Add kprobes support
[lttng-modules.git] / ltt-debugfs-abi.c
index 5582fcc4fbfc8f17716673792d8164e250bba4aa..d013fa5a86a4e1fd33507ceff92dab0c509386de 100644 (file)
  *     - Takes instrumentation source specific arguments.
  */
 
+#include <linux/module.h>
 #include <linux/debugfs.h>
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include "wrapper/vmalloc.h"   /* for wrapper_vmalloc_sync_all() */
+#include "wrapper/ringbuffer/vfs.h"
+#include "ltt-debugfs-abi.h"
 #include "ltt-events.h"
+#include "ltt-tracer.h"
 
 /*
  * This is LTTng's own personal way to create a system call as an external
@@ -34,47 +43,38 @@ 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;
 
-/*
- * LTTng DebugFS ABI structures.
- */
-
-struct lttng_channel {
-       int overwrite;                  /* 1: overwrite, 0: discard */
-       u64 subbuf_size;
-       u64 num_subbuf;
-       unsigned int switch_timer_interval;
-       unsigned int read_timer_interval;
-};
-
-struct lttng_event {
-       enum instrum_type itype;
-       char name[];
+enum channel_type {
+       PER_CPU_CHANNEL,
+       METADATA_CHANNEL,
 };
 
 static
 int lttng_abi_create_session(void)
 {
        struct ltt_session *session;
-       struct file *session_filp;
-       int session_fd;
+       struct file *session_file;
+       int session_fd, ret;
 
        session = ltt_session_create();
        if (!session)
                return -ENOMEM;
-       session_fd = get_unused_fd_flags(O_RDWR);
+       session_fd = get_unused_fd();
        if (session_fd < 0) {
                ret = session_fd;
                goto fd_error;
        }
-       session_filp = anon_inode_getfile("[lttng_session]",
+       session_file = anon_inode_getfile("[lttng_session]",
                                          &lttng_session_fops,
                                          session, O_RDWR);
-       if (IS_ERR(session_filp)) {
-               ret = PTR_ERR(session_filp);
+       if (IS_ERR(session_file)) {
+               ret = PTR_ERR(session_file);
                goto file_error;
        }
-       fd_install(session_fd, session_filp);
+       session->file = session_file;
+       fd_install(session_fd, session_file);
        return session_fd;
 
 file_error:
@@ -84,25 +84,43 @@ fd_error:
        return ret;
 }
 
+static
+long lttng_abi_tracer_version(struct file *file, 
+       struct lttng_kernel_tracer_version __user *uversion_param)
+{
+       struct lttng_kernel_tracer_version v;
+
+       v.version = LTTNG_VERSION;
+       v.patchlevel = LTTNG_PATCHLEVEL;
+       v.sublevel = LTTNG_SUBLEVEL;
+
+       if (copy_to_user(uversion_param, &v, sizeof(v)))
+               return -EFAULT;
+       return 0;
+}
+
 /**
  *     lttng_ioctl - lttng syscall through ioctl
  *
- *     @filp: the file
+ *     @file: the file
  *     @cmd: the command
  *     @arg: command arg
  *
  *     This ioctl implements lttng commands:
- *     LTTNG_SESSION
+ *     LTTNG_KERNEL_SESSION
  *             Returns a LTTng trace session file descriptor
  *
  * The returned session will be deleted when its file descriptor is closed.
  */
 static
-long lttng_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
        switch (cmd) {
-       case LTTNG_SESSION:
+       case LTTNG_KERNEL_SESSION:
                return lttng_abi_create_session();
+       case LTTNG_KERNEL_TRACER_VERSION:
+               return lttng_abi_tracer_version(file,
+                               (struct lttng_kernel_tracer_version __user *) arg);
        default:
                return -ENOIOCTLCMD;
        }
@@ -113,54 +131,116 @@ static const struct file_operations lttng_fops = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl = lttng_ioctl,
 #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";
+       const struct lttng_event_desc *event_desc;
+       struct ltt_event *event;
+       int ret;
+
+       event_desc = ltt_event_get(event_name);
+       if (!event_desc) {
+               ret = -ENOENT;
+               goto get_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, LTTNG_KERNEL_TRACEPOINTS,
+                                event_desc, NULL);
+       if (!event) {
+               goto create_error;
+               ret = -EEXIST;
+       }
+       return;
+
+create_error:
+       ltt_event_put(event_desc);
+get_error:
+       WARN_ON(1);
+       return;         /* not allowed to return error */
 }
 
-int lttng_abi_create_channel(struct file *session_filp,
-                            struct lttng_channel __user *uchan_param)
+static
+int lttng_abi_create_channel(struct file *session_file,
+                            struct lttng_kernel_channel __user *uchan_param,
+                            enum channel_type channel_type)
 {
-       struct ltt_session *session = session_filp->private_data;
+       struct ltt_session *session = session_file->private_data;
+       const struct file_operations *fops;
+       const char *transport_name;
        struct ltt_channel *chan;
-       struct file *chan_filp;
-       struct lttng_channel chan_param;
+       struct file *chan_file;
+       struct lttng_kernel_channel chan_param;
        int chan_fd;
        int ret = 0;
 
        if (copy_from_user(&chan_param, uchan_param, sizeof(chan_param)))
                return -EFAULT;
-       chan_fd = get_unused_fd_flags(O_RDWR);
+       chan_fd = get_unused_fd();
        if (chan_fd < 0) {
                ret = chan_fd;
                goto fd_error;
        }
-       chan_filp = anon_inode_getfile("[lttng_channel]",
+       chan_file = anon_inode_getfile("[lttng_channel]",
                                       &lttng_channel_fops,
                                       NULL, O_RDWR);
-       if (IS_ERR(chan_filp)) {
-               ret = PTR_ERR(chan_filp);
+       if (IS_ERR(chan_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 = &lttng_channel_fops;
+               break;
+       case METADATA_CHANNEL:
+               transport_name = "relay-metadata";
+               fops = &lttng_metadata_fops;
+               break;
+       default:
+               transport_name = "<unknown>";
+               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_param->subbuf_size,
-                                 chan_param->num_subbuf,
-                                 chan_param->switch_timer_interval,
-                                 chan_param->read_timer_interval);
+       chan = ltt_channel_create(session, transport_name, NULL,
+                                 chan_param.subbuf_size,
+                                 chan_param.num_subbuf,
+                                 chan_param.switch_timer_interval,
+                                 chan_param.read_timer_interval);
        if (!chan) {
-               ret = -ENOMEM;
+               ret = -EINVAL;
                goto chan_error;
        }
-       chan_filp->private_data = chan;
-       fd_install(chan_fd, chan_filp);
+       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);
+               session->metadata = chan;
+       }
+
        /* The channel created holds a reference on the session */
-       atomic_inc(&session_filp->f_count);
+       atomic_long_inc(&session_file->f_count);
 
        return chan_fd;
 
 chan_error:
-       fput(chan_filp);
+       fput(chan_file);
 file_error:
        put_unused_fd(chan_fd);
 fd_error:
@@ -170,22 +250,34 @@ fd_error:
 /**
  *     lttng_session_ioctl - lttng session fd ioctl
  *
- *     @filp: the file
+ *     @file: the file
  *     @cmd: the command
  *     @arg: command arg
  *
  *     This ioctl implements lttng commands:
- *     LTTNG_CHANNEL
+ *     LTTNG_KERNEL_CHANNEL
  *             Returns a LTTng channel file descriptor
  *
  * The returned channel will be deleted when its file descriptor is closed.
  */
 static
-long lttng_session_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
+       struct ltt_session *session = file->private_data;
+
        switch (cmd) {
-       case LTTNG_CHANNEL:
-               return lttng_abi_create_channel(filp, (struct lttng_channel __user *)arg);
+       case LTTNG_KERNEL_CHANNEL:
+               return lttng_abi_create_channel(file,
+                               (struct lttng_kernel_channel __user *) arg,
+                               PER_CPU_CHANNEL);
+       case LTTNG_KERNEL_SESSION_START:
+               return ltt_session_start(session);
+       case LTTNG_KERNEL_SESSION_STOP:
+               return ltt_session_stop(session);
+       case LTTNG_KERNEL_METADATA:
+               return lttng_abi_create_channel(file,
+                               (struct lttng_kernel_channel __user *) arg,
+                               METADATA_CHANNEL);
        default:
                return -ENOIOCTLCMD;
        }
@@ -203,7 +295,10 @@ static
 int lttng_session_release(struct inode *inode, struct file *file)
 {
        struct ltt_session *session = file->private_data;
-       return ltt_session_destroy(session);
+
+       if (session)
+               ltt_session_destroy(session);
+       return 0;
 }
 
 static const struct file_operations lttng_session_fops = {
@@ -212,96 +307,117 @@ static const struct file_operations lttng_session_fops = {
 #ifdef CONFIG_COMPAT
        .compat_ioctl = lttng_session_ioctl,
 #endif
-}
+};
 
 static
-int lttng_abi_open_stream(struct file *channel_filp)
+int lttng_abi_open_stream(struct file *channel_file)
 {
-       struct ltt_channel *channel = channel_filp->private_data;
+       struct ltt_channel *channel = channel_file->private_data;
        struct lib_ring_buffer *buf;
        int stream_fd, ret;
+       struct file *stream_file;
 
-       buf = ltt_buffer_read_open(channel->chan);
+       buf = channel->ops->buffer_read_open(channel->chan);
        if (!buf)
                return -ENOENT;
 
-       stream_fd = get_unused_fd_flags(O_RDWR);
+       stream_fd = get_unused_fd();
        if (stream_fd < 0) {
                ret = stream_fd;
                goto fd_error;
        }
-       stream_filp = anon_inode_getfile("[lttng_stream]",
+       stream_file = anon_inode_getfile("[lttng_stream]",
                                         &lib_ring_buffer_file_operations,
                                         buf, O_RDWR);
-       if (IS_ERR(stream_filp)) {
-               ret = PTR_ERR(stream_filp);
+       if (IS_ERR(stream_file)) {
+               ret = PTR_ERR(stream_file);
                goto file_error;
        }
-       fd_install(stream_fd, stream_filp);
-       /* The stream holds a reference on the channel */
-       atomic_inc(&channel_filp->f_count);
+       /*
+        * OPEN_FMODE, called within anon_inode_getfile/alloc_file, don't honor
+        * FMODE_LSEEK, FMODE_PREAD nor FMODE_PWRITE. We need to read from this
+        * file descriptor, so we set FMODE_PREAD here.
+        */
+       stream_file->f_mode |= FMODE_PREAD;
+       fd_install(stream_fd, stream_file);
+       /*
+        * The stream holds a reference to the channel within the generic ring
+        * buffer library, so no need to hold a refcount on the channel and
+        * session files here.
+        */
        return stream_fd;
 
 file_error:
        put_unused_fd(stream_fd);
 fd_error:
-       ltt_buffer_read_close(buf);
+       channel->ops->buffer_read_close(buf);
        return ret;
 }
 
 static
-int lttng_abi_create_event(struct file *channel_filp,
-                          struct lttng_event __user *uevent_param)
+int lttng_abi_create_event(struct file *channel_file,
+                          struct lttng_kernel_event __user *uevent_param)
 {
-       struct ltt_channel *channel = channel_filp->private_data;
+       struct ltt_channel *channel = channel_file->private_data;
+       const struct lttng_event_desc *event_desc;
        struct ltt_event *event;
        char *event_name;
-       struct lttng_event event_param;
+       struct lttng_kernel_event event_param;
        int event_fd, ret;
+       struct file *event_file;
 
        if (copy_from_user(&event_param, uevent_param, sizeof(event_param)))
                return -EFAULT;
        event_name = kmalloc(PATH_MAX, GFP_KERNEL);
        if (!event_name)
                return -ENOMEM;
-       if (strncpy_from_user(event_name, &uevent_param->name, PATH_MAX)) {
+       if (strncpy_from_user(event_name, uevent_param->name, PATH_MAX) < 0) {
                ret = -EFAULT;
                goto name_error;
        }
        event_name[PATH_MAX - 1] = '\0';
-       event_fd = get_unused_fd_flags(O_RDWR);
+
+       event_desc = ltt_event_get(event_name);
+       if (!event_desc) {
+               ret = -ENOENT;
+               goto get_error;
+       }
+       event_fd = get_unused_fd();
        if (event_fd < 0) {
                ret = event_fd;
                goto fd_error;
        }
-       event_filp = anon_inode_getfile("[lttng_event]",
+       event_file = anon_inode_getfile("[lttng_event]",
                                        &lttng_event_fops,
                                        NULL, O_RDWR);
-       if (IS_ERR(event_filp)) {
-               ret = PTR_ERR(event_filp);
+       if (IS_ERR(event_file)) {
+               ret = PTR_ERR(event_file);
                goto file_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_param->itype, event_name, NULL);
+       event = ltt_event_create(channel, event_name, &event_param,
+                                event_desc, NULL);
        if (!event) {
-               goto event_error;
                ret = -EEXIST;
+               goto event_error;
        }
-       event_filp->private_data = event;
-       fd_install(event_fd, event_filp);
+       event_file->private_data = event;
+       fd_install(event_fd, event_file);
        /* The event holds a reference on the channel */
-       atomic_inc(&channel_filp->f_count);
+       atomic_long_inc(&channel_file->f_count);
        kfree(event_name);
        return event_fd;
 
 event_error:
-       fput(event_filp);
+       fput(event_file);
 file_error:
        put_unused_fd(event_fd);
 fd_error:
+       ltt_event_put(event_desc);
+get_error:
 name_error:
        kfree(event_name);
        return ret;
@@ -310,47 +426,72 @@ name_error:
 /**
  *     lttng_channel_ioctl - lttng syscall through ioctl
  *
- *     @filp: the file
+ *     @file: the file
  *     @cmd: the command
  *     @arg: command arg
  *
  *     This ioctl implements lttng commands:
- *      LTTNG_STREAM
+ *      LTTNG_KERNEL_STREAM
  *              Returns an event stream file descriptor or failure.
  *              (typically, one event stream records events from one CPU)
- *     LTTNG_EVENT
+ *     LTTNG_KERNEL_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
-long lttng_channel_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+long lttng_channel_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+       switch (cmd) {
+       case LTTNG_KERNEL_STREAM:
+               return lttng_abi_open_stream(file);
+       case LTTNG_KERNEL_EVENT:
+               return lttng_abi_create_event(file, (struct lttng_kernel_event __user *) arg);
+       default:
+               return -ENOIOCTLCMD;
+       }
+}
+
+/**
+ *     lttng_metadata_ioctl - lttng syscall through ioctl
+ *
+ *     @file: the file
+ *     @cmd: the command
+ *     @arg: command arg
+ *
+ *     This ioctl implements lttng commands:
+ *      LTTNG_KERNEL_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(filp);
-       case LTTNG_EVENT:
-               return lttng_abi_create_event(filp, (struct lttng_event __user *)arg);
+       case LTTNG_KERNEL_STREAM:
+               return lttng_abi_open_stream(file);
        default:
                return -ENOIOCTLCMD;
        }
 }
 
+/* TODO: poll */
+#if 0
 /**
  *     lttng_channel_poll - lttng stream addition/removal monitoring
  *
- *     @filp: the file
+ *     @file: the file
  *     @wait: poll table
  */
-unsigned int lttng_channel_poll(struct file *filp, poll_table *wait)
+unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
 {
-       struct ltt_channel *channel = filp->private_data;
+       struct ltt_channel *channel = file->private_data;
        unsigned int mask = 0;
 
-       if (filp->f_mode & FMODE_READ) {
+       if (file->f_mode & FMODE_READ) {
                poll_wait_set_exclusive(wait);
-               poll_wait(filp, &channel->notify_wait, wait);
+               poll_wait(file, &channel->notify_wait, wait);
 
                /* TODO: identify when the channel is being finalized. */
                if (finalized)
@@ -361,22 +502,63 @@ unsigned int lttng_channel_poll(struct file *filp, poll_table *wait)
        return mask;
 
 }
+#endif //0
+
+static
+int lttng_channel_release(struct inode *inode, struct file *file)
+{
+       struct ltt_channel *channel = file->private_data;
+
+       if (channel)
+               fput(channel->session->file);
+       return 0;
+}
 
 static const struct file_operations lttng_channel_fops = {
        .release = lttng_channel_release,
+/* TODO */
+#if 0
        .poll = lttng_channel_poll,
+#endif //0
        .unlocked_ioctl = lttng_channel_ioctl,
 #ifdef CONFIG_COMPAT
        .compat_ioctl = lttng_channel_ioctl,
 #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)
+{
+       struct ltt_event *event = file->private_data;
+
+       if (event) {
+               ltt_event_unregister(event);
+               fput(event->chan->file);
+       }
+       return 0;
 }
 
-static int __init ltt_debugfs_abi_init(void)
+/* TODO: filter control ioctl */
+static const struct file_operations lttng_event_fops = {
+       .release = lttng_event_release,
+};
+
+int __init ltt_debugfs_abi_init(void)
 {
        int ret = 0;
 
-       lttng_dentry = debugfs_create_file("lttng", NULL);
-       if (IS_ERR(lttng_dentry) || !lttng_dentry)
+       wrapper_vmalloc_sync_all();
+       lttng_dentry = debugfs_create_file("lttng", S_IWUSR, NULL, NULL,
+                                          &lttng_fops);
+       if (IS_ERR(lttng_dentry) || !lttng_dentry) {
                printk(KERN_ERR "Error creating LTTng control file\n");
                ret = -ENOMEM;
                goto error;
@@ -385,7 +567,7 @@ error:
        return ret;
 }
 
-static void __exit ltt_debugfs_abi_exit(void)
+void __exit ltt_debugfs_abi_exit(void)
 {
-       debugfs_remote(lttng_dentry);
+       debugfs_remove(lttng_dentry);
 }
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