write flags value to return to the rest of program in preparation for flush
[nbd.git] / nbd-server.c
index a11e37a..cd584f0 100644 (file)
@@ -116,6 +116,9 @@ gchar* rungroup=NULL;
 /** whether to export using the old negotiation protocol (port-based) */
 gboolean do_oldstyle=FALSE;
 
+/* Whether we should avoid forking */
+int dontfork = 0;
+
 /** Logging macros, now nothing goes to syslog unless you say ISSERVER */
 #ifdef ISSERVER
 #define msg2(a,b) syslog(a,b)
@@ -150,7 +153,7 @@ gboolean do_oldstyle=FALSE;
 #define OFFT_MAX ~((off_t)1<<(sizeof(off_t)*8-1))
 #define LINELEN 256      /**< Size of static buffer used to read the
                               authorization file (yuck) */
-#define BUFSIZE (1024*1024) /**< Size of buffer that can hold requests */
+#define BUFSIZE ((1024*1024)+sizeof(struct nbd_reply)) /**< Size of buffer that can hold requests */
 #define DIFFPAGESIZE 4096 /**< diff file uses those chunks */
 #define F_READONLY 1      /**< flag to tell us a file is readonly */
 #define F_MULTIFILE 2    /**< flag to tell us a file is exported using -m */
@@ -204,6 +207,7 @@ typedef struct {
        gchar* postrun;      /**< command that will be ran after the client
                                  disconnects */
        gchar* servename;    /**< name of the export as selected by nbd-client */
+       int max_connections; /**< maximum number of opened connections */
 } SERVER;
 
 /**
@@ -319,7 +323,7 @@ int authorized_client(CLIENT *opts) {
  * @param buf a buffer
  * @param len the number of bytes to be read
  **/
-inline void readit(int f, void *buf, size_t len) {
+static inline void readit(int f, void *buf, size_t len) {
        ssize_t res;
        while (len > 0) {
                DEBUG("*");
@@ -341,7 +345,7 @@ inline void readit(int f, void *buf, size_t len) {
  * @param buf a buffer containing data
  * @param len the number of bytes to be written
  **/
-inline void writeit(int f, void *buf, size_t len) {
+static inline void writeit(int f, void *buf, size_t len) {
        ssize_t res;
        while (len > 0) {
                DEBUG("+");
@@ -358,14 +362,15 @@ inline void writeit(int f, void *buf, size_t len) {
  */
 void usage() {
        printf("This is nbd-server version " VERSION "\n");
-       printf("Usage: [ip:|ip6@]port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-C configuration file] [-p PID file name] [-o section name]\n"
+       printf("Usage: [ip:|ip6@]port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-C configuration file] [-p PID file name] [-o section name] [-M max connections]\n"
               "\t-r|--read-only\t\tread only\n"
               "\t-m|--multi-file\t\tmultiple file\n"
               "\t-c|--copy-on-write\tcopy on write\n"
               "\t-C|--config-file\tspecify an alternate configuration file\n"
               "\t-l|--authorize-file\tfile with list of hosts that are allowed to\n\t\t\t\tconnect.\n"
               "\t-p|--pid-file\t\tspecify a filename to write our PID to\n"
-              "\t-o|--output-config\toutput a config file section for what you\n\t\t\t\tspecified on the command line, with the\n\t\t\t\tspecified section name\n\n"
+              "\t-o|--output-config\toutput a config file section for what you\n\t\t\t\tspecified on the command line, with the\n\t\t\t\tspecified section name\n"
+              "\t-M|--max-connections\tspecify the maximum number of opened connections\n\n"
               "\tif port is set to 0, stdin is used (for running from inetd)\n"
               "\tif file_to_export contains '%%s', it is substituted with the IP\n"
               "\t\taddress of the machine trying to connect\n" 
@@ -411,10 +416,12 @@ SERVER* cmdline(int argc, char *argv[]) {
                {"read-only", no_argument, NULL, 'r'},
                {"multi-file", no_argument, NULL, 'm'},
                {"copy-on-write", no_argument, NULL, 'c'},
+               {"dont-fork", no_argument, NULL, 'd'},
                {"authorize-file", required_argument, NULL, 'l'},
                {"config-file", required_argument, NULL, 'C'},
                {"pid-file", required_argument, NULL, 'p'},
                {"output-config", required_argument, NULL, 'o'},
+               {"max-connection", required_argument, NULL, 'M'},
                {0,0,0,0}
        };
        SERVER *serve;
@@ -431,7 +438,7 @@ SERVER* cmdline(int argc, char *argv[]) {
        serve=g_new0(SERVER, 1);
        serve->authname = g_strdup(default_authname);
        serve->virtstyle=VIRT_IPLIT;
-       while((c=getopt_long(argc, argv, "-C:cl:mo:rp:", long_options, &i))>=0) {
+       while((c=getopt_long(argc, argv, "-C:cdl:mo:rp:M:", long_options, &i))>=0) {
                switch (c) {
                case 1:
                        /* non-option argument */
@@ -500,6 +507,9 @@ SERVER* cmdline(int argc, char *argv[]) {
                case 'c': 
                        serve->flags |=F_COPYONWRITE;
                        break;
+               case 'd': 
+                       dontfork = 1;
+                       break;
                case 'C':
                        g_free(config_file_pos);
                        config_file_pos=g_strdup(optarg);
@@ -508,6 +518,9 @@ SERVER* cmdline(int argc, char *argv[]) {
                        g_free(serve->authname);
                        serve->authname=g_strdup(optarg);
                        break;
+               case 'M':
+                       serve->max_connections = strtol(optarg, NULL, 0);
+                       break;
                default:
                        usage();
                        exit(EXIT_FAILURE);
@@ -593,8 +606,9 @@ SERVER* dup_serve(SERVER *s) {
                serve->authname = strdup(s->authname);
 
        serve->flags = s->flags;
-       serve->socket = serve->socket;
-       serve->socket_family = serve->socket_family;
+       serve->socket = s->socket;
+       serve->socket_family = s->socket_family;
+       serve->virtstyle = s->virtstyle;
        serve->cidrlen = s->cidrlen;
 
        if(s->prerun)
@@ -606,6 +620,8 @@ SERVER* dup_serve(SERVER *s) {
        if(s->servename)
                serve->servename = g_strdup(s->servename);
 
+       serve->max_connections = s->max_connections;
+
        return serve;
 }
 
@@ -691,20 +707,21 @@ GArray* parse_cfile(gchar* f, GError** e) {
        SERVER s;
        gchar *virtstyle=NULL;
        PARAM lp[] = {
-               { "exportname", TRUE,   PARAM_STRING,   NULL, 0 },
-               { "port",       TRUE,   PARAM_INT,      NULL, 0 },
-               { "authfile",   FALSE,  PARAM_STRING,   NULL, 0 },
-               { "filesize",   FALSE,  PARAM_INT,      NULL, 0 },
-               { "virtstyle",  FALSE,  PARAM_STRING,   NULL, 0 },
-               { "prerun",     FALSE,  PARAM_STRING,   NULL, 0 },
-               { "postrun",    FALSE,  PARAM_STRING,   NULL, 0 },
-               { "readonly",   FALSE,  PARAM_BOOL,     NULL, F_READONLY },
-               { "multifile",  FALSE,  PARAM_BOOL,     NULL, F_MULTIFILE },
-               { "copyonwrite", FALSE, PARAM_BOOL,     NULL, F_COPYONWRITE },
-               { "sparse_cow", FALSE,  PARAM_BOOL,     NULL, F_SPARSE },
-               { "sdp",        FALSE,  PARAM_BOOL,     NULL, F_SDP },
-               { "sync",       FALSE,  PARAM_BOOL,     NULL, F_SYNC },
-               { "listenaddr", FALSE,  PARAM_STRING,   NULL, 0 },
+               { "exportname", TRUE,   PARAM_STRING,   &(s.exportname),        0 },
+               { "port",       TRUE,   PARAM_INT,      &(s.port),              0 },
+               { "authfile",   FALSE,  PARAM_STRING,   &(s.authname),          0 },
+               { "filesize",   FALSE,  PARAM_INT,      &(s.expected_size),     0 },
+               { "virtstyle",  FALSE,  PARAM_STRING,   &(virtstyle),           0 },
+               { "prerun",     FALSE,  PARAM_STRING,   &(s.prerun),            0 },
+               { "postrun",    FALSE,  PARAM_STRING,   &(s.postrun),           0 },
+               { "readonly",   FALSE,  PARAM_BOOL,     &(s.flags),             F_READONLY },
+               { "multifile",  FALSE,  PARAM_BOOL,     &(s.flags),             F_MULTIFILE },
+               { "copyonwrite", FALSE, PARAM_BOOL,     &(s.flags),             F_COPYONWRITE },
+               { "sparse_cow", FALSE,  PARAM_BOOL,     &(s.flags),             F_SPARSE },
+               { "sdp",        FALSE,  PARAM_BOOL,     &(s.flags),             F_SDP },
+               { "sync",       FALSE,  PARAM_BOOL,     &(s.flags),             F_SYNC },
+               { "listenaddr", FALSE,  PARAM_STRING,   &(s.listenaddr),        0 },
+               { "maxconnections", FALSE, PARAM_INT,   &(s.max_connections),   0 },
        };
        const int lp_size=sizeof(lp)/sizeof(PARAM);
        PARAM gp[] = {
@@ -744,17 +761,6 @@ GArray* parse_cfile(gchar* f, GError** e) {
        groups = g_key_file_get_groups(cfile, NULL);
        for(i=0;groups[i];i++) {
                memset(&s, '\0', sizeof(SERVER));
-               lp[0].target=&(s.exportname);
-               lp[1].target=&(s.port);
-               lp[2].target=&(s.authname);
-               lp[3].target=&(s.expected_size);
-               lp[4].target=&(virtstyle);
-               lp[5].target=&(s.prerun);
-               lp[6].target=&(s.postrun);
-               lp[7].target=lp[8].target=lp[9].target=
-                               lp[10].target=lp[11].target=
-                               lp[12].target=&(s.flags);
-               lp[13].target=&(s.listenaddr);
 
                /* After the [generic] group, start parsing exports */
                if(i==1) {
@@ -1298,9 +1304,11 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
                                client->exportsize = OFFT_MAX;
                                client->net = net;
                                client->modern = TRUE;
+                               free(name);
                                return client;
                        }
                }
+               free(name);
                return NULL;
        }
        /* common */
@@ -1354,7 +1362,10 @@ int mainloop(CLIENT *client) {
        reply.error = 0;
        while (go_on) {
                char buf[BUFSIZE];
+               char* p;
                size_t len;
+               size_t currlen;
+               size_t writelen;
 #ifdef DODBG
                i++;
                printf("%d: ", i);
@@ -1379,8 +1390,12 @@ int mainloop(CLIENT *client) {
 
                if (request.magic != htonl(NBD_REQUEST_MAGIC))
                        err("Not enough magic.");
-               if (len > BUFSIZE + sizeof(struct nbd_reply))
-                       err("Request too big!");
+               if (len > BUFSIZE - sizeof(struct nbd_reply)) {
+                       currlen = BUFSIZE - sizeof(struct nbd_reply);
+                       msg2(LOG_INFO, "oversized request (this is not a problem)");
+               } else {
+                       currlen = len;
+               }
 #ifdef DODBG
                printf("%s from %llu (%llu) len %d, ", request.type ? "WRITE" :
                                "READ", (unsigned long long)request.from,
@@ -1401,35 +1416,47 @@ int mainloop(CLIENT *client) {
 
                if (request.type==NBD_CMD_WRITE) {
                        DEBUG("wr: net->buf, ");
-                       readit(client->net, buf, len);
-                       DEBUG("buf->exp, ");
-                       if ((client->server->flags & F_READONLY) ||
-                           (client->server->flags & F_AUTOREADONLY)) {
-                               DEBUG("[WRITE to READONLY!]");
-                               ERROR(client, reply, EPERM);
-                               continue;
-                       }
-                       if (expwrite(request.from, buf, len, client)) {
-                               DEBUG("Write failed: %m" );
-                               ERROR(client, reply, errno);
-                               continue;
+                       while(len > 0) {
+                               readit(client->net, buf, currlen);
+                               DEBUG("buf->exp, ");
+                               if ((client->server->flags & F_READONLY) ||
+                                   (client->server->flags & F_AUTOREADONLY)) {
+                                       DEBUG("[WRITE to READONLY!]");
+                                       ERROR(client, reply, EPERM);
+                                       continue;
+                               }
+                               if (expwrite(request.from, buf, len, client)) {
+                                       DEBUG("Write failed: %m" );
+                                       ERROR(client, reply, errno);
+                                       continue;
+                               }
+                               SEND(client->net, reply);
+                               DEBUG("OK!\n");
+                               len -= currlen;
+                               currlen = (len < BUFSIZE) ? len : BUFSIZE;
                        }
-                       SEND(client->net, reply);
-                       DEBUG("OK!\n");
                        continue;
                }
                /* READ */
 
                DEBUG("exp->buf, ");
-               if (expread(request.from, buf + sizeof(struct nbd_reply), len, client)) {
-                       DEBUG("Read failed: %m");
-                       ERROR(client, reply, errno);
-                       continue;
-               }
-
-               DEBUG("buf->net, ");
                memcpy(buf, &reply, sizeof(struct nbd_reply));
-               writeit(client->net, buf, len + sizeof(struct nbd_reply));
+               p = buf + sizeof(struct nbd_reply);
+               writelen = currlen + sizeof(struct nbd_reply);
+               while(len > 0) {
+                       if (expread(request.from, p, currlen, client)) {
+                               DEBUG("Read failed: %m");
+                               ERROR(client, reply, errno);
+                               continue;
+                       }
+
+                       DEBUG("buf->net, ");
+                       writeit(client->net, buf, writelen);
+                       len -= currlen;
+                       currlen = (len < BUFSIZE) ? len : BUFSIZE;
+                       p = buf;
+                       writelen = currlen;
+               }
                DEBUG("OK!\n");
        }
        return 0;
@@ -1716,7 +1743,7 @@ int serveloop(GArray* servers) {
                memcpy(&rset, &mset, sizeof(fd_set));
                if(select(max+1, &rset, NULL, NULL, NULL)>0) {
                        int net = 0;
-                       SERVER* serve;
+                       SERVER* serve=NULL;
 
                        DEBUG("accept, ");
                        if(FD_ISSET(modernsock, &rset)) {
@@ -1727,7 +1754,9 @@ int serveloop(GArray* servers) {
                                        err_nonfatal("negotiation failed");
                                        close(net);
                                        net=0;
+                                       continue;
                                }
+                               serve = client->server;
                        }
                        for(i=0;i<servers->len && !net;i++) {
                                serve=&(g_array_index(servers, SERVER, i));
@@ -1739,6 +1768,12 @@ int serveloop(GArray* servers) {
                        if(net) {
                                int sock_flags;
 
+                               if(serve->max_connections > 0 &&
+                                  g_hash_table_size(children) >= serve->max_connections) {
+                                       msg2(LOG_INFO, "Max connections reached");
+                                       close(net);
+                                       continue;
+                               }
                                if((sock_flags = fcntl(net, F_GETFL, 0))==-1) {
                                        err("fcntl F_GETFL");
                                }
@@ -1759,31 +1794,33 @@ int serveloop(GArray* servers) {
                                }
                                msg2(LOG_INFO,"Authorized client") ;
                                pid=g_malloc(sizeof(pid_t));
-#ifndef NOFORK
-                               if ((*pid=fork())<0) {
-                                       msg3(LOG_INFO,"Could not fork (%s)",strerror(errno)) ;
-                                       close(net);
-                                       continue;
-                               }
-                               if (*pid>0) { /* parent */
-                                       close(net);
-                                       g_hash_table_insert(children, pid, pid);
-                                       continue;
-                               }
-                               /* child */
-                               g_hash_table_destroy(children);
-                               for(i=0;i<servers->len;i++) {
-                                       serve=&g_array_index(servers, SERVER, i);
-                                       close(serve->socket);
+
+                               if (!dontfork) {
+                                       if ((*pid=fork())<0) {
+                                               msg3(LOG_INFO,"Could not fork (%s)",strerror(errno)) ;
+                                               close(net);
+                                               continue;
+                                       }
+                                       if (*pid>0) { /* parent */
+                                               close(net);
+                                               g_hash_table_insert(children, pid, pid);
+                                               continue;
+                                       }
+                                       /* child */
+                                       g_hash_table_destroy(children);
+                                       for(i=0;i<servers->len;i++) {
+                                               serve=&g_array_index(servers, SERVER, i);
+                                               close(serve->socket);
+                                       }
+                                       /* FALSE does not free the
+                                          actual data. This is required,
+                                          because the client has a
+                                          direct reference into that
+                                          data, and otherwise we get a
+                                          segfault... */
+                                       g_array_free(servers, FALSE);
                                }
-                               /* FALSE does not free the
-                               actual data. This is required,
-                               because the client has a
-                               direct reference into that
-                               data, and otherwise we get a
-                               segfault... */
-                               g_array_free(servers, FALSE);
-#endif // NOFORK
+
                                msg2(LOG_INFO,"Starting to serve");
                                serveconnection(client);
                                exit(EXIT_SUCCESS);
@@ -1950,7 +1987,7 @@ void setup_servers(GArray* servers) {
  *     is only used to create a PID file of the form
  *     /var/run/nbd-server.&lt;port&gt;.pid; it's not modified in any way.
  **/
-#if !defined(NODAEMON) && !defined(NOFORK)
+#if !defined(NODAEMON)
 void daemonize(SERVER* serve) {
        FILE*pidf;
 
@@ -1979,7 +2016,7 @@ void daemonize(SERVER* serve) {
 }
 #else
 #define daemonize(serve)
-#endif /* !defined(NODAEMON) && !defined(NOFORK) */
+#endif /* !defined(NODAEMON) */
 
 /*
  * Everything beyond this point (in the file) is run in non-daemon mode.
@@ -2118,7 +2155,8 @@ int main(int argc, char *argv[]) {
                g_message("No configured exports; quitting.");
                exit(EXIT_FAILURE);
        }
-       daemonize(serve);
+       if (!dontfork)
+               daemonize(serve);
        setup_servers(servers);
        dousers();
        serveloop(servers);