From 27a205e90fe95de78eddbc46e788881e5cafaf40 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Mon, 13 Apr 2020 11:42:10 +0200
Subject: [PATCH] term: reset: plug memory leak

In reset, we allocated new rows for all the currently visible
lines. We did **not** however, free the 'old' rows.

Fix by not explicitly allocating new rows, but instead allocating
uninitialized rows when needed, and then explicitly erasing the row.

If there already was a row allocated, it is simply erased. If there
wasn't, the a new line is malloc:ed, and then erased.
---
 CHANGELOG.md |  1 +
 terminal.c   | 58 ++++++++++++++++++++++++++++------------------------
 2 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0a336623..59fa0535 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -49,6 +49,7 @@
 * OSC 4 with multiple `c;spec` pairs.
 * Alt+Return to emit "ESC \r".
 * Trackpad sloooow scrolling to eventually scroll a line.
+* Memory leak in terminal reset.
 
 
 ### Security
diff --git a/terminal.c b/terminal.c
index c948c314..8c0ec60c 100644
--- a/terminal.c
+++ b/terminal.c
@@ -1106,6 +1106,31 @@ term_destroy(struct terminal *term)
     return ret;
 }
 
+static inline void
+erase_cell_range(struct terminal *term, struct row *row, int start, int end)
+{
+    assert(start < term->cols);
+    assert(end < term->cols);
+
+    if (unlikely(term->vt.attrs.have_bg)) {
+        for (int col = start; col <= end; col++) {
+            struct cell *c = &row->cells[col];
+            c->wc = 0;
+            c->attrs = (struct attributes){.have_bg = 1, .bg = term->vt.attrs.bg};
+        }
+    } else
+        memset(&row->cells[start], 0, (end - start + 1) * sizeof(row->cells[0]));
+
+    row->dirty = true;
+}
+
+static inline void
+erase_line(struct terminal *term, struct row *row)
+{
+    erase_cell_range(term, row, 0, term->cols - 1);
+    row->linebreak = false;
+}
+
 void
 term_reset(struct terminal *term, bool hard)
 {
@@ -1175,8 +1200,12 @@ term_reset(struct terminal *term, bool hard)
     term->normal.offset = term->normal.view = 0;
     term->alt.offset = term->alt.view = 0;
     for (size_t i = 0; i < term->rows; i++) {
-        term->normal.rows[i] = grid_row_alloc(term->cols, true);
-        term->alt.rows[i] = grid_row_alloc(term->cols, true);
+        struct row *r = grid_row_and_alloc(&term->normal, i);
+        erase_line(term, r);
+    }
+    for (size_t i = 0; i < term->rows; i++) {
+        struct row *r = grid_row_and_alloc(&term->alt, i);
+        erase_line(term, r);
     }
     for (size_t i = term->rows; i < term->normal.num_rows; i++) {
         grid_row_free(term->normal.rows[i]);
@@ -1356,31 +1385,6 @@ term_damage_scroll(struct terminal *term, enum damage_type damage_type,
     tll_push_back(term->grid->scroll_damage, dmg);
 }
 
-static inline void
-erase_cell_range(struct terminal *term, struct row *row, int start, int end)
-{
-    assert(start < term->cols);
-    assert(end < term->cols);
-
-    if (unlikely(term->vt.attrs.have_bg)) {
-        for (int col = start; col <= end; col++) {
-            struct cell *c = &row->cells[col];
-            c->wc = 0;
-            c->attrs = (struct attributes){.have_bg = 1, .bg = term->vt.attrs.bg};
-        }
-    } else
-        memset(&row->cells[start], 0, (end - start + 1) * sizeof(row->cells[0]));
-
-    row->dirty = true;
-}
-
-static inline void
-erase_line(struct terminal *term, struct row *row)
-{
-    erase_cell_range(term, row, 0, term->cols - 1);
-    row->linebreak = false;
-}
-
 void
 term_erase(struct terminal *term, const struct coord *start, const struct coord *end)
 {