osmocom
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libtelnet
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more informative errors

This commit is contained in:
Sean Middleditch 2009-03-14 22:35:01 -04:00
parent 3032302674
commit d922c6f7e0
3 changed files with 85 additions and 45 deletions
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97
libtelnet.c
View File

@ -11,6 +11,10 @@
#include <malloc.h> #include <malloc.h>
#include <string.h> #include <string.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdarg.h>
#ifdef HAVE_ZLIB #ifdef HAVE_ZLIB
#include "zlib.h" #include "zlib.h"
@ -18,6 +22,19 @@
#include "libtelnet.h" #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 */ /* buffer sizes */
static const unsigned int _buffer_sizes[] = { static const unsigned int _buffer_sizes[] = {
0, 0,
@ -29,6 +46,30 @@ static const unsigned int _buffer_sizes[] = {
static const unsigned int _buffer_sizes_count = static const unsigned int _buffer_sizes_count =
sizeof(_buffer_sizes) / sizeof(_buffer_sizes[0]); 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 */ /* initialize a telnet state tracker */
void libtelnet_init(struct libtelnet_t *telnet, struct libtelnet_cb_t *cb, void libtelnet_init(struct libtelnet_t *telnet, struct libtelnet_cb_t *cb,
enum libtelnet_mode_t mode) { enum libtelnet_mode_t mode) {
@ -59,8 +100,8 @@ void libtelnet_free(struct libtelnet_t *telnet) {
} }
/* push a byte into the telnet buffer */ /* push a byte into the telnet buffer */
static enum libtelnet_error_t _buffer_byte( static enum libtelnet_error_t _buffer_byte(struct libtelnet_t *telnet,
struct libtelnet_t *telnet, unsigned char byte, void *user_data) { unsigned char byte, void *user_data) {
unsigned char *new_buffer; unsigned char *new_buffer;
int i; int i;
@ -74,7 +115,8 @@ static enum libtelnet_error_t _buffer_byte(
/* overflow -- can't grow any more */ /* overflow -- can't grow any more */
if (i >= _buffer_sizes_count - 1) { 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); libtelnet_free(telnet);
return LIBTELNET_ERROR_OVERFLOW; return LIBTELNET_ERROR_OVERFLOW;
} }
@ -83,8 +125,7 @@ static enum libtelnet_error_t _buffer_byte(
new_buffer = (unsigned char *)realloc(telnet->buffer, new_buffer = (unsigned char *)realloc(telnet->buffer,
_buffer_sizes[i + 1]); _buffer_sizes[i + 1]);
if (new_buffer == 0) { if (new_buffer == 0) {
telnet->cb->error(telnet, LIBTELNET_ERROR_NOMEM, ERROR_NOMEM(telnet, user_data, "realloc() failed");
user_data);
libtelnet_free(telnet); libtelnet_free(telnet);
return LIBTELNET_ERROR_NOMEM; return LIBTELNET_ERROR_NOMEM;
} }
@ -197,8 +238,8 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
/* zero-size buffer is a protocol error */ /* zero-size buffer is a protocol error */
if (telnet->length == 0) { if (telnet->length == 0) {
telnet->cb->error(telnet, LIBTELNET_ERROR_PROTOCOL, ERROR(telnet, LIBTELNET_ERROR_PROTOCOL, user_data,
user_data); "subnegotiation has zero data");
break; break;
} }
@ -214,20 +255,21 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
*/ */
if (telnet->mode == LIBTELNET_MODE_CLIENT && if (telnet->mode == LIBTELNET_MODE_CLIENT &&
telnet->buffer[0] == LIBTELNET_TELOPT_COMPRESS2) { telnet->buffer[0] == LIBTELNET_TELOPT_COMPRESS2) {
int rs;
/* allocate zstream box */ /* allocate zstream box */
if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream))) if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream)))
== 0) { == 0) {
telnet->cb->error(telnet, ERROR_NOMEM(telnet, user_data, "malloc() failed");
LIBTELNET_ERROR_NOMEM, user_data);
} }
/* initialize */ /* initialize */
memset(telnet->zlib, 0, sizeof(z_stream)); memset(telnet->zlib, 0, sizeof(z_stream));
if (inflateInit(telnet->zlib) != Z_OK) { if ((rs = inflateInit(telnet->zlib)) != Z_OK) {
free(telnet->zlib); free(telnet->zlib);
telnet->zlib = 0; telnet->zlib = 0;
telnet->cb->error(telnet, ERROR_ZLIB(telnet, user_data, rs,
LIBTELNET_ERROR_UNKNOWN, user_data); "inflateInit() failed");
break; break;
} }
@ -260,8 +302,9 @@ static void _process(struct libtelnet_t *telnet, unsigned char *buffer,
break; break;
/* something else -- protocol error */ /* something else -- protocol error */
default: default:
telnet->cb->error(telnet, LIBTELNET_ERROR_PROTOCOL, _error(telnet, __FILE__, __LINE__, LIBTELNET_ERROR_PROTOCOL,
user_data); user_data, "unexpected byte after IAC inside SB: %d",
byte);
start = i + 1; start = i + 1;
telnet->state = LIBTELNET_STATE_DATA; telnet->state = LIBTELNET_STATE_DATA;
break; break;
@ -304,8 +347,7 @@ void libtelnet_push(struct libtelnet_t *telnet, unsigned char *buffer,
_process(telnet, inflate_buffer, sizeof(inflate_buffer) - _process(telnet, inflate_buffer, sizeof(inflate_buffer) -
telnet->zlib->avail_out, user_data); telnet->zlib->avail_out, user_data);
else else
telnet->cb->error(telnet, LIBTELNET_ERROR_UNKNOWN, ERROR_ZLIB(telnet, user_data, rs, "inflate() failed");
user_data);
/* prepare output buffer for next run */ /* prepare output buffer for next run */
telnet->zlib->next_out = inflate_buffer; telnet->zlib->next_out = inflate_buffer;
@ -336,6 +378,7 @@ static void _send(struct libtelnet_t *telnet, unsigned char *buffer,
*/ */
if (telnet->mode == LIBTELNET_MODE_SERVER && telnet->zlib != 0) { if (telnet->mode == LIBTELNET_MODE_SERVER && telnet->zlib != 0) {
unsigned char deflate_buffer[1024]; unsigned char deflate_buffer[1024];
int rs;
/* initialize zlib state */ /* initialize zlib state */
telnet->zlib->next_in = buffer; telnet->zlib->next_in = buffer;
@ -345,12 +388,9 @@ static void _send(struct libtelnet_t *telnet, unsigned char *buffer,
/* deflate until buffer exhausted and all output is produced */ /* deflate until buffer exhausted and all output is produced */
while (telnet->zlib->avail_in > 0 || telnet->zlib->avail_out == 0) { while (telnet->zlib->avail_in > 0 || telnet->zlib->avail_out == 0) {
/* reset output buffer */
/* compress */ /* compress */
if (deflate(telnet->zlib, Z_SYNC_FLUSH) != Z_OK) { if ((rs = deflate(telnet->zlib, Z_SYNC_FLUSH)) != Z_OK) {
telnet->cb->error(telnet, LIBTELNET_ERROR_UNKNOWN, ERROR_ZLIB(telnet, user_data, rs, "deflate() failed");
user_data);
deflateEnd(telnet->zlib); deflateEnd(telnet->zlib);
free(telnet->zlib); free(telnet->zlib);
telnet->zlib = 0; telnet->zlib = 0;
@ -422,20 +462,21 @@ void libtelnet_send_subnegotiation(struct libtelnet_t *telnet,
*/ */
if (telnet->mode == LIBTELNET_MODE_SERVER && opt == if (telnet->mode == LIBTELNET_MODE_SERVER && opt ==
LIBTELNET_TELOPT_COMPRESS2) { LIBTELNET_TELOPT_COMPRESS2) {
int rs;
/* allocate zstream box */ /* allocate zstream box */
if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream))) if ((telnet->zlib = (z_stream *)malloc(sizeof(z_stream))) == 0) {
== 0) { ERROR_NOMEM(telnet, user_data, "malloc() failed");
telnet->cb->error(telnet, return;
LIBTELNET_ERROR_NOMEM, user_data);
} }
/* initialize */ /* initialize */
memset(telnet->zlib, 0, sizeof(z_stream)); 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); free(telnet->zlib);
telnet->zlib = 0; telnet->zlib = 0;
telnet->cb->error(telnet, ERROR_ZLIB(telnet, user_data, rs, "delateInit() failed");
LIBTELNET_ERROR_UNKNOWN, user_data); return;
} }
/* notify app that compression was enabled */ /* notify app that compression was enabled */

27
libtelnet.h
View File

@ -115,24 +115,23 @@ enum libtelnet_error_t {
/* libtelnet callback declarations */ /* libtelnet callback declarations */
struct libtelnet_cb_t { struct libtelnet_cb_t {
/* received (processed) data */ /* received (processed) data */
void (*data)(struct libtelnet_t *telnet, void (*data)(struct libtelnet_t *telnet, unsigned char *buffer,
unsigned char *buffer, unsigned int size, void *user_data); unsigned int size, void *user_data);
/* processed data to buffer for sending */ /* processed data to buffer for sending */
void (*send)(struct libtelnet_t *telnet, void (*send)(struct libtelnet_t *telnet, unsigned char *buffer,
unsigned char *buffer, unsigned int size, void *user_data); unsigned int size, void *user_data);
/* unknown command notification */ /* unknown command notification */
void (*command)(struct libtelnet_t *telnet, void (*command)(struct libtelnet_t *telnet, unsigned char cmd,
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); 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 */ /* error handler */
void (*error)(struct libtelnet_t *telnet, void (*error)(struct libtelnet_t *telnet, enum libtelnet_error_t error,
enum libtelnet_error_t error, void *user_data); const char *msg, void *user_data);
#ifdef HAVE_ZLIB #ifdef HAVE_ZLIB
void (*compress)(struct libtelnet_t *telnet, void (*compress)(struct libtelnet_t *telnet,

6
telnet-proxy.c
View File

@ -208,11 +208,11 @@ static void _compress_cb(struct libtelnet_t *telnet, char enabled,
printf("%s COMPRESSION %s\e[0m\n", conn->name, enabled ? "ON" : "OFF"); printf("%s COMPRESSION %s\e[0m\n", conn->name, enabled ? "ON" : "OFF");
} }
static void _error_cb(struct libtelnet_t *telnet, static void _error_cb(struct libtelnet_t *telnet, enum libtelnet_error_t error,
enum libtelnet_error_t error, void *user_data) { const char *msg, void *user_data) {
struct conn_t *conn = (struct conn_t*)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); exit(1);
} }