From a5dfc46176b766e89b71198b35103785dc171eab Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Fri, 9 Apr 2021 16:54:05 +0200
Subject: [PATCH] audit: pass and reuse NMStrBuf for build_message()

build_message() is an internal helper function with a very specific
purpose.

Let's change it to take an NMStrBuf argument for generating
the string. The advantage is that we don't need to allocate and
free the buffers in between, but can just reuse it.
---
 src/core/nm-audit-manager.c | 41 ++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/src/core/nm-audit-manager.c b/src/core/nm-audit-manager.c
index 44ba0e12bb..2ef5d86097 100644
--- a/src/core/nm-audit-manager.c
+++ b/src/core/nm-audit-manager.c
@@ -110,11 +110,16 @@ _audit_field_init_uint64(AuditField *field, const char *name, guint64 val, Audit
     };
 }
 
-static char *
-build_message(GPtrArray *fields, AuditBackend backend)
+static const char *
+build_message(NMStrBuf *strbuf, AuditBackend backend, GPtrArray *fields)
 {
-    NMStrBuf strbuf = NM_STR_BUF_INIT(NM_UTILS_GET_NEXT_REALLOC_SIZE_232, FALSE);
-    guint    i;
+    guint i;
+
+    if (strbuf->len == 0) {
+        /* preallocate a large buffer... */
+        nm_str_buf_maybe_expand(strbuf, NM_UTILS_GET_NEXT_REALLOC_SIZE_232, FALSE);
+    } else
+        nm_str_buf_reset(strbuf);
 
     for (i = 0; i < fields->len; i++) {
         const AuditField *field = fields->pdata[i];
@@ -122,7 +127,7 @@ build_message(GPtrArray *fields, AuditBackend backend)
         if (!NM_FLAGS_ANY(field->backends, backend))
             continue;
 
-        nm_str_buf_append_required_delimiter(&strbuf, ' ');
+        nm_str_buf_append_required_delimiter(strbuf, ' ');
 
         if (field->value_type == NM_VALUE_TYPE_STRING) {
             const char *str = field->value.v_string;
@@ -133,19 +138,19 @@ build_message(GPtrArray *fields, AuditBackend backend)
                     gs_free char *value = NULL;
 
                     value = audit_encode_nv_string(field->name, str, 0);
-                    nm_str_buf_append(&strbuf, value);
+                    nm_str_buf_append(strbuf, value);
                 } else
-                    nm_str_buf_append_printf(&strbuf, "%s=%s", field->name, str);
+                    nm_str_buf_append_printf(strbuf, "%s=%s", field->name, str);
                 continue;
             }
 #endif /* HAVE_LIBAUDIT */
 
-            nm_str_buf_append_printf(&strbuf, "%s=\"%s\"", field->name, str);
+            nm_str_buf_append_printf(strbuf, "%s=\"%s\"", field->name, str);
             continue;
         }
 
         if (field->value_type == NM_VALUE_TYPE_UINT64) {
-            nm_str_buf_append_printf(&strbuf,
+            nm_str_buf_append_printf(strbuf,
                                      "%s=%" G_GUINT64_FORMAT,
                                      field->name,
                                      field->value.v_uint64);
@@ -155,7 +160,7 @@ build_message(GPtrArray *fields, AuditBackend backend)
         g_return_val_if_reached(NULL);
     }
 
-    return nm_str_buf_finalize(&strbuf, NULL);
+    return nm_str_buf_get_str(strbuf);
 }
 
 static void
@@ -166,10 +171,10 @@ nm_audit_log(NMAuditManager *self,
              const char *    func,
              gboolean        success)
 {
+    nm_auto_str_buf NMStrBuf strbuf = NM_STR_BUF_INIT(0, FALSE);
 #if HAVE_LIBAUDIT
     NMAuditManagerPrivate *priv;
 #endif
-    char *msg;
 
     g_return_if_fail(NM_IS_AUDIT_MANAGER(self));
 
@@ -177,14 +182,17 @@ nm_audit_log(NMAuditManager *self,
     priv = NM_AUDIT_MANAGER_GET_PRIVATE(self);
 
     if (priv->auditd_fd >= 0) {
-        msg = build_message(fields, BACKEND_AUDITD);
-        audit_log_user_message(priv->auditd_fd, AUDIT_USYS_CONFIG, msg, NULL, NULL, NULL, success);
-        g_free(msg);
+        audit_log_user_message(priv->auditd_fd,
+                               AUDIT_USYS_CONFIG,
+                               build_message(&strbuf, BACKEND_AUDITD, fields),
+                               NULL,
+                               NULL,
+                               NULL,
+                               success);
     }
 #endif
 
     if (nm_logging_enabled(AUDIT_LOG_LEVEL, LOGD_AUDIT)) {
-        msg = build_message(fields, BACKEND_LOG);
         _nm_log_full(file,
                      line,
                      func,
@@ -196,8 +204,7 @@ nm_audit_log(NMAuditManager *self,
                      NULL,
                      "%s%s",
                      _NMLOG_PREFIX_NAME ": ",
-                     msg);
-        g_free(msg);
+                     build_message(&strbuf, BACKEND_LOG, fields));
     }
 }