Merge branch 'pr/1792'

[collectd.git] / src / daemon / common.c

diff --git a/src/daemon/common.c b/src/daemon/common.c
index 7806c71..e2c872c 100644 (file)
--- a/src/daemon/common.c
+++ b/src/daemon/common.c
@@ -334,50 +334,60 @@ int strsplit (char *string, char **fields, size_t size)
        return ((int) i);
 }
 
-int strjoin (char *buffer, size_t buffer_size,
-               char **fields, size_t fields_num,
-               const char *sep)
-{
-       size_t avail;
-       char *ptr;
-       size_t sep_len;
+int strjoin(char *buffer, size_t buffer_size, char **fields, size_t fields_num,
+            const char *sep) {
+  size_t avail = 0;
+  char *ptr = buffer;
+  size_t sep_len = 0;
 
-       if ((buffer_size < 1) || (fields_num == 0))
-               return (-1);
+  size_t buffer_req = 0;
 
-       memset (buffer, 0, buffer_size);
-       ptr = buffer;
-       avail = buffer_size - 1;
+  if (((fields_num != 0) && (fields == NULL)) ||
+      ((buffer_size != 0) && (buffer == NULL)))
+    return (-EINVAL);
 
-       sep_len = 0;
-       if (sep != NULL)
-               sep_len = strlen (sep);
+  if (buffer != NULL)
+    buffer[0] = 0;
 
-       for (size_t i = 0; i < fields_num; i++)
-       {
-               size_t field_len;
+  if (buffer_size != 0)
+    avail = buffer_size - 1;
 
-               if ((i > 0) && (sep_len > 0))
-               {
-                       if (avail < sep_len)
-                               return (-1);
+  if (sep != NULL)
+    sep_len = strlen(sep);
 
-                       memcpy (ptr, sep, sep_len);
-                       ptr += sep_len;
-                       avail -= sep_len;
-               }
+  for (size_t i = 0; i < fields_num; i++) {
+    size_t field_len = strlen(fields[i]);
 
-               field_len = strlen (fields[i]);
-               if (avail < field_len)
-                       return (-1);
+    if (i != 0)
+      buffer_req += sep_len;
+    buffer_req += field_len;
 
-               memcpy (ptr, fields[i], field_len);
-               ptr += field_len;
-               avail -= field_len;
-       }
+    if ((i != 0) && (sep_len > 0)) {
+      if (sep_len >= avail) {
+        /* prevent subsequent iterations from writing to the
+         * buffer. */
+        avail = 0;
+        continue;
+      }
+
+      memcpy(ptr, sep, sep_len);
+
+      ptr += sep_len;
+      avail -= sep_len;
+    }
+
+    if (field_len > avail)
+      field_len = avail;
+
+    memcpy(ptr, fields[i], field_len);
+    ptr += field_len;
+
+    avail -= field_len;
+    if (ptr != NULL)
+      *ptr = 0;
+  }
 
-       assert (buffer[buffer_size - 1] == 0);
-       return ((int) strlen (buffer));
+  return (int)buffer_req;
 }
 
 int escape_string (char *buffer, size_t buffer_size)