MEDIUM: checks: provide environment variables to the external checks

The external command accepted 4 arguments, some with the value "NOT_USED" when
not applicable. In order to make the exernal command more generic, this patch
also provides the values in environment variables. This allows to provide more
information.

Currently, the supported environment variables are :

PATH, as previously provided.

HAPROXY_PROXY_NAME, the backend name
HAPROXY_PROXY_ID, the backend id
HAPROXY_PROXY_ADDR, the first bind address if available (or empty)
HAPROXY_PROXY_PORT, the first bind port if available (or empty)

HAPROXY_SERVER_NAME, the server name
HAPROXY_SERVER_ID, the server id
HAPROXY_SERVER_ADDR, the server address
HAPROXY_SERVER_PORT, the server port if available (or empty)
HAPROXY_SERVER_MAXCONN, the server max connections
HAPROXY_SERVER_CURCONN, the current number of connections on the server

diff --git a/src/checks.c b/src/checks.c
index bb8b719ebeb9091bdb1d94c4c35ca1fd5316c847..03ddb26c44b6e4d7051a8e065b1e820e71ba97ed 100644 (file)
--- a/src/checks.c
+++ b/src/checks.c
@@ -1568,6 +1568,52 @@ static int init_pid_list(void) {
        return 0;
 }
 
+#define EXTCHECK_ARG_MAX 5
+#define EXTCHECK_ENV_ROOM 16
+
+#define EXTCHECK_ADD_ENV(check, envname, value, idx) { if (external_check_add_env(check, envname, value, idx)) goto err; }
+
+/*
+ * helper function to allocate enough space for new environment variables used
+ * by external checks.
+ */
+static int external_check_add_env(struct check *check, const char *envname, const char *value, int *idx)
+{
+       int len, ret;
+
+       if (*idx % EXTCHECK_ENV_ROOM == 0) {
+               /* Allocate enough space to store new environment variables */
+               char **tmp = realloc(check->envp, (EXTCHECK_ENV_ROOM * ((*idx / EXTCHECK_ENV_ROOM) + 1) + 1) * sizeof(check->envp));
+               if (tmp == NULL) {
+                       Alert("Failed to allocate memory for new environment variables. Aborting\n");
+                       return 1;
+               } else {
+                       check->envp = tmp;
+               }
+       }
+       /* Instead of sending NOT_USED, sending an empty value is preferable */
+       if (strcmp(value, "NOT_USED") == 0) {
+               value = "";
+       }
+       len = strlen(envname) + strlen(value) + 1;
+       check->envp[*idx] = malloc(len + 1);
+       check->envp[*idx + 1] = NULL;
+       if (!check->envp[*idx]) {
+               Alert("Failed to allocate memory for the environment variable '%s'. Aborting.\n", envname);
+               return 1;
+       }
+       ret = snprintf(check->envp[*idx], len + 1, "%s=%s", envname, value);
+       if (ret < 0) {
+               Alert("Failed to store the environment variable '%s'. Reason : %s. Aborting.\n", envname, strerror(errno));
+               return 1;
+       }
+       else if (ret != len) {
+               Alert("Environment variable '%s' was truncated. Aborting.\n", envname);
+               return 1;
+       }
+       (*idx)++;
+       return 0;
+}
 
 static int prepare_external_check(struct check *check)
 {
@@ -1575,10 +1621,9 @@ static int prepare_external_check(struct check *check)
        struct proxy *px = s->proxy;
        struct listener *listener = NULL, *l;
        int i;
-       const char *err_fmt = "Starting [%s:%s] check: out of memory.\n";
+       int envidx = 0;
        const char *path = px->check_path ? px->check_path : DEF_CHECK_PATH;
-       char host[46];
-       char serv[6];
+       char buf[256];
 
        list_for_each_entry(l, &px->conf.listeners, by_fe)
                /* Use the first INET, INET6 or UNIX listener */
@@ -1590,18 +1635,9 @@ static int prepare_external_check(struct check *check)
                }
 
        check->curpid = NULL;
+       check->envp = NULL;
 
-       check->envp = calloc(2, sizeof(check->argv));
-       if (!check->envp)
-               goto err;
-       check->envp[0] = malloc(strlen("PATH=") + strlen(path) + 1);
-       if (!check->envp[0])
-               goto err;
-       strcpy(check->envp[0], "PATH=");
-       strcpy(check->envp[0] + strlen(check->envp[0]), path);
-       check->envp[1] = NULL;
-
-       check->argv = calloc(6, sizeof(check->argv));
+       check->argv = calloc(EXTCHECK_ARG_MAX + 1, sizeof(check->argv));
        if (!check->argv)
                goto err;
 
@@ -1613,10 +1649,10 @@ static int prepare_external_check(struct check *check)
        }
        else if (listener->addr.ss_family == AF_INET ||
            listener->addr.ss_family == AF_INET6) {
-               addr_to_str(&listener->addr, host, sizeof(host));
-               check->argv[1] = strdup(host);
-               port_to_str(&listener->addr, serv, sizeof(serv));
-               check->argv[2] = strdup(serv);
+               addr_to_str(&listener->addr, buf, sizeof(buf));
+               check->argv[1] = strdup(buf);
+               port_to_str(&listener->addr, buf, sizeof(buf));
+               check->argv[2] = strdup(buf);
        }
        else if (listener->addr.ss_family == AF_UNIX) {
                const struct sockaddr_un *un;
@@ -1629,19 +1665,34 @@ static int prepare_external_check(struct check *check)
                goto err;
        }
 
-       addr_to_str(&s->addr, host, sizeof(host));
-       check->argv[3] = strdup(host);
-       port_to_str(&s->addr, serv, sizeof(serv));
-       check->argv[4] = strdup(serv);
+       addr_to_str(&s->addr, buf, sizeof(buf));
+       check->argv[3] = strdup(buf);
+       port_to_str(&s->addr, buf, sizeof(buf));
+       check->argv[4] = strdup(buf);
 
        for (i = 0; i < 5; i++)
                if (!check->argv[i])
                        goto err;
 
+       EXTCHECK_ADD_ENV(check, "PATH", path, &envidx);
+       /* Add proxy environment variables */
+       EXTCHECK_ADD_ENV(check, "HAPROXY_PROXY_NAME", px->id, &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_PROXY_ID", ultoa_r(px->uuid, buf, sizeof(buf)), &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_PROXY_ADDR", check->argv[1], &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_PROXY_PORT", check->argv[2], &envidx);
+       /* Add server environment variables */
+       EXTCHECK_ADD_ENV(check, "HAPROXY_SERVER_NAME", s->id, &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_SERVER_ID", ultoa_r(s->puid, buf, sizeof(buf)), &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_SERVER_ADDR", check->argv[3], &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_SERVER_PORT", check->argv[4], &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_SERVER_MAXCONN", ultoa_r(s->maxconn, buf, sizeof(buf)), &envidx);
+       EXTCHECK_ADD_ENV(check, "HAPROXY_SERVER_CURCONN", ultoa_r(s->cur_sess, buf, sizeof(buf)), &envidx);
+
        return 1;
 err:
        if (check->envp) {
-               free(check->envp[1]);
+               for (i = 0; i < envidx; i++)
+                       free(check->envp[i]);
                free(check->envp);
                check->envp = NULL;
        }
@@ -1652,7 +1703,6 @@ err:
                free(check->argv);
                check->argv = NULL;
        }
-       Alert(err_fmt, px->id, s->id);
        return 0;
 }