diff options
author | David S. Miller <davem@davemloft.net> | 2008-03-18 00:37:55 -0700 |
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committer | David S. Miller <davem@davemloft.net> | 2008-03-18 00:37:55 -0700 |
commit | 577f99c1d08cf9cbdafd4e858dd13ff04d855090 (patch) | |
tree | 0f726bbda9b18d311d4c95198bbd96cb7ac01db0 /samples/kprobes/jprobe_example.c | |
parent | 26c0f03f6b77c513cb7bc37b73a06819bdbb791b (diff) | |
parent | 2f633928cbba8a5858bb39b11e7219a41b0fbef5 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts:
drivers/net/wireless/rt2x00/rt2x00dev.c
net/8021q/vlan_dev.c
Diffstat (limited to 'samples/kprobes/jprobe_example.c')
-rw-r--r-- | samples/kprobes/jprobe_example.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/samples/kprobes/jprobe_example.c b/samples/kprobes/jprobe_example.c new file mode 100644 index 000000000000..b7541355b92b --- /dev/null +++ b/samples/kprobes/jprobe_example.c @@ -0,0 +1,68 @@ +/* + * Here's a sample kernel module showing the use of jprobes to dump + * the arguments of do_fork(). + * + * For more information on theory of operation of jprobes, see + * Documentation/kprobes.txt + * + * Build and insert the kernel module as done in the kprobe example. + * You will see the trace data in /var/log/messages and on the + * console whenever do_fork() is invoked to create a new process. + * (Some messages may be suppressed if syslogd is configured to + * eliminate duplicate messages.) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/kprobes.h> + +/* + * Jumper probe for do_fork. + * Mirror principle enables access to arguments of the probed routine + * from the probe handler. + */ + +/* Proxy routine having the same arguments as actual do_fork() routine */ +static long jdo_fork(unsigned long clone_flags, unsigned long stack_start, + struct pt_regs *regs, unsigned long stack_size, + int __user *parent_tidptr, int __user *child_tidptr) +{ + printk(KERN_INFO "jprobe: clone_flags = 0x%lx, stack_size = 0x%lx," + " regs = 0x%p\n", + clone_flags, stack_size, regs); + + /* Always end with a call to jprobe_return(). */ + jprobe_return(); + return 0; +} + +static struct jprobe my_jprobe = { + .entry = jdo_fork, + .kp = { + .symbol_name = "do_fork", + }, +}; + +static int __init jprobe_init(void) +{ + int ret; + + ret = register_jprobe(&my_jprobe); + if (ret < 0) { + printk(KERN_INFO "register_jprobe failed, returned %d\n", ret); + return -1; + } + printk(KERN_INFO "Planted jprobe at %p, handler addr %p\n", + my_jprobe.kp.addr, my_jprobe.entry); + return 0; +} + +static void __exit jprobe_exit(void) +{ + unregister_jprobe(&my_jprobe); + printk(KERN_INFO "jprobe at %p unregistered\n", my_jprobe.kp.addr); +} + +module_init(jprobe_init) +module_exit(jprobe_exit) +MODULE_LICENSE("GPL"); |