// SPDX-License-Identifier: GPL-2.0/* * uprobes-based tracing events * * 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"#include "trace_probe_tmpl.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 path			path;	struct inode			*inode;	char				*filename;	unsigned long			offset;	unsigned long			ref_ctr_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 */static nokprobe_inline intprobe_mem_read(void *dest, void *src, size_t size){	void __user *vaddr = (void __force __user *)src; 	return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;}/* * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max * length and relative data location. */static nokprobe_inline intfetch_store_string(unsigned long addr, void *dest, void *base){	long ret;	u32 loc = *(u32 *)dest;	int maxlen  = get_loc_len(loc);	u8 *dst = get_loc_data(dest, base);	void __user *src = (void __force __user *) addr; 	if (unlikely(!maxlen))		return -ENOMEM; 	ret = strncpy_from_user(dst, src, maxlen);	if (ret >= 0) {		if (ret == maxlen)			dst[ret - 1] = '\0';		*(u32 *)dest = make_data_loc(ret, (void *)dst - base);	} 	return ret;} /* Return the length of string -- including null terminal byte */static nokprobe_inline intfetch_store_strlen(unsigned long addr){	int len;	void __user *vaddr = (void __force __user *) addr; 	len = strnlen_user(vaddr, MAX_STRING_SIZE); 	return (len > MAX_STRING_SIZE) ? 0 : len;} static unsigned long translate_user_vaddr(unsigned long 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 + file_offset;} /* Note that we don't verify it, since the code does not come from user space */static intprocess_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,		   void *base){	unsigned long val; 	/* 1st stage: get value from context */	switch (code->op) {	case FETCH_OP_REG:		val = regs_get_register(regs, code->param);		break;	case FETCH_OP_STACK:		val = get_user_stack_nth(regs, code->param);		break;	case FETCH_OP_STACKP:		val = user_stack_pointer(regs);		break;	case FETCH_OP_RETVAL:		val = regs_return_value(regs);		break;	case FETCH_OP_IMM:		val = code->immediate;		break;	case FETCH_OP_FOFFS:		val = translate_user_vaddr(code->immediate);		break;	default:		return -EILSEQ;	}	code++; 	return process_fetch_insn_bottom(code, val, dest, base);}NOKPROBE_SYMBOL(process_fetch_insn) 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]); 	path_put(&tu->path);	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;} /* * Uprobe with multiple reference counter is not allowed. i.e. * If inode and offset matches, reference counter offset *must* * match as well. Though, there is one exception: If user is * replacing old trace_uprobe with new one(same group/event), * then we allow same uprobe with new reference counter as far * as the new one does not conflict with any other existing * ones. */static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new){	struct trace_uprobe *tmp, *old = NULL;	struct inode *new_inode = d_real_inode(new->path.dentry); 	old = find_probe_event(trace_event_name(&new->tp.call),				new->tp.call.class->system); 	list_for_each_entry(tmp, &uprobe_list, list) {		if ((old ? old != tmp : true) &&		    new_inode == d_real_inode(tmp->path.dentry) &&		    new->offset == tmp->offset &&		    new->ref_ctr_offset != tmp->ref_ctr_offset) {			pr_warn("Reference counter offset mismatch.");			return ERR_PTR(-EINVAL);		}	}	return old;} /* 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_old_trace_uprobe(tu);	if (IS_ERR(old_tu)) {		ret = PTR_ERR(old_tu);		goto end;	} 	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;	char *arg, *event, *group, *filename, *rctr, *rctr_end;	char buf[MAX_EVENT_NAME_LEN];	struct path path;	unsigned long offset, ref_ctr_offset;	bool is_delete, is_return;	int i, ret; 	ret = 0;	is_delete = false;	is_return = false;	event = NULL;	group = NULL;	ref_ctr_offset = 0; 	/* 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)		return -EINVAL; 	*arg++ = '\0';	filename = argv[1];	ret = kern_path(filename, LOOKUP_FOLLOW, &path);	if (ret)		return ret; 	if (!d_is_reg(path.dentry)) {		ret = -EINVAL;		goto fail_address_parse;	} 	/* Parse reference counter offset if specified. */	rctr = strchr(arg, '(');	if (rctr) {		rctr_end = strchr(rctr, ')');		if (rctr > rctr_end || *(rctr_end + 1) != 0) {			ret = -EINVAL;			pr_info("Invalid reference counter offset.\n");			goto fail_address_parse;		} 		*rctr++ = '\0';		*rctr_end = '\0';		ret = kstrtoul(rctr, 0, &ref_ctr_offset);		if (ret) {			pr_info("Invalid reference counter offset.\n");			goto fail_address_parse;		}	} 	/* Parse uprobe offset. */	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);	}

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