MEDIUM: proxy: Add a directive to reference an http-errors section in a proxy

It is now possible to import in a proxy, fully or partially, error files
declared in an http-errors section. It may be done using the "errorfiles"
directive, followed by a name and optionally a list of status code. If there is
no status code specified, all error files of the http-errors section are
imported. Otherwise, only error files associated to the listed status code are
imported. For instance :

  http-errors my-errors
      errorfile 400 ...
      errorfile 403 ...
      errorfile 404 ...

  frontend frt
      errorfiles my-errors 403 404  # ==> error 400 not imported

doc/configuration.txt

@@ -52,6 +52,7 @@ Summary
 3.5.      Peers
 3.6.      Mailers
 3.7.      Programs
+3.8.      HTTP-errors
 
 4.    Proxies
 4.1.      Proxy keywords matrix
@@ -2378,6 +2379,45 @@ no option start-on-reload
   program section.
 
 
+3.8. HTTP-errors
+----------------
+
+It is possible to globally declare several groups of HTTP errors, to be
+imported afterwards in any proxy section. Same group may be referenced at
+several places and can be fully or partially imported.
+
+http-errors <name>
+  Create a new http-errors group with the name <name>. It is an independent
+  section that may be referenced by one or more proxies using its name.
+
+errorfile <code> <file>
+  Associate a file contents to an HTTP error code
+
+  Arguments :
+    <code>    is the HTTP status code. Currently, HAProxy is capable of
+              generating codes 200, 400, 403, 404, 405, 408, 410, 425, 429,
+              500, 502, 503, and 504.
+
+    <file>    designates a file containing the full HTTP response. It is
+              recommended to follow the common practice of appending ".http" to
+              the filename so that people do not confuse the response with HTML
+              error pages, and to use absolute paths, since files are read
+              before any chroot is performed.
+
+  Please referrers to "errorfile" keyword in section 4 for details.
+
+  Example:
+    http-errors website-1
+        errorfile 400 /etc/haproxy/errorfiles/site1/400.http
+        errorfile 404 /etc/haproxy/errorfiles/site1/404.http
+        errorfile 408 /dev/null  # work around Chrome pre-connect bug
+
+    http-errors website-2
+        errorfile 400 /etc/haproxy/errorfiles/site2/400.http
+        errorfile 404 /etc/haproxy/errorfiles/site2/404.http
+        errorfile 408 /dev/null  # work around Chrome pre-connect bug
+
+
 4. Proxies
 ----------
 
@@ -2489,6 +2529,7 @@ email-alert myhostname                    X          X         X         X
 email-alert to                            X          X         X         X
 enabled                                   X          X         X         X
 errorfile                                 X          X         X         X
+errorfiles                                X          X         X         X
 errorloc                                  X          X         X         X
 errorloc302                               X          X         X         X
 -- keyword -------------------------- defaults - frontend - listen -- backend -
@@ -3651,6 +3692,34 @@ errorfile <code> <file>
         errorfile 503 /etc/haproxy/errorfiles/503sorry.http
 
 
+errorfiles <name> [<code> ...]
+  Import, fully or partially, the error files defined in the <name> http-errors
+  section.
+  May be used in sections :   defaults | frontend | listen | backend
+                                 yes   |    yes   |   yes  |   yes
+  Arguments :
+    <name>  is the name of an existing http-errors section.
+
+    <code>  is a HTTP status code. Several status code may be listed.
+            Currently, HAProxy is capable of generating codes 200, 400, 403,
+            404, 405, 408, 410, 425, 429, 500, 502, 503, and 504.
+
+  Errors defined in the http-errors section with the name <name> are imported
+  in the current proxy. If no status code is specified, all error files of the
+  http-errors section are imported. Otherwise, only error files associated to
+  the listed status code are imported. Those error files override the already
+  defined custom errors for the proxy. And they may be overridden by following
+  ones. Fonctionnly, it is exactly the same than declaring all error files by
+  hand using "errorfile" directives.
+
+  See also : "errorfile", "errorloc", "errorloc302" , "errorloc303" and section
+             3.8 about http-errors.
+
+  Example :
+        errorfiles generic
+	errorfiles site-1 403 404
+
+
 errorloc <code> <url>
 errorloc302 <code> <url>
   Return an HTTP redirection to a URL instead of errors generated by HAProxy

include/proto/http_htx.h

@@ -53,5 +53,7 @@ struct buffer *http_load_errorfile(const char *file, char **errmsg);
 struct buffer *http_load_errormsg(const char *key, const struct ist msg, char **errmsg);
 struct buffer *http_parse_errorfile(int status, const char *file, char **errmsg);
 struct buffer *http_parse_errorloc(int errloc, int status, const char *url, char **errmsg);
+int proxy_dup_default_conf_errors(struct proxy *curpx, struct proxy *defpx, char **errmsg);
+void proxy_release_conf_errors(struct proxy *px);
 
 #endif /* _PROTO_HTTP_HTX_H */

include/types/proxy.h

@@ -449,6 +449,7 @@ struct proxy {
 		struct eb_root used_server_name; /* list of server names in use */
 		struct list bind;		/* list of bind settings */
 		struct list listeners;		/* list of listeners belonging to this frontend */
+		struct list errors;             /* list of all custom error files */
 		struct arg_list args;           /* sample arg list that need to be resolved */
 		struct ebpt_node by_name;       /* proxies are stored sorted by name here */
 		char *logformat_string;		/* log format string */

src/cfgparse-listen.c

@@ -262,7 +262,11 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 		}
 
 		/* initialize error relocations */
-		memcpy(&curproxy->errmsg, &defproxy.errmsg, sizeof(defproxy.errmsg));
+		if (!proxy_dup_default_conf_errors(curproxy, &defproxy, &errmsg)) {
+			ha_alert("parsing [%s:%d] : proxy '%s' : %s\n", file, linenum, curproxy->id, errmsg);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
 
 		if (curproxy->cap & PR_CAP_FE) {
 			curproxy->maxconn = defproxy.maxconn;
@@ -502,7 +506,7 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 			free(defproxy.conf.logformat_sd_string);
 		free(defproxy.conf.lfsd_file);
 
-		memset(&defproxy.errmsg, 0, sizeof(defproxy.errmsg));
+		proxy_release_conf_errors(&defproxy);
 
 		/* we cannot free uri_auth because it might already be used */
 		init_default_instance();

src/http_htx.c

@@ -32,6 +32,27 @@ struct buffer http_err_chunks[HTTP_ERR_SIZE];
 struct eb_root http_error_messages = EB_ROOT;
 struct list http_errors_list = LIST_HEAD_INIT(http_errors_list);
 
+/* The declaration of an errorfiles/errorfile directives. Used during config
+ * parsing only. */
+struct conf_errors {
+	char type;                                  /* directive type (0: errorfiles, 1: errorfile) */
+	union {
+		struct {
+			int status;                 /* the status code associated to this error */
+			struct buffer *msg;         /* the HTX error message */
+		} errorfile;                        /* describe an "errorfile" directive */
+		struct {
+			char *name;                 /* the http-errors section name */
+			char status[HTTP_ERR_SIZE]; /* list of status to import (0: ignore, 1: implicit import, 2: explicit import) */
+		} errorfiles;                       /* describe an "errorfiles" directive */
+	} info;
+
+	char *file;                                 /* file where the directive appears */
+	int line;                                   /* line where the directive appears */
+
+	struct list list;                           /* next conf_errors */
+};
+
 static int http_update_authority(struct htx *htx, struct htx_sl *sl, const struct ist host);
 static int http_update_host(struct htx *htx, struct htx_sl *sl, const struct ist uri);
 
@@ -1064,8 +1085,10 @@ static int proxy_parse_errorloc(char **args, int section, struct proxy *curpx,
 				  struct proxy *defpx, const char *file, int line,
 				  char **errmsg)
 {
+	struct conf_errors *conf_err;
 	struct buffer *msg;
-	int errloc, status, rc, ret = 0;
+	int errloc, status;
+	int ret = 0;
 
 	if (warnifnotcap(curpx, PR_CAP_FE | PR_CAP_BE, file, line, args[0], NULL)) {
 		ret = 1;
@@ -1087,21 +1110,33 @@ static int proxy_parse_errorloc(char **args, int section, struct proxy *curpx,
 		goto out;
 	}
 
-	rc = http_get_status_idx(status);
+	conf_err = calloc(1, sizeof(*conf_err));
-	curpx->errmsg[rc] = msg;
+	if (!conf_err) {
+		memprintf(errmsg, "%s : out of memory.", args[0]);
+		ret = -1;
+		goto out;
+	}
+	conf_err->type = 1;
+	conf_err->info.errorfile.status = status;
+	conf_err->info.errorfile.msg = msg;
+	conf_err->file = strdup(file);
+	conf_err->line = line;
+	LIST_ADDQ(&curpx->conf.errors, &conf_err->list);
 
   out:
 	return ret;
-}
 
+}
 
 /* Parses the "errorfile" proxy keyword */
 static int proxy_parse_errorfile(char **args, int section, struct proxy *curpx,
 				 struct proxy *defpx, const char *file, int line,
 				 char **errmsg)
 {
+	struct conf_errors *conf_err;
 	struct buffer *msg;
-	int status, rc, ret = 0;
+	int status;
+	int ret = 0;
 
 	if (warnifnotcap(curpx, PR_CAP_FE | PR_CAP_BE, file, line, args[0], NULL)) {
 		ret = 1;
@@ -1122,14 +1157,190 @@ static int proxy_parse_errorfile(char **args, int section, struct proxy *curpx,
 		goto out;
 	}
 
-	rc = http_get_status_idx(status);
+	conf_err = calloc(1, sizeof(*conf_err));
-	curpx->errmsg[rc] = msg;
+	if (!conf_err) {
+		memprintf(errmsg, "%s : out of memory.", args[0]);
+		ret = -1;
+		goto out;
+	}
+	conf_err->type = 1;
+	conf_err->info.errorfile.status = status;
+	conf_err->info.errorfile.msg = msg;
+	conf_err->file = strdup(file);
+	conf_err->line = line;
+	LIST_ADDQ(&curpx->conf.errors, &conf_err->list);
 
   out:
 	return ret;
 
 }
 
+/* Parses the "errorfiles" proxy keyword */
+static int proxy_parse_errorfiles(char **args, int section, struct proxy *curpx,
+				  struct proxy *defpx, const char *file, int line,
+				  char **err)
+{
+	struct conf_errors *conf_err = NULL;
+	char *name = NULL;
+	int rc, ret = 0;
+
+	if (warnifnotcap(curpx, PR_CAP_FE | PR_CAP_BE, file, line, args[0], NULL)) {
+		ret = 1;
+		goto out;
+	}
+
+	if (!*(args[1])) {
+		memprintf(err, "%s : expects <name> as argument.", args[0]);
+		ret = -1;
+		goto out;
+	}
+
+	name = strdup(args[1]);
+	conf_err = calloc(1, sizeof(*conf_err));
+	if (!name || !conf_err) {
+		memprintf(err, "%s : out of memory.", args[0]);
+		ret = -1;
+		goto error;
+	}
+	conf_err->type = 0;
+
+	conf_err->info.errorfiles.name = name;
+	if (!*(args[2])) {
+		for (rc = 0; rc < HTTP_ERR_SIZE; rc++)
+			conf_err->info.errorfiles.status[rc] = 1;
+	}
+	else {
+		int cur_arg, status;
+		for (cur_arg = 2; *(args[cur_arg]); cur_arg++) {
+			status = atol(args[cur_arg]);
+
+			for (rc = 0; rc < HTTP_ERR_SIZE; rc++) {
+				if (http_err_codes[rc] == status) {
+					conf_err->info.errorfiles.status[rc] = 2;
+					break;
+				}
+			}
+			if (rc >= HTTP_ERR_SIZE) {
+				memprintf(err, "%s : status code '%d' not handled.", args[0], status);
+				ret = -1;
+				goto out;
+			}
+		}
+	}
+	conf_err->file = strdup(file);
+	conf_err->line = line;
+	LIST_ADDQ(&curpx->conf.errors, &conf_err->list);
+  out:
+	return ret;
+
+  error:
+	free(name);
+	free(conf_err);
+	goto out;
+}
+
+/* Check "errorfiles" proxy keyword */
+static int proxy_check_errors(struct proxy *px)
+{
+	struct conf_errors *conf_err, *conf_err_back;
+	struct http_errors *http_errs;
+	int rc, err = 0;
+
+	list_for_each_entry_safe(conf_err, conf_err_back, &px->conf.errors, list) {
+		if (conf_err->type == 1) {
+			/* errorfile */
+			rc = http_get_status_idx(conf_err->info.errorfile.status);
+			px->errmsg[rc] = conf_err->info.errorfile.msg;
+		}
+		else {
+			/* errorfiles */
+			list_for_each_entry(http_errs, &http_errors_list, list) {
+				if (strcmp(http_errs->id, conf_err->info.errorfiles.name) == 0)
+					break;
+			}
+
+			/* unknown http-errors section */
+			if (&http_errs->list == &http_errors_list) {
+				ha_alert("config : proxy '%s': unknown http-errors section '%s' (at %s:%d).\n",
+					 px->id, conf_err->info.errorfiles.name, conf_err->file, conf_err->line);
+				err |= ERR_ALERT | ERR_FATAL;
+				free(conf_err->info.errorfiles.name);
+				goto next;
+			}
+
+			free(conf_err->info.errorfiles.name);
+			for (rc = 0; rc < HTTP_ERR_SIZE; rc++) {
+				if (conf_err->info.errorfiles.status[rc] > 0) {
+					if (http_errs->errmsg[rc])
+						px->errmsg[rc] = http_errs->errmsg[rc];
+					else if (conf_err->info.errorfiles.status[rc] == 2)
+						ha_warning("config: proxy '%s' : status '%d' not declared in"
+							   " http-errors section '%s' (at %s:%d).\n",
+							   px->id, http_err_codes[rc], http_errs->id,
+							   conf_err->file, conf_err->line);
+				}
+			}
+		}
+	  next:
+		LIST_DEL(&conf_err->list);
+		free(conf_err->file);
+		free(conf_err);
+	}
+
+  out:
+	return err;
+}
+
+int proxy_dup_default_conf_errors(struct proxy *curpx, struct proxy *defpx, char **errmsg)
+{
+	struct conf_errors *conf_err, *new_conf_err = NULL;
+	int ret = 0;
+
+	list_for_each_entry(conf_err, &defpx->conf.errors, list) {
+		new_conf_err = calloc(1, sizeof(*new_conf_err));
+		if (!new_conf_err) {
+			memprintf(errmsg, "unable to duplicate default errors (out of memory).");
+			goto out;
+		}
+		new_conf_err->type = conf_err->type;
+		if (conf_err->type == 1) {
+			new_conf_err->info.errorfile.status = conf_err->info.errorfile.status;
+			new_conf_err->info.errorfile.msg    = conf_err->info.errorfile.msg;
+		}
+		else {
+			new_conf_err->info.errorfiles.name = strdup(conf_err->info.errorfiles.name);
+			if (!new_conf_err->info.errorfiles.name) {
+				memprintf(errmsg, "unable to duplicate default errors (out of memory).");
+				goto out;
+			}
+			memcpy(&new_conf_err->info.errorfiles.status, &conf_err->info.errorfiles.status,
+			       sizeof(conf_err->info.errorfiles.status));
+		}
+		new_conf_err->file = strdup(conf_err->file);
+		new_conf_err->line = conf_err->line;
+		LIST_ADDQ(&curpx->conf.errors, &new_conf_err->list);
+		new_conf_err = NULL;
+	}
+	ret = 1;
+
+  out:
+	free(new_conf_err);
+	return ret;
+}
+
+void proxy_release_conf_errors(struct proxy *px)
+{
+	struct conf_errors *conf_err, *conf_err_back;
+
+	list_for_each_entry_safe(conf_err, conf_err_back, &px->conf.errors, list) {
+		if (conf_err->type == 0)
+			free(conf_err->info.errorfiles.name);
+		LIST_DEL(&conf_err->list);
+		free(conf_err->file);
+		free(conf_err);
+	}
+}
+
 /*
  * Parse an <http-errors> section.
  * Returns the error code, 0 if OK, or any combination of :
@@ -1218,10 +1429,12 @@ static struct cfg_kw_list cfg_kws = {ILH, {
         { CFG_LISTEN, "errorloc302",  proxy_parse_errorloc },
         { CFG_LISTEN, "errorloc303",  proxy_parse_errorloc },
         { CFG_LISTEN, "errorfile",    proxy_parse_errorfile },
+        { CFG_LISTEN, "errorfiles",   proxy_parse_errorfiles },
         { 0, NULL, NULL },
 }};
 
 INITCALL1(STG_REGISTER, cfg_register_keywords, &cfg_kws);
+REGISTER_POST_PROXY_CHECK(proxy_check_errors);
 
 REGISTER_CONFIG_SECTION("http-errors", cfg_parse_http_errors, NULL);
 

src/proxy.c

@@ -873,6 +873,7 @@ void init_new_proxy(struct proxy *p)
 	LIST_INIT(&p->format_unique_id);
 	LIST_INIT(&p->conf.bind);
 	LIST_INIT(&p->conf.listeners);
+	LIST_INIT(&p->conf.errors);
 	LIST_INIT(&p->conf.args.list);
 	LIST_INIT(&p->tcpcheck_rules);
 	LIST_INIT(&p->filter_configs);