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) */
27 #include <rpc/types.h>
31 #include <sys/param.h>
32 #include <sys/select.h>
33 #include <sys/types.h>
43 static char *read_cmdline (void);
45 /* Also in guestfs.c */
46 #define GUESTFWD_ADDR "10.0.2.4"
47 #define GUESTFWD_PORT "6666"
51 static int print_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
52 static int print_sysroot_shell_quote (FILE *stream, const struct printf_info *info, const void *const *args);
53 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
54 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes, int *size);
56 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
57 static int print_arginfo (const struct printf_info *info, size_t n, int *argtypes);
59 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
63 /* Location to mount root device. */
64 const char *sysroot = "/sysroot"; /* No trailing slash. */
71 "guestfsd [-f|--foreground] [-c|--channel vmchannel] [-v|--verbose]\n");
75 main (int argc, char *argv[])
77 static const char *options = "fc:v?";
78 static const struct option long_options[] = {
79 { "channel", required_argument, 0, 'c' },
80 { "foreground", 0, 0, 'f' },
81 { "help", 0, 0, '?' },
82 { "verbose", 0, 0, 'v' },
88 char *vmchannel = NULL;
90 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
91 /* http://udrepper.livejournal.com/20948.html */
92 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
93 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
95 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
96 register_printf_function ('Q', print_shell_quote, print_arginfo);
97 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
99 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
104 c = getopt_long (argc, argv, options, long_options, NULL);
125 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
135 cmdline = read_cmdline ();
137 /* Set the verbose flag. */
139 (cmdline && strstr (cmdline, "guestfs_verbose=1") != NULL);
141 printf ("verbose daemon enabled\n");
145 printf ("linux commmand line: %s\n", cmdline);
147 printf ("could not read linux command line\n");
150 /* Make sure SIGPIPE doesn't kill us. */
152 memset (&sa, 0, sizeof sa);
153 sa.sa_handler = SIG_IGN;
155 if (sigaction (SIGPIPE, &sa, NULL) == -1)
156 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
158 /* Set up a basic environment. After we are called by /init the
159 * environment is essentially empty.
160 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
162 setenv ("PATH", "/usr/bin:/bin", 1);
163 setenv ("SHELL", "/bin/sh", 1);
164 setenv ("LC_ALL", "C", 1);
166 /* We document that umask defaults to 022 (it should be this anyway). */
169 /* Get the vmchannel string.
172 * --channel/-c option on the command line
173 * guestfs_vmchannel=... from the kernel command line
174 * guestfs=... from the kernel command line
177 * At the moment we expect this to contain "tcp:ip:port" but in
178 * future it might contain a device name, eg. "/dev/vcon4" for
179 * virtio-console vmchannel.
181 if (vmchannel == NULL && cmdline) {
185 p = strstr (cmdline, "guestfs_vmchannel=");
187 len = strcspn (p + 18, " \t\n");
188 vmchannel = strndup (p + 18, len);
195 /* Old libraries passed guestfs=host:port. Rewrite it as tcp:host:port. */
196 if (vmchannel == NULL) {
197 /* We will rewrite it part of the "guestfs=" string with
198 * "tcp:" hence p + 4 below. */
199 p = strstr (cmdline, "guestfs=");
201 len = strcspn (p + 4, " \t\n");
202 vmchannel = strndup (p + 4, len);
207 memcpy (vmchannel, "tcp:", 4);
212 /* Default vmchannel. */
213 if (vmchannel == NULL) {
214 vmchannel = strdup ("tcp:" GUESTFWD_ADDR ":" GUESTFWD_PORT);
222 printf ("vmchannel: %s\n", vmchannel);
224 /* Connect to vmchannel. */
227 if (strncmp (vmchannel, "tcp:", 4) == 0) {
228 /* Resolve the hostname. */
229 struct addrinfo *res, *rr;
230 struct addrinfo hints;
235 port = strchr (host, ':');
240 fprintf (stderr, "vmchannel: expecting \"tcp:<ip>:<port>\": %s\n",
245 memset (&hints, 0, sizeof hints);
246 hints.ai_socktype = SOCK_STREAM;
247 hints.ai_flags = AI_ADDRCONFIG;
248 r = getaddrinfo (host, port, &hints, &res);
250 fprintf (stderr, "%s:%s: %s\n",
251 host, port, gai_strerror (r));
255 /* Connect to the given TCP socket. */
256 for (rr = res; rr != NULL; rr = rr->ai_next) {
257 sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
259 if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
270 "unknown vmchannel connection type: %s\n"
271 "expecting \"tcp:<ip>:<port>\"\n",
279 "Failed to connect to any vmchannel implementation.\n"
282 "This is a fatal error and the appliance will now exit.\n"
284 "Usually this error is caused by either QEMU or the appliance\n"
285 "kernel not supporting the vmchannel method that the\n"
286 "libguestfs library chose to use. Please run\n"
287 "'libguestfs-test-tool' and provide the complete, unedited\n"
288 "output to the libguestfs developers, either in a bug report\n"
289 "or on the libguestfs redhat com mailing list.\n"
295 /* Send the magic length message which indicates that
296 * userspace is up inside the guest.
300 uint32_t len = GUESTFS_LAUNCH_FLAG;
301 xdrmem_create (&xdr, lenbuf, sizeof lenbuf, XDR_ENCODE);
302 xdr_uint32_t (&xdr, &len);
304 if (xwrite (sock, lenbuf, sizeof lenbuf) == -1)
309 /* Fork into the background. */
311 if (daemon (0, 1) == -1) {
317 /* Enter the main loop, reading and performing actions. */
323 /* Read /proc/cmdline. */
327 int fd = open ("/proc/cmdline", O_RDONLY);
329 perror ("/proc/cmdline");
339 n = read (fd, buf, sizeof buf);
348 char *newr = realloc (r, len + n + 1); /* + 1 is for terminating NUL */
356 memcpy (&r[len], buf, n);
363 if (close (fd) == -1) {
372 /* Turn "/path" into "/sysroot/path".
374 * Caller must check for NULL and call reply_with_perror ("malloc")
375 * if it is. Caller must also free the string.
377 * See also the custom %R printf formatter which does shell quoting too.
380 sysroot_path (const char *path)
383 int len = strlen (path) + sysroot_len + 1;
389 snprintf (r, len, "%s%s", sysroot, path);
394 xwrite (int sock, const void *v_buf, size_t len)
397 const char *buf = v_buf;
400 r = write (sock, buf, len);
413 xread (int sock, void *v_buf, size_t len)
419 r = read (sock, buf, len);
425 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
436 add_string (char ***argv, int *size, int *alloc, const char *str)
441 if (*size >= *alloc) {
443 new_argv = realloc (*argv, *alloc * sizeof (char *));
444 if (new_argv == NULL) {
445 reply_with_perror ("realloc");
446 free_strings (*argv);
453 new_str = strdup (str);
454 if (new_str == NULL) {
455 reply_with_perror ("strdup");
456 free_strings (*argv);
461 (*argv)[*size] = new_str;
468 count_strings (char *const *argv)
472 for (argc = 0; argv[argc] != NULL; ++argc)
478 compare (const void *vp1, const void *vp2)
480 char * const *p1 = (char * const *) vp1;
481 char * const *p2 = (char * const *) vp2;
482 return strcmp (*p1, *p2);
486 sort_strings (char **argv, int len)
488 qsort (argv, len, sizeof (char *), compare);
492 free_strings (char **argv)
496 for (argc = 0; argv[argc] != NULL; ++argc)
502 free_stringslen (char **argv, int len)
506 for (i = 0; i < len; ++i)
511 /* This is a more sane version of 'system(3)' for running external
512 * commands. It uses fork/execvp, so we don't need to worry about
513 * quoting of parameters, and it allows us to capture any error
514 * messages in a buffer.
517 command (char **stdoutput, char **stderror, const char *name, ...)
524 /* Collect the command line arguments into an array. */
526 argv = malloc (sizeof (char *) * i);
531 argv[0] = (char *) name;
534 va_start (args, name);
536 while ((s = va_arg (args, char *)) != NULL) {
537 const char **p = realloc (argv, sizeof (char *) * (++i));
551 r = commandv (stdoutput, stderror, (char **) argv);
553 /* NB: Mustn't free the strings which are on the stack. */
559 /* Same as 'command', but we allow the status code from the
560 * subcommand to be non-zero, and return that status code.
561 * We still return -1 if there was some other error.
564 commandr (char **stdoutput, char **stderror, const char *name, ...)
571 /* Collect the command line arguments into an array. */
573 argv = malloc (sizeof (char *) * i);
578 argv[0] = (char *) name;
581 va_start (args, name);
583 while ((s = va_arg (args, char *)) != NULL) {
584 const char **p = realloc (argv, sizeof (char *) * (++i));
598 r = commandrv (stdoutput, stderror, argv);
600 /* NB: Mustn't free the strings which are on the stack. */
606 /* Same as 'command', but passing an argv. */
608 commandv (char **stdoutput, char **stderror, char *const *argv)
612 r = commandrv (stdoutput, stderror, (void *) argv);
620 commandrv (char **stdoutput, char **stderror, char const* const *argv)
622 int so_size = 0, se_size = 0;
623 int so_fd[2], se_fd[2];
630 if (stdoutput) *stdoutput = NULL;
631 if (stderror) *stderror = NULL;
634 printf ("%s", argv[0]);
635 for (i = 1; argv[i] != NULL; ++i)
636 printf (" %s", argv[i]);
640 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
655 if (pid == 0) { /* Child process. */
657 open ("/dev/null", O_RDONLY); /* Set stdin to /dev/null (ignore failure) */
665 execvp (argv[0], (void *) argv);
670 /* Parent process. */
675 FD_SET (so_fd[0], &rset);
676 FD_SET (se_fd[0], &rset);
681 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
685 if (stdoutput) free (*stdoutput);
686 if (stderror) free (*stderror);
689 waitpid (pid, NULL, 0);
693 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
694 r = read (so_fd[0], buf, sizeof buf);
699 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
701 if (r > 0 && stdoutput) {
703 p = realloc (*stdoutput, so_size);
709 memcpy (*stdoutput + so_size - r, buf, r);
713 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
714 r = read (se_fd[0], buf, sizeof buf);
719 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
721 if (r > 0 && stderror) {
723 p = realloc (*stderror, se_size);
729 memcpy (*stderror + se_size - r, buf, r);
737 /* Make sure the output buffers are \0-terminated. Also remove any
738 * trailing \n characters from the error buffer (not from stdout).
741 void *q = realloc (*stdoutput, so_size+1);
748 (*stdoutput)[so_size] = '\0';
751 void *q = realloc (*stderror, se_size+1);
758 (*stderror)[se_size] = '\0';
760 while (se_size >= 0 && (*stderror)[se_size] == '\n')
761 (*stderror)[se_size--] = '\0';
765 /* Get the exit status of the command. */
766 if (waitpid (pid, &r, 0) != pid) {
772 return WEXITSTATUS (r);
777 /* Split an output string into a NULL-terminated list of lines.
778 * Typically this is used where we have run an external command
779 * which has printed out a list of things, and we want to return
782 * The corner cases here are quite tricky. Note in particular:
786 * "a\nb" -> ["a"; "b"]
787 * "a\nb\n" -> ["a"; "b"]
788 * "a\nb\n\n" -> ["a"; "b"; ""]
790 * The original string is written over and destroyed by this
791 * function (which is usually OK because it's the 'out' string
792 * from command()). You can free the original string, because
793 * add_string() strdups the strings.
796 split_lines (char *str)
799 int size = 0, alloc = 0;
802 if (strcmp (str, "") == 0)
807 /* Empty last line? */
811 pend = strchr (p, '\n');
817 if (add_string (&lines, &size, &alloc, p) == -1) {
825 if (add_string (&lines, &size, &alloc, NULL) == -1)
831 /* printf helper function so we can use %Q ("quoted") and %R to print
832 * shell-quoted strings. See HACKING file for more details.
835 print_shell_quote (FILE *stream,
836 const struct printf_info *info ATTRIBUTE_UNUSED,
837 const void *const *args)
839 #define SAFE(c) (c_isalnum((c)) || \
840 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
842 const char *str = *((const char **) (args[0]));
844 for (i = len = 0; str[i]; ++i) {
849 putc (str[i], stream);
857 print_sysroot_shell_quote (FILE *stream,
858 const struct printf_info *info,
859 const void *const *args)
861 fputs (sysroot, stream);
862 return sysroot_len + print_shell_quote (stream, info, args);
865 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
867 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
868 size_t n, int *argtypes, int *size)
871 argtypes[0] = PA_STRING;
872 size[0] = sizeof (const char *);
877 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
879 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
882 argtypes[0] = PA_STRING;
886 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
890 /* Perform device name translation. Don't call this directly -
891 * use the RESOLVE_DEVICE macro.
893 * See guestfs(3) for the algorithm.
895 * We have to open the device and test for ENXIO, because
896 * the device nodes themselves will exist in the appliance.
899 device_name_translation (char *device, const char *func)
903 fd = open (device, O_RDONLY);
909 if (errno != ENXIO && errno != ENOENT) {
911 reply_with_perror ("%s: %s", func, device);
915 /* If the name begins with "/dev/sd" then try the alternatives. */
916 if (strncmp (device, "/dev/sd", 7) != 0)
919 device[5] = 'h'; /* /dev/hd (old IDE driver) */
920 fd = open (device, O_RDONLY);
926 device[5] = 'v'; /* /dev/vd (for virtio devices) */
927 fd = open (device, O_RDONLY);
933 device[5] = 's'; /* Restore original device name. */
937 /* LVM and other commands aren't synchronous, especially when udev is
938 * involved. eg. You can create or remove some device, but the /dev
939 * device node won't appear until some time later. This means that
940 * you get an error if you run one command followed by another.
941 * Use 'udevadm settle' after certain commands, but don't be too
942 * fussed if it fails.
947 command (NULL, NULL, "/sbin/udevadm", "settle", NULL);