/* * uprobes-based tracing events * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA * * Copyright (C) IBM Corporation, 2010-2012 * Author:	Srikar Dronamraju <srikar@linux.vnet.ibm.com> */#define pr_fmt(fmt)	"trace_kprobe: " fmt #include <linux/module.h>#include <linux/uaccess.h>#include <linux/uprobes.h>#include <linux/namei.h>#include <linux/string.h>#include <linux/rculist.h> #include "trace_probe.h" #define UPROBE_EVENT_SYSTEM	"uprobes" struct uprobe_trace_entry_head {	struct trace_entry	ent;	unsigned long		vaddr[];}; #define SIZEOF_TRACE_ENTRY(is_return)			\	(sizeof(struct uprobe_trace_entry_head) +	\	 sizeof(unsigned long) * (is_return ? 2 : 1)) #define DATAOF_TRACE_ENTRY(entry, is_return)		\	((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) struct trace_uprobe_filter {	rwlock_t		rwlock;	int			nr_systemwide;	struct list_head	perf_events;}; /* * uprobe event core functions */struct trace_uprobe {	struct list_head		list;	struct trace_uprobe_filter	filter;	struct uprobe_consumer		consumer;	struct inode			*inode;	char				*filename;	unsigned long			offset;	unsigned long			nhit;	struct trace_probe		tp;}; #define SIZEOF_TRACE_UPROBE(n)				\	(offsetof(struct trace_uprobe, tp.args) +	\	(sizeof(struct probe_arg) * (n))) static int register_uprobe_event(struct trace_uprobe *tu);static int unregister_uprobe_event(struct trace_uprobe *tu); static DEFINE_MUTEX(uprobe_lock);static LIST_HEAD(uprobe_list); struct uprobe_dispatch_data {	struct trace_uprobe	*tu;	unsigned long		bp_addr;}; static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);static int uretprobe_dispatcher(struct uprobe_consumer *con,				unsigned long func, struct pt_regs *regs); #ifdef CONFIG_STACK_GROWSUPstatic unsigned long adjust_stack_addr(unsigned long addr, unsigned int n){	return addr - (n * sizeof(long));}#elsestatic unsigned long adjust_stack_addr(unsigned long addr, unsigned int n){	return addr + (n * sizeof(long));}#endif static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n){	unsigned long ret;	unsigned long addr = user_stack_pointer(regs); 	addr = adjust_stack_addr(addr, n); 	if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))		return 0; 	return ret;} /* * Uprobes-specific fetch functions */#define DEFINE_FETCH_stack(type)					\static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,		\					 void *offset, void *dest)	\{									\	*(type *)dest = (type)get_user_stack_nth(regs,			\					      ((unsigned long)offset)); \}DEFINE_BASIC_FETCH_FUNCS(stack)/* No string on the stack entry */#define fetch_stack_string	NULL#define fetch_stack_string_size	NULL #define DEFINE_FETCH_memory(type)					\static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,		\					  void *addr, void *dest)	\{									\	type retval;							\	void __user *vaddr = (void __force __user *) addr;		\									\	if (copy_from_user(&retval, vaddr, sizeof(type)))		\		*(type *)dest = 0;					\	else								\		*(type *) dest = retval;				\}DEFINE_BASIC_FETCH_FUNCS(memory)/* * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max * length and relative data location. */static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,					    void *addr, void *dest){	long ret;	u32 rloc = *(u32 *)dest;	int maxlen  = get_rloc_len(rloc);	u8 *dst = get_rloc_data(dest);	void __user *src = (void __force __user *) addr; 	if (!maxlen)		return; 	ret = strncpy_from_user(dst, src, maxlen); 	if (ret < 0) {	/* Failed to fetch string */		((u8 *)get_rloc_data(dest))[0] = '\0';		*(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc));	} else {		*(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc));	}} static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,						 void *addr, void *dest){	int len;	void __user *vaddr = (void __force __user *) addr; 	len = strnlen_user(vaddr, MAX_STRING_SIZE); 	if (len == 0 || len > MAX_STRING_SIZE)  /* Failed to check length */		*(u32 *)dest = 0;	else		*(u32 *)dest = len;} static unsigned long translate_user_vaddr(void *file_offset){	unsigned long base_addr;	struct uprobe_dispatch_data *udd; 	udd = (void *) current->utask->vaddr; 	base_addr = udd->bp_addr - udd->tu->offset;	return base_addr + (unsigned long)file_offset;} #define DEFINE_FETCH_file_offset(type)					\static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs,	\					       void *offset, void *dest)\{									\	void *vaddr = (void *)translate_user_vaddr(offset);		\									\	FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest);		\}DEFINE_BASIC_FETCH_FUNCS(file_offset)DEFINE_FETCH_file_offset(string)DEFINE_FETCH_file_offset(string_size) /* Fetch type information table */static const struct fetch_type uprobes_fetch_type_table[] = {	/* Special types */	[FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,					sizeof(u32), 1, "__data_loc char[]"),	[FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,					string_size, sizeof(u32), 0, "u32"),	/* Basic types */	ASSIGN_FETCH_TYPE(u8,  u8,  0),	ASSIGN_FETCH_TYPE(u16, u16, 0),	ASSIGN_FETCH_TYPE(u32, u32, 0),	ASSIGN_FETCH_TYPE(u64, u64, 0),	ASSIGN_FETCH_TYPE(s8,  u8,  1),	ASSIGN_FETCH_TYPE(s16, u16, 1),	ASSIGN_FETCH_TYPE(s32, u32, 1),	ASSIGN_FETCH_TYPE(s64, u64, 1),	ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),	ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),	ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),	ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 	ASSIGN_FETCH_TYPE_END}; static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter){	rwlock_init(&filter->rwlock);	filter->nr_systemwide = 0;	INIT_LIST_HEAD(&filter->perf_events);} static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter){	return !filter->nr_systemwide && list_empty(&filter->perf_events);} static inline bool is_ret_probe(struct trace_uprobe *tu){	return tu->consumer.ret_handler != NULL;} /* * Allocate new trace_uprobe and initialize it (including uprobes). */static struct trace_uprobe *alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret){	struct trace_uprobe *tu; 	if (!event || !is_good_name(event))		return ERR_PTR(-EINVAL); 	if (!group || !is_good_name(group))		return ERR_PTR(-EINVAL); 	tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);	if (!tu)		return ERR_PTR(-ENOMEM); 	tu->tp.call.class = &tu->tp.class;	tu->tp.call.name = kstrdup(event, GFP_KERNEL);	if (!tu->tp.call.name)		goto error; 	tu->tp.class.system = kstrdup(group, GFP_KERNEL);	if (!tu->tp.class.system)		goto error; 	INIT_LIST_HEAD(&tu->list);	INIT_LIST_HEAD(&tu->tp.files);	tu->consumer.handler = uprobe_dispatcher;	if (is_ret)		tu->consumer.ret_handler = uretprobe_dispatcher;	init_trace_uprobe_filter(&tu->filter);	return tu; error:	kfree(tu->tp.call.name);	kfree(tu); 	return ERR_PTR(-ENOMEM);} static void free_trace_uprobe(struct trace_uprobe *tu){	int i; 	for (i = 0; i < tu->tp.nr_args; i++)		traceprobe_free_probe_arg(&tu->tp.args[i]); 	iput(tu->inode);	kfree(tu->tp.call.class->system);	kfree(tu->tp.call.name);	kfree(tu->filename);	kfree(tu);} static struct trace_uprobe *find_probe_event(const char *event, const char *group){	struct trace_uprobe *tu; 	list_for_each_entry(tu, &uprobe_list, list)		if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&		    strcmp(tu->tp.call.class->system, group) == 0)			return tu; 	return NULL;} /* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */static int unregister_trace_uprobe(struct trace_uprobe *tu){	int ret; 	ret = unregister_uprobe_event(tu);	if (ret)		return ret; 	list_del(&tu->list);	free_trace_uprobe(tu);	return 0;} /* Register a trace_uprobe and probe_event */static int register_trace_uprobe(struct trace_uprobe *tu){	struct trace_uprobe *old_tu;	int ret; 	mutex_lock(&uprobe_lock); 	/* register as an event */	old_tu = find_probe_event(trace_event_name(&tu->tp.call),			tu->tp.call.class->system);	if (old_tu) {		/* delete old event */		ret = unregister_trace_uprobe(old_tu);		if (ret)			goto end;	} 	ret = register_uprobe_event(tu);	if (ret) {		pr_warn("Failed to register probe event(%d)\n", ret);		goto end;	} 	list_add_tail(&tu->list, &uprobe_list); end:	mutex_unlock(&uprobe_lock); 	return ret;} /* * Argument syntax: *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] * *  - Remove uprobe: -:[GRP/]EVENT */static int create_trace_uprobe(int argc, char **argv){	struct trace_uprobe *tu;	struct inode *inode;	char *arg, *event, *group, *filename;	char buf[MAX_EVENT_NAME_LEN];	struct path path;	unsigned long offset;	bool is_delete, is_return;	int i, ret; 	inode = NULL;	ret = 0;	is_delete = false;	is_return = false;	event = NULL;	group = NULL; 	/* argc must be >= 1 */	if (argv[0][0] == '-')		is_delete = true;	else if (argv[0][0] == 'r')		is_return = true;	else if (argv[0][0] != 'p') {		pr_info("Probe definition must be started with 'p', 'r' or '-'.\n");		return -EINVAL;	} 	if (argv[0][1] == ':') {		event = &argv[0][2];		arg = strchr(event, '/'); 		if (arg) {			group = event;			event = arg + 1;			event[-1] = '\0'; 			if (strlen(group) == 0) {				pr_info("Group name is not specified\n");				return -EINVAL;			}		}		if (strlen(event) == 0) {			pr_info("Event name is not specified\n");			return -EINVAL;		}	}	if (!group)		group = UPROBE_EVENT_SYSTEM; 	if (is_delete) {		int ret; 		if (!event) {			pr_info("Delete command needs an event name.\n");			return -EINVAL;		}		mutex_lock(&uprobe_lock);		tu = find_probe_event(event, group); 		if (!tu) {			mutex_unlock(&uprobe_lock);			pr_info("Event %s/%s doesn't exist.\n", group, event);			return -ENOENT;		}		/* delete an event */		ret = unregister_trace_uprobe(tu);		mutex_unlock(&uprobe_lock);		return ret;	} 	if (argc < 2) {		pr_info("Probe point is not specified.\n");		return -EINVAL;	}	/* Find the last occurrence, in case the path contains ':' too. */	arg = strrchr(argv[1], ':');	if (!arg) {		ret = -EINVAL;		goto fail_address_parse;	} 	*arg++ = '\0';	filename = argv[1];	ret = kern_path(filename, LOOKUP_FOLLOW, &path);	if (ret)		goto fail_address_parse; 	inode = igrab(d_inode(path.dentry));	path_put(&path); 	if (!inode || !S_ISREG(inode->i_mode)) {		ret = -EINVAL;		goto fail_address_parse;	} 	ret = kstrtoul(arg, 0, &offset);	if (ret)		goto fail_address_parse; 	argc -= 2;	argv += 2; 	/* setup a probe */	if (!event) {		char *tail;		char *ptr; 		tail = kstrdup(kbasename(filename), GFP_KERNEL);		if (!tail) {			ret = -ENOMEM;			goto fail_address_parse;		} 		ptr = strpbrk(tail, ".-_");		if (ptr)			*ptr = '\0'; 		snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);		event = buf;		kfree(tail);	} 	tu = alloc_trace_uprobe(group, event, argc, is_return);	if (IS_ERR(tu)) {		pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));		ret = PTR_ERR(tu);		goto fail_address_parse;	}	tu->offset = offset;	tu->inode = inode;	tu->filename = kstrdup(filename, GFP_KERNEL); 	if (!tu->filename) {		pr_info("Failed to allocate filename.\n");		ret = -ENOMEM;		goto error;	} 	/* parse arguments */

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