| /* This is a simple TCP client that connects to port 1234 and prints a list |
| * of files in a given directory. |
| * |
| * 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 once for each filename received |
| * from the server. The filenames will be printed out immediately, so that |
| * no memory has to be allocated for them. |
| */ |
| bool ListFilesResponse_callback(pb_istream_t *istream, pb_ostream_t *ostream, const pb_field_iter_t *field) |
| { |
| PB_UNUSED(ostream); |
| if (istream != NULL && field->tag == ListFilesResponse_file_tag) |
| { |
| FileInfo fileinfo = {}; |
| |
| if (!pb_decode(istream, FileInfo_fields, &fileinfo)) |
| return false; |
| |
| printf("%-10lld %s\n", (long long)fileinfo.inode, fileinfo.name); |
| } |
| |
| return true; |
| } |
| |
| /* This function sends a request to socket 'fd' to list the files in |
| * directory given in 'path'. The results received from server will |
| * be printed to stdout. |
| */ |
| bool listdir(int fd, char *path) |
| { |
| /* Construct and send the request to server */ |
| { |
| ListFilesRequest request = {}; |
| pb_ostream_t output = pb_ostream_from_socket(fd); |
| |
| /* In our protocol, path is optional. If it is not given, |
| * the server will list the root directory. */ |
| if (path == NULL) |
| { |
| request.has_path = false; |
| } |
| else |
| { |
| request.has_path = true; |
| if (strlen(path) + 1 > sizeof(request.path)) |
| { |
| fprintf(stderr, "Too long path.\n"); |
| return false; |
| } |
| |
| strcpy(request.path, path); |
| } |
| |
| /* Encode the request. It is written to the socket immediately |
| * through our custom stream. */ |
| if (!pb_encode_delimited(&output, ListFilesRequest_fields, &request)) |
| { |
| fprintf(stderr, "Encoding failed: %s\n", PB_GET_ERROR(&output)); |
| return false; |
| } |
| } |
| |
| /* Read back the response from server */ |
| { |
| ListFilesResponse response = {}; |
| pb_istream_t input = pb_istream_from_socket(fd); |
| |
| if (!pb_decode_delimited(&input, ListFilesResponse_fields, &response)) |
| { |
| fprintf(stderr, "Decode failed: %s\n", PB_GET_ERROR(&input)); |
| return false; |
| } |
| |
| /* If the message from server decodes properly, but directory was |
| * not found on server side, we get path_error == true. */ |
| if (response.path_error) |
| { |
| fprintf(stderr, "Server reported error.\n"); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| int main(int argc, char **argv) |
| { |
| int sockfd; |
| struct sockaddr_in servaddr; |
| char *path = NULL; |
| |
| if (argc > 1) |
| path = argv[1]; |
| |
| sockfd = socket(AF_INET, SOCK_STREAM, 0); |
| |
| /* Connect to server running on localhost:1234 */ |
| memset(&servaddr, 0, sizeof(servaddr)); |
| servaddr.sin_family = AF_INET; |
| servaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK); |
| servaddr.sin_port = htons(1234); |
| |
| if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0) |
| { |
| perror("connect"); |
| return 1; |
| } |
| |
| /* Send the directory listing request */ |
| if (!listdir(sockfd, path)) |
| return 2; |
| |
| /* Close connection */ |
| close(sockfd); |
| |
| return 0; |
| } |