lib-test: Improved test-istream to catch more bugs

diff --git a/src/lib-test/test-common.c b/src/lib-test/test-common.c
index 11f3a46138eb95edc36ea8b5c2f87f666b9d69a2..108d3519a82f6981bb83fc5c53a0636f0bc5ad11 100644 (file)
--- a/src/lib-test/test-common.c
+++ b/src/lib-test/test-common.c
@@ -16,6 +16,7 @@ static unsigned int total_count;
 
 struct test_istream {
        struct istream_private istream;
+       const void *orig_buffer;
        unsigned int skip_diff;
        size_t max_pos;
        bool allow_eof;
@@ -25,6 +26,7 @@ static ssize_t test_read(struct istream_private *stream)
 {
        struct test_istream *tstream = (struct test_istream *)stream;
        unsigned int new_skip_diff;
+       size_t cur_max;
        ssize_t ret;
 
        i_assert(stream->skip <= stream->pos);
@@ -36,10 +38,9 @@ static ssize_t test_read(struct istream_private *stream)
                /* we seeked past the end of file. */
                ret = 0;
        } else {
-               /* move around the buffer */
+               /* copy data to a buffer in somewhat random place. this could
+                  help catch bugs. */
                new_skip_diff = rand() % 128;
-               stream->buffer = (stream->buffer + tstream->skip_diff) -
-                       new_skip_diff;
                stream->skip = (stream->skip - tstream->skip_diff) +
                        new_skip_diff;
                stream->pos = (stream->pos - tstream->skip_diff) +
@@ -48,8 +49,24 @@ static ssize_t test_read(struct istream_private *stream)
                        new_skip_diff;
                tstream->skip_diff = new_skip_diff;
 
-               ret = tstream->max_pos - stream->pos;
-               stream->pos = tstream->max_pos;
+               cur_max = tstream->max_pos;
+               if (stream->max_buffer_size < (size_t)-1 - stream->skip &&
+                   cur_max > stream->skip + stream->max_buffer_size)
+                       cur_max = stream->skip + stream->max_buffer_size;
+
+               /* use exactly correct buffer size so valgrind can catch
+                  read overflows */
+               if (stream->buffer_size != cur_max) {
+                       stream->w_buffer = i_realloc(stream->w_buffer, 0,
+                                                    cur_max);
+                       stream->buffer = stream->w_buffer;
+                       stream->buffer_size = cur_max;
+               }
+               memcpy(stream->w_buffer + new_skip_diff, tstream->orig_buffer,
+                      cur_max - new_skip_diff);
+
+               ret = cur_max - stream->pos;
+               stream->pos = cur_max;
        }
 
        if (ret > 0)
@@ -78,7 +95,7 @@ struct istream *test_istream_create_data(const void *data, size_t size)
        struct test_istream *tstream;
 
        tstream = i_new(struct test_istream, 1);
-       tstream->istream.buffer = data;
+       tstream->orig_buffer = data;
 
        tstream->istream.read = test_read;
        tstream->istream.seek = test_seek;