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 /* Also in guestfs.c */
59 #define GUESTFWD_ADDR "10.0.2.4"
60 #define GUESTFWD_PORT "6666"
62 /* This is only a hint. If not defined, ignore it. */
64 # define AI_ADDRCONFIG 0
68 # define MAX(a,b) ((a)>(b)?(a):(b))
73 static int print_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
74 static int print_sysroot_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
75 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
76 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes, int *size);
78 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
79 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes);
81 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
87 daemon (int nochdir, int noclose)
90 "On Windows the daemon does not support forking into the "
91 "background.\nYou *must* run the daemon with the -f option.\n");
102 /* http://msdn2.microsoft.com/en-us/library/ms742213.aspx */
103 r = gl_sockets_startup (SOCKETS_2_2);
104 return r == 0 ? 0 : -1;
114 /* Location to mount root device. */
115 const char *sysroot = "/sysroot"; /* No trailing slash. */
118 /* Not used explicitly, but required by the gnulib 'error' module. */
119 const char *program_name = "guestfsd";
125 "guestfsd [-f|--foreground] [-c|--channel vmchannel] [-v|--verbose]\n");
129 main (int argc, char *argv[])
131 static const char *options = "fc:v?";
132 static const struct option long_options[] = {
133 { "channel", required_argument, 0, 'c' },
134 { "foreground", 0, 0, 'f' },
135 { "help", 0, 0, '?' },
136 { "verbose", 0, 0, 'v' },
142 char *vmchannel = NULL;
144 if (winsock_init () == -1)
145 error (EXIT_FAILURE, 0, "winsock initialization failed");
147 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
148 /* http://udrepper.livejournal.com/20948.html */
149 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
150 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
152 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
153 register_printf_function ('Q', print_shell_quote, print_arginfo);
154 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
156 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
161 c = getopt_long (argc, argv, options, long_options, NULL);
182 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
192 cmdline = read_cmdline ();
194 /* Set the verbose flag. */
196 (cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
198 printf ("verbose daemon enabled\n");
202 printf ("linux commmand line: %s\n", cmdline);
204 printf ("could not read linux command line\n");
208 /* Make sure SIGPIPE doesn't kill us. */
210 memset (&sa, 0, sizeof sa);
211 sa.sa_handler = SIG_IGN;
213 if (sigaction (SIGPIPE, &sa, NULL) == -1)
214 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
218 # define setenv(n,v,f) _putenv(n "=" v)
220 /* Set up a basic environment. After we are called by /init the
221 * environment is essentially empty.
222 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
224 * NOTE: if you change $PATH, you must also change 'prog_exists'
227 setenv ("PATH", "/sbin:/usr/sbin:/bin:/usr/bin", 1);
228 setenv ("SHELL", "/bin/sh", 1);
229 setenv ("LC_ALL", "C", 1);
232 /* We document that umask defaults to 022 (it should be this anyway). */
235 /* This is the default for Windows anyway. It's not even clear if
236 * Windows ever uses this -- the MSDN documentation for the function
237 * contains obvious errors.
242 /* Get the vmchannel string.
245 * --channel/-c option on the command line
246 * guestfs_vmchannel=... from the kernel command line
247 * guestfs=... from the kernel command line
250 * At the moment we expect this to contain "tcp:ip:port" but in
251 * future it might contain a device name, eg. "/dev/vcon4" for
252 * virtio-console vmchannel.
254 if (vmchannel == NULL && cmdline) {
258 p = strstr (cmdline, "guestfs_vmchannel=");
260 len = strcspn (p + 18, " \t\n");
261 vmchannel = strndup (p + 18, len);
268 /* Old libraries passed guestfs=host:port. Rewrite it as tcp:host:port. */
269 if (vmchannel == NULL) {
270 /* We will rewrite it part of the "guestfs=" string with
271 * "tcp:" hence p + 4 below. */
272 p = strstr (cmdline, "guestfs=");
274 len = strcspn (p + 4, " \t\n");
275 vmchannel = strndup (p + 4, len);
280 memcpy (vmchannel, "tcp:", 4);
285 /* Default vmchannel. */
286 if (vmchannel == NULL) {
287 vmchannel = strdup ("tcp:" GUESTFWD_ADDR ":" GUESTFWD_PORT);
295 printf ("vmchannel: %s\n", vmchannel);
297 /* Connect to vmchannel. */
300 if (STREQLEN (vmchannel, "tcp:", 4)) {
301 /* Resolve the hostname. */
302 struct addrinfo *res, *rr;
303 struct addrinfo hints;
308 port = strchr (host, ':');
313 fprintf (stderr, "vmchannel: expecting \"tcp:<ip>:<port>\": %s\n",
318 memset (&hints, 0, sizeof hints);
319 hints.ai_socktype = SOCK_STREAM;
320 hints.ai_flags = AI_ADDRCONFIG;
321 r = getaddrinfo (host, port, &hints, &res);
323 fprintf (stderr, "%s:%s: %s\n",
324 host, port, gai_strerror (r));
328 /* Connect to the given TCP socket. */
329 for (rr = res; rr != NULL; rr = rr->ai_next) {
330 sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
332 if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
343 "unknown vmchannel connection type: %s\n"
344 "expecting \"tcp:<ip>:<port>\"\n",
352 "Failed to connect to any vmchannel implementation.\n"
355 "This is a fatal error and the appliance will now exit.\n"
357 "Usually this error is caused by either QEMU or the appliance\n"
358 "kernel not supporting the vmchannel method that the\n"
359 "libguestfs library chose to use. Please run\n"
360 "'libguestfs-test-tool' and provide the complete, unedited\n"
361 "output to the libguestfs developers, either in a bug report\n"
362 "or on the libguestfs redhat com mailing list.\n"
368 /* Send the magic length message which indicates that
369 * userspace is up inside the guest.
373 uint32_t len = GUESTFS_LAUNCH_FLAG;
374 xdrmem_create (&xdr, lenbuf, sizeof lenbuf, XDR_ENCODE);
375 xdr_u_int (&xdr, &len);
377 if (xwrite (sock, lenbuf, sizeof lenbuf) == -1)
382 /* Fork into the background. */
384 if (daemon (0, 1) == -1) {
390 /* Enter the main loop, reading and performing actions. */
396 /* Read /proc/cmdline. */
400 int fd = open ("/proc/cmdline", O_RDONLY);
402 perror ("/proc/cmdline");
412 n = read (fd, buf, sizeof buf);
421 char *newr = realloc (r, len + n + 1); /* + 1 is for terminating NUL */
429 memcpy (&r[len], buf, n);
436 if (close (fd) == -1) {
445 /* Turn "/path" into "/sysroot/path".
447 * Caller must check for NULL and call reply_with_perror ("malloc")
448 * if it is. Caller must also free the string.
450 * See also the custom %R printf formatter which does shell quoting too.
453 sysroot_path (const char *path)
456 int len = strlen (path) + sysroot_len + 1;
462 snprintf (r, len, "%s%s", sysroot, path);
467 xwrite (int sock, const void *v_buf, size_t len)
470 const char *buf = v_buf;
473 r = write (sock, buf, len);
486 xread (int sock, void *v_buf, size_t len)
492 r = read (sock, buf, len);
498 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
509 add_string (char ***argv, int *size, int *alloc, const char *str)
514 if (*size >= *alloc) {
516 new_argv = realloc (*argv, *alloc * sizeof (char *));
517 if (new_argv == NULL) {
518 reply_with_perror ("realloc");
519 free_strings (*argv);
526 new_str = strdup (str);
527 if (new_str == NULL) {
528 reply_with_perror ("strdup");
529 free_strings (*argv);
534 (*argv)[*size] = new_str;
541 count_strings (char *const *argv)
545 for (argc = 0; argv[argc] != NULL; ++argc)
551 compare (const void *vp1, const void *vp2)
553 char * const *p1 = (char * const *) vp1;
554 char * const *p2 = (char * const *) vp2;
555 return strcmp (*p1, *p2);
559 sort_strings (char **argv, int len)
561 qsort (argv, len, sizeof (char *), compare);
565 free_strings (char **argv)
569 for (argc = 0; argv[argc] != NULL; ++argc)
575 free_stringslen (char **argv, int len)
579 for (i = 0; i < len; ++i)
584 /* Easy ways to run external commands. For full documentation, see
585 * 'commandrvf' below.
588 commandf (char **stdoutput, char **stderror, int flags, const char *name, ...)
595 /* Collect the command line arguments into an array. */
597 argv = malloc (sizeof (char *) * i);
602 argv[0] = (char *) name;
605 va_start (args, name);
607 while ((s = va_arg (args, char *)) != NULL) {
608 const char **p = realloc (argv, sizeof (char *) * (++i));
622 r = commandvf (stdoutput, stderror, flags, (const char * const*) argv);
624 /* NB: Mustn't free the strings which are on the stack. */
630 /* Same as 'command', but we allow the status code from the
631 * subcommand to be non-zero, and return that status code.
632 * We still return -1 if there was some other error.
635 commandrf (char **stdoutput, char **stderror, int flags, const char *name, ...)
642 /* Collect the command line arguments into an array. */
644 argv = malloc (sizeof (char *) * i);
649 argv[0] = (char *) name;
652 va_start (args, name);
654 while ((s = va_arg (args, char *)) != NULL) {
655 const char **p = realloc (argv, sizeof (char *) * (++i));
669 r = commandrvf (stdoutput, stderror, flags, argv);
671 /* NB: Mustn't free the strings which are on the stack. */
677 /* Same as 'command', but passing an argv. */
679 commandvf (char **stdoutput, char **stderror, int flags,
680 char const *const *argv)
684 r = commandrvf (stdoutput, stderror, flags, (void *) argv);
691 /* This is a more sane version of 'system(3)' for running external
692 * commands. It uses fork/execvp, so we don't need to worry about
693 * quoting of parameters, and it allows us to capture any error
694 * messages in a buffer.
696 * If stdoutput is not NULL, then *stdoutput will return the stdout
699 * If stderror is not NULL, then *stderror will return the stderr
700 * of the command. If there is a final \n character, it is removed
701 * so you can use the error string directly in a call to
706 * COMMAND_FLAG_FOLD_STDOUT_ON_STDERR: For broken external commands
707 * that send error messages to stdout (hello, parted) but that don't
708 * have any useful stdout information, use this flag to capture the
709 * error messages in the *stderror buffer. If using this flag,
710 * you should pass stdoutput as NULL because nothing could ever be
711 * captured in that buffer.
714 commandrvf (char **stdoutput, char **stderror, int flags,
715 char const* const *argv)
717 int so_size = 0, se_size = 0;
718 int so_fd[2], se_fd[2];
725 if (stdoutput) *stdoutput = NULL;
726 if (stderror) *stderror = NULL;
729 printf ("%s", argv[0]);
730 for (i = 1; argv[i] != NULL; ++i)
731 printf (" %s", argv[i]);
735 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
750 if (pid == 0) { /* Child process. */
752 open ("/dev/null", O_RDONLY); /* Set stdin to /dev/null (ignore failure) */
755 if (!(flags & COMMAND_FLAG_FOLD_STDOUT_ON_STDERR))
763 execvp (argv[0], (void *) argv);
768 /* Parent process. */
773 FD_SET (so_fd[0], &rset);
774 FD_SET (se_fd[0], &rset);
779 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
783 if (stdoutput) free (*stdoutput);
784 if (stderror) free (*stderror);
787 waitpid (pid, NULL, 0);
791 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
792 r = read (so_fd[0], buf, sizeof buf);
797 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
799 if (r > 0 && stdoutput) {
801 p = realloc (*stdoutput, so_size);
807 memcpy (*stdoutput + so_size - r, buf, r);
811 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
812 r = read (se_fd[0], buf, sizeof buf);
817 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
821 ignore_value (write (2, buf, r));
825 p = realloc (*stderror, se_size);
831 memcpy (*stderror + se_size - r, buf, r);
840 /* Make sure the output buffers are \0-terminated. Also remove any
841 * trailing \n characters from the error buffer (not from stdout).
844 void *q = realloc (*stdoutput, so_size+1);
851 (*stdoutput)[so_size] = '\0';
854 void *q = realloc (*stderror, se_size+1);
861 (*stderror)[se_size] = '\0';
863 while (se_size >= 0 && (*stderror)[se_size] == '\n')
864 (*stderror)[se_size--] = '\0';
868 /* Get the exit status of the command. */
869 if (waitpid (pid, &r, 0) != pid) {
875 return WEXITSTATUS (r);
880 /* Split an output string into a NULL-terminated list of lines.
881 * Typically this is used where we have run an external command
882 * which has printed out a list of things, and we want to return
885 * The corner cases here are quite tricky. Note in particular:
889 * "a\nb" -> ["a"; "b"]
890 * "a\nb\n" -> ["a"; "b"]
891 * "a\nb\n\n" -> ["a"; "b"; ""]
893 * The original string is written over and destroyed by this
894 * function (which is usually OK because it's the 'out' string
895 * from command()). You can free the original string, because
896 * add_string() strdups the strings.
899 split_lines (char *str)
902 int size = 0, alloc = 0;
910 /* Empty last line? */
914 pend = strchr (p, '\n');
920 if (add_string (&lines, &size, &alloc, p) == -1) {
928 if (add_string (&lines, &size, &alloc, NULL) == -1)
934 /* Skip leading and trailing whitespace, updating the original string
940 size_t len = strlen (str);
942 while (len > 0 && c_isspace (str[len-1])) {
948 while (*p && c_isspace (*p)) {
953 memmove (str, p, len+1);
956 /* printf helper function so we can use %Q ("quoted") and %R to print
957 * shell-quoted strings. See HACKING file for more details.
960 print_shell_quote (FILE *stream,
961 const struct printf_info *info ATTRIBUTE_UNUSED,
962 const void *const *args)
964 #define SAFE(c) (c_isalnum((c)) || \
965 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
967 const char *str = *((const char **) (args[0]));
969 for (i = len = 0; str[i]; ++i) {
974 putc (str[i], stream);
982 print_sysroot_shell_quote (FILE *stream,
983 const struct printf_info *info,
984 const void *const *args)
986 fputs (sysroot, stream);
987 return sysroot_len + print_shell_quote (stream, info, args);
990 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
992 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
993 size_t n, int *argtypes, int *size)
996 argtypes[0] = PA_STRING;
997 size[0] = sizeof (const char *);
1002 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
1004 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
1007 argtypes[0] = PA_STRING;
1011 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
1015 /* Perform device name translation. Don't call this directly -
1016 * use the RESOLVE_DEVICE macro.
1018 * See guestfs(3) for the algorithm.
1020 * We have to open the device and test for ENXIO, because
1021 * the device nodes themselves will exist in the appliance.
1024 device_name_translation (char *device, const char *func)
1028 fd = open (device, O_RDONLY);
1034 if (errno != ENXIO && errno != ENOENT) {
1036 reply_with_perror ("%s: %s", func, device);
1040 /* If the name begins with "/dev/sd" then try the alternatives. */
1041 if (STRNEQLEN (device, "/dev/sd", 7))
1044 device[5] = 'h'; /* /dev/hd (old IDE driver) */
1045 fd = open (device, O_RDONLY);
1051 device[5] = 'v'; /* /dev/vd (for virtio devices) */
1052 fd = open (device, O_RDONLY);
1058 device[5] = 's'; /* Restore original device name. */
1062 /* Check program exists and is executable on $PATH. Actually, we
1063 * just assume PATH contains the default entries (see main() above).
1066 prog_exists (const char *prog)
1068 static const char * const dirs[] =
1069 { "/sbin", "/usr/sbin", "/bin", "/usr/bin" };
1073 for (i = 0; i < sizeof dirs / sizeof dirs[0]; ++i) {
1074 snprintf (buf, sizeof buf, "%s/%s", dirs[i], prog);
1075 if (access (buf, X_OK) == 0)
1081 /* LVM and other commands aren't synchronous, especially when udev is
1082 * involved. eg. You can create or remove some device, but the /dev
1083 * device node won't appear until some time later. This means that
1084 * you get an error if you run one command followed by another.
1086 * Use 'udevadm settle' after certain commands, but don't be too
1087 * fussed if it fails.
1089 * 'udevsettle' was the old name for this command (RHEL 5). This was
1090 * deprecated in favour of 'udevadm settle'. The old 'udevsettle'
1091 * command was left as a symlink. Then in Fedora 13 the old symlink
1092 * remained but it stopped working (RHBZ#548121), so we have to be
1093 * careful not to assume that we can use 'udevsettle' if it exists.
1098 (void) command (NULL, NULL, "udevadm", "settle", NULL);
1099 (void) command (NULL, NULL, "udevsettle", NULL);