Added error checking and other updates.

* runtime/vsprintf.c: Added transport.h inclusion for STP_BUFFER_SIZE
  definition.

* runtime/transport/debugfs.c (_stp_register_ctl_channel_fs): Added error
  checking.
* runtime/transport/transport.c (_stp_get_root_dir): Ditto.
  (_stp_transport_fs_init): Added original transport support and error
  checking.
* runtime/transport/relay_v2.c (__stp_relay_create_buf_file_callback):
  Added error checking.
  (_stp_transport_data_fs_init): Ditto.
* runtime/transport/ring_buffer.c (_stp_transport_data_fs_init): Ditto.

* runtime/transport/utt.c: Removed unused file.
* runtime/transport/utt.h: Ditto.

6 files changed, 42 insertions, 488 deletions

diff --git a/runtime/transport/debugfs.c b/runtime/transport/debugfs.c
index 7a08982a..6bbef53b 100644
--- a/runtime/transport/debugfs.c
+++ b/runtime/transport/debugfs.c
@@ -36,6 +36,13 @@ static int _stp_register_ctl_channel_fs(void)
 		errk("Error creating systemtap debugfs entries.\n");
 		return -1;
 	}
+	else if (IS_ERR(_stp_cmd_file)) {
+		_stp_cmd_file = NULL;
+		errk("Error creating systemtap debugfs entries: %ld\n",
+		     -PTR_ERR(_stp_cmd_file));
+		return -1;
+	}
+
 	_stp_cmd_file->d_inode->i_uid = _stp_uid;
 	_stp_cmd_file->d_inode->i_gid = _stp_gid;
 
diff --git a/runtime/transport/relay_v2.c b/runtime/transport/relay_v2.c
index c0a772ed..0c8d0955 100644
--- a/runtime/transport/relay_v2.c
+++ b/runtime/transport/relay_v2.c
@@ -204,7 +204,10 @@ __stp_relay_create_buf_file_callback(const char *filename,
 {
 	struct dentry *file = debugfs_create_file(filename, mode, parent, buf,
 						  &relay_file_operations);
-	if (file) {
+	if (IS_ERR(file)) {
+		file = NULL;
+	}
+	else if (file) {
 		file->d_inode->i_uid = _stp_uid;
 		file->d_inode->i_gid = _stp_gid;
 	}
@@ -251,6 +254,12 @@ static int _stp_transport_data_fs_init(void)
 		rc = -EIO;
 		goto err;
 	}
+	else if (IS_ERR(_stp_relay_data.dropped_file)) {
+		rc = PTR_ERR(_stp_relay_data.dropped_file);
+		_stp_relay_data.dropped_file = NULL;
+		goto err;
+	}
+
 	_stp_relay_data.dropped_file->d_inode->i_uid = _stp_uid;
 	_stp_relay_data.dropped_file->d_inode->i_gid = _stp_gid;
 
diff --git a/runtime/transport/ring_buffer.c b/runtime/transport/ring_buffer.c
index 0385e7d3..217d0735 100644
--- a/runtime/transport/ring_buffer.c
+++ b/runtime/transport/ring_buffer.c
@@ -405,6 +405,13 @@ static int _stp_transport_data_fs_init(void)
 			__stp_free_ring_buffer();
 			return -ENOENT;
 		}
+		else if (IS_ERR(__stp_entry[cpu])) {
+			rc = PTR_ERR(__stp_entry[cpu]);
+			pr_warning("Could not create debugfs 'trace' entry\n");
+			__stp_free_ring_buffer();
+			return rc;
+		}
+
 		__stp_entry[cpu]->d_inode->i_uid = _stp_uid;
 		__stp_entry[cpu]->d_inode->i_gid = _stp_gid;
 
diff --git a/runtime/transport/transport.c b/runtime/transport/transport.c
index 792ea815..ab0806f2 100644
--- a/runtime/transport/transport.c
+++ b/runtime/transport/transport.c
@@ -453,6 +453,12 @@ static struct dentry *_stp_get_root_dir(void)
 			errk("Could not create or find transport directory.\n");
 		}
 	}
+	else if (IS_ERR(__stp_root_dir)) {
+	    __stp_root_dir = NULL;
+	    errk("Could not create root directory \"%s\", error %ld\n", name,
+		 -PTR_ERR(__stp_root_dir));
+	}
+
 	_stp_unlock_transport_dir();
 	return __stp_root_dir;
 }
@@ -490,8 +496,20 @@ static int _stp_transport_fs_init(const char *module_name)
 	if (root_dir == NULL)
 		return -1;
 
+#if STP_TRANSPORT_VERSION == 1
+        __stp_module_dir = relayfs_create_dir(module_name, root_dir);
+#else
         __stp_module_dir = debugfs_create_dir(module_name, root_dir);
+#endif
         if (!__stp_module_dir) {
+		errk("Could not create module directory \"%s\"\n",
+		     module_name);
+		_stp_remove_root_dir();
+		return -1;
+	}
+	else if (IS_ERR(__stp_module_dir)) {
+		errk("Could not create module directory \"%s\", error %ld\n",
+		     module_name, -PTR_ERR(__stp_module_dir));
 		_stp_remove_root_dir();
 		return -1;
 	}
diff --git a/runtime/transport/utt.c b/runtime/transport/utt.c
deleted file mode 100644
index 2dd303a5..00000000
--- a/runtime/transport/utt.c
+++ /dev/null
@@ -1,404 +0,0 @@
-/* -*- linux-c -*- 
- *
- * This is a modified version of the proposed utt interface. If that
- * interface makes it into the kernel, this file can go away.
- *
- * Copyright (C) 2006 Jens Axboe <axboe@suse.de>
- *
- * Moved to utt.c by Tom Zanussi, 2006
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- */
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/percpu.h>
-#include <linux/init.h>
-#include <linux/debugfs.h>
-#include <linux/mm.h>
-#include "utt.h"
-
-static int utt_overwrite_flag = 0;
-
-/*
- *	utt_switch_subbuf - switch to a new sub-buffer
- *
- *	Most of this function is deadcopy of relay_switch_subbuf.
- */
-static size_t utt_switch_subbuf(struct utt_trace *utt, struct rchan_buf *buf,
-			 size_t length)
-{
-	char *old, *new;
-	size_t old_subbuf, new_subbuf;
-
-	if (unlikely(buf == NULL))
-		return 0;
-
-	if (unlikely(length > buf->chan->subbuf_size))
-		goto toobig;
-
-	if (buf->offset != buf->chan->subbuf_size + 1) {
-		buf->prev_padding = buf->chan->subbuf_size - buf->offset;
-		old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
-		buf->padding[old_subbuf] = buf->prev_padding;
-		buf->subbufs_produced++;
-		buf->dentry->d_inode->i_size += buf->chan->subbuf_size -
-			buf->padding[old_subbuf];
-		smp_mb();
-		if (waitqueue_active(&buf->read_wait))
-			/*
-			 * Calling wake_up_interruptible() and __mod_timer()
-			 * from here will deadlock if we happen to be logging
-			 * from the scheduler and timer (trying to re-grab
-			 * rq->lock/timer->base->lock), so just set a flag.
-			 */
-			atomic_set(&utt->wakeup, 1);
-	}
-
-	old = buf->data;
-	new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
-	new = (char*)buf->start + new_subbuf * buf->chan->subbuf_size;
-	buf->offset = 0;
-	if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) {
-		buf->offset = buf->chan->subbuf_size + 1;
-		return 0;
-	}
-	buf->data = new;
-	buf->padding[new_subbuf] = 0;
-
-	if (unlikely(length + buf->offset > buf->chan->subbuf_size))
-		goto toobig;
-
-	return length;
-
-toobig:
-	buf->chan->last_toobig = length;
-	return 0;
-}
-
-static void __utt_wakeup_readers(struct rchan_buf *buf)
-{
-	if (buf && waitqueue_active(&buf->read_wait) &&
-	    buf->subbufs_produced != buf->subbufs_consumed)
-		wake_up_interruptible(&buf->read_wait);
-}
-
-static void __utt_wakeup_timer(unsigned long val)
-{
-	struct utt_trace *utt = (struct utt_trace *)val;
-	int i;
-
-	if (atomic_read(&utt->wakeup)) {
-		atomic_set(&utt->wakeup, 0);
-		if (utt->is_global)
-			__utt_wakeup_readers(utt->rchan->buf[0]);
-		else
-			for_each_possible_cpu(i)
-				__utt_wakeup_readers(utt->rchan->buf[i]);
-	}
-
- 	mod_timer(&utt->timer, jiffies + UTT_TIMER_INTERVAL);
-}
-
-static void __utt_timer_init(struct utt_trace * utt)
-{
-	atomic_set(&utt->wakeup, 0);
-	init_timer(&utt->timer);
-	utt->timer.expires = jiffies + UTT_TIMER_INTERVAL;
-	utt->timer.function = __utt_wakeup_timer;
-	utt->timer.data = (unsigned long)utt;
-	add_timer(&utt->timer);
-}
-
-static void utt_set_overwrite(int overwrite)
-{
-	utt_overwrite_flag = overwrite;
-}
-
-static void utt_remove_root(struct utt_trace *utt)
-{
-	if (utt->utt_tree_root) {
-		if (!_stp_lock_transport_dir()) {
-			errk("Unable to lock transport directory.\n");
-			return;
-		}
-		if (simple_empty(utt->utt_tree_root))
-			debugfs_remove(utt->utt_tree_root);
-		_stp_unlock_transport_dir();
-		utt->utt_tree_root = NULL;
-	}
-}
-
-static void utt_remove_tree(struct utt_trace *utt)
-{
-	if (utt == NULL || utt->dir == NULL)
-		return;
-	debugfs_remove(utt->dir);
-	utt_remove_root(utt);
-}
-
-static struct dentry *utt_create_tree(struct utt_trace *utt, const char *root, const char *name)
-{
-        struct dentry *dir = NULL;
-
-        if (root == NULL || name == NULL)
-                return NULL;
-
-        if (!utt->utt_tree_root) {
-                utt->utt_tree_root = _stp_get_root_dir();
-                if (!utt->utt_tree_root)
-                        goto err;
-        }
-
-        dir = debugfs_create_dir(name, utt->utt_tree_root);
-        if (!dir)
-                utt_remove_root(utt);
-err:
-        return dir;
-}
-
-static void utt_trace_cleanup(struct utt_trace *utt)
-{
-	if (utt == NULL)
-		return;
-	if (utt->rchan)
-		relay_close(utt->rchan);
-	if (utt->dropped_file)
-		debugfs_remove(utt->dropped_file);
-	utt_remove_tree(utt);
-	_stp_kfree(utt);
-}
-
-static int utt_trace_remove(struct utt_trace *utt)
-{
-	if (utt->trace_state == Utt_trace_setup ||
-	    utt->trace_state == Utt_trace_stopped)
-		utt_trace_cleanup(utt);
-
-	return 0;
-}
-
-static int utt_dropped_open(struct inode *inode, struct file *filp)
-{
-#ifdef STAPCONF_INODE_PRIVATE
-	filp->private_data = inode->i_private;
-#else
-	filp->private_data = inode->u.generic_ip;
-#endif
-	return 0;
-}
-
-static ssize_t utt_dropped_read(struct file *filp, char __user *buffer,
-				size_t count, loff_t *ppos)
-{
-	struct utt_trace *utt = filp->private_data;
-	char buf[16];
-
-	snprintf(buf, sizeof(buf), "%u\n", atomic_read(&utt->dropped));
-
-	return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
-}
-
-static struct file_operations utt_dropped_fops = {
-	.owner =	THIS_MODULE,
-	.open =		utt_dropped_open,
-	.read =		utt_dropped_read,
-};
-
-/*
- * Keep track of how many times we encountered a full subbuffer, to aid
- * the user space app in telling how many lost events there were.
- */
-static int utt_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
-				     void *prev_subbuf, size_t prev_padding)
-{
-	struct utt_trace *utt;
-
-	if (utt_overwrite_flag || !relay_buf_full(buf))
-		return 1;
-
-	utt = buf->chan->private_data;
-	atomic_inc(&utt->dropped);
-	return 0;
-}
-
-static int utt_remove_buf_file_callback(struct dentry *dentry)
-{
-	debugfs_remove(dentry);
-	return 0;
-}
-
-static struct dentry *utt_create_buf_file_callback(const char *filename,
-						   struct dentry *parent,
-						   int mode,
-						   struct rchan_buf *buf,
-						   int *is_global)
-{
-	struct dentry *file = debugfs_create_file(filename, mode, parent, buf,
-				   &relay_file_operations);
-	if (file) {
-		file->d_inode->i_uid = _stp_uid;
-		file->d_inode->i_gid = _stp_gid;
-	}
-	return  file;
-}
-
-static struct dentry *utt_create_global_buf_file_callback(const char *filename,
-							  struct dentry *parent,
-							  int mode,
-							  struct rchan_buf *buf,
-							  int *is_global)
-{
-	struct dentry *file; 
-	*is_global = 1;
-	file = debugfs_create_file(filename, mode, parent, buf,
-				   &relay_file_operations);
-	if (file) {
-		file->d_inode->i_uid = _stp_uid;
-		file->d_inode->i_gid = _stp_gid;
-	}
-	return  file;
-}
-
-static struct rchan_callbacks utt_relay_callbacks = {
-	.subbuf_start		= utt_subbuf_start_callback,
-	.create_buf_file	= utt_create_buf_file_callback,
-	.remove_buf_file	= utt_remove_buf_file_callback,
-};
-
-static struct rchan_callbacks utt_relay_callbacks_global = {
-	.subbuf_start		= utt_subbuf_start_callback,
-	.create_buf_file	= utt_create_global_buf_file_callback,
-	.remove_buf_file	= utt_remove_buf_file_callback,
-};
-
-/*
- * Setup everything required to start tracing
- */
-static struct utt_trace *utt_trace_setup(struct utt_trace_setup *utts)
-{
-	struct utt_trace *utt = NULL;
-	struct dentry *dir = NULL;
-	int ret = -EINVAL;
-	u64 npages;
-	struct sysinfo si;
-
-	if (!utts->buf_size || !utts->buf_nr)
-		goto err;
-
-	ret = -ENOMEM;
-	utt = _stp_kzalloc(sizeof(*utt));
-	if (!utt)
-		goto err;
-
-	ret = -ENOENT;
-	dir = utt_create_tree(utt, utts->root, utts->name);
-	if (!dir)
-		goto err;
-	utt->dir = dir;
-	atomic_set(&utt->dropped, 0);
-
-	ret = -EIO;
-	utt->dropped_file = debugfs_create_file("dropped", 0444, dir, utt, &utt_dropped_fops);
-	if (!utt->dropped_file)
-		goto err;
-
-	npages = utts->buf_size * utts->buf_nr;
-	if (!utts->is_global)
-		npages *= num_possible_cpus();
-	npages >>= PAGE_SHIFT;
-	si_meminfo(&si);
-#define MB(i) (unsigned long)((i) >> (20 - PAGE_SHIFT))
-	if (npages > (si.freeram + si.bufferram)) {
-		errk("Not enough free+buffered memory(%luMB) for log buffer(%luMB)\n",
-		     MB(si.freeram + si.bufferram),
-		     MB(npages));
-		ret = -ENOMEM;
-		goto err;
-	} else if (npages > si.freeram) {
-		/* exceeds freeram, but below freeram+bufferram */
-		printk(KERN_WARNING
-		       "log buffer size exceeds free memory(%luMB)\n",
-		       MB(si.freeram));
-	}
-
-#if (RELAYFS_CHANNEL_VERSION >= 7)
-	if (utts->is_global)
-		utt->rchan = relay_open("trace", dir, utts->buf_size, utts->buf_nr, 
-					&utt_relay_callbacks_global, NULL);
-	else
-		utt->rchan = relay_open("trace", dir, utts->buf_size, utts->buf_nr, 
-					&utt_relay_callbacks, NULL);
-#else
-	if (utts->is_global)
-		utt->rchan = relay_open("trace", dir, utts->buf_size, utts->buf_nr, &utt_relay_callbacks_global);
-	else
-		utt->rchan = relay_open("trace", dir, utts->buf_size, utts->buf_nr, &utt_relay_callbacks);
-#endif
-
-	if (!utt->rchan)
-		goto err;
-	utt->rchan->private_data = utt;
-
-	utt->is_global = utts->is_global;
-
-	utt->trace_state = Utt_trace_setup;
-
-	utts->err = 0;
-	return utt;
-err:
-	if (utt) {
-		if (utt->dropped_file)
-			debugfs_remove(utt->dropped_file);
-		if (utt->rchan)
-			relay_close(utt->rchan);
-		_stp_kfree(utt);
-	}
-	if (dir)
-		utt_remove_tree(utt);
-	utts->err = ret;
-	return NULL;
-}
-
-static int utt_trace_startstop(struct utt_trace *utt, int start,
-			unsigned int *trace_seq)
-{
-	int ret;
-
-	/*
-	 * For starting a trace, we can transition from a setup or stopped
-	 * trace. For stopping a trace, the state must be running
-	 */
-	ret = -EINVAL;
-	if (start) {
-		if (utt->trace_state == Utt_trace_setup ||
-		    utt->trace_state == Utt_trace_stopped) {
-			if (trace_seq)
-				(*trace_seq)++;
-			__utt_timer_init(utt);
-			smp_mb();
-			utt->trace_state = Utt_trace_running;
-			ret = 0;
-		}
-	} else {
-		if (utt->trace_state == Utt_trace_running) {
-			utt->trace_state = Utt_trace_stopped;
-			del_timer_sync(&utt->timer);
-			relay_flush(utt->rchan);
-			ret = 0;
-		}
-	}
-
-	return ret;
-}
diff --git a/runtime/transport/utt.h b/runtime/transport/utt.h
deleted file mode 100644
index 2a479d70..00000000
--- a/runtime/transport/utt.h
+++ /dev/null
@@ -1,83 +0,0 @@
-#ifndef UTT_H
-#define UTT_H
-
-enum {
-	Utt_trace_setup = 1,
-	Utt_trace_running,
-	Utt_trace_stopped,
-};
-
-struct utt_trace {
-	int trace_state;
-//	struct rchan *rchan;
-	struct dentry *dir;		/* systemtap/module_name */
-	struct dentry *dropped_file;
-	atomic_t dropped;
-	struct dentry *utt_tree_root;	/* systemtap */
-	void *private_data;
-	atomic_t wakeup;
-	struct timer_list timer;
-	int is_global;
-};
-
-#define UTT_TRACE_ROOT_NAME_SIZE	64	/* Largest string for a root dir identifier */
-#define UTT_TRACE_NAME_SIZE		64	/* Largest string for a trace identifier */
-
-#ifndef UTT_TIMER_INTERVAL
-#define UTT_TIMER_INTERVAL		((HZ + 99) / 100)	/* Wakeup timer interval in jiffies (default 10 ms)*/
-#endif
-
-/*
- * User setup structure
- */
-struct utt_trace_setup {
-	char root[UTT_TRACE_ROOT_NAME_SIZE];	/* input */
-	char name[UTT_TRACE_NAME_SIZE];		/* input */
-	u32 buf_size;				/* input */
-	u32 buf_nr;				/* input */
-	int is_global;				/* input */
-	int err;				/* output */
-};
-
-
-static struct utt_trace *utt_trace_setup(struct utt_trace_setup *utts);
-
-static int utt_trace_startstop(struct utt_trace *utt, int start,
-			       unsigned int *trace_seq);
-static void utt_trace_cleanup(struct utt_trace *utt);
-static int utt_trace_remove(struct utt_trace *utt);
-
-#if STP_TRANSPORT_VERSION == 2
-static size_t utt_switch_subbuf(struct utt_trace *utt, struct rchan_buf *buf,
-				size_t length);
-/**
- *      utt_reserve - reserve slot in channel buffer
- *      @utt: utt channel
- *      @length: number of bytes to reserve
- *
- *      Returns pointer to reserved slot, NULL if full.
- *
- *      This function is utt_switch_subbuf version of relay_reserve.
- */
-static inline void *utt_reserve(struct utt_trace *utt, size_t length)
-{
-#if 0
-	void *reserved;
-	struct rchan_buf *buf = utt->rchan->buf[smp_processor_id()];
-
-	if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
-		length = utt_switch_subbuf(utt, buf, length);
-		if (!length)
-			return NULL;
-	}
-	reserved = (char*)buf->data + buf->offset;
-	buf->offset += length;
-
-	return reserved;
-#else
-	return NULL;
-#endif
-}
-#endif
-
-#endif