[PATCH 2/9] lib: term: return error code from term_getsize()

[Ahmad Fatoum <a.fatoum@barebox.org>]

Instead of silently writing a magic value of 256 into the output
parameters on error, let callers distinguish the case that
"no interactive console responded" from a legitimate terminal size
by means of an error code.

No current user makes use of the 256 magic value, so we only need to
change term_getsize() itself.

Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 include/term.h |  2 +-
 lib/term.c     | 32 +++++++++++++++++++-------------
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/include/term.h b/include/term.h
index 097f84681d49..e53fcffcfc28 100644
--- a/include/term.h
+++ b/include/term.h
@@ -3,6 +3,6 @@
 #define __TERM_H
 
 void term_setpos(int x, int y);
-void term_getsize(int *screenwidth, int *screenheight);
+int term_getsize(int *screenwidth, int *screenheight);
 
 #endif /* __LIBBB_H */
diff --git a/lib/term.c b/lib/term.c
index 0aa4612d0b08..78158a3036c3 100644
--- a/lib/term.c
+++ b/lib/term.c
@@ -11,20 +11,17 @@ void term_setpos(int x, int y)
 	printf("\x1b[%d;%dH", y + 2, x + 1);
 }
 
-void term_getsize(int *screenwidth, int *screenheight)
+int term_getsize(int *screenwidth, int *screenheight)
 {
 	int n;
+	int width = INT_MAX, height = INT_MAX;
+	bool found = false;
 	char *endp;
 	const char esc[] = "\e7" "\e[r" "\e[999;999H" "\e[6n";
 	char buf[64];
 
-	if (screenwidth)
-		*screenwidth = 256;
-	if (screenheight)
-		*screenheight = 256;
-
 	for_each_console(cdev) {
-		int width, height;
+		int w, h;
 		uint64_t start;
 
 		if (!(cdev->f_active & CONSOLE_STDIN))
@@ -60,14 +57,23 @@ void term_getsize(int *screenwidth, int *screenheight)
 		if (buf[1] != '[')
 			continue;
 
-		height = simple_strtoul(buf + 2, &endp, 10);
-		width = simple_strtoul(endp + 1, NULL, 10);
+		h = simple_strtoul(buf + 2, &endp, 10);
+		w = simple_strtoul(endp + 1, NULL, 10);
 
-		if (screenwidth)
-			*screenwidth = min(*screenwidth, width);
-		if (screenheight)
-			*screenheight = min(*screenheight, height);
+		width = min(w, width);
+		height = min(h, height);
+		found = true;
 	}
 
 	term_setpos(0, 0);
+
+	if (!found)
+		return -ENOENT;
+
+	if (screenwidth)
+		*screenwidth = width;
+	if (screenheight)
+		*screenheight = height;
+
+	return 0;
 }
-- 
2.47.3