]> git.ozlabs.org Git - ccan-lca-2011.git/blobdiff - ccan/oserver/oserver.c
lca2011: dump, re-exec with --restore on restart.
[ccan-lca-2011.git] / ccan / oserver / oserver.c
index 20edfcbc19a79c846d3e2f31d834eebccd64fced..d4266eda1ef5ead9329ecd5e4136e307a8a162d4 100644 (file)
@@ -1,7 +1,11 @@
 #include <ccan/oserver/oserver.h>
+#include <ccan/oserver/oserver_types.h>
+#include <ccan/oserver/oserver_cdump.h>
 #include <ccan/read_write_all/read_write_all.h>
 #include <ccan/opt/opt.h>
-#include <ccan/noerr/noerr.h>
+#include <ccan/tevent/tevent.h>
+#include <ccan/array_size/array_size.h>
+#include <ccan/grab_file/grab_file.h>
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <signal.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+static uint16_t state_flag_map[] = {
+       [SENDING_GREETING]              = TEVENT_FD_WRITE,
+       [RECEIVING_USER_QUESTION]       = TEVENT_FD_READ,
+       [SENDING_OTHER_QUESTION_PREFIX] = TEVENT_FD_WRITE,
+       [SENDING_OTHER_QUESTION]        = TEVENT_FD_WRITE,
+       [RECEIVING_OTHER_ANSWER]        = TEVENT_FD_READ,
+       [SENDING_ANSWER_PREFIX]         = TEVENT_FD_WRITE,
+       [SENDING_ANSWER]                = TEVENT_FD_WRITE,
+       [FINISHED]                      = 0
+};
+
+static ssize_t write_string(int fd, const char *str)
+{
+       return write(fd, str, strlen(str));
+}
+
+static ssize_t read_string(int fd, char **buf)
+{
+       ssize_t ret, len, maxlen;
+
+       len = strlen(*buf);
+       maxlen = talloc_array_length(*buf);
+
+       if (maxlen < len + 100) {
+               maxlen += 100;
+               *buf = talloc_realloc(NULL, *buf, char, maxlen);
+       }
+
+       ret = read(fd, *buf + len, maxlen - len - 1);
+       if (ret >= 0)
+               (*buf)[len + ret] = '\0';
+       return ret;
+}
+
+static bool input_finished(const char *str)
+{
+       return strchr(str, '\n');
+}
+
+/* Update state, and set our READ/WRITE flags appropriately. */
+static void set_state(struct client *c, enum state state)
+{
+       c->state = state;
+       tevent_fd_set_flags(c->fde, state_flag_map[state]);
+}
+
+/* Returns false on error, increments state on finishing string. */
+static bool send_string(struct client *c, const char *str)
+{
+       ssize_t len = write_string(c->fd, str + c->bytes_sent);
+       if (len < 0)
+               return false;
+       c->bytes_sent += len;
+       if (c->bytes_sent == strlen(str)) {
+               c->bytes_sent = 0;
+               set_state(c, c->state+1);
+       }
+       return true;
+}
+
+static bool get_subclient(struct client *me)
+{
+       unsigned int i;
 
-bool oserver_serve(int fd)
+       for (i = 0; i < ARRAY_SIZE(me->oserver->clients); i++) {
+               struct client *c = me->oserver->clients[i];
+               if (!c || c == me)
+                       continue;
+               if (c->oracle == -1 && input_finished(c->question)) {
+                       me->subclient = c->id;
+                       c->oracle = me->id;
+                       return true;
+               }
+       }
+       return false;
+}
+
+static bool get_oracle(struct client *me)
 {
-       char buf[1024];
        unsigned int i;
 
-       for (i = 0; i < sizeof(buf)-1; i++) {
-               if (read(fd, &buf[i], 1) != 1) {
-                       errno = EIO;
-                       return false;
+       for (i = 0; i < ARRAY_SIZE(me->oserver->clients); i++) {
+               struct client *c = me->oserver->clients[i];
+               if (!c || c == me)
+                       continue;
+               if (c->subclient == -1 && input_finished(c->question)) {
+                       me->oracle = c->id;
+                       c->subclient = me->id;
+                       return true;
+               }
+       }
+       return false;
+}
+
+static void wakeup(struct client *c)
+{
+       tevent_fd_set_flags(c->fde, state_flag_map[c->state]);
+}
+
+static void service_client(struct tevent_context *ev,
+                          struct tevent_fd *fde, uint16_t flags, void *_c)
+{
+       struct client *c = _c;
+       ssize_t len;
+
+       switch (c->state) {
+       case SENDING_GREETING:
+               if (!send_string(c, "Welcome.  Please ask your question.\n"))
+                       goto fail;
+               break;
+       case RECEIVING_USER_QUESTION:
+               len = read_string(c->fd, &c->question);
+               if (len <= 0)
+                       goto fail;
+               if (input_finished(c->question))
+                       set_state(c, SENDING_OTHER_QUESTION_PREFIX);
+               break;
+       case SENDING_OTHER_QUESTION_PREFIX:
+               if (c->subclient == -1)
+                       goto need_subclient;
+               if (!send_string(c, "While the Oracle ponders,"
+                                " please answer the following question:\n"))
+                       goto fail;
+               break;
+       case SENDING_OTHER_QUESTION:
+               if (c->subclient == -1)
+                       goto need_subclient;
+               if (!send_string(c,
+                                c->oserver->clients[c->subclient]->question))
+                       goto fail;
+               break;
+       case RECEIVING_OTHER_ANSWER:
+               if (c->subclient == -1)
+                       goto need_subclient;
+               len = read_string(c->fd,
+                                 &c->oserver->clients[c->subclient]->answer);
+               if (len <= 0)
+                       goto fail;
+               if (input_finished(c->oserver->clients[c->subclient]->answer)) {
+                       set_state(c, SENDING_ANSWER_PREFIX);
+                       wakeup(c->oserver->clients[c->subclient]);
+               }
+               break;
+       case SENDING_ANSWER_PREFIX:
+               if (!input_finished(c->answer))
+                       goto need_answer;
+               if (!send_string(c, "The Oracle spake thus:\n"))
+                       goto fail;
+               break;
+       case SENDING_ANSWER:
+               if (!send_string(c, c->answer))
+                       goto fail;
+               break;
+       default:
+               goto fail;
+       }
+
+       if (c->state != FINISHED)
+               return;
+fail:
+       talloc_free(c);
+       return;
+
+need_subclient:
+       if (!get_subclient(c)) {
+               /* We can't get one: go to sleep until someone find_oracle() */
+               tevent_fd_set_flags(c->fde, 0);
+       } else
+               /* In case they are waiting... */
+               wakeup(c->oserver->clients[c->subclient]);
+       return;
+
+need_answer:
+       /* If we don't have an oracle and find one, that's OK. */
+       if (c->oracle == -1 && get_oracle(c)) {
+               /* In case they are waiting... */
+               wakeup(c->oserver->clients[c->oracle]);
+               return;
+       }
+
+       /* Either our oracle is not finished, or we don't have one: sleep. */
+       tevent_fd_set_flags(c->fde, 0);
+}
+
+static int cleanup_client(struct client *client)
+{
+
+       /* We were an oracle? */
+       if (client->subclient >= 0)
+               client->oserver->clients[client->subclient]->oracle = -1;
+
+       /* We had an oracle? */
+       if (client->oracle >= 0)
+               client->oserver->clients[client->oracle]->subclient = -1;
+
+       assert(client->oserver->clients[client->id] == client);
+       client->oserver->clients[client->id] = NULL;
+       return 0;
+}
+
+static void add_client(struct tevent_context *ev,
+                      struct tevent_fd *fde, uint16_t flags, void *_oserver)
+{
+       struct oserver *oserver = _oserver;
+       struct client *client;
+
+       client = talloc(oserver, struct client);
+       client->fd = accept(oserver->fd, NULL, 0);
+       if (client->fd < 0)
+               err(1, "Accepting client connection");
+
+       client->state = SENDING_GREETING;
+       client->bytes_sent = 0;
+       client->question = talloc_strdup(client, "");
+       client->oserver = oserver;
+       client->oracle = -1;
+       client->subclient = -1;
+       client->answer = talloc_strdup(client, "");
+       client->fde = tevent_add_fd(ev, client, client->fd,
+                                   state_flag_map[client->state],
+                                   service_client, client);
+       tevent_fd_set_auto_close(client->fde);
+
+       /* Find empty slot in array for this client. */
+       for (client->id = 0; oserver->clients[client->id]; client->id++);
+       oserver->clients[client->id] = client;
+       talloc_set_destructor(client, cleanup_client);
+
+       /* Full?  Stop listening... */
+       if (client->id == ARRAY_SIZE(oserver->clients)-1)
+               tevent_fd_set_flags(oserver->fde, 0);
+}
+
+static void clear_clients(struct oserver *oserver)
+{
+       memset(oserver->clients, 0,
+              ARRAY_SIZE(oserver->clients) * sizeof(oserver->clients[0]));
+}
+
+static int destroy_oserver(struct oserver *oserver)
+{
+       close(oserver->fd);
+       return 0;
+}
+
+static void talloc_dump(struct tevent_context *ev,
+                       struct tevent_signal *se,
+                       int signum,
+                       int count,
+                       void *siginfo,
+                       void *_oserver)
+{
+       struct oserver *oserver = _oserver;
+       FILE *f;
+
+       /* Fork off a child for the report, so we aren't stopped. */
+       if (fork() == 0) {
+               f = fopen("/var/run/oserver/talloc.dump", "w");
+               if (f) {
+                       talloc_report_full(oserver, f);
+                       fclose(f);
                }
-               if (buf[i] == '\n' || buf[i] == '\r')
-                       break;
-               buf[i] = toupper(buf[i]);
+               _exit(0);
+       }
+}
+
+static void dump(struct tevent_context *ev,
+                struct tevent_signal *se,
+                int signum,
+                int count,
+                void *siginfo,
+                void *_oserver)
+{
+       struct oserver *oserver = _oserver;
+       char *str;
+       int fd;
+
+       str = cdump_bundle(ev, cdump_struct_oserver, oserver);
+       fd = open(oserver->dumpfile, O_CREAT|O_TRUNC|O_WRONLY, 0600);
+       write(fd, str, strlen(str));
+       close(fd);
+       talloc_free(str);
+       if (oserver->argv)
+               execvp(oserver->argv[0], oserver->argv);
+}
+
+static bool load_file(struct oserver *oserver, const char *file)
+{
+       char *str;
+
+       if (!file)
+               return false;
+
+       str = grab_file(oserver, file, NULL);
+       if (!str)
+               return false;
+
+       if (!cdump_unbundle(oserver, cdump_struct_oserver, oserver, str)) {
+               talloc_free(str);
+               return false;
        }
-       buf[i] = '\0';
+       talloc_free(str);
+       return true;
+}
+
+static bool complete_server(struct tevent_context *ev,
+                           struct oserver *oserver, const char *dumpfile)
+{
+       /* Re-set this even if restored from file, in case it changed. */
+       oserver->dumpfile = dumpfile;
+       if (oserver->dumpfile)
+               tevent_add_signal(ev, oserver, SIGHUP, SA_RESTART,
+                                 dump, oserver);
 
-       if (!write_all(fd, "Louder, like this: '",
-                      strlen("Louder, like this: '"))
-           || !write_all(fd, buf, i)
-           || !write_all(fd, "'\r\n", strlen("'\r\n")))
+       /* Don't kill us if client dies. */
+       signal(SIGPIPE, SIG_IGN);
+
+       /* Show talloc tree on SIGUSR1. */
+       tevent_add_signal(ev, oserver, SIGUSR1, SA_RESTART,
+                         talloc_dump, oserver);
+
+       oserver->fde = tevent_add_fd(ev, oserver, oserver->fd,
+                                    TEVENT_FD_READ, add_client, oserver);
+       if (!oserver->fde)
                return false;
        return true;
 }
 
-int oserver_setup(unsigned short port)
+struct oserver *oserver_restore(struct tevent_context *ev, const char *dumpfile)
+{
+       unsigned int i;
+       struct oserver *oserver = talloc(ev, struct oserver);
+       if (!load_file(oserver, dumpfile)) {
+               talloc_free(oserver);
+               return NULL;
+       }
+
+       /* Restore ignored fields in clients, and talloc hierarchy. */
+       for (i = 0; i < ARRAY_SIZE(oserver->clients); i++) {
+               struct client *client = oserver->clients[i];
+               if (!client)
+                       continue;
+               /* These two were marked CDUMP_IGNORE. */
+               client->oserver = oserver;
+               client->fde = tevent_add_fd(ev, client, client->fd,
+                                           state_flag_map[client->state],
+                                           service_client, client);
+               tevent_fd_set_auto_close(client->fde);
+               /* cdump knows nothing of talloc. */
+               talloc_steal(oserver, client);
+               talloc_steal(client, client->question);
+               talloc_steal(client, client->answer);
+               talloc_set_destructor(client, cleanup_client);
+       }
+
+       talloc_set_destructor(oserver, destroy_oserver);
+       if (!complete_server(ev, oserver, dumpfile)) {
+               talloc_free(oserver);
+               return NULL;
+       }
+       return oserver;
+}
+
+struct oserver *oserver_setup(struct tevent_context *ev, unsigned short port,
+                             const char *dumpfile, char *argv[])
 {
-       int sockfd;
+       struct oserver *oserver;
        int one = 1;
        union {
                struct sockaddr addr;
                struct sockaddr_in in;
        } u;
 
-       sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
-       if (sockfd < 0)
-               return -1;
+       oserver = talloc(ev, struct oserver);
+       oserver->argv = argv;
+       if (argv) {
+               /* Count the terminal NULL in argv_len. */
+               for (oserver->argv_len = 1;
+                    argv[oserver->argv_len - 1];
+                    oserver->argv_len++);
+       } else
+               oserver->argv_len = 0;
+       clear_clients(oserver);
+       oserver->fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+       if (oserver->fd < 0) {
+               talloc_free(oserver);
+               return NULL;
+       }
+
+       talloc_set_destructor(oserver, destroy_oserver);
 
-       if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)))
+       if (setsockopt(oserver->fd, SOL_SOCKET, SO_REUSEADDR,
+                      &one, sizeof(one)))
                warn("Setting socket reuse");
 
        u.in.sin_family = AF_INET;
        u.in.sin_port = htons(port);
        u.in.sin_addr.s_addr = INADDR_ANY;
-       if (bind(sockfd, &u.addr, sizeof(u.in)) == -1) {
-               close_noerr(sockfd);
-               return -1;
+       if (bind(oserver->fd, &u.addr, sizeof(u.in)) == -1) {
+               talloc_free(oserver);
+               return NULL;
        }
 
-       if (listen(sockfd, 0) != 0) {
-               close_noerr(sockfd);
-               return -1;
+       if (listen(oserver->fd, 0) != 0) {
+               talloc_free(oserver);
+               return NULL;
        }
-       return sockfd;
+
+       if (!complete_server(ev, oserver, dumpfile)) {
+               talloc_free(oserver);
+               return NULL;
+       }
+
+       return oserver;
 }