Import of the watch repository from Pebble

third_party/nanopb/examples/network_server/server.c

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+/* This is a simple TCP server that listens on port 1234 and provides lists
+ * of files to clients, using a protocol defined in file_server.proto.
+ *
+ * It directly deserializes and serializes messages from network, minimizing
+ * memory use.
+ * 
+ * For flexibility, this example is implemented using posix api.
+ * In a real embedded system you would typically use some other kind of
+ * a communication and filesystem layer.
+ */
+
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <pb_encode.h>
+#include <pb_decode.h>
+
+#include "fileproto.pb.h"
+#include "common.h"
+
+/* This callback function will be called during the encoding.
+ * It will write out any number of FileInfo entries, without consuming unnecessary memory.
+ * This is accomplished by fetching the filenames one at a time and encoding them
+ * immediately.
+ */
+bool ListFilesResponse_callback(pb_istream_t *istream, pb_ostream_t *ostream, const pb_field_iter_t *field)
+{
+    PB_UNUSED(istream);
+    if (ostream != NULL && field->tag == ListFilesResponse_file_tag)
+    {
+        DIR *dir = *(DIR**)field->pData;
+        struct dirent *file;
+        FileInfo fileinfo = {};
+
+        while ((file = readdir(dir)) != NULL)
+        {
+            fileinfo.inode = file->d_ino;
+            strncpy(fileinfo.name, file->d_name, sizeof(fileinfo.name));
+            fileinfo.name[sizeof(fileinfo.name) - 1] = '\0';
+
+            /* This encodes the header for the field, based on the constant info
+            * from pb_field_t. */
+            if (!pb_encode_tag_for_field(ostream, field))
+                return false;
+
+            /* This encodes the data for the field, based on our FileInfo structure. */
+            if (!pb_encode_submessage(ostream, FileInfo_fields, &fileinfo))
+                return false;
+        }
+
+        /* Because the main program uses pb_encode_delimited(), this callback will be
+        * called twice. Rewind the directory for the next call. */
+        rewinddir(dir);
+    }
+
+    return true;
+}
+
+/* Handle one arriving client connection.
+ * Clients are expected to send a ListFilesRequest, terminated by a '0'.
+ * Server will respond with a ListFilesResponse message.
+ */
+void handle_connection(int connfd)
+{
+    DIR *directory = NULL;
+    
+    /* Decode the message from the client and open the requested directory. */
+    {
+        ListFilesRequest request = {};
+        pb_istream_t input = pb_istream_from_socket(connfd);
+        
+        if (!pb_decode_delimited(&input, ListFilesRequest_fields, &request))
+        {
+            printf("Decode failed: %s\n", PB_GET_ERROR(&input));
+            return;
+        }
+        
+        directory = opendir(request.path);
+        printf("Listing directory: %s\n", request.path);
+    }
+    
+    /* List the files in the directory and transmit the response to client */
+    {
+        ListFilesResponse response = {};
+        pb_ostream_t output = pb_ostream_from_socket(connfd);
+        
+        if (directory == NULL)
+        {
+            perror("opendir");
+            
+            /* Directory was not found, transmit error status */
+            response.has_path_error = true;
+            response.path_error = true;
+        }
+        else
+        {
+            /* Directory was found, transmit filenames */
+            response.has_path_error = false;
+            response.file = directory;
+        }
+        
+        if (!pb_encode_delimited(&output, ListFilesResponse_fields, &response))
+        {
+            printf("Encoding failed: %s\n", PB_GET_ERROR(&output));
+        }
+    }
+    
+    if (directory != NULL)
+        closedir(directory);
+}
+
+int main(int argc, char **argv)
+{
+    int listenfd, connfd;
+    struct sockaddr_in servaddr;
+    int reuse = 1;
+    
+    /* Listen on localhost:1234 for TCP connections */
+    listenfd = socket(AF_INET, SOCK_STREAM, 0);
+    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
+    
+    memset(&servaddr, 0, sizeof(servaddr));
+    servaddr.sin_family = AF_INET;
+    servaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+    servaddr.sin_port = htons(1234);
+    if (bind(listenfd, (struct sockaddr*)&servaddr, sizeof(servaddr)) != 0)
+    {
+        perror("bind");
+        return 1;
+    }
+    
+    if (listen(listenfd, 5) != 0)
+    {
+        perror("listen");
+        return 1;
+    }
+    
+    for(;;)
+    {
+        /* Wait for a client */
+        connfd = accept(listenfd, NULL, NULL);
+        
+        if (connfd < 0)
+        {
+            perror("accept");
+            return 1;
+        }
+        
+        printf("Got connection.\n");
+        
+        handle_connection(connfd);
+        
+        printf("Closing connection.\n");
+        
+        close(connfd);
+    }
+    
+    return 0;
+}