[MINOR] config: support resetting options do default values

A new keyword prefix "default" has been introduced in order to
reset some options to their default values. This can be needed
for instance when an option is forced disabled or enabled in a
defaults section and when later sections want to use automatic
settings regardless of what was specified there. Right now it
is only supported by options, just like the "no" prefix.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 8a2cc1cbd27c964e7e7b0dbb7e268bd2b582ae01..94d7861bb29cc0409717023e15d2d1f6c292bc10 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -637,9 +637,11 @@ The following list of keywords is supported. Most of them may only be used in a
 limited set of section types. Some of them are marked as "deprecated" because
 they are inherited from an old syntax which may be confusing or functionally
 limited, and there are new recommended keywords to replace them. Keywords
-listed with [no] can be optionally inverted using the "no" prefix, ex. "no
+listed with [no] can be optionally inverted using the "no" prefix, eg. "no
 option contstats". This makes sense when the option has been enabled by default
-and must be disabled for a specific instance.
+and must be disabled for a specific instance. Such options may also be prefixed
+with "default" in order to restore default settings regardless of what has been
+specified in a previous "defaults" section.
 
 
 keyword                 defaults   frontend   listen    backend

diff --git a/src/cfgparse.c b/src/cfgparse.c
index 2e079c71da901ed99e681a3be7a119304a8b41ab..af9af07584ee156e8dd5b968f9057092dce51308 100644 (file)
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -80,6 +80,13 @@ const char sslv3_client_hello_pkt[] = {
        "\x00"                /* Compression Type    : 0x00 = NULL compression   */
 };
 
+/* various keyword modifiers */
+enum kw_mod {
+       KWM_STD = 0,  /* normal */
+       KWM_NO,       /* "no" prefixed before the keyword */
+       KWM_DEF,      /* "default" prefixed before the keyword */
+};
+
 /* some of the most common options which are also the easiest to handle */
 struct cfg_opt {
        const char *name;
@@ -371,7 +378,7 @@ int warnif_misplaced_reqadd(struct proxy *proxy, const char *file, int line, cha
 /*
  * parse a line in a <global> section. Returns 0 if OK, -1 if error.
  */
-int cfg_parse_global(const char *file, int linenum, char **args, int inv)
+int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 {
 
        if (!strcmp(args[0], "global")) {  /* new section */
@@ -683,7 +690,7 @@ static void init_default_instance()
  * Parse a line in a <listen>, <frontend>, <backend> or <ruleset> section.
  * Returns 0 if OK, -1 if error.
  */
-int cfg_parse_listen(const char *file, int linenum, char **args, int inv)
+int cfg_parse_listen(const char *file, int linenum, char **args, int kwm)
 {
        static struct proxy *curproxy = NULL;
        struct server *newsrv = NULL;
@@ -1596,12 +1603,18 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int inv)
                                if (warnifnotcap(curproxy, cfg_opts[optnum].cap, file, linenum, args[1], NULL))
                                        return 0;
 
-                               if (!inv) {
-                                       curproxy->no_options &= ~cfg_opts[optnum].val;
-                                       curproxy->options    |=  cfg_opts[optnum].val;
-                               } else {
-                                       curproxy->options    &= ~cfg_opts[optnum].val;
-                                       curproxy->no_options |=  cfg_opts[optnum].val;
+                               curproxy->no_options &= ~cfg_opts[optnum].val;
+                               curproxy->options    &= ~cfg_opts[optnum].val;
+
+                               switch (kwm) {
+                               case KWM_STD:
+                                       curproxy->options |= cfg_opts[optnum].val;
+                                       break;
+                               case KWM_NO:
+                                       curproxy->no_options |= cfg_opts[optnum].val;
+                                       break;
+                               case KWM_DEF: /* already cleared */
+                                       break;
                                }
 
                                return 0;
@@ -1613,19 +1626,25 @@ int cfg_parse_listen(const char *file, int linenum, char **args, int inv)
                                if (warnifnotcap(curproxy, cfg_opts2[optnum].cap, file, linenum, args[1], NULL))
                                        return 0;
 
-                               if (!inv) {
-                                       curproxy->no_options2 &= ~cfg_opts2[optnum].val;
-                                       curproxy->options2    |=  cfg_opts2[optnum].val;
-                               } else {
-                                       curproxy->options2    &= ~cfg_opts2[optnum].val;
-                                       curproxy->no_options2 |=  cfg_opts2[optnum].val;
+                               curproxy->no_options2 &= ~cfg_opts2[optnum].val;
+                               curproxy->options2    &= ~cfg_opts2[optnum].val;
+
+                               switch (kwm) {
+                               case KWM_STD:
+                                       curproxy->options2 |= cfg_opts2[optnum].val;
+                                       break;
+                               case KWM_NO:
+                                       curproxy->no_options2 |= cfg_opts2[optnum].val;
+                                       break;
+                               case KWM_DEF: /* already cleared */
+                                       break;
                                }
                                return 0;
                        }
                }
 
-               if (inv) {
-                       Alert("parsing [%s:%d]: negation is not supported for option '%s'.\n",
+               if (kwm != KWM_STD) {
+                       Alert("parsing [%s:%d]: negation/default is not supported for option '%s'.\n",
                                file, linenum, args[1]);
                        return -1;
                }
@@ -3182,7 +3201,7 @@ int readcfgfile(const char *file)
        init_default_instance();
 
        while (fgets(thisline, sizeof(thisline), f) != NULL) {
-               int arg, inv = 0 ;
+               int arg, kwm = KWM_STD;
                char *end;
                char *args[MAX_LINE_ARGS + 1];
                char *line = thisline;
@@ -3278,14 +3297,20 @@ int readcfgfile(const char *file)
                        args[arg] = line;
                }
 
+               /* check for keyword modifiers "no" and "default" */
                if (!strcmp(args[0], "no")) {
-                       inv = 1;
+                       kwm = KWM_NO;
+                       for (arg=0; *args[arg+1]; arg++)
+                               args[arg] = args[arg+1];                // shift args after inversion
+               }
+               else if (!strcmp(args[0], "default")) {
+                       kwm = KWM_DEF;
                        for (arg=0; *args[arg+1]; arg++)
                                args[arg] = args[arg+1];                // shift args after inversion
                }
 
-               if (inv && strcmp(args[0], "option")) {
-                       Alert("parsing [%s:%d]: negation currently supported only for options.\n", file, linenum);
+               if (kwm != KWM_STD && strcmp(args[0], "option") != 0) {
+                       Alert("parsing [%s:%d]: negation/default currently supported only for options.\n", file, linenum);
                        goto err;
                }
 
@@ -3307,11 +3332,11 @@ int readcfgfile(const char *file)
 
                switch (confsect) {
                case CFG_LISTEN:
-                       if (cfg_parse_listen(file, linenum, args, inv) < 0)
+                       if (cfg_parse_listen(file, linenum, args, kwm) < 0)
                                goto err;
                        break;
                case CFG_GLOBAL:
-                       if (cfg_parse_global(file, linenum, args, inv) < 0)
+                       if (cfg_parse_global(file, linenum, args, kwm) < 0)
                                goto err;
                        break;
                default: