/* -*- linux-c -*-
 *
 * relay_old.c - staprun relayfs functions for kernels with
 * old relayfs implementations.
 *
 * This file is part of systemtap, and is free software.  You can
 * redistribute it and/or modify it under the terms of the GNU General
 * Public License (GPL); either version 2, or (at your option) any
 * later version.
 *
 * Copyright (C) 2005-2007 Red Hat Inc.
 */

#include "staprun.h"

/* temporary per-cpu output written here for relayfs, filebase0...N */
static int relay_fd[NR_CPUS];
static int proc_fd[NR_CPUS];
static FILE *percpu_tmpfile[NR_CPUS];
static char *relay_buffer[NR_CPUS];
static pthread_t reader[NR_CPUS];
static int switch_file[NR_CPUS];
static int bulkmode = 0;
unsigned subbuf_size = 0;
unsigned n_subbufs = 0;

struct switchfile_ctrl_block {
	off_t wsize;
	int fnum;
	int rmfile;
};

static struct switchfile_ctrl_block global_scb = {0, 0, 0};

/* per-cpu buffer info */
static struct buf_status
{
	struct _stp_buf_info info;
	unsigned max_backlog; /* max # sub-buffers ready at one time */
} status[NR_CPUS];


/**
 *	close_relayfs_files - close and munmap buffer and open output file
 */
static void close_relayfs_files(int cpu)
{
	size_t total_bufsize = subbuf_size * n_subbufs;
	if (relay_fd[cpu] >= 0) {
		munmap(relay_buffer[cpu], total_bufsize);
		close(relay_fd[cpu]);
		close(proc_fd[cpu]);
		relay_fd[cpu] = -1;
		fclose(percpu_tmpfile[cpu]);
	}
}

/**
 *	close_all_relayfs_files - close and munmap buffers and output files
 */
void close_oldrelayfs(int detach)
{
	int i;

	if (!bulkmode)
		return;
	
	dbug(2, "detach=%d, ncpus=%d\n", detach, ncpus);
	
	if (detach) {
		for (i = 0; i < ncpus; i++)
			if (reader[i]) pthread_cancel(reader[i]);
	} else {
		for (i = 0; i < ncpus; i++)
			if (reader[i]) pthread_join(reader[i], NULL);
	}
	
	for (i = 0; i < ncpus; i++)
		close_relayfs_files(i);
}

static int open_oldoutfile(int fnum, int cpu, int remove_file)
{
	char buf[PATH_MAX];
	time_t t;
	if (outfile_name) {
		time(&t);
		if (fnum_max) {
			if (remove_file) {
				 /* remove oldest file */
				if (make_outfile_name(buf, PATH_MAX,
					fnum - fnum_max, cpu,
					read_backlog(cpu, fnum - fnum_max),
					bulkmode) < 0)
					return -1;
				remove(buf); /* don't care */
			}
			write_backlog(cpu, fnum, t);
		}
		if (make_outfile_name(buf, PATH_MAX, fnum, cpu, t, bulkmode) < 0)
			return -1;
	} else if (bulkmode) {
		if (sprintf_chk(buf, "stpd_cpu%d.%d", cpu, fnum))
			return -1;
	} else { /* stream mode */
		percpu_tmpfile[cpu] = stdout;
		return 0;
	}

	if((percpu_tmpfile[cpu] = fopen(buf, "w+")) == NULL) {
		perr("Couldn't open output file %s", buf);
		return -1;
	}
	out_fd[cpu] = fileno(percpu_tmpfile[cpu]);
	if (set_clexec(out_fd[cpu]) < 0) {
		perr("Couldn't clear exec bit of open output file %s", buf);
		return -1;
	}
	return 0;
}
/**
 *	open_relayfs_files - open and mmap buffer and open output file.
 *	Returns -1 on unexpected failure, 0 if file not found, 1 on success.
 */
static int open_relayfs_files(int cpu, const char *relay_filebase, const char *proc_filebase)
{
	size_t total_bufsize;
	char tmp[PATH_MAX];

	memset(&status[cpu], 0, sizeof(struct buf_status));
	status[cpu].info.cpu = cpu;

	if (sprintf_chk(tmp, "%s%d", relay_filebase, cpu))
		return -1;
	dbug(2, "Opening %s.\n", tmp); 
	relay_fd[cpu] = open_cloexec(tmp, O_RDONLY | O_NONBLOCK, 0);
	if (relay_fd[cpu] < 0) {
		relay_fd[cpu] = -1;
		return 0;
	}

	if (sprintf_chk(tmp, "%s%d", proc_filebase, cpu))
		goto err1;
	dbug(2, "Opening %s.\n", tmp); 
	proc_fd[cpu] = open_cloexec(tmp, O_RDWR | O_NONBLOCK, 0);
	if (proc_fd[cpu] < 0) {
		perr("Couldn't open proc file %s", tmp);
		goto err1;
	}

	if (fsize_max) {
		if (init_backlog(cpu) < 0)
			goto err2;
		if (open_oldoutfile(0, cpu, 0) < 0)
			goto err2;
		goto opened;
	}
	if (outfile_name) {
		/* special case: for testing we sometimes want to
		 * write to /dev/null */
		if (strcmp(outfile_name, "/dev/null") == 0) {
			/* This strcpy() is OK, since we know tmp is
			 * PATH_MAX bytes long. */
			strcpy(tmp, "/dev/null");
		} else {
			int len;
			len = stap_strfloctime(tmp, PATH_MAX, outfile_name, time(NULL));
			if (len < 0) {
				err("Invalid FILE name format\n");
				goto err2;
			}
			if (snprintf_chk(&tmp[len], PATH_MAX - len, "_%d", cpu))
				goto err2;
		}
	} else {
		if (sprintf_chk(tmp, "stpd_cpu%d", cpu))
			goto err2;
	}

	if((percpu_tmpfile[cpu] = fopen(tmp, "w+")) == NULL) {
		perr("Couldn't open output file %s", tmp);
		goto err2;
	}
	out_fd[cpu] = fileno(percpu_tmpfile[cpu]);
	if (set_clexec(out_fd[cpu]) < 0) {
		perr("Couldn't open output file %s", tmp);
		goto err2;
	}
opened:

	total_bufsize = subbuf_size * n_subbufs;
	relay_buffer[cpu] = mmap(NULL, total_bufsize, PROT_READ,
				 MAP_PRIVATE | MAP_POPULATE, relay_fd[cpu],
				 0);
	if(relay_buffer[cpu] == MAP_FAILED)
	{
		_perr("Couldn't mmap relay file, total_bufsize (%d)"	\
		     "= subbuf_size (%d) * n_subbufs(%d)",
		     (int)total_bufsize, (int)subbuf_size, (int)n_subbufs);
		goto err3;
	}
	
	return 1;
	
err3:
	fclose(percpu_tmpfile[cpu]);
err2:
	close (proc_fd[cpu]);
err1:
	close (relay_fd[cpu]);
	relay_fd[cpu] = -1;
	return -1;

}

static int switch_oldoutfile(int cpu, struct switchfile_ctrl_block *scb)
{
	dbug(3, "thread %d switching file\n", cpu);
	if (percpu_tmpfile[cpu])
		fclose(percpu_tmpfile[cpu]);
	else
		close(out_fd[cpu]);
	scb->fnum ++;
	if (fnum_max && scb->fnum == fnum_max)
		scb->rmfile = 1;
	if (open_oldoutfile(scb->fnum, cpu, scb->rmfile) < 0) {
		perr("Couldn't open file for cpu %d, exiting.", cpu);
		return -1;
	}
	return 0;
}
/**
 *	process_subbufs - write ready subbufs to disk
 */
static int process_subbufs(struct _stp_buf_info *info,
			   struct switchfile_ctrl_block *scb)
{
	unsigned subbufs_ready, start_subbuf, end_subbuf, subbuf_idx, i;
	int len, cpu = info->cpu;
	char *subbuf_ptr;
	int subbufs_consumed = 0;
	unsigned padding;

	subbufs_ready = info->produced - info->consumed;
	start_subbuf = info->consumed % n_subbufs;
	end_subbuf = start_subbuf + subbufs_ready;

	for (i = start_subbuf; i < end_subbuf; i++) {
		subbuf_idx = i % n_subbufs;
		subbuf_ptr = relay_buffer[cpu] + subbuf_idx * subbuf_size;
		padding = *((unsigned *)subbuf_ptr);
		subbuf_ptr += sizeof(padding);
		len = (subbuf_size - sizeof(padding)) - padding;
		scb->wsize += len;
		if (fsize_max && scb->wsize > fsize_max) {
			if (switch_oldoutfile(cpu, scb) < 0) {
				perr("Couldn't open file for cpu %d, exiting.", cpu);
				return -1;
			}
			scb->wsize = len;
		}
		if (len) {
			if (fwrite_unlocked (subbuf_ptr, len, 1, percpu_tmpfile[cpu]) != 1) {
				if (errno != EPIPE)
					_perr("Couldn't write to output file for cpu %d, exiting:", cpu);
				return -1;
			}
		}
		subbufs_consumed++;
	}

	return subbufs_consumed;
}

/**
 *	reader_thread - per-cpu channel buffer reader
 */
static void *reader_thread(void *data)
{
	int rc;
	int cpu = (long)data;
	struct pollfd pollfd;
	struct _stp_consumed_info consumed_info;
	unsigned subbufs_consumed;
	cpu_set_t cpu_mask;
	struct timespec tim = {.tv_sec=0, .tv_nsec=200000000}, *timeout = &tim;
	struct switchfile_ctrl_block scb = {0, 0, 0};
	sigset_t sigs;

	sigemptyset(&sigs);
	sigaddset(&sigs,SIGUSR2);
	pthread_sigmask(SIG_BLOCK, &sigs, NULL);

	sigfillset(&sigs);
	sigdelset(&sigs,SIGUSR2);
	
	CPU_ZERO(&cpu_mask);
	CPU_SET(cpu, &cpu_mask);
	if( sched_setaffinity( 0, sizeof(cpu_mask), &cpu_mask ) < 0 )
		_perr("sched_setaffinity");

	pollfd.fd = relay_fd[cpu];
	pollfd.events = POLLIN;
#ifdef NEED_PPOLL
	/* Without a real ppoll, there is a small race condition that could */
	/* block ppoll(). So use a timeout to prevent that. */
	timeout->tv_sec = 10;
	timeout->tv_nsec = 0;
#else
	timeout = NULL;
#endif

	do {
                rc = ppoll(&pollfd, 1, timeout, &sigs);
		if (rc < 0) {
			if (errno == EINTR) {
				if (switch_file[cpu]) {
					switch_file[cpu] = 0;
					if (switch_oldoutfile(cpu, &scb) < 0)
						break;
					scb.wsize = 0;
				}
			} else {
				_perr("poll error");
				break;
			}
			rc = 0;
		}

		rc = read(proc_fd[cpu], &status[cpu].info, sizeof(struct _stp_buf_info));
		rc = process_subbufs(&status[cpu].info, &scb);
		if (rc < 0)
			break;
		subbufs_consumed = rc;
		if (subbufs_consumed) {
			if (subbufs_consumed > status[cpu].max_backlog)
				status[cpu].max_backlog = subbufs_consumed;
			status[cpu].info.consumed += subbufs_consumed;
			consumed_info.cpu = cpu;
			consumed_info.consumed = subbufs_consumed;
			if (write (proc_fd[cpu], &consumed_info, sizeof(struct _stp_consumed_info)) < 0)
				perr("writing consumed info failed");
		}
		if (status[cpu].info.flushing)
			pthread_exit(NULL);
	} while (1);

	/* Signal the main thread that we need to quit */
	kill(getpid(), SIGTERM);
	pthread_exit(NULL);
}

/**
 *	write_realtime_data - write realtime data packet to disk
 */
int write_realtime_data(void *data, ssize_t nb)
{
	ssize_t bw;
	global_scb.wsize += nb;
	if (fsize_max && global_scb.wsize > fsize_max) {
		if (switch_oldoutfile(0, &global_scb) < 0) {
			perr("Couldn't open file, exiting.");
			return -1;
		}
		global_scb.wsize = nb;
	}
	bw = write(out_fd[0], data, nb);
	if (bw >= 0 && bw != nb) {
		nb = nb - bw;
		bw = write(out_fd[0], data, nb);
	}
	return bw != nb;
}

static void switchfile_handler(int sig)
{
	int i;
	for (i = 0; i < ncpus; i++)
		if (reader[i] && switch_file[i]) {
			dbug(2, "file switching is progressing, signal ignored.\n", sig);
			return;
		}
	for (i = 0; i < ncpus; i++) {
		if (reader[i]) {
			switch_file[i] = 1;
			pthread_kill(reader[i], SIGUSR2);
		} else
			break;
	}
}

/**
 *	init_relayfs - create files and threads for relayfs processing
 *
 *	Returns 0 if successful, negative otherwise
 */
int init_oldrelayfs(void)
{
	int i, j;
	struct statfs st;
	char relay_filebase[PATH_MAX], proc_filebase[PATH_MAX];
	struct sigaction sa;

	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = switchfile_handler;
	sa.sa_flags = 0;
	sigemptyset(&sa.sa_mask);
	sigaction(SIGUSR2, &sa, NULL);

	dbug(2, "initializing relayfs.n_subbufs=%d subbuf_size=%d\n", n_subbufs, subbuf_size);

	if (n_subbufs)
		bulkmode = 1;
 
	if (!bulkmode) {
		int len;
		char tmp[PATH_MAX];
		if (fsize_max) {
			if (init_backlog(0))
				return -1;
			return open_oldoutfile(0, 0, 0);
		}
		if (outfile_name) {
			len = stap_strfloctime(tmp, PATH_MAX, outfile_name, time(NULL));
			if (len < 0) {
				err("Invalid FILE name format\n");
				return -1;
			}
			out_fd[0] = open_cloexec (tmp, O_CREAT|O_TRUNC|O_WRONLY, 0666);
			if (out_fd[0] < 0) {
				perr("Couldn't open output file '%s'", tmp);
				return -1;
			}
		} else
			out_fd[0] = STDOUT_FILENO;
	  return 0;
	}

 	if (statfs("/sys/kernel/debug", &st) == 0
	    && (int) st.f_type == (int) DEBUGFS_MAGIC) {
		if (sprintf_chk(relay_filebase,
				"/sys/kernel/debug/systemtap/%s/trace",
				modname))
			return -1;
 		if (sprintf_chk(proc_filebase, 
				"/sys/kernel/debug/systemtap/%s/", modname))
			return -1;
	} else if (statfs("/mnt/relay", &st) == 0
		   && (int) st.f_type == (int) RELAYFS_MAGIC) {
		if (sprintf_chk(relay_filebase, "/mnt/relay/systemtap/%s/trace", modname))
			return -1;
		if (sprintf_chk(proc_filebase, "/proc/systemtap/%s/", modname))
			return -1;
 	} else {
		err("Cannot find relayfs or debugfs mount point.\n");
		return -1;
	}


	reader[0] = (pthread_t)0;
	relay_fd[0] = -1;
	out_fd[0] = 0;

	for (i = 0; i < NR_CPUS; i++) {
		int ret = open_relayfs_files(i, relay_filebase, proc_filebase);
		if (ret == 0)
			break;
		if (ret < 0) {
			err("Couldn't open relayfs files, cpu = %d\n", i);
			goto err;
		}
	}

	ncpus = i;
	dbug(2, "ncpus=%d\n", ncpus);

	if (ncpus == 0) {
		err("Couldn't open relayfs files.\n");
		return -1;
	}

	if (!load_only) {
		dbug(2, "starting threads\n");
		for (i = 0; i < ncpus; i++) {
			/* create a thread for each per-cpu buffer */
			if (pthread_create(&reader[i], NULL, reader_thread, (void *)(long)i) < 0) {
				int saved_errno = errno;
				close_relayfs_files(i);
				err("Couldn't create reader thread, cpu = %d: %s\n",
				    i, strerror(saved_errno));
				goto err;
			}
		}
	}
	return 0;
err:
	for (j = 0; j < i; j++)
		close_relayfs_files(j);

	for (j = 0; j < i; j++)
		if (reader[j]) pthread_cancel(reader[j]);
	
	return -1;
}