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 void usage (void);
45 /* Also in guestfs.c */
46 #define GUESTFWD_PORT "6666"
47 #define GUESTFWD_ADDR "10.0.2.4"
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. */
68 main (int argc, char *argv[])
70 static const char *options = "f?";
71 static const struct option long_options[] = {
72 { "foreground", 0, 0, 'f' },
73 { "help", 0, 0, '?' },
82 struct addrinfo *res, *rr;
83 struct addrinfo hints;
88 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
89 /* http://udrepper.livejournal.com/20948.html */
90 register_printf_specifier ('Q', print_shell_quote, print_arginfo);
91 register_printf_specifier ('R', print_sysroot_shell_quote, print_arginfo);
93 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
94 register_printf_function ('Q', print_shell_quote, print_arginfo);
95 register_printf_function ('R', print_sysroot_shell_quote, print_arginfo);
97 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
102 c = getopt_long (argc, argv, options, long_options, NULL);
115 fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c);
125 /* Set the verbose flag. */
126 fp = fopen ("/proc/cmdline", "r");
128 perror ("/proc/cmdline");
131 n = fread (buf, 1, sizeof buf - 1, fp);
135 verbose = strstr (buf, "guestfs_verbose=1") != NULL;
137 printf ("verbose daemon enabled\n");
140 /* Make sure SIGPIPE doesn't kill us. */
141 memset (&sa, 0, sizeof sa);
142 sa.sa_handler = SIG_IGN;
144 if (sigaction (SIGPIPE, &sa, NULL) == -1)
145 perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */
147 /* Set up a basic environment. After we are called by /init the
148 * environment is essentially empty.
149 * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5
151 setenv ("PATH", "/usr/bin:/bin", 1);
152 setenv ("SHELL", "/bin/sh", 1);
153 setenv ("LC_ALL", "C", 1);
155 /* We document that umask defaults to 022 (it should be this anyway). */
158 /* Resolve the hostname. */
159 memset (&hints, 0, sizeof hints);
160 hints.ai_socktype = SOCK_STREAM;
161 hints.ai_flags = AI_ADDRCONFIG;
162 r = getaddrinfo (GUESTFWD_ADDR, GUESTFWD_PORT, &hints, &res);
164 fprintf (stderr, "%s:%s: %s\n",
165 GUESTFWD_ADDR, GUESTFWD_PORT, gai_strerror (r));
169 /* Connect to the given TCP socket. */
171 for (rr = res; rr != NULL; rr = rr->ai_next) {
172 sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol);
174 if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0)
185 fprintf (stderr, "connection to %s:%s failed\n",
186 GUESTFWD_ADDR, GUESTFWD_PORT);
190 /* Send the magic length message which indicates that
191 * userspace is up inside the guest.
193 len = GUESTFS_LAUNCH_FLAG;
194 xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE);
195 if (!xdr_uint32_t (&xdr, &len)) {
196 fprintf (stderr, "xdr_uint32_t failed\n");
200 if (xwrite (sock, buf, xdr_getpos (&xdr)) == -1)
205 /* Fork into the background. */
207 if (daemon (0, 1) == -1) {
213 /* Enter the main loop, reading and performing actions. */
219 /* Turn "/path" into "/sysroot/path".
221 * Caller must check for NULL and call reply_with_perror ("malloc")
222 * if it is. Caller must also free the string.
224 * See also the custom %R printf formatter which does shell quoting too.
227 sysroot_path (const char *path)
230 int len = strlen (path) + sysroot_len + 1;
236 snprintf (r, len, "%s%s", sysroot, path);
241 xwrite (int sock, const void *v_buf, size_t len)
244 const char *buf = v_buf;
247 r = write (sock, buf, len);
260 xread (int sock, void *v_buf, size_t len)
266 r = read (sock, buf, len);
272 fprintf (stderr, "read: unexpected end of file on fd %d\n", sock);
285 fprintf (stderr, "guestfsd [-f]\n");
289 add_string (char ***argv, int *size, int *alloc, const char *str)
294 if (*size >= *alloc) {
296 new_argv = realloc (*argv, *alloc * sizeof (char *));
297 if (new_argv == NULL) {
298 reply_with_perror ("realloc");
299 free_strings (*argv);
306 new_str = strdup (str);
307 if (new_str == NULL) {
308 reply_with_perror ("strdup");
309 free_strings (*argv);
314 (*argv)[*size] = new_str;
321 count_strings (char *const *argv)
325 for (argc = 0; argv[argc] != NULL; ++argc)
331 compare (const void *vp1, const void *vp2)
333 char * const *p1 = (char * const *) vp1;
334 char * const *p2 = (char * const *) vp2;
335 return strcmp (*p1, *p2);
339 sort_strings (char **argv, int len)
341 qsort (argv, len, sizeof (char *), compare);
345 free_strings (char **argv)
349 for (argc = 0; argv[argc] != NULL; ++argc)
355 free_stringslen (char **argv, int len)
359 for (i = 0; i < len; ++i)
364 /* This is a more sane version of 'system(3)' for running external
365 * commands. It uses fork/execvp, so we don't need to worry about
366 * quoting of parameters, and it allows us to capture any error
367 * messages in a buffer.
370 command (char **stdoutput, char **stderror, const char *name, ...)
377 /* Collect the command line arguments into an array. */
379 argv = malloc (sizeof (char *) * i);
384 argv[0] = (char *) name;
387 va_start (args, name);
389 while ((s = va_arg (args, char *)) != NULL) {
390 const char **p = realloc (argv, sizeof (char *) * (++i));
404 r = commandv (stdoutput, stderror, (char **) argv);
406 /* NB: Mustn't free the strings which are on the stack. */
412 /* Same as 'command', but we allow the status code from the
413 * subcommand to be non-zero, and return that status code.
414 * We still return -1 if there was some other error.
417 commandr (char **stdoutput, char **stderror, const char *name, ...)
424 /* Collect the command line arguments into an array. */
426 argv = malloc (sizeof (char *) * i);
431 argv[0] = (char *) name;
434 va_start (args, name);
436 while ((s = va_arg (args, char *)) != NULL) {
437 const char **p = realloc (argv, sizeof (char *) * (++i));
451 r = commandrv (stdoutput, stderror, argv);
453 /* NB: Mustn't free the strings which are on the stack. */
459 /* Same as 'command', but passing an argv. */
461 commandv (char **stdoutput, char **stderror, char *const *argv)
465 r = commandrv (stdoutput, stderror, (void *) argv);
473 commandrv (char **stdoutput, char **stderror, char const* const *argv)
475 int so_size = 0, se_size = 0;
476 int so_fd[2], se_fd[2];
483 if (stdoutput) *stdoutput = NULL;
484 if (stderror) *stderror = NULL;
487 printf ("%s", argv[0]);
488 for (i = 1; argv[i] != NULL; ++i)
489 printf (" %s", argv[i]);
493 if (pipe (so_fd) == -1 || pipe (se_fd) == -1) {
508 if (pid == 0) { /* Child process. */
517 execvp (argv[0], (void *) argv);
522 /* Parent process. */
527 FD_SET (so_fd[0], &rset);
528 FD_SET (se_fd[0], &rset);
533 r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL);
537 if (stdoutput) free (*stdoutput);
538 if (stderror) free (*stderror);
541 waitpid (pid, NULL, 0);
545 if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */
546 r = read (so_fd[0], buf, sizeof buf);
551 if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; }
553 if (r > 0 && stdoutput) {
555 p = realloc (*stdoutput, so_size);
561 memcpy (*stdoutput + so_size - r, buf, r);
565 if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */
566 r = read (se_fd[0], buf, sizeof buf);
571 if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; }
573 if (r > 0 && stderror) {
575 p = realloc (*stderror, se_size);
581 memcpy (*stderror + se_size - r, buf, r);
589 /* Make sure the output buffers are \0-terminated. Also remove any
590 * trailing \n characters from the error buffer (not from stdout).
593 void *q = realloc (*stdoutput, so_size+1);
600 (*stdoutput)[so_size] = '\0';
603 void *q = realloc (*stderror, se_size+1);
610 (*stderror)[se_size] = '\0';
612 while (se_size >= 0 && (*stderror)[se_size] == '\n')
613 (*stderror)[se_size--] = '\0';
617 /* Get the exit status of the command. */
618 if (waitpid (pid, &r, 0) != pid) {
624 return WEXITSTATUS (r);
629 /* Split an output string into a NULL-terminated list of lines.
630 * Typically this is used where we have run an external command
631 * which has printed out a list of things, and we want to return
634 * The corner cases here are quite tricky. Note in particular:
638 * "a\nb" -> ["a"; "b"]
639 * "a\nb\n" -> ["a"; "b"]
640 * "a\nb\n\n" -> ["a"; "b"; ""]
642 * The original string is written over and destroyed by this
643 * function (which is usually OK because it's the 'out' string
644 * from command()). You can free the original string, because
645 * add_string() strdups the strings.
648 split_lines (char *str)
651 int size = 0, alloc = 0;
654 if (strcmp (str, "") == 0)
659 /* Empty last line? */
663 pend = strchr (p, '\n');
669 if (add_string (&lines, &size, &alloc, p) == -1) {
677 if (add_string (&lines, &size, &alloc, NULL) == -1)
683 /* printf helper function so we can use %Q ("quoted") and %R to print
684 * shell-quoted strings. See HACKING file for more details.
687 print_shell_quote (FILE *stream,
688 const struct printf_info *info ATTRIBUTE_UNUSED,
689 const void *const *args)
691 #define SAFE(c) (isalnum((c)) || \
692 (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.')
694 const char *str = *((const char **) (args[0]));
696 for (i = len = 0; str[i]; ++i) {
701 putc (str[i], stream);
709 print_sysroot_shell_quote (FILE *stream,
710 const struct printf_info *info,
711 const void *const *args)
713 fputs (sysroot, stream);
714 return sysroot_len + print_shell_quote (stream, info, args);
717 #ifdef HAVE_REGISTER_PRINTF_SPECIFIER
719 print_arginfo (const struct printf_info *info ATTRIBUTE_UNUSED,
720 size_t n, int *argtypes, int *size)
723 argtypes[0] = PA_STRING;
724 size[0] = sizeof (const char *);
729 #ifdef HAVE_REGISTER_PRINTF_FUNCTION
731 print_arginfo (const struct printf_info *info, size_t n, int *argtypes)
734 argtypes[0] = PA_STRING;
738 #error "HAVE_REGISTER_PRINTF_{SPECIFIER|FUNCTION} not defined"
742 /* Perform device name translation. Don't call this directly -
743 * use the RESOLVE_DEVICE macro.
745 * See guestfs(3) for the algorithm.
747 * We have to open the device and test for ENXIO, because
748 * the device nodes themselves will exist in the appliance.
751 device_name_translation (char *device, const char *func)
755 fd = open (device, O_RDONLY);
761 if (errno != ENXIO && errno != ENOENT) {
763 reply_with_perror ("%s: %s", func, device);
767 /* If the name begins with "/dev/sd" then try the alternatives. */
768 if (strncmp (device, "/dev/sd", 7) != 0)
771 device[5] = 'h'; /* /dev/hd (old IDE driver) */
772 fd = open (device, O_RDONLY);
778 device[5] = 'v'; /* /dev/vd (for virtio devices) */
779 fd = open (device, O_RDONLY);
785 device[5] = 's'; /* Restore original device name. */
789 /* LVM and other commands aren't synchronous, especially when udev is
790 * involved. eg. You can create or remove some device, but the /dev
791 * device node won't appear until some time later. This means that
792 * you get an error if you run one command followed by another.
793 * Use 'udevadm settle' after certain commands, but don't be too
794 * fussed if it fails.
799 command (NULL, NULL, "/sbin/udevadm", "settle", NULL);