uprobe: Support multiple call sites for the same uprobe event

[lttng-modules.git] / probes / lttng-uprobes.c

diff --git a/probes/lttng-uprobes.c b/probes/lttng-uprobes.c
index 1f549c2f34bb14660c3513953a5711c9aaddd693..47f3599f2baa336dd6c7e543a81aef5070b67efb 100644 (file)
--- a/probes/lttng-uprobes.c
+++ b/probes/lttng-uprobes.c
@@ -22,9 +22,11 @@
  */
 
 #include <linux/fdtable.h>
+#include <linux/list.h>
 #include <linux/module.h>
 #include <linux/namei.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 #include <lttng-events.h>
 #include <lttng-tracer.h>
 #include <wrapper/irqflags.h>
@@ -35,8 +37,9 @@
 static
 int lttng_uprobes_handler_pre(struct uprobe_consumer *uc, struct pt_regs *regs)
 {
-       struct lttng_event *event =
-               container_of(uc, struct lttng_event, u.uprobe.up_consumer);
+       struct lttng_uprobe_handler *uprobe_handler =
+               container_of(uc, struct lttng_uprobe_handler, up_consumer);
+       struct lttng_event *event = uprobe_handler->event;
        struct lttng_probe_ctx lttng_probe_ctx = {
                .event = event,
                .interruptible = !lttng_regs_irqs_disabled(regs),
@@ -151,12 +154,59 @@ error:
        return inode;
 }
 
-int lttng_uprobes_register(const char *name,
-                          int fd,
-                          uint64_t offset,
-                          struct lttng_event *event)
+int lttng_uprobes_add_callsite(struct lttng_event *event,
+       struct lttng_kernel_event_callsite __user *callsite)
 {
-       int ret;
+       int ret = 0;
+       struct lttng_uprobe_handler *uprobe_handler;
+
+       if (!event) {
+               ret = -EINVAL;
+               goto end;
+       }
+
+       uprobe_handler = kzalloc(sizeof(struct lttng_uprobe_handler), GFP_KERNEL);
+       if (!uprobe_handler) {
+               printk(KERN_WARNING "Error allocating uprobe_uprobe_handlers");
+               ret = -ENOMEM;
+               goto end;
+       }
+
+       /* Ensure the memory we just allocated don't trigger page faults. */
+       wrapper_vmalloc_sync_all();
+
+       uprobe_handler->event = event;
+       uprobe_handler->up_consumer.handler = lttng_uprobes_handler_pre;
+
+       ret = copy_from_user(&uprobe_handler->offset, &callsite->u.uprobe.offset, sizeof(uint64_t));
+       if (ret) {
+               goto register_error;
+       }
+
+       ret = wrapper_uprobe_register(event->u.uprobe.inode,
+                     uprobe_handler->offset, &uprobe_handler->up_consumer);
+       if (ret) {
+               printk(KERN_WARNING "Error registering probe on inode %lu "
+                      "and offset 0x%llx\n", event->u.uprobe.inode->i_ino,
+                      uprobe_handler->offset);
+               ret = -1;
+               goto register_error;
+       }
+
+       list_add(&uprobe_handler->node, &event->u.uprobe.head);
+
+       return ret;
+
+register_error:
+       kfree(uprobe_handler);
+end:
+       return ret;
+}
+EXPORT_SYMBOL_GPL(lttng_uprobes_add_callsite);
+
+int lttng_uprobes_register(const char *name, int fd, struct lttng_event *event)
+{
+       int ret = 0;
        struct inode *inode;
 
        ret = lttng_create_uprobe_event(name, event);
@@ -169,29 +219,11 @@ int lttng_uprobes_register(const char *name,
                ret = -EBADF;
                goto inode_error;
        }
-
-       memset(&event->u.uprobe.up_consumer, 0,
-              sizeof(event->u.uprobe.up_consumer));
-
-       event->u.uprobe.up_consumer.handler = lttng_uprobes_handler_pre;
        event->u.uprobe.inode = inode;
-       event->u.uprobe.offset = offset;
+       INIT_LIST_HEAD(&event->u.uprobe.head);
 
-        /* Ensure the memory we just allocated don't trigger page faults. */
-       wrapper_vmalloc_sync_all();
-       ret = wrapper_uprobe_register(event->u.uprobe.inode,
-                       event->u.uprobe.offset,
-                       &event->u.uprobe.up_consumer);
-       if (ret) {
-               printk(KERN_WARNING "Error registering probe on inode %lu "
-                      "and offset %llu\n", event->u.uprobe.inode->i_ino,
-                      event->u.uprobe.offset);
-               goto register_error;
-       }
        return 0;
 
-register_error:
-       iput(event->u.uprobe.inode);
 inode_error:
        kfree(event->desc->name);
        kfree(event->desc);
@@ -202,9 +234,18 @@ EXPORT_SYMBOL_GPL(lttng_uprobes_register);
 
 void lttng_uprobes_unregister(struct lttng_event *event)
 {
-       wrapper_uprobe_unregister(event->u.uprobe.inode,
-                       event->u.uprobe.offset,
-                       &event->u.uprobe.up_consumer);
+       struct lttng_uprobe_handler *iter, *tmp;
+
+       /*
+        * Iterate over the list of handler, remove each handler from the list
+        * and free the struct.
+        */
+       list_for_each_entry_safe(iter, tmp, &event->u.uprobe.head, node) {
+               wrapper_uprobe_unregister(event->u.uprobe.inode, iter->offset,
+                       &iter->up_consumer);
+               list_del(&iter->node);
+               kfree(iter);
+       }
 }
 EXPORT_SYMBOL_GPL(lttng_uprobes_unregister);