Well, it's not exactly safe, but I bet it'll do for now

src/kiss.c

@@ -0,0 +1,56 @@
+#include <patty/kiss.h>
+
+enum kiss_flags {
+    KISS_NONE   = 0x00,
+    KISS_FRAME  = 0x01,
+    KISS_ESCAPE = 0x02
+};
+
+int patty_kiss_read(int fd, void *buf, size_t *len, int *channel) {
+    int flags = KISS_NONE;
+    size_t i, b = 0;
+
+    *channel = 0;
+
+    for (i=0; i<PATTY_KISS_BUFLEN; i++) {
+        unsigned char c = ((char *)buf)[i];
+
+        if (flags & KISS_FRAME == 0) {
+            if (c == PATTY_KISS_FEND) {
+                flags |= KISS_FRAME;
+            }
+
+            continue;
+        }
+
+        if (flags & KISS_ESCAPE) {
+            if (c == PATTY_KISS_TFEND) {
+                ((char *)buf)[b++] = PATTY_KISS_FEND;
+            } else if (c == PATTY_KISS_TFESC) {
+                ((char *)buf)[b++] = PATTY_KISS_FESC;
+            }
+
+            flags &= ~KISS_ESCAPE;
+
+            continue;
+        }
+
+        if (flags & KISS_FRAME) {
+            if (c == PATTY_KISS_FESC) {
+                flags |= KISS_ESCAPE;
+
+                continue;
+            } else if (c == PATTY_KISS_FEND) {
+                flags &= ~KISS_FRAME;
+
+                break;
+            }
+
+            ((char *)buf)[b++] = c;
+        }
+    }
+
+    *len = b + 1;
+
+    return 0;
+}