1 /* libguestfs - the guestfsd daemon
2 * Copyright (C) 2009 Red Hat Inc.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 #define _BSD_SOURCE /* for daemon(3) */
31 #include <rpc/types.h>
34 #include <sys/param.h>
35 #include <sys/types.h>
40 #include <sys/select.h>
42 #include <arpa/inet.h>
43 #include <netinet/in.h>
51 #include "ignore-value.h"
56 static char *read_cmdline (void);
58 /* This is the default address we connect to for very old libraries
59 * which didn't specify the address and port number explicitly on the
60 * kernel command line. It's now recommended to always specify the
61 * address and port number on the command line, so this will not be
64 #define OLD_GUESTFWD_ADDR "10.0.2.4"
65 #define OLD_GUESTFWD_PORT "6666"
67 /* This is only a hint. If not defined, ignore it. */
69 # define AI_ADDRCONFIG 0
73 # define MAX(a,b) ((a)>(b)?(a):(b))
78 static int print_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
79 static int print_sysroot_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
80 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
81 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes, int *size);
83 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
84 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes);
86 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
92 daemon (int nochdir, int noclose)
95 "On Windows the daemon does not support forking into the "
96 "background.\nYou *must* run the daemon with the -f option.\n");
107 /* http://msdn2.microsoft.com/en-us/library/ms742213.aspx */
108 r = gl_sockets_startup (SOCKETS_2_2);
109 return r == 0 ? 0 : -1;
119 /* Location to mount root device. */
120 const char *sysroot = "/sysroot"; /* No trailing slash. */
123 /* Not used explicitly, but required by the gnulib 'error' module. */
124 const char *program_name = "guestfsd";
130 "guestfsd [-f|--foreground] [-c|--channel vmchannel] [-v|--verbose]\n");
134 main (int argc, char *argv[])
136 static const char *options = "fc:v?";
137 static const struct option long_options[] = {
138 { "channel", required_argument, 0, 'c' },
139 { "foreground", 0, 0, 'f' },
140 { "help", 0, 0, '?' },
141 { "verbose", 0, 0, 'v' },
147 char *vmchannel = NULL;
149 if (winsock_init () == -1)
150 error (EXIT_FAILURE, 0, "winsock initialization failed");
152 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
153 /* http://udrepper.livejournal.com/20948.html */
154 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
155 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
157 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
158 register_printf_function ('Q', print_shell_quote, print_arginfo);
159 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
161 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
166 c = getopt_long (argc, argv, options, long_options, NULL);
187 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
197 cmdline = read_cmdline ();
199 /* Set the verbose flag. */
201 (cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
203 printf ("verbose daemon enabled\n");
207 printf ("linux commmand line: %s\n", cmdline);
209 printf ("could not read linux command line\n");
213 /* Make sure SIGPIPE doesn't kill us. */
215 memset (&sa, 0, sizeof sa);
216 sa.sa_handler = SIG_IGN;
218 if (sigaction (SIGPIPE, &sa, NULL) == -1)
219 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
223 # define setenv(n,v,f) _putenv(n "=" v)
225 /* Set up a basic environment. After we are called by /init the
226 * environment is essentially empty.
227 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
229 * NOTE: if you change $PATH, you must also change 'prog_exists'
232 setenv ("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
233 setenv ("SHELL", "/bin/sh", 1);
234 setenv ("LC_ALL", "C", 1);
235 setenv ("TERM", "dumb", 1);
238 /* We document that umask defaults to 022 (it should be this anyway). */
241 /* This is the default for Windows anyway. It's not even clear if
242 * Windows ever uses this -- the MSDN documentation for the function
243 * contains obvious errors.
248 /* Get the vmchannel string.
251 * --channel/-c option on the command line
252 * guestfs_vmchannel=... from the kernel command line
253 * guestfs=... from the kernel command line
256 * At the moment we expect this to contain "tcp:ip:port" but in
257 * future it might contain a device name, eg. "/dev/vcon4" for
258 * virtio-console vmchannel.
260 if (vmchannel == NULL && cmdline) {
264 p = strstr (cmdline, "guestfs_vmchannel=");
266 len = strcspn (p + 18, " \t\n");
267 vmchannel = strndup (p + 18, len);
274 /* Old libraries passed guestfs=host:port. Rewrite it as tcp:host:port. */
275 if (vmchannel == NULL) {
276 /* We will rewrite it part of the "guestfs=" string with
277 * "tcp:" hence p + 4 below. */
278 p = strstr (cmdline, "guestfs=");
280 len = strcspn (p + 4, " \t\n");
281 vmchannel = strndup (p + 4, len);
286 memcpy (vmchannel, "tcp:", 4);
291 /* Default vmchannel. */
292 if (vmchannel == NULL) {
293 vmchannel = strdup ("tcp:" OLD_GUESTFWD_ADDR ":" OLD_GUESTFWD_PORT);
301 printf ("vmchannel: %s\n", vmchannel);
303 /* Connect to vmchannel. */
306 if (STREQLEN (vmchannel, "tcp:", 4)) {
307 /* Resolve the hostname. */
308 struct addrinfo *res, *rr;
309 struct addrinfo hints;
314 port = strchr (host, ':');
319 fprintf (stderr, "vmchannel: expecting \"tcp:<ip>:<port>\": %s\n",
324 memset (&hints, 0, sizeof hints);
325 hints.ai_socktype = SOCK_STREAM;
326 hints.ai_flags = AI_ADDRCONFIG;
327 r = getaddrinfo (host, port, &hints, &res);
329 fprintf (stderr, "%s:%s: %s\n",
330 host, port, gai_strerror (r));
334 /* Connect to the given TCP socket. */
335 for (rr = res; rr != NULL; rr = rr->ai_next) {
336 sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
338 if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
349 "unknown vmchannel connection type: %s\n"
350 "expecting \"tcp:<ip>:<port>\"\n",
358 "Failed to connect to any vmchannel implementation.\n"
361 "This is a fatal error and the appliance will now exit.\n"
363 "Usually this error is caused by either QEMU or the appliance\n"
364 "kernel not supporting the vmchannel method that the\n"
365 "libguestfs library chose to use. Please run\n"
366 "'libguestfs-test-tool' and provide the complete, unedited\n"
367 "output to the libguestfs developers, either in a bug report\n"
368 "or on the libguestfs redhat com mailing list.\n"
374 /* Send the magic length message which indicates that
375 * userspace is up inside the guest.
379 uint32_t len = GUESTFS_LAUNCH_FLAG;
380 xdrmem_create (&xdr, lenbuf, sizeof lenbuf, XDR_ENCODE);
381 xdr_u_int (&xdr, &len);
383 if (xwrite (sock, lenbuf, sizeof lenbuf) == -1)
388 /* Fork into the background. */
390 if (daemon (0, 1) == -1) {
396 /* Enter the main loop, reading and performing actions. */
402 /* Read /proc/cmdline. */
406 int fd = open ("/proc/cmdline", O_RDONLY);
408 perror ("/proc/cmdline");
418 n = read (fd, buf, sizeof buf);
427 char *newr = realloc (r, len + n + 1); /* + 1 is for terminating NUL */
435 memcpy (&r[len], buf, n);
442 if (close (fd) == -1) {
451 /* Turn "/path" into "/sysroot/path".
453 * Caller must check for NULL and call reply_with_perror ("malloc")
454 * if it is. Caller must also free the string.
456 * See also the custom %R printf formatter which does shell quoting too.
459 sysroot_path (const char *path)
462 int len = strlen (path) + sysroot_len + 1;
468 snprintf (r, len, "%s%s", sysroot, path);
473 xwrite (int sock, const void *v_buf, size_t len)
476 const char *buf = v_buf;
479 r = write (sock, buf, len);
492 xread (int sock, void *v_buf, size_t len)
498 r = read (sock, buf, len);
504 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
515 add_string (char ***argv, int *size, int *alloc, const char *str)
520 if (*size >= *alloc) {
522 new_argv = realloc (*argv, *alloc * sizeof (char *));
523 if (new_argv == NULL) {
524 reply_with_perror ("realloc");
525 free_strings (*argv);
532 new_str = strdup (str);
533 if (new_str == NULL) {
534 reply_with_perror ("strdup");
535 free_strings (*argv);
540 (*argv)[*size] = new_str;
547 count_strings (char *const *argv)
551 for (argc = 0; argv[argc] != NULL; ++argc)
557 compare (const void *vp1, const void *vp2)
559 char * const *p1 = (char * const *) vp1;
560 char * const *p2 = (char * const *) vp2;
561 return strcmp (*p1, *p2);
565 sort_strings (char **argv, int len)
567 qsort (argv, len, sizeof (char *), compare);
571 free_strings (char **argv)
575 for (argc = 0; argv[argc] != NULL; ++argc)
581 free_stringslen (char **argv, int len)
585 for (i = 0; i < len; ++i)
590 /* Easy ways to run external commands. For full documentation, see
591 * 'commandrvf' below.
594 commandf (char **stdoutput, char **stderror, int flags, const char *name, ...)
601 /* Collect the command line arguments into an array. */
603 argv = malloc (sizeof (char *) * i);
608 argv[0] = (char *) name;
611 va_start (args, name);
613 while ((s = va_arg (args, char *)) != NULL) {
614 const char **p = realloc (argv, sizeof (char *) * (++i));
628 r = commandvf (stdoutput, stderror, flags, (const char * const*) argv);
630 /* NB: Mustn't free the strings which are on the stack. */
636 /* Same as 'command', but we allow the status code from the
637 * subcommand to be non-zero, and return that status code.
638 * We still return -1 if there was some other error.
641 commandrf (char **stdoutput, char **stderror, int flags, const char *name, ...)
648 /* Collect the command line arguments into an array. */
650 argv = malloc (sizeof (char *) * i);
655 argv[0] = (char *) name;
658 va_start (args, name);
660 while ((s = va_arg (args, char *)) != NULL) {
661 const char **p = realloc (argv, sizeof (char *) * (++i));
675 r = commandrvf (stdoutput, stderror, flags, argv);
677 /* NB: Mustn't free the strings which are on the stack. */
683 /* Same as 'command', but passing an argv. */
685 commandvf (char **stdoutput, char **stderror, int flags,
686 char const *const *argv)
690 r = commandrvf (stdoutput, stderror, flags, (void *) argv);
697 /* This is a more sane version of 'system(3)' for running external
698 * commands. It uses fork/execvp, so we don't need to worry about
699 * quoting of parameters, and it allows us to capture any error
700 * messages in a buffer.
702 * If stdoutput is not NULL, then *stdoutput will return the stdout
705 * If stderror is not NULL, then *stderror will return the stderr
706 * of the command. If there is a final \n character, it is removed
707 * so you can use the error string directly in a call to
712 * COMMAND_FLAG_FOLD_STDOUT_ON_STDERR: For broken external commands
713 * that send error messages to stdout (hello, parted) but that don't
714 * have any useful stdout information, use this flag to capture the
715 * error messages in the *stderror buffer. If using this flag,
716 * you should pass stdoutput as NULL because nothing could ever be
717 * captured in that buffer.
720 commandrvf (char **stdoutput, char **stderror, int flags,
721 char const* const *argv)
723 int so_size = 0, se_size = 0;
724 int so_fd[2], se_fd[2];
731 if (stdoutput) *stdoutput = NULL;
732 if (stderror) *stderror = NULL;
735 printf ("%s", argv[0]);
736 for (i = 1; argv[i] != NULL; ++i)
737 printf (" %s", argv[i]);
741 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
756 if (pid == 0) { /* Child process. */
758 open ("/dev/null", O_RDONLY); /* Set stdin to /dev/null (ignore failure) */
761 if (!(flags & COMMAND_FLAG_FOLD_STDOUT_ON_STDERR))
769 execvp (argv[0], (void *) argv);
774 /* Parent process. */
779 FD_SET (so_fd[0], &rset);
780 FD_SET (se_fd[0], &rset);
785 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
789 if (stdoutput) free (*stdoutput);
790 if (stderror) free (*stderror);
793 waitpid (pid, NULL, 0);
797 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
798 r = read (so_fd[0], buf, sizeof buf);
803 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
805 if (r > 0 && stdoutput) {
807 p = realloc (*stdoutput, so_size);
813 memcpy (*stdoutput + so_size - r, buf, r);
817 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
818 r = read (se_fd[0], buf, sizeof buf);
823 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
827 ignore_value (write (2, buf, r));
831 p = realloc (*stderror, se_size);
837 memcpy (*stderror + se_size - r, buf, r);
846 /* Make sure the output buffers are \0-terminated. Also remove any
847 * trailing \n characters from the error buffer (not from stdout).
850 void *q = realloc (*stdoutput, so_size+1);
857 (*stdoutput)[so_size] = '\0';
860 void *q = realloc (*stderror, se_size+1);
867 (*stderror)[se_size] = '\0';
869 while (se_size >= 0 && (*stderror)[se_size] == '\n')
870 (*stderror)[se_size--] = '\0';
874 /* Get the exit status of the command. */
875 if (waitpid (pid, &r, 0) != pid) {
881 return WEXITSTATUS (r);
886 /* Split an output string into a NULL-terminated list of lines.
887 * Typically this is used where we have run an external command
888 * which has printed out a list of things, and we want to return
891 * The corner cases here are quite tricky. Note in particular:
895 * "a\nb" -> ["a"; "b"]
896 * "a\nb\n" -> ["a"; "b"]
897 * "a\nb\n\n" -> ["a"; "b"; ""]
899 * The original string is written over and destroyed by this
900 * function (which is usually OK because it's the 'out' string
901 * from command()). You can free the original string, because
902 * add_string() strdups the strings.
905 split_lines (char *str)
908 int size = 0, alloc = 0;
916 /* Empty last line? */
920 pend = strchr (p, '\n');
926 if (add_string (&lines, &size, &alloc, p) == -1) {
934 if (add_string (&lines, &size, &alloc, NULL) == -1)
940 /* Skip leading and trailing whitespace, updating the original string
946 size_t len = strlen (str);
948 while (len > 0 && c_isspace (str[len-1])) {
954 while (*p && c_isspace (*p)) {
959 memmove (str, p, len+1);
962 /* printf helper function so we can use %Q ("quoted") and %R to print
963 * shell-quoted strings. See HACKING file for more details.
966 print_shell_quote (FILE *stream,
967 const struct printf_info *info ATTRIBUTE_UNUSED,
968 const void *const *args)
970 #define SAFE(c) (c_isalnum((c)) || \
971 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
973 const char *str = *((const char **) (args[0]));
975 for (i = len = 0; str[i]; ++i) {
980 putc (str[i], stream);
988 print_sysroot_shell_quote (FILE *stream,
989 const struct printf_info *info,
990 const void *const *args)
992 fputs (sysroot, stream);
993 return sysroot_len + print_shell_quote (stream, info, args);
996 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
998 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
999 size_t n, int *argtypes, int *size)
1002 argtypes[0] = PA_STRING;
1003 size[0] = sizeof (const char *);
1008 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
1010 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
1013 argtypes[0] = PA_STRING;
1017 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
1021 /* Perform device name translation. Don't call this directly -
1022 * use the RESOLVE_DEVICE macro.
1024 * See guestfs(3) for the algorithm.
1026 * We have to open the device and test for ENXIO, because
1027 * the device nodes themselves will exist in the appliance.
1030 device_name_translation (char *device, const char *func)
1034 fd = open (device, O_RDONLY);
1040 if (errno != ENXIO && errno != ENOENT) {
1042 reply_with_perror ("%s: %s", func, device);
1046 /* If the name begins with "/dev/sd" then try the alternatives. */
1047 if (STRNEQLEN (device, "/dev/sd", 7))
1050 device[5] = 'h'; /* /dev/hd (old IDE driver) */
1051 fd = open (device, O_RDONLY);
1057 device[5] = 'v'; /* /dev/vd (for virtio devices) */
1058 fd = open (device, O_RDONLY);
1064 device[5] = 's'; /* Restore original device name. */
1068 /* Check program exists and is executable on $PATH. Actually, we
1069 * just assume PATH contains the default entries (see main() above).
1072 prog_exists (const char *prog)
1074 static const char * const dirs[] =
1075 { "/sbin", "/usr/sbin", "/bin", "/usr/bin" };
1079 for (i = 0; i < sizeof dirs / sizeof dirs[0]; ++i) {
1080 snprintf (buf, sizeof buf, "%s/%s", dirs[i], prog);
1081 if (access (buf, X_OK) == 0)
1087 /* LVM and other commands aren't synchronous, especially when udev is
1088 * involved. eg. You can create or remove some device, but the /dev
1089 * device node won't appear until some time later. This means that
1090 * you get an error if you run one command followed by another.
1092 * Use 'udevadm settle' after certain commands, but don't be too
1093 * fussed if it fails.
1095 * 'udevsettle' was the old name for this command (RHEL 5). This was
1096 * deprecated in favour of 'udevadm settle'. The old 'udevsettle'
1097 * command was left as a symlink. Then in Fedora 13 the old symlink
1098 * remained but it stopped working (RHBZ#548121), so we have to be
1099 * careful not to assume that we can use 'udevsettle' if it exists.
1104 (void) command (NULL, NULL, "udevadm", "settle", NULL);
1105 (void) command (NULL, NULL, "udevsettle", NULL);