MINOR: haproxy: permit to register features during boot

The regtests are using the "feature()" predicate but this one can only
rely on build-time options. It would be nice if some runtime-specific
options could be detected at boot time so that regtests could more
flexibly adapt to what is supported (capabilities, splicing, etc).

Similarly, certain features that are currently enabled with USE_XXX
could also be automatically detected at build time using ifdefs and
would simplify the configuration, but then we'd lose the feature
report in the feature list which is convenient for regtests.

This patch makes sure that haproxy -vv shows the variable's contents
and not the macro's contents, and adds a new hap_register_feature()
to allow the code to register a new keyword.

diff --git a/include/haproxy/global.h b/include/haproxy/global.h
index e058d25e214871a2cda67a2349b6bbcf73d90232..6eb3ad738c351907dcecbbd9b55ef48716618bc5 100644 (file)
--- a/include/haproxy/global.h
+++ b/include/haproxy/global.h
@@ -25,7 +25,7 @@
 #include <haproxy/api-t.h>
 #include <haproxy/global-t.h>
 
-extern const char *build_features;
+extern char *build_features;
 extern struct global global;
 extern int  pid;                /* current process id */
 extern int  actconn;            /* # of active sessions */
@@ -60,6 +60,7 @@ void run_poll_loop(void);
 int tell_old_pids(int sig);
 int delete_oldpid(int pid);
 void hap_register_build_opts(const char *str, int must_free);
+void hap_register_feature(const char *name);
 int split_version(const char *version, unsigned int *value);
 int compare_current_version(const char *version);
 void display_version();

diff --git a/src/haproxy.c b/src/haproxy.c
index 383d1e47dcd80b49c6c63cefe2e2ad12bb639596..dc6bc856685367614a0a271a8be91b0365e18733 100644 (file)
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -159,9 +159,9 @@ DECLARE_INIT_STAGES;
 empty_t __read_mostly_align HA_SECTION("read_mostly") ALIGNED(64);
 
 #ifdef BUILD_FEATURES
-const char *build_features = BUILD_FEATURES;
+char *build_features = BUILD_FEATURES;
 #else
-const char *build_features = "";
+char *build_features = "";
 #endif
 
 /* list of config files */
@@ -333,6 +333,30 @@ void hap_register_build_opts(const char *str, int must_free)
        LIST_APPEND(&build_opts_list, &b->list);
 }
 
+/* used to make a new feature appear in the build_features list at boot time.
+ * The feature must be in the format "XXX" without the leading "+" which will
+ * be automatically appended.
+ */
+void hap_register_feature(const char *name)
+{
+       static int must_free = 0;
+       int new_len = strlen(build_features) + 2 + strlen(name);
+       char *new_features;
+
+       new_features = malloc(new_len + 1);
+       if (!new_features)
+               return;
+
+       strlcpy2(new_features, build_features, new_len);
+       snprintf(new_features, new_len + 1, "%s +%s", build_features, name);
+
+       if (must_free)
+               ha_free(&build_features);
+
+       build_features = new_features;
+       must_free = 1;
+}
+
 #define VERSION_MAX_ELTS  7
 
 /* This function splits an haproxy version string into an array of integers.
@@ -545,13 +569,11 @@ static void display_build_opts()
 #ifdef BUILD_DEBUG
               "\n  DEBUG   = " BUILD_DEBUG
 #endif
-#ifdef BUILD_FEATURES
-              "\n\nFeature list : " BUILD_FEATURES
-#endif
+              "\n\nFeature list : %s"
               "\n\nDefault settings :"
               "\n  bufsize = %d, maxrewrite = %d, maxpollevents = %d"
               "\n\n",
-              BUFSIZE, MAXREWRITE, MAX_POLL_EVENTS);
+              build_features, BUFSIZE, MAXREWRITE, MAX_POLL_EVENTS);
 
        list_for_each_entry(item, &build_opts_list, list) {
                puts(item->str);