From 5dbbdb433f181be8b3c30e8cd03191b5408614ca Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Tue, 10 May 2011 14:37:41 -0400 Subject: [PATCH] Add METADATA ioctl Signed-off-by: Mathieu Desnoyers --- ltt-debugfs-abi.c | 116 ++++++++++++++++++++++++++++++++++++++++++++-- ltt-debugfs-abi.h | 1 + ltt-events.c | 5 +- ltt-events.h | 6 +++ 4 files changed, 121 insertions(+), 7 deletions(-) diff --git a/ltt-debugfs-abi.c b/ltt-debugfs-abi.c index 41774e43..340f7ddc 100644 --- a/ltt-debugfs-abi.c +++ b/ltt-debugfs-abi.c @@ -41,8 +41,15 @@ static struct dentry *lttng_dentry; static const struct file_operations lttng_fops; static const struct file_operations lttng_session_fops; static const struct file_operations lttng_channel_fops; +static const struct file_operations lttng_metadata_fops; static const struct file_operations lttng_event_fops; +enum channel_type { + PER_CPU_CHANNEL, + GLOBAL_CHANNEL, + METADATA_CHANNEL, +}; + static int lttng_abi_create_session(void) { @@ -107,10 +114,52 @@ static const struct file_operations lttng_fops = { #endif }; +/* + * We tolerate no failure in this function (if one happens, we print a dmesg + * error, but cannot return any error, because the channel information is + * invariant. + */ +static +void lttng_metadata_create_events(struct file *channel_file) +{ + struct ltt_channel *channel = channel_file->private_data; + char *event_name = "lttng-metadata"; + struct ltt_event *event; + int ret; + void *probe; + + probe = ltt_probe_get(event_name); + if (!probe) { + ret = -ENOENT; + goto probe_error; + } + /* + * We tolerate no failure path after event creation. It will stay + * invariant for the rest of the session. + */ + event = ltt_event_create(channel, event_name, INSTRUM_TRACEPOINTS, + probe, NULL); + if (!event) { + goto event_error; + ret = -EEXIST; + } + return; + +event_error: + ltt_probe_put(probe); +probe_error: + WARN_ON(1); + return; /* not allowed to return error */ +} + +static int lttng_abi_create_channel(struct file *session_file, - struct lttng_channel __user *uchan_param) + struct lttng_channel __user *uchan_param, + enum channel_type channel_type) { struct ltt_session *session = session_file->private_data; + const struct file_operations *fops; + const char *transport_name; struct ltt_channel *chan; struct file *chan_file; struct lttng_channel chan_param; @@ -131,11 +180,30 @@ int lttng_abi_create_channel(struct file *session_file, ret = PTR_ERR(chan_file); goto file_error; } + switch (channel_type) { + case PER_CPU_CHANNEL: + transport_name = chan_param.overwrite ? + "relay-overwrite" : "relay-discard"; + fops = <tng_channel_fops; + break; + case GLOBAL_CHANNEL: + transport_name = chan_param.overwrite ? + "global-relay-overwrite" : "global-relay-discard"; + fops = <tng_channel_fops; + break; + case METADATA_CHANNEL: + transport_name = "global-relay-discard"; + fops = <tng_metadata_fops; + break; + default: + transport_name = ""; + break; + } /* * We tolerate no failure path after channel creation. It will stay * invariant for the rest of the session. */ - chan = ltt_channel_create(session, chan_param.overwrite, NULL, + chan = ltt_channel_create(session, transport_name, NULL, chan_param.subbuf_size, chan_param.num_subbuf, chan_param.switch_timer_interval, @@ -147,6 +215,9 @@ int lttng_abi_create_channel(struct file *session_file, chan->file = chan_file; chan_file->private_data = chan; fd_install(chan_fd, chan_file); + if (channel_type == METADATA_CHANNEL) + lttng_metadata_create_events(chan_file); + /* The channel created holds a reference on the session */ atomic_long_inc(&session_file->f_count); @@ -180,11 +251,17 @@ long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg) switch (cmd) { case LTTNG_CHANNEL: - return lttng_abi_create_channel(file, (struct lttng_channel __user *)arg); + return lttng_abi_create_channel(file, + (struct lttng_channel __user *)arg, + PER_CPU_CHANNEL); case LTTNG_SESSION_START: return ltt_session_start(session); case LTTNG_SESSION_STOP: return ltt_session_stop(session); + case LTTNG_METADATA: + return lttng_abi_create_channel(file, + (struct lttng_channel __user *)arg, + METADATA_CHANNEL); default: return -ENOIOCTLCMD; } @@ -344,7 +421,6 @@ name_error: * LTTNG_EVENT * Returns an event file descriptor or failure. * - * The returned session will be deleted when its file descriptor is closed. * Channel and event file descriptors also hold a reference on the session. */ static @@ -360,6 +436,30 @@ long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } } +/** + * lttng_metadata_ioctl - lttng syscall through ioctl + * + * @file: the file + * @cmd: the command + * @arg: command arg + * + * This ioctl implements lttng commands: + * LTTNG_STREAM + * Returns an event stream file descriptor or failure. + * + * Channel and event file descriptors also hold a reference on the session. + */ +static +long lttng_metadata_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case LTTNG_STREAM: + return lttng_abi_open_stream(file); + default: + return -ENOIOCTLCMD; + } +} + /* TODO: poll */ #if 0 /** @@ -410,6 +510,14 @@ static const struct file_operations lttng_channel_fops = { #endif }; +static const struct file_operations lttng_metadata_fops = { + .release = lttng_channel_release, + .unlocked_ioctl = lttng_metadata_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = lttng_metadata_ioctl, +#endif +}; + static int lttng_event_release(struct inode *inode, struct file *file) { diff --git a/ltt-debugfs-abi.h b/ltt-debugfs-abi.h index a232e131..3a2af561 100644 --- a/ltt-debugfs-abi.h +++ b/ltt-debugfs-abi.h @@ -38,5 +38,6 @@ struct lttng_event { #define LTTNG_CHANNEL _IOW(0xF6, 0x43, struct lttng_channel) #define LTTNG_STREAM _IO(0xF6, 0x44) #define LTTNG_EVENT _IOW(0xF6, 0x45, struct lttng_event) +#define LTTNG_METADATA _IOW(0xF6, 0x46, struct lttng_channel) #endif /* _LTT_DEBUGFS_ABI_H */ diff --git a/ltt-events.c b/ltt-events.c index 947d772c..184f2daa 100644 --- a/ltt-events.c +++ b/ltt-events.c @@ -108,21 +108,20 @@ static struct ltt_transport *ltt_transport_find(char *name) } struct ltt_channel *ltt_channel_create(struct ltt_session *session, - int overwrite, void *buf_addr, + const char *transport_name, + void *buf_addr, size_t subbuf_size, size_t num_subbuf, unsigned int switch_timer_interval, unsigned int read_timer_interval) { struct ltt_channel *chan; struct ltt_transport *transport; - char *transport_name; mutex_lock(&sessions_mutex); if (session->active) { printk(KERN_WARNING "LTTng refusing to add channel to active session\n"); goto active; /* Refuse to add channel to active session */ } - transport_name = overwrite ? "relay-overwrite" : "relay-discard"; transport = ltt_transport_find(transport_name); if (!transport) { printk(KERN_WARNING "LTTng transport %s not found\n", diff --git a/ltt-events.h b/ltt-events.h index e8171b03..443d185c 100644 --- a/ltt-events.h +++ b/ltt-events.h @@ -78,6 +78,12 @@ int ltt_session_stop(struct ltt_session *session); void ltt_session_destroy(struct ltt_session *session); struct ltt_channel *ltt_channel_create(struct ltt_session *session, + const char *transport_name, + void *buf_addr, + size_t subbuf_size, size_t num_subbuf, + unsigned int switch_timer_interval, + unsigned int read_timer_interval); +struct ltt_channel *ltt_global_channel_create(struct ltt_session *session, int overwrite, void *buf_addr, size_t subbuf_size, size_t num_subbuf, unsigned int switch_timer_interval, -- 2.34.1