1 /* This is a simple TCP client that connects to port 1234 and prints a list
2 * of files in a given directory.
3 *
4 * It directly deserializes and serializes messages from network, minimizing
5 * memory use.
6 *
7 * For flexibility, this example is implemented using posix api.
8 * In a real embedded system you would typically use some other kind of
9 * a communication and filesystem layer.
10 */
11
12 #include <sys/socket.h>
13 #include <sys/types.h>
14 #include <netinet/in.h>
15 #include <unistd.h>
16 #include <dirent.h>
17 #include <stdio.h>
18 #include <string.h>
19
20 #include <pb_encode.h>
21 #include <pb_decode.h>
22
23 #include "fileproto.pb.h"
24 #include "common.h"
25
26 /* This callback function will be called once for each filename received
27 * from the server. The filenames will be printed out immediately, so that
28 * no memory has to be allocated for them.
29 */
ListFilesResponse_callback(pb_istream_t * istream,pb_ostream_t * ostream,const pb_field_iter_t * field)30 bool ListFilesResponse_callback(pb_istream_t *istream, pb_ostream_t *ostream, const pb_field_iter_t *field)
31 {
32 PB_UNUSED(ostream);
33 if (istream != NULL && field->tag == ListFilesResponse_file_tag)
34 {
35 FileInfo fileinfo = {};
36
37 if (!pb_decode(istream, FileInfo_fields, &fileinfo))
38 return false;
39
40 printf("%-10lld %s\n", (long long)fileinfo.inode, fileinfo.name);
41 }
42
43 return true;
44 }
45
46 /* This function sends a request to socket 'fd' to list the files in
47 * directory given in 'path'. The results received from server will
48 * be printed to stdout.
49 */
listdir(int fd,char * path)50 bool listdir(int fd, char *path)
51 {
52 /* Construct and send the request to server */
53 {
54 ListFilesRequest request = {};
55 pb_ostream_t output = pb_ostream_from_socket(fd);
56
57 /* In our protocol, path is optional. If it is not given,
58 * the server will list the root directory. */
59 if (path == NULL)
60 {
61 request.has_path = false;
62 }
63 else
64 {
65 request.has_path = true;
66 if (strlen(path) + 1 > sizeof(request.path))
67 {
68 fprintf(stderr, "Too long path.\n");
69 return false;
70 }
71
72 strcpy(request.path, path);
73 }
74
75 /* Encode the request. It is written to the socket immediately
76 * through our custom stream. */
77 if (!pb_encode_delimited(&output, ListFilesRequest_fields, &request))
78 {
79 fprintf(stderr, "Encoding failed: %s\n", PB_GET_ERROR(&output));
80 return false;
81 }
82 }
83
84 /* Read back the response from server */
85 {
86 ListFilesResponse response = {};
87 pb_istream_t input = pb_istream_from_socket(fd);
88
89 if (!pb_decode_delimited(&input, ListFilesResponse_fields, &response))
90 {
91 fprintf(stderr, "Decode failed: %s\n", PB_GET_ERROR(&input));
92 return false;
93 }
94
95 /* If the message from server decodes properly, but directory was
96 * not found on server side, we get path_error == true. */
97 if (response.path_error)
98 {
99 fprintf(stderr, "Server reported error.\n");
100 return false;
101 }
102 }
103
104 return true;
105 }
106
main(int argc,char ** argv)107 int main(int argc, char **argv)
108 {
109 int sockfd;
110 struct sockaddr_in servaddr;
111 char *path = NULL;
112
113 if (argc > 1)
114 path = argv[1];
115
116 sockfd = socket(AF_INET, SOCK_STREAM, 0);
117
118 /* Connect to server running on localhost:1234 */
119 memset(&servaddr, 0, sizeof(servaddr));
120 servaddr.sin_family = AF_INET;
121 servaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
122 servaddr.sin_port = htons(1234);
123
124 if (connect(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) != 0)
125 {
126 perror("connect");
127 return 1;
128 }
129
130 /* Send the directory listing request */
131 if (!listdir(sockfd, path))
132 return 2;
133
134 /* Close connection */
135 close(sockfd);
136
137 return 0;
138 }
139
