more informative errors
diff --git a/libtelnet.c b/libtelnet.c
index 544c0ef..22fd42f 100644
--- a/libtelnet.c
+++ b/libtelnet.c
@@ -11,6 +11,10 @@
#include <malloc.h>
#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdarg.h>
#ifdef HAVE_ZLIB
#include "zlib.h"
@@ -18,6 +22,19 @@
#include "libtelnet.h"
+#ifdef ERROR
+# undef ERROR
+#endif
+
+#define ERROR(telnet, code, user_data, msg) \
+ _error(telnet, __FILE__, __LINE__, code, user_data, "%s", msg)
+#define ERROR_NOMEM(telnet, user_data, msg) \
+ _error(telnet, __FILE__, __LINE__, LIBTELNET_ERROR_NOMEM, user_data, \
+ "%s: %s", msg, strerror(errno))
+#define ERROR_ZLIB(telnet, user_data, rs, msg) \
+ _error(telnet, __FILE__, __LINE__, LIBTELNET_ERROR_UNKNOWN, \
+ user_data, "%s: %s", msg, zError(rs))
+
/* buffer sizes */
static const unsigned int _buffer_sizes[] = {
0,
@@ -29,6 +46,30 @@
static const unsigned int _buffer_sizes_count =
sizeof(_buffer_sizes) / sizeof(_buffer_sizes[0]);
+/* error generation function */
+static void _error(struct libtelnet_t *telnet, const char *file, unsigned line,
+ enum libtelnet_error_t err, void *user_data, const char *fmt, ...) {
+ char buffer[512];
+ va_list va;
+
+ /* format error intro */
+ snprintf(buffer, sizeof(buffer), "%s:%u: ",
+ file, line);
+
+ va_start(va, fmt);
+ vsnprintf(buffer + strlen(buffer), sizeof(buffer) - strlen(buffer),
+ fmt, va);
+ va_end(va);
+
+ /* invoke user's custom error handler if possible; otherwise,
+ * print to stderr
+ */
+ if (telnet->cb->error)
+ telnet->cb->error(telnet, err, buffer, user_data);
+ else
+ fprintf(stderr, "**ERROR**: libtelnet: %s\n", buffer);
+}
+
/* initialize a telnet state tracker */
void libtelnet_init(struct libtelnet_t *telnet, struct libtelnet_cb_t *cb,
enum libtelnet_mode_t mode) {
@@ -59,8 +100,8 @@
}
/* push a byte into the telnet buffer */
-static enum libtelnet_error_t _buffer_byte(
- struct libtelnet_t *telnet, unsigned char byte, void *user_data) {
+static enum libtelnet_error_t _buffer_byte(struct libtelnet_t *telnet,
+ unsigned char byte, void *user_data) {
unsigned char *new_buffer;
int i;
@@ -74,7 +115,8 @@
/* overflow -- can't grow any more */
if (i >= _buffer_sizes_count - 1) {
- telnet->cb->error(telnet, LIBTELNET_ERROR_OVERFLOW, user_data);
+ _error(telnet, __FILE__, __LINE__, LIBTELNET_ERROR_OVERFLOW,
+ user_data, "subnegotiation buffer size limit reached");
libtelnet_free(telnet);
return LIBTELNET_ERROR_OVERFLOW;
}
@@ -83,8 +125,7 @@
new_buffer = (unsigned char *)realloc(telnet->buffer,
_buffer_sizes[i + 1]);
if (new_buffer == 0) {
- telnet->cb->error(telnet, LIBTELNET_ERROR_NOMEM,
- user_data);
+ ERROR_NOMEM(telnet, user_data, "realloc() failed");
libtelnet_free(telnet);
return LIBTELNET_ERROR_NOMEM;
}
@@ -197,8 +238,8 @@
/* zero-size buffer is a protocol error */
if (telnet->length == 0) {
- telnet->cb->error(telnet, LIBTELNET_ERROR_PROTOCOL,
- user_data);
+ ERROR(telnet, LIBTELNET_ERROR_PROTOCOL, user_data,
+ "subnegotiation has zero data");
break;
}
@@ -214,20 +255,21 @@
*/
if (telnet->mode == LIBTELNET_MODE_CLIENT &&
telnet->buffer[0] == LIBTELNET_TELOPT_COMPRESS2) {
+ int rs;
+
/* allocate zstream box */
if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream)))
== 0) {
- telnet->cb->error(telnet,
- LIBTELNET_ERROR_NOMEM, user_data);
+ ERROR_NOMEM(telnet, user_data, "malloc() failed");
}
/* initialize */
memset(telnet->zlib, 0, sizeof(z_stream));
- if (inflateInit(telnet->zlib) != Z_OK) {
+ if ((rs = inflateInit(telnet->zlib)) != Z_OK) {
free(telnet->zlib);
telnet->zlib = 0;
- telnet->cb->error(telnet,
- LIBTELNET_ERROR_UNKNOWN, user_data);
+ ERROR_ZLIB(telnet, user_data, rs,
+ "inflateInit() failed");
break;
}
@@ -260,8 +302,9 @@
break;
/* something else -- protocol error */
default:
- telnet->cb->error(telnet, LIBTELNET_ERROR_PROTOCOL,
- user_data);
+ _error(telnet, __FILE__, __LINE__, LIBTELNET_ERROR_PROTOCOL,
+ user_data, "unexpected byte after IAC inside SB: %d",
+ byte);
start = i + 1;
telnet->state = LIBTELNET_STATE_DATA;
break;
@@ -304,8 +347,7 @@
_process(telnet, inflate_buffer, sizeof(inflate_buffer) -
telnet->zlib->avail_out, user_data);
else
- telnet->cb->error(telnet, LIBTELNET_ERROR_UNKNOWN,
- user_data);
+ ERROR_ZLIB(telnet, user_data, rs, "inflate() failed");
/* prepare output buffer for next run */
telnet->zlib->next_out = inflate_buffer;
@@ -336,6 +378,7 @@
*/
if (telnet->mode == LIBTELNET_MODE_SERVER && telnet->zlib != 0) {
unsigned char deflate_buffer[1024];
+ int rs;
/* initialize zlib state */
telnet->zlib->next_in = buffer;
@@ -345,12 +388,9 @@
/* deflate until buffer exhausted and all output is produced */
while (telnet->zlib->avail_in > 0 || telnet->zlib->avail_out == 0) {
- /* reset output buffer */
-
/* compress */
- if (deflate(telnet->zlib, Z_SYNC_FLUSH) != Z_OK) {
- telnet->cb->error(telnet, LIBTELNET_ERROR_UNKNOWN,
- user_data);
+ if ((rs = deflate(telnet->zlib, Z_SYNC_FLUSH)) != Z_OK) {
+ ERROR_ZLIB(telnet, user_data, rs, "deflate() failed");
deflateEnd(telnet->zlib);
free(telnet->zlib);
telnet->zlib = 0;
@@ -422,20 +462,21 @@
*/
if (telnet->mode == LIBTELNET_MODE_SERVER && opt ==
LIBTELNET_TELOPT_COMPRESS2) {
+ int rs;
+
/* allocate zstream box */
- if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream)))
- == 0) {
- telnet->cb->error(telnet,
- LIBTELNET_ERROR_NOMEM, user_data);
+ if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream))) == 0) {
+ ERROR_NOMEM(telnet, user_data, "malloc() failed");
+ return;
}
/* initialize */
memset(telnet->zlib, 0, sizeof(z_stream));
- if (deflateInit(telnet->zlib, Z_DEFAULT_COMPRESSION) != Z_OK) {
+ if ((rs = deflateInit(telnet->zlib, Z_DEFAULT_COMPRESSION)) != Z_OK) {
free(telnet->zlib);
telnet->zlib = 0;
- telnet->cb->error(telnet,
- LIBTELNET_ERROR_UNKNOWN, user_data);
+ ERROR_ZLIB(telnet, user_data, rs, "delateInit() failed");
+ return;
}
/* notify app that compression was enabled */
diff --git a/libtelnet.h b/libtelnet.h
index 821839f..693d065 100644
--- a/libtelnet.h
+++ b/libtelnet.h
@@ -115,24 +115,23 @@
/* libtelnet callback declarations */
struct libtelnet_cb_t {
/* received (processed) data */
- void (*data)(struct libtelnet_t *telnet,
- unsigned char *buffer, unsigned int size, void *user_data);
+ void (*data)(struct libtelnet_t *telnet, unsigned char *buffer,
+ unsigned int size, void *user_data);
/* processed data to buffer for sending */
- void (*send)(struct libtelnet_t *telnet,
- unsigned char *buffer, unsigned int size, void *user_data);
+ void (*send)(struct libtelnet_t *telnet, unsigned char *buffer,
+ unsigned int size, void *user_data);
/* unknown command notification */
- void (*command)(struct libtelnet_t *telnet,
- unsigned char cmd, void *user_data);
- /* negotiation notification */
- void (*negotiate)(struct libtelnet_t *telnet,
- unsigned char cmd, unsigned char opt, void *user_data);
- /* unknown subnegotiation notification */
- void (*subnegotiation)(struct libtelnet_t *telnet,
- unsigned char opt, unsigned char *data, unsigned int size,
+ void (*command)(struct libtelnet_t *telnet, unsigned char cmd,
void *user_data);
+ /* negotiation notification */
+ void (*negotiate)(struct libtelnet_t *telnet, unsigned char cmd,
+ unsigned char opt, void *user_data);
+ /* unknown subnegotiation notification */
+ void (*subnegotiation)(struct libtelnet_t *telnet, unsigned char opt,
+ unsigned char *data, unsigned int size, void *user_data);
/* error handler */
- void (*error)(struct libtelnet_t *telnet,
- enum libtelnet_error_t error, void *user_data);
+ void (*error)(struct libtelnet_t *telnet, enum libtelnet_error_t error,
+ const char *msg, void *user_data);
#ifdef HAVE_ZLIB
void (*compress)(struct libtelnet_t *telnet,
diff --git a/telnet-proxy.c b/telnet-proxy.c
index 8179253..4b8b13f 100644
--- a/telnet-proxy.c
+++ b/telnet-proxy.c
@@ -208,11 +208,11 @@
printf("%s COMPRESSION %s\e[0m\n", conn->name, enabled ? "ON" : "OFF");
}
-static void _error_cb(struct libtelnet_t *telnet,
- enum libtelnet_error_t error, void *user_data) {
+static void _error_cb(struct libtelnet_t *telnet, enum libtelnet_error_t error,
+ const char *msg, void *user_data) {
struct conn_t *conn = (struct conn_t*)user_data;
- printf("%s ERROR: %d\e[0m\n", conn->name, (int)error);
+ printf("%s ERROR: %s\e[0m\n", conn->name, msg);
exit(1);
}