Function handle_logs

src/ui/http_server.c:436–489

GET /api/logs?lines=N — returns last N log lines */

/* GET /api/logs?lines=N — returns last N log lines */
static void handle_logs(cbm_http_conn_t *c, const cbm_http_req_t *req) {
    char lines_str[16] = {0};
    int max_lines = 100;
    if (cbm_http_query_param(req->query, "lines", lines_str, (int)sizeof(lines_str))) {
        int v = atoi(lines_str);
        if (v > 0 && v <= LOG_RING_SIZE)
            max_lines = v;
    }

    cbm_mutex_lock(&g_log_mutex);
    int count = g_log_count < max_lines ? g_log_count : max_lines;
    int start = (g_log_head - count + LOG_RING_SIZE) % LOG_RING_SIZE;
    int total = g_log_count;

    /* Copy lines under lock */
    size_t buf_size = (size_t)count * (LOG_LINE_MAX + 10) + 64;
    char *buf = malloc(buf_size);
    if (!buf) {
        cbm_mutex_unlock(&g_log_mutex);
        cbm_http_replyf(c, 500, g_cors, "oom");
        return;
    }

    int pos = 0;
    http_appendf(buf, buf_size, &pos, "{\"lines\":[");
    for (int i = 0; i < count; i++) {
        int idx = (start + i) % LOG_RING_SIZE;
        if (i > 0)
            buf[pos++] = ',';
        /* Escape quotes in log lines */
        buf[pos++] = '"';
        for (int j = 0; g_log_ring[idx][j] && (size_t)pos < buf_size - 10; j++) {
            char ch = g_log_ring[idx][j];
            if (ch == '"') {
                buf[pos++] = '\\';
                buf[pos++] = '"';
            } else if (ch == '\\') {
                buf[pos++] = '\\';
                buf[pos++] = '\\';
            } else if (ch == '\n') {
                buf[pos++] = '\\';
                buf[pos++] = 'n';
            } else {
                buf[pos++] = ch;
            }
        }
        buf[pos++] = '"';
    }
    cbm_mutex_unlock(&g_log_mutex);
    http_appendf(buf, buf_size, &pos, "],\"total\":%d}", total);

    cbm_http_replyf(c, 200, g_cors_json, "%s", buf);
    free(buf);
}

/* ── Process monitoring ───────────────────────────────────────── */