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>
48 #include "ignore-value.h"
52 static char *read_cmdline (void);
54 /* Also in guestfs.c */
55 #define GUESTFWD_ADDR "10.0.2.4"
56 #define GUESTFWD_PORT "6666"
58 /* This is only a hint. If not defined, ignore it. */
60 #define AI_ADDRCONFIG 0
65 static int print_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
66 static int print_sysroot_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
67 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
68 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes, int *size);
70 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
71 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes);
73 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
77 /* Location to mount root device. */
78 const char *sysroot = "/sysroot"; /* No trailing slash. */
85 "guestfsd [-f|--foreground] [-c|--channel vmchannel] [-v|--verbose]\n");
89 main (int argc, char *argv[])
91 static const char *options = "fc:v?";
92 static const struct option long_options[] = {
93 { "channel", required_argument, 0, 'c' },
94 { "foreground", 0, 0, 'f' },
95 { "help", 0, 0, '?' },
96 { "verbose", 0, 0, 'v' },
102 char *vmchannel = NULL;
104 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
105 /* http://udrepper.livejournal.com/20948.html */
106 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
107 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
109 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
110 register_printf_function ('Q', print_shell_quote, print_arginfo);
111 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
113 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
118 c = getopt_long (argc, argv, options, long_options, NULL);
139 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
149 cmdline = read_cmdline ();
151 /* Set the verbose flag. */
153 (cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
155 printf ("verbose daemon enabled\n");
159 printf ("linux commmand line: %s\n", cmdline);
161 printf ("could not read linux command line\n");
165 /* Make sure SIGPIPE doesn't kill us. */
167 memset (&sa, 0, sizeof sa);
168 sa.sa_handler = SIG_IGN;
170 if (sigaction (SIGPIPE, &sa, NULL) == -1)
171 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
175 #define setenv(n,v,f) _putenv(n "=" v)
177 /* Set up a basic environment. After we are called by /init the
178 * environment is essentially empty.
179 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
181 setenv ("PATH", "/usr/bin:/bin", 1);
182 setenv ("SHELL", "/bin/sh", 1);
183 setenv ("LC_ALL", "C", 1);
186 /* We document that umask defaults to 022 (it should be this anyway). */
189 /* This is the default for Windows anyway. It's not even clear if
190 * Windows ever uses this -- the MSDN documentation for the function
191 * contains obvious errors.
196 /* Get the vmchannel string.
199 * --channel/-c option on the command line
200 * guestfs_vmchannel=... from the kernel command line
201 * guestfs=... from the kernel command line
204 * At the moment we expect this to contain "tcp:ip:port" but in
205 * future it might contain a device name, eg. "/dev/vcon4" for
206 * virtio-console vmchannel.
208 if (vmchannel == NULL && cmdline) {
212 p = strstr (cmdline, "guestfs_vmchannel=");
214 len = strcspn (p + 18, " \t\n");
215 vmchannel = strndup (p + 18, len);
222 /* Old libraries passed guestfs=host:port. Rewrite it as tcp:host:port. */
223 if (vmchannel == NULL) {
224 /* We will rewrite it part of the "guestfs=" string with
225 * "tcp:" hence p + 4 below. */
226 p = strstr (cmdline, "guestfs=");
228 len = strcspn (p + 4, " \t\n");
229 vmchannel = strndup (p + 4, len);
234 memcpy (vmchannel, "tcp:", 4);
239 /* Default vmchannel. */
240 if (vmchannel == NULL) {
241 vmchannel = strdup ("tcp:" GUESTFWD_ADDR ":" GUESTFWD_PORT);
249 printf ("vmchannel: %s\n", vmchannel);
251 /* Connect to vmchannel. */
254 if (STREQLEN (vmchannel, "tcp:", 4)) {
255 /* Resolve the hostname. */
256 struct addrinfo *res, *rr;
257 struct addrinfo hints;
262 port = strchr (host, ':');
267 fprintf (stderr, "vmchannel: expecting \"tcp:<ip>:<port>\": %s\n",
272 memset (&hints, 0, sizeof hints);
273 hints.ai_socktype = SOCK_STREAM;
274 hints.ai_flags = AI_ADDRCONFIG;
275 r = getaddrinfo (host, port, &hints, &res);
277 fprintf (stderr, "%s:%s: %s\n",
278 host, port, gai_strerror (r));
282 /* Connect to the given TCP socket. */
283 for (rr = res; rr != NULL; rr = rr->ai_next) {
284 sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
286 if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
297 "unknown vmchannel connection type: %s\n"
298 "expecting \"tcp:<ip>:<port>\"\n",
306 "Failed to connect to any vmchannel implementation.\n"
309 "This is a fatal error and the appliance will now exit.\n"
311 "Usually this error is caused by either QEMU or the appliance\n"
312 "kernel not supporting the vmchannel method that the\n"
313 "libguestfs library chose to use. Please run\n"
314 "'libguestfs-test-tool' and provide the complete, unedited\n"
315 "output to the libguestfs developers, either in a bug report\n"
316 "or on the libguestfs redhat com mailing list.\n"
322 /* Send the magic length message which indicates that
323 * userspace is up inside the guest.
327 uint32_t len = GUESTFS_LAUNCH_FLAG;
328 xdrmem_create (&xdr, lenbuf, sizeof lenbuf, XDR_ENCODE);
329 xdr_u_int (&xdr, &len);
331 if (xwrite (sock, lenbuf, sizeof lenbuf) == -1)
336 /* Fork into the background. */
338 if (daemon (0, 1) == -1) {
344 /* Enter the main loop, reading and performing actions. */
350 /* Read /proc/cmdline. */
354 int fd = open ("/proc/cmdline", O_RDONLY);
356 perror ("/proc/cmdline");
366 n = read (fd, buf, sizeof buf);
375 char *newr = realloc (r, len + n + 1); /* + 1 is for terminating NUL */
383 memcpy (&r[len], buf, n);
390 if (close (fd) == -1) {
399 /* Turn "/path" into "/sysroot/path".
401 * Caller must check for NULL and call reply_with_perror ("malloc")
402 * if it is. Caller must also free the string.
404 * See also the custom %R printf formatter which does shell quoting too.
407 sysroot_path (const char *path)
410 int len = strlen (path) + sysroot_len + 1;
416 snprintf (r, len, "%s%s", sysroot, path);
421 xwrite (int sock, const void *v_buf, size_t len)
424 const char *buf = v_buf;
427 r = write (sock, buf, len);
440 xread (int sock, void *v_buf, size_t len)
446 r = read (sock, buf, len);
452 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
463 add_string (char ***argv, int *size, int *alloc, const char *str)
468 if (*size >= *alloc) {
470 new_argv = realloc (*argv, *alloc * sizeof (char *));
471 if (new_argv == NULL) {
472 reply_with_perror ("realloc");
473 free_strings (*argv);
480 new_str = strdup (str);
481 if (new_str == NULL) {
482 reply_with_perror ("strdup");
483 free_strings (*argv);
488 (*argv)[*size] = new_str;
495 count_strings (char *const *argv)
499 for (argc = 0; argv[argc] != NULL; ++argc)
505 compare (const void *vp1, const void *vp2)
507 char * const *p1 = (char * const *) vp1;
508 char * const *p2 = (char * const *) vp2;
509 return strcmp (*p1, *p2);
513 sort_strings (char **argv, int len)
515 qsort (argv, len, sizeof (char *), compare);
519 free_strings (char **argv)
523 for (argc = 0; argv[argc] != NULL; ++argc)
529 free_stringslen (char **argv, int len)
533 for (i = 0; i < len; ++i)
538 /* Easy ways to run external commands. For full documentation, see
539 * 'commandrvf' below.
542 commandf (char **stdoutput, char **stderror, int flags, const char *name, ...)
549 /* Collect the command line arguments into an array. */
551 argv = malloc (sizeof (char *) * i);
556 argv[0] = (char *) name;
559 va_start (args, name);
561 while ((s = va_arg (args, char *)) != NULL) {
562 const char **p = realloc (argv, sizeof (char *) * (++i));
576 r = commandvf (stdoutput, stderror, flags, (const char * const*) argv);
578 /* NB: Mustn't free the strings which are on the stack. */
584 /* Same as 'command', but we allow the status code from the
585 * subcommand to be non-zero, and return that status code.
586 * We still return -1 if there was some other error.
589 commandrf (char **stdoutput, char **stderror, int flags, const char *name, ...)
596 /* Collect the command line arguments into an array. */
598 argv = malloc (sizeof (char *) * i);
603 argv[0] = (char *) name;
606 va_start (args, name);
608 while ((s = va_arg (args, char *)) != NULL) {
609 const char **p = realloc (argv, sizeof (char *) * (++i));
623 r = commandrvf (stdoutput, stderror, flags, argv);
625 /* NB: Mustn't free the strings which are on the stack. */
631 /* Same as 'command', but passing an argv. */
633 commandvf (char **stdoutput, char **stderror, int flags,
634 char const *const *argv)
638 r = commandrvf (stdoutput, stderror, flags, (void *) argv);
645 /* This is a more sane version of 'system(3)' for running external
646 * commands. It uses fork/execvp, so we don't need to worry about
647 * quoting of parameters, and it allows us to capture any error
648 * messages in a buffer.
650 * If stdoutput is not NULL, then *stdoutput will return the stdout
653 * If stderror is not NULL, then *stderror will return the stderr
654 * of the command. If there is a final \n character, it is removed
655 * so you can use the error string directly in a call to
660 * COMMAND_FLAG_FOLD_STDOUT_ON_STDERR: For broken external commands
661 * that send error messages to stdout (hello, parted) but that don't
662 * have any useful stdout information, use this flag to capture the
663 * error messages in the *stderror buffer. If using this flag,
664 * you should pass stdoutput as NULL because nothing could ever be
665 * captured in that buffer.
668 commandrvf (char **stdoutput, char **stderror, int flags,
669 char const* const *argv)
671 int so_size = 0, se_size = 0;
672 int so_fd[2], se_fd[2];
679 if (stdoutput) *stdoutput = NULL;
680 if (stderror) *stderror = NULL;
683 printf ("%s", argv[0]);
684 for (i = 1; argv[i] != NULL; ++i)
685 printf (" %s", argv[i]);
689 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
704 if (pid == 0) { /* Child process. */
706 open ("/dev/null", O_RDONLY); /* Set stdin to /dev/null (ignore failure) */
709 if (!(flags & COMMAND_FLAG_FOLD_STDOUT_ON_STDERR))
717 execvp (argv[0], (void *) argv);
722 /* Parent process. */
727 FD_SET (so_fd[0], &rset);
728 FD_SET (se_fd[0], &rset);
733 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
737 if (stdoutput) free (*stdoutput);
738 if (stderror) free (*stderror);
741 waitpid (pid, NULL, 0);
745 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
746 r = read (so_fd[0], buf, sizeof buf);
751 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
753 if (r > 0 && stdoutput) {
755 p = realloc (*stdoutput, so_size);
761 memcpy (*stdoutput + so_size - r, buf, r);
765 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
766 r = read (se_fd[0], buf, sizeof buf);
771 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
775 ignore_value (write (2, buf, r));
779 p = realloc (*stderror, se_size);
785 memcpy (*stderror + se_size - r, buf, r);
794 /* Make sure the output buffers are \0-terminated. Also remove any
795 * trailing \n characters from the error buffer (not from stdout).
798 void *q = realloc (*stdoutput, so_size+1);
805 (*stdoutput)[so_size] = '\0';
808 void *q = realloc (*stderror, se_size+1);
815 (*stderror)[se_size] = '\0';
817 while (se_size >= 0 && (*stderror)[se_size] == '\n')
818 (*stderror)[se_size--] = '\0';
822 /* Get the exit status of the command. */
823 if (waitpid (pid, &r, 0) != pid) {
829 return WEXITSTATUS (r);
834 /* Split an output string into a NULL-terminated list of lines.
835 * Typically this is used where we have run an external command
836 * which has printed out a list of things, and we want to return
839 * The corner cases here are quite tricky. Note in particular:
843 * "a\nb" -> ["a"; "b"]
844 * "a\nb\n" -> ["a"; "b"]
845 * "a\nb\n\n" -> ["a"; "b"; ""]
847 * The original string is written over and destroyed by this
848 * function (which is usually OK because it's the 'out' string
849 * from command()). You can free the original string, because
850 * add_string() strdups the strings.
853 split_lines (char *str)
856 int size = 0, alloc = 0;
864 /* Empty last line? */
868 pend = strchr (p, '\n');
874 if (add_string (&lines, &size, &alloc, p) == -1) {
882 if (add_string (&lines, &size, &alloc, NULL) == -1)
888 /* printf helper function so we can use %Q ("quoted") and %R to print
889 * shell-quoted strings. See HACKING file for more details.
892 print_shell_quote (FILE *stream,
893 const struct printf_info *info ATTRIBUTE_UNUSED,
894 const void *const *args)
896 #define SAFE(c) (c_isalnum((c)) || \
897 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
899 const char *str = *((const char **) (args[0]));
901 for (i = len = 0; str[i]; ++i) {
906 putc (str[i], stream);
914 print_sysroot_shell_quote (FILE *stream,
915 const struct printf_info *info,
916 const void *const *args)
918 fputs (sysroot, stream);
919 return sysroot_len + print_shell_quote (stream, info, args);
922 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
924 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
925 size_t n, int *argtypes, int *size)
928 argtypes[0] = PA_STRING;
929 size[0] = sizeof (const char *);
934 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
936 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
939 argtypes[0] = PA_STRING;
943 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
947 /* Perform device name translation. Don't call this directly -
948 * use the RESOLVE_DEVICE macro.
950 * See guestfs(3) for the algorithm.
952 * We have to open the device and test for ENXIO, because
953 * the device nodes themselves will exist in the appliance.
956 device_name_translation (char *device, const char *func)
960 fd = open (device, O_RDONLY);
966 if (errno != ENXIO && errno != ENOENT) {
968 reply_with_perror ("%s: %s", func, device);
972 /* If the name begins with "/dev/sd" then try the alternatives. */
973 if (STRNEQLEN (device, "/dev/sd", 7))
976 device[5] = 'h'; /* /dev/hd (old IDE driver) */
977 fd = open (device, O_RDONLY);
983 device[5] = 'v'; /* /dev/vd (for virtio devices) */
984 fd = open (device, O_RDONLY);
990 device[5] = 's'; /* Restore original device name. */
994 /* LVM and other commands aren't synchronous, especially when udev is
995 * involved. eg. You can create or remove some device, but the /dev
996 * device node won't appear until some time later. This means that
997 * you get an error if you run one command followed by another.
998 * Use 'udevadm settle' after certain commands, but don't be too
999 * fussed if it fails.
1004 static int which_prog = 0;
1006 if (which_prog == 0) {
1007 if (access ("/sbin/udevsettle", X_OK) == 0)
1009 else if (access ("/sbin/udevadm", X_OK) == 0)
1015 switch (which_prog) {
1017 command (NULL, NULL, "/sbin/udevadm", "settle", NULL);
1020 command (NULL, NULL, "/sbin/udevsettle", NULL);