MINOR: cache: Use dedicated trash for "show cache" cli command

After the latest changes in the cache/shared_context mechanism, the
cache and shared_context logic were decorrelated and in some unlikely
cases we might end up using the "show cache" command while some regular
cache processing is occurring (a response being stored in the cache for
instance). In such a case, because we used the same 'trash' buffer in
those two contexts, we could end up with the contents of a response in
the ouput of the "show cache" command.
This patch fixes this problem by allocating a dedicated trash for the
CLI command.

diff --git a/src/cache.c b/src/cache.c
index 60125c8e7e2b3e59f1c8b2f000fbed660e0a4660..36d0412812ec34a8157015aa86360ae5074e7a9a 100644 (file)
--- a/src/cache.c
+++ b/src/cache.c
@@ -2665,6 +2665,10 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
 {
        struct show_cache_ctx *ctx = appctx->svcctx;
        struct cache* cache = ctx->cache;
+       struct buffer *buf = alloc_trash_chunk();
+
+       if (buf == NULL)
+               return 1;
 
        list_for_each_entry_from(cache, &caches, list) {
                struct eb32_node *node = NULL;
@@ -2677,10 +2681,10 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
 
                next_key = ctx->next_key;
                if (!next_key) {
-                       chunk_printf(&trash, "%p: %s (shctx:%p, available blocks:%d)\n", cache, cache->id, shctx_ptr(cache), shctx_ptr(cache)->nbav);
-                       if (applet_putchk(appctx, &trash) == -1) {
+                       chunk_printf(buf, "%p: %s (shctx:%p, available blocks:%d)\n", cache, cache->id, shctx_ptr(cache), shctx_ptr(cache)->nbav);
+                       if (applet_putchk(appctx, buf) == -1) {
                                shctx_unlock(shctx);
-                               return 0;
+                               goto yield;
                        }
                }
                shctx_unlock(shctx);
@@ -2700,10 +2704,10 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
                        next_key = node->key + 1;
 
                        if (entry->expire > date.tv_sec) {
-                               chunk_printf(&trash, "%p hash:%u vary:0x", entry, read_u32(entry->hash));
+                               chunk_printf(buf, "%p hash:%u vary:0x", entry, read_u32(entry->hash));
                                for (i = 0; i < HTTP_CACHE_SEC_KEY_LEN; ++i)
-                                       chunk_appendf(&trash, "%02x", (unsigned char)entry->secondary_key[i]);
-                               chunk_appendf(&trash, " size:%u (%u blocks), refcount:%u, expire:%d\n",
+                                       chunk_appendf(buf, "%02x", (unsigned char)entry->secondary_key[i]);
+                               chunk_appendf(buf, " size:%u (%u blocks), refcount:%u, expire:%d\n",
                                              block_ptr(entry)->len, block_ptr(entry)->block_count,
                                              block_ptr(entry)->refcount, entry->expire - (int)date.tv_sec);
                        }
@@ -2711,17 +2715,21 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
 
                        ctx->next_key = next_key;
 
-                       if (applet_putchk(appctx, &trash) == -1) {
+                       if (applet_putchk(appctx, buf) == -1) {
                                cache_rdunlock(cache);
-                               return 0;
+                               goto yield;
                        }
                }
                cache_rdunlock(cache);
 
        }
 
+       free_trash_chunk(buf);
        return 1;
 
+yield:
+       free_trash_chunk(buf);
+       return 0;
 }