copy handle on all requests
[nbd.git] / nbd-server.c
index ea446db..4122cef 100644 (file)
 #define MY_NAME "nbd_server"
 #include "cliserv.h"
 
+#ifdef WITH_SDP
+#include <sdp_inet.h>
+#endif
+
 /** Default position of the config file */
 #ifndef SYSCONFDIR
 #define SYSCONFDIR "/etc"
@@ -112,6 +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)
@@ -130,11 +137,13 @@ gboolean do_oldstyle=FALSE;
 #define DEBUG2( a,b ) printf( a,b )
 #define DEBUG3( a,b,c ) printf( a,b,c )
 #define DEBUG4( a,b,c,d ) printf( a,b,c,d )
+#define DEBUG5( a,b,c,d,e ) printf( a,b,c,d,e )
 #else
 #define DEBUG( a )
 #define DEBUG2( a,b ) 
 #define DEBUG3( a,b,c ) 
 #define DEBUG4( a,b,c,d ) 
+#define DEBUG5( a,b,c,d,e ) 
 #endif
 #ifndef PACKAGE_VERSION
 #define PACKAGE_VERSION ""
@@ -146,7 +155,7 @@ 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 */
@@ -156,6 +165,9 @@ gboolean do_oldstyle=FALSE;
 #define F_SPARSE 16      /**< flag to tell us copyronwrite should use a sparse file */
 #define F_SDP 32         /**< flag to tell us the export should be done using the Socket Direct Protocol for RDMA */
 #define F_SYNC 64        /**< Whether to fsync() after a write */
+#define F_FLUSH 128      /**< Whether server wants FLUSH to be sent by the client */
+#define F_FUA 256        /**< Whether server wants FUA to be sent by the client */
+#define F_ROTATIONAL 512  /**< Whether server wants the client to implement the elevator algorithm */
 GHashTable *children;
 char pidfname[256]; /**< name of our PID file */
 char pidftemplate[256]; /**< template to be used for the filename of the PID file */
@@ -200,6 +212,7 @@ 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;
 
 /**
@@ -315,7 +328,7 @@ 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("*");
@@ -337,7 +350,7 @@ 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("+");
@@ -354,14 +367,15 @@ 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" 
@@ -407,10 +421,12 @@ 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;
@@ -427,7 +443,7 @@ 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 */
@@ -496,6 +512,9 @@ 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);
@@ -504,6 +523,9 @@ 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);
@@ -589,8 +611,9 @@ 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)
@@ -602,6 +625,8 @@ SERVER* dup_serve(SERVER *s) {
        if(s->servename)
                serve->servename = g_strdup(s->servename);
 
+       serve->max_connections = s->max_connections;
+
        return serve;
 }
 
@@ -687,20 +712,24 @@ 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 },
+               { "flush",      FALSE,  PARAM_BOOL,     &(s.flags),             F_FLUSH },
+               { "fua",        FALSE,  PARAM_BOOL,     &(s.flags),             F_FUA },
+               { "rotational", FALSE,  PARAM_BOOL,     &(s.flags),             F_ROTATIONAL },
+               { "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[] = {
@@ -740,17 +769,6 @@ 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) {
@@ -1045,7 +1063,7 @@ void myseek(int handle,off_t a) {
  * @param client The client we're serving for
  * @return The number of bytes actually written, or -1 in case of an error
  **/
-ssize_t rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client) {
+ssize_t rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client, int fua) {
        int fhandle;
        off_t foffset;
        size_t maxbytes;
@@ -1056,12 +1074,20 @@ ssize_t rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client) {
        if(maxbytes && len > maxbytes)
                len = maxbytes;
 
-       DEBUG4("(WRITE to fd %d offset %llu len %u), ", fhandle, foffset, len);
+       DEBUG5("(WRITE to fd %d offset %llu len %u fua %d), ", fhandle, foffset, len, fua);
 
        myseek(fhandle, foffset);
        retval = write(fhandle, buf, len);
        if(client->server->flags & F_SYNC) {
                fsync(fhandle);
+       } else if (fua) {
+#ifdef USE_SYNC_FILE_RANGE
+               sync_file_range(fhandle, foffset, len,
+                               SYNC_FILE_RANGE_WAIT_BEFORE | SYNC_FILE_RANGE_WRITE |
+                               SYNC_FILE_RANGE_WAIT_AFTER);
+#else
+               fdatasync(fhandle);
+#endif
        }
        return retval;
 }
@@ -1070,10 +1096,10 @@ ssize_t rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client) {
  * Call rawexpwrite repeatedly until all data has been written.
  * @return 0 on success, nonzero on failure
  **/
-int rawexpwrite_fully(off_t a, char *buf, size_t len, CLIENT *client) {
+int rawexpwrite_fully(off_t a, char *buf, size_t len, CLIENT *client, int fua) {
        ssize_t ret=0;
 
-       while(len > 0 && (ret=rawexpwrite(a, buf, len, client)) > 0 ) {
+       while(len > 0 && (ret=rawexpwrite(a, buf, len, client, fua)) > 0 ) {
                a += ret;
                buf += ret;
                len -= ret;
@@ -1174,7 +1200,7 @@ int expread(off_t a, char *buf, size_t len, CLIENT *client) {
  * @param client The client we're going to write for.
  * @return 0 on success, nonzero on failure
  **/
-int expwrite(off_t a, char *buf, size_t len, CLIENT *client) {
+int expwrite(off_t a, char *buf, size_t len, CLIENT *client, int fua) {
        char pagebuf[DIFFPAGESIZE];
        off_t mapcnt,mapl,maph;
        off_t wrlen,rdlen; 
@@ -1182,7 +1208,7 @@ int expwrite(off_t a, char *buf, size_t len, CLIENT *client) {
        off_t offset;
 
        if (!(client->server->flags & F_COPYONWRITE))
-               return(rawexpwrite_fully(a, buf, len, client)); 
+               return(rawexpwrite_fully(a, buf, len, client, fua)); 
        DEBUG3("Asked to write %d bytes at %llu.\n", len, (unsigned long long)a);
 
        mapl=a/DIFFPAGESIZE ; maph=(a+len-1)/DIFFPAGESIZE ;
@@ -1215,6 +1241,33 @@ int expwrite(off_t a, char *buf, size_t len, CLIENT *client) {
                }                                                   
                len-=wrlen ; a+=wrlen ; buf+=wrlen ;
        }
+       if (client->server->flags & F_SYNC) {
+               fsync(client->difffile);
+       } else if (fua) {
+               /* open question: would it be cheaper to do multiple sync_file_ranges?
+                  as we iterate through the above?
+                */
+               fdatasync(client->difffile);
+       }
+       return 0;
+}
+
+int expflush(CLIENT *client) {
+       int fhandle;
+       off_t foffset;
+       size_t maxbytes;
+       gint i;
+
+        if (client->server->flags & F_COPYONWRITE) {
+               return fsync(client->difffile);
+       }
+       
+       for (i = 0; i < client->export->len; i++) {
+               FILE_INFO fi = g_array_index(client->export, FILE_INFO, i);
+               if (fsync(fi.fhandle) < 0)
+                       return -1;
+       }
+       
        return 0;
 }
 
@@ -1232,14 +1285,17 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
 
        memset(zeros, '\0', sizeof(zeros));
        if(!client || !client->modern) {
+               /* common */
                if (write(net, INIT_PASSWD, 8) < 0) {
                        err_nonfatal("Negotiation failed: %m");
                        if(client)
                                exit(EXIT_FAILURE);
                }
-               if(client && client->modern) {
+               if(!client || client->modern) {
+                       /* modern */
                        magic = htonll(opts_magic);
                } else {
+                       /* oldstyle */
                        magic = htonll(cliserv_magic);
                }
                if (write(net, &magic, sizeof(magic)) < 0) {
@@ -1249,6 +1305,7 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
                }
        }
        if(!client) {
+               /* modern */
                uint32_t reserved;
                uint32_t opt;
                uint32_t namelen;
@@ -1257,25 +1314,31 @@ CLIENT* negotiate(int net, CLIENT *client, GArray* servers) {
 
                if(!servers)
                        err("programmer error");
-               write(net, &smallflags, sizeof(uint16_t));
-               read(net, &reserved, sizeof(reserved));
-               read(net, &magic, sizeof(magic));
+               if (write(net, &smallflags, sizeof(uint16_t)) < 0)
+                       err("Negotiation failed: %m");
+               if (read(net, &reserved, sizeof(reserved)) < 0)
+                       err("Negotiation failed: %m");
+               if (read(net, &magic, sizeof(magic)) < 0)
+                       err("Negotiation failed: %m");
                magic = ntohll(magic);
                if(magic != opts_magic) {
                        close(net);
                        return NULL;
                }
-               read(net, &opt, sizeof(opt));
+               if (read(net, &opt, sizeof(opt)) < 0)
+                       err("Negotiation failed: %m");
                opt = ntohl(opt);
                if(opt != NBD_OPT_EXPORT_NAME) {
                        close(net);
                        return NULL;
                }
-               read(net, &namelen, sizeof(namelen));
+               if (read(net, &namelen, sizeof(namelen)) < 0)
+                       err("Negotiation failed: %m");
                namelen = ntohl(namelen);
                name = malloc(namelen+1);
-               name[namelen+1]=0;
-               read(net, name, namelen);
+               name[namelen]=0;
+               if (read(net, name, namelen) < 0)
+                       err("Negotiation failed: %m");
                for(i=0; i<servers->len; i++) {
                        SERVER* serve = &(g_array_index(servers, SERVER, i));
                        if(!strcmp(serve->servename, name)) {
@@ -1284,26 +1347,39 @@ 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 */
        size_host = htonll((u64)(client->exportsize));
        if (write(net, &size_host, 8) < 0)
                err("Negotiation failed: %m");
        if (client->server->flags & F_READONLY)
                flags |= NBD_FLAG_READ_ONLY;
+       if (client->server->flags & F_FLUSH)
+               flags |= NBD_FLAG_SEND_FLUSH;
+       if (client->server->flags & F_FUA)
+               flags |= NBD_FLAG_SEND_FUA;
+       if (client->server->flags & F_ROTATIONAL)
+               flags |= NBD_FLAG_ROTATIONAL;
        if (!client->modern) {
+               /* oldstyle */
                flags = htonl(flags);
                if (write(client->net, &flags, 4) < 0)
                        err("Negotiation failed: %m");
        } else {
+               /* modern */
                smallflags = (uint16_t)(flags & ~((uint16_t)0));
                smallflags = htons(smallflags);
                if (write(client->net, &smallflags, sizeof(smallflags)) < 0) {
                        err("Negotiation failed: %m");
                }
        }
+       /* common */
        if (write(client->net, zeros, 124) < 0)
                err("Negotiation failed: %m");
        return NULL;
@@ -1335,7 +1411,11 @@ int mainloop(CLIENT *client) {
        reply.error = 0;
        while (go_on) {
                char buf[BUFSIZE];
+               char* p;
                size_t len;
+               size_t currlen;
+               size_t writelen;
+               uint16_t command;
 #ifdef DODBG
                i++;
                printf("%d: ", i);
@@ -1343,8 +1423,9 @@ int mainloop(CLIENT *client) {
                readit(client->net, &request, sizeof(request));
                request.from = ntohll(request.from);
                request.type = ntohl(request.type);
+               command = request.type & NBD_CMD_MASK_COMMAND;
 
-               if (request.type==NBD_CMD_DISC) {
+               if (command==NBD_CMD_DISC) {
                        msg2(LOG_INFO, "Disconnect request received.");
                        if (client->server->flags & F_COPYONWRITE) { 
                                if (client->difmap) g_free(client->difmap) ;
@@ -1360,38 +1441,62 @@ 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" :
+               printf("%s from %llu (%llu) len %d, ", command ? "WRITE" :
                                "READ", (unsigned long long)request.from,
                                (unsigned long long)request.from / 512, len);
 #endif
                memcpy(reply.handle, request.handle, sizeof(reply.handle));
-               if ((request.from + len) > (OFFT_MAX)) {
-                       DEBUG("[Number too large!]");
-                       ERROR(client, reply, EINVAL);
-                       continue;
-               }
 
-               if (((ssize_t)((off_t)request.from + len) > client->exportsize)) {
-                       DEBUG("[RANGE!]");
-                       ERROR(client, reply, EINVAL);
-                       continue;
+               if ((command==NBD_CMD_WRITE) || (command==NBD_CMD_READ)) {
+                       if ((request.from + len) > (OFFT_MAX)) {
+                               DEBUG("[Number too large!]");
+                               ERROR(client, reply, EINVAL);
+                               continue;
+                       }
+
+                       if (((ssize_t)((off_t)request.from + len) > client->exportsize)) {
+                               DEBUG("[RANGE!]");
+                               ERROR(client, reply, EINVAL);
+                               continue;
+                       }
                }
 
-               if (request.type==NBD_CMD_WRITE) {
+               if (command==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;
+                       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,
+                                            request.type & NBD_CMD_FLAG_FUA)) {
+                                       DEBUG("Write failed: %m" );
+                                       ERROR(client, reply, errno);
+                                       continue;
+                               }
+                               SEND(client->net, reply);
+                               DEBUG("OK!\n");
+                               len -= currlen;
+                               currlen = (len < BUFSIZE) ? len : BUFSIZE;
                        }
-                       if (expwrite(request.from, buf, len, client)) {
-                               DEBUG("Write failed: %m" );
+                       continue;
+               }
+
+               if (command==NBD_CMD_FLUSH) {
+                       DEBUG("fl: ");
+                       if (expflush(client)) {
+                               DEBUG("Flush failed: %m");
                                ERROR(client, reply, errno);
                                continue;
                        }
@@ -1399,19 +1504,31 @@ int mainloop(CLIENT *client) {
                        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);
+               if (command==NBD_CMD_READ) {
+                       DEBUG("exp->buf, ");
+                       memcpy(buf, &reply, 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");
                        continue;
                }
 
-               DEBUG("buf->net, ");
-               memcpy(buf, &reply, sizeof(struct nbd_reply));
-               writeit(client->net, buf, len + sizeof(struct nbd_reply));
-               DEBUG("OK!\n");
+               DEBUG ("Ignoring unknown command\n");
        }
        return 0;
 }
@@ -1697,7 +1814,7 @@ 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)) {
@@ -1707,7 +1824,10 @@ int serveloop(GArray* servers) {
                                if(!client) {
                                        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));
@@ -1719,6 +1839,12 @@ 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");
                                }
@@ -1739,31 +1865,33 @@ 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);
@@ -1930,7 +2058,7 @@ 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;
 
@@ -1959,7 +2087,7 @@ 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.
@@ -2030,7 +2158,7 @@ void glib_message_syslog_redirect(const gchar *log_domain,
       default:
         level=LOG_ERR;
     }
-    syslog(level, message);
+    syslog(level, "%s", message);
 }
 #endif
 
@@ -2083,8 +2211,11 @@ int main(int argc, char *argv[]) {
        }
     
        if(!servers || !servers->len) {
-               g_warning("Could not parse config file: %s", 
-                               err ? err->message : "Unknown error");
+               if(err && !(err->domain == g_quark_from_string("parse_cfile")
+                               && err->code == CFILE_NOTFOUND)) {
+                       g_warning("Could not parse config file: %s", 
+                                       err ? err->message : "Unknown error");
+               }
        }
        if(serve) {
                g_warning("Specifying an export on the command line is deprecated.");
@@ -2092,10 +2223,11 @@ int main(int argc, char *argv[]) {
        }
 
        if((!serve) && (!servers||!servers->len)) {
-               g_message("Nothing to do! Bye!");
+               g_message("No configured exports; quitting.");
                exit(EXIT_FAILURE);
        }
-       daemonize(serve);
+       if (!dontfork)
+               daemonize(serve);
        setup_servers(servers);
        dousers();
        serveloop(servers);