common.c

#include "common.h"

#include <arpa/inet.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

static int write_all(int fd, const void *buffer, size_t length) {
    const unsigned char *p = buffer;
    while (length > 0) {
        ssize_t n = send(fd, p, length, 0);
        if (n < 0 && errno == EINTR) continue;
        if (n <= 0) return -1;
        p += (size_t)n;
        length -= (size_t)n;
    }
    return 0;
}

static int read_all(int fd, void *buffer, size_t length) {
    unsigned char *p = buffer;
    while (length > 0) {
        ssize_t n = recv(fd, p, length, 0);
        if (n < 0 && errno == EINTR) continue;
        if (n <= 0) return -1;
        p += (size_t)n;
        length -= (size_t)n;
    }
    return 0;
}

int send_u32(int fd, uint32_t value) {
    value = htonl(value);
    return write_all(fd, &value, sizeof(value));
}

int recv_u32(int fd, uint32_t *value) {
    uint32_t wire;
    if (read_all(fd, &wire, sizeof(wire)) < 0) return -1;
    *value = ntohl(wire);
    return 0;
}

int send_blob(int fd, const void *data, uint32_t length) {
    if (send_u32(fd, length) < 0) return -1;
    return length == 0 ? 0 : write_all(fd, data, length);
}

int send_string(int fd, const char *text) {
    size_t length = strlen(text);
    if (length > UINT32_MAX) return -1;
    return send_blob(fd, text, (uint32_t)length);
}

int recv_blob(int fd, char **data, uint32_t *length, uint32_t maximum) {
    uint32_t n;
    char *result;
    if (recv_u32(fd, &n) < 0 || n > maximum) return -1;
    result = malloc((size_t)n + 1);
    if (!result) return -1;
    if (n > 0 && read_all(fd, result, n) < 0) {
        free(result);
        return -1;
    }
    result[n] = '\0';
    *data = result;
    if (length) *length = n;
    return 0;
}