busybox/networking/nbd-client.c

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/*
* Copyright 2010 Rob Landley <rob@landley.net>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config NBDCLIENT
//config: bool "nbd-client (6 kb)"
//config: default y
//config: help
//config: Network block device client
//applet:IF_NBDCLIENT(APPLET_NOEXEC(nbd-client, nbdclient, BB_DIR_USR_SBIN, BB_SUID_DROP, nbdclient))
//kbuild:lib-$(CONFIG_NBDCLIENT) += nbd-client.o
#include "libbb.h"
#include <netinet/tcp.h>
#include <linux/fs.h>
#include <getopt.h>
#define NBD_SET_SOCK _IO(0xab, 0)
#define NBD_SET_BLKSIZE _IO(0xab, 1)
#define NBD_SET_SIZE _IO(0xab, 2)
#define NBD_DO_IT _IO(0xab, 3)
#define NBD_CLEAR_SOCK _IO(0xab, 4)
#define NBD_CLEAR_QUEUE _IO(0xab, 5)
#define NBD_PRINT_DEBUG _IO(0xab, 6)
#define NBD_SET_SIZE_BLOCKS _IO(0xab, 7)
#define NBD_DISCONNECT _IO(0xab, 8)
#define NBD_SET_TIMEOUT _IO(0xab, 9)
#define NBD_SET_FLAGS _IO(0xab, 10)
//usage:#define nbdclient_trivial_usage
//usage: "{ [-b BLKSIZE] [-N NAME] [-t SEC] [-p] HOST [PORT] | -d } BLOCKDEV"
//usage:#define nbdclient_full_usage "\n\n"
//usage: "Connect to HOST and provide network block device on BLOCKDEV"
//TODO: more compat with nbd-client version 3.17 -
//nbd-client host [ port ] nbd-device [ -connections num ] [ -sdp ] [ -swap ]
// [ -persist ] [ -nofork ] [ -nonetlink ] [ -systemd-mark ]
// [ -block-size block size ] [ -timeout seconds ] [ -name name ]
// [ -certfile certfile ] [ -keyfile keyfile ] [ -cacertfile cacertfile ]
// [ -tlshostname hostname ]
//nbd-client -unix path nbd-device [ -connections num ] [ -sdp ] [ -swap ]
// [ -persist ] [ -nofork ] [ -nonetlink ] [ -systemd-mark ]
// [ -block-size block size ] [ -timeout seconds ] [ -name name ]
//nbd-client nbd-device
//nbd-client -d nbd-device
//nbd-client -c nbd-device
//nbd-client -l host [ port ]
//nbd-client [ -netlink ] -l host
//
//Default value for blocksize is 4096
//Allowed values for blocksize are 512,1024,2048,4096
int nbdclient_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nbdclient_main(int argc, char **argv)
{
#if BB_MMU
bool nofork;
#endif
bool opt_d;
bool opt_p;
const char *host, *port, *device;
const char *name;
unsigned blksize, size_blocks;
unsigned timeout;
int ch;
struct nbd_header_t {
uint64_t magic1; // "NBDMAGIC"
uint64_t magic2; // old style: 0x420281861253 big endian
// // new style: 0x49484156454F5054 (IHAVEOPT)
} nbd_header;
struct old_nbd_header_t {
uint64_t devsize;
uint32_t flags;
char data[124];
} old_nbd_header;
struct new_nbd_header_t {
uint64_t devsize;
uint16_t transmission_flags;
char data[124];
} new_nbd_header;
struct nbd_opt_t {
uint64_t magic;
uint32_t opt;
uint32_t len;
} nbd_opts;
static const struct option long_options[] = {
{ "block-size", required_argument, NULL, 'b' },
{ "timeout" , required_argument, NULL, 't' },
{ "name" , required_argument, NULL, 'n' },
{ "persist" , no_argument , NULL, 'p' },
{ NULL }
};
BUILD_BUG_ON(offsetof(struct old_nbd_header_t, data) != 8 + 4);
BUILD_BUG_ON(offsetof(struct new_nbd_header_t, data) != 8 + 2);
#if !BB_MMU
bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
#endif
// Parse args. nbd-client uses stupid "one-dash long options" style :(
// Even though short forms (-b,-t,-N,-p) exist for all long opts,
// older manpages only contained long forms, which probably resulted
// in many scripts using them.
blksize = 4096;
timeout = 0;
name = ""; // use of "" instead of NULL simplifies strlen() later
opt_d = opt_p = 0;
while ((ch = getopt_long_only(argc, argv, "dN:", long_options, NULL)) != -1) {
switch (ch) {
case 'p': // -persist
opt_p = 1;
break;
case 'd': // -d
opt_d = 1;
break;
case 'b': // -block-size
blksize = xatou(optarg);
break;
case 't': // -timeout
timeout = xatou(optarg);
break;
case 'N': // -N
case 'n': // -name
name = optarg;
break;
default:
bb_show_usage();
}
}
argv += optind;
if (opt_d) { // -d
if (argv[0] && !argv[1]) {
int nbd = xopen(argv[0], O_RDWR);
ioctl(nbd, NBD_DISCONNECT);
ioctl(nbd, NBD_CLEAR_SOCK);
if (ENABLE_FEATURE_CLEAN_UP)
close(nbd);
return 0;
}
bb_show_usage();
}
// Allow only argv[] of: HOST [PORT] BLOCKDEV
if (!argv[0] || !argv[1] || (argv[2] && argv[3])) {
bb_show_usage();
}
host = argv[0];
port = argv[2] ? argv[1] : "10809";
device = argv[2] ? argv[2] : argv[1];
// Repeat until spanked if -persist
#if BB_MMU
nofork = 0;
#endif
do {
int sock, nbd;
int ro;
int proto_new; // 0 for old, 1 for new
#if BB_MMU
char *data;
#endif
// Make sure BLOCKDEV exists
nbd = xopen(device, O_RDWR);
// Find and connect to server
sock = create_and_connect_stream_or_die(host, xatou16(port));
setsockopt_1(sock, IPPROTO_TCP, TCP_NODELAY);
// Log on to the server
xread(sock, &nbd_header, 8 + 8);
if (memcmp(&nbd_header.magic1, "NBDMAGIC",
sizeof(nbd_header.magic1)) != 0
) {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die("login failed");
}
if (memcmp(&nbd_header.magic2,
"\x00\x00\x42\x02\x81\x86\x12\x53",
sizeof(nbd_header.magic2)) == 0
) {
proto_new = 0;
} else if (memcmp(&nbd_header.magic2, "IHAVEOPT", 8) == 0) {
proto_new = 1;
} else {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die("login failed");
}
if (!proto_new) {
xread(sock, &old_nbd_header,
sizeof(old_nbd_header.devsize) +
sizeof(old_nbd_header.flags) +
sizeof(old_nbd_header.data));
size_blocks = SWAP_BE64(old_nbd_header.devsize) / blksize;
ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long) blksize);
ioctl(nbd, NBD_SET_SIZE_BLOCKS, size_blocks);
ioctl(nbd, NBD_CLEAR_SOCK);
ro = !!(old_nbd_header.flags & htons(2));
#if BB_MMU
data = old_nbd_header.data;
#endif
} else {
unsigned namelen;
uint16_t handshake_flags;
xread(sock, &handshake_flags, sizeof(handshake_flags));
xwrite(sock, &const_int_0, sizeof(const_int_0)); // client_flags
memcpy(&nbd_opts.magic, "IHAVEOPT",
sizeof(nbd_opts.magic));
nbd_opts.opt = htonl(1); // NBD_OPT_EXPORT_NAME
namelen = strlen(name);
nbd_opts.len = htonl(namelen);
xwrite(sock, &nbd_opts,
sizeof(nbd_opts.magic) +
sizeof(nbd_opts.opt) +
sizeof(nbd_opts.len));
xwrite(sock, name, namelen);
xread(sock, &new_nbd_header,
sizeof(new_nbd_header.devsize) +
sizeof(new_nbd_header.transmission_flags) +
sizeof(new_nbd_header.data));
size_blocks = SWAP_BE64(new_nbd_header.devsize) / blksize;
ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long) blksize);
ioctl(nbd, NBD_SET_SIZE_BLOCKS, size_blocks);
ioctl(nbd, NBD_CLEAR_SOCK);
ioctl(nbd, NBD_SET_FLAGS,
ntohs(new_nbd_header.transmission_flags));
ro = !!(new_nbd_header.transmission_flags & htons(2));
#if BB_MMU
data = new_nbd_header.data;
#endif
}
if (ioctl(nbd, BLKROSET, &ro) < 0) {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_perror_msg_and_die("BLKROSET");
}
if (timeout) {
if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long) timeout)) {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_perror_msg_and_die("NBD_SET_TIMEOUT");
}
}
if (ioctl(nbd, NBD_SET_SOCK, sock)) {
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_perror_msg_and_die("NBD_SET_SOCK");
}
//if (swap) mlockall(MCL_CURRENT|MCL_FUTURE);
#if BB_MMU
// Open the device to force reread of the partition table.
// Need to do it in a separate process, since open(device)
// needs some other process to sit in ioctl(nbd, NBD_DO_IT).
if (fork() == 0) {
/* child */
char *s = strrchr(device, '/');
sprintf(data, "/sys/block/%.32s/pid", s ? s + 1 : device);
// Is it up yet?
for (;;) {
int fd = open(data, O_RDONLY);
if (fd >= 0) {
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
break;
}
sleep1();
}
open(device, O_RDONLY);
return 0;
}
// Daemonize here
if (!nofork) {
daemon(0, 0);
nofork = 1;
}
#endif
// This turns us (the process that calls this ioctl)
// into a dedicated NBD request handler.
// We block here for a long time.
// When exactly ioctl returns? On a signal,
// or if someone does ioctl(NBD_DISCONNECT) [nbd-client -d].
if (ioctl(nbd, NBD_DO_IT) >= 0 || errno == EBADR) {
// Flush queue and exit
ioctl(nbd, NBD_CLEAR_QUEUE);
ioctl(nbd, NBD_CLEAR_SOCK);
break;
}
close(sock);
close(nbd);
} while (opt_p);
return 0;
}