Luajit API and some examples

Change-Id: Ia140c4750f06870c40b7058c4afb2e20ca633a49
Signed-off-by: Andrew Yourtchenko <ayourtch@gmail.com>

1 files changed, 183 insertions, 0 deletions

diff --git a/vpp-api/lua/cough.c b/vpp-api/lua/cough.c
new file mode 100644
index 00000000000..4251c732202
--- /dev/null
+++ b/vpp-api/lua/cough.c
@@ -0,0 +1,183 @@
+/*
+ * 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);
+  }
+}