[PATCH] plugins/syscall: Added a table-like summary output

[Mahmoud Mandour]

Added a table-like output which contains the total number of calls
for each used syscall along with the number of errors that occurred.

Per-call tracing is still available through supplying the argument
``print`` to the plugin.

Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com>
---
 tests/plugin/syscall.c | 94 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 88 insertions(+), 6 deletions(-)

diff --git a/tests/plugin/syscall.c b/tests/plugin/syscall.c
index 53ee2ab6c4..b92340c636 100644
--- a/tests/plugin/syscall.c
+++ b/tests/plugin/syscall.c
@@ -16,32 +16,114 @@
 
 QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
 
+typedef struct {
+    int64_t calls;
+    int64_t errors;
+} SyscallStats;
+
+static GHashTable *syscalls_statistics;
+
+static bool percall_print;
+
 static void vcpu_syscall(qemu_plugin_id_t id, unsigned int vcpu_index,
                          int64_t num, uint64_t a1, uint64_t a2,
                          uint64_t a3, uint64_t a4, uint64_t a5,
                          uint64_t a6, uint64_t a7, uint64_t a8)
 {
-    g_autofree gchar *out = g_strdup_printf("syscall #%" PRIi64 "\n", num);
-    qemu_plugin_outs(out);
+    if (!percall_print) {
+        SyscallStats *syscall_entry;
+
+        syscall_entry =
+            (SyscallStats *) g_hash_table_lookup(syscalls_statistics,
+                                                  GINT_TO_POINTER(num));
+
+        if (!syscall_entry) {
+            syscall_entry = g_new(SyscallStats, 1);
+            syscall_entry->calls = 1;
+            syscall_entry->errors = 0;
+
+            g_hash_table_insert(syscalls_statistics, GINT_TO_POINTER(num),
+                                (gpointer) syscall_entry);
+        } else {
+            syscall_entry->calls++;
+        }
+    } else {
+        g_autofree gchar *out = g_strdup_printf("syscall #%" PRIi64 "\n", num);
+        qemu_plugin_outs(out);
+    }
 }
 
 static void vcpu_syscall_ret(qemu_plugin_id_t id, unsigned int vcpu_idx,
                              int64_t num, int64_t ret)
+{
+    if (!percall_print) {
+        SyscallStats *syscall_entry;
+
+        syscall_entry =
+            (SyscallStats *) g_hash_table_lookup(syscalls_statistics,
+                                                  GINT_TO_POINTER(num));
+        if (!syscall_entry) {
+            qemu_plugin_outs(g_strdup_printf("%" PRIi64 "\n", num));
+        }
+        if (ret < 0) {
+            syscall_entry->errors++;
+        }
+    } else {
+        g_autofree gchar *out;
+        out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
+                num, ret);
+        qemu_plugin_outs(out);
+    }
+}
+
+/* ************************************************************************* */
+
+void print_entry(gpointer key, gpointer val, gpointer user_data)
 {
     g_autofree gchar *out;
-    out = g_strdup_printf("syscall #%" PRIi64 " returned -> %" PRIi64 "\n",
-            num, ret);
+    int64_t syscall_num = (int64_t) key;
+    SyscallStats *syscall_entry = (SyscallStats *) val;
+    out = g_strdup_printf(
+        "%-13" PRIi64 "%-6" PRIi64 " %" PRIi64 "\n",
+        syscall_num, syscall_entry->calls, syscall_entry->errors);
     qemu_plugin_outs(out);
 }
 
-/* ************************************************************************* */
+static void plugin_exit(qemu_plugin_id_t id, void *p)
+{
+    if (!percall_print) {
+        qemu_plugin_outs("syscall no.  calls  errors\n");
+        g_hash_table_foreach(syscalls_statistics, &print_entry, NULL);
+    }
+}
 
-static void plugin_exit(qemu_plugin_id_t id, void *p) {}
+void free_entry(gpointer entry)
+{
+    g_free(entry);
+}
 
 QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
                                            const qemu_info_t *info,
                                            int argc, char **argv)
 {
+    int i;
+
+    for (i = 0; i < argc; i++) {
+        char *opt = argv[i];
+        if (g_strcmp0(opt, "print") == 0) {
+            percall_print = true;
+        } else {
+            fprintf(stderr, "unsupported argument: %s\n", opt);
+            return -1;
+        }
+    }
+
+    if (!percall_print) {
+        syscalls_statistics =
+            g_hash_table_new_full(g_direct_hash, g_direct_equal,
+                    NULL, &free_entry);
+    }
+
     qemu_plugin_register_vcpu_syscall_cb(id, vcpu_syscall);
     qemu_plugin_register_vcpu_syscall_ret_cb(id, vcpu_syscall_ret);
     qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
-- 
2.25.1