1 /* libguestfs - the guestfsd daemon
2 * Copyright (C) 2009-2010 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>
52 #include "ignore-value.h"
57 static char *read_cmdline (void);
60 # define MAX(a,b) ((a)>(b)?(a):(b))
63 /* Not the end of the world if this open flag is not defined. */
68 /* If root device is an ext2 filesystem, this is the major and minor.
69 * This is so we can ignore this device from the point of view of the
70 * user, eg. in guestfs_list_devices and many other places.
72 static dev_t root_device = 0;
76 static int print_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
77 static int print_sysroot_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
78 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
79 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes, int *size);
81 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
82 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes);
84 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
90 daemon (int nochdir, int noclose)
93 "On Windows the daemon does not support forking into the "
94 "background.\nYou *must* run the daemon with the -f option.\n");
105 /* http://msdn2.microsoft.com/en-us/library/ms742213.aspx */
106 r = gl_sockets_startup (SOCKETS_2_2);
107 return r == 0 ? 0 : -1;
117 /* Location to mount root device. */
118 const char *sysroot = "/sysroot"; /* No trailing slash. */
121 /* Not used explicitly, but required by the gnulib 'error' module. */
122 const char *program_name = "guestfsd";
128 "guestfsd [-f|--foreground] [-v|--verbose]\n");
132 main (int argc, char *argv[])
134 static const char *options = "fv?";
135 static const struct option long_options[] = {
136 { "foreground", 0, 0, 'f' },
137 { "help", 0, 0, '?' },
138 { "verbose", 0, 0, 'v' },
145 if (winsock_init () == -1)
146 error (EXIT_FAILURE, 0, "winsock initialization failed");
148 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
149 /* http://udrepper.livejournal.com/20948.html */
150 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
151 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
153 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
154 register_printf_function ('Q', print_shell_quote, print_arginfo);
155 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
157 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
162 if (stat ("/", &statbuf) == 0)
163 root_device = statbuf.st_dev;
166 c = getopt_long (argc, argv, options, long_options, NULL);
183 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
193 cmdline = read_cmdline ();
195 /* Set the verbose flag. */
197 (cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
199 printf ("verbose daemon enabled\n");
203 printf ("linux commmand line: %s\n", cmdline);
205 printf ("could not read linux command line\n");
209 /* Make sure SIGPIPE doesn't kill us. */
211 memset (&sa, 0, sizeof sa);
212 sa.sa_handler = SIG_IGN;
214 if (sigaction (SIGPIPE, &sa, NULL) == -1)
215 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
219 # define setenv(n,v,f) _putenv(n "=" v)
221 /* Set up a basic environment. After we are called by /init the
222 * environment is essentially empty.
223 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
225 * NOTE: if you change $PATH, you must also change 'prog_exists'
228 setenv ("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
229 setenv ("SHELL", "/bin/sh", 1);
230 setenv ("LC_ALL", "C", 1);
231 setenv ("TERM", "dumb", 1);
234 /* We document that umask defaults to 022 (it should be this anyway). */
237 /* This is the default for Windows anyway. It's not even clear if
238 * Windows ever uses this -- the MSDN documentation for the function
239 * contains obvious errors.
244 /* Connect to virtio-serial channel. */
245 int sock = open ("/dev/virtio-ports/org.libguestfs.channel.0",
250 "Failed to connect to virtio-serial channel.\n"
252 "This is a fatal error and the appliance will now exit.\n"
254 "Usually this error is caused by either QEMU or the appliance\n"
255 "kernel not supporting the vmchannel method that the\n"
256 "libguestfs library chose to use. Please run\n"
257 "'libguestfs-test-tool' and provide the complete, unedited\n"
258 "output to the libguestfs developers, either in a bug report\n"
259 "or on the libguestfs redhat com mailing list.\n"
264 /* Send the magic length message which indicates that
265 * userspace is up inside the guest.
269 uint32_t len = GUESTFS_LAUNCH_FLAG;
270 xdrmem_create (&xdr, lenbuf, sizeof lenbuf, XDR_ENCODE);
271 xdr_u_int (&xdr, &len);
273 if (xwrite (sock, lenbuf, sizeof lenbuf) == -1)
278 /* Fork into the background. */
280 if (daemon (0, 1) == -1) {
286 /* Enter the main loop, reading and performing actions. */
292 /* Read /proc/cmdline. */
296 int fd = open ("/proc/cmdline", O_RDONLY);
298 perror ("/proc/cmdline");
308 n = read (fd, buf, sizeof buf);
317 char *newr = realloc (r, len + n + 1); /* + 1 is for terminating NUL */
325 memcpy (&r[len], buf, n);
332 if (close (fd) == -1) {
341 /* Return true iff device is the root device (and therefore should be
342 * ignored from the point of view of user calls).
345 is_root_device (const char *device)
348 if (stat (device, &statbuf) == -1) {
352 if (statbuf.st_rdev == root_device)
357 /* Turn "/path" into "/sysroot/path".
359 * Caller must check for NULL and call reply_with_perror ("malloc")
360 * if it is. Caller must also free the string.
362 * See also the custom %R printf formatter which does shell quoting too.
365 sysroot_path (const char *path)
368 int len = strlen (path) + sysroot_len + 1;
374 snprintf (r, len, "%s%s", sysroot, path);
379 xwrite (int sock, const void *v_buf, size_t len)
382 const char *buf = v_buf;
385 r = write (sock, buf, len);
398 xread (int sock, void *v_buf, size_t len)
404 r = read (sock, buf, len);
410 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
421 add_string (char ***argv, int *size, int *alloc, const char *str)
426 if (*size >= *alloc) {
428 new_argv = realloc (*argv, *alloc * sizeof (char *));
429 if (new_argv == NULL) {
430 reply_with_perror ("realloc");
431 free_strings (*argv);
438 new_str = strdup (str);
439 if (new_str == NULL) {
440 reply_with_perror ("strdup");
441 free_strings (*argv);
446 (*argv)[*size] = new_str;
453 count_strings (char *const *argv)
457 for (argc = 0; argv[argc] != NULL; ++argc)
462 /* http://graphics.stanford.edu/~seander/bithacks.html#DetermineIfPowerOf2 */
464 is_power_of_2 (unsigned long v)
466 return v && ((v & (v - 1)) == 0);
470 compare (const void *vp1, const void *vp2)
472 char * const *p1 = (char * const *) vp1;
473 char * const *p2 = (char * const *) vp2;
474 return strcmp (*p1, *p2);
478 sort_strings (char **argv, int len)
480 qsort (argv, len, sizeof (char *), compare);
484 free_strings (char **argv)
488 for (argc = 0; argv[argc] != NULL; ++argc)
494 free_stringslen (char **argv, int len)
498 for (i = 0; i < len; ++i)
503 /* Easy ways to run external commands. For full documentation, see
504 * 'commandrvf' below.
507 commandf (char **stdoutput, char **stderror, int flags, const char *name, ...)
514 /* Collect the command line arguments into an array. */
516 argv = malloc (sizeof (char *) * i);
521 argv[0] = (char *) name;
524 va_start (args, name);
526 while ((s = va_arg (args, char *)) != NULL) {
527 const char **p = realloc (argv, sizeof (char *) * (++i));
541 r = commandvf (stdoutput, stderror, flags, (const char * const*) argv);
543 /* NB: Mustn't free the strings which are on the stack. */
549 /* Same as 'command', but we allow the status code from the
550 * subcommand to be non-zero, and return that status code.
551 * We still return -1 if there was some other error.
554 commandrf (char **stdoutput, char **stderror, int flags, const char *name, ...)
561 /* Collect the command line arguments into an array. */
563 argv = malloc (sizeof (char *) * i);
568 argv[0] = (char *) name;
571 va_start (args, name);
573 while ((s = va_arg (args, char *)) != NULL) {
574 const char **p = realloc (argv, sizeof (char *) * (++i));
588 r = commandrvf (stdoutput, stderror, flags, argv);
590 /* NB: Mustn't free the strings which are on the stack. */
596 /* Same as 'command', but passing an argv. */
598 commandvf (char **stdoutput, char **stderror, int flags,
599 char const *const *argv)
603 r = commandrvf (stdoutput, stderror, flags, (void *) argv);
610 /* This is a more sane version of 'system(3)' for running external
611 * commands. It uses fork/execvp, so we don't need to worry about
612 * quoting of parameters, and it allows us to capture any error
613 * messages in a buffer.
615 * If stdoutput is not NULL, then *stdoutput will return the stdout
618 * If stderror is not NULL, then *stderror will return the stderr
619 * of the command. If there is a final \n character, it is removed
620 * so you can use the error string directly in a call to
625 * COMMAND_FLAG_FOLD_STDOUT_ON_STDERR: For broken external commands
626 * that send error messages to stdout (hello, parted) but that don't
627 * have any useful stdout information, use this flag to capture the
628 * error messages in the *stderror buffer. If using this flag,
629 * you should pass stdoutput as NULL because nothing could ever be
630 * captured in that buffer.
632 * COMMAND_FLAG_CHROOT_COPY_FILE_TO_STDIN: For running external
633 * commands on chrooted files correctly (see RHBZ#579608) specifying
634 * this flag causes another process to be forked which chroots into
635 * sysroot and just copies the input file to stdin of the specified
636 * command. The file descriptor is ORed with the flags, and that file
637 * descriptor is always closed by this function. See hexdump.c for an
641 commandrvf (char **stdoutput, char **stderror, int flags,
642 char const* const *argv)
644 int so_size = 0, se_size = 0;
645 int so_fd[2], se_fd[2];
646 int flag_copy_stdin = flags & COMMAND_FLAG_CHROOT_COPY_FILE_TO_STDIN;
647 int stdin_fd[2] = { -1, -1 };
648 pid_t pid, stdin_pid = -1;
654 if (stdoutput) *stdoutput = NULL;
655 if (stderror) *stderror = NULL;
658 printf ("%s", argv[0]);
659 for (i = 1; argv[i] != NULL; ++i)
660 printf (" %s", argv[i]);
664 /* Note: abort is used in a few places along the error paths early
665 * in this function. This is because (a) cleaning up correctly is
666 * very complex at these places and (b) abort is used when a
667 * resource problems is indicated which would be due to much more
668 * serious issues - eg. memory or file descriptor leaks. We
669 * wouldn't expect fork(2) or pipe(2) to fail in normal
673 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
674 error (0, errno, "pipe");
678 if (flag_copy_stdin) {
679 if (pipe (stdin_fd) == -1) {
680 error (0, errno, "pipe");
687 error (0, errno, "fork");
691 if (pid == 0) { /* Child process running the command. */
693 if (flag_copy_stdin) {
694 dup2 (stdin_fd[0], 0);
698 /* Set stdin to /dev/null (ignore failure) */
699 open ("/dev/null", O_RDONLY);
703 if (!(flags & COMMAND_FLAG_FOLD_STDOUT_ON_STDERR))
711 execvp (argv[0], (void *) argv);
713 _exit (EXIT_FAILURE);
716 if (flag_copy_stdin) {
717 int fd = flags & COMMAND_FLAG_FD_MASK;
720 if (stdin_pid == -1) {
721 error (0, errno, "fork");
725 if (stdin_pid == 0) { /* Child process copying stdin. */
732 dup2 (stdin_fd[1], 1);
736 if (chroot (sysroot) == -1) {
738 _exit (EXIT_FAILURE);
743 while ((n = read (fd, buffer, sizeof buffer)) > 0) {
744 if (xwrite (1, buffer, n) == -1)
745 /* EPIPE error indicates the command process has exited
746 * early. If the command process fails that will be caught
747 * by the daemon, and if not, then it's not an error.
749 _exit (errno == EPIPE ? EXIT_SUCCESS : EXIT_FAILURE);
754 _exit (EXIT_FAILURE);
757 if (close (fd) == -1) {
759 _exit (EXIT_FAILURE);
762 _exit (EXIT_SUCCESS);
770 /* Parent process. */
775 FD_SET (so_fd[0], &rset);
776 FD_SET (se_fd[0], &rset);
781 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
785 if (stdoutput) free (*stdoutput);
786 if (stderror) free (*stderror);
789 waitpid (pid, NULL, 0);
790 if (stdin_pid >= 0) waitpid (stdin_pid, NULL, 0);
794 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
795 r = read (so_fd[0], buf, sizeof buf);
800 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
802 if (r > 0 && stdoutput) {
804 p = realloc (*stdoutput, so_size);
810 memcpy (*stdoutput + so_size - r, buf, r);
814 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
815 r = read (se_fd[0], buf, sizeof buf);
820 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
824 ignore_value (write (2, buf, r));
828 p = realloc (*stderror, se_size);
834 memcpy (*stderror + se_size - r, buf, r);
843 /* Make sure the output buffers are \0-terminated. Also remove any
844 * trailing \n characters from the error buffer (not from stdout).
847 void *q = realloc (*stdoutput, so_size+1);
854 (*stdoutput)[so_size] = '\0';
857 void *q = realloc (*stderror, se_size+1);
864 (*stderror)[se_size] = '\0';
866 while (se_size >= 0 && (*stderror)[se_size] == '\n')
867 (*stderror)[se_size--] = '\0';
871 if (flag_copy_stdin) {
872 /* Check copy process didn't fail. */
873 if (waitpid (stdin_pid, &r, 0) != stdin_pid) {
876 waitpid (pid, NULL, 0);
880 if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) {
881 fprintf (stderr, "failed copying from input file, see earlier messages\n");
883 waitpid (pid, NULL, 0);
888 /* Get the exit status of the command. */
889 if (waitpid (pid, &r, 0) != pid) {
895 return WEXITSTATUS (r);
900 /* Split an output string into a NULL-terminated list of lines.
901 * Typically this is used where we have run an external command
902 * which has printed out a list of things, and we want to return
905 * The corner cases here are quite tricky. Note in particular:
909 * "a\nb" -> ["a"; "b"]
910 * "a\nb\n" -> ["a"; "b"]
911 * "a\nb\n\n" -> ["a"; "b"; ""]
913 * The original string is written over and destroyed by this
914 * function (which is usually OK because it's the 'out' string
915 * from command()). You can free the original string, because
916 * add_string() strdups the strings.
919 split_lines (char *str)
922 int size = 0, alloc = 0;
930 /* Empty last line? */
934 pend = strchr (p, '\n');
940 if (add_string (&lines, &size, &alloc, p) == -1) {
948 if (add_string (&lines, &size, &alloc, NULL) == -1)
954 /* Skip leading and trailing whitespace, updating the original string
960 size_t len = strlen (str);
962 while (len > 0 && c_isspace (str[len-1])) {
968 while (*p && c_isspace (*p)) {
973 memmove (str, p, len+1);
976 /* printf helper function so we can use %Q ("quoted") and %R to print
977 * shell-quoted strings. See HACKING file for more details.
980 print_shell_quote (FILE *stream,
981 const struct printf_info *info ATTRIBUTE_UNUSED,
982 const void *const *args)
984 #define SAFE(c) (c_isalnum((c)) || \
985 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
987 const char *str = *((const char **) (args[0]));
989 for (i = len = 0; str[i]; ++i) {
994 putc (str[i], stream);
1002 print_sysroot_shell_quote (FILE *stream,
1003 const struct printf_info *info,
1004 const void *const *args)
1006 fputs (sysroot, stream);
1007 return sysroot_len + print_shell_quote (stream, info, args);
1010 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
1012 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
1013 size_t n, int *argtypes, int *size)
1016 argtypes[0] = PA_STRING;
1017 size[0] = sizeof (const char *);
1022 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
1024 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
1027 argtypes[0] = PA_STRING;
1031 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
1035 /* Perform device name translation. Don't call this directly -
1036 * use the RESOLVE_DEVICE macro.
1038 * See guestfs(3) for the algorithm.
1040 * We have to open the device and test for ENXIO, because
1041 * the device nodes themselves will exist in the appliance.
1044 device_name_translation (char *device)
1048 fd = open (device, O_RDONLY);
1055 if (errno != ENXIO && errno != ENOENT)
1058 /* If the name begins with "/dev/sd" then try the alternatives. */
1059 if (STRNEQLEN (device, "/dev/sd", 7))
1062 device[5] = 'h'; /* /dev/hd (old IDE driver) */
1063 fd = open (device, O_RDONLY);
1067 device[5] = 'v'; /* /dev/vd (for virtio devices) */
1068 fd = open (device, O_RDONLY);
1072 device[5] = 's'; /* Restore original device name. */
1076 /* Check program exists and is executable on $PATH. Actually, we
1077 * just assume PATH contains the default entries (see main() above).
1080 prog_exists (const char *prog)
1082 static const char * const dirs[] =
1083 { "/sbin", "/usr/sbin", "/bin", "/usr/bin" };
1087 for (i = 0; i < sizeof dirs / sizeof dirs[0]; ++i) {
1088 snprintf (buf, sizeof buf, "%s/%s", dirs[i], prog);
1089 if (access (buf, X_OK) == 0)
1095 /* LVM and other commands aren't synchronous, especially when udev is
1096 * involved. eg. You can create or remove some device, but the /dev
1097 * device node won't appear until some time later. This means that
1098 * you get an error if you run one command followed by another.
1100 * Use 'udevadm settle' after certain commands, but don't be too
1101 * fussed if it fails.
1103 * 'udevsettle' was the old name for this command (RHEL 5). This was
1104 * deprecated in favour of 'udevadm settle'. The old 'udevsettle'
1105 * command was left as a symlink. Then in Fedora 13 the old symlink
1106 * remained but it stopped working (RHBZ#548121), so we have to be
1107 * careful not to assume that we can use 'udevsettle' if it exists.
1112 (void) command (NULL, NULL, "udevadm", "settle", NULL);
1113 (void) command (NULL, NULL, "udevsettle", NULL);