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 ignore_value (chdir ("/"));
147 if (winsock_init () == -1)
148 error (EXIT_FAILURE, 0, "winsock initialization failed");
150 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
151 /* http://udrepper.livejournal.com/20948.html */
152 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
153 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
155 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
156 register_printf_function ('Q', print_shell_quote, print_arginfo);
157 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
159 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
164 if (stat ("/", &statbuf) == 0)
165 root_device = statbuf.st_dev;
168 c = getopt_long (argc, argv, options, long_options, NULL);
185 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
195 cmdline = read_cmdline ();
197 /* Set the verbose flag. */
199 (cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
201 printf ("verbose daemon enabled\n");
205 printf ("linux commmand line: %s\n", cmdline);
207 printf ("could not read linux command line\n");
211 /* Make sure SIGPIPE doesn't kill us. */
213 memset (&sa, 0, sizeof sa);
214 sa.sa_handler = SIG_IGN;
216 if (sigaction (SIGPIPE, &sa, NULL) == -1)
217 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
221 # define setenv(n,v,f) _putenv(n "=" v)
223 /* Set up a basic environment. After we are called by /init the
224 * environment is essentially empty.
225 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
227 * NOTE: if you change $PATH, you must also change 'prog_exists'
230 setenv ("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
231 setenv ("SHELL", "/bin/sh", 1);
232 setenv ("LC_ALL", "C", 1);
233 setenv ("TERM", "dumb", 1);
236 /* We document that umask defaults to 022 (it should be this anyway). */
239 /* This is the default for Windows anyway. It's not even clear if
240 * Windows ever uses this -- the MSDN documentation for the function
241 * contains obvious errors.
246 /* Connect to virtio-serial channel. */
247 int sock = open ("/dev/virtio-ports/org.libguestfs.channel.0",
252 "Failed to connect to virtio-serial channel.\n"
254 "This is a fatal error and the appliance will now exit.\n"
256 "Usually this error is caused by either QEMU or the appliance\n"
257 "kernel not supporting the vmchannel method that the\n"
258 "libguestfs library chose to use. Please run\n"
259 "'libguestfs-test-tool' and provide the complete, unedited\n"
260 "output to the libguestfs developers, either in a bug report\n"
261 "or on the libguestfs redhat com mailing list.\n"
263 perror ("/dev/virtio-ports/org.libguestfs.channel.0");
267 /* Send the magic length message which indicates that
268 * userspace is up inside the guest.
272 uint32_t len = GUESTFS_LAUNCH_FLAG;
273 xdrmem_create (&xdr, lenbuf, sizeof lenbuf, XDR_ENCODE);
274 xdr_u_int (&xdr, &len);
276 if (xwrite (sock, lenbuf, sizeof lenbuf) == -1) {
283 /* Fork into the background. */
285 if (daemon (0, 1) == -1) {
291 /* Enter the main loop, reading and performing actions. */
297 /* Read /proc/cmdline. */
301 int fd = open ("/proc/cmdline", O_RDONLY);
303 perror ("/proc/cmdline");
313 n = read (fd, buf, sizeof buf);
322 char *newr = realloc (r, len + n + 1); /* + 1 is for terminating NUL */
330 memcpy (&r[len], buf, n);
337 if (close (fd) == -1) {
346 /* Return true iff device is the root device (and therefore should be
347 * ignored from the point of view of user calls).
350 is_root_device (const char *device)
353 if (stat (device, &statbuf) == -1) {
357 if (statbuf.st_rdev == root_device)
362 /* Turn "/path" into "/sysroot/path".
364 * Caller must check for NULL and call reply_with_perror ("malloc")
365 * if it is. Caller must also free the string.
367 * See also the custom %R printf formatter which does shell quoting too.
370 sysroot_path (const char *path)
373 int len = strlen (path) + sysroot_len + 1;
379 snprintf (r, len, "%s%s", sysroot, path);
384 xwrite (int sock, const void *v_buf, size_t len)
387 const char *buf = v_buf;
390 r = write (sock, buf, len);
403 xread (int sock, void *v_buf, size_t len)
409 r = read (sock, buf, len);
415 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
426 add_string (char ***argv, int *size, int *alloc, const char *str)
431 if (*size >= *alloc) {
433 new_argv = realloc (*argv, *alloc * sizeof (char *));
434 if (new_argv == NULL) {
435 reply_with_perror ("realloc");
436 free_strings (*argv);
443 new_str = strdup (str);
444 if (new_str == NULL) {
445 reply_with_perror ("strdup");
446 free_strings (*argv);
451 (*argv)[*size] = new_str;
458 count_strings (char *const *argv)
462 for (argc = 0; argv[argc] != NULL; ++argc)
467 /* http://graphics.stanford.edu/~seander/bithacks.html#DetermineIfPowerOf2 */
469 is_power_of_2 (unsigned long v)
471 return v && ((v & (v - 1)) == 0);
475 compare (const void *vp1, const void *vp2)
477 char * const *p1 = (char * const *) vp1;
478 char * const *p2 = (char * const *) vp2;
479 return strcmp (*p1, *p2);
483 sort_strings (char **argv, int len)
485 qsort (argv, len, sizeof (char *), compare);
489 free_strings (char **argv)
493 for (argc = 0; argv[argc] != NULL; ++argc)
499 free_stringslen (char **argv, int len)
503 for (i = 0; i < len; ++i)
508 /* Easy ways to run external commands. For full documentation, see
509 * 'commandrvf' below.
512 commandf (char **stdoutput, char **stderror, int flags, const char *name, ...)
519 /* Collect the command line arguments into an array. */
521 argv = malloc (sizeof (char *) * i);
526 argv[0] = (char *) name;
529 va_start (args, name);
531 while ((s = va_arg (args, char *)) != NULL) {
532 const char **p = realloc (argv, sizeof (char *) * (++i));
546 r = commandvf (stdoutput, stderror, flags, (const char * const*) argv);
548 /* NB: Mustn't free the strings which are on the stack. */
554 /* Same as 'command', but we allow the status code from the
555 * subcommand to be non-zero, and return that status code.
556 * We still return -1 if there was some other error.
559 commandrf (char **stdoutput, char **stderror, int flags, const char *name, ...)
566 /* Collect the command line arguments into an array. */
568 argv = malloc (sizeof (char *) * i);
573 argv[0] = (char *) name;
576 va_start (args, name);
578 while ((s = va_arg (args, char *)) != NULL) {
579 const char **p = realloc (argv, sizeof (char *) * (++i));
593 r = commandrvf (stdoutput, stderror, flags, argv);
595 /* NB: Mustn't free the strings which are on the stack. */
601 /* Same as 'command', but passing an argv. */
603 commandvf (char **stdoutput, char **stderror, int flags,
604 char const *const *argv)
608 r = commandrvf (stdoutput, stderror, flags, (void *) argv);
615 /* This is a more sane version of 'system(3)' for running external
616 * commands. It uses fork/execvp, so we don't need to worry about
617 * quoting of parameters, and it allows us to capture any error
618 * messages in a buffer.
620 * If stdoutput is not NULL, then *stdoutput will return the stdout
623 * If stderror is not NULL, then *stderror will return the stderr
624 * of the command. If there is a final \n character, it is removed
625 * so you can use the error string directly in a call to
630 * COMMAND_FLAG_FOLD_STDOUT_ON_STDERR: For broken external commands
631 * that send error messages to stdout (hello, parted) but that don't
632 * have any useful stdout information, use this flag to capture the
633 * error messages in the *stderror buffer. If using this flag,
634 * you should pass stdoutput as NULL because nothing could ever be
635 * captured in that buffer.
637 * COMMAND_FLAG_CHROOT_COPY_FILE_TO_STDIN: For running external
638 * commands on chrooted files correctly (see RHBZ#579608) specifying
639 * this flag causes another process to be forked which chroots into
640 * sysroot and just copies the input file to stdin of the specified
641 * command. The file descriptor is ORed with the flags, and that file
642 * descriptor is always closed by this function. See hexdump.c for an
646 commandrvf (char **stdoutput, char **stderror, int flags,
647 char const* const *argv)
649 int so_size = 0, se_size = 0;
650 int so_fd[2], se_fd[2];
651 int flag_copy_stdin = flags & COMMAND_FLAG_CHROOT_COPY_FILE_TO_STDIN;
652 int stdin_fd[2] = { -1, -1 };
653 pid_t pid, stdin_pid = -1;
659 if (stdoutput) *stdoutput = NULL;
660 if (stderror) *stderror = NULL;
663 printf ("%s", argv[0]);
664 for (i = 1; argv[i] != NULL; ++i)
665 printf (" %s", argv[i]);
669 /* Note: abort is used in a few places along the error paths early
670 * in this function. This is because (a) cleaning up correctly is
671 * very complex at these places and (b) abort is used when a
672 * resource problems is indicated which would be due to much more
673 * serious issues - eg. memory or file descriptor leaks. We
674 * wouldn't expect fork(2) or pipe(2) to fail in normal
678 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
679 error (0, errno, "pipe");
683 if (flag_copy_stdin) {
684 if (pipe (stdin_fd) == -1) {
685 error (0, errno, "pipe");
692 error (0, errno, "fork");
696 if (pid == 0) { /* Child process running the command. */
698 if (flag_copy_stdin) {
699 dup2 (stdin_fd[0], 0);
703 /* Set stdin to /dev/null (ignore failure) */
704 open ("/dev/null", O_RDONLY);
708 if (!(flags & COMMAND_FLAG_FOLD_STDOUT_ON_STDERR))
716 execvp (argv[0], (void *) argv);
718 _exit (EXIT_FAILURE);
721 if (flag_copy_stdin) {
722 int fd = flags & COMMAND_FLAG_FD_MASK;
725 if (stdin_pid == -1) {
726 error (0, errno, "fork");
730 if (stdin_pid == 0) { /* Child process copying stdin. */
737 dup2 (stdin_fd[1], 1);
741 if (chroot (sysroot) == -1) {
743 _exit (EXIT_FAILURE);
748 while ((n = read (fd, buffer, sizeof buffer)) > 0) {
749 if (xwrite (1, buffer, n) == -1)
750 /* EPIPE error indicates the command process has exited
751 * early. If the command process fails that will be caught
752 * by the daemon, and if not, then it's not an error.
754 _exit (errno == EPIPE ? EXIT_SUCCESS : EXIT_FAILURE);
759 _exit (EXIT_FAILURE);
762 if (close (fd) == -1) {
764 _exit (EXIT_FAILURE);
767 _exit (EXIT_SUCCESS);
775 /* Parent process. */
780 FD_SET (so_fd[0], &rset);
781 FD_SET (se_fd[0], &rset);
786 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
790 if (stdoutput) free (*stdoutput);
791 if (stderror) free (*stderror);
794 waitpid (pid, NULL, 0);
795 if (stdin_pid >= 0) waitpid (stdin_pid, NULL, 0);
799 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
800 r = read (so_fd[0], buf, sizeof buf);
805 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
807 if (r > 0 && stdoutput) {
809 p = realloc (*stdoutput, so_size);
815 memcpy (*stdoutput + so_size - r, buf, r);
819 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
820 r = read (se_fd[0], buf, sizeof buf);
825 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
829 ignore_value (write (2, buf, r));
833 p = realloc (*stderror, se_size);
839 memcpy (*stderror + se_size - r, buf, r);
848 /* Make sure the output buffers are \0-terminated. Also remove any
849 * trailing \n characters from the error buffer (not from stdout).
852 void *q = realloc (*stdoutput, so_size+1);
859 (*stdoutput)[so_size] = '\0';
862 void *q = realloc (*stderror, se_size+1);
869 (*stderror)[se_size] = '\0';
871 while (se_size >= 0 && (*stderror)[se_size] == '\n')
872 (*stderror)[se_size--] = '\0';
876 if (flag_copy_stdin) {
877 /* Check copy process didn't fail. */
878 if (waitpid (stdin_pid, &r, 0) != stdin_pid) {
881 waitpid (pid, NULL, 0);
885 if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) {
886 fprintf (stderr, "failed copying from input file, see earlier messages\n");
888 waitpid (pid, NULL, 0);
893 /* Get the exit status of the command. */
894 if (waitpid (pid, &r, 0) != pid) {
900 return WEXITSTATUS (r);
905 /* Split an output string into a NULL-terminated list of lines.
906 * Typically this is used where we have run an external command
907 * which has printed out a list of things, and we want to return
910 * The corner cases here are quite tricky. Note in particular:
914 * "a\nb" -> ["a"; "b"]
915 * "a\nb\n" -> ["a"; "b"]
916 * "a\nb\n\n" -> ["a"; "b"; ""]
918 * The original string is written over and destroyed by this
919 * function (which is usually OK because it's the 'out' string
920 * from command()). You can free the original string, because
921 * add_string() strdups the strings.
924 split_lines (char *str)
927 int size = 0, alloc = 0;
935 /* Empty last line? */
939 pend = strchr (p, '\n');
945 if (add_string (&lines, &size, &alloc, p) == -1) {
953 if (add_string (&lines, &size, &alloc, NULL) == -1)
959 /* Skip leading and trailing whitespace, updating the original string
965 size_t len = strlen (str);
967 while (len > 0 && c_isspace (str[len-1])) {
973 while (*p && c_isspace (*p)) {
978 memmove (str, p, len+1);
981 /* printf helper function so we can use %Q ("quoted") and %R to print
982 * shell-quoted strings. See guestfs(3)/EXTENDING LIBGUESTFS for more
986 print_shell_quote (FILE *stream,
987 const struct printf_info *info ATTRIBUTE_UNUSED,
988 const void *const *args)
990 #define SAFE(c) (c_isalnum((c)) || \
991 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
993 const char *str = *((const char **) (args[0]));
995 for (i = len = 0; str[i]; ++i) {
1000 putc (str[i], stream);
1008 print_sysroot_shell_quote (FILE *stream,
1009 const struct printf_info *info,
1010 const void *const *args)
1012 fputs (sysroot, stream);
1013 return sysroot_len + print_shell_quote (stream, info, args);
1016 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
1018 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
1019 size_t n, int *argtypes, int *size)
1022 argtypes[0] = PA_STRING;
1023 size[0] = sizeof (const char *);
1028 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
1030 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
1033 argtypes[0] = PA_STRING;
1037 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
1041 /* Perform device name translation. Don't call this directly -
1042 * use the RESOLVE_DEVICE macro.
1044 * See guestfs(3) for the algorithm.
1046 * We have to open the device and test for ENXIO, because
1047 * the device nodes themselves will exist in the appliance.
1050 device_name_translation (char *device)
1054 fd = open (device, O_RDONLY);
1061 if (errno != ENXIO && errno != ENOENT)
1064 /* If the name begins with "/dev/sd" then try the alternatives. */
1065 if (STRNEQLEN (device, "/dev/sd", 7))
1068 device[5] = 'h'; /* /dev/hd (old IDE driver) */
1069 fd = open (device, O_RDONLY);
1073 device[5] = 'v'; /* /dev/vd (for virtio devices) */
1074 fd = open (device, O_RDONLY);
1078 device[5] = 's'; /* Restore original device name. */
1082 /* Check program exists and is executable on $PATH. Actually, we
1083 * just assume PATH contains the default entries (see main() above).
1086 prog_exists (const char *prog)
1088 static const char * const dirs[] =
1089 { "/sbin", "/usr/sbin", "/bin", "/usr/bin" };
1093 for (i = 0; i < sizeof dirs / sizeof dirs[0]; ++i) {
1094 snprintf (buf, sizeof buf, "%s/%s", dirs[i], prog);
1095 if (access (buf, X_OK) == 0)
1101 /* LVM and other commands aren't synchronous, especially when udev is
1102 * involved. eg. You can create or remove some device, but the /dev
1103 * device node won't appear until some time later. This means that
1104 * you get an error if you run one command followed by another.
1106 * Use 'udevadm settle' after certain commands, but don't be too
1107 * fussed if it fails.
1109 * 'udevsettle' was the old name for this command (RHEL 5). This was
1110 * deprecated in favour of 'udevadm settle'. The old 'udevsettle'
1111 * command was left as a symlink. Then in Fedora 13 the old symlink
1112 * remained but it stopped working (RHBZ#548121), so we have to be
1113 * careful not to assume that we can use 'udevsettle' if it exists.
1118 (void) command (NULL, NULL, "udevadm", "settle", NULL);
1119 (void) command (NULL, NULL, "udevsettle", NULL);