FM / runtime

/usr/share/systemtap/runtime

Name	Size	Mode	Actions
dyninst/	-	0755	rm
linux/	-	0755	rm
softfloat/	-	0755	rm
transport/	-	0755	rm
unwind/	-	0755	rm
addr-map.c	523	0644	edit dl rm
addr-map.h	1156	0644	edit dl rm
alloc.c	498	0644	edit dl rm
arith.c	483	0644	edit dl rm
common_probe_context.h	6576	0644	edit dl rm
common_session_state.h	415	0644	edit dl rm
compatdefs.h	3682	0644	edit dl rm
copy.c	585	0644	edit dl rm
debug.h	485	0644	edit dl rm
io.c	508	0644	edit dl rm
k_syms.h	182	0644	edit dl rm
loc2c-runtime.h	17937	0644	edit dl rm
map-gen.c	25977	0644	edit dl rm
map-stat.c	3589	0644	edit dl rm
map.c	14660	0644	edit dl rm
map.h	5918	0644	edit dl rm
mempool.c	2644	0644	edit dl rm
namespaces.h	487	0644	edit dl rm
pmap-gen.c	8710	0644	edit dl rm
print.c	486	0644	edit dl rm
print.h	872	0644	edit dl rm
print_flush.c	3073	0644	edit dl rm
probe_lock.h	498	0644	edit dl rm
procfs-probes.c	4673	0644	edit dl rm
procfs-probes.h	674	0644	edit dl rm
procfs.c	4021	0644	edit dl rm
proc_fs_compatibility.h	2316	0644	edit dl rm
ptrace_compatibility.h	1512	0644	edit dl rm
regs.c	4280	0644	edit dl rm
regs.h	2352	0644	edit dl rm
runtime.h	928	0644	edit dl rm
runtime_context.h	669	0644	edit dl rm
runtime_defines.h	3582	0644	edit dl rm
softfloat.c	77159	0644	edit dl rm
softfloat.h	5125	0644	edit dl rm
stack-arm.c	1688	0644	edit dl rm
stack-ia64.c	1083	0644	edit dl rm
stack-mips.c	125	0644	edit dl rm
stack-s390.c	2362	0644	edit dl rm
stack.c	21790	0644	edit dl rm
stat-common.c	8486	0644	edit dl rm
stat.c	7421	0644	edit dl rm
stat.h	1964	0644	edit dl rm
stp_helper_lock.h	3669	0644	edit dl rm
stp_string.c	8632	0644	edit dl rm
stp_string.h	598	0644	edit dl rm
stp_task_work.c	3511	0644	edit dl rm
stp_utrace.c	94735	0644	edit dl rm
stp_utrace.h	14010	0644	edit dl rm
sym.c	39757	0644	edit dl rm
sym.h	6539	0644	edit dl rm
syscall.h	17408	0644	edit dl rm
task_finder_vma.c	13290	0644	edit dl rm
time.c	14887	0644	edit dl rm
timer.c	481	0644	edit dl rm
timer.h	482	0644	edit dl rm
uidgid_compatibility.h	603	0644	edit dl rm
unwind.c	47890	0644	edit dl rm
utrace_compatibility.h	3148	0644	edit dl rm
vma.c	9545	0644	edit dl rm
vsprintf.c	24058	0644	edit dl rm
vsprintf.h	1502	0644	edit dl rm

Edit: /usr/share/systemtap/runtime/procfs-probes.c (4673B)

/* -*- linux-c -*-
 *
 * /proc probe support functions
 * Copyright (C) 2010-2016 Red Hat Inc.
 *
 * 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.
 */

#ifndef _STP_PROCFS_PROBES_C_
#define _STP_PROCFS_PROBES_C_

#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/sched.h>

#include "procfs-probes.h"

struct stap_procfs_probe {
	const char *path;
	const struct stap_probe * const read_probe;
        struct stap_probe **write_probes;

int num_write_probes;
	char *buffer;
	const size_t bufsize;
	size_t count;
	int needs_fill;
	const int permissions;

struct mutex lock;
	int opencount;
	wait_queue_head_t waitq;
};

static inline void _spp_init(struct stap_procfs_probe *spp)
{
	init_waitqueue_head(&spp->waitq);
	spp->opencount = 0;
	mutex_init(&spp->lock);
}
#define _spp_lock(spp)		mutex_lock(&(spp)->lock)
#define _spp_unlock(spp)	mutex_unlock(&(spp)->lock)
#define _spp_shutdown(spp)	mutex_destroy(&(spp)->lock)

static int _stp_proc_fill_read_buffer(struct stap_procfs_probe *spp);

static int _stp_process_write_buffer(struct stap_procfs_probe *spp,
				     const char __user *buf, size_t count);

static int
_stp_proc_open_file(struct inode *inode, struct file *filp)
{
	struct stap_procfs_probe *spp;
	int res;

#ifdef STAPCONF_PDE_DATA2
	spp = (struct stap_procfs_probe *)pde_data(inode);
#else
	spp = (struct stap_procfs_probe *)PDE_DATA(inode);
#endif
	if (spp == NULL) {
		return -EINVAL;
	}

res = generic_file_open(inode, filp);
	if (res)
		return res;

/* To avoid concurrency problems, we only allow 1 open at a
	 * time. */

_spp_lock(spp);

/* If the file isn't open yet, ... */
	if (spp->opencount == 0) {
		res = 0;
	}
	/* If open() was called with O_NONBLOCK, don't block, just
	 * return EAGAIN. */
	else if (filp->f_flags & O_NONBLOCK) {
		res = -EAGAIN;
	}
	/* The file is already open, so wait. */
	else {
		for (res = 0;;) {
			if (spp->opencount == 0) {
				res = 0;
				break;
			}
			_spp_unlock(spp);
			res = wait_event_interruptible(spp->waitq,
						       spp->opencount == 0);
			_spp_lock(spp);
			if (res < 0)
				break;
		}
	}
	if (likely(res == 0)) {
		spp->opencount++;
		filp->private_data = spp;
		if ((filp->f_flags & O_ACCMODE) == O_RDONLY
		    && spp->read_probe != NULL) {
			spp->buffer[0] = '\0';
			spp->count = 0;
			spp->needs_fill = 1;
		}
	}

_spp_unlock(spp);
	return 0;
}

static int
_stp_proc_release_file(struct inode *inode, struct file *filp)
{
	struct stap_procfs_probe *spp;

spp = (struct stap_procfs_probe *)filp->private_data;
	if (spp != NULL) {
		/* Decrement the open count. */
		_spp_lock(spp);
		spp->opencount--;
		_spp_unlock(spp);

/* Wake up any tasks waiting to open the file. */
		wake_up(&spp->waitq);
	}
	return 0;
}

static ssize_t
_stp_proc_read_file(struct file *file, char __user *buf, size_t count,
		    loff_t *ppos) 
{
	struct stap_procfs_probe *spp = file->private_data;
	ssize_t retval = 0;

if (spp == NULL || spp->buffer == NULL) {
		goto out;
	}

/* If needed, fill up the buffer.*/
	if (spp->needs_fill) {
		if ((retval = _stp_proc_fill_read_buffer(spp))) {
			goto out;
		}
	}

/* Return bytes from the buffer. */
	retval = simple_read_from_buffer(buf, count, ppos, spp->buffer,
					 spp->count);
out:
	return retval;
}

static ssize_t
_stp_proc_write_file(struct file *file, const char __user *buf, size_t count,
		     loff_t *ppos) 
{
        int i;
        struct stap_procfs_probe *spp = file->private_data;
	struct _stp_procfs_data pdata;
	ssize_t len = -1;

/* If we don't have a write probe, return EIO. */
        if (spp->num_write_probes == 0) {
                len = -EIO;
                goto out;
	}

/* Handle the input buffer once for each write probe. */
        for (i = 0; i < spp->num_write_probes; i++, spp->write_probes++)
	        len = _stp_process_write_buffer(spp, buf, count);

spp->write_probes -= spp->num_write_probes;
	if (len > 0) {
		*ppos += len;
	}

out:
	return len;
}

#ifdef STAPCONF_PROC_OPS
static struct proc_ops _stp_proc_fops = {
	.proc_open		= _stp_proc_open_file,
	.proc_read		= _stp_proc_read_file,
	.proc_write		= _stp_proc_write_file,
	.proc_lseek		= generic_file_llseek,
	.proc_release	= _stp_proc_release_file,
};
#else
static struct file_operations _stp_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= _stp_proc_open_file,
	.read		= _stp_proc_read_file,
	.write		= _stp_proc_write_file,
	.llseek		= generic_file_llseek,
	.release	= _stp_proc_release_file,
};
#endif

#endif /* _STP_PROCFS_PROBES_C_ */

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