Fix: memory is not zeroed on first set_capacity

[lttng-tools.git] / src / common / dynamic-buffer.c

diff --git a/src/common/dynamic-buffer.c b/src/common/dynamic-buffer.c
index 05d3022af19d0e4e8ef9d0527a6069394131eb6b..aef80dded0bab2785820f7cf8acb1f7b9071cf7b 100644 (file)
--- a/src/common/dynamic-buffer.c
+++ b/src/common/dynamic-buffer.c
@@ -16,7 +16,6 @@
  */
 
 #include <common/dynamic-buffer.h>
-#include <common/macros.h>
 #include <common/utils.h>
 #include <assert.h>
 
@@ -38,12 +37,14 @@ size_t round_to_power_of_2(size_t val)
        return rounded;
 }
 
+LTTNG_HIDDEN
 void lttng_dynamic_buffer_init(struct lttng_dynamic_buffer *buffer)
 {
        assert(buffer);
        memset(buffer, 0, sizeof(*buffer));
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_append(struct lttng_dynamic_buffer *buffer,
                const void *buf, size_t len)
 {
@@ -59,11 +60,11 @@ int lttng_dynamic_buffer_append(struct lttng_dynamic_buffer *buffer,
                goto end;
        }
 
-       assert(buffer->capacity >= buffer->size);
-       if (buffer->capacity < (len + buffer->size)) {
+       assert(buffer->_capacity >= buffer->size);
+       if (buffer->_capacity < (len + buffer->size)) {
                ret = lttng_dynamic_buffer_set_capacity(buffer,
-                               buffer->capacity +
-                               (len - (buffer->capacity - buffer->size)));
+                               buffer->_capacity +
+                               (len - (buffer->_capacity - buffer->size)));
                if (ret) {
                        goto end;
                }
@@ -75,6 +76,7 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_append_buffer(struct lttng_dynamic_buffer *dst_buffer,
                struct lttng_dynamic_buffer *src_buffer)
 {
@@ -91,6 +93,7 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_set_size(struct lttng_dynamic_buffer *buffer,
                size_t new_size)
 {
@@ -104,23 +107,13 @@ int lttng_dynamic_buffer_set_size(struct lttng_dynamic_buffer *buffer,
                goto end;
        }
 
-       if (new_size > buffer->capacity) {
-               size_t original_size = buffer->size;
-               size_t original_capacity = buffer->capacity;
-
+       if (new_size > buffer->_capacity) {
                ret = lttng_dynamic_buffer_set_capacity(buffer, new_size);
                if (ret) {
                        goto end;
                }
 
-               /*
-                * Zero-initialize the space that was left in the buffer at the
-                * before we increased its capacity (original capacity - original size).
-                * The newly acquired capacity (new capacity - original capacity)
-                * is zeroed by lttng_dynamic_buffer_set_capacity().
-                */
-               memset(buffer->data + original_size, 0,
-                               original_capacity - original_size);
+               memset(buffer->data + buffer->size, 0, new_size - buffer->size);
        } else if (new_size > buffer->size) {
                memset(buffer->data + buffer->size, 0, new_size - buffer->size);
        } else {
@@ -139,12 +132,14 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 int lttng_dynamic_buffer_set_capacity(struct lttng_dynamic_buffer *buffer,
                size_t demanded_capacity)
 {
        int ret = 0;
        void *new_buf;
-       size_t new_capacity = round_to_power_of_2(demanded_capacity);
+       size_t new_capacity = demanded_capacity ?
+                       round_to_power_of_2(demanded_capacity) : 0;
 
        if (!buffer || demanded_capacity < buffer->size) {
                /*
@@ -155,7 +150,7 @@ int lttng_dynamic_buffer_set_capacity(struct lttng_dynamic_buffer *buffer,
                goto end;
        }
 
-       if (new_capacity == buffer->capacity) {
+       if (new_capacity == buffer->_capacity) {
                goto end;
        }
 
@@ -166,18 +161,29 @@ int lttng_dynamic_buffer_set_capacity(struct lttng_dynamic_buffer *buffer,
                goto end;
        }
        buffer->data = new_buf;
-       buffer->capacity = new_capacity;
+       buffer->_capacity = new_capacity;
 end:
        return ret;
 }
 
 /* Release any memory used by the dynamic buffer. */
+LTTNG_HIDDEN
 void lttng_dynamic_buffer_reset(struct lttng_dynamic_buffer *buffer)
 {
        if (!buffer) {
                return;
        }
        buffer->size = 0;
-       buffer->capacity = 0;
+       buffer->_capacity = 0;
        free(buffer->data);
 }
+
+LTTNG_HIDDEN
+size_t lttng_dynamic_buffer_get_capacity_left(
+               struct lttng_dynamic_buffer *buffer)
+{
+       if (!buffer) {
+               return 0;
+       }
+       return buffer->_capacity - buffer->size;
+}