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/*
* Copyright (c) 2016 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* This is a temporary helper library to seamlessly run against
* the current API as exposed by libpneum.
* In the future once the sync API is exposed as well as
* a way to free the received data, this can go away.
*/
#include <dlfcn.h>
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#include <stdlib.h>
#include <pthread.h>
pthread_mutex_t mut;
pthread_mutex_t *cb_lock = &mut;
void *pneum_handle = NULL;
typedef void* (*arbitrary)();
int (*orig_pneum_connect)(char *name, char *chroot_prefix) = NULL;
int (*orig_pneum_connect_sync)(char *name, char *chroot_prefix) = NULL;
int (*orig_pneum_disconnect)(void) = NULL;
int (*orig_pneum_read)(char **data, int *l) = NULL;
int (*orig_pneum_write)(char *data, int len) = NULL;
int (*orig_pneum_has_data)(void) = NULL;
int (*orig_pneum_data_free)(char *data) = NULL;
arbitrary my_function = NULL;
typedef uint8_t u8;
typedef uint32_t u32;
u8 *cough_read_buffer;
u32 cough_read_buffer_size = 1000000;
u32 cough_read_head = 0;
u32 cough_read_lock_start = 0; /* lock_start till head is busy memory */
u32 cough_read_tail = 0;
int wrap_pneum_callback(char *data, int len) {
// printf("Cough callback! with %d bytes\n", len);
pthread_mutex_lock(cb_lock);
if(cough_read_lock_start == cough_read_head) {
// printf("Reset read head!\n");
cough_read_head = 0;
cough_read_tail = 0;
cough_read_lock_start = 0;
}
u32 store_len = len;
memcpy(cough_read_buffer + cough_read_head, &store_len, sizeof(u32));
cough_read_head += sizeof(u32);
memcpy(cough_read_buffer + cough_read_head, data, len);
cough_read_head += len;
pthread_mutex_unlock(cb_lock);
return len;
}
int cough_pneum_attach(char *pneum_fname, char *cough_fname) {
/* this is needed to make the pneum aware of the wrap_pneum_callback */
pneum_handle = dlopen(cough_fname, RTLD_NOW|RTLD_GLOBAL);
/* now let's try to load pneum itself */
pneum_handle = dlopen(pneum_fname, RTLD_NOW|RTLD_GLOBAL);
if (pneum_handle) {
*(void**)(&orig_pneum_connect) = dlsym(pneum_handle,"pneum_connect");
*(void**)(&orig_pneum_connect_sync) = dlsym(pneum_handle,"pneum_connect_sync");
*(void**)(&orig_pneum_disconnect) = dlsym(pneum_handle,"pneum_disconnect");
*(void**)(&orig_pneum_read) = dlsym(pneum_handle,"pneum_read");
*(void**)(&orig_pneum_write) = dlsym(pneum_handle,"pneum_write");
*(void**)(&orig_pneum_has_data) = dlsym(pneum_handle,"pneum_has_data");
*(void**)(&orig_pneum_data_free) = dlsym(pneum_handle,"pneum_data_free");
// If you uncomment the below line we pretend we have an async-only libpneum
orig_pneum_connect_sync = NULL;
cough_read_buffer = malloc(cough_read_buffer_size);
} else {
printf("Could not get cough handle\n");
printf("Error: %s", dlerror());
return -1;
}
*(void**)(&my_function) = dlsym(pneum_handle,"something");
}
int pneum_connect(char *name, char *chroot_prefix) {
if(orig_pneum_connect) {
return(orig_pneum_connect(name, chroot_prefix));
} else {
printf("COUGH: pneum_connect\n");
return -1;
}
}
int pneum_connect_sync(char *name, char *chroot_prefix) {
if(orig_pneum_connect_sync) {
int ret = (orig_pneum_connect_sync(name, chroot_prefix));
return ret;
} else {
return(orig_pneum_connect(name, chroot_prefix));
}
}
int pneum_disconnect(void) {
if(orig_pneum_disconnect) {
return orig_pneum_disconnect();
} else {
printf("COUGH: pneum_disconnect\n");
return -1;
}
}
int pneum_has_data(void) {
if (orig_pneum_connect_sync) {
/* always return 1 in a pass-through case */
return 1;
} else {
// printf("COUGH: pneum_has_data\n");
return (cough_read_head != cough_read_tail);
}
}
int pneum_read(char **data, int *l) {
if(orig_pneum_connect_sync) {
return orig_pneum_read(data, l);
} else {
while(!pneum_has_data());
u32 n_bytes;
pthread_mutex_lock(cb_lock);
memcpy(&n_bytes, cough_read_buffer + cough_read_tail, sizeof(u32));
cough_read_tail += sizeof(u32);
void * dataptr = (void *) (cough_read_buffer + cough_read_tail);
*data = dataptr;
cough_read_tail += n_bytes;
*l = n_bytes;
pthread_mutex_unlock(cb_lock);
return n_bytes;
}
}
int pneum_write(char *data, int len) {
if(orig_pneum_write) {
return(orig_pneum_write(data, len));
} else {
printf("COUGH: pneum_write\n");
return -1;
}
}
void pneum_data_free(char *data) {
if (orig_pneum_connect_sync) {
if(orig_pneum_data_free) {
orig_pneum_data_free(data);
} else {
printf("COUGH: pneum_data_free\n");
}
} else {
u32 *len;
uint32_t index = ((u8*)data) - cough_read_buffer;
pthread_mutex_lock(cb_lock);
if ((index < cough_read_head) && (index > cough_read_lock_start)) {
len = (void *)(data - sizeof(u32));
cough_read_lock_start = index + *len;
}
pthread_mutex_unlock(cb_lock);
}
}
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