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139 lines
3.8 KiB
139 lines
3.8 KiB
/* This is a simple TCP client that connects to port 1234 and prints a list
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* of files in a given directory.
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*
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* It directly deserializes and serializes messages from network, minimizing
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* memory use.
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*
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* For flexibility, this example is implemented using posix api.
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* In a real embedded system you would typically use some other kind of
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* a communication and filesystem layer.
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*/
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <unistd.h>
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#include <dirent.h>
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#include <stdio.h>
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#include <string.h>
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#include <pb_encode.h>
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#include <pb_decode.h>
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#include "fileproto.pb.h"
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#include "common.h"
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/* This callback function will be called once for each filename received
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* from the server. The filenames will be printed out immediately, so that
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* no memory has to be allocated for them.
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*/
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bool printfile_callback(pb_istream_t *stream, const pb_field_t *field, void **arg)
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{
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FileInfo fileinfo = {};
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if (!pb_decode(stream, FileInfo_fields, &fileinfo))
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return false;
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printf("%-10lld %s\n", (long long)fileinfo.inode, fileinfo.name);
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return true;
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}
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/* This function sends a request to socket 'fd' to list the files in
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* directory given in 'path'. The results received from server will
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* be printed to stdout.
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*/
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bool listdir(int fd, char *path)
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{
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/* Construct and send the request to server */
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{
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ListFilesRequest request = {};
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pb_ostream_t output = pb_ostream_from_socket(fd);
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/* In our protocol, path is optional. If it is not given,
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* the server will list the root directory. */
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if (path == NULL)
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{
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request.has_path = false;
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}
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else
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{
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request.has_path = true;
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if (strlen(path) + 1 > sizeof(request.path))
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{
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fprintf(stderr, "Too long path.\n");
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return false;
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}
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strcpy(request.path, path);
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}
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/* Encode the request. It is written to the socket immediately
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* through our custom stream. */
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if (!pb_encode_delimited(&output, ListFilesRequest_fields, &request))
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{
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fprintf(stderr, "Encoding failed: %s\n", PB_GET_ERROR(&output));
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return false;
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}
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}
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/* Read back the response from server */
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{
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ListFilesResponse response = {};
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pb_istream_t input = pb_istream_from_socket(fd);
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/* Give a pointer to our callback function, which will handle the
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* filenames as they arrive. */
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response.file.funcs.decode = &printfile_callback;
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if (!pb_decode_delimited(&input, ListFilesResponse_fields, &response))
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{
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fprintf(stderr, "Decode failed: %s\n", PB_GET_ERROR(&input));
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return false;
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}
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/* If the message from server decodes properly, but directory was
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* not found on server side, we get path_error == true. */
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if (response.path_error)
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{
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fprintf(stderr, "Server reported error.\n");
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return false;
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}
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}
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return true;
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}
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int main(int argc, char **argv)
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{
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int sockfd;
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struct sockaddr_in servaddr;
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char *path = NULL;
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if (argc > 1)
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path = argv[1];
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sockfd = socket(AF_INET, SOCK_STREAM, 0);
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/* Connect to server running on localhost:1234 */
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memset(&servaddr, 0, sizeof(servaddr));
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servaddr.sin_family = AF_INET;
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servaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
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servaddr.sin_port = htons(1234);
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if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0)
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{
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perror("connect");
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return 1;
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}
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/* Send the directory listing request */
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if (!listdir(sockfd, path))
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return 2;
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/* Close connection */
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close(sockfd);
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return 0;
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}
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