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#ifndef _TRANSPORT_RELAYFS_C_ /* -*- linux-c -*- */
#define _TRANSPORT_RELAYFS_C_
/*
* relayfs.c - stp relayfs-related transport functions
*
* Copyright (C) IBM Corporation, 2005
* Copyright (C) Redhat Inc, 2005
*
* This file is released under the GPL.
*/
/** @file relayfs.c
* @brief Systemtap relayfs-related transport functions
*/
/** @addtogroup transport Transport Functions
* @{
*/
#include "relayfs.h"
/**
* _stp_subbuf_start - subbuf_start() relayfs callback implementation
*/
static int _stp_subbuf_start(struct rchan_buf *buf,
void *subbuf,
unsigned prev_subbuf_idx,
void *prev_subbuf)
{
unsigned padding = buf->padding[prev_subbuf_idx];
if (prev_subbuf)
*((unsigned *)prev_subbuf) = padding;
return sizeof(padding); /* reserve space for padding */
}
/**
* _stp_buf_full - buf_full() relayfs callback implementation
*/
static void _stp_buf_full(struct rchan_buf *buf,
unsigned subbuf_idx,
void *subbuf)
{
unsigned padding = buf->padding[subbuf_idx];
*((unsigned *)subbuf) = padding;
}
/* relayfs callback functions */
static struct rchan_callbacks stp_rchan_callbacks =
{
.subbuf_start = _stp_subbuf_start,
.buf_full = _stp_buf_full,
};
/**
* _stp_relayfs_close - destroys relayfs channel
* @chan: the relayfs channel
* @dir: the directory containing the relayfs files
*/
void _stp_relayfs_close(struct rchan *chan, struct dentry *dir)
{
if (!chan)
return;
relay_close(chan);
if (dir)
relayfs_remove_dir(dir);
}
/**
* _stp_relayfs_open - create relayfs channel
* @n_subbufs: number of relayfs sub-buffers
* @subbuf_size: size of relayfs sub-buffers
* @pid: daemon pid
* @outdir: receives directory dentry
*
* Returns relay channel, NULL on failure
*
* Creates relayfs files as /systemtap/pid/cpuX in relayfs root
*/
struct rchan *_stp_relayfs_open(unsigned n_subbufs,
unsigned subbuf_size,
int pid,
struct dentry **outdir)
{
char dirname[16];
struct rchan *chan;
struct dentry* dir = NULL;
sprintf(dirname, "%d", pid);
/* TODO: need to create systemtap dir */
dir = relayfs_create_dir(dirname, NULL);
if (!dir) {
printk("STP: couldn't create relayfs dir %s.\n", dirname);
return NULL;
}
chan = relay_open("cpu", dir, subbuf_size,
n_subbufs, 0, &stp_rchan_callbacks);
if (!chan) {
printk("STP: couldn't create relayfs channel.\n");
if (dir)
relayfs_remove_dir(dir);
}
*outdir = dir;
return chan;
}
#endif /* _TRANSPORT_RELAYFS_C_ */
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