+
+/* 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);
+}