- FILE *fp;
- char *command;
- int maxsize = *datalen;
- char *localbuf;
-
- command = dupprintf("xauth list %s 2>/dev/null", display);
- fp = popen(command, "r");
- sfree(command);
-
- if (!fp)
- return; /* assume no auth */
-
- localbuf = smalloc(maxsize);
-
- while (1) {
- /*
- * Read a line from stdin, and attempt to parse it into a
- * display name (ignored), auth protocol, and auth string.
- */
- int c, i, hexdigit, proto;
- char protoname[64];
-
- /* Skip the display name. */
- while (c = getc(fp), c != EOF && c != '\n' && !isspace(c));
- if (c == EOF) break;
- if (c == '\n') continue;
-
- /* Skip white space. */
- while (c != EOF && c != '\n' && isspace(c))
- c = getc(fp);
- if (c == EOF) break;
- if (c == '\n') continue;
-
- /* Read the auth protocol name, and see if it matches any we
- * know about. */
- i = 0;
- while (c != EOF && c != '\n' && !isspace(c)) {
- if (i < lenof(protoname)-1) protoname[i++] = c;
- c = getc(fp);
- }
- protoname[i] = '\0';
-
- for (i = X11_NO_AUTH; ++i < X11_NAUTHS ;) {
- if (!strcmp(protoname, x11_authnames[i]))
- break;
- }
- if (i >= X11_NAUTHS || i <= proto) {
- /* Unrecognised protocol name, or a worse one than we already have.
- * Skip this line. */
- while (c != EOF && c != '\n')
- c = getc(fp);
- if (c == EOF) break;
- }
- proto = i;
-
- /* Skip white space. */
- while (c != EOF && c != '\n' && isspace(c))
- c = getc(fp);
- if (c == EOF) break;
- if (c == '\n') continue;
-
- /*
- * Now grab pairs of hex digits and shove them into `data'.
- */
- i = 0;
- hexdigit = -1;
- while (c != EOF && c != '\n') {
- int hexval = -1;
- if (c >= 'A' && c <= 'F')
- hexval = c + 10 - 'A';
- if (c >= 'a' && c <= 'f')
- hexval = c + 10 - 'a';
- if (c >= '0' && c <= '9')
- hexval = c - '0';
- if (hexval >= 0) {
- if (hexdigit >= 0) {
- hexdigit = (hexdigit << 4) + hexval;
- if (i < maxsize)
- localbuf[i++] = hexdigit;
- hexdigit = -1;
- } else
- hexdigit = hexval;
- }
- c = getc(fp);
- }
-
- *datalen = i;
- *protocol = proto;
- memcpy(data, localbuf, i);