[PATCH 1/2] telemetry: use malloc instead of variable length array

[Tyler Retzlaff]

Replace use of variable length array optional standard feature to
improve portability.

Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
---
 lib/telemetry/telemetry_json.h | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/lib/telemetry/telemetry_json.h b/lib/telemetry/telemetry_json.h
index 744bbfe..c375e97 100644
--- a/lib/telemetry/telemetry_json.h
+++ b/lib/telemetry/telemetry_json.h
@@ -30,18 +30,23 @@
 static inline int
 __json_snprintf(char *buf, const int len, const char *format, ...)
 {
-       char tmp[len];
+       char *tmp = malloc(len);
        va_list ap;
-       int ret;
+       int ret = 0;
+
+       if (tmp == NULL)
+               return ret;
 
        va_start(ap, format);
        ret = vsnprintf(tmp, sizeof(tmp), format, ap);
        va_end(ap);
        if (ret > 0 && ret < (int)sizeof(tmp) && ret < len) {
                strcpy(buf, tmp);
-               return ret;
        }
-       return 0; /* nothing written or modified */
+
+       free(tmp);
+
+       return ret;
 }
 
 static const char control_chars[0x20] = {
@@ -60,13 +65,17 @@
 static inline int
 __json_format_str(char *buf, const int len, const char *prefix, const char 
*str, const char *suffix)
 {
-       char tmp[len];
        int tmpidx = 0;
+       int ret = 0;
+       char *tmp = malloc(len);
+
+       if (tmp == NULL)
+               return ret;
 
        while (*prefix != '\0' && tmpidx < len)
                tmp[tmpidx++] = *prefix++;
        if (tmpidx >= len)
-               return 0;
+               goto cleanup;
 
        while (*str != '\0') {
                if (*str < (int)RTE_DIM(control_chars)) {
@@ -85,19 +94,24 @@
                 * escaped character like "\n" without overflowing
                 */
                if (tmpidx > len - 2)
-                       return 0;
+                       goto cleanup;
                str++;
        }
 
        while (*suffix != '\0' && tmpidx < len)
                tmp[tmpidx++] = *suffix++;
        if (tmpidx >= len)
-               return 0;
+               goto cleanup;
 
        tmp[tmpidx] = '\0';
 
        strcpy(buf, tmp);
-       return tmpidx;
+       ret = tmpidx;
+
+cleanup:
+       free(tmp);
+
+       return ret;
 }
 
 /* Copies an empty array into the provided buffer. */
-- 
1.8.3.1