wgtpkg-install: Improve port allocation

The algorithm that allocates ports is improved
by:

 - allocating ports in the range 31000...32759
 - avoiding systematic rescan

Change-Id: I72771cf3f361f4977edc7b59c75921e71f5b470b
Signed-off-by: José Bollo <jose.bollo@iot.bzh>

diff --git a/src/wgtpkg-install.c b/src/wgtpkg-install.c
index 31ef7c4..c5c41ea 100644 (file)
--- a/src/wgtpkg-install.c
+++ b/src/wgtpkg-install.c
@@ -55,6 +55,18 @@ static const char* exec_type_strings[] = {
 static const char key_afm_prefix[] = "X-AFM-";
 static const char key_http_port[] = "http-port";
 
+#define HTTP_PORT_MIN                  31000
+#define HTTP_PORT_MAX                  32759
+#define HTTP_PORT_IS_VALID(port)       (HTTP_PORT_MIN <= (port) && (port) <= HTTP_PORT_MAX)
+#define HTTP_PORT_COUNT                        (HTTP_PORT_MAX - HTTP_PORT_MIN + 1)
+#define HTTP_PORT_ACNT                 ((HTTP_PORT_COUNT + 31) >> 5)
+#define HTTP_PORT_ASFT(port)           (((port) - HTTP_PORT_MIN) & 31)
+#define HTTP_PORT_AIDX(port)           (((port) - HTTP_PORT_MIN) >> 5)
+#define HTTP_PORT_TEST(array,port)     ((((array)[HTTP_PORT_AIDX(port)]) >> HTTP_PORT_ASFT(port)) & 1)
+#define HTTP_PORT_SET(array,port)      (((array)[HTTP_PORT_AIDX(port)]) |= (((uint32_t)1) << HTTP_PORT_ASFT(port)))
+
+static uint32_t *port_bits = NULL;
+
 /*
  * normalize unit files: remove comments, remove heading blanks,
  * make single lines
@@ -115,8 +127,8 @@ static int get_port_cb(void *closure, const char *name, const char *path, int is
                        if (*iter == '=') {
                                while(*++iter == ' ');
                                p = atoi(iter);
-                               if (p >= 0 && p < 32768)
-                                       ((uint32_t*)closure)[p >> 5] |= (uint32_t)1 << (p & 31);
+                               if (HTTP_PORT_IS_VALID(p))
+                                       HTTP_PORT_SET((uint32_t*)closure, p);
                        }
                }
                iter = strstr(iter, key_afm_prefix);
@@ -125,29 +137,55 @@ static int get_port_cb(void *closure, const char *name, const char *path, int is
        return 0;
 }
 
-static int get_port()
+static int update_portbits(uint32_t *portbits)
 {
        int rc;
-       uint32_t ports[1024]; /* 1024 * 32 = 32768 */
-
-       memset(ports, 0, sizeof ports);
-       rc = systemd_unit_list(0, get_port_cb, &ports);
-       if (rc >= 0) {
-               rc = systemd_unit_list(1, get_port_cb, ports);
-               if (rc >= 0) {
-                       for (rc = 1024 ; rc < 32768 && !~ports[rc >> 5] ; rc += 32);
-                       if (rc == 32768) {
-                               ERROR("Can't compute a valid port");
-                               errno = EADDRNOTAVAIL;
-                               rc = -1;
-                       } else {
-                               while (1 & (ports[rc >> 5] >> (rc & 31))) rc++;
-                       }
-               }
-       }
+
+       memset(portbits, 0, HTTP_PORT_ACNT * sizeof(uint32_t));
+       rc = systemd_unit_list(0, get_port_cb, portbits);
+       if (rc >= 0)
+               rc = systemd_unit_list(1, get_port_cb, portbits);
+       if (rc < 0)
+               ERROR("troubles while updating ports");
        return rc;
 }
 
+static int first_free_port(uint32_t *portbits)
+{
+       int port;
+
+       port = HTTP_PORT_MIN;
+       while (port <= HTTP_PORT_MAX && !~portbits[HTTP_PORT_AIDX(port)])
+               port += 32;
+       while (port <= HTTP_PORT_MAX && HTTP_PORT_TEST(portbits, port))
+               port++;
+       if (port > HTTP_PORT_MAX) {
+               ERROR("Can't compute a valid port");
+               errno = EADDRNOTAVAIL;
+               port = -1;
+       }
+       return port;
+}
+
+static int get_port()
+{
+       int port;
+
+       /* ensure existing port bitmap */
+       if (port_bits == NULL) {
+               port_bits = malloc(HTTP_PORT_ACNT * sizeof(uint32_t));
+               if (port_bits == NULL || update_portbits(port_bits) < 0)
+                       return -1;
+       }
+
+       /* allocates the port */
+       port = first_free_port(port_bits);
+       if (port >= 0)
+               HTTP_PORT_SET(port_bits, port);
+
+       return port;
+}
+
 static int check_defined(const void *data, const char *name)
 {
        if (data)