utils strbuf: Handle nul-byte correctly.

[sysdb.git] / src / utils / strbuf.c

diff --git a/src/utils/strbuf.c b/src/utils/strbuf.c
index 4d8fc8b91ba234df10edd8d15d552169bcbf9930..77d19f044d71a1fec89ec629877d0deda5b3585d 100644 (file)
--- a/src/utils/strbuf.c
+++ b/src/utils/strbuf.c
@@ -119,9 +119,14 @@ sdb_strbuf_vappend(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
 
        assert((strbuf->size == 0) || (strbuf->string[strbuf->pos] == '\0'));
 
-       if (strbuf->pos >= strbuf->size)
+       if (! strbuf->size) {
                /* use some arbitrary but somewhat reasonable default */
-               if (strbuf_resize(strbuf, strbuf->size ? 2 * strbuf->size : 64))
+               if (strbuf_resize(strbuf, 64))
+                       return -1;
+       }
+       /* make sure to reserve space for the nul-byte */
+       else if (strbuf->pos >= strbuf->size - 1)
+               if (strbuf_resize(strbuf, 2 * strbuf->size))
                        return -1;
 
        assert(strbuf->size && strbuf->string);
@@ -137,8 +142,12 @@ sdb_strbuf_vappend(sdb_strbuf_t *strbuf, const char *fmt, va_list ap)
                return status;
        }
 
-       if ((size_t)status >= strbuf->size - strbuf->pos) {
-               strbuf_resize(strbuf, (size_t)status + 1);
+       /* 'status' does not include nul-byte */
+       if ((size_t)status >= strbuf->size - strbuf->pos - 1) {
+               if (strbuf_resize(strbuf, strbuf->size + (size_t)status)) {
+                       va_end(aq);
+                       return -1;
+               }
 
                /* reset string and try again */
                strbuf->string[strbuf->pos] = '\0';