io.c

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#ifndef _IO_C_ /* -*- linux-c -*- */
#define _IO_C_

#include "relay-app.h"
#include "print.c"

/** @file io.c
 * @brief I/O functions
 */
/** @addtogroup io I/O
 * I/O functions
 * @{
 */

/** private buffer for _stp_log() */
#define STP_LOG_BUF_LEN 2047
static char _stp_lbuf[NR_CPUS][STP_LOG_BUF_LEN + 1];

/** Logs Data.
 * This function prints to the system log if stpd has not connected
 * yet.  Otherwise it sends the message immediately to stpd.
 * @param fmt A variable number of args.
 * @note Lines are limited in length by printk buffer. If there is
 * no newline in the format string, then other syslog output could
 * get appended to the SystemTap line.
 * @todo Evaluate if this function is necessary.
 */

void _stp_log (const char *fmt, ...)
{
        int num;
        char *buf = &_stp_lbuf[smp_processor_id()][0];
        va_list args;
        va_start(args, fmt);
        num = vscnprintf (buf, STP_LOG_BUF_LEN, fmt, args);
        va_end(args);
        buf[num] = '\0';

        if (app.logging)
                send_reply (STP_REALTIME_DATA, buf, num + 1, stpd_pid);
        else
                printk("STP: %s", buf);
}

static void stpd_app_started(void)
{
        printk ("stpd has started.\n");
}

static void stpd_app_stopped(void)
{
        printk ("stpd has stopped.\n");
}

static void probe_exit(void);

#include <linux/delay.h>
static int stpd_command (int type, void *data)
{
        if (type == STP_EXIT) {
                printk ("STP_EXIT received\n");
                probe_exit();
#ifndef STP_NETLINK_ONLY
                relay_flush(app.chan);
                ssleep(2); /* FIXME: time for data to be flushed */
#endif
                send_reply (STP_EXIT, __this_module.name, strlen(__this_module.name) + 1, stpd_pid);
                return 1;
        }
        return 0;
}

/*
 * relay-app callbacks
 */
static struct relay_app_callbacks stp_callbacks =
{
        .app_started = stpd_app_started,
        .app_stopped = stpd_app_stopped,
        .user_command = stpd_command
};

/** Opens netlink and relayfs connections to stpd.
 * This must be called before any I/O is done, probably 
 * at the start of module initialization.
 */
int _stp_netlink_open(void)
{
        if (init_relay_app("stpd", "cpu", &stp_callbacks)) {
                printk ("STP: couldn't init relay app\n");
                return -1;
        }
        return 0;
}

/** Closes netlink and relayfs connections to stpd.
 * This must be called after all I/O is done, probably 
 * at the end of module cleanup.
 * @returns 0 on success.  -1 if there is a problem establishing
 * a connection.
 */
        
void _stp_netlink_close (void)
{
        send_reply (STP_DONE, NULL, 0, stpd_pid);
        close_relay_app();
}

/** @} */
#endif /* _IO_C_ */