admin: Improve handling of background jobs.

New commands BGCANCEL (cancel an outstanding job) and JOBS (list
outstanding jobs).

diff --git a/doc/tripe-admin.5.in b/doc/tripe-admin.5.in
index 3ea15b117401f848c27bddc7529e2d9973633fe1..9fd8a1d7f308ce20f96b6f6782728d1fce0dd152 100644 (file)
--- a/doc/tripe-admin.5.in
+++ b/doc/tripe-admin.5.in
@@ -257,6 +257,10 @@ Emits an
 line reporting the IP address and port number stored for
 .IR peer .
 .SP
+.BI "BGCANCEL " tag
+Cancels the background job with the named
+.IR tag .
+.SP
 .BI "CHECKCHAL " challenge
 Verifies a challenge as being one earlier issued by
 .B GETCHAL
@@ -311,6 +315,11 @@ packets which are to be encrypted and sent to
 Used by configuration scripts so that they can set up routing tables
 appropriately after adding new peers.
 .SP
+.B "JOBS"
+Emits an
+.B INFO
+line giving the tag for each outstanding background job.
+.SP
 .BI "KILL " peer
 Causes the server to forget all about
 .IR peer .
@@ -646,6 +655,11 @@ The DNS name
 .I hostname
 took too long to resolve.
 .SP
+.BI "tag-exists " tag
+(For long-running commands.)  The named
+.I tag
+is already the tag of an outstanding job.
+.SP
 .BI "unknown-command " token
 The command
 .B token
@@ -669,6 +683,14 @@ The service name
 .I service
 couldn't be found in 
 .BR /etc/services .
+.TP
+.BI "unknown-tag " tag
+(For
+.BR BGCANCEL .)
+The given
+.I tag
+is not the tag for any outstanding background job.  It may have just
+finished.
 .SH "NOTIFICATIONS"
 .\"* 30 Notification broadcasts (NOTE codes)
 The following notifications are sent to clients who request them.

diff --git a/server/admin.c b/server/admin.c
index 1660106c42b27e370b499f445409569f272b04c1..927f3ca4fa5085772bc55696ea78b4f4a80bf557 100644 (file)
--- a/server/admin.c
+++ b/server/admin.c
@@ -620,6 +620,25 @@ static peer *a_findpeer(admin *a, const char *pn)
 #define BGTAG(bg)                                                      \
   (((admin_bgop *)(bg))->tag ? ((admin_bgop *)(bg))->tag : "<foreground>")
 
+/* --- @a_bgfind@ --- *
+ *
+ * Arguments:  @admin *a@ = a client block
+ *             @const char *tag@ = the requested tag
+ *
+ * Returns:    The requested background job, or null.
+ */
+
+static admin_bgop *a_bgfind(admin *a, const char *tag)
+{
+  admin_bgop *bg;
+
+  for (bg = a->bg; bg; bg = bg->next) {
+    if (bg->tag && strcmp(tag, bg->tag) == 0)
+      return (bg);
+  }
+  return (0);
+}
+
 /* --- @a_bgrelease@ --- *
  *
  * Arguments:  @admin_bgop *bg@ = backgrounded operation
@@ -681,16 +700,21 @@ static void a_bgfail(admin_bgop *bg, const char *fmt, ...)
  *             @const char *tag@ = background tag, or null for foreground
  *             @void (*cancel)(admin_bgop *)@ = cancel function
  *
- * Returns:    ---
+ * Returns:    Zero for success, nonzero on failure.
  *
  * Use:                Links a background job into the list.
  */
 
-static void a_bgadd(admin *a, admin_bgop *bg, const char *tag,
-                   void (*cancel)(admin_bgop *))
+static int a_bgadd(admin *a, admin_bgop *bg, const char *tag,
+                  void (*cancel)(admin_bgop *))
 {
-  if (tag)
+  if (tag) {
+    if (a_bgfind(a, tag)) {
+      a_fail(a, "tag-exists", "%s", tag, A_END);
+      return (-1);
+    }
     bg->tag = xstrdup(tag);
+  }
   else {
     bg->tag = 0;
     selbuf_disable(&a->b);
@@ -703,6 +727,7 @@ static void a_bgadd(admin *a, admin_bgop *bg, const char *tag,
   a->bg = bg;
   T( trace(T_ADMIN, "admin: add bgop %s", BGTAG(bg)); )
   if (tag) a_write(a, "DETACH", tag, A_END);
+  return (0);
 }
 
 /*----- Name resolution operations ----------------------------------------*/
@@ -834,7 +859,8 @@ static void a_resolve(admin *a, admin_resop *r, const char *tag,
    * answer straight away.
    */
 
-  a_bgadd(a, &r->bg, tag, a_rescancel);
+  if (a_bgadd(a, &r->bg, tag, a_rescancel))
+    goto fail;
   T( trace(T_ADMIN, "admin: %u, resop %s, hostname `%s'",
           a->seq, BGTAG(r), r->addr); )
 
@@ -1086,7 +1112,8 @@ static void a_ping(admin *a, unsigned ac, char *av[],
     return;
   pg = xmalloc(sizeof(*pg));
   gettimeofday(&pg->pingtime, 0);
-  a_bgadd(a, &pg->bg, tag, a_pingcancel);
+  if (a_bgadd(a, &pg->bg, tag, a_pingcancel))
+    goto fail;
   T( trace(T_ADMIN, "admin: ping op %s: %s to %s",
           BGTAG(pg), cmd, p_name(p)); )
   if (p_pingsend(p, &pg->ping, msg, t, a_pong, pg)) {
@@ -1098,6 +1125,7 @@ static void a_ping(admin *a, unsigned ac, char *av[],
 bad_syntax:
   a_fail(a, "bad-syntax", "%s", cmd, "[OPTIONS] PEER", cmd, A_END);
 fail:
+  if (pg) xfree(pg);
   return;
 }
 
@@ -1225,6 +1253,30 @@ static void acmd_daemon(admin *a, unsigned ac, char *av[])
   }
 }
 
+static void acmd_jobs(admin *a, unsigned ac, char *av[])
+{
+  admin_bgop *bg;
+
+  for (bg = a->bg; bg; bg = bg->next) {
+    assert(bg->tag);
+    a_info(a, "%s", bg->tag, A_END);
+  }
+  a_ok(a);
+}
+
+static void acmd_bgcancel(admin *a, unsigned ac, char *av[])
+{
+  admin_bgop *bg;
+
+  if ((bg = a_bgfind(a, av[0])) == 0)
+    a_fail(a, "unknown-tag", "%s", av[0], A_END);
+  else {
+    bg->cancel(bg);
+    a_bgrelease(bg);
+    a_ok(a);
+  }
+}
+
 static void acmd_list(admin *a, unsigned ac, char *av[])
 {
   peer *p;
@@ -1414,6 +1466,7 @@ static void acmd_help(admin */*a*/, unsigned /*ac*/, char */*av*/[]);
 static const acmd acmdtab[] = {
   { "add",     "[OPTIONS] PEER ADDR ...", 2,   0xffff, acmd_add },
   { "addr",    "PEER",                 1,      1,      acmd_addr },
+  { "bgcancel",        "TAG",                  1,      1,      acmd_bgcancel },
   { "checkchal", "CHAL",               1,      1,      acmd_checkchal },
   { "daemon",  0,                      0,      0,      acmd_daemon },
   { "eping",   "[OPTIONS] PEER",       1,      0xffff, acmd_eping },
@@ -1422,6 +1475,7 @@ static const acmd acmdtab[] = {
   { "greet",   "PEER CHAL",            2,      2,      acmd_greet },
   { "help",    0,                      0,      0,      acmd_help },
   { "ifname",  "PEER",                 1,      1,      acmd_ifname },
+  { "jobs",    0,                      0,      0,      acmd_jobs },
   { "kill",    "PEER",                 1,      1,      acmd_kill },
   { "list",    0,                      0,      0,      acmd_list },
   { "notify",  "MESSAGE ...",          1,      0xffff, acmd_notify },