+
+char *
+do_read_file (const char *path, size_t *size_r)
+{
+ int fd;
+ struct stat statbuf;
+ char *r;
+
+ CHROOT_IN;
+ fd = open (path, O_RDONLY);
+ CHROOT_OUT;
+
+ if (fd == -1) {
+ reply_with_perror ("open: %s", path);
+ return NULL;
+ }
+
+ if (fstat (fd, &statbuf) == -1) {
+ reply_with_perror ("fstat: %s", path);
+ close (fd);
+ return NULL;
+ }
+
+ /* The actual limit on messages is smaller than this. This
+ * check just limits the amount of memory we'll try and allocate
+ * here. If the message is larger than the real limit, that will
+ * be caught later when we try to serialize the message.
+ */
+ if (statbuf.st_size >= GUESTFS_MESSAGE_MAX) {
+ reply_with_error ("%s: file is too large for the protocol, use guestfs_download instead", path);
+ close (fd);
+ return NULL;
+ }
+ r = malloc (statbuf.st_size);
+ if (r == NULL) {
+ reply_with_perror ("malloc");
+ close (fd);
+ return NULL;
+ }
+
+ if (xread (fd, r, statbuf.st_size) == -1) {
+ reply_with_perror ("read: %s", path);
+ close (fd);
+ free (r);
+ return NULL;
+ }
+
+ if (close (fd) == -1) {
+ reply_with_perror ("close: %s", path);
+ free (r);
+ return NULL;
+ }
+
+ /* Mustn't touch *size_r until we are sure that we won't return any
+ * error (RHBZ#589039).
+ */
+ *size_r = statbuf.st_size;
+ return r;
+}
+
+static char *
+pread_fd (int fd, int count, int64_t offset, size_t *size_r,
+ const char *display_path)
+{
+ ssize_t r;
+ char *buf;
+
+ if (count < 0) {
+ reply_with_error ("count is negative");
+ close (fd);
+ return NULL;
+ }
+
+ if (offset < 0) {
+ reply_with_error ("offset is negative");
+ close (fd);
+ return NULL;
+ }
+
+ /* The actual limit on messages is smaller than this. This check
+ * just limits the amount of memory we'll try and allocate in the
+ * function. If the message is larger than the real limit, that
+ * will be caught later when we try to serialize the message.
+ */
+ if (count >= GUESTFS_MESSAGE_MAX) {
+ reply_with_error ("%s: count is too large for the protocol, use smaller reads", display_path);
+ close (fd);
+ return NULL;
+ }
+
+ buf = malloc (count);
+ if (buf == NULL) {
+ reply_with_perror ("malloc");
+ close (fd);
+ return NULL;
+ }
+
+ r = pread (fd, buf, count, offset);
+ if (r == -1) {
+ reply_with_perror ("pread: %s", display_path);
+ close (fd);
+ free (buf);
+ return NULL;
+ }
+
+ if (close (fd) == -1) {
+ reply_with_perror ("close: %s", display_path);
+ close (fd);
+ free (buf);
+ return NULL;
+ }
+
+ /* Mustn't touch *size_r until we are sure that we won't return any
+ * error (RHBZ#589039).
+ */
+ *size_r = r;
+ return buf;
+}
+
+char *
+do_pread (const char *path, int count, int64_t offset, size_t *size_r)
+{
+ int fd;
+
+ CHROOT_IN;
+ fd = open (path, O_RDONLY);
+ CHROOT_OUT;
+
+ if (fd == -1) {
+ reply_with_perror ("open: %s", path);
+ return NULL;
+ }
+
+ return pread_fd (fd, count, offset, size_r, path);
+}
+
+char *
+do_pread_device (const char *device, int count, int64_t offset, size_t *size_r)
+{
+ int fd = open (device, O_RDONLY);
+ if (fd == -1) {
+ reply_with_perror ("open: %s", device);
+ return NULL;
+ }
+
+ return pread_fd (fd, count, offset, size_r, device);
+}
+
+static int
+pwrite_fd (int fd, const char *content, size_t size, int64_t offset,
+ const char *display_path)
+{
+ ssize_t r;
+
+ r = pwrite (fd, content, size, offset);
+ if (r == -1) {
+ reply_with_perror ("pwrite: %s", display_path);
+ close (fd);
+ return -1;
+ }
+
+ if (close (fd) == -1) {
+ reply_with_perror ("close: %s", display_path);
+ close (fd);
+ return -1;
+ }
+
+ return r;
+}
+
+int
+do_pwrite (const char *path, const char *content, size_t size, int64_t offset)
+{
+ int fd;
+
+ if (offset < 0) {
+ reply_with_error ("offset is negative");
+ return -1;
+ }
+
+ CHROOT_IN;
+ fd = open (path, O_WRONLY);
+ CHROOT_OUT;
+
+ if (fd == -1) {
+ reply_with_perror ("open: %s", path);
+ return -1;
+ }
+
+ return pwrite_fd (fd, content, size, offset, path);
+}
+
+int
+do_pwrite_device (const char *device, const char *content, size_t size,
+ int64_t offset)
+{
+ if (offset < 0) {
+ reply_with_error ("offset is negative");
+ return -1;
+ }
+
+ int fd = open (device, O_WRONLY);
+ if (fd == -1) {
+ reply_with_perror ("open: %s", device);
+ return -1;
+ }
+
+ return pwrite_fd (fd, content, size, offset, device);
+}
+
+/* This runs the 'file' command. */
+char *
+do_file (const char *path)
+{
+ char *buf = NULL;
+ const char *display_path = path;
+
+ int is_dev = STRPREFIX (path, "/dev/");
+
+ if (!is_dev) {
+ buf = sysroot_path (path);
+ if (!buf) {
+ reply_with_perror ("malloc");
+ return NULL;
+ }
+ path = buf;
+
+ /* For non-dev, check this is a regular file, else just return the
+ * file type as a string (RHBZ#582484).
+ */
+ struct stat statbuf;
+ if (lstat (path, &statbuf) == -1) {
+ reply_with_perror ("lstat: %s", display_path);
+ free (buf);
+ return NULL;
+ }
+
+ if (! S_ISREG (statbuf.st_mode)) {
+ char *ret;
+
+ free (buf);
+
+ if (S_ISDIR (statbuf.st_mode))
+ ret = strdup ("directory");
+ else if (S_ISCHR (statbuf.st_mode))
+ ret = strdup ("character device");
+ else if (S_ISBLK (statbuf.st_mode))
+ ret = strdup ("block device");
+ else if (S_ISFIFO (statbuf.st_mode))
+ ret = strdup ("FIFO");
+ else if (S_ISLNK (statbuf.st_mode))
+ ret = strdup ("symbolic link");
+ else if (S_ISSOCK (statbuf.st_mode))
+ ret = strdup ("socket");
+ else
+ ret = strdup ("unknown, not regular file");
+
+ if (ret == NULL)
+ reply_with_perror ("strdup");
+ return ret;
+ }
+ }
+
+ /* Which flags to use? For /dev paths, follow links because
+ * /dev/VG/LV is a symbolic link.
+ */
+ const char *flags = is_dev ? "-zbsL" : "-zb";
+
+ char *out, *err;
+ int r = command (&out, &err, "file", flags, path, NULL);
+ free (buf);
+
+ if (r == -1) {
+ free (out);
+ reply_with_error ("%s: %s", display_path, err);
+ free (err);
+ return NULL;
+ }
+ free (err);
+
+ /* We need to remove the trailing \n from output of file(1). */
+ size_t len = strlen (out);
+ if (len > 0 && out[len-1] == '\n')
+ out[len-1] = '\0';
+
+ return out; /* caller frees */
+}
+
+/* zcat | file */
+char *
+do_zfile (const char *method, const char *path)
+{
+ int len;
+ const char *zcat;
+ char *cmd;
+ FILE *fp;
+ char line[256];
+
+ if (STREQ (method, "gzip") || STREQ (method, "compress"))
+ zcat = "zcat";
+ else if (STREQ (method, "bzip2"))
+ zcat = "bzcat";
+ else {
+ reply_with_error ("unknown method");
+ return NULL;
+ }
+
+ if (asprintf_nowarn (&cmd, "%s %R | file -bsL -", zcat, path) == -1) {
+ reply_with_perror ("asprintf");
+ return NULL;
+ }
+
+ if (verbose)
+ fprintf (stderr, "%s\n", cmd);
+
+ fp = popen (cmd, "r");
+ if (fp == NULL) {
+ reply_with_perror ("%s", cmd);
+ free (cmd);
+ return NULL;
+ }
+
+ free (cmd);
+
+ if (fgets (line, sizeof line, fp) == NULL) {
+ reply_with_perror ("fgets");
+ fclose (fp);
+ return NULL;
+ }
+
+ if (fclose (fp) == -1) {
+ reply_with_perror ("fclose");
+ return NULL;
+ }
+
+ len = strlen (line);
+ if (len > 0 && line[len-1] == '\n')
+ line[len-1] = '\0';
+
+ return strdup (line);
+}
+
+int64_t
+do_filesize (const char *path)
+{
+ int r;
+ struct stat buf;
+
+ CHROOT_IN;
+ r = stat (path, &buf); /* follow symlinks */
+ CHROOT_OUT;
+
+ if (r == -1) {
+ reply_with_perror ("%s", path);
+ return -1;
+ }
+
+ return buf.st_size;
+}