2 * Network Block Device - server
4 * Copyright 1996-1998 Pavel Machek, distribute under GPL
5 * <pavel@atrey.karlin.mff.cuni.cz>
6 * Copyright 2001-2004 Wouter Verhelst <wouter@debian.org>
7 * Copyright 2002 Anton Altaparmakov <aia21@cam.ac.uk>
9 * Version 1.0 - hopefully 64-bit-clean
10 * Version 1.1 - merging enhancements from Josh Parsons, <josh@coombs.anu.edu.au>
11 * Version 1.2 - autodetect size of block devices, thanx to Peter T. Breuer" <ptb@it.uc3m.es>
12 * Version 1.5 - can compile on Unix systems that don't have 64 bit integer
13 * type, or don't have 64 bit file offsets by defining FS_32BIT
14 * in compile options for nbd-server *only*. This can be done
15 * with make FSCHOICE=-DFS_32BIT nbd-server. (I don't have the
16 * original autoconf input file, or I would make it a configure
17 * option.) Ken Yap <ken@nlc.net.au>.
18 * Version 1.6 - fix autodetection of block device size and really make 64 bit
19 * clean on 32 bit machines. Anton Altaparmakov <aia21@cam.ac.uk>
20 * Version 2.0 - Version synchronised with client
21 * Version 2.1 - Reap zombie client processes when they exit. Removed
22 * (uncommented) the _IO magic, it's no longer necessary. Wouter
23 * Verhelst <wouter@debian.org>
24 * Version 2.2 - Auto switch to read-only mode (usefull for floppies).
25 * Version 2.3 - Fixed code so that Large File Support works. This
26 * removes the FS_32BIT compile-time directive; define
27 * _FILE_OFFSET_BITS=64 and _LARGEFILE_SOURCE if you used to be
28 * using FS_32BIT. This will allow you to use files >2GB instead of
29 * having to use the -m option. Wouter Verhelst <wouter@debian.org>
30 * Version 2.4 - Added code to keep track of children, so that we can
31 * properly kill them from initscripts. Add a call to daemon(),
32 * so that processes don't think they have to wait for us, which is
33 * interesting for initscripts as well. Wouter Verhelst
35 * Version 2.5 - Bugfix release: forgot to reset child_arraysize to
36 * zero after fork()ing, resulting in nbd-server going berserk
37 * when it receives a signal with at least one child open. Wouter
38 * Verhelst <wouter@debian.org>
39 * 10/10/2003 - Added socket option SO_KEEPALIVE (sf.net bug 819235);
40 * rectified type of mainloop::size_host (sf.net bugs 814435 and
41 * 817385); close the PID file after writing to it, so that the
42 * daemon can actually be found. Wouter Verhelst
44 * 10/10/2003 - Size of the data "size_host" was wrong and so was not
45 * correctly put in network endianness. Many types were corrected
46 * (size_t and off_t instead of int). <vspaceg@sourceforge.net>
47 * Version 2.6 - Some code cleanup.
48 * Version 2.7 - Better build system.
49 * 11/02/2004 - Doxygenified the source, modularized it a bit. Needs a
50 * lot more work, but this is a start. Wouter Verhelst
54 /* Includes LFS defines, which defines behaviours of some of the following
55 * headers, so must come before those */
58 #include <sys/types.h>
59 #include <sys/socket.h>
61 #include <sys/wait.h> /* wait */
62 #ifdef HAVE_SYS_IOCTL_H
63 #include <sys/ioctl.h>
65 #include <sys/param.h>
66 #ifdef HAVE_SYS_MOUNT_H
67 #include <sys/mount.h> /* For BLKGETSIZE */
69 #include <signal.h> /* sigaction */
70 #include <netinet/tcp.h>
71 #include <netinet/in.h> /* sockaddr_in, htons, in_addr */
72 #include <netdb.h> /* hostent, gethostby*, getservby* */
79 #include <arpa/inet.h>
87 /* used in cliserv.h, so must come first */
88 #define MY_NAME "nbd_server"
91 /** how much space for child PIDs we have by default. Dynamically
92 allocated, and will be realloc()ed if out of space, so this should
93 probably be fair for most situations. */
94 #define DEFAULT_CHILD_ARRAY 256
96 /** Logging macros, now nothing goes to syslog unless you say ISSERVER */
98 #define msg2(a,b) syslog(a,b)
99 #define msg3(a,b,c) syslog(a,b,c)
100 #define msg4(a,b,c,d) syslog(a,b,c,d)
102 #define msg2(a,b) g_message(b)
103 #define msg3(a,b,c) g_message(b,c)
104 #define msg4(a,b,c,d) g_message(b,c,d)
107 /* Debugging macros */
110 #define DEBUG( a ) printf( a )
111 #define DEBUG2( a,b ) printf( a,b )
112 #define DEBUG3( a,b,c ) printf( a,b,c )
115 #define DEBUG2( a,b )
116 #define DEBUG3( a,b,c )
118 #ifndef PACKAGE_VERSION
119 #define PACKAGE_VERSION ""
122 * The highest value a variable of type off_t can reach.
124 /* This is starting to get ugly. If someone knows a better way to find
125 * the maximum value of a signed type *without* relying on overflow
126 * (doing so breaks on 64bit architectures), that would be nice.
128 * Actually, do we need this at all? Can't we just say '0 is autodetect', and
129 * live with it? Or better yet, use an extra flag, or so?
130 * Answer: yes, we need it, as the hunksize is defined to this when the
131 * multiple file thingy isn't used.
133 #define OFFT_MAX (((((off_t)1)<<((sizeof(off_t)-1)*8))-1)<<7)+127
134 #define LINELEN 256 /**< Size of static buffer used to read the
135 authorization file (yuck) */
136 #define BUFSIZE (1024*1024) /**< Size of buffer that can hold requests */
137 #define GIGA (1*1024*1024*1024) /**< 1 Gigabyte. Used as hunksize when doing
138 the multiple file thingy. @todo: make this a
139 configuration option. */
140 #define DIFFPAGESIZE 4096 /**< diff file uses those chunks */
141 #define F_READONLY 1 /**< flag to tell us a file is readonly */
142 #define F_MULTIFILE 2 /**< flag to tell us a file is exported using -m */
143 #define F_COPYONWRITE 4 /**< flag to tell us a file is exported using
145 #define F_AUTOREADONLY 8 /**< flag to tell us a file is set to autoreadonly */
146 GHashTable *children;
147 char pidfname[256]; /**< name of our PID file */
148 char default_authname[] = "/etc/nbd_server.allow"; /**< default name of allow file */
151 * Variables associated with a server.
154 char* exportname; /**< (unprocessed) filename of the file we're exporting */
155 off_t hunksize; /**< size of a hunk of an exported file */
156 off_t expected_size; /**< size of the exported file as it was told to
157 us through configuration */
158 unsigned int port; /**< port we're exporting this file at */
159 char* authname; /**< filename of the authorization file */
160 int flags; /**< flags associated with this exported file */
161 unsigned int timeout;/**< how long a connection may be idle
163 int socket; /**< The socket of this server. */
167 * Variables associated with a client socket.
170 off_t exportsize; /**< size of the file we're exporting */
171 char *clientname; /**< peer */
172 char *exportname; /**< (processed) filename of the file we're exporting */
173 int export[1024]; /**< array of filedescriptors of exported files;
174 only the first is actually used unless we're
175 doing the multiple file option */
176 int net; /**< The actual client socket */
177 SERVER *server; /**< The server this client is getting data from */
178 char* difffilename; /**< filename of the copy-on-write file, if any */
179 int difffile; /**< filedescriptor of copyonwrite file. @todo
180 shouldn't this be an array too? (cfr export) Or
181 make -m and -c mutually exclusive */
182 u32 difffilelen; /**< number of pages in difffile */
183 u32 *difmap; /**< see comment on the global difmap for this one */
187 * Check whether a client is allowed to connect. Works with an authorization
188 * file which contains one line per machine, no wildcards.
190 * @param name IP address of client trying to connect (in human-readable form)
191 * @return 0 - authorization refused, 1 - OK
193 int authorized_client(CLIENT *opts) {
198 if ((f=fopen(opts->server->authname,"r"))==NULL) {
199 msg4(LOG_INFO,"Can't open authorization file %s (%s).",
200 opts->server->authname,strerror(errno)) ;
204 while (fgets(line,LINELEN,f)!=NULL) {
205 if (strncmp(line,opts->clientname,strlen(opts->clientname))==0) {
215 * Read data from a file descriptor into a buffer
217 * @param f a file descriptor
218 * @param buf a buffer
219 * @param len the number of bytes to be read
221 inline void readit(int f, void *buf, size_t len) {
225 if ((res = read(f, buf, len)) <= 0)
226 err("Read failed: %m");
233 * Write data from a buffer into a filedescriptor
235 * @param f a file descriptor
236 * @param buf a buffer containing data
237 * @param len the number of bytes to be written
239 inline void writeit(int f, void *buf, size_t len) {
243 if ((res = write(f, buf, len)) <= 0)
244 err("Send failed: %m");
251 * Print out a message about how to use nbd-server. Split out to a separate
252 * function so that we can call it from multiple places
255 printf("This is nbd-server version " VERSION "\n");
256 printf("Usage: port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-a timeout_sec]\n"
257 "\t-r|--read-only\t\tread only\n"
258 "\t-m|--multi-file\t\tmultiple file\n"
259 "\t-c|--copy-on-write\tcopy on write\n"
260 "\t-l|--authorize-file\tfile with list of hosts that are allowed to\n\t\t\t\tconnect.\n"
261 "\t-a|--idle-time\t\tmaximum idle seconds; server terminates when\n\t\t\t\tidle time exceeded\n\n"
262 "\tif port is set to 0, stdin is used (for running from inetd)\n"
263 "\tif file_to_export contains '%%s', it is substituted with the IP\n"
264 "\t\taddress of the machine trying to connect\n" );
268 * Parse the command line.
270 * @todo getopt() is a great thing, and easy to use. Also, we want to
271 * create a configuration file which nbd-server will read. Maybe do (as in,
274 * @param argc the argc argument to main()
275 * @param argv the argv argument to main()
277 SERVER* cmdline(int argc, char *argv[]) {
280 struct option long_options[] = {
281 {"read-only", no_argument, NULL, 'r'},
282 {"multi-file", no_argument, NULL, 'm'},
283 {"copy-on-write", no_argument, NULL, 'c'},
284 {"authorize-file", required_argument, NULL, 'l'},
285 {"idle-time", required_argument, NULL, 'a'},
290 serve=g_malloc(sizeof(SERVER));
291 serve->hunksize=OFFT_MAX;
292 while((c=getopt_long(argc, argv, "a:cl:mr", long_options, &i))>=0) {
295 serve->flags |= F_READONLY;
298 serve->flags |= F_MULTIFILE;
299 serve->hunksize = 1*GIGA;
300 serve->authname = default_authname;
303 serve->flags |=F_COPYONWRITE;
306 serve->authname=optarg;
309 serve->timeout=strtol(optarg, NULL, 0);
317 /* What's left: the port to export, the name of the to be exported
318 * file, and, optionally, the size of the file, in that order. */
323 serve->port=strtol(argv[i], NULL, 0);
328 serve->exportname = argv[i];
331 size_t last = strlen(argv[i])-1;
332 char suffix = argv[i][last];
333 if (suffix == 'k' || suffix == 'K' ||
334 suffix == 'm' || suffix == 'M')
335 argv[i][last] = '\0';
336 es = (off_t)atol(argv[i]);
344 serve->expected_size = es;
350 * Signal handler for SIGCHLD
351 * @param s the signal we're handling (must be SIGCHLD, or something
354 void sigchld_handler(int s) {
359 while((pid=wait(status)) > 0) {
360 if(WIFEXITED(status)) {
361 msg3(LOG_INFO, "Child exited with %d", WEXITSTATUS(status));
363 i=g_hash_table_lookup(children, &pid);
365 msg3(LOG_INFO, "SIGCHLD received for an unknown child with PID %ld", (long)pid);
367 DEBUG2("Removing %d from the list of children", pid);
368 g_hash_table_remove(children, &pid);
374 * Kill a child. Called from sigterm_handler::g_hash_table_foreach.
377 * @param value the value corresponding to the above key
378 * @param user_data a pointer which we always set to 1, so that we know what
381 void killchild(gpointer key, gpointer value, gpointer user_data) {
383 int *parent=user_data;
390 * Handle SIGTERM and dispatch it to our children
391 * @param s the signal we're handling (must be SIGTERM, or something
392 * is severely wrong).
394 void sigterm_handler(int s) {
397 g_hash_table_foreach(children, killchild, &parent);
407 * Detect the size of a file.
409 * @param export An open filedescriptor
410 * @return the size of the file, or OFFT_MAX if detection was
413 off_t size_autodetect(int export) {
416 struct stat stat_buf;
419 #ifdef HAVE_SYS_MOUNT_H
420 #ifdef HAVE_SYS_IOCTL_H
422 DEBUG("looking for export size with ioctl BLKGETSIZE\n");
423 if (!ioctl(export, BLKGETSIZE, &es32) && es32) {
424 es = (off_t)es32 * (off_t)512;
427 #endif /* BLKGETSIZE */
428 #endif /* HAVE_SYS_IOCTL_H */
429 #endif /* HAVE_SYS_MOUNT_H */
431 DEBUG("looking for export size with fstat\n");
432 stat_buf.st_size = 0;
433 error = fstat(export, &stat_buf);
435 if(stat_buf.st_size > 0)
436 return (off_t)stat_buf.st_size;
438 err("fstat failed: %m");
441 DEBUG("looking for export size with lseek SEEK_END\n");
442 es = lseek(export, (off_t)0, SEEK_END);
443 if (es > ((off_t)0)) {
446 DEBUG2("lseek failed: %d", errno==EBADF?1:(errno==ESPIPE?2:(errno==EINVAL?3:4)));
449 err("Could not find size of exported block device: %m");
454 * seek to a position in a file, with error handling.
455 * @param handle a filedescriptor
456 * @param a position to seek to
457 * @todo get rid of this; lastpoint is a global variable right now, but it
458 * shouldn't be. If we pass it on as a parameter, that makes things a *lot*
461 void myseek(int handle,off_t a) {
462 if (lseek(handle, a, SEEK_SET) < 0) {
463 err("Can not seek locally!\n");
468 * Write an amount of bytes at a given offset to the right file. This
469 * abstracts the write-side of the multiple file option.
471 * @param a The offset where the write should start
472 * @param buf The buffer to write from
473 * @param len The length of buf
474 * @return The number of bytes actually written, or -1 in case of an error
476 int rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client) {
479 myseek(client->export[(int)a/client->server->hunksize],
480 a%client->server->hunksize);
481 res = write(client->export[(int)((off_t)a/(off_t)(client->server->hunksize))], buf, len);
482 return (res < 0 || (size_t)res != len);
486 * Read an amount of bytes at a given offset from the right file. This
487 * abstracts the read-side of the multiple files option.
489 * @param a The offset where the read should start
490 * @param buf A buffer to read into
491 * @param len The size of buf
492 * @return The number of bytes actually read, or -1 in case of an
495 int rawexpread(off_t a, char *buf, size_t len, CLIENT *client) {
498 myseek(client->export[(int)a/client->server->hunksize],
499 a%client->server->hunksize);
500 res = read(client->export[(int)a/client->server->hunksize], buf, len);
501 return (res < 0 || (size_t)res != len);
505 * Read an amount of bytes at a given offset from the right file. This
506 * abstracts the read-side of the copyonwrite stuff, and calls
507 * rawexpread() with the right parameters to do the actual work.
508 * @param a The offset where the read should start
509 * @param buf A buffer to read into
510 * @param len The size of buf
511 * @return The number of bytes actually read, or -1 in case of an error
513 int expread(off_t a, char *buf, size_t len, CLIENT *client) {
515 off_t mapcnt, mapl, maph, pagestart;
517 if (!(client->server->flags & F_COPYONWRITE))
518 return rawexpread(a, buf, len, client);
519 DEBUG3("Asked to read %d bytes at %Lu.\n", len, (unsigned long long)a);
521 mapl=a/DIFFPAGESIZE; maph=(a+len-1)/DIFFPAGESIZE;
523 for (mapcnt=mapl;mapcnt<=maph;mapcnt++) {
524 pagestart=mapcnt*DIFFPAGESIZE;
526 rdlen=(0<DIFFPAGESIZE-offset && len<(size_t)(DIFFPAGESIZE-offset)) ?
527 len : (size_t)DIFFPAGESIZE-offset;
528 if (client->difmap[mapcnt]!=(u32)(-1)) { /* the block is already there */
529 DEBUG3("Page %Lu is at %lu\n", (unsigned long long)mapcnt,
530 (unsigned long)(client->difmap[mapcnt]));
531 myseek(client->difffile, client->difmap[mapcnt]*DIFFPAGESIZE+offset);
532 if (read(client->difffile, buf, rdlen) != rdlen) return -1;
533 } else { /* the block is not there */
534 DEBUG2("Page %Lu is not here, we read the original one\n",
535 (unsigned long long)mapcnt);
536 if(rawexpread(a, buf, rdlen, client)) return -1;
538 len-=rdlen; a+=rdlen; buf+=rdlen;
544 * Write an amount of bytes at a given offset to the right file. This
545 * abstracts the write-side of the copyonwrite option, and calls
546 * rawexpwrite() with the right parameters to do the actual work.
548 * @param a The offset where the write should start
549 * @param buf The buffer to write from
550 * @param len The length of buf
551 * @return The number of bytes actually written, or -1 in case of an error
553 int expwrite(off_t a, char *buf, size_t len, CLIENT *client) {
554 char pagebuf[DIFFPAGESIZE];
555 off_t mapcnt,mapl,maph;
560 if (!(client->server->flags & F_COPYONWRITE))
561 return(rawexpwrite(a,buf,len, client));
562 DEBUG3("Asked to write %d bytes at %Lu.\n", len, (unsigned long long)a);
564 mapl=a/DIFFPAGESIZE ; maph=(a+len-1)/DIFFPAGESIZE ;
566 for (mapcnt=mapl;mapcnt<=maph;mapcnt++) {
567 pagestart=mapcnt*DIFFPAGESIZE ;
569 wrlen=(0<DIFFPAGESIZE-offset && len<(size_t)(DIFFPAGESIZE-offset)) ?
570 len : (size_t)DIFFPAGESIZE-offset;
572 if (client->difmap[mapcnt]!=(u32)(-1)) { /* the block is already there */
573 DEBUG3("Page %Lu is at %lu\n", (unsigned long long)mapcnt,
574 (unsigned long)(client->difmap[mapcnt])) ;
575 myseek(client->difffile,
576 client->difmap[mapcnt]*DIFFPAGESIZE+offset);
577 if (write(client->difffile, buf, wrlen) != wrlen) return -1 ;
578 } else { /* the block is not there */
579 myseek(client->difffile,client->difffilelen*DIFFPAGESIZE) ;
580 client->difmap[mapcnt]=client->difffilelen++ ;
581 DEBUG3("Page %Lu is not here, we put it at %lu\n",
582 (unsigned long long)mapcnt,
583 (unsigned long)(client->difmap[mapcnt]));
585 if (rdlen+pagestart%(client->server->hunksize) >
586 (client->server->hunksize))
587 rdlen=client->server->hunksize -
588 (pagestart%client->server->hunksize);
589 if (rawexpread(pagestart, pagebuf, rdlen, client))
591 memcpy(pagebuf+offset,buf,wrlen) ;
592 if (write(client->difffile, pagebuf, DIFFPAGESIZE) !=
596 len-=wrlen ; a+=wrlen ; buf+=wrlen ;
602 * Do the initial negotiation.
604 * @param net A socket to do the negotiation over
606 void negotiate(CLIENT *client) {
610 memset(zeros, 0, 290);
611 if (write(client->net, INIT_PASSWD, 8) < 0)
612 err("Negotiation failed: %m");
613 cliserv_magic = htonll(cliserv_magic);
614 if (write(client->net, &cliserv_magic, sizeof(cliserv_magic)) < 0)
615 err("Negotiation failed: %m");
616 size_host = htonll((u64)(client->exportsize));
617 if (write(client->net, &size_host, 8) < 0)
618 err("Negotiation failed: %m");
619 if (write(client->net, zeros, 128) < 0)
620 err("Negotiation failed: %m");
623 /** sending macro. */
624 #define SEND(net,reply) writeit( net, &reply, sizeof( reply ));
626 #define ERROR(client,reply) { reply.error = htonl(-1); SEND(client->net,reply); reply.error = 0; }
628 * Serve a file to a single client.
630 * @todo This beast needs to be split up in many tiny little manageable
631 * pieces. Preferably with a chainsaw.
633 * @param net A network socket, connected to an nbd client
636 int mainloop(CLIENT *client) {
637 struct nbd_request request;
638 struct nbd_reply reply;
644 DEBUG("Entering request loop!\n");
645 reply.magic = htonl(NBD_REPLY_MAGIC);
654 if (client->server->timeout)
655 alarm(client->server->timeout);
656 readit(client->net, &request, sizeof(request));
657 request.from = ntohll(request.from);
658 request.type = ntohl(request.type);
660 if (request.type==NBD_CMD_DISC) {
661 msg2(LOG_INFO, "Disconnect request received.");
662 if (client->difmap) g_free(client->difmap) ;
663 if (client->difffile>=0) {
664 close(client->difffile);
665 unlink(client->difffilename);
666 free(client->difffilename);
672 len = ntohl(request.len);
674 if (request.magic != htonl(NBD_REQUEST_MAGIC))
675 err("Not enough magic.");
677 err("Request too big!");
679 printf("%s from %Lu (%Lu) len %d, ", request.type ? "WRITE" :
680 "READ", (unsigned long long)request.from,
681 (unsigned long long)request.from / 512, len);
683 memcpy(reply.handle, request.handle, sizeof(reply.handle));
684 if ((request.from + len) > (OFFT_MAX)) {
685 DEBUG("[Number too large!]");
686 ERROR(client, reply);
690 if (((ssize_t)((off_t)request.from + len) > client->exportsize) ||
691 ((client->server->flags & F_READONLY) && request.type)) {
693 ERROR(client, reply);
697 if (request.type==NBD_CMD_WRITE) {
698 DEBUG("wr: net->buf, ");
699 readit(client->net, buf, len);
701 if ((client->server->flags & F_AUTOREADONLY) ||
702 expwrite(request.from, buf, len,
704 DEBUG("Write failed: %m" );
705 ERROR(client, reply);
708 SEND(client->net, reply);
715 if (expread(request.from, buf + sizeof(struct nbd_reply), len, client)) {
716 DEBUG("Read failed: %m");
717 ERROR(client, reply);
722 memcpy(buf, &reply, sizeof(struct nbd_reply));
723 writeit(client->net, buf, len + sizeof(struct nbd_reply));
730 * Split a single exportfile into multiple ones, if that was asked.
731 * @return 0 on success, -1 on failure
732 * @param client information on the client which we want to split
734 int splitexport(CLIENT* client) {
737 for (i=0; i<client->exportsize; i+=client->server->hunksize) {
740 if(client->server->flags & F_MULTIFILE) {
741 tmpname=g_strdup_printf("%s.%d", client->exportname,
742 (int)(i/client->server->hunksize));
744 tmpname=g_strdup(client->exportname);
746 DEBUG2( "Opening %s\n", tmpname );
747 if ((client->export[ i/ client->server->hunksize ] =
748 open(tmpname, (client->server->flags &
749 F_READONLY) ? O_RDONLY
751 /* Read WRITE ACCESS was requested by media is only read only */
752 client->server->flags |= F_AUTOREADONLY;
753 client->server->flags |= F_READONLY;
754 if ((client->export[i/client->server->hunksize] =
755 open(tmpname, O_RDONLY)) == -1)
756 err("Could not open exported file: %m");
762 int copyonwrite_prepare(CLIENT* client)
765 if ((client->difffilename = malloc(1024))==NULL)
766 err("Failed to allocate string for diff file name");
767 snprintf(client->difffilename, 1024, "%s-%s-%d.diff",client->exportname,client->clientname,
769 client->difffilename[1023]='\0';
770 msg3(LOG_INFO,"About to create map and diff file %s",client->difffilename) ;
771 client->difffile=open(client->difffilename,O_RDWR | O_CREAT | O_TRUNC,0600) ;
772 if (client->difffile<0) err("Could not create diff file (%m)") ;
773 if ((client->difmap=calloc(client->exportsize/DIFFPAGESIZE,sizeof(u32)))==NULL)
774 err("Could not allocate memory") ;
775 for (i=0;i<client->exportsize/DIFFPAGESIZE;i++) client->difmap[i]=(u32)-1 ;
781 * Serve a connection.
783 * @todo allow for multithreading, perhaps use libevent. Not just yet, though;
784 * follow the road map.
786 * @param net A network socket connected to an nbd client
788 void serveconnection(CLIENT *client) {
791 if (!client->server->expected_size) {
792 client->exportsize = size_autodetect(client->export[0]);
794 /* Perhaps we should check first. Not now. */
795 client->exportsize = client->server->expected_size;
797 if (client->exportsize > OFFT_MAX) {
798 /* uhm, well... In a parallel universe, this *might* be
800 err("Size of exported file is too big\n");
803 msg3(LOG_INFO, "size of exported file/device is %Lu", (unsigned long long)client->exportsize);
806 if (client->server->flags & F_COPYONWRITE) {
807 copyonwrite_prepare(client);
810 setmysockopt(client->net);
816 * Find the name of the file we have to serve. This will use g_strdup_printf
817 * to put the IP address of the client inside a filename containing
818 * "%s". That name is then written to client->exportname.
820 * @param net A socket connected to an nbd client
821 * @param client information about the client. The IP address in human-readable
822 * format will be written to a new char* buffer, the address of which will be
823 * stored in client->clientname.
825 void set_peername(int net, CLIENT *client) {
826 struct sockaddr_in addrin;
827 int addrinlen = sizeof( addrin );
830 if (getpeername(net, (struct sockaddr *) &addrin, (socklen_t *)&addrinlen) < 0)
831 err("getsockname failed: %m");
832 peername = inet_ntoa(addrin.sin_addr);
833 client->exportname=g_strdup_printf(client->server->exportname, peername);
835 msg4(LOG_INFO, "connect from %s, assigned file is %s",
836 peername, client->exportname);
837 client->clientname=g_strdup(peername);
842 * @param data a pointer to pid_t which should be freed
844 void destroy_pid_t(gpointer data) {
849 * Go daemon (unless we specified at compile time that we didn't want this)
850 * @param serve the first server of our configuration. If its port is zero,
851 * then do not daemonize, because we're doing inetd then.
853 #if !defined(NODAEMON) && !defined(NOFORK)
854 void daemonize(SERVER* serve) {
861 snprintf(pidfname, sizeof(char)*255, "/var/run/nbd-server.%d.pid", serve->port);
862 pidf=fopen(pidfname, "w");
864 fprintf(pidf,"%d", (int)getpid());
868 fprintf(stderr, "Not fatal; continuing");
873 #define daemonize(serve)
874 #endif /* !defined(NODAEMON) && !defined(NOFORK) */
877 * Connect a server's socket.
879 * @todo modularize this giant beast. Preferably with a chainsaw. Also,
880 * it has no business starting mainloop(), through serveconnection(); it
881 * should connect, and be done with it.
883 * @param serve the server we want to connect.
885 void setup_serve(SERVER* serve) {
886 struct sockaddr_in addrin;
888 int addrinlen = sizeof(addrin);
895 if ((serve->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
898 /* lose the pesky "Address already in use" error message */
899 if (setsockopt(serve->socket,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int)) == -1) {
900 err("setsockopt SO_REUSEADDR");
902 if (setsockopt(serve->socket,SOL_SOCKET,SO_KEEPALIVE,&yes,sizeof(int)) == -1) {
903 err("setsockopt SO_KEEPALIVE");
906 DEBUG("Waiting for connections... bind, ");
907 addrin.sin_family = AF_INET;
908 addrin.sin_port = htons(serve->port);
909 addrin.sin_addr.s_addr = 0;
910 if (bind(serve->socket, (struct sockaddr *) &addrin, addrinlen) < 0)
913 if (listen(serve->socket, 1) < 0)
915 sa.sa_handler = sigchld_handler;
916 sigemptyset(&sa.sa_mask);
917 sa.sa_flags = SA_RESTART;
918 if(sigaction(SIGCHLD, &sa, NULL) == -1)
919 err("sigaction: %m");
920 sa.sa_handler = sigterm_handler;
921 sigemptyset(&sa.sa_mask);
922 sa.sa_flags = SA_RESTART;
923 if(sigaction(SIGTERM, &sa, NULL) == -1)
924 err("sigaction: %m");
925 children=g_hash_table_new_full(g_int_hash, g_int_equal, NULL, destroy_pid_t);
929 * Loop through the available servers, and serve them.
931 * Actually, right now we only handle one server. Will change that for
934 int serveloop(SERVER* serve) {
935 struct sockaddr_in addrin;
936 socklen_t addrinlen=sizeof(addrin);
943 if ((net = accept(serve->socket, (struct sockaddr *) &addrin, &addrinlen)) < 0)
946 client = g_malloc(sizeof(CLIENT));
947 client->server=serve;
948 client->exportsize=OFFT_MAX;
950 set_peername(net, client);
951 if (!authorized_client(client)) {
952 msg2(LOG_INFO,"Unauthorized client") ;
956 msg2(LOG_INFO,"Authorized client") ;
957 pid=g_malloc(sizeof(pid_t));
959 if ((*pid=fork())<0) {
960 msg3(LOG_INFO,"Could not fork (%s)",strerror(errno)) ;
964 if (*pid>0) { /* parent */
966 g_hash_table_insert(children, pid, pid);
970 g_hash_table_destroy(children);
971 close(serve->socket) ;
973 msg2(LOG_INFO,"Starting to serve") ;
974 serveconnection(client);
979 * Main entry point...
981 int main(int argc, char *argv[]) {
985 if (sizeof( struct nbd_request )!=28) {
986 fprintf(stderr,"Bad size of structure. Alignment problems?\n");
991 serve=cmdline(argc, argv);
992 servers=g_array_new(TRUE, FALSE, sizeof(SERVER*));
994 if (!(serve->port)) {
997 /* You really should define ISSERVER if you're going to use
998 * inetd mode, but if you don't, closing stdout and stderr
999 * (which inetd had connected to the client socket) will let it
1003 open("/dev/null", O_WRONLY);
1004 open("/dev/null", O_WRONLY);
1006 client=g_malloc(sizeof(CLIENT));
1007 client->server=serve;
1009 client->exportsize=OFFT_MAX;
1010 set_peername(0,client);
1011 serveconnection(client);