diff --git a/include/haproxy/proxy-t.h b/include/haproxy/proxy-t.h
index 08ec3ec00..3dfa4d818 100644
--- a/include/haproxy/proxy-t.h
+++ b/include/haproxy/proxy-t.h
@@ -427,18 +427,6 @@ struct proxy {
 		struct arg_list args;           /* sample arg list that need to be resolved */
 		unsigned int refcount;          /* refcount on this proxy (only used for default proxy for now) */
 		struct ebpt_node by_name;       /* proxies are stored sorted by name here */
-		char *logformat_string;		/* log format string */
-		char *lfs_file;                 /* file name where the logformat string appears (strdup) */
-		int   lfs_line;                 /* file name where the logformat string appears */
-		int   uif_line;                 /* file name where the unique-id-format string appears */
-		char *uif_file;                 /* file name where the unique-id-format string appears (strdup) */
-		char *uniqueid_format_string;	/* unique-id format string */
-		char *logformat_sd_string;	/* log format string for the RFC5424 structured-data part */
-		char *lfsd_file;		/* file name where the structured-data logformat string for RFC5424 appears (strdup) */
-		int  lfsd_line;			/* file name where the structured-data logformat string for RFC5424 appears */
-		char *error_logformat_string;
-		char *elfs_file;
-		int elfs_line;
 		struct list lf_checks;          /* list of logformats found in the proxy section that needs to be checked during postparse */
 	} conf;					/* config information */
 	struct http_ext *http_ext;	        /* http ext options */
diff --git a/src/cfgparse-listen.c b/src/cfgparse-listen.c
index a97b1e55d..c4b266e3e 100644
--- a/src/cfgparse-listen.c
+++ b/src/cfgparse-listen.c
@@ -2096,33 +2096,27 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 				if (alertif_too_many_args_idx(1, 1, file, linenum, args, &err_code))
 					goto out;
 			}
-			if (curproxy->conf.logformat_string && curproxy->cap & PR_CAP_DEF) {
+			if (curproxy->logformat.str && curproxy->cap & PR_CAP_DEF) {
 				char *oldlogformat = "log-format";
 				char *clflogformat = "";
 
-				if (curproxy->conf.logformat_string == default_http_log_format)
+				if (curproxy->logformat.str == default_http_log_format)
 					oldlogformat = "option httplog";
-				else if (curproxy->conf.logformat_string == default_tcp_log_format)
+				else if (curproxy->logformat.str == default_tcp_log_format)
 					oldlogformat = "option tcplog";
-				else if (curproxy->conf.logformat_string == clf_http_log_format)
+				else if (curproxy->logformat.str == clf_http_log_format)
 					oldlogformat = "option httplog clf";
-				else if (curproxy->conf.logformat_string == default_https_log_format)
+				else if (curproxy->logformat.str == default_https_log_format)
 					oldlogformat = "option httpslog";
 				if (logformat == clf_http_log_format)
 					clflogformat = " clf";
 				ha_warning("parsing [%s:%d]: 'option httplog%s' overrides previous '%s' in 'defaults' section.\n",
 					   file, linenum, clflogformat, oldlogformat);
 			}
-			if (curproxy->conf.logformat_string != default_http_log_format &&
-			    curproxy->conf.logformat_string != default_tcp_log_format &&
-			    curproxy->conf.logformat_string != clf_http_log_format &&
-			    curproxy->conf.logformat_string != default_https_log_format)
-				free(curproxy->conf.logformat_string);
-			curproxy->conf.logformat_string = logformat;
-
-			free(curproxy->conf.lfs_file);
-			curproxy->conf.lfs_file = strdup(curproxy->conf.args.file);
-			curproxy->conf.lfs_line = curproxy->conf.args.line;
+			lf_expr_deinit(&curproxy->logformat);
+			curproxy->logformat.str = logformat;
+			curproxy->logformat.conf.file = strdup(curproxy->conf.args.file);
+			curproxy->logformat.conf.line = curproxy->conf.args.line;
 
 			if (!(curproxy->cap & PR_CAP_DEF) && !(curproxy->cap & PR_CAP_FE)) {
 				ha_warning("parsing [%s:%d] : backend '%s' : 'option httplog' directive is ignored in backends.\n",
@@ -2131,31 +2125,25 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			}
 		}
 		else if (strcmp(args[1], "tcplog") == 0) {
-			if (curproxy->conf.logformat_string && curproxy->cap & PR_CAP_DEF) {
+			if (curproxy->logformat.str && curproxy->cap & PR_CAP_DEF) {
 				char *oldlogformat = "log-format";
 
-				if (curproxy->conf.logformat_string == default_http_log_format)
+				if (curproxy->logformat.str == default_http_log_format)
 					oldlogformat = "option httplog";
-				else if (curproxy->conf.logformat_string == default_tcp_log_format)
+				else if (curproxy->logformat.str == default_tcp_log_format)
 					oldlogformat = "option tcplog";
-				else if (curproxy->conf.logformat_string == clf_http_log_format)
+				else if (curproxy->logformat.str == clf_http_log_format)
 					oldlogformat = "option httplog clf";
-				else if (curproxy->conf.logformat_string == default_https_log_format)
+				else if (curproxy->logformat.str == default_https_log_format)
 					oldlogformat = "option httpslog";
 				ha_warning("parsing [%s:%d]: 'option tcplog' overrides previous '%s' in 'defaults' section.\n",
 					   file, linenum, oldlogformat);
 			}
 			/* generate a detailed TCP log */
-			if (curproxy->conf.logformat_string != default_http_log_format &&
-			    curproxy->conf.logformat_string != default_tcp_log_format &&
-			    curproxy->conf.logformat_string != clf_http_log_format &&
-			    curproxy->conf.logformat_string != default_https_log_format)
-				free(curproxy->conf.logformat_string);
-			curproxy->conf.logformat_string = default_tcp_log_format;
-
-			free(curproxy->conf.lfs_file);
-			curproxy->conf.lfs_file = strdup(curproxy->conf.args.file);
-			curproxy->conf.lfs_line = curproxy->conf.args.line;
+			lf_expr_deinit(&curproxy->logformat);
+			curproxy->logformat.str = default_tcp_log_format;
+			curproxy->logformat.conf.file = strdup(curproxy->conf.args.file);
+			curproxy->logformat.conf.line = curproxy->conf.args.line;
 
 			if (alertif_too_many_args_idx(0, 1, file, linenum, args, &err_code))
 				goto out;
@@ -2170,30 +2158,24 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			char *logformat;
 			/* generate a complete HTTP log */
 			logformat = default_https_log_format;
-			if (curproxy->conf.logformat_string && curproxy->cap & PR_CAP_DEF) {
+			if (curproxy->logformat.str && curproxy->cap & PR_CAP_DEF) {
 				char *oldlogformat = "log-format";
 
-				if (curproxy->conf.logformat_string == default_http_log_format)
+				if (curproxy->logformat.str == default_http_log_format)
 					oldlogformat = "option httplog";
-				else if (curproxy->conf.logformat_string == default_tcp_log_format)
+				else if (curproxy->logformat.str == default_tcp_log_format)
 					oldlogformat = "option tcplog";
-				else if (curproxy->conf.logformat_string == clf_http_log_format)
+				else if (curproxy->logformat.str == clf_http_log_format)
 					oldlogformat = "option httplog clf";
-				else if (curproxy->conf.logformat_string == default_https_log_format)
+				else if (curproxy->logformat.str == default_https_log_format)
 					oldlogformat = "option httpslog";
 				ha_warning("parsing [%s:%d]: 'option httplog' overrides previous '%s' in 'defaults' section.\n",
 					   file, linenum, oldlogformat);
 			}
-			if (curproxy->conf.logformat_string != default_http_log_format &&
-			    curproxy->conf.logformat_string != default_tcp_log_format &&
-			    curproxy->conf.logformat_string != clf_http_log_format &&
-			    curproxy->conf.logformat_string != default_https_log_format)
-				free(curproxy->conf.logformat_string);
-			curproxy->conf.logformat_string = logformat;
-
-			free(curproxy->conf.lfs_file);
-			curproxy->conf.lfs_file = strdup(curproxy->conf.args.file);
-			curproxy->conf.lfs_line = curproxy->conf.args.line;
+			lf_expr_deinit(&curproxy->logformat);
+			curproxy->logformat.str = logformat;
+			curproxy->logformat.conf.file = strdup(curproxy->conf.args.file);
+			curproxy->logformat.conf.line = curproxy->conf.args.line;
 
 			if (!(curproxy->cap & PR_CAP_DEF) && !(curproxy->cap & PR_CAP_FE)) {
 				ha_warning("parsing [%s:%d] : backend '%s' : 'option httpslog' directive is ignored in backends.\n",
@@ -2591,14 +2573,12 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			err_code |= ERR_ALERT | ERR_FATAL;
 			goto out;
 		}
-		free(curproxy->conf.uniqueid_format_string);
-		curproxy->conf.uniqueid_format_string = strdup(args[1]);
-		if (!curproxy->conf.uniqueid_format_string)
+		lf_expr_deinit(&curproxy->format_unique_id);
+		curproxy->format_unique_id.str = strdup(args[1]);
+		if (!curproxy->format_unique_id.str)
 			goto alloc_error;
-
-		free(curproxy->conf.uif_file);
-		curproxy->conf.uif_file = strdup(curproxy->conf.args.file);
-		curproxy->conf.uif_line = curproxy->conf.args.line;
+		curproxy->format_unique_id.conf.file = strdup(curproxy->conf.args.file);
+		curproxy->format_unique_id.conf.line = curproxy->conf.args.line;
 	}
 
 	else if (strcmp(args[0], "unique-id-header") == 0) {
@@ -2630,32 +2610,26 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			err_code |= ERR_ALERT | ERR_FATAL;
 			goto out;
 		}
-		if (curproxy->conf.logformat_string && curproxy->cap & PR_CAP_DEF) {
+		if (curproxy->logformat.str && curproxy->cap & PR_CAP_DEF) {
 			char *oldlogformat = "log-format";
 
-			if (curproxy->conf.logformat_string == default_http_log_format)
+			if (curproxy->logformat.str == default_http_log_format)
 				oldlogformat = "option httplog";
-			else if (curproxy->conf.logformat_string == default_tcp_log_format)
+			else if (curproxy->logformat.str == default_tcp_log_format)
 				oldlogformat = "option tcplog";
-			else if (curproxy->conf.logformat_string == clf_http_log_format)
+			else if (curproxy->logformat.str == clf_http_log_format)
 				oldlogformat = "option httplog clf";
-			else if (curproxy->conf.logformat_string == default_https_log_format)
+			else if (curproxy->logformat.str == default_https_log_format)
 				oldlogformat = "option httpslog";
 			ha_warning("parsing [%s:%d]: 'log-format' overrides previous '%s' in 'defaults' section.\n",
 				   file, linenum, oldlogformat);
 		}
-		if (curproxy->conf.logformat_string != default_http_log_format &&
-		    curproxy->conf.logformat_string != default_tcp_log_format &&
-		    curproxy->conf.logformat_string != clf_http_log_format &&
-		    curproxy->conf.logformat_string != default_https_log_format)
-			free(curproxy->conf.logformat_string);
-		curproxy->conf.logformat_string = strdup(args[1]);
-		if (!curproxy->conf.logformat_string)
+		lf_expr_deinit(&curproxy->logformat);
+		curproxy->logformat.str = strdup(args[1]);
+		if (!curproxy->logformat.str)
 			goto alloc_error;
-
-		free(curproxy->conf.lfs_file);
-		curproxy->conf.lfs_file = strdup(curproxy->conf.args.file);
-		curproxy->conf.lfs_line = curproxy->conf.args.line;
+		curproxy->logformat.conf.file = strdup(curproxy->conf.args.file);
+		curproxy->logformat.conf.line = curproxy->conf.args.line;
 
 		/* get a chance to improve log-format error reporting by
 		 * reporting the correct line-number when possible.
@@ -2678,15 +2652,12 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			goto out;
 		}
 
-		if (curproxy->conf.logformat_sd_string != default_rfc5424_sd_log_format)
-			free(curproxy->conf.logformat_sd_string);
-		curproxy->conf.logformat_sd_string = strdup(args[1]);
-		if (!curproxy->conf.logformat_sd_string)
+		lf_expr_deinit(&curproxy->logformat_sd);
+		curproxy->logformat_sd.str = strdup(args[1]);
+		if (!curproxy->logformat_sd.str)
 			goto alloc_error;
-
-		free(curproxy->conf.lfsd_file);
-		curproxy->conf.lfsd_file = strdup(curproxy->conf.args.file);
-		curproxy->conf.lfsd_line = curproxy->conf.args.line;
+		curproxy->logformat_sd.conf.file = strdup(curproxy->conf.args.file);
+		curproxy->logformat_sd.conf.line = curproxy->conf.args.line;
 
 		/* get a chance to improve log-format-sd error reporting by
 		 * reporting the correct line-number when possible.
@@ -2708,18 +2679,17 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			err_code |= ERR_ALERT | ERR_FATAL;
 			goto out;
 		}
-		if (curproxy->conf.error_logformat_string && curproxy->cap & PR_CAP_DEF) {
+		if (curproxy->logformat_error.str && curproxy->cap & PR_CAP_DEF) {
 			ha_warning("parsing [%s:%d]: 'error-log-format' overrides previous 'error-log-format' in 'defaults' section.\n",
 				   file, linenum);
 		}
-		free(curproxy->conf.error_logformat_string);
-		curproxy->conf.error_logformat_string = strdup(args[1]);
-		if (!curproxy->conf.error_logformat_string)
+		lf_expr_deinit(&curproxy->logformat_error);
+		curproxy->logformat_error.str = strdup(args[1]);
+		if (!curproxy->logformat_error.str)
 			goto alloc_error;
 
-		free(curproxy->conf.elfs_file);
-		curproxy->conf.elfs_file = strdup(curproxy->conf.args.file);
-		curproxy->conf.elfs_line = curproxy->conf.args.line;
+		curproxy->logformat_error.conf.file = strdup(curproxy->conf.args.file);
+		curproxy->logformat_error.conf.line = curproxy->conf.args.line;;
 
 		/* get a chance to improve log-format error reporting by
 		 * reporting the correct line-number when possible.
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 2df386e2c..15fca551b 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -3382,9 +3382,9 @@ int check_config_validity()
 		/* check whether we have a logger that uses RFC5424 log format */
 		list_for_each_entry(tmplogger, &curproxy->loggers, list) {
 			if (tmplogger->format == LOG_FORMAT_RFC5424) {
-				if (!curproxy->conf.logformat_sd_string) {
+				if (!curproxy->logformat_sd.str) {
 					/* set the default logformat_sd_string */
-					curproxy->conf.logformat_sd_string = default_rfc5424_sd_log_format;
+					curproxy->logformat_sd.str = default_rfc5424_sd_log_format;
 				}
 				break;
 			}
@@ -3392,31 +3392,21 @@ int check_config_validity()
 
 		/* compile the log format */
 		if (!(curproxy->cap & PR_CAP_FE)) {
-			if (curproxy->conf.logformat_string != default_http_log_format &&
-			    curproxy->conf.logformat_string != default_tcp_log_format &&
-			    curproxy->conf.logformat_string != clf_http_log_format)
-				free(curproxy->conf.logformat_string);
-			curproxy->conf.logformat_string = NULL;
-			ha_free(&curproxy->conf.lfs_file);
-			curproxy->conf.lfs_line = 0;
-
-			if (curproxy->conf.logformat_sd_string != default_rfc5424_sd_log_format)
-				free(curproxy->conf.logformat_sd_string);
-			curproxy->conf.logformat_sd_string = NULL;
-			ha_free(&curproxy->conf.lfsd_file);
-			curproxy->conf.lfsd_line = 0;
+			lf_expr_deinit(&curproxy->logformat);
+			lf_expr_deinit(&curproxy->logformat_sd);
 		}
 
-		if (curproxy->conf.logformat_string) {
+		if (curproxy->logformat.str) {
 			curproxy->conf.args.ctx = ARGC_LOG;
-			curproxy->conf.args.file = curproxy->conf.lfs_file;
-			curproxy->conf.args.line = curproxy->conf.lfs_line;
+			curproxy->conf.args.file = curproxy->logformat.conf.file;
+			curproxy->conf.args.line = curproxy->logformat.conf.line;
 			err = NULL;
-			if (!parse_logformat_string(curproxy->conf.logformat_string, curproxy, &curproxy->logformat,
+			if (!lf_expr_compile(&curproxy->logformat, &curproxy->conf.args,
 			                            LOG_OPT_MANDATORY|LOG_OPT_MERGE_SPACES,
-			                            SMP_VAL_FE_LOG_END, &err)) {
+			                            SMP_VAL_FE_LOG_END, &err) ||
+			    !lf_expr_postcheck(&curproxy->logformat, curproxy, &err)) {
 				ha_alert("Parsing [%s:%d]: failed to parse log-format : %s.\n",
-					 curproxy->conf.lfs_file, curproxy->conf.lfs_line, err);
+					 curproxy->logformat.conf.file, curproxy->logformat.conf.line, err);
 				free(err);
 				cfgerr++;
 			}
@@ -3424,21 +3414,18 @@ int check_config_validity()
 			curproxy->conf.args.line = 0;
 		}
 
-		if (curproxy->conf.logformat_sd_string) {
+		if (curproxy->logformat_sd.str) {
 			curproxy->conf.args.ctx = ARGC_LOGSD;
-			curproxy->conf.args.file = curproxy->conf.lfsd_file;
-			curproxy->conf.args.line = curproxy->conf.lfsd_line;
+			curproxy->conf.args.file = curproxy->logformat_sd.conf.file;
+			curproxy->conf.args.line = curproxy->logformat_sd.conf.line;
 			err = NULL;
-			if (!parse_logformat_string(curproxy->conf.logformat_sd_string, curproxy, &curproxy->logformat_sd,
+			if (!lf_expr_compile(&curproxy->logformat_sd, &curproxy->conf.args,
 			                            LOG_OPT_MANDATORY|LOG_OPT_MERGE_SPACES,
-			                            SMP_VAL_FE_LOG_END, &err)) {
+			                            SMP_VAL_FE_LOG_END, &err) ||
+			    !add_to_logformat_list(NULL, NULL, LF_SEPARATOR, &curproxy->logformat_sd, &err) ||
+			    !lf_expr_postcheck(&curproxy->logformat_sd, curproxy, &err)) {
 				ha_alert("Parsing [%s:%d]: failed to parse log-format-sd : %s.\n",
-					 curproxy->conf.lfsd_file, curproxy->conf.lfsd_line, err);
-				free(err);
-				cfgerr++;
-			} else if (!add_to_logformat_list(NULL, NULL, LF_SEPARATOR, &curproxy->logformat_sd, &err)) {
-				ha_alert("Parsing [%s:%d]: failed to parse log-format-sd : %s.\n",
-					 curproxy->conf.lfsd_file, curproxy->conf.lfsd_line, err);
+					 curproxy->logformat_sd.conf.file, curproxy->logformat_sd.conf.line, err);
 				free(err);
 				cfgerr++;
 			}
@@ -3446,21 +3433,22 @@ int check_config_validity()
 			curproxy->conf.args.line = 0;
 		}
 
-		if (curproxy->conf.uniqueid_format_string) {
+		if (curproxy->format_unique_id.str) {
 			int where = 0;
 
 			curproxy->conf.args.ctx = ARGC_UIF;
-			curproxy->conf.args.file = curproxy->conf.uif_file;
-			curproxy->conf.args.line = curproxy->conf.uif_line;
+			curproxy->conf.args.file = curproxy->format_unique_id.conf.file;
+			curproxy->conf.args.line = curproxy->format_unique_id.conf.line;
 			err = NULL;
 			if (curproxy->cap & PR_CAP_FE)
 				where |= SMP_VAL_FE_HRQ_HDR;
 			if (curproxy->cap & PR_CAP_BE)
 				where |= SMP_VAL_BE_HRQ_HDR;
-			if (!parse_logformat_string(curproxy->conf.uniqueid_format_string, curproxy, &curproxy->format_unique_id,
-			                            LOG_OPT_HTTP|LOG_OPT_MERGE_SPACES, where, &err)) {
+			if (!lf_expr_compile(&curproxy->format_unique_id, &curproxy->conf.args,
+			                            LOG_OPT_HTTP|LOG_OPT_MERGE_SPACES, where, &err) ||
+			    !lf_expr_postcheck(&curproxy->format_unique_id, curproxy, &err)) {
 				ha_alert("Parsing [%s:%d]: failed to parse unique-id : %s.\n",
-					 curproxy->conf.uif_file, curproxy->conf.uif_line, err);
+					 curproxy->format_unique_id.conf.file, curproxy->format_unique_id.conf.line, err);
 				free(err);
 				cfgerr++;
 			}
@@ -3468,16 +3456,17 @@ int check_config_validity()
 			curproxy->conf.args.line = 0;
 		}
 
-		if (curproxy->conf.error_logformat_string) {
+		if (curproxy->logformat_error.str) {
 			curproxy->conf.args.ctx = ARGC_LOG;
-			curproxy->conf.args.file = curproxy->conf.elfs_file;
-			curproxy->conf.args.line = curproxy->conf.elfs_line;
+			curproxy->conf.args.file = curproxy->logformat_error.conf.file;
+			curproxy->conf.args.line = curproxy->logformat_error.conf.line;
 			err = NULL;
-			if (!parse_logformat_string(curproxy->conf.error_logformat_string, curproxy, &curproxy->logformat_error,
+			if (!lf_expr_compile(&curproxy->logformat_error, &curproxy->conf.args,
 			                            LOG_OPT_MANDATORY|LOG_OPT_MERGE_SPACES,
-			                            SMP_VAL_FE_LOG_END, &err)) {
+			                            SMP_VAL_FE_LOG_END, &err) ||
+			    !lf_expr_postcheck(&curproxy->logformat_error, curproxy, &err)) {
 				ha_alert("Parsing [%s:%d]: failed to parse error-log-format : %s.\n",
-					 curproxy->conf.elfs_file, curproxy->conf.elfs_line, err);
+					 curproxy->logformat_error.conf.file, curproxy->logformat_error.conf.line, err);
 				free(err);
 				cfgerr++;
 			}
diff --git a/src/http_client.c b/src/http_client.c
index d8d9654a2..96ddd0378 100644
--- a/src/http_client.c
+++ b/src/http_client.c
@@ -1219,7 +1219,8 @@ struct proxy *httpclient_create_proxy(const char *id)
 	px->timeout.connect = httpclient_timeout_connect;
 	px->timeout.client = TICK_ETERNITY;
 	/* The HTTP Client use the "option httplog" with the global loggers */
-	px->conf.logformat_string = httpclient_log_format;
+	px->logformat.str = httpclient_log_format;
+	px->logformat.conf.file = strdup("httpclient");
 	px->http_needed = 1;
 
 	/* clear HTTP server */
@@ -1335,34 +1336,13 @@ struct proxy *httpclient_create_proxy(const char *id)
  */
 static int httpclient_precheck()
 {
-	int err_code = ERR_NONE;
-	char *errmsg = NULL;
-
 	/* initialize the default httpclient_proxy which is used for the CLI and the lua */
 
 	httpclient_proxy = httpclient_create_proxy("<HTTPCLIENT>");
 	if (!httpclient_proxy)
 		return ERR_RETRYABLE;
-	if (httpclient_proxy->conf.logformat_string) {
-		httpclient_proxy->conf.args.ctx = ARGC_LOG;
-		if (!parse_logformat_string(httpclient_proxy->conf.logformat_string,
-		                            httpclient_proxy, &httpclient_proxy->logformat,
-					    LOG_OPT_MANDATORY|LOG_OPT_MERGE_SPACES,
-					    SMP_VAL_FE_LOG_END, &errmsg)) {
-			memprintf(&errmsg, "failed to parse log-format : %s.", errmsg);
-			err_code |= ERR_ALERT | ERR_FATAL;
-			goto err;
-		}
-		httpclient_proxy->conf.args.file = NULL;
-		httpclient_proxy->conf.args.line = 0;
-	}
 
- err:
-	if (err_code & ERR_CODE) {
-		ha_alert("httpclient: failed to initialize: %s\n", errmsg);
-		free(errmsg);
-	}
-	return err_code;
+	return ERR_NONE;
 }
 
 /* Initialize the logs for every proxy dedicated to the httpclient */
diff --git a/src/log.c b/src/log.c
index 8b414cc58..13d23351b 100644
--- a/src/log.c
+++ b/src/log.c
@@ -272,6 +272,36 @@ char *log_format = NULL;
  */
 char default_rfc5424_sd_log_format[] = "- ";
 
+/* returns true if the input logformat string is one of the default ones declared
+ * above
+ */
+static inline int logformat_str_isdefault(const char *str)
+{
+	return str == httpclient_log_format ||
+	       str == default_http_log_format ||
+	       str == default_https_log_format ||
+	       str == clf_http_log_format ||
+	       str == default_tcp_log_format ||
+	       str == default_rfc5424_sd_log_format;
+}
+
+/* free logformat str if it is not a default (static) one */
+static inline void logformat_str_free(char **str)
+{
+	if (!logformat_str_isdefault(*str))
+		ha_free(str);
+}
+
+/* duplicate and return logformat str if it is not a default (static)
+ * one, else return the original one
+ */
+static inline char *logformat_str_dup(char *str)
+{
+	if (logformat_str_isdefault(str))
+		return str;
+	return strdup(str);
+}
+
 /* total number of dropped logs */
 unsigned int dropped_logs = 0;
 
@@ -549,7 +579,7 @@ static int add_sample_to_logformat_list(char *text, char *name, int name_len, in
 int lf_expr_compile(struct lf_expr *lf_expr,
                     struct arg_list *al, int options, int cap, char **err)
 {
-	char *fmt = lf_expr->str; /* will be freed */
+	char *fmt = lf_expr->str; /* will be freed unless default */
 	char *sp, *str, *backfmt; /* start pointer for text parts */
 	char *arg = NULL; /* start pointer for args */
 	char *tag = NULL; /* start pointer for tags */
@@ -758,12 +788,12 @@ int lf_expr_compile(struct lf_expr *lf_expr,
 		memprintf(err, "truncated line after '%s'", tag ? tag : arg ? arg : "%");
 		goto fail;
 	}
-	ha_free(&fmt);
+	logformat_str_free(&fmt);
 	ha_free(&backfmt);
 
 	return 1;
  fail:
-	ha_free(&fmt);
+	logformat_str_free(&fmt);
 	ha_free(&backfmt);
 	return 0;
 }
@@ -2768,7 +2798,7 @@ void lf_expr_deinit(struct lf_expr *expr)
 	if ((expr->flags & LF_FL_COMPILED))
 		free_logformat_list(&expr->nodes);
 	else
-		free(expr->str);
+		logformat_str_free(&expr->str);
 	free(expr->conf.file);
 	/* remove from parent list (if any) */
 	LIST_DEL_INIT(&expr->list);
@@ -2819,7 +2849,7 @@ int lf_expr_dup(const struct lf_expr *orig, struct lf_expr *dest)
 	BUG_ON((orig->flags & LF_FL_COMPILED));
 	lf_expr_deinit(dest);
 	if (orig->str) {
-		dest->str = strdup(orig->str);
+		dest->str = logformat_str_dup(orig->str);
 		if (!dest->str)
 			goto error;
 	}
diff --git a/src/proxy.c b/src/proxy.c
index 20fc15601..2be87912f 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -223,27 +223,10 @@ void free_proxy(struct proxy *p)
 #if defined(CONFIG_HAP_TRANSPARENT)
 	free(p->conn_src.bind_hdr_name);
 #endif
-	if (p->conf.logformat_string != default_http_log_format &&
-	    p->conf.logformat_string != default_tcp_log_format &&
-	    p->conf.logformat_string != clf_http_log_format &&
-	    p->conf.logformat_string != default_https_log_format &&
-	    p->conf.logformat_string != httpclient_log_format)
-		free(p->conf.logformat_string);
-
-	free(p->conf.lfs_file);
-	free(p->conf.uniqueid_format_string);
 	istfree(&p->header_unique_id);
-	free(p->conf.uif_file);
 	if ((p->lbprm.algo & BE_LB_LKUP) == BE_LB_LKUP_MAP)
 		free(p->lbprm.map.srv);
 
-	if (p->conf.logformat_sd_string != default_rfc5424_sd_log_format)
-		free(p->conf.logformat_sd_string);
-	free(p->conf.lfsd_file);
-
-	free(p->conf.error_logformat_string);
-	free(p->conf.elfs_file);
-
 	list_for_each_entry_safe(cond, condb, &p->mon_fail_cond, list) {
 		LIST_DELETE(&cond->list);
 		free_acl_cond(cond);
@@ -1279,19 +1262,19 @@ int proxy_cfg_ensure_no_http(struct proxy *curproxy)
 		ha_warning("Layer 7 hash not possible for %s '%s' (needs 'mode http'). Falling back to round robin.\n",
 			   proxy_type_str(curproxy), curproxy->id);
 	}
-	if (curproxy->conf.logformat_string == default_http_log_format ||
-	    curproxy->conf.logformat_string == clf_http_log_format) {
+	if (curproxy->logformat.str == default_http_log_format ||
+	    curproxy->logformat.str == clf_http_log_format) {
 		/* Note: we don't change the directive's file:line number */
-		curproxy->conf.logformat_string = default_tcp_log_format;
+		curproxy->logformat.str = default_tcp_log_format;
 		ha_warning("parsing [%s:%d] : 'option httplog' not usable with %s '%s' (needs 'mode http'). Falling back to 'option tcplog'.\n",
-			   curproxy->conf.lfs_file, curproxy->conf.lfs_line,
+			   curproxy->logformat.conf.file, curproxy->logformat.conf.line,
 			   proxy_type_str(curproxy), curproxy->id);
 	}
-	else if (curproxy->conf.logformat_string == default_https_log_format) {
+	else if (curproxy->logformat.str == default_https_log_format) {
 		/* Note: we don't change the directive's file:line number */
-		curproxy->conf.logformat_string = default_tcp_log_format;
+		curproxy->logformat.str = default_tcp_log_format;
 		ha_warning("parsing [%s:%d] : 'option httpslog' not usable with %s '%s' (needs 'mode http'). Falling back to 'option tcplog'.\n",
-			   curproxy->conf.lfs_file, curproxy->conf.lfs_line,
+			   curproxy->logformat.conf.file, curproxy->logformat.conf.line,
 			   proxy_type_str(curproxy), curproxy->id);
 	}
 
@@ -1342,10 +1325,6 @@ void init_new_proxy(struct proxy *p)
 	LIST_INIT(&p->tcp_req.l5_rules);
 	MT_LIST_INIT(&p->listener_queue);
 	LIST_INIT(&p->loggers);
-	lf_expr_init(&p->logformat);
-	lf_expr_init(&p->logformat_sd);
-	lf_expr_init(&p->format_unique_id);
-	lf_expr_init(&p->logformat_error);
 	LIST_INIT(&p->conf.bind);
 	LIST_INIT(&p->conf.listeners);
 	LIST_INIT(&p->conf.errors);
@@ -1395,6 +1374,11 @@ void proxy_preset_defaults(struct proxy *defproxy)
 
 	srv_settings_init(&defproxy->defsrv);
 
+	lf_expr_init(&defproxy->logformat);
+	lf_expr_init(&defproxy->logformat_sd);
+	lf_expr_init(&defproxy->format_unique_id);
+	lf_expr_init(&defproxy->logformat_error);
+
 	defproxy->email_alert.level = LOG_ALERT;
 	defproxy->load_server_state_from_file = PR_SRV_STATE_FILE_UNSPEC;
 
@@ -1465,27 +1449,16 @@ void proxy_free_defaults(struct proxy *defproxy)
 		h = h_next;
 	}
 
-	if (defproxy->conf.logformat_string != default_http_log_format &&
-	    defproxy->conf.logformat_string != default_tcp_log_format &&
-	    defproxy->conf.logformat_string != clf_http_log_format &&
-	    defproxy->conf.logformat_string != default_https_log_format) {
-		ha_free(&defproxy->conf.logformat_string);
-	}
-
-	if (defproxy->conf.logformat_sd_string != default_rfc5424_sd_log_format)
-		ha_free(&defproxy->conf.logformat_sd_string);
+	lf_expr_deinit(&defproxy->logformat);
+	lf_expr_deinit(&defproxy->logformat_sd);
+	lf_expr_deinit(&defproxy->logformat_error);
+	lf_expr_deinit(&defproxy->format_unique_id);
 
 	list_for_each_entry_safe(log, logb, &defproxy->loggers, list) {
 		LIST_DEL_INIT(&log->list);
 		free_logger(log);
 	}
 
-	ha_free(&defproxy->conf.uniqueid_format_string);
-	ha_free(&defproxy->conf.error_logformat_string);
-	ha_free(&defproxy->conf.lfs_file);
-	ha_free(&defproxy->conf.lfsd_file);
-	ha_free(&defproxy->conf.uif_file);
-	ha_free(&defproxy->conf.elfs_file);
 	chunk_destroy(&defproxy->log_tag);
 
 	free_email_alert(defproxy);
@@ -1726,39 +1699,9 @@ static int proxy_defproxy_cpy(struct proxy *curproxy, const struct proxy *defpro
 		if (defproxy->defbe.name)
 			curproxy->defbe.name = strdup(defproxy->defbe.name);
 
-		/* get either a pointer to the logformat string or a copy of it */
-		curproxy->conf.logformat_string = defproxy->conf.logformat_string;
-		if (curproxy->conf.logformat_string &&
-		    curproxy->conf.logformat_string != default_http_log_format &&
-		    curproxy->conf.logformat_string != default_tcp_log_format &&
-		    curproxy->conf.logformat_string != clf_http_log_format &&
-		    curproxy->conf.logformat_string != default_https_log_format)
-			curproxy->conf.logformat_string = strdup(curproxy->conf.logformat_string);
-
-		if (defproxy->conf.lfs_file) {
-			curproxy->conf.lfs_file = strdup(defproxy->conf.lfs_file);
-			curproxy->conf.lfs_line = defproxy->conf.lfs_line;
-		}
-
-		/* get either a pointer to the logformat string for RFC5424 structured-data or a copy of it */
-		curproxy->conf.logformat_sd_string = defproxy->conf.logformat_sd_string;
-		if (curproxy->conf.logformat_sd_string &&
-		    curproxy->conf.logformat_sd_string != default_rfc5424_sd_log_format)
-			curproxy->conf.logformat_sd_string = strdup(curproxy->conf.logformat_sd_string);
-
-		if (defproxy->conf.lfsd_file) {
-			curproxy->conf.lfsd_file = strdup(defproxy->conf.lfsd_file);
-			curproxy->conf.lfsd_line = defproxy->conf.lfsd_line;
-		}
-
-		curproxy->conf.error_logformat_string = defproxy->conf.error_logformat_string;
-		if (curproxy->conf.error_logformat_string)
-			curproxy->conf.error_logformat_string = strdup(curproxy->conf.error_logformat_string);
-
-		if (defproxy->conf.elfs_file) {
-			curproxy->conf.elfs_file = strdup(defproxy->conf.elfs_file);
-			curproxy->conf.elfs_line = defproxy->conf.elfs_line;
-		}
+		lf_expr_dup(&defproxy->logformat, &curproxy->logformat);
+		lf_expr_dup(&defproxy->logformat_sd, &curproxy->logformat_sd);
+		lf_expr_dup(&defproxy->logformat_error, &curproxy->logformat_error);
 	}
 
 	if (curproxy->cap & PR_CAP_BE) {
@@ -1788,17 +1731,10 @@ static int proxy_defproxy_cpy(struct proxy *curproxy, const struct proxy *defpro
 		LIST_APPEND(&curproxy->loggers, &node->list);
 	}
 
-	curproxy->conf.uniqueid_format_string = defproxy->conf.uniqueid_format_string;
-	if (curproxy->conf.uniqueid_format_string)
-		curproxy->conf.uniqueid_format_string = strdup(curproxy->conf.uniqueid_format_string);
+	lf_expr_dup(&defproxy->format_unique_id, &curproxy->format_unique_id);
 
 	chunk_dup(&curproxy->log_tag, &defproxy->log_tag);
 
-	if (defproxy->conf.uif_file) {
-		curproxy->conf.uif_file = strdup(defproxy->conf.uif_file);
-		curproxy->conf.uif_line = defproxy->conf.uif_line;
-	}
-
 	/* copy default header unique id */
 	if (isttest(defproxy->header_unique_id)) {
 		const struct ist copy = istdup(defproxy->header_unique_id);
diff --git a/src/ssl_ocsp.c b/src/ssl_ocsp.c
index 1add6bd00..1b96200ca 100644
--- a/src/ssl_ocsp.c
+++ b/src/ssl_ocsp.c
@@ -1405,7 +1405,7 @@ static int ssl_ocsp_update_precheck()
 	httpclient_ocsp_update_px = httpclient_create_proxy("<OCSP-UPDATE>");
 	if (!httpclient_ocsp_update_px)
 		return ERR_RETRYABLE;
-	httpclient_ocsp_update_px->conf.logformat_string = httpclient_log_format;
+	httpclient_ocsp_update_px->logformat.str = httpclient_log_format;
 	httpclient_ocsp_update_px->options2 |= PR_O2_NOLOGNORM;
 
 	return ERR_NONE;