path: root/03_exercise/cli/client.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define PORT 9000
#define HOST "127.0.0.1"

#define BUF_SIZE 2048

int cfd;

/* Signal Handler for SIGINT */
void sigintHandler(int sig_num) {
    errno = 0;
    if (fcntl(cfd, F_GETFD) != -1 || errno != EBADF) {
        write(cfd, "exit\n", 6);
        close(cfd);
    }
    printf("Terminating client\n");
    fflush(stdout);
    exit(-1);
}

static inline void die(const char *msg) {
    perror(msg);
    exit(-1);
}

int write_all(int sock, char *buffer, int size) {
    int nwrite, sent = 0;

    while (sent < size) {
        if ((nwrite = write(sock, buffer + sent, size - sent)) < 0) {
            perror("Write");
            exit(1);
        }

        sent += nwrite;
    }

    return sent;
}

void send_file(int server_fd, char *path) {
    char buffer[512];
    int  file_fd;

    if ((file_fd = open(path, O_RDONLY)) == -1) { perror("Open"); }

    FILE *file = fdopen(file_fd, "r");

    fseek(file, 0L, SEEK_END);
    long int sz = ftell(file);
    fseek(file, 0L, SEEK_SET);

    int  length = snprintf(NULL, 0, "%ld", sz);
    char msg[length + 1 + 3];
    sprintf(msg, "<<!%ld", sz);

    write(server_fd, msg, strlen(msg));

    int size;
    while (read(file_fd, buffer, sizeof(buffer)) != 0) {
        size = strlen(buffer) + 1;
        if (write(server_fd, &size, sizeof(size)) < 0) {
            perror("Write");
            exit(1);
        }

        printf("Sent %i bytes\n", write_all(server_fd, buffer, strlen(buffer) + 1));
    }

    fclose(file);
    close(file_fd);
}

int main() {
    struct sockaddr_in addr = {
            .sin_family = AF_INET,
            .sin_port = htons(PORT),
            .sin_addr.s_addr = inet_addr(HOST)
    };
    char               buf[BUF_SIZE];

    if ((cfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        die("Could not open socket");

    if (connect(cfd, (struct sockaddr *) &addr, sizeof(addr)) < 0)
        die("Could not connect to socket");

    char      *line = NULL;
    size_t    cap   = 0;
    __ssize_t length;

    if (read(cfd, buf, BUF_SIZE) < 0)
        die("Could not receive message");

    printf("%s\n", buf);
    memset(buf, 0, BUF_SIZE);

    while (1) {
        printf("$> ");
        //printf("[C] awaiting command\n");
        if ((length = getline(&line, &cap, stdin)) < 0) {
            fprintf(stderr, "Failed to read from STDIN");
            fflush(stderr);
            exit(-1);
        }

        if (strspn(line, " \n\t") == strlen(line)) {
            // skip empty lines - empty being just spaces or tabs
            continue;
        }

        char cmd[4];
        char path[BUF_SIZE - 3];
        memcpy(cmd, line, 3);
        cmd[3] = 0;
        memcpy(path, line + 4, BUF_SIZE - 4);
        path[strlen(path) - 1] = 0;
        printf("cmd: \"%s\"\n", cmd);
        printf("path: \"%s\"\n", path);
        if (strcmp(cmd, "put") == 0) {
            if (strlen(path) == 0) {
                fprintf(stderr, "path missing\n");
            } else {
                printf("got put with %s\n", path);
                send_file(cfd, path);
            }
            free(line);
            line = NULL;
            continue;
        }

        strncpy(buf, line, strlen(line) + 1);

        //printf("[C] pre send: \"%s\"\n", buf);

        if (write(cfd, buf, strlen(line)) < 0)
            die("Could not send message");

        if (strcmp(line, "exit\n") == 0) {
            free(line);
            line = NULL;
            break;
        }

        if (read(cfd, buf, BUF_SIZE) < 0)
            die("Could not receive message");

        printf("%s", buf);
        memset(buf, 0, BUF_SIZE);
        free(line);
        line = NULL;
    }

    close(cfd);
    return 0;
}