/* libguestfs - the guestfsd daemon * Copyright (C) 2009 Red Hat Inc. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #define _BSD_SOURCE /* for daemon(3) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "daemon.h" static void usage (void); /* Also in guestfs.c */ #define VMCHANNEL_PORT "6666" #define VMCHANNEL_ADDR "10.0.2.4" int verbose = 0; int main (int argc, char *argv[]) { static const char *options = "fh:p:?"; static struct option long_options[] = { { "foreground", 0, 0, 'f' }, { "help", 0, 0, '?' }, { "host", 1, 0, 'h' }, { "port", 1, 0, 'p' }, { 0, 0, 0, 0 } }; int c, n, r; int dont_fork = 0; const char *host = NULL; const char *port = NULL; FILE *fp; char buf[4096]; char *p, *p2; int sock; struct addrinfo *res, *rr; struct addrinfo hints; XDR xdr; uint32_t len; struct sigaction sa; for (;;) { c = getopt_long (argc, argv, options, long_options, NULL); if (c == -1) break; switch (c) { case 'f': dont_fork = 1; break; case 'h': host = optarg; break; case 'p': port = optarg; break; case '?': usage (); exit (0); default: fprintf (stderr, "guestfsd: unexpected command line option 0x%x\n", c); exit (1); } } if (optind < argc) { usage (); exit (1); } /* If host and port aren't set yet, try /proc/cmdline. */ if (!host || !port) { fp = fopen ("/proc/cmdline", "r"); if (fp == NULL) { perror ("/proc/cmdline"); goto next; } n = fread (buf, 1, sizeof buf - 1, fp); fclose (fp); buf[n] = '\0'; /* Set the verbose flag. Not quite right because this will only * set the flag if host and port aren't set on the command line. * Don't worry about this for now. (XXX) */ verbose = strstr (buf, "guestfs_verbose=1") != NULL; if (verbose) printf ("verbose daemon enabled\n"); p = strstr (buf, "guestfs="); if (p) { p += 8; p2 = strchr (p, ':'); if (p2) { *p2++ = '\0'; host = p; r = strcspn (p2, " \n"); p2[r] = '\0'; port = p2; } } } next: /* Can't parse /proc/cmdline, so use built-in defaults. */ if (!host || !port) { host = VMCHANNEL_ADDR; port = VMCHANNEL_PORT; } /* Make sure SIGPIPE doesn't kill us. */ memset (&sa, 0, sizeof sa); sa.sa_handler = SIG_IGN; sa.sa_flags = 0; if (sigaction (SIGPIPE, &sa, NULL) == -1) perror ("sigaction SIGPIPE"); /* but try to continue anyway ... */ /* Set up a basic environment. After we are called by /init the * environment is essentially empty. * https://bugzilla.redhat.com/show_bug.cgi?id=502074#c5 */ setenv ("PATH", "/usr/bin:/bin", 1); setenv ("SHELL", "/bin/sh", 1); setenv ("LANG", "C", 1); /* We document that umask defaults to 022 (it should be this anyway). */ umask (022); /* Resolve the hostname. */ memset (&hints, 0, sizeof hints); hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_ADDRCONFIG; r = getaddrinfo (host, port, &hints, &res); if (r != 0) { fprintf (stderr, "%s:%s: %s\n", host, port, gai_strerror (r)); exit (1); } /* Connect to the given TCP socket. */ sock = -1; for (rr = res; rr != NULL; rr = rr->ai_next) { sock = socket (rr->ai_family, rr->ai_socktype, rr->ai_protocol); if (sock != -1) { if (connect (sock, rr->ai_addr, rr->ai_addrlen) == 0) break; perror ("connect"); close (sock); sock = -1; } } freeaddrinfo (res); if (sock == -1) { fprintf (stderr, "connection to %s:%s failed\n", host, port); exit (1); } /* Send the magic length message which indicates that * userspace is up inside the guest. */ len = GUESTFS_LAUNCH_FLAG; xdrmem_create (&xdr, buf, sizeof buf, XDR_ENCODE); if (!xdr_uint32_t (&xdr, &len)) { fprintf (stderr, "xdr_uint32_t failed\n"); exit (1); } (void) xwrite (sock, buf, xdr_getpos (&xdr)); xdr_destroy (&xdr); /* Fork into the background. */ if (!dont_fork) { if (daemon (0, 1) == -1) { perror ("daemon"); exit (1); } } /* Enter the main loop, reading and performing actions. */ main_loop (sock); exit (0); } int xwrite (int sock, const void *buf, size_t len) { int r; while (len > 0) { r = write (sock, buf, len); if (r == -1) { perror ("write"); return -1; } buf += r; len -= r; } return 0; } int xread (int sock, void *buf, size_t len) { int r; while (len > 0) { r = read (sock, buf, len); if (r == -1) { perror ("read"); return -1; } if (r == 0) { fprintf (stderr, "read: unexpected end of file on fd %d\n", sock); return -1; } buf += r; len -= r; } return 0; } static void usage (void) { fprintf (stderr, "guestfsd [-f] [-h host -p port]\n"); } int add_string (char ***argv, int *size, int *alloc, const char *str) { char **new_argv; char *new_str; if (*size >= *alloc) { *alloc += 64; new_argv = realloc (*argv, *alloc * sizeof (char *)); if (new_argv == NULL) { reply_with_perror ("realloc"); free_strings (*argv); return -1; } *argv = new_argv; } if (str) { new_str = strdup (str); if (new_str == NULL) { reply_with_perror ("strdup"); free_strings (*argv); } } else new_str = NULL; (*argv)[*size] = new_str; (*size)++; return 0; } int count_strings (char * const* const argv) { int argc; for (argc = 0; argv[argc] != NULL; ++argc) ; return argc; } static int compare (const void *vp1, const void *vp2) { char * const *p1 = (char * const *) vp1; char * const *p2 = (char * const *) vp2; return strcmp (*p1, *p2); } void sort_strings (char **argv, int len) { qsort (argv, len, sizeof (char *), compare); } void free_strings (char **argv) { int argc; for (argc = 0; argv[argc] != NULL; ++argc) free (argv[argc]); free (argv); } void free_stringslen (char **argv, int len) { int i; for (i = 0; i < len; ++i) free (argv[i]); free (argv); } /* This is a more sane version of 'system(3)' for running external * commands. It uses fork/execvp, so we don't need to worry about * quoting of parameters, and it allows us to capture any error * messages in a buffer. */ int command (char **stdoutput, char **stderror, const char *name, ...) { va_list args; char **argv, **p; char *s; int i, r; /* Collect the command line arguments into an array. */ i = 2; argv = malloc (sizeof (char *) * i); if (argv == NULL) { perror ("malloc"); return -1; } argv[0] = (char *) name; argv[1] = NULL; va_start (args, name); while ((s = va_arg (args, char *)) != NULL) { p = realloc (argv, sizeof (char *) * (++i)); if (p == NULL) { perror ("realloc"); free (argv); va_end (args); return -1; } argv = p; argv[i-2] = s; argv[i-1] = NULL; } va_end (args); r = commandv (stdoutput, stderror, argv); /* NB: Mustn't free the strings which are on the stack. */ free (argv); return r; } /* Same as 'command', but we allow the status code from the * subcommand to be non-zero, and return that status code. * We still return -1 if there was some other error. */ int commandr (char **stdoutput, char **stderror, const char *name, ...) { va_list args; char **argv, **p; char *s; int i, r; /* Collect the command line arguments into an array. */ i = 2; argv = malloc (sizeof (char *) * i); if (argv == NULL) { perror ("malloc"); return -1; } argv[0] = (char *) name; argv[1] = NULL; va_start (args, name); while ((s = va_arg (args, char *)) != NULL) { p = realloc (argv, sizeof (char *) * (++i)); if (p == NULL) { perror ("realloc"); free (argv); va_end (args); return -1; } argv = p; argv[i-2] = s; argv[i-1] = NULL; } va_end (args); r = commandrv (stdoutput, stderror, argv); /* NB: Mustn't free the strings which are on the stack. */ free (argv); return r; } /* Same as 'command', but passing an argv. */ int commandv (char **stdoutput, char **stderror, char * const* const argv) { int r; r = commandrv (stdoutput, stderror, argv); if (r == 0) return 0; else return -1; } int commandrv (char **stdoutput, char **stderror, char * const* const argv) { int so_size = 0, se_size = 0; int so_fd[2], se_fd[2]; pid_t pid; int r, quit, i; fd_set rset, rset2; char buf[256]; char *p; if (stdoutput) *stdoutput = NULL; if (stderror) *stderror = NULL; if (verbose) { printf ("%s", argv[0]); for (i = 1; argv[i] != NULL; ++i) printf (" %s", argv[i]); printf ("\n"); } if (pipe (so_fd) == -1 || pipe (se_fd) == -1) { perror ("pipe"); return -1; } pid = fork (); if (pid == -1) { perror ("fork"); close (so_fd[0]); close (so_fd[1]); close (se_fd[0]); close (se_fd[1]); return -1; } if (pid == 0) { /* Child process. */ close (0); close (so_fd[0]); close (se_fd[0]); dup2 (so_fd[1], 1); dup2 (se_fd[1], 2); close (so_fd[1]); close (se_fd[1]); execvp (argv[0], argv); perror (argv[0]); _exit (1); } /* Parent process. */ close (so_fd[1]); close (se_fd[1]); FD_ZERO (&rset); FD_SET (so_fd[0], &rset); FD_SET (se_fd[0], &rset); quit = 0; while (quit < 2) { rset2 = rset; r = select (MAX (so_fd[0], se_fd[0]) + 1, &rset2, NULL, NULL, NULL); if (r == -1) { perror ("select"); quit: if (stdoutput) free (*stdoutput); if (stderror) free (*stderror); close (so_fd[0]); close (se_fd[0]); waitpid (pid, NULL, 0); return -1; } if (FD_ISSET (so_fd[0], &rset2)) { /* something on stdout */ r = read (so_fd[0], buf, sizeof buf); if (r == -1) { perror ("read"); goto quit; } if (r == 0) { FD_CLR (so_fd[0], &rset); quit++; } if (r > 0 && stdoutput) { so_size += r; p = realloc (*stdoutput, so_size); if (p == NULL) { perror ("realloc"); goto quit; } *stdoutput = p; memcpy (*stdoutput + so_size - r, buf, r); } } if (FD_ISSET (se_fd[0], &rset2)) { /* something on stderr */ r = read (se_fd[0], buf, sizeof buf); if (r == -1) { perror ("read"); goto quit; } if (r == 0) { FD_CLR (se_fd[0], &rset); quit++; } if (r > 0 && stderror) { se_size += r; p = realloc (*stderror, se_size); if (p == NULL) { perror ("realloc"); goto quit; } *stderror = p; memcpy (*stderror + se_size - r, buf, r); } } } close (so_fd[0]); close (se_fd[0]); /* Make sure the output buffers are \0-terminated. Also remove any * trailing \n characters from the error buffer (not from stdout). */ if (stdoutput) { *stdoutput = realloc (*stdoutput, so_size+1); if (*stdoutput == NULL) { perror ("realloc"); *stdoutput = NULL; } else (*stdoutput)[so_size] = '\0'; } if (stderror) { *stderror = realloc (*stderror, se_size+1); if (*stderror == NULL) { perror ("realloc"); *stderror = NULL; } else { (*stderror)[se_size] = '\0'; se_size--; while (se_size >= 0 && (*stderror)[se_size] == '\n') (*stderror)[se_size--] = '\0'; } } /* Get the exit status of the command. */ if (waitpid (pid, &r, 0) != pid) { perror ("waitpid"); return -1; } if (WIFEXITED (r)) { return WEXITSTATUS (r); } else return -1; } /* Split an output string into a NULL-terminated list of lines. * Typically this is used where we have run an external command * which has printed out a list of things, and we want to return * an actual list. * * The corner cases here are quite tricky. Note in particular: * * "" -> [] * "\n" -> [""] * "a\nb" -> ["a"; "b"] * "a\nb\n" -> ["a"; "b"] * "a\nb\n\n" -> ["a"; "b"; ""] * * The original string is written over and destroyed by this * function (which is usually OK because it's the 'out' string * from command()). You can free the original string, because * add_string() strdups the strings. */ char ** split_lines (char *str) { char **lines = NULL; int size = 0, alloc = 0; char *p, *pend; if (strcmp (str, "") == 0) goto empty_list; p = str; while (p) { /* Empty last line? */ if (p[0] == '\0') break; pend = strchr (p, '\n'); if (pend) { *pend = '\0'; pend++; } if (add_string (&lines, &size, &alloc, p) == -1) { return NULL; } p = pend; } empty_list: if (add_string (&lines, &size, &alloc, NULL) == -1) return NULL; return lines; } /* Quote 'in' for the shell, and write max len-1 bytes to out. The * result will be NUL-terminated, even if it is truncated. * * Returns number of bytes needed, so if result >= len then the buffer * should have been longer. * * XXX This doesn't quote \n correctly (but is still safe). */ int shell_quote (char *out, int len, const char *in) { #define SAFE(c) (isalnum((c)) || \ (c) == '/' || (c) == '-' || (c) == '_' || (c) == '.') int i, j; int outlen = strlen (in); /* Calculate how much output space this really needs. */ for (i = 0; in[i]; ++i) if (!SAFE (in[i])) outlen++; /* Now copy the string, but only up to len-1 bytes. */ for (i = 0, j = 0; in[i]; ++i) { int is_safe = SAFE (in[i]); /* Enough space left to write this character? */ if (j >= len-1 || (!is_safe && j >= len-2)) break; if (!is_safe) out[j++] = '\\'; out[j++] = in[i]; } out[j] = '\0'; return outlen; } /* Perform device name translation. Don't call this directly - * use the IS_DEVICE macro. * * See guestfs(3) for the algorithm. * * We have to open the device and test for ENXIO, because * the device nodes themselves will exist in the appliance. */ int device_name_translation (char *device, const char *func) { int fd; fd = open (device, O_RDONLY); if (fd >= 0) { close (fd); return 0; } if (errno != ENXIO && errno != ENOENT) { error: reply_with_perror ("%s: %s", func, device); return -1; } /* If the name begins with "/dev/sd" then try the alternatives. */ if (strncmp (device, "/dev/sd", 7) != 0) goto error; device[5] = 'h'; /* /dev/hd (old IDE driver) */ fd = open (device, O_RDONLY); if (fd >= 0) { close (fd); return 0; } device[5] = 'v'; /* /dev/vd (for virtio devices) */ fd = open (device, O_RDONLY); if (fd >= 0) { close (fd); return 0; } device[5] = 's'; /* Restore original device name. */ goto error; } /* LVM and other commands aren't synchronous, especially when udev is * involved. eg. You can create or remove some device, but the /dev * device node won't appear until some time later. This means that * you get an error if you run one command followed by another. * Use 'udevadm settle' after certain commands, but don't be too * fussed if it fails. */ void udev_settle (void) { command (NULL, NULL, "/sbin/udevadm", "settle", NULL); }