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nbd  3.2
Defines | Functions
nbd-client.c File Reference
#include "config.h"
#include "lfs.h"
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <netinet/tcp.h>
#include <netinet/in.h>
#include <netdb.h>
#include "netdb-compat.h"
#include <stdio.h>
#include <fcntl.h>
#include <syslog.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/mman.h>
#include <signal.h>
#include <errno.h>
#include <getopt.h>
#include <stdarg.h>
#include <linux/ioctl.h>
#include "cliserv.h"

Go to the source code of this file.

Defines

#define MY_NAME   "nbd_client"
#define NBDC_DO_LIST   1

Functions

int check_conn (char *devname, int do_print)
int opennet (char *name, char *portstr, int sdp)
void ask_list (int sock)
void negotiate (int sock, u64 *rsize64, u32 *flags, char *name, uint32_t needed_flags, uint32_t client_flags, uint32_t do_opts)
void setsizes (int nbd, u64 size64, int blocksize, u32 flags)
void set_timeout (int nbd, int timeout)
void finish_sock (int sock, int nbd, int swap)
static int oom_adjust (const char *file, const char *value)
void usage (char *errmsg,...)
void disconnect (char *device)
int main (int argc, char *argv[])

Define Documentation

#define MY_NAME   "nbd_client"

Definition at line 44 of file nbd-client.c.

#define NBDC_DO_LIST   1

Definition at line 51 of file nbd-client.c.


Function Documentation

void ask_list ( int  sock)

Definition at line 133 of file nbd-client.c.

                        {
       uint32_t opt;
       uint32_t opt_server;
       uint32_t len;
       uint32_t reptype;
       uint64_t magic;
       char buf[1024];

       magic = ntohll(opts_magic);
       if (write(sock, &magic, sizeof(magic)) < 0)
              err("Failed/2.2: %m");

       /* Ask for the list */
       opt = htonl(NBD_OPT_LIST);
       if(write(sock, &opt, sizeof(opt)) < 0) {
              err("writing list option failed: %m");
       }
       /* Send the length (zero) */
       len = htonl(0);
       if(write(sock, &len, sizeof(len)) < 0) {
              err("writing length failed: %m");
       }
       /* newline, move away from the "Negotiation:" line */
       printf("\n");
       do {
              memset(buf, 0, 1024);
              if(read(sock, &magic, sizeof(magic)) < 0) {
                     err("Reading magic from server: %m");
              }
              if(read(sock, &opt_server, sizeof(opt_server)) < 0) {
                     err("Reading option: %m");
              }
              if(read(sock, &reptype, sizeof(reptype)) <0) {
                     err("Reading reply from server: %m");
              }
              if(read(sock, &len, sizeof(len)) < 0) {
                     err("Reading length from server: %m");
              }
              magic=ntohll(magic);
              len=ntohl(len);
              reptype=ntohl(reptype);
              if(magic != rep_magic) {
                     err("Not enough magic from server");
              }
              if(reptype & NBD_REP_FLAG_ERROR) {
                     switch(reptype) {
                            case NBD_REP_ERR_POLICY:
                                   fprintf(stderr, "\nE: listing not allowed by server.\n");
                                   break;
                            default:
                                   fprintf(stderr, "\nE: unexpected error from server.\n");
                                   break;
                     }
                     if(len) {
                            if(read(sock, buf, len) < 0) {
                                   fprintf(stderr, "\nE: could not read error message from server\n");
                            }
                            fprintf(stderr, "Server said: %s\n", buf);
                     }
                     exit(EXIT_FAILURE);
              } else {
                     if(len) {
                            if(reptype != NBD_REP_SERVER) {
                                   err("Server sent us a reply we don't understand!");
                            }
                            if(read(sock, &len, sizeof(len)) < 0) {
                                   fprintf(stderr, "\nE: could not read export name length from server\n");
                                   exit(EXIT_FAILURE);
                            }
                            len=ntohl(len);
                            if(read(sock, buf, len) < 0) {
                                   fprintf(stderr, "\nE: could not read export name from server\n");
                                   exit(EXIT_FAILURE);
                            }
                            printf("%s\n", buf);
                     }
              }
       } while(reptype != NBD_REP_ACK);
       opt=htonl(NBD_OPT_ABORT);
       len=htonl(0);
       magic=htonll(opts_magic);
       if (write(sock, &magic, sizeof(magic)) < 0)
              err("Failed/2.2: %m");
       if (write(sock, &opt, sizeof(opt)) < 0)
              err("Failed writing abort");
       if (write(sock, &len, sizeof(len)) < 0)
              err("Failed writing length");
}

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int check_conn ( char *  devname,
int  do_print 
)

Definition at line 53 of file nbd-client.c.

                                            {
       char buf[256];
       char* p;
       int fd;
       int len;

       if( (p=strrchr(devname, '/')) ) {
              devname=p+1;
       }
       if((p=strchr(devname, 'p'))) {
              /* We can't do checks on partitions. */
              *p='\0';
       }
       snprintf(buf, 256, "/sys/block/%s/pid", devname);
       if((fd=open(buf, O_RDONLY))<0) {
              if(errno==ENOENT) {
                     return 1;
              } else {
                     return 2;
              }
       }
       len=read(fd, buf, 256);
       buf[len-1]='\0';
       if(do_print) printf("%s\n", buf);
       return 0;
}

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void disconnect ( char *  device)

Definition at line 416 of file nbd-client.c.

                              {
       int nbd = open(device, O_RDWR);

       if (nbd < 0)
              err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");
       printf("Disconnecting: que, ");
       if (ioctl(nbd, NBD_CLEAR_QUE)< 0)
              err("Ioctl failed: %m\n");
       printf("disconnect, ");
#ifdef NBD_DISCONNECT
       if (ioctl(nbd, NBD_DISCONNECT)<0)
              err("Ioctl failed: %m\n");
       printf("sock, ");
#else
       fprintf(stderr, "Can't disconnect: I was not compiled with disconnect support!\n" );
       exit(1);
#endif
       if (ioctl(nbd, NBD_CLEAR_SOCK)<0)
              err("Ioctl failed: %m\n");
       printf("done\n");
}

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void finish_sock ( int  sock,
int  nbd,
int  swap 
)

Definition at line 369 of file nbd-client.c.

                                              {
       if (ioctl(nbd, NBD_SET_SOCK, sock) < 0)
              err("Ioctl NBD_SET_SOCK failed: %m\n");

       if (swap)
              mlockall(MCL_CURRENT | MCL_FUTURE);
}

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int main ( int  argc,
char *  argv[] 
)

Definition at line 438 of file nbd-client.c.

                                 {
       char* port=NULL;
       int sock, nbd;
       int blocksize=1024;
       char *hostname=NULL;
       char *nbddev=NULL;
       int swap=0;
       int cont=0;
       int timeout=0;
       int sdp=0;
       int G_GNUC_UNUSED nofork=0; // if -dNOFORK
       u64 size64;
       u32 flags;
       int c;
       int nonspecial=0;
       char* name=NULL;
       uint32_t needed_flags=0;
       uint32_t cflags=0;
       uint32_t opts=0;
       struct option long_options[] = {
              { "block-size", required_argument, NULL, 'b' },
              { "check", required_argument, NULL, 'c' },
              { "disconnect", required_argument, NULL, 'd' },
              { "help", no_argument, NULL, 'h' },
              { "list", no_argument, NULL, 'l' },
              { "name", required_argument, NULL, 'N' },
              { "nofork", no_argument, NULL, 'n' },
              { "persist", no_argument, NULL, 'p' },
              { "sdp", no_argument, NULL, 'S' },
              { "swap", no_argument, NULL, 's' },
              { "timeout", required_argument, NULL, 't' },
              { 0, 0, 0, 0 }, 
       };

       logging();

       while((c=getopt_long_only(argc, argv, "-b:c:d:hlnN:pSst:", long_options, NULL))>=0) {
              switch(c) {
              case 1:
                     // non-option argument
                     if(strchr(optarg, '=')) {
                            // old-style 'bs=' or 'timeout='
                            // argument
                            fprintf(stderr, "WARNING: old-style command-line argument encountered. This is deprecated.\n");
                            if(!strncmp(optarg, "bs=", 3)) {
                                   optarg+=3;
                                   goto blocksize;
                            }
                            if(!strncmp(optarg, "timeout=", 8)) {
                                   optarg+=8;
                                   goto timeout;
                            }
                            usage("unknown option %s encountered", optarg);
                            exit(EXIT_FAILURE);
                     }
                     switch(nonspecial++) {
                            case 0:
                                   // host
                                   hostname=optarg;
                                   break;
                            case 1:
                                   // port
                                   if(!strtol(optarg, NULL, 0)) {
                                          // not parseable as a number, assume it's the device and we have a name
                                          nbddev = optarg;
                                          nonspecial++;
                                   } else {
                                          port = optarg;
                                   }
                                   break;
                            case 2:
                                   // device
                                   nbddev = optarg;
                                   break;
                            default:
                                   usage("too many non-option arguments specified");
                                   exit(EXIT_FAILURE);
                     }
                     break;
              case 'b':
                    blocksize:
                     blocksize=(int)strtol(optarg, NULL, 0);
                     break;
              case 'c':
                     return check_conn(optarg, 1);
              case 'd':
                     disconnect(optarg);
                     exit(EXIT_SUCCESS);
              case 'h':
                     usage(NULL);
                     exit(EXIT_SUCCESS);
              case 'l':
                     needed_flags |= NBD_FLAG_FIXED_NEWSTYLE;
                     cflags |= NBD_FLAG_C_FIXED_NEWSTYLE;
                     opts |= NBDC_DO_LIST;
                     name="";
                     nbddev="";
                     port = NBD_DEFAULT_PORT;
                     break;
              case 'n':
                     nofork=1;
                     break;
              case 'N':
                     name=optarg;
                     if(!port) {
                            port = NBD_DEFAULT_PORT;
                     }
                     break;
              case 'p':
                     cont=1;
                     break;
              case 's':
                     swap=1;
                     break;
              case 'S':
                     sdp=1;
                     break;
              case 't':
                    timeout:
                     timeout=strtol(optarg, NULL, 0);
                     break;
              default:
                     fprintf(stderr, "E: option eaten by 42 mice\n");
                     exit(EXIT_FAILURE);
              }
       }

       if((!port && !name) || !hostname || !nbddev) {
              usage("not enough information specified");
              exit(EXIT_FAILURE);
       }

       sock = opennet(hostname, port, sdp);
       if (sock < 0)
              exit(EXIT_FAILURE);

       negotiate(sock, &size64, &flags, name, needed_flags, cflags, opts);

       nbd = open(nbddev, O_RDWR);
       if (nbd < 0)
         err("Cannot open NBD: %m\nPlease ensure the 'nbd' module is loaded.");

       setsizes(nbd, size64, blocksize, flags);
       set_timeout(nbd, timeout);
       finish_sock(sock, nbd, swap);
       if (swap) {
              /* try linux >= 2.6.36 interface first */
              if (oom_adjust("/proc/self/oom_score_adj", "-1000")) {
                     /* fall back to linux <= 2.6.35 interface */
                     oom_adjust("/proc/self/oom_adj", "-17");
              }
       }

       /* Go daemon */
       
#ifndef NOFORK
       if(!nofork) {
              if (daemon(0,0) < 0)
                     err("Cannot detach from terminal");
       }
#endif
       do {
#ifndef NOFORK
#ifdef SA_NOCLDWAIT
              struct sigaction sa;

              sa.sa_handler = SIG_DFL;
              sigemptyset(&sa.sa_mask);
              sa.sa_flags = SA_NOCLDWAIT;
              if (sigaction(SIGCHLD, &sa, NULL) < 0)
                     err("sigaction: %m");
#endif

              if (!fork()) {
                     /* Due to a race, the kernel NBD driver cannot
                      * call for a reread of the partition table
                      * in the handling of the NBD_DO_IT ioctl().
                      * Therefore, this is done in the first open()
                      * of the device. We therefore make sure that
                      * the device is opened at least once after the
                      * connection was made. This has to be done in a
                      * separate process, since the NBD_DO_IT ioctl()
                      * does not return until the NBD device has
                      * disconnected.
                      */
                     while(check_conn(nbddev, 0)) {
                            sleep(1);
                     }
                     open(nbddev, O_RDONLY);
                     exit(0);
              }
#endif

              if (ioctl(nbd, NBD_DO_IT) < 0) {
                      int error = errno;
                     fprintf(stderr, "nbd,%d: Kernel call returned: %d", getpid(), error);
                     if(error==EBADR) {
                            /* The user probably did 'nbd-client -d' on us.
                             * quit */
                            cont=0;
                     } else {
                            if(cont) {
                                   u64 new_size;
                                   u32 new_flags;

                                   close(sock); close(nbd);
                                   for (;;) {
                                          fprintf(stderr, " Reconnecting\n");
                                          sock = opennet(hostname, port, sdp);
                                          if (sock >= 0)
                                                 break;
                                          sleep (1);
                                   }
                                   nbd = open(nbddev, O_RDWR);
                                   if (nbd < 0)
                                          err("Cannot open NBD: %m");
                                   negotiate(sock, &new_size, &new_flags, name, needed_flags, cflags, opts);
                                   if (size64 != new_size) {
                                          err("Size of the device changed. Bye");
                                   }
                                   setsizes(nbd, size64, blocksize,
                                                        new_flags);

                                   set_timeout(nbd, timeout);
                                   finish_sock(sock,nbd,swap);
                            }
                     }
              } else {
                     /* We're on 2.4. It's not clearly defined what exactly
                      * happened at this point. Probably best to quit, now
                      */
                     fprintf(stderr, "Kernel call returned.");
                     cont=0;
              }
       } while(cont);
       printf("Closing: que, ");
       ioctl(nbd, NBD_CLEAR_QUE);
       printf("sock, ");
       ioctl(nbd, NBD_CLEAR_SOCK);
       printf("done\n");
       return 0;
}

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void negotiate ( int  sock,
u64 *  rsize64,
u32 *  flags,
char *  name,
uint32_t  needed_flags,
uint32_t  client_flags,
uint32_t  do_opts 
)

Definition at line 222 of file nbd-client.c.

                                                                                                                               {
       u64 magic, size64;
       uint16_t tmp;
       char buf[256] = "\0\0\0\0\0\0\0\0\0";

       printf("Negotiation: ");
       if (read(sock, buf, 8) < 0)
              err("Failed/1: %m");
       if (strlen(buf)==0)
              err("Server closed connection");
       if (strcmp(buf, INIT_PASSWD))
              err("INIT_PASSWD bad");
       printf(".");
       if (read(sock, &magic, sizeof(magic)) < 0)
              err("Failed/2: %m");
       magic = ntohll(magic);
       if(name) {
              uint32_t opt;
              uint32_t namesize;

              if (magic != opts_magic)
                     err("Not enough opts_magic");
              printf(".");
              if(read(sock, &tmp, sizeof(uint16_t)) < 0) {
                     err("Failed reading flags: %m");
              }
              *flags = ((u32)ntohs(tmp));
              if((needed_flags & *flags) != needed_flags) {
                     /* There's currently really only one reason why this
                      * check could possibly fail, but we may need to change
                      * this error message in the future... */
                     fprintf(stderr, "\nE: Server does not support listing exports\n");
                     exit(EXIT_FAILURE);
              }

              client_flags = htonl(client_flags);
              if (write(sock, &client_flags, sizeof(client_flags)) < 0)
                     err("Failed/2.1: %m");

              if(do_opts & NBDC_DO_LIST) {
                     ask_list(sock);
                     exit(EXIT_SUCCESS);
              }

              /* Write the export name that we're after */
              magic = htonll(opts_magic);
              if (write(sock, &magic, sizeof(magic)) < 0)
                     err("Failed/2.2: %m");

              opt = ntohl(NBD_OPT_EXPORT_NAME);
              if (write(sock, &opt, sizeof(opt)) < 0)
                     err("Failed/2.3: %m");
              namesize = (u32)strlen(name);
              namesize = ntohl(namesize);
              if (write(sock, &namesize, sizeof(namesize)) < 0)
                     err("Failed/2.4: %m");
              if (write(sock, name, strlen(name)) < 0)
                     err("Failed/2.4: %m");
       } else {
              if (magic != cliserv_magic)
                     err("Not enough cliserv_magic");
              printf(".");
       }

       if (read(sock, &size64, sizeof(size64)) < 0)
              err("Failed/3: %m\n");
       size64 = ntohll(size64);

#ifdef NBD_SET_SIZE_BLOCKS
       if ((size64>>12) > (uint64_t)~0UL) {
              printf("size = %luMB", (unsigned long)(size64>>20));
              err("Exported device is too big for me. Get 64-bit machine :-(\n");
       } else
              printf("size = %luMB", (unsigned long)(size64>>20));
#else
       if (size64 > (~0UL >> 1)) {
              printf("size = %luKB", (unsigned long)(size64>>10));
              err("Exported device is too big. Get 64-bit machine or newer kernel :-(\n");
       } else
              printf("size = %lu", (unsigned long)(size64));
#endif

       if(!name) {
              if (read(sock, flags, sizeof(*flags)) < 0)
                     err("Failed/4: %m\n");
              *flags = ntohl(*flags);
       } else {
              if(read(sock, &tmp, sizeof(tmp)) < 0)
                     err("Failed/4: %m\n");
              *flags |= (uint32_t)ntohs(tmp);
       }

       if (read(sock, &buf, 124) < 0)
              err("Failed/5: %m\n");
       printf("\n");

       *rsize64 = size64;
}

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static int oom_adjust ( const char *  file,
const char *  value 
) [static]

Definition at line 378 of file nbd-client.c.

{
       int fd, rc;
       size_t len;

       fd = open(file, O_WRONLY);
       if (fd < 0)
              return -1;
       len = strlen(value);
       rc = write(fd, value, len) != (ssize_t) len;
       close(fd);
       return rc ? -1 : 0;
}

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int opennet ( char *  name,
char *  portstr,
int  sdp 
)

Definition at line 80 of file nbd-client.c.

                                                {
       int sock;
       struct addrinfo hints;
       struct addrinfo *ai = NULL;
       struct addrinfo *rp = NULL;
       int e;

       memset(&hints,'\0',sizeof(hints));
       hints.ai_family = AF_UNSPEC;
       hints.ai_socktype = SOCK_STREAM;
       hints.ai_flags = AI_ADDRCONFIG | AI_NUMERICSERV;
       hints.ai_protocol = IPPROTO_TCP;

       e = getaddrinfo(name, portstr, &hints, &ai);

       if(e != 0) {
              fprintf(stderr, "getaddrinfo failed: %s\n", gai_strerror(e));
              freeaddrinfo(ai);
              return -1;
       }

       if(sdp) {
#ifdef WITH_SDP
              if (ai->ai_family == AF_INET)
                     ai->ai_family = AF_INET_SDP;
              else (ai->ai_family == AF_INET6)
                     ai->ai_family = AF_INET6_SDP;
#else
              err("Can't do SDP: I was not compiled with SDP support!");
#endif
       }

       for(rp = ai; rp != NULL; rp = rp->ai_next) {
              sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);

              if(sock == -1)
                     continue;     /* error */

              if(connect(sock, rp->ai_addr, rp->ai_addrlen) != -1)
                     break;        /* success */
       }

       if (rp == NULL) {
              err_nonfatal("Socket failed: %m");
              return -1;
       }

       setmysockopt(sock);

       freeaddrinfo(ai);
       return sock;
}

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void set_timeout ( int  nbd,
int  timeout 
)

Definition at line 357 of file nbd-client.c.

                                       {
       if (timeout) {
#ifdef NBD_SET_TIMEOUT
              if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long)timeout) < 0)
                     err("Ioctl NBD_SET_TIMEOUT failed: %m\n");
              fprintf(stderr, "timeout=%d\n", timeout);
#else
              err("Ioctl NBD_SET_TIMEOUT cannot be called when compiled on a system that does not support it\n");
#endif
       }
}

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void setsizes ( int  nbd,
u64  size64,
int  blocksize,
u32  flags 
)

Definition at line 321 of file nbd-client.c.

                                                             {
       unsigned long size;
       int read_only = (flags & NBD_FLAG_READ_ONLY) ? 1 : 0;

#ifdef NBD_SET_SIZE_BLOCKS
       if (size64>>12 > (uint64_t)~0UL)
              err("Device too large.\n");
       else {
              if (ioctl(nbd, NBD_SET_BLKSIZE, 4096UL) < 0)
                     err("Ioctl/1.1a failed: %m\n");
              size = (unsigned long)(size64>>12);
              if (ioctl(nbd, NBD_SET_SIZE_BLOCKS, size) < 0)
                     err("Ioctl/1.1b failed: %m\n");
              if (ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long)blocksize) < 0)
                     err("Ioctl/1.1c failed: %m\n");
              fprintf(stderr, "bs=%d, sz=%llu bytes\n", blocksize, 4096ULL*size);
       }
#else
       if (size64 > (~0UL >> 1)) {
              err("Device too large.\n");
       } else {
              size = (unsigned long)size64;
              if (ioctl(nbd, NBD_SET_SIZE, size) < 0)
                     err("Ioctl NBD_SET_SIZE failed: %m\n");
       }
#endif

       ioctl(nbd, NBD_CLEAR_SOCK);

       /* ignore error as kernel may not support */
       ioctl(nbd, NBD_SET_FLAGS, (unsigned long) flags);

       if (ioctl(nbd, BLKROSET, (unsigned long) &read_only) < 0)
              err("Unable to set read-only attribute for device");
}

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void usage ( char *  errmsg,
  ... 
)

Definition at line 392 of file nbd-client.c.

                              {
       if(errmsg) {
              char tmp[256];
              va_list ap;
              va_start(ap, errmsg);
              snprintf(tmp, 256, "ERROR: %s\n\n", errmsg);
              vfprintf(stderr, tmp, ap);
              va_end(ap);
       } else {
              fprintf(stderr, "nbd-client version %s\n", PACKAGE_VERSION);
       }
       fprintf(stderr, "Usage: nbd-client host port nbd_device [-block-size|-b block size] [-timeout|-t timeout] [-swap|-s] [-sdp|-S] [-persist|-p] [-nofork|-n]\n");
       fprintf(stderr, "Or   : nbd-client -name|-N name host [port] nbd_device [-block-size|-b block size] [-timeout|-t timeout] [-swap|-s] [-sdp|-S] [-persist|-p] [-nofork|-n]\n");
       fprintf(stderr, "Or   : nbd-client -d nbd_device\n");
       fprintf(stderr, "Or   : nbd-client -c nbd_device\n");
       fprintf(stderr, "Or   : nbd-client -h|--help\n");
       fprintf(stderr, "Or   : nbd-client -l|--list host\n");
       fprintf(stderr, "Default value for blocksize is 1024 (recommended for ethernet)\n");
       fprintf(stderr, "Allowed values for blocksize are 512,1024,2048,4096\n"); /* will be checked in kernel :) */
       fprintf(stderr, "Note, that kernel 2.4.2 and older ones do not work correctly with\n");
       fprintf(stderr, "blocksizes other than 1024 without patches\n");
       fprintf(stderr, "Default value for port with -N is 10809. Note that port must always be numeric\n");
}

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