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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.h"
bool write_callback(pb_ostream_t *stream, const uint8_t *buf, size_t count)
{
int fd = *(int*)stream->state;
return send(fd, buf, count, 0) == count;
}
bool read_callback(pb_istream_t *stream, uint8_t *buf, size_t count)
{
int fd = *(int*)stream->state;
if (buf == NULL)
{
/* Well, this is a really inefficient way to skip input. */
/* It is only used when there are unknown fields. */
char dummy;
while (count-- && recv(fd, &dummy, 1, 0) == 1);
return count == 0;
}
return recv(fd, buf, count, MSG_WAITALL) == count;
}
bool listdir_callback(pb_ostream_t *stream, const pb_field_t *field, const void *arg)
{
DIR *dir = (DIR*) arg;
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';
if (!pb_encode_tag_for_field(stream, field))
return false;
if (!pb_enc_submessage(stream, field, &fileinfo))
return false;
}
return true;
}
void handle_connection(int connfd)
{
ListFilesRequest request;
ListFilesResponse response;
pb_istream_t input = {&read_callback, &connfd, SIZE_MAX};
pb_ostream_t output = {&write_callback, &connfd, SIZE_MAX, 0};
DIR *directory;
if (!pb_decode(&input, ListFilesRequest_fields, &request))
{
printf("Decoding failed.\n");
return;
}
directory = opendir(request.path);
printf("Listing directory: %s\n", request.path);
if (directory == NULL)
{
perror("opendir");
response.has_path_error = true;
response.path_error = true;
response.file.funcs.encode = NULL;
}
else
{
response.has_path_error = false;
response.file.funcs.encode = &listdir_callback;
response.file.arg = directory;
}
if (!pb_encode(&output, ListFilesResponse_fields, &response))
{
printf("Encoding failed.\n");
}
}
int main(int argc, char **argv)
{
int listenfd, connfd;
struct sockaddr_in servaddr;
listenfd = socket(AF_INET, SOCK_STREAM, 0);
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(;;)
{
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);
}
}
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