+ return NULL;
+ }
+
+ /* Read up to GUESTFS_MESSAGE_MAX - <overhead> bytes. If it's
+ * larger than that, we need to return an error instead (for
+ * correctness).
+ */
+ max = GUESTFS_MESSAGE_MAX - 1000;
+ buf = NULL;
+ size = alloc = 0;
+
+ for (;;) {
+ if (size >= alloc) {
+ alloc += 8192;
+ if (alloc > max) {
+ reply_with_error ("cat: %s: file is too large for message buffer",
+ path);
+ free (buf);
+ close (fd);
+ return NULL;
+ }
+ buf2 = realloc (buf, alloc);
+ if (buf2 == NULL) {
+ reply_with_perror ("realloc");
+ free (buf);
+ close (fd);
+ return NULL;
+ }
+ buf = buf2;
+ }
+
+ r = read (fd, buf + size, alloc - size);
+ if (r == -1) {
+ reply_with_perror ("read: %s", path);
+ free (buf);
+ close (fd);
+ return NULL;
+ }
+ if (r == 0) {
+ buf[size] = '\0';
+ break;
+ }
+ if (r > 0)
+ size += r;
+ }
+
+ if (close (fd) == -1) {
+ reply_with_perror ("close: %s", path);
+ free (buf);
+ return NULL;
+ }
+
+ return buf; /* caller will free */
+}
+
+char **
+do_read_lines (const char *path)
+{
+ char **r = NULL;
+ int size = 0, alloc = 0;
+ FILE *fp;
+ char *line = NULL;
+ size_t len = 0;
+ ssize_t n;
+
+ NEED_ROOT (NULL);
+ ABS_PATH (path, NULL);
+
+ CHROOT_IN;
+ fp = fopen (path, "r");
+ CHROOT_OUT;
+
+ if (!fp) {
+ reply_with_perror ("fopen: %s", path);
+ return NULL;
+ }
+
+ while ((n = getline (&line, &len, fp)) != -1) {
+ /* Remove either LF or CRLF. */
+ if (n >= 2 && line[n-2] == '\r' && line[n-1] == '\n')
+ line[n-2] = '\0';
+ else if (n >= 1 && line[n-1] == '\n')
+ line[n-1] = '\0';
+
+ if (add_string (&r, &size, &alloc, line) == -1) {
+ free (line);
+ fclose (fp);
+ return NULL;
+ }
+ }
+
+ free (line);
+
+ if (add_string (&r, &size, &alloc, NULL) == -1) {
+ fclose (fp);
+ return NULL;
+ }
+
+ if (fclose (fp) == EOF) {
+ reply_with_perror ("fclose: %s", path);
+ free_strings (r);
+ return NULL;
+ }
+
+ return r;
+}
+
+int
+do_rm (const char *path)
+{
+ int r;
+
+ NEED_ROOT (-1);
+ ABS_PATH (path, -1);
+
+ CHROOT_IN;
+ r = unlink (path);
+ CHROOT_OUT;
+
+ if (r == -1) {
+ reply_with_perror ("unlink: %s", path);