From d51310678e4ce59b94576bd294118f62c4a8a158 Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Tue, 24 Sep 2024 14:42:30 +0000
Subject: [PATCH] util: Statically allocate size buffer

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/tui.c  | 18 ++++++++++++------
 src/util.c | 23 ++++++++++++-----------
 src/util.h |  6 +++++-
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/src/tui.c b/src/tui.c
index 96863f7..ef23556 100644
--- a/src/tui.c
+++ b/src/tui.c
@@ -114,6 +114,7 @@ static int fireperf_tui_setup_frame(struct fireperf_tui* tui) {
 
 static int fireperf_tui_update_status(struct fireperf_tui* tui) {
 	const struct fireperf_stats* stats = NULL;
+	char buffer[32];
 	int r;
 
 	int max_x = 0;
@@ -142,11 +143,16 @@ static int fireperf_tui_update_status(struct fireperf_tui* tui) {
 	if (r < 0)
 		goto ERROR;
 
+	// Fetch peak bandwidth
 	size_t peak_bps = fireperf_tui_get_peak_bps(tui, max_x);
 
+	// Format peak bandwidth
+	r = format_size(buffer, peak_bps, FIREPERF_FORMAT_BITS);
+	if (r < 0)
+		goto ERROR;
+
 	// Print Peak Bandwidth
-	r = asprintf(&status_l, "%s, Peak Bandwidth: %s", status_l,
-		format_size(peak_bps, FIREPERF_FORMAT_BITS));
+	r = asprintf(&status_l, "%s, Peak Bandwidth: %s", status_l, buffer);
 	if (r < 0)
 		goto ERROR;
 
@@ -340,7 +346,8 @@ int fireperf_tui_action(struct fireperf_tui* tui) {
 */
 static int fireperf_tui_draw_graph(struct fireperf_tui* tui) {
 	const struct fireperf_stats* stats = NULL;
-	char* scale = NULL;
+	char scale[32];
+	int r;
 
 	int max_x = 0;
 	int max_y = 0;
@@ -361,8 +368,8 @@ static int fireperf_tui_draw_graph(struct fireperf_tui* tui) {
 
 	// Draw the grid
 	for (double line = 0; line <= 1; line += 0.25) {
-		scale = format_size(line * peak_bps, FIREPERF_FORMAT_BITS);
-		if (!scale)
+		r = format_size(scale, line * peak_bps, FIREPERF_FORMAT_BITS);
+		if (r < 0)
 			continue;
 
 		size_t l = strlen(scale);
@@ -374,7 +381,6 @@ static int fireperf_tui_draw_graph(struct fireperf_tui* tui) {
 
 		// Write the scale
 		mvwaddnstr(tui->graph, max_y - (max_y * line), max_x - l, scale, l);
-		free(scale);
 	}
 
 	wattroff(tui->graph, COLOR_PAIR(5));
diff --git a/src/util.c b/src/util.c
index 558a478..de4715e 100644
--- a/src/util.c
+++ b/src/util.c
@@ -18,6 +18,7 @@
 #                                                                             #
 #############################################################################*/
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
@@ -28,9 +29,10 @@
 static const char* suffixes_bytes[] = { "B", "KiB", "MiB", "GiB", "TiB", NULL };
 static const char* suffixes_bits[]  = { "b", "Kb", "Mb", "Gb", "Tb", NULL };
 
-char* format_size(ssize_t size, int unit) {
-	const char** suffixes;
+int __format_size(char* buffer, const size_t length, ssize_t size, const int unit) {
+	const char** suffixes = NULL;
 	unsigned int divisor;
+	int r;
 
 	switch (unit) {
 		case FIREPERF_FORMAT_BYTES:
@@ -45,11 +47,10 @@ char* format_size(ssize_t size, int unit) {
 
 		// Invalid input
 		default:
-			return NULL;
+			return -EINVAL;
 	}
 
-	const char** suffix;
-	char* retval = NULL;
+	const char** suffix = NULL;
 
 	// Convert into double
 	double s = size;
@@ -62,19 +63,19 @@ char* format_size(ssize_t size, int unit) {
 	}
 
 	if (!*suffix)
-		return NULL;
+		return -EINVAL;
 
 	// Format the output string
-	int r = asprintf(&retval, "%.02f %s", s, *suffix);
+	r = snprintf(buffer, length, "%.02f %s", s, *suffix);
 	if (r < 0)
-		return NULL;
+		return r;
 
-	return retval;
+	return 0;
 }
 
-static char __timespec[20];
-
 const char* format_timespec(const struct timespec* t) {
+	static char __thread __timespec[20];
+
 	// Convert to local time
 	struct tm* tm = localtime(&t->tv_sec);
 
diff --git a/src/util.h b/src/util.h
index 8315b94..32c3f2a 100644
--- a/src/util.h
+++ b/src/util.h
@@ -26,6 +26,10 @@ enum {
 	FIREPERF_FORMAT_BITS,
 };
 
-char* format_size(ssize_t size, int unit);
+#define format_size(buffer, size, unit) \
+	__format_size(buffer, sizeof(buffer), size, unit)
+
+int __format_size(char* buffer, const size_t length, ssize_t size, const int unit);
+
 const char* format_timespec(const struct timespec* t);
 double timespec_delta(struct timespec* t1, struct timespec* t2);
-- 
2.47.2