[ltt-dev] [PATCH] LTTng: Make mark-control work in debugfs

[guijianfeng@cn.fujitsu.com (Gui Jianfeng)]

Mathieu Desnoyers wrote:
> * Gui Jianfeng (guijianfeng at cn.fujitsu.com) wrote:
>> Hi Mathieu,
>>
>> This patch makes mark-control work in debugfs
>> Control files are organized as following.
>> ltt/
>> |-- markers
>> |   |-- fs
>> |   |   |-- buffer_wait_end
>> |   |   |   |-- enabled
>> |   |   |   `-- info
>> |   |   |-- buffer_wait_start
>> |   |   |   |-- enabled
>> |   |   |   `-- info
>> |   |   |-- close
>> |   |   |   |-- enabled
>> |   |   |   `-- info
>> |   |   |-- exec
>> |   |   |   |-- enabled
>> |   |   |   `-- info
>> ...
>>
>> One can enable or disable a marker by using the following command
>> # echo 1 > ltt/markers/fs/close/enabled
>> # echo 0 > ltt/markers/fs/close/enabled
>>
>> Show the marker information as following 
>> # cat ltt/markers/fs/close/info
>> format: "fd %u"
>> state: 1
>> event_id: 2
>> call: 0xc0459118
>> probe single : 0xc04f7b08
>>
> 
> Thanks a lot Gui, this is a very good patch. I'll make the cosmetic
> changes requested by scripts/checkpatch.pl myself and merge it. (please

  I see, thanks for pointing this out. :)

  BTW, I'll post a patch to modify user tools accordingly as soon as this patch
  has been merged into the new version of LTTng.

> get used to run it before submission, it's very good at spotting
> whitespaces at the end of lines and other coding style errors)
> 
> Best regards,
> 
> Mathieu
> 
>> Signed-off-by: Gui Jianfeng <guijianfeng at cn.fujitsu.com>
>> ---
>>  ltt/ltt-trace-control.c |  302 ++++++++++++++++++++++++++++++++++++++++++++++-
>>  1 files changed, 297 insertions(+), 5 deletions(-)
>>
>> diff --git a/ltt/ltt-trace-control.c b/ltt/ltt-trace-control.c
>> index 16502a2..e4676bf 100644
>> --- a/ltt/ltt-trace-control.c
>> +++ b/ltt/ltt-trace-control.c
>> @@ -1,8 +1,10 @@
>>  /*
>>   * LTT trace control module over debugfs.
>>   *
>> - * Copyright 2008 -
>> - *	Zhaolei <zhaolei at cn.fujitsu.com>
>> + * Copyright 2008 - Zhaolei <zhaolei at cn.fujitsu.com>
>> + *              
>> + * Copyright 2009 - Gui Jianfeng <guijianfeng at cn.fujitsu.com>
>> + *                  Make mark-control work in debugfs   
>>   */
>>  
>>  /*
>> @@ -16,14 +18,17 @@
>>  #include <linux/uaccess.h>
>>  #include <linux/debugfs.h>
>>  #include <linux/ltt-tracer.h>
>> +#include <linux/notifier.h>
>>  
>>  #define LTT_CONTROL_DIR "control"
>> +#define MARKERS_CONTROL_DIR "markers"
>>  #define LTT_SETUP_TRACE_FILE "setup_trace"
>>  #define LTT_DESTROY_TRACE_FILE "destroy_trace"
>>  
>>  #define LTT_WRITE_MAXLEN	(128)
>>  
>> -struct dentry *ltt_control_dir, *ltt_setup_trace_file, *ltt_destroy_trace_file;
>> +struct dentry *ltt_control_dir, *ltt_setup_trace_file, *ltt_destroy_trace_file,
>> +	*markers_control_dir;
>>  
>>  /*
>>   * the traces_lock nests inside control_lock.
>> @@ -692,6 +697,272 @@ static struct file_operations ltt_destroy_trace_operations = {
>>  	.write = destroy_trace_write,
>>  };
>>  
>> +static int marker_enabled_open(struct inode *inode, struct file *filp)
>> +{
>> +	filp->private_data = inode->i_private;
>> +	return 0;
>> +}
>> +
>> +static ssize_t marker_enabled_read(struct file *filp, char __user *ubuf,
>> +			    size_t cnt, loff_t *ppos)
>> +{
>> +	struct marker *marker;
>> +	char *buf;
>> +	int len;
>> +
>> +	marker = (struct marker *)filp->private_data;
>> +	buf = kmalloc(1024, GFP_KERNEL);
>> +
>> +	len = sprintf(buf, "%d\n", _imv_read(marker->state));
>> +
>> +	len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
>> +	kfree(buf);
>> +	
>> +	return len;
>> +}
>> +
>> +static ssize_t marker_enabled_write(struct file *filp, const char __user *ubuf,
>> +				size_t cnt, loff_t *ppos)
>> +{
>> +	char buf[NAME_MAX];
>> +	int buf_size;
>> +	int err = 0;
>> +	struct marker *marker;
>> +
>> +	marker = (struct marker *)filp->private_data;
>> +	buf_size = min(cnt, sizeof(buf) - 1);
>> +	err = copy_from_user(buf, ubuf, buf_size);
>> +	if (err)
>> +		return err;
>> +
>> +	buf[buf_size] = 0;
>> +
>> +	switch (buf[0]) {
>> +	case 'Y':
>> +	case 'y':
>> +	case '1':
>> +		err = ltt_marker_connect(marker->channel, marker->name, "default");
>> +		if (err)
>> +			return err;
>> +		break;
>> +	case 'N':
>> +	case 'n':
>> +	case '0':
>> +		err = ltt_marker_disconnect(marker->channel, marker->name,
>> +					    "default");
>> +		if (err)
>> +			return err;
>> +		break;
>> +	default:
>> +		return -EPERM;
>> +	}
>> +
>> +	return cnt;
>> +}
>> +
>> +static struct file_operations enabled_fops = {
>> +	.open = marker_enabled_open,
>> +	.read = marker_enabled_read,
>> +	.write = marker_enabled_write,
>> +};
>> +
>> +static int marker_info_open(struct inode *inode, struct file *filp)
>> +{
>> +	filp->private_data = inode->i_private;
>> +	return 0;
>> +}
>> +
>> +static ssize_t marker_info_read(struct file *filp, char __user *ubuf,
>> +			    size_t cnt, loff_t *ppos)
>> +{
>> +	struct marker *marker;
>> +	char *buf;
>> +	int len;
>> +
>> +	marker = (struct marker *)filp->private_data;
>> +	buf = kmalloc(1024, GFP_KERNEL);
>> +
>> +	len = sprintf(buf, "format: \"%s\"\nstate: %d\n"
>> +		      "event_id: %hu\n"
>> +		      "call: 0x%p\n"
>> +		      "probe %s : 0x%p\n",
>> +		      marker->format, _imv_read(marker->state), 
>> +		      marker->event_id, marker->call, marker->ptype ? 
>> +		      "multi" : "single", marker->ptype ?
>> +		      (void*)marker->multi : (void*)marker->single.func);
>> +
>> +	len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
>> +	kfree(buf);
>> +	
>> +	return len;
>> +}
>> +
>> +static struct file_operations info_fops = {
>> +	.open = marker_info_open,
>> +	.read = marker_info_read,
>> +};
>> +
>> +static int build_marker_file(struct marker *marker)
>> +{
>> +	struct dentry *channel_d, *marker_d, *enabled_d, *info_d;
>> +	int err;
>> +	
>> +	channel_d = dir_lookup(markers_control_dir, marker->channel);
>> +	if (!channel_d) {
>> +		channel_d = debugfs_create_dir(marker->channel,
>> +					       markers_control_dir);
>> +		if (IS_ERR(channel_d) || !channel_d) {
>> +			printk(KERN_ERR
>> +			       "%s: build channel dir of %s failed\n",
>> +			       __func__, marker->channel);
>> +			err = -ENOMEM;
>> +			goto err_build_fail;
>> +		}
>> +	}
>> +	
>> +	marker_d  = dir_lookup(channel_d, marker->name);
>> +	if (!marker_d) {
>> +		marker_d = debugfs_create_dir(marker->name, channel_d);
>> +		if (IS_ERR(marker_d) || !marker_d) {
>> +			printk(KERN_ERR
>> +			       "%s: marker dir of %s failed\n",
>> +			       __func__, marker->name);
>> +			err = -ENOMEM;
>> +			goto err_build_fail;
>> +		}
>> +	}
>> +	
>> +	enabled_d = dir_lookup(marker_d, "enabled");
>> +	if (!enabled_d) {
>> +		enabled_d = debugfs_create_file("enabled", 0644, marker_d,
>> +						marker, &enabled_fops);
>> +		if (IS_ERR(enabled_d) || !enabled_d) {
>> +			printk(KERN_ERR
>> +			       "%s: create file of %s failed\n",
>> +			       __func__, "enabled");
>> +			err = -ENOMEM;
>> +			goto err_build_fail;
>> +		}
>> +	}
>> +
>> +	info_d = dir_lookup(marker_d, "info");
>> +	if (!info_d) {
>> +		info_d = debugfs_create_file("info", 0444, marker_d,
>> +						marker, &info_fops);
>> +		if (IS_ERR(info_d) || !info_d) {
>> +			printk(KERN_ERR
>> +			       "%s: create file of %s failed\n",
>> +			       __func__, "enabled");
>> +			err = -ENOMEM;
>> +			goto err_build_fail;
>> +		}
>> +	}
>> +	
>> +	return 0;
>> +	
>> +err_build_fail:
>> +	return err;
>> +}
>> +
>> +static int build_marker_control_files(void)
>> +{
>> +	struct marker_iter iter;
>> +	int err;
>> +
>> +	err = 0;
>> +	if (!markers_control_dir)
>> +		return -EEXIST;
>> +
>> +	marker_iter_reset(&iter);
>> +	marker_iter_start(&iter);
>> +	for (; iter.marker != NULL; marker_iter_next(&iter)) {
>> +		err = build_marker_file(iter.marker);
>> +		if (err)
>> +			goto err_build_fail;
>> +	}
>> +	marker_iter_stop(&iter);
>> +	return 0;
>> +
>> +err_build_fail:
>> +	return err;
>> +}
>> +
>> +static int remove_marker_control_dir(struct marker *marker)
>> +{
>> +	struct dentry *channel_d, *marker_d;
>> +
>> +	channel_d = dir_lookup(markers_control_dir, marker->channel);
>> +	if (!channel_d)
>> +		return -ENOENT;
>> +	
>> +	marker_d = dir_lookup(channel_d, marker->name);
>> +	if (!marker_d)
>> +		return -ENOENT;
>> +	
>> +	debugfs_remove_recursive(marker_d);
>> +	if (list_empty(&channel_d->d_subdirs)) {
>> +		debugfs_remove(channel_d);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static void cleanup_control_dir(struct marker *begin, struct marker *end)
>> +{
>> +	struct marker *iter;
>> +
>> +	if (!markers_control_dir)
>> +		return;
>> +
>> +	for (iter = begin; iter < end; iter++) {
>> +		remove_marker_control_dir(iter);
>> +	}
>> +
>> +	return;
>> +}
>> +
>> +static void build_control_dir(struct marker *begin, struct marker *end)
>> +{
>> +	struct marker *iter;
>> +	int err;	
>> +
>> +	err = 0;
>> +	if (!markers_control_dir)
>> +		return;
>> +
>> +	for (iter = begin; iter < end; iter++) {
>> +		err = build_marker_file(iter);
>> +		if (err)
>> +			goto err_build_fail;
>> +	}
>> +
>> +	return;
>> +err_build_fail:
>> +	cleanup_control_dir(begin, end);
>> +	return;
>> +}
>> +
>> +static int module_notify(struct notifier_block *self,
>> +		  unsigned long val, void *data)
>> +{
>> +	struct module *mod = data;
>> +
>> +	switch (val) {
>> +	case MODULE_STATE_COMING:
>> +		build_control_dir(mod->markers,
>> +				  mod->markers + mod->num_markers);
>> +		break;
>> +	case MODULE_STATE_GOING:
>> +		cleanup_control_dir(mod->markers,
>> +				    mod->markers + mod->num_markers);
>> +		break;
>> +	}
>> +	return NOTIFY_DONE;
>> +}
>> +
>> +static struct notifier_block module_nb = {
>> +	.notifier_call = module_notify,
>> +};
>>  
>>  static int __init ltt_trace_control_init(void)
>>  {
>> @@ -733,8 +1004,27 @@ static int __init ltt_trace_control_init(void)
>>  		goto err_create_destroy_trace_file;
>>  	}
>>  
>> -	return 0;
>> -
>> +	markers_control_dir = debugfs_create_dir(MARKERS_CONTROL_DIR, 
>> +						 ltt_root_dentry);
>> +	if (IS_ERR(markers_control_dir) || !markers_control_dir) {
>> +		printk(KERN_ERR
>> +			"ltt_channel_control_init: create dir of %s failed\n",
>> +			MARKERS_CONTROL_DIR);
>> +		err = -ENOMEM;
>> +		goto err_create_marker_control_dir;
>> +	}
>> +	
>> +	if(build_marker_control_files())
>> +		goto err_build_fail;
>> +	
>> +	if (!register_module_notifier(&module_nb))
>> +		return 0;
>> +
>> +err_build_fail:
>> +	debugfs_remove_recursive(markers_control_dir);
>> +	markers_control_dir = NULL;
>> +err_create_marker_control_dir:
>> +	debugfs_remove(ltt_destroy_trace_file);
>>  err_create_destroy_trace_file:
>>  	debugfs_remove(ltt_setup_trace_file);
>>  err_create_setup_trace_file:
>> @@ -759,6 +1049,8 @@ static void __exit ltt_trace_control_exit(void)
>>  	debugfs_remove(ltt_setup_trace_file);
>>  	debugfs_remove(ltt_destroy_trace_file);
>>  	debugfs_remove_recursive(ltt_control_dir);
>> +	debugfs_remove_recursive(markers_control_dir);
>> +	unregister_module_notifier(&module_nb);
>>  }
>>  
>>  module_init(ltt_trace_control_init);
>> -- 
>> 1.5.4.rc3
>>
>>
>> _______________________________________________
>> ltt-dev mailing list
>> ltt-dev at lists.casi.polymtl.ca
>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>>
> 

-- 
Regards
Gui Jianfeng