admin: Service ownership infrastructure and commands.

  * Implement a table of named and versioned services.

  * Allow clients to claim and release services, and find out about
    claimed services.

  * Notify clients when services are claimed and released.

  * Notify a service provider when another client provides a later
    version.

diff --git a/server/admin.c b/server/admin.c
index 6ff88159dcb90e5c228ac294b33568dc8caab3b4..eb48039887679aa529393b945dd4e9c2855b9d8a 100644 (file)
--- a/server/admin.c
+++ b/server/admin.c
@@ -65,6 +65,7 @@ static admin *admins;
 static admin *a_dead;
 static sel_file sock;
 static const char *sockname;
+static sym_table a_svcs;
 static unsigned flags = 0;
 static admin *a_stdin = 0;
 static sig s_term, s_int, s_hup;
@@ -731,6 +732,68 @@ static int a_bgadd(admin *a, admin_bgop *bg, const char *tag,
   return (0);
 }
 
+/*----- Services infrastructure -------------------------------------------*/
+
+/* --- @a_svcfind@ --- *
+ *
+ * Arguments:  @admin *a@ = the requesting client
+ *             @const char *name@ = service name wanted
+ *
+ * Returns:    The service requested, or null.
+ *
+ * Use:                Finds a service; reports an error if the service couldn't be
+ *             found.
+ */
+
+static admin_service *a_svcfind(admin *a, const char *name)
+{
+  admin_service *svc;
+
+  if ((svc = sym_find(&a_svcs, name, -1, 0, 0)) == 0) {
+    a_fail(a, "unknown-service", "%s", name, A_END);
+    return (0);
+  }
+  return (svc);
+}
+
+/* --- @a_svcunlink@ --- *
+ *
+ * Arguments:  @admin_service *svc@ = pointer to service structure
+ *
+ * Returns:    ---
+ *
+ * Use:                Unlinks the service from its provider, without issuing a
+ *             message or freeing the structure.  The version string is
+ *             freed, however.
+ */
+
+static void a_svcunlink(admin_service *svc)
+{
+  if (svc->next)
+    svc->next->prev = svc->prev;
+  if (svc->prev)
+    svc->prev->next = svc->next;
+  else
+    svc->prov->svcs = svc->next;
+  xfree(svc->version);
+}
+
+/* --- @a_svcrelease@ --- *
+ *
+ * Arguments:  @admin_service *svc@ = pointer to service structure
+ *
+ * Returns:    ---
+ *
+ * Use:                Releases a service and frees its structure.
+ */
+
+static void a_svcrelease(admin_service *svc)
+{
+  a_notify("SVCRELEASE", "%s", SYM_NAME(svc), A_END);
+  a_svcunlink(svc);
+  sym_remove(&a_svcs, svc);
+}
+
 /*----- Name resolution operations ----------------------------------------*/
 
 /* --- @a_resolved@ --- *
@@ -843,7 +906,7 @@ static void a_resolve(admin *a, admin_resop *r, const char *tag,
   if (*p) {
     struct servent *s = getservbyname(av[i + 1], "udp");
     if (!s) {
-      a_fail(a, "unknown-port", "%s", av[i + 1], A_END);
+      a_fail(a, "unknown-service", "%s", av[i + 1], A_END);
       goto fail;
     }
     pt = ntohs(s->s_port);
@@ -1135,6 +1198,86 @@ static void acmd_ping(admin *a, unsigned ac, char *av[])
 static void acmd_eping(admin *a, unsigned ac, char *av[])
   { a_ping(a, ac, av, "eping", MISC_EPING); }
 
+/*----- Service commands --------------------------------------------------*/
+
+static void acmd_svcclaim(admin *a, unsigned ac, char *av[])
+{
+  admin_service *svc;
+  unsigned f;
+
+  svc = sym_find(&a_svcs, av[0], -1, sizeof(*svc), &f);
+  if (f) {
+    if (versioncmp(av[1], svc->version) <= 0) {
+      a_fail(a,
+            "service-exists",
+            "%s", SYM_NAME(svc),
+            "%s", svc->version,
+            A_END);
+      return;
+    }
+    a_write(svc->prov, "SVCCLAIM", 0, "%s", av[0], "%s", av[1], A_END);
+    a_svcunlink(svc);
+  }
+  svc->prov = a;
+  svc->version = xstrdup(av[1]);
+  svc->next = a->svcs;
+  svc->prev = 0;
+  if (a->svcs) a->svcs->prev = svc;
+  a->svcs = svc;
+  a_notify("SVCCLAIM", "%s", SYM_NAME(svc), "%s", svc->version, A_END);
+  a_ok(a);
+}
+
+static void acmd_svcrelease(admin *a, unsigned ac, char *av[])
+{
+  admin_service *svc;
+
+  if ((svc = a_svcfind(a, av[0])) == 0)
+    return;
+  if (svc->prov != a) {
+    a_fail(a, "not-service-provider", "%s", SYM_NAME(svc), A_END);
+    return;
+  }
+  a_svcrelease(svc);
+  a_ok(a);
+}
+
+static void acmd_svcensure(admin *a, unsigned ac, char *av[])
+{
+  admin_service *svc;
+
+  if ((svc = a_svcfind(a, av[0])) == 0)
+    return;
+  if (av[1] && versioncmp(svc->version, av[1]) < 0) {
+    a_fail(a, "service-too-old",
+          "%s", SYM_NAME(svc),
+          "%s", svc->version,
+          A_END);
+    return;
+  }
+  a_ok(a);
+}
+
+static void acmd_svcquery(admin *a, unsigned ac, char *av[])
+{
+  admin_service *svc;
+
+  if ((svc = a_svcfind(a, av[0])) != 0) {
+    a_info(a, "name=%s", SYM_NAME(svc), "version=%s", svc->version, A_END);
+    a_ok(a);
+  }
+}
+
+static void acmd_svclist(admin *a, unsigned ac, char *av[])
+{
+  admin_service *svc;
+  sym_iter i;
+
+  for (sym_mkiter(&i, &a_svcs); (svc = sym_next(&i)) != 0; )
+    a_info(a, "%s", SYM_NAME(svc), "%s", svc->version, A_END);
+  a_ok(a);
+}
+
 /*----- Administration commands -------------------------------------------*/
 
 /* --- Miscellaneous commands --- */
@@ -1475,6 +1618,11 @@ static const acmd acmdtab[] = {
   { "reload",  0,                      0,      0,      acmd_reload },
   { "servinfo",        0,                      0,      0,      acmd_servinfo },
   { "setifname", "PEER NEW-NAME",      2,      2,      acmd_setifname },
+  { "svcclaim",        "SERVICE VERSION",      2,      2,      acmd_svcclaim },
+  { "svcensure", "SERVICE [VERSION]",  1,      2,      acmd_svcensure },
+  { "svclist", 0,                      0,      0,      acmd_svclist },
+  { "svcquery",        "SERVICE",              1,      1,      acmd_svcquery },
+  { "svcrelease", "SERVICE",           1,      1,      acmd_svcrelease },
   { "stats",   "PEER",                 1,      1,      acmd_stats },
 #ifndef NTRACE
   { "trace",   "[OPTIONS]",            0,      1,      acmd_trace },
@@ -1513,6 +1661,7 @@ static void a_destroypending(void)
 {
   admin *a, *aa;
   admin_bgop *bg, *bbg;
+  admin_service *svc, *ssvc;
 
   /* --- Destroy connections marked as pending --- */
 
@@ -1534,6 +1683,13 @@ static void a_destroypending(void)
       xfree(bg);
     }
 
+    /* --- Release services I hold --- */
+
+    for (svc = a->svcs; svc; svc = ssvc) {
+      ssvc = svc->next;
+      a_svcrelease(svc);
+    }
+
     /* --- Close file descriptors and selectory --- */
 
     selbuf_destroy(&a->b);
@@ -1659,6 +1815,7 @@ void a_create(int fd_in, int fd_out, unsigned f)
   T( trace(T_ADMIN, "admin: accepted connection %u", a->seq); )
   a->bg = 0;
   a->ref = 0;
+  a->svcs = 0;
   a->f = f;
   if (fd_in == STDIN_FILENO) a_stdin = a;
   fdflags(fd_in, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
@@ -1743,6 +1900,10 @@ void a_init(const char *name)
   struct sigaction sa;
   size_t sz;
 
+  /* --- Create services table --- */
+
+  sym_create(&a_svcs);
+
   /* --- Set up the socket address --- */
 
   sz = strlen(name) + 1;

diff --git a/server/tripe.h b/server/tripe.h
index e917ddb0b241afa306f5d328382e9536b8dfa148..1cb2d4078687b59ecd2c746a32b0740837139f5b 100644 (file)
--- a/server/tripe.h
+++ b/server/tripe.h
@@ -391,7 +391,14 @@ typedef struct admin_pingop {
   admin_bgop bg;                       /* Background operation header */
   ping ping;                           /* Ping pending response */
   struct timeval pingtime;             /* Time last ping was sent */
-} admin_pingop;  
+} admin_pingop;
+
+typedef struct admin_service {
+  sym_base _b;                         /* Hash table base structure */
+  char *version;                       /* The provided version */
+  struct admin *prov;                  /* Which client provides me */
+  struct admin_service *next, *prev;   /* Client's list of services */
+} admin_service;
 
 typedef struct admin {
   struct admin *next, *prev;           /* Links to next and previous */
@@ -403,6 +410,7 @@ typedef struct admin {
   oqueue out;                          /* Output buffer list */
   oqueue delay;                                /* Delayed output buffer list */
   admin_bgop *bg;                      /* Backgrounded operations */
+  admin_service *svcs;                 /* Which services I provide */
   selbuf b;                            /* Line buffer for commands */
   sel_file w;                          /* Selector for write buffering */
 } admin;