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 /** Default position of the config file */
93 #define SYSCONFDIR "/etc"
95 #define CFILE SYSCONFDIR "/nbd-server/config"
97 /** Where our config file actually is */
98 gchar* config_file_pos;
100 /** how much space for child PIDs we have by default. Dynamically
101 allocated, and will be realloc()ed if out of space, so this should
102 probably be fair for most situations. */
103 #define DEFAULT_CHILD_ARRAY 256
105 /** Logging macros, now nothing goes to syslog unless you say ISSERVER */
107 #define msg2(a,b) syslog(a,b)
108 #define msg3(a,b,c) syslog(a,b,c)
109 #define msg4(a,b,c,d) syslog(a,b,c,d)
111 #define msg2(a,b) g_message(b)
112 #define msg3(a,b,c) g_message(b,c)
113 #define msg4(a,b,c,d) g_message(b,c,d)
116 /* Debugging macros */
119 #define DEBUG( a ) printf( a )
120 #define DEBUG2( a,b ) printf( a,b )
121 #define DEBUG3( a,b,c ) printf( a,b,c )
124 #define DEBUG2( a,b )
125 #define DEBUG3( a,b,c )
127 #ifndef PACKAGE_VERSION
128 #define PACKAGE_VERSION ""
131 * The highest value a variable of type off_t can reach.
133 /* This is starting to get ugly. If someone knows a better way to find
134 * the maximum value of a signed type *without* relying on overflow
135 * (doing so breaks on 64bit architectures), that would be nice.
137 * Actually, do we need this at all? Can't we just say '0 is autodetect', and
138 * live with it? Or better yet, use an extra flag, or so?
139 * Answer: yes, we need it, as the hunksize is defined to this when the
140 * multiple file thingy isn't used.
142 #define OFFT_MAX (((((off_t)1)<<((sizeof(off_t)-1)*8))-1)<<7)+127
143 #define LINELEN 256 /**< Size of static buffer used to read the
144 authorization file (yuck) */
145 #define BUFSIZE (1024*1024) /**< Size of buffer that can hold requests */
146 #define GIGA (1*1024*1024*1024) /**< 1 Gigabyte. Used as hunksize when doing
147 the multiple file thingy. @todo: make this a
148 configuration option. */
149 #define DIFFPAGESIZE 4096 /**< diff file uses those chunks */
150 #define F_READONLY 1 /**< flag to tell us a file is readonly */
151 #define F_MULTIFILE 2 /**< flag to tell us a file is exported using -m */
152 #define F_COPYONWRITE 4 /**< flag to tell us a file is exported using
154 #define F_AUTOREADONLY 8 /**< flag to tell us a file is set to autoreadonly */
155 GHashTable *children;
156 char pidfname[256]; /**< name of our PID file */
157 char default_authname[] = "/etc/nbd_server.allow"; /**< default name of allow file */
160 * Variables associated with a server.
163 gchar* exportname; /**< (unprocessed) filename of the file we're exporting */
164 off_t hunksize; /**< size of a hunk of an exported file */
165 off_t expected_size; /**< size of the exported file as it was told to
166 us through configuration */
167 unsigned int port; /**< port we're exporting this file at */
168 char* authname; /**< filename of the authorization file */
169 int flags; /**< flags associated with this exported file */
170 unsigned int timeout;/**< how long a connection may be idle
172 int socket; /**< The socket of this server. */
176 * Variables associated with a client socket.
179 off_t exportsize; /**< size of the file we're exporting */
180 char *clientname; /**< peer */
181 char *exportname; /**< (processed) filename of the file we're exporting */
182 GArray *export; /**< array of filedescriptors of exported files;
183 only the first is actually used unless we're
184 doing the multiple file option */
185 int net; /**< The actual client socket */
186 SERVER *server; /**< The server this client is getting data from */
187 char* difffilename; /**< filename of the copy-on-write file, if any */
188 int difffile; /**< filedescriptor of copyonwrite file. @todo
189 shouldn't this be an array too? (cfr export) Or
190 make -m and -c mutually exclusive */
191 u32 difffilelen; /**< number of pages in difffile */
192 u32 *difmap; /**< see comment on the global difmap for this one */
196 * Type of configuration file values
199 PARAM_INT, /**< This parameter is an integer */
200 PARAM_STRING, /**< This parameter is a string */
201 PARAM_BOOL, /**< This parameter is a boolean */
204 * Configuration file values
207 gchar *paramname; /**< Name of the parameter, as it appears in
209 gboolean required; /**< Whether this is a required (as opposed to
210 optional) parameter */
211 PARAM_TYPE ptype; /**< Type of the parameter. */
212 gpointer target; /**< Pointer to where the data of this
213 parameter should be written. If ptype is
214 PARAM_BOOL, the data is or'ed rather than
216 gint flagval; /**< Flag mask for this parameter in case ptype
221 * Check whether a client is allowed to connect. Works with an authorization
222 * file which contains one line per machine, no wildcards.
224 * @param opts The client who's trying to connect.
225 * @return 0 - authorization refused, 1 - OK
227 int authorized_client(CLIENT *opts) {
232 if ((f=fopen(opts->server->authname,"r"))==NULL) {
233 msg4(LOG_INFO,"Can't open authorization file %s (%s).",
234 opts->server->authname,strerror(errno)) ;
238 while (fgets(line,LINELEN,f)!=NULL) {
239 if (strncmp(line,opts->clientname,strlen(opts->clientname))==0) {
249 * Read data from a file descriptor into a buffer
251 * @param f a file descriptor
252 * @param buf a buffer
253 * @param len the number of bytes to be read
255 inline void readit(int f, void *buf, size_t len) {
259 if ((res = read(f, buf, len)) <= 0)
260 err("Read failed: %m");
267 * Write data from a buffer into a filedescriptor
269 * @param f a file descriptor
270 * @param buf a buffer containing data
271 * @param len the number of bytes to be written
273 inline void writeit(int f, void *buf, size_t len) {
277 if ((res = write(f, buf, len)) <= 0)
278 err("Send failed: %m");
285 * Print out a message about how to use nbd-server. Split out to a separate
286 * function so that we can call it from multiple places
289 printf("This is nbd-server version " VERSION "\n");
290 printf("Usage: port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-a timeout_sec]\n"
291 "\t-r|--read-only\t\tread only\n"
292 "\t-m|--multi-file\t\tmultiple file\n"
293 "\t-c|--copy-on-write\tcopy on write\n"
294 "\t-l|--authorize-file\tfile with list of hosts that are allowed to\n\t\t\t\tconnect.\n"
295 "\t-a|--idle-time\t\tmaximum idle seconds; server terminates when\n\t\t\t\tidle time exceeded\n\n"
296 "\tif port is set to 0, stdin is used (for running from inetd)\n"
297 "\tif file_to_export contains '%%s', it is substituted with the IP\n"
298 "\t\taddress of the machine trying to connect\n" );
299 printf("Using configuration file %s\n", CFILE);
303 * Parse the command line.
305 * @param argc the argc argument to main()
306 * @param argv the argv argument to main()
308 SERVER* cmdline(int argc, char *argv[]) {
312 struct option long_options[] = {
313 {"read-only", no_argument, NULL, 'r'},
314 {"multi-file", no_argument, NULL, 'm'},
315 {"copy-on-write", no_argument, NULL, 'c'},
316 {"authorize-file", required_argument, NULL, 'l'},
317 {"idle-time", required_argument, NULL, 'a'},
318 {"config-file", required_argument, NULL, 'C'},
329 serve=g_new0(SERVER, 1);
330 serve->hunksize=OFFT_MAX;
331 serve->authname = g_strdup(default_authname);
332 while((c=getopt_long(argc, argv, "-a:C:cl:mr", long_options, &i))>=0) {
335 /* non-option argument */
336 switch(nonspecial++) {
338 serve->port=strtol(optarg, NULL, 0);
341 serve->exportname = g_strdup(optarg);
342 if(serve->exportname[0] != '/') {
343 fprintf(stderr, "E: The to be exported file needs to be an absolute filename!\n");
348 last=strlen(optarg)-1;
350 if (suffix == 'k' || suffix == 'K' ||
351 suffix == 'm' || suffix == 'M')
353 es = (off_t)atol(optarg);
361 serve->expected_size = es;
366 serve->flags |= F_READONLY;
369 serve->flags |= F_MULTIFILE;
370 serve->hunksize = 1*GIGA;
373 serve->flags |=F_COPYONWRITE;
376 g_free(config_file_pos);
377 config_file_pos=g_strdup(optarg);
380 g_free(serve->authname);
381 serve->authname=g_strdup(optarg);
384 serve->timeout=strtol(optarg, NULL, 0);
392 /* What's left: the port to export, the name of the to be exported
393 * file, and, optionally, the size of the file, in that order. */
402 * Error codes for config file parsing
405 CFILE_NOTFOUND, /**< The configuration file is not found */
406 CFILE_MISSING_GENERIC, /**< The (required) group "generic" is missing */
407 CFILE_KEY_MISSING, /**< A (required) key is missing */
408 CFILE_VALUE_INVALID, /**< A value is syntactically invalid */
409 CFILE_PROGERR /**< Programmer error */
413 * Remove a SERVER from memory. Used from the hash table
415 void remove_server(gpointer s) {
419 g_free(server->exportname);
421 g_free(server->authname);
426 * Parse the config file.
428 * @param f the name of the config file
429 * @param e a GError. @see CFILE_ERRORS for what error values this function can
431 * @return a GHashTable of SERVER* pointers, with the port number as the hash
432 * key. If the config file is empty or does not exist, returns an empty
433 * GHashTable; if the config file contains an error, returns NULL, and
434 * e is set appropriately
436 GArray* parse_cfile(gchar* f, GError** e) {
439 { "exportname", TRUE, PARAM_STRING, NULL, 0 },
440 { "port", TRUE, PARAM_INT, NULL, 0 },
441 { "authfile", FALSE, PARAM_STRING, NULL, 0 },
442 { "timeout", FALSE, PARAM_INT, NULL, 0 },
443 { "filesize", FALSE, PARAM_INT, NULL, 0 },
444 { "readonly", FALSE, PARAM_BOOL, NULL, F_READONLY },
445 { "multifile", FALSE, PARAM_BOOL, NULL, F_MULTIFILE },
446 { "copyonwrite", FALSE, PARAM_BOOL, NULL, F_COPYONWRITE },
456 errdomain = g_quark_from_string("parse_cfile");
457 cfile = g_key_file_new();
458 retval = g_array_new(FALSE, TRUE, sizeof(SERVER));
459 if(!g_key_file_load_from_file(cfile, f, G_KEY_FILE_KEEP_COMMENTS |
460 G_KEY_FILE_KEEP_TRANSLATIONS, &err)) {
461 g_set_error(e, errdomain, CFILE_NOTFOUND, "Could not open config file.");
462 g_key_file_free(cfile);
465 if(strcmp(g_key_file_get_start_group(cfile), "generic")) {
466 g_set_error(e, errdomain, CFILE_MISSING_GENERIC, "Config file does not contain the [generic] group!");
467 g_key_file_free(cfile);
470 groups = g_key_file_get_groups(cfile, NULL);
471 for(i=0;groups[i];i++) {
472 p[0].target=&(s.exportname);
473 p[1].target=&(s.port);
474 p[2].target=&(s.authname);
475 p[3].target=&(s.timeout);
476 p[4].target=&(s.expected_size);
477 p[5].target=p[6].target=p[7].target=p[8].target=&(s.flags);
479 g_assert(p[j].target != NULL);
480 g_assert(p[j].ptype==PARAM_INT||p[j].ptype==PARAM_STRING||p[j].ptype==PARAM_BOOL);
483 *((gint*)p[j].target) = g_key_file_get_integer(cfile, groups[i], p[j].paramname, &err);
486 *((gchar**)p[j].target) = g_key_file_get_string(cfile, groups[i], p[j].paramname, &err);
489 value = g_key_file_get_boolean(cfile, groups[i], p[j].paramname, &err);
491 *((gint*)p[j].target) |= value;
496 if(err->code == G_KEY_FILE_ERROR_KEY_NOT_FOUND) {
498 g_set_error(e, errdomain, CFILE_KEY_MISSING, "Could not find required value %s in group %s: %s", p[j].paramname, groups[i], err->message);
499 g_array_free(retval, TRUE);
501 g_key_file_free(cfile);
507 g_set_error(e, errdomain, CFILE_VALUE_INVALID, "Could not parse %s in group %s: %s", p[j].paramname, groups[i], err->message);
508 g_array_free(retval, TRUE);
510 g_key_file_free(cfile);
515 g_array_append_val(retval, s);
521 * Signal handler for SIGCHLD
522 * @param s the signal we're handling (must be SIGCHLD, or something
525 void sigchld_handler(int s) {
530 while((pid=wait(status)) > 0) {
531 if(WIFEXITED(status)) {
532 msg3(LOG_INFO, "Child exited with %d", WEXITSTATUS(status));
534 i=g_hash_table_lookup(children, &pid);
536 msg3(LOG_INFO, "SIGCHLD received for an unknown child with PID %ld", (long)pid);
538 DEBUG2("Removing %d from the list of children", pid);
539 g_hash_table_remove(children, &pid);
545 * Kill a child. Called from sigterm_handler::g_hash_table_foreach.
548 * @param value the value corresponding to the above key
549 * @param user_data a pointer which we always set to 1, so that we know what
552 void killchild(gpointer key, gpointer value, gpointer user_data) {
554 int *parent=user_data;
561 * Handle SIGTERM and dispatch it to our children
562 * @param s the signal we're handling (must be SIGTERM, or something
563 * is severely wrong).
565 void sigterm_handler(int s) {
568 g_hash_table_foreach(children, killchild, &parent);
578 * Detect the size of a file.
580 * @param export An open filedescriptor
581 * @return the size of the file, or OFFT_MAX if detection was
584 off_t size_autodetect(int export) {
587 struct stat stat_buf;
590 #ifdef HAVE_SYS_MOUNT_H
591 #ifdef HAVE_SYS_IOCTL_H
593 DEBUG("looking for export size with ioctl BLKGETSIZE\n");
594 if (!ioctl(export, BLKGETSIZE, &es32) && es32) {
595 es = (off_t)es32 * (off_t)512;
598 #endif /* BLKGETSIZE */
599 #endif /* HAVE_SYS_IOCTL_H */
600 #endif /* HAVE_SYS_MOUNT_H */
602 DEBUG("looking for export size with fstat\n");
603 stat_buf.st_size = 0;
604 error = fstat(export, &stat_buf);
606 if(stat_buf.st_size > 0)
607 return (off_t)stat_buf.st_size;
609 err("fstat failed: %m");
612 DEBUG("looking for export size with lseek SEEK_END\n");
613 es = lseek(export, (off_t)0, SEEK_END);
614 if (es > ((off_t)0)) {
617 DEBUG2("lseek failed: %d", errno==EBADF?1:(errno==ESPIPE?2:(errno==EINVAL?3:4)));
620 err("Could not find size of exported block device: %m");
625 * seek to a position in a file, with error handling.
626 * @param handle a filedescriptor
627 * @param a position to seek to
628 * @todo get rid of this; lastpoint is a global variable right now, but it
629 * shouldn't be. If we pass it on as a parameter, that makes things a *lot*
632 void myseek(int handle,off_t a) {
633 if (lseek(handle, a, SEEK_SET) < 0) {
634 err("Can not seek locally!\n");
639 * Write an amount of bytes at a given offset to the right file. This
640 * abstracts the write-side of the multiple file option.
642 * @param a The offset where the write should start
643 * @param buf The buffer to write from
644 * @param len The length of buf
645 * @param client The client we're serving for
646 * @return The number of bytes actually written, or -1 in case of an error
648 int rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client) {
651 myseek(g_array_index(client->export, int, (int)(a/client->server->hunksize)), a%client->server->hunksize);
653 res = write(g_array_index(client->export, int, (int)((off_t)a/(off_t)(client->server->hunksize))), buf, len);
654 return (res < 0 || (size_t)res != len);
658 * Read an amount of bytes at a given offset from the right file. This
659 * abstracts the read-side of the multiple files option.
661 * @param a The offset where the read should start
662 * @param buf A buffer to read into
663 * @param len The size of buf
664 * @param client The client we're serving for
665 * @return The number of bytes actually read, or -1 in case of an
668 int rawexpread(off_t a, char *buf, size_t len, CLIENT *client) {
671 myseek(g_array_index(client->export,int,(int)a/client->server->hunksize),
672 a%client->server->hunksize);
673 res = read(g_array_index(client->export,int,(int)a/client->server->hunksize), buf, len);
674 return (res < 0 || (size_t)res != len);
678 * Read an amount of bytes at a given offset from the right file. This
679 * abstracts the read-side of the copyonwrite stuff, and calls
680 * rawexpread() with the right parameters to do the actual work.
681 * @param a The offset where the read should start
682 * @param buf A buffer to read into
683 * @param len The size of buf
684 * @param client The client we're going to read for
685 * @return The number of bytes actually read, or -1 in case of an error
687 int expread(off_t a, char *buf, size_t len, CLIENT *client) {
689 off_t mapcnt, mapl, maph, pagestart;
691 if (!(client->server->flags & F_COPYONWRITE))
692 return rawexpread(a, buf, len, client);
693 DEBUG3("Asked to read %d bytes at %Lu.\n", len, (unsigned long long)a);
695 mapl=a/DIFFPAGESIZE; maph=(a+len-1)/DIFFPAGESIZE;
697 for (mapcnt=mapl;mapcnt<=maph;mapcnt++) {
698 pagestart=mapcnt*DIFFPAGESIZE;
700 rdlen=(0<DIFFPAGESIZE-offset && len<(size_t)(DIFFPAGESIZE-offset)) ?
701 len : (size_t)DIFFPAGESIZE-offset;
702 if (client->difmap[mapcnt]!=(u32)(-1)) { /* the block is already there */
703 DEBUG3("Page %Lu is at %lu\n", (unsigned long long)mapcnt,
704 (unsigned long)(client->difmap[mapcnt]));
705 myseek(client->difffile, client->difmap[mapcnt]*DIFFPAGESIZE+offset);
706 if (read(client->difffile, buf, rdlen) != rdlen) return -1;
707 } else { /* the block is not there */
708 DEBUG2("Page %Lu is not here, we read the original one\n",
709 (unsigned long long)mapcnt);
710 if(rawexpread(a, buf, rdlen, client)) return -1;
712 len-=rdlen; a+=rdlen; buf+=rdlen;
718 * Write an amount of bytes at a given offset to the right file. This
719 * abstracts the write-side of the copyonwrite option, and calls
720 * rawexpwrite() with the right parameters to do the actual work.
722 * @param a The offset where the write should start
723 * @param buf The buffer to write from
724 * @param len The length of buf
725 * @param client The client we're going to write for.
726 * @return The number of bytes actually written, or -1 in case of an error
728 int expwrite(off_t a, char *buf, size_t len, CLIENT *client) {
729 char pagebuf[DIFFPAGESIZE];
730 off_t mapcnt,mapl,maph;
735 if (!(client->server->flags & F_COPYONWRITE))
736 return(rawexpwrite(a,buf,len, client));
737 DEBUG3("Asked to write %d bytes at %Lu.\n", len, (unsigned long long)a);
739 mapl=a/DIFFPAGESIZE ; maph=(a+len-1)/DIFFPAGESIZE ;
741 for (mapcnt=mapl;mapcnt<=maph;mapcnt++) {
742 pagestart=mapcnt*DIFFPAGESIZE ;
744 wrlen=(0<DIFFPAGESIZE-offset && len<(size_t)(DIFFPAGESIZE-offset)) ?
745 len : (size_t)DIFFPAGESIZE-offset;
747 if (client->difmap[mapcnt]!=(u32)(-1)) { /* the block is already there */
748 DEBUG3("Page %Lu is at %lu\n", (unsigned long long)mapcnt,
749 (unsigned long)(client->difmap[mapcnt])) ;
750 myseek(client->difffile,
751 client->difmap[mapcnt]*DIFFPAGESIZE+offset);
752 if (write(client->difffile, buf, wrlen) != wrlen) return -1 ;
753 } else { /* the block is not there */
754 myseek(client->difffile,client->difffilelen*DIFFPAGESIZE) ;
755 client->difmap[mapcnt]=client->difffilelen++ ;
756 DEBUG3("Page %Lu is not here, we put it at %lu\n",
757 (unsigned long long)mapcnt,
758 (unsigned long)(client->difmap[mapcnt]));
760 if (rdlen+pagestart%(client->server->hunksize) >
761 (client->server->hunksize))
762 rdlen=client->server->hunksize -
763 (pagestart%client->server->hunksize);
764 if (rawexpread(pagestart, pagebuf, rdlen, client))
766 memcpy(pagebuf+offset,buf,wrlen) ;
767 if (write(client->difffile, pagebuf, DIFFPAGESIZE) !=
771 len-=wrlen ; a+=wrlen ; buf+=wrlen ;
777 * Do the initial negotiation.
779 * @param client The client we're negotiating with.
781 void negotiate(CLIENT *client) {
785 memset(zeros, 0, 290);
786 if (write(client->net, INIT_PASSWD, 8) < 0)
787 err("Negotiation failed: %m");
788 cliserv_magic = htonll(cliserv_magic);
789 if (write(client->net, &cliserv_magic, sizeof(cliserv_magic)) < 0)
790 err("Negotiation failed: %m");
791 size_host = htonll((u64)(client->exportsize));
792 if (write(client->net, &size_host, 8) < 0)
793 err("Negotiation failed: %m");
794 if (write(client->net, zeros, 128) < 0)
795 err("Negotiation failed: %m");
798 /** sending macro. */
799 #define SEND(net,reply) writeit( net, &reply, sizeof( reply ));
801 #define ERROR(client,reply) { reply.error = htonl(-1); SEND(client->net,reply); reply.error = 0; }
803 * Serve a file to a single client.
805 * @todo This beast needs to be split up in many tiny little manageable
806 * pieces. Preferably with a chainsaw.
808 * @param client The client we're going to serve to.
811 int mainloop(CLIENT *client) {
812 struct nbd_request request;
813 struct nbd_reply reply;
819 DEBUG("Entering request loop!\n");
820 reply.magic = htonl(NBD_REPLY_MAGIC);
829 if (client->server->timeout)
830 alarm(client->server->timeout);
831 readit(client->net, &request, sizeof(request));
832 request.from = ntohll(request.from);
833 request.type = ntohl(request.type);
835 if (request.type==NBD_CMD_DISC) {
836 msg2(LOG_INFO, "Disconnect request received.");
837 if (client->difmap) g_free(client->difmap) ;
838 if (client->difffile>=0) {
839 close(client->difffile);
840 unlink(client->difffilename);
841 free(client->difffilename);
847 len = ntohl(request.len);
849 if (request.magic != htonl(NBD_REQUEST_MAGIC))
850 err("Not enough magic.");
851 if (len > BUFSIZE + sizeof(struct nbd_reply))
852 err("Request too big!");
854 printf("%s from %Lu (%Lu) len %d, ", request.type ? "WRITE" :
855 "READ", (unsigned long long)request.from,
856 (unsigned long long)request.from / 512, len);
858 memcpy(reply.handle, request.handle, sizeof(reply.handle));
859 if ((request.from + len) > (OFFT_MAX)) {
860 DEBUG("[Number too large!]");
861 ERROR(client, reply);
865 if (((ssize_t)((off_t)request.from + len) > client->exportsize) ||
866 ((client->server->flags & F_READONLY) && request.type)) {
868 ERROR(client, reply);
872 if (request.type==NBD_CMD_WRITE) {
873 DEBUG("wr: net->buf, ");
874 readit(client->net, buf, len);
876 if ((client->server->flags & F_AUTOREADONLY) ||
877 expwrite(request.from, buf, len,
879 DEBUG("Write failed: %m" );
880 ERROR(client, reply);
883 SEND(client->net, reply);
890 if (expread(request.from, buf + sizeof(struct nbd_reply), len, client)) {
891 DEBUG("Read failed: %m");
892 ERROR(client, reply);
897 memcpy(buf, &reply, sizeof(struct nbd_reply));
898 writeit(client->net, buf, len + sizeof(struct nbd_reply));
905 * Split a single exportfile into multiple ones, if that was asked.
906 * @return 0 on success, -1 on failure
907 * @param client information on the client which we want to split
909 int splitexport(CLIENT* client) {
913 client->export = g_array_new(TRUE, TRUE, sizeof(int));
914 for (i=0; i<client->exportsize; i+=client->server->hunksize) {
917 if(client->server->flags & F_MULTIFILE) {
918 tmpname=g_strdup_printf("%s.%d", client->exportname,
919 (int)(i/client->server->hunksize));
921 tmpname=g_strdup(client->exportname);
923 DEBUG2( "Opening %s\n", tmpname );
924 if((fhandle = open(tmpname, (client->server->flags & F_READONLY) ? O_RDONLY : O_RDWR)) == -1) {
925 /* Read WRITE ACCESS was requested by media is only read only */
926 client->server->flags |= F_AUTOREADONLY;
927 client->server->flags |= F_READONLY;
928 if((fhandle = open(tmpname, O_RDONLY)) == -1)
929 err("Could not open exported file: %m");
931 g_array_insert_val(client->export,i/client->server->hunksize,fhandle);
936 int copyonwrite_prepare(CLIENT* client)
939 if ((client->difffilename = malloc(1024))==NULL)
940 err("Failed to allocate string for diff file name");
941 snprintf(client->difffilename, 1024, "%s-%s-%d.diff",client->exportname,client->clientname,
943 client->difffilename[1023]='\0';
944 msg3(LOG_INFO,"About to create map and diff file %s",client->difffilename) ;
945 client->difffile=open(client->difffilename,O_RDWR | O_CREAT | O_TRUNC,0600) ;
946 if (client->difffile<0) err("Could not create diff file (%m)") ;
947 if ((client->difmap=calloc(client->exportsize/DIFFPAGESIZE,sizeof(u32)))==NULL)
948 err("Could not allocate memory") ;
949 for (i=0;i<client->exportsize/DIFFPAGESIZE;i++) client->difmap[i]=(u32)-1 ;
955 * Serve a connection.
957 * @todo allow for multithreading, perhaps use libevent. Not just yet, though;
958 * follow the road map.
960 * @param client a connected client
962 void serveconnection(CLIENT *client) {
965 if (!client->server->expected_size) {
966 client->exportsize = size_autodetect(g_array_index(client->export,int,0));
968 /* Perhaps we should check first. Not now. */
969 client->exportsize = client->server->expected_size;
971 if (client->exportsize > OFFT_MAX) {
972 /* uhm, well... In a parallel universe, this *might* be
974 err("Size of exported file is too big\n");
977 msg3(LOG_INFO, "size of exported file/device is %Lu", (unsigned long long)client->exportsize);
980 if (client->server->flags & F_COPYONWRITE) {
981 copyonwrite_prepare(client);
984 setmysockopt(client->net);
990 * Find the name of the file we have to serve. This will use g_strdup_printf
991 * to put the IP address of the client inside a filename containing
992 * "%s". That name is then written to client->exportname.
994 * @param net A socket connected to an nbd client
995 * @param client information about the client. The IP address in human-readable
996 * format will be written to a new char* buffer, the address of which will be
997 * stored in client->clientname.
999 void set_peername(int net, CLIENT *client) {
1000 struct sockaddr_in addrin;
1001 int addrinlen = sizeof( addrin );
1004 if (getpeername(net, (struct sockaddr *) &addrin, (socklen_t *)&addrinlen) < 0)
1005 err("getsockname failed: %m");
1006 peername = inet_ntoa(addrin.sin_addr);
1007 client->exportname=g_strdup_printf(client->server->exportname, peername);
1009 msg4(LOG_INFO, "connect from %s, assigned file is %s",
1010 peername, client->exportname);
1011 client->clientname=g_strdup(peername);
1016 * @param data a pointer to pid_t which should be freed
1018 void destroy_pid_t(gpointer data) {
1023 * Go daemon (unless we specified at compile time that we didn't want this)
1024 * @param serve the first server of our configuration. If its port is zero,
1025 * then do not daemonize, because we're doing inetd then. This parameter
1026 * is only used to create a PID file of the form
1027 * /var/run/nbd-server.<port>.pid; it's not modified in any way.
1029 #if !defined(NODAEMON) && !defined(NOFORK)
1030 void daemonize(SERVER* serve) {
1037 snprintf(pidfname, sizeof(char)*255, "/var/run/nbd-server.%d.pid", serve->port);
1039 strncpy(pidfname, "/var/run/nbd-server.pid", sizeof(char)*255);
1041 pidf=fopen(pidfname, "w");
1043 fprintf(pidf,"%d\n", (int)getpid());
1047 fprintf(stderr, "Not fatal; continuing");
1051 #define daemonize(serve)
1052 #endif /* !defined(NODAEMON) && !defined(NOFORK) */
1055 * Connect a server's socket.
1057 * @param serve the server we want to connect.
1059 void setup_serve(SERVER *serve) {
1060 struct sockaddr_in addrin;
1061 struct sigaction sa;
1062 int addrinlen = sizeof(addrin);
1068 if ((serve->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
1071 /* lose the pesky "Address already in use" error message */
1072 if (setsockopt(serve->socket,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int)) == -1) {
1073 err("setsockopt SO_REUSEADDR");
1075 if (setsockopt(serve->socket,SOL_SOCKET,SO_KEEPALIVE,&yes,sizeof(int)) == -1) {
1076 err("setsockopt SO_KEEPALIVE");
1079 DEBUG("Waiting for connections... bind, ");
1080 addrin.sin_family = AF_INET;
1081 addrin.sin_port = htons(serve->port);
1082 addrin.sin_addr.s_addr = 0;
1083 if (bind(serve->socket, (struct sockaddr *) &addrin, addrinlen) < 0)
1086 if (listen(serve->socket, 1) < 0)
1088 sa.sa_handler = sigchld_handler;
1089 sigemptyset(&sa.sa_mask);
1090 sa.sa_flags = SA_RESTART;
1091 if(sigaction(SIGCHLD, &sa, NULL) == -1)
1092 err("sigaction: %m");
1093 sa.sa_handler = sigterm_handler;
1094 sigemptyset(&sa.sa_mask);
1095 sa.sa_flags = SA_RESTART;
1096 if(sigaction(SIGTERM, &sa, NULL) == -1)
1097 err("sigaction: %m");
1098 children=g_hash_table_new_full(g_int_hash, g_int_equal, NULL, destroy_pid_t);
1102 * Connect our servers.
1104 void setup_servers(GArray* servers) {
1107 for(i=0;i<servers->len;i++) {
1108 setup_serve(&(g_array_index(servers, SERVER, i)));
1113 * Loop through the available servers, and serve them.
1115 int serveloop(GArray* servers) {
1116 struct sockaddr_in addrin;
1117 socklen_t addrinlen=sizeof(addrin);
1124 * Set up the master fd_set. The set of descriptors we need
1125 * to select() for never changes anyway and it buys us a *lot*
1126 * of time to only build this once. However, if we ever choose
1127 * to not fork() for clients anymore, we may have to revisit
1132 for(i=0;i<servers->len;i++) {
1133 sock=(g_array_index(servers, SERVER, i)).socket;
1134 FD_SET(sock, &mset);
1135 max=sock>max?sock:max;
1142 memcpy(&rset, &mset, sizeof(fd_set));
1145 if(select(max+1, &rset, NULL, NULL, &tv)>0) {
1147 for(i=0;i<servers->len;i++) {
1148 serve=&(g_array_index(servers, SERVER, i));
1149 if(FD_ISSET(serve->socket, &rset)) {
1150 if ((net=accept(serve->socket, (struct sockaddr *) &addrin, &addrinlen)) < 0)
1153 client = g_malloc(sizeof(CLIENT));
1154 client->server=serve;
1155 client->exportsize=OFFT_MAX;
1157 set_peername(net, client);
1158 if (!authorized_client(client)) {
1159 msg2(LOG_INFO,"Unauthorized client") ;
1163 msg2(LOG_INFO,"Authorized client") ;
1164 pid=g_malloc(sizeof(pid_t));
1166 if ((*pid=fork())<0) {
1167 msg3(LOG_INFO,"Could not fork (%s)",strerror(errno)) ;
1171 if (*pid>0) { /* parent */
1173 g_hash_table_insert(children, pid, pid);
1177 g_hash_table_destroy(children);
1178 for(i=0;i<servers->len,serve=&(g_array_index(servers, SERVER, i));i++) {
1179 close(serve->socket);
1181 /* FALSE does not free the
1182 actual data. This is required,
1183 because the client has a
1184 direct reference into that
1185 data, and otherwise we get a
1187 g_array_free(servers, FALSE);
1189 msg2(LOG_INFO,"Starting to serve");
1190 serveconnection(client);
1198 * Main entry point...
1200 int main(int argc, char *argv[]) {
1205 if (sizeof( struct nbd_request )!=28) {
1206 fprintf(stderr,"Bad size of structure. Alignment problems?\n");
1211 config_file_pos = g_strdup(CFILE);
1212 serve=cmdline(argc, argv);
1213 servers = parse_cfile(config_file_pos, &err);
1215 g_critical("Could not parse command file: %s", err->message);
1218 g_array_append_val(servers, *serve);
1222 /* We don't support this at this time */
1224 if (!(serve->port)) {
1227 /* You really should define ISSERVER if you're going to use
1228 * inetd mode, but if you don't, closing stdout and stderr
1229 * (which inetd had connected to the client socket) will let it
1233 open("/dev/null", O_WRONLY);
1234 open("/dev/null", O_WRONLY);
1236 client=g_malloc(sizeof(CLIENT));
1237 client->server=serve;
1239 client->exportsize=OFFT_MAX;
1240 set_peername(0,client);
1241 serveconnection(client);
1245 if((!serve) && (!servers)) {
1246 g_message("Nothing to do! Bye!");
1250 setup_servers(servers);