core: allow arbitrary lengths in read_config

Signed-off-by: Thiago Padilha <[email protected]>

src/config_format/flb_cf_fluentbit.c

@@ -40,7 +40,6 @@
 #define PATH_MAX MAX_PATH
 #endif
 
-#define FLB_CF_BUF_SIZE     4096
 #define FLB_CF_FILE_NUM_LIMIT 1000
 
 /* indent checker return codes */
@@ -418,6 +417,8 @@ static int read_config(struct flb_cf *cf, struct local_ctx *ctx,
     char *val = NULL;
     int val_len;
     char *buf;
+    size_t bufsize = 4096;
+    long fpos = 0;
     char tmp[PATH_MAX];
     flb_sds_t section = NULL;
     flb_sds_t indent = NULL;
@@ -486,7 +487,7 @@ static int read_config(struct flb_cf *cf, struct local_ctx *ctx,
 #endif
 
     /* Allocate temporal buffer to read file content */
-    buf = flb_malloc(FLB_CF_BUF_SIZE);
+    buf = flb_malloc(bufsize);
     if (!buf) {
         flb_errno();
         goto error;
@@ -501,26 +502,33 @@ static int read_config(struct flb_cf *cf, struct local_ctx *ctx,
     while (static_fgets(buf, FLB_CF_BUF_SIZE, in_data, &off)) {
 #else
     /* normal mode, read lines into a buffer */
-    while (fgets(buf, FLB_CF_BUF_SIZE, f)) {
+    while (fgets(buf, bufsize, f)) {
 #endif
         len = strlen(buf);
         if (len > 0 && buf[len - 1] == '\n') {
+            fpos += len;
             buf[--len] = 0;
             if (len && buf[len - 1] == '\r') {
                 buf[--len] = 0;
             }
         }
 #ifndef FLB_HAVE_STATIC_CONF
         else {
-            /*
-             * If we don't find a break line, validate if we got an EOF or not. No EOF
-             * means that the incoming string is not finished so we must raise an
-             * exception.
-             */
-            if (!feof(f)) {
-                config_error(cfg_file, line, "length of content has exceeded limit");
+            /* resize the line buffer */
+            bufsize *= 2;
+            buf = flb_realloc(buf, bufsize);
+            if (!buf) {
+                flb_error("failed to resize line buffer to %zu", bufsize);
+                flb_errno();
                 goto error;
             }
+            /* return to the previous file position */
+            if (fseek(f, fpos, SEEK_SET) != 0) {
+                flb_errno();
+                goto error;
+            }
+            /* try again */
+            continue;
         }
 #endif