xasprintf(cause, "couldn't create directory %s (%s)", base,
+		    strerror(errno));
 		goto fail;
-	if (lstat(base, &sb) != 0)
+	}
+	if (lstat(base, &sb) != 0) {
+		xasprintf(cause, "couldn't read directory %s (%s)", base,
+		    strerror(errno));
 		goto fail;
+	}
 	if (!S_ISDIR(sb.st_mode)) {
-		errno = ENOTDIR;
+		xasprintf(cause, "%s is not a directory", base);
 		goto fail;
 	}
 	if (sb.st_uid != uid || (sb.st_mode & S_IRWXO) != 0) {
-		errno = EACCES;
+		xasprintf(cause, "directory %s has unsafe permissions", base);
 		goto fail;
 	}
 	xasprintf(&path, "%s/%s", base, label);
@@ -228,7 +234,6 @@ make_label(const char *label, char **cause)
 	return (path);
 
 fail:
-	xasprintf(cause, "error creating %s (%s)", base, strerror(errno));
 	free(base);
 	return (NULL);
 }