[PATCH alsa-lib 8/8] topology: Make buffer for saving dynamic size

[Piotr Maziarz]

Some fields can exceed size limit, e.g. private data has no size
restriction. Therefore it needs to be dynamically increased.

Signed-off-by: Piotr Maziarz <piotrx.maziarz at linux.intel.com>
---
 src/topology/save.c | 36 ++++++++++++++++++++++++++++++------
 1 file changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/topology/save.c b/src/topology/save.c
index 4ecf86c..d6ee8b6 100644
--- a/src/topology/save.c
+++ b/src/topology/save.c
@@ -19,22 +19,43 @@
 #include "tplg_local.h"
 
 #define SAVE_ALLOC_SHIFT	(13)	/* 8192 bytes */
+#define PRINT_BUF_SIZE		(1024)
+#define PRINT_BUF_SIZE_MAX	(1024 * 1024)
 
 int tplg_save_printf(char **dst, const char *pfx, const char *fmt, ...)
 {
 	va_list va;
-	char buf[1024], *s;
-	size_t n, l, t, pl;
+	char *buf, *s;
+	size_t n, alloc_size = PRINT_BUF_SIZE, l, t, pl;
+	int ret = 0;
+
+	buf = malloc(alloc_size);
+	if (!buf)
+		return -ENOMEM;
 
 	if (pfx == NULL)
 		pfx = "";
 
+again:
 	va_start(va, fmt);
-	n = vsnprintf(buf, sizeof(buf), fmt, va);
+	n = vsnprintf(buf, alloc_size, fmt, va);
 	va_end(va);
 
-	if (n >= sizeof(buf))
-		return -EOVERFLOW;
+	if (n >= PRINT_BUF_SIZE_MAX) {
+		ret = -EOVERFLOW;
+		goto end;
+	}
+
+	if (n >= alloc_size) {
+		char *tmp = realloc(buf, n + 1);
+		if (!tmp) {
+			ret = -ENOMEM;
+			goto end;
+		}
+		buf = tmp;
+		alloc_size = n + 1;
+		goto again;
+	}
 
 	pl = strlen(pfx);
 	l = *dst ? strlen(*dst) : 0;
@@ -47,7 +68,8 @@ int tplg_save_printf(char **dst, const char *pfx, const char *fmt, ...)
 		if (s == NULL) {
 			free(*dst);
 			*dst = NULL;
-			return -ENOMEM;
+			ret = -ENOMEM;
+			goto end;
 		}
 	} else {
 		s = *dst;
@@ -57,6 +79,8 @@ int tplg_save_printf(char **dst, const char *pfx, const char *fmt, ...)
 		strcpy(s + l, pfx);
 	strcpy(s + l + pl, buf);
 	*dst = s;
+end:
+	free(buf);
 	return 0;
 }
 
-- 
2.7.4