From c26b55a06e50736567802922563e996a918e8c6c Mon Sep 17 00:00:00 2001
From: s3lph <s3lph@kabelsalat.ch>
Date: Sat, 30 Nov 2024 14:13:36 +0100
Subject: [PATCH] feat: improved error handling

---
 honeywell-config.c | 74 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 51 insertions(+), 23 deletions(-)

diff --git a/honeywell-config.c b/honeywell-config.c
index 657319d..e49c598 100644
--- a/honeywell-config.c
+++ b/honeywell-config.c
@@ -8,6 +8,17 @@
 #include <libusb-1.0/libusb.h>
 
 
+#define S_ENQ 0x05
+#define S_ACK 0x06
+#define S_NAK 0x15
+
+#define USBERR(msg, rc) { dprintf(2, "%s: %s\n", msg, libusb_strerror(rc)); }
+#define DEBUG(...) { if (debug >= 1) { dprintf(2, __VA_ARGS__); } }
+#define DEBUG2(...) { if (debug >= 2) { dprintf(2, __VA_ARGS__); } }
+#define DEBUG3(...) { if (debug >= 3) { dprintf(2, __VA_ARGS__); } }
+#define HEXBUF(msg, buf, n) { if (debug >= 3) { dprintf(2, "%s:", msg); for (uint8_t *__h = buf; __h < buf+n;++__h) { dprintf(2, " %02x", *__h); } dprintf(2, "\n"); } }
+
+
 uint16_t vendor_id = 0;
 uint16_t product_id = 0;
 uint8_t reset = 0;
@@ -20,12 +31,6 @@ uint8_t explicit_in = 0;
 libusb_device_handle *devh = NULL;
 uint8_t endpoint = 0;
 
-#define USBERR(msg, rc) { dprintf(2, "%s: %s\n", msg, libusb_strerror(rc)); }
-#define DEBUG(...) { if (debug >= 1) { dprintf(2, __VA_ARGS__); } }
-#define DEBUG2(...) { if (debug >= 2) { dprintf(2, __VA_ARGS__); } }
-#define DEBUG3(...) { if (debug >= 3) { dprintf(2, __VA_ARGS__); } }
-#define HEXBUF(msg, buf, n) { if (debug >= 3) { dprintf(2, "%s:", msg); for (uint8_t *__h = buf; __h < buf+n;++__h) { dprintf(2, " %02x", *__h); } dprintf(2, "\n"); } }
-
 
 uint32_t vidpid[] = {
   0x0c2e0b01,
@@ -38,14 +43,16 @@ struct tokenizer {
   char tokbuf[1024];
   char *tok;
   uint8_t eot;
-  int (*cb)(const char *tok, uint8_t last);
+  uint8_t status;
+  int (*cb)(const char *, uint8_t , uint8_t);
 };
 
 
-void tok_init(struct tokenizer *t, int (*cb)(const char *tok, uint8_t last)) {
+void tok_init(struct tokenizer *t, int (*cb)(const char *, uint8_t, uint8_t)) {
   memset(t->tokbuf, 0, 1024);
   t->tok = t->tokbuf;
   t->eot = 0;
+  t->status = 0;
   t->cb = cb;
 }
 
@@ -63,14 +70,16 @@ int tok_read(struct tokenizer *t, char *buf, size_t n) {
     }
     if (end) {
       if (end > start) {
-	for (char *c = start; c < end; ++c) {
+	for (char *c = start; c < end < buf+n; ++c) {
 	  if (isprint(*c)) {
 	    *(t->tok++) = *c;
+	  } else {
+	    t->status = *c;
 	  }
 	}
       }
       *(t->tok) = 0;
-      if (t->cb(t->tokbuf, t->eot)) {
+      if (t->cb(t->tokbuf, t->status, t->eot)) {
 	return 1;
       }
       t->tok = t->tokbuf;
@@ -86,6 +95,8 @@ int tok_read(struct tokenizer *t, char *buf, size_t n) {
     for (char *c = start; *c != 0; ++c) {
       if (isprint(*c)) {
 	*(t->tok++) = *c;
+      } else {
+	t->status = *c;
       }
     }
     *(t->tok) = 0;
@@ -99,28 +110,45 @@ struct tokenizer in_tok;
 struct tokenizer out_tok;
 
 
-int print_token(const char *tok, uint8_t last) {
-  int rc;
-  if (oneline && !last) {
-    rc = dprintf(outfd, "%s;", tok);
-  } else {
-    rc = dprintf(outfd, "%s.\n", tok);
+int print_token(const char *tok, uint8_t status, uint8_t last) {
+  switch (status) {
+  case S_ACK:
+    int rc;
+    if (oneline && !last) {
+      rc = dprintf(outfd, "%s;", tok);
+    } else {
+      rc = dprintf(outfd, "%s.\n", tok);
+    }
+    return rc < 0;
+  case S_ENQ:
+    dprintf(2, "command not recognized by device: %s\n", tok);
+    return 1;
+  case S_NAK:
+    dprintf(2, "command data out of bounds: %s\n", tok);
+    return 1;
+  default:
+    dprintf(2, "device responded to command %s with unknown status 0x%02x\n", tok, status);
+    return 1;
   }
-  return rc < 0;
 }
 
 
-int send_token(const char *tok, uint8_t last) {
+int send_token(const char *tok, uint8_t status, uint8_t last) {
   in_tok.eot = 0;
-  uint8_t cmd[64] = { 0 };
+  uint8_t cmd[65] = { 0 };
+  uint8_t *cmdend = cmd + 64;
   uint8_t *cmdptr = cmd + 5;
   int rc;
-  memset(cmdptr, 0, 59);
-  for (uint8_t i = 0; i < strlen(tok); ++i) {
+  memset(cmdptr, 0, 60);
+  for (uint8_t i = 0; i < strlen(tok) && cmdptr < cmdend; ++i) {
     if (isprint(tok[i])) {
       *(cmdptr++) = tok[i];
     }
   }
+  if (cmdptr >= cmdend) {
+    dprintf(2, "token too long: %s\n", tok);
+    return 1;
+  }
   *cmdptr = '.';
   cmd[0] = 0xfd;
   cmd[1] = cmdptr - cmd - 1;
@@ -159,7 +187,7 @@ int config(int argc, char **args) {
   // If commands are provided on the CLI, execute only those
   if (argc > 0) {
     for (int i = 0; i < argc; ++i) {
-      if (send_token(args[i], i >= argc-1)) {
+      if (send_token(args[i], S_ACK, i >= argc-1)) {
 	return 1;
       }
     }
@@ -168,7 +196,7 @@ int config(int argc, char **args) {
   // If input is a tty, dump config
   // Can be overwritten with "-i -" on the cli
   if (isatty(infd) && !explicit_in) {
-    return send_token("?", 1);
+    return send_token("?", S_ACK, 1);
   }
   // Otherwhise parse tokens from stdin
   char buf[65];