/*
* Network Block Device - server
*
* Copyright 1996-1998 Pavel Machek, distribute under GPL
* <pavel@atrey.karlin.mff.cuni.cz>
* Copyright 2001-2004 Wouter Verhelst <wouter@debian.org>
* Copyright 2002 Anton Altaparmakov <aia21@cam.ac.uk>
*
* Version 1.0 - hopefully 64-bit-clean
* Version 1.1 - merging enhancements from Josh Parsons, <josh@coombs.anu.edu.au>
* Version 1.2 - autodetect size of block devices, thanx to Peter T. Breuer" <ptb@it.uc3m.es>
* Version 1.5 - can compile on Unix systems that don't have 64 bit integer
* type, or don't have 64 bit file offsets by defining FS_32BIT
* in compile options for nbd-server *only*. This can be done
* with make FSCHOICE=-DFS_32BIT nbd-server. (I don't have the
* original autoconf input file, or I would make it a configure
* option.) Ken Yap <ken@nlc.net.au>.
* Version 1.6 - fix autodetection of block device size and really make 64 bit
* clean on 32 bit machines. Anton Altaparmakov <aia21@cam.ac.uk>
* Version 2.0 - Version synchronised with client
* Version 2.1 - Reap zombie client processes when they exit. Removed
* (uncommented) the _IO magic, it's no longer necessary. Wouter
* Verhelst <wouter@debian.org>
* Version 2.2 - Auto switch to read-only mode (usefull for floppies).
* Version 2.3 - Fixed code so that Large File Support works. This
* removes the FS_32BIT compile-time directive; define
* _FILE_OFFSET_BITS=64 and _LARGEFILE_SOURCE if you used to be
* using FS_32BIT. This will allow you to use files >2GB instead of
* having to use the -m option. Wouter Verhelst <wouter@debian.org>
* Version 2.4 - Added code to keep track of children, so that we can
* properly kill them from initscripts. Add a call to daemon(),
* so that processes don't think they have to wait for us, which is
* interesting for initscripts as well. Wouter Verhelst
* <wouter@debian.org>
* Version 2.5 - Bugfix release: forgot to reset child_arraysize to
* zero after fork()ing, resulting in nbd-server going berserk
* when it receives a signal with at least one child open. Wouter
* Verhelst <wouter@debian.org>
* 10/10/2003 - Added socket option SO_KEEPALIVE (sf.net bug 819235);
* rectified type of mainloop::size_host (sf.net bugs 814435 and
* 817385); close the PID file after writing to it, so that the
* daemon can actually be found. Wouter Verhelst
* <wouter@debian.org>
* 10/10/2003 - Size of the data "size_host" was wrong and so was not
* correctly put in network endianness. Many types were corrected
* (size_t and off_t instead of int). <vspaceg@sourceforge.net>
* Version 2.6 - Some code cleanup.
* Version 2.7 - Better build system.
* 11/02/2004 - Doxygenified the source, modularized it a bit. Needs a
* lot more work, but this is a start. Wouter Verhelst
* <wouter@debian.org>
*/
/* Includes LFS defines, which defines behaviours of some of the following
* headers, so must come before those */
#include "lfs.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/wait.h> /* wait */
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#include <sys/param.h>
#ifdef HAVE_SYS_MOUNT_H
#include <sys/mount.h> /* For BLKGETSIZE */
#endif
#include <signal.h> /* sigaction */
#include <netinet/tcp.h>
#include <netinet/in.h> /* sockaddr_in, htons, in_addr */
#include <netdb.h> /* hostent, gethostby*, getservby* */
#include <syslog.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <arpa/inet.h>
#include <strings.h>
#include <dirent.h>
#include <unistd.h>
#include <getopt.h>
#include <glib.h>
/* used in cliserv.h, so must come first */
#define MY_NAME "nbd_server"
#include "cliserv.h"
/** how much space for child PIDs we have by default. Dynamically
allocated, and will be realloc()ed if out of space, so this should
probably be fair for most situations. */
#define DEFAULT_CHILD_ARRAY 256
/** Logging macros, now nothing goes to syslog unless you say ISSERVER */
#ifdef ISSERVER
#define msg2(a,b) syslog(a,b)
#define msg3(a,b,c) syslog(a,b,c)
#define msg4(a,b,c,d) syslog(a,b,c,d)
#else
#define msg2(a,b) g_message(b)
#define msg3(a,b,c) g_message(b,c)
#define msg4(a,b,c,d) g_message(b,c,d)
#endif
/* Debugging macros */
//#define DODBG
#ifdef DODBG
#define DEBUG( a ) printf( a )
#define DEBUG2( a,b ) printf( a,b )
#define DEBUG3( a,b,c ) printf( a,b,c )
#else
#define DEBUG( a )
#define DEBUG2( a,b )
#define DEBUG3( a,b,c )
#endif
#ifndef PACKAGE_VERSION
#define PACKAGE_VERSION ""
#endif
/**
* The highest value a variable of type off_t can reach.
**/
/* This is starting to get ugly. If someone knows a better way to find
* the maximum value of a signed type *without* relying on overflow
* (doing so breaks on 64bit architectures), that would be nice.
*
* Actually, do we need this at all? Can't we just say '0 is autodetect', and
* live with it? Or better yet, use an extra flag, or so?
* Answer: yes, we need it, as the hunksize is defined to this when the
* multiple file thingy isn't used.
*/
#define OFFT_MAX (((((off_t)1)<<((sizeof(off_t)-1)*8))-1)<<7)+127
#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 GIGA (1*1024*1024*1024) /**< 1 Gigabyte. Used as hunksize when doing
the multiple file thingy. @todo: make this a
configuration option. */
#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 */
#define F_COPYONWRITE 4 /**< flag to tell us a file is exported using
copyonwrite */
#define F_AUTOREADONLY 8 /**< flag to tell us a file is set to autoreadonly */
GHashTable *children;
char pidfname[256]; /**< name of our PID file */
char default_authname[] = "/etc/nbd_server.allow"; /**< default name of allow file */
/**
* Variables associated with a server.
**/
typedef struct {
char* exportname; /**< (unprocessed) filename of the file we're exporting */
off_t hunksize; /**< size of a hunk of an exported file */
off_t expected_size; /**< size of the exported file as it was told to
us through configuration */
unsigned int port; /**< port we're exporting this file at */
char* authname; /**< filename of the authorization file */
int flags; /**< flags associated with this exported file */
unsigned int timeout;/**< how long a connection may be idle
(0=forever) */
int socket; /**< The socket of this server. */
} SERVER;
/**
* Variables associated with a client socket.
**/
typedef struct {
off_t exportsize; /**< size of the file we're exporting */
char *clientname; /**< peer */
char *exportname; /**< (processed) filename of the file we're exporting */
GArray *export; /**< array of filedescriptors of exported files;
only the first is actually used unless we're
doing the multiple file option */
int net; /**< The actual client socket */
SERVER *server; /**< The server this client is getting data from */
char* difffilename; /**< filename of the copy-on-write file, if any */
int difffile; /**< filedescriptor of copyonwrite file. @todo
shouldn't this be an array too? (cfr export) Or
make -m and -c mutually exclusive */
u32 difffilelen; /**< number of pages in difffile */
u32 *difmap; /**< see comment on the global difmap for this one */
} CLIENT;
/**
* Check whether a client is allowed to connect. Works with an authorization
* file which contains one line per machine, no wildcards.
*
* @param name IP address of client trying to connect (in human-readable form)
* @return 0 - authorization refused, 1 - OK
**/
int authorized_client(CLIENT *opts) {
FILE *f ;
char line[LINELEN];
if ((f=fopen(opts->server->authname,"r"))==NULL) {
msg4(LOG_INFO,"Can't open authorization file %s (%s).",
opts->server->authname,strerror(errno)) ;
return 1 ;
}
while (fgets(line,LINELEN,f)!=NULL) {
if (strncmp(line,opts->clientname,strlen(opts->clientname))==0) {
fclose(f);
return 1;
}
}
fclose(f) ;
return 0 ;
}
/**
* Read data from a file descriptor into a buffer
*
* @param f a file descriptor
* @param buf a buffer
* @param len the number of bytes to be read
**/
inline void readit(int f, void *buf, size_t len) {
ssize_t res;
while (len > 0) {
DEBUG("*");
if ((res = read(f, buf, len)) <= 0)
err("Read failed: %m");
len -= res;
buf += res;
}
}
/**
* Write data from a buffer into a filedescriptor
*
* @param f a file descriptor
* @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) {
ssize_t res;
while (len > 0) {
DEBUG("+");
if ((res = write(f, buf, len)) <= 0)
err("Send failed: %m");
len -= res;
buf += res;
}
}
/**
* Print out a message about how to use nbd-server. Split out to a separate
* function so that we can call it from multiple places
*/
void usage() {
printf("This is nbd-server version " VERSION "\n");
printf("Usage: port file_to_export [size][kKmM] [-l authorize_file] [-r] [-m] [-c] [-a timeout_sec]\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-l|--authorize-file\tfile with list of hosts that are allowed to\n\t\t\t\tconnect.\n"
"\t-a|--idle-time\t\tmaximum idle seconds; server terminates when\n\t\t\t\tidle time exceeded\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" );
}
/**
* Parse the command line.
*
* @todo getopt() is a great thing, and easy to use. Also, we want to
* create a configuration file which nbd-server will read. Maybe do (as in,
* parse) that here.
*
* @param argc the argc argument to main()
* @param argv the argv argument to main()
**/
SERVER* cmdline(int argc, char *argv[]) {
int i=0;
int nonspecial=0;
int c;
struct option long_options[] = {
{"read-only", no_argument, NULL, 'r'},
{"multi-file", no_argument, NULL, 'm'},
{"copy-on-write", no_argument, NULL, 'c'},
{"authorize-file", required_argument, NULL, 'l'},
{"idle-time", required_argument, NULL, 'a'},
{0,0,0,0}
};
SERVER *serve;
off_t es;
size_t last;
char suffix;
serve=g_malloc(sizeof(SERVER));
serve->hunksize=OFFT_MAX;
while((c=getopt_long(argc, argv, "-a:cl:mr", long_options, &i))>=0) {
switch (c) {
case 1:
switch(nonspecial++) {
case 0:
serve->port=strtol(optarg, NULL, 0);
break;
case 1:
serve->exportname = g_strdup(optarg);
if(serve->exportname[0] != '/') {
fprintf(stderr, "E: The to be exported file needs to be an absolute filename!\n");
exit(EXIT_FAILURE);
}
break;
case 2:
last=strlen(optarg)-1;
suffix=optarg[last];
if (suffix == 'k' || suffix == 'K' ||
suffix == 'm' || suffix == 'M')
optarg[last] = '\0';
es = (off_t)atol(optarg);
switch (suffix) {
case 'm':
case 'M': es <<= 10;
case 'k':
case 'K': es <<= 10;
default : break;
}
serve->expected_size = es;
break;
}
break;
case 'r':
serve->flags |= F_READONLY;
break;
case 'm':
serve->flags |= F_MULTIFILE;
serve->hunksize = 1*GIGA;
serve->authname = default_authname;
break;
case 'c':
serve->flags |=F_COPYONWRITE;
break;
case 'l':
serve->authname=optarg;
break;
case 'a':
serve->timeout=strtol(optarg, NULL, 0);
break;
default:
usage();
exit(0);
break;
}
}
/* What's left: the port to export, the name of the to be exported
* file, and, optionally, the size of the file, in that order. */
if(nonspecial<2) {
usage();
exit(EXIT_FAILURE);
}
return serve;
}
/**
* Signal handler for SIGCHLD
* @param s the signal we're handling (must be SIGCHLD, or something
* is severely wrong)
**/
void sigchld_handler(int s) {
int status;
int* i;
pid_t pid;
int done=0;
while(!done && (pid=wait(&status)) > 0) {
if(WIFEXITED(status)) {
msg3(LOG_INFO, "Child exited with %d", WEXITSTATUS(status));
msg3(LOG_INFO, "pid is %d", pid);
done=1;
}
i=g_hash_table_lookup(children, &pid);
if(!i) {
msg3(LOG_INFO, "SIGCHLD received for an unknown child with PID %ld", (long)pid);
} else {
DEBUG2("Removing %d from the list of children", pid);
g_hash_table_remove(children, &pid);
}
}
}
/**
* Kill a child. Called from sigterm_handler::g_hash_table_foreach.
*
* @param key the key
* @param value the value corresponding to the above key
* @param user_data a pointer which we always set to 1, so that we know what
* will happen next.
**/
void killchild(gpointer key, gpointer value, gpointer user_data) {
pid_t *pid=value;
int *parent=user_data;
kill(*pid, SIGTERM);
*parent=1;
}
/**
* Handle SIGTERM and dispatch it to our children
* @param s the signal we're handling (must be SIGTERM, or something
* is severely wrong).
**/
void sigterm_handler(int s) {
int parent=0;
g_hash_table_foreach(children, killchild, &parent);
if(parent) {
unlink(pidfname);
}
exit(0);
}
/**
* Detect the size of a file.
*
* @param export An open filedescriptor
* @return the size of the file, or OFFT_MAX if detection was
* impossible.
**/
off_t size_autodetect(int export) {
off_t es;
unsigned long sectors;
struct stat stat_buf;
int error;
#ifdef HAVE_SYS_MOUNT_H
#ifdef HAVE_SYS_IOCTL_H
#ifdef BLKGETSIZE
DEBUG("looking for export size with ioctl BLKGETSIZE\n");
if (!ioctl(export, BLKGETSIZE, §ors) && sectors) {
es = (off_t)sectors * (off_t)512;
return es;
}
#endif /* BLKGETSIZE */
#endif /* HAVE_SYS_IOCTL_H */
#endif /* HAVE_SYS_MOUNT_H */
DEBUG("looking for export size with fstat\n");
stat_buf.st_size = 0;
error = fstat(export, &stat_buf);
if (!error) {
if(stat_buf.st_size > 0)
return (off_t)stat_buf.st_size;
} else {
err("fstat failed: %m");
}
DEBUG("looking for export size with lseek SEEK_END\n");
es = lseek(export, (off_t)0, SEEK_END);
if (es > ((off_t)0)) {
return es;
} else {
DEBUG2("lseek failed: %d", errno==EBADF?1:(errno==ESPIPE?2:(errno==EINVAL?3:4)));
}
err("Could not find size of exported block device: %m");
return OFFT_MAX;
}
/**
* seek to a position in a file, with error handling.
* @param handle a filedescriptor
* @param a position to seek to
* @todo get rid of this; lastpoint is a global variable right now, but it
* shouldn't be. If we pass it on as a parameter, that makes things a *lot*
* easier.
**/
void myseek(int handle,off_t a) {
if (lseek(handle, a, SEEK_SET) < 0) {
err("Can not seek locally!\n");
}
}
/**
* Write an amount of bytes at a given offset to the right file. This
* abstracts the write-side of the multiple file option.
*
* @param a The offset where the write should start
* @param buf The buffer to write from
* @param len The length of buf
* @return The number of bytes actually written, or -1 in case of an error
**/
int rawexpwrite(off_t a, char *buf, size_t len, CLIENT *client) {
ssize_t res;
myseek(g_array_index(client->export, int, (int)(a/client->server->hunksize)), a%client->server->hunksize);
;
res = write(g_array_index(client->export, int, (int)((off_t)a/(off_t)(client->server->hunksize))), buf, len);
return (res < 0 || (size_t)res != len);
}
/**
* Read an amount of bytes at a given offset from the right file. This
* abstracts the read-side of the multiple files option.
*
* @param a The offset where the read should start
* @param buf A buffer to read into
* @param len The size of buf
* @return The number of bytes actually read, or -1 in case of an
* error.
**/
int rawexpread(off_t a, char *buf, size_t len, CLIENT *client) {
ssize_t res;
myseek(g_array_index(client->export,int,(int)a/client->server->hunksize),
a%client->server->hunksize);
res = read(g_array_index(client->export,int,(int)a/client->server->hunksize), buf, len);
return (res < 0 || (size_t)res != len);
}
/**
* Read an amount of bytes at a given offset from the right file. This
* abstracts the read-side of the copyonwrite stuff, and calls
* rawexpread() with the right parameters to do the actual work.
* @param a The offset where the read should start
* @param buf A buffer to read into
* @param len The size of buf
* @return The number of bytes actually read, or -1 in case of an error
**/
int expread(off_t a, char *buf, size_t len, CLIENT *client) {
off_t rdlen, offset;
off_t mapcnt, mapl, maph, pagestart;
if (!(client->server->flags & F_COPYONWRITE))
return rawexpread(a, buf, len, client);
DEBUG3("Asked to read %d bytes at %Lu.\n", len, (unsigned long long)a);
mapl=a/DIFFPAGESIZE; maph=(a+len-1)/DIFFPAGESIZE;
for (mapcnt=mapl;mapcnt<=maph;mapcnt++) {
pagestart=mapcnt*DIFFPAGESIZE;
offset=a-pagestart;
rdlen=(0<DIFFPAGESIZE-offset && len<(size_t)(DIFFPAGESIZE-offset)) ?
len : (size_t)DIFFPAGESIZE-offset;
if (client->difmap[mapcnt]!=(u32)(-1)) { /* the block is already there */
DEBUG3("Page %Lu is at %lu\n", (unsigned long long)mapcnt,
(unsigned long)(client->difmap[mapcnt]));
myseek(client->difffile, client->difmap[mapcnt]*DIFFPAGESIZE+offset);
if (read(client->difffile, buf, rdlen) != rdlen) return -1;
} else { /* the block is not there */
DEBUG2("Page %Lu is not here, we read the original one\n",
(unsigned long long)mapcnt);
if(rawexpread(a, buf, rdlen, client)) return -1;
}
len-=rdlen; a+=rdlen; buf+=rdlen;
}
return 0;
}
/**
* Write an amount of bytes at a given offset to the right file. This
* abstracts the write-side of the copyonwrite option, and calls
* rawexpwrite() with the right parameters to do the actual work.
*
* @param a The offset where the write should start
* @param buf The buffer to write from
* @param len The length of buf
* @return The number of bytes actually written, or -1 in case of an error
**/
int expwrite(off_t a, char *buf, size_t len, CLIENT *client) {
char pagebuf[DIFFPAGESIZE];
off_t mapcnt,mapl,maph;
off_t wrlen,rdlen;
off_t pagestart;
off_t offset;
if (!(client->server->flags & F_COPYONWRITE))
return(rawexpwrite(a,buf,len, client));
DEBUG3("Asked to write %d bytes at %Lu.\n", len, (unsigned long long)a);
mapl=a/DIFFPAGESIZE ; maph=(a+len-1)/DIFFPAGESIZE ;
for (mapcnt=mapl;mapcnt<=maph;mapcnt++) {
pagestart=mapcnt*DIFFPAGESIZE ;
offset=a-pagestart ;
wrlen=(0<DIFFPAGESIZE-offset && len<(size_t)(DIFFPAGESIZE-offset)) ?
len : (size_t)DIFFPAGESIZE-offset;
if (client->difmap[mapcnt]!=(u32)(-1)) { /* the block is already there */
DEBUG3("Page %Lu is at %lu\n", (unsigned long long)mapcnt,
(unsigned long)(client->difmap[mapcnt])) ;
myseek(client->difffile,
client->difmap[mapcnt]*DIFFPAGESIZE+offset);
if (write(client->difffile, buf, wrlen) != wrlen) return -1 ;
} else { /* the block is not there */
myseek(client->difffile,client->difffilelen*DIFFPAGESIZE) ;
client->difmap[mapcnt]=client->difffilelen++ ;
DEBUG3("Page %Lu is not here, we put it at %lu\n",
(unsigned long long)mapcnt,
(unsigned long)(client->difmap[mapcnt]));
rdlen=DIFFPAGESIZE ;
if (rdlen+pagestart%(client->server->hunksize) >
(client->server->hunksize))
rdlen=client->server->hunksize -
(pagestart%client->server->hunksize);
if (rawexpread(pagestart, pagebuf, rdlen, client))
return -1;
memcpy(pagebuf+offset,buf,wrlen) ;
if (write(client->difffile, pagebuf, DIFFPAGESIZE) !=
DIFFPAGESIZE)
return -1;
}
len-=wrlen ; a+=wrlen ; buf+=wrlen ;
}
return 0;
}
/**
* Do the initial negotiation.
*
* @param net A socket to do the negotiation over
**/
void negotiate(CLIENT *client) {
char zeros[300];
u64 size_host;
memset(zeros, 0, 290);
if (write(client->net, INIT_PASSWD, 8) < 0)
err("Negotiation failed: %m");
cliserv_magic = htonll(cliserv_magic);
if (write(client->net, &cliserv_magic, sizeof(cliserv_magic)) < 0)
err("Negotiation failed: %m");
size_host = htonll((u64)(client->exportsize));
if (write(client->net, &size_host, 8) < 0)
err("Negotiation failed: %m");
if (write(client->net, zeros, 128) < 0)
err("Negotiation failed: %m");
}
/** sending macro. */
#define SEND(net,reply) writeit( net, &reply, sizeof( reply ));
/** error macro. */
#define ERROR(client,reply) { reply.error = htonl(-1); SEND(client->net,reply); reply.error = 0; }
/**
* Serve a file to a single client.
*
* @todo This beast needs to be split up in many tiny little manageable
* pieces. Preferably with a chainsaw.
*
* @param net A network socket, connected to an nbd client
* @return never
**/
int mainloop(CLIENT *client) {
struct nbd_request request;
struct nbd_reply reply;
gboolean go_on=TRUE;
#ifdef DODBG
int i = 0;
#endif
negotiate(client);
DEBUG("Entering request loop!\n");
reply.magic = htonl(NBD_REPLY_MAGIC);
reply.error = 0;
while (go_on) {
char buf[BUFSIZE];
size_t len;
#ifdef DODBG
i++;
printf("%d: ", i);
#endif
if (client->server->timeout)
alarm(client->server->timeout);
readit(client->net, &request, sizeof(request));
request.from = ntohll(request.from);
request.type = ntohl(request.type);
if (request.type==NBD_CMD_DISC) {
msg2(LOG_INFO, "Disconnect request received.");
if (client->difmap) g_free(client->difmap) ;
if (client->difffile>=0) {
close(client->difffile);
unlink(client->difffilename);
free(client->difffilename);
}
go_on=FALSE;
continue;
}
len = ntohl(request.len);
if (request.magic != htonl(NBD_REQUEST_MAGIC))
err("Not enough magic.");
if (len > BUFSIZE-sizeof(struct nbd_reply))
err("Request too big!");
#ifdef DODBG
printf("%s from %Lu (%Lu) len %d, ", request.type ? "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);
continue;
}
if (((ssize_t)((off_t)request.from + len) > client->exportsize) ||
((client->server->flags & F_READONLY) && request.type)) {
DEBUG("[RANGE!]");
readit(client->net, buf, len);
ERROR(client, reply);
continue;
}
if (request.type==NBD_CMD_WRITE) {
DEBUG("wr: net->buf, ");
readit(client->net, buf, len);
DEBUG("buf->exp, ");
if ((client->server->flags & F_AUTOREADONLY) ||
expwrite(request.from, buf, len,
client)) {
DEBUG("Write failed: %m" );
ERROR(client, reply);
continue;
}
SEND(client->net, reply);
DEBUG("OK!\n");
continue;
}
/* READ */
DEBUG("exp->buf, ");
if (expread(request.from, buf + sizeof(struct nbd_reply), len, client)) {
DEBUG("Read failed: %m");
ERROR(client, reply);
continue;
}
DEBUG("buf->net, ");
memcpy(buf, &reply, sizeof(struct nbd_reply));
writeit(client->net, buf, len + sizeof(struct nbd_reply));
DEBUG("OK!\n");
}
return 0;
}
/**
* Split a single exportfile into multiple ones, if that was asked.
* @return 0 on success, -1 on failure
* @param client information on the client which we want to split
**/
int splitexport(CLIENT* client) {
off_t i;
int fhandle;
client->export = g_array_new(TRUE, TRUE, sizeof(int));
for (i=0; i<client->exportsize; i+=client->server->hunksize) {
gchar *tmpname;
if(client->server->flags & F_MULTIFILE) {
tmpname=g_strdup_printf("%s.%d", client->exportname,
(int)(i/client->server->hunksize));
} else {
tmpname=g_strdup(client->exportname);
}
DEBUG2( "Opening %s\n", tmpname );
if((fhandle = open(tmpname, (client->server->flags & F_READONLY) ? O_RDONLY : O_RDWR)) == -1) {
/* Read WRITE ACCESS was requested by media is only read only */
client->server->flags |= F_AUTOREADONLY;
client->server->flags |= F_READONLY;
if((fhandle = open(tmpname, O_RDONLY)) == -1)
err("Could not open exported file: %m");
}
g_array_insert_val(client->export,i/client->server->hunksize,fhandle);
g_free(tmpname);
}
return 0;
}
int copyonwrite_prepare(CLIENT* client)
{
off_t i;
if ((client->difffilename = malloc(1024))==NULL)
err("Failed to allocate string for diff file name");
snprintf(client->difffilename, 1024, "%s-%s-%d.diff",client->exportname,client->clientname,
(int)getpid()) ;
client->difffilename[1023]='\0';
msg3(LOG_INFO,"About to create map and diff file %s",client->difffilename) ;
client->difffile=open(client->difffilename,O_RDWR | O_CREAT | O_TRUNC,0600) ;
if (client->difffile<0) err("Could not create diff file (%m)") ;
if ((client->difmap=calloc(client->exportsize/DIFFPAGESIZE,sizeof(u32)))==NULL)
err("Could not allocate memory") ;
for (i=0;i<client->exportsize/DIFFPAGESIZE;i++) client->difmap[i]=(u32)-1 ;
return 0;
}
/**
* Serve a connection.
*
* @todo allow for multithreading, perhaps use libevent. Not just yet, though;
* follow the road map.
*
* @param net A network socket connected to an nbd client
**/
void serveconnection(CLIENT *client) {
splitexport(client);
if (!client->server->expected_size) {
client->exportsize = size_autodetect(g_array_index(client->export,int,0));
} else {
/* Perhaps we should check first. Not now. */
client->exportsize = client->server->expected_size;
}
if (client->exportsize > OFFT_MAX) {
/* uhm, well... In a parallel universe, this *might* be
* possible... */
err("Size of exported file is too big\n");
}
else {
msg3(LOG_INFO, "size of exported file/device is %Lu", (unsigned long long)client->exportsize);
}
if (client->server->flags & F_COPYONWRITE) {
copyonwrite_prepare(client);
}
setmysockopt(client->net);
mainloop(client);
}
/**
* Find the name of the file we have to serve. This will use g_strdup_printf
* to put the IP address of the client inside a filename containing
* "%s". That name is then written to client->exportname.
*
* @param net A socket connected to an nbd client
* @param client information about the client. The IP address in human-readable
* format will be written to a new char* buffer, the address of which will be
* stored in client->clientname.
**/
void set_peername(int net, CLIENT *client) {
struct sockaddr_in addrin;
int addrinlen = sizeof( addrin );
char *peername ;
if (getpeername(net, (struct sockaddr *) &addrin, (socklen_t *)&addrinlen) < 0)
err("getsockname failed: %m");
peername = inet_ntoa(addrin.sin_addr);
client->exportname=g_strdup_printf(client->server->exportname, peername);
msg4(LOG_INFO, "connect from %s, assigned file is %s",
peername, client->exportname);
client->clientname=g_strdup(peername);
}
/**
* Destroy a pid_t*
* @param data a pointer to pid_t which should be freed
**/
void destroy_pid_t(gpointer data) {
g_free(data);
}
/**
* Go daemon (unless we specified at compile time that we didn't want this)
* @param serve the first server of our configuration. If its port is zero,
* then do not daemonize, because we're doing inetd then.
**/
#if !defined(NODAEMON) && !defined(NOFORK)
void daemonize(SERVER* serve) {
FILE*pidf;
if((serve->port)) {
if(daemon(0,0)<0) {
err("daemon");
}
snprintf(pidfname, sizeof(char)*255, "/var/run/nbd-server.%d.pid", serve->port);
pidf=fopen(pidfname, "w");
if(pidf) {
fprintf(pidf,"%d", (int)getpid());
fclose(pidf);
} else {
perror("fopen");
fprintf(stderr, "Not fatal; continuing");
}
}
}
#else
#define daemonize(serve)
#endif /* !defined(NODAEMON) && !defined(NOFORK) */
/**
* Connect a server's socket.
*
* @todo modularize this giant beast. Preferably with a chainsaw. Also,
* it has no business starting mainloop(), through serveconnection(); it
* should connect, and be done with it.
*
* @param serve the server we want to connect.
**/
void setup_serve(SERVER* serve) {
struct sockaddr_in addrin;
struct sigaction sa;
int addrinlen = sizeof(addrin);
int fhandle;
#ifndef sun
int yes=1;
#else
char yes='1';
#endif /* sun */
if (strstr(serve->exportname, "%s") == NULL) {
/**
* verify the existence of the block device that
* this server instance will export
**/
DEBUG2( "Opening %s\n", serve->exportname );
if ((fhandle = open(serve->exportname,
(serve->flags & F_READONLY) ? O_RDONLY : O_RDWR)) == -1) {
err("Could not open exported file: %m");
}
/**
* if the exported file's size can't be detected
* size_autodetect() will exit()... and export can be
* considered invalid
**/
size_autodetect(fhandle);
close(fhandle);
}
daemonize(serve);
if ((serve->socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
err("socket: %m");
/* lose the pesky "Address already in use" error message */
if (setsockopt(serve->socket,SOL_SOCKET,SO_REUSEADDR,&yes,sizeof(int)) == -1) {
err("setsockopt SO_REUSEADDR");
}
if (setsockopt(serve->socket,SOL_SOCKET,SO_KEEPALIVE,&yes,sizeof(int)) == -1) {
err("setsockopt SO_KEEPALIVE");
}
DEBUG("Waiting for connections... bind, ");
addrin.sin_family = AF_INET;
addrin.sin_port = htons(serve->port);
addrin.sin_addr.s_addr = 0;
if (bind(serve->socket, (struct sockaddr *) &addrin, addrinlen) < 0)
err("bind: %m");
DEBUG("listen, ");
if (listen(serve->socket, 1) < 0)
err("listen: %m");
sa.sa_handler = sigchld_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if(sigaction(SIGCHLD, &sa, NULL) == -1)
err("sigaction: %m");
sa.sa_handler = sigterm_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
if(sigaction(SIGTERM, &sa, NULL) == -1)
err("sigaction: %m");
children=g_hash_table_new_full(g_int_hash, g_int_equal, NULL, destroy_pid_t);
}
/**
* Loop through the available servers, and serve them.
*
* Actually, right now we only handle one server. Will change that for
* 2.9.
**/
int serveloop(SERVER* serve) {
struct sockaddr_in addrin;
socklen_t addrinlen=sizeof(addrin);
for(;;) {
CLIENT *client;
int net;
pid_t *pid;
DEBUG("accept, ");
if ((net = accept(serve->socket, (struct sockaddr *) &addrin, &addrinlen)) < 0) {
msg2(LOG_ERR,"accept: %m");
continue;
}
client = g_malloc(sizeof(CLIENT));
client->server=serve;
client->exportsize=OFFT_MAX;
client->net=net;
set_peername(net, client);
if (!authorized_client(client)) {
msg2(LOG_INFO,"Unauthorized client") ;
close(net) ;
continue ;
}
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);
close(serve->socket) ;
#endif // NOFORK
msg2(LOG_INFO,"Starting to serve") ;
serveconnection(client);
return 0;
}
}
/**
* Main entry point...
**/
int main(int argc, char *argv[]) {
SERVER* serve;
GArray* servers;
if (sizeof( struct nbd_request )!=28) {
fprintf(stderr,"Bad size of structure. Alignment problems?\n");
exit(-1) ;
}
logging();
serve=cmdline(argc, argv);
servers=g_array_new(TRUE, FALSE, sizeof(SERVER*));
if (!(serve->port)) {
CLIENT *client;
#ifndef ISSERVER
/* You really should define ISSERVER if you're going to use
* inetd mode, but if you don't, closing stdout and stderr
* (which inetd had connected to the client socket) will let it
* work. */
close(1);
close(2);
open("/dev/null", O_WRONLY);
open("/dev/null", O_WRONLY);
#endif
client=g_malloc(sizeof(CLIENT));
client->server=serve;
client->net=0;
client->exportsize=OFFT_MAX;
set_peername(0,client);
serveconnection(client);
return 0;
}
setup_serve(serve);
serveloop(serve);
return 0 ;
}
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