- 根目录:
- kernel
- trace
- trace_probe.c
/*
* Common code for probe-based Dynamic 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
*
* This code was copied from kernel/trace/trace_kprobe.c written by
* Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
*
* Updates to make this generic:
* Copyright (C) IBM Corporation, 2010-2011
* Author: Srikar Dronamraju
*/
#include "trace_probe.h"
const char *reserved_field_names[] = {
"common_type",
"common_flags",
"common_preempt_count",
"common_pid",
"common_tgid",
FIELD_STRING_IP,
FIELD_STRING_RETIP,
FIELD_STRING_FUNC,
};
/* Printing in basic type function template */
#define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt) \
int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s, const char *name, \
void *data, void *ent) \
{ \
trace_seq_printf(s, " %s=" fmt, name, *(type *)data); \
return !trace_seq_has_overflowed(s); \
} \
const char PRINT_TYPE_FMT_NAME(type)[] = fmt; \
NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(type));
DEFINE_BASIC_PRINT_TYPE_FUNC(u8 , "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "0x%Lx")
DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%Ld")
/* Print type function for string type */
int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
void *data, void *ent)
{
int len = *(u32 *)data >> 16;
if (!len)
trace_seq_printf(s, " %s=(fault)", name);
else
trace_seq_printf(s, " %s=\"%s\"", name,
(const char *)get_loc_data(data, ent));
return !trace_seq_has_overflowed(s);
}
NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
#define CHECK_FETCH_FUNCS(method, fn) \
(((FETCH_FUNC_NAME(method, u8) == fn) || \
(FETCH_FUNC_NAME(method, u16) == fn) || \
(FETCH_FUNC_NAME(method, u32) == fn) || \
(FETCH_FUNC_NAME(method, u64) == fn) || \
(FETCH_FUNC_NAME(method, string) == fn) || \
(FETCH_FUNC_NAME(method, string_size) == fn)) \
&& (fn != NULL))
/* Data fetch function templates */
#define DEFINE_FETCH_reg(type) \
void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
{ \
*(type *)dest = (type)regs_get_register(regs, \
(unsigned int)((unsigned long)offset)); \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
DEFINE_BASIC_FETCH_FUNCS(reg)
/* No string on the register */
#define fetch_reg_string NULL
#define fetch_reg_string_size NULL
#define DEFINE_FETCH_retval(type) \
void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \
void *dummy, void *dest) \
{ \
*(type *)dest = (type)regs_return_value(regs); \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
DEFINE_BASIC_FETCH_FUNCS(retval)
/* No string on the retval */
#define fetch_retval_string NULL
#define fetch_retval_string_size NULL
/* Dereference memory access function */
struct deref_fetch_param {
struct fetch_param orig;
long offset;
fetch_func_t fetch;
fetch_func_t fetch_size;
};
#define DEFINE_FETCH_deref(type) \
void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \
void *data, void *dest) \
{ \
struct deref_fetch_param *dprm = data; \
unsigned long addr; \
call_fetch(&dprm->orig, regs, &addr); \
if (addr) { \
addr += dprm->offset; \
dprm->fetch(regs, (void *)addr, dest); \
} else \
*(type *)dest = 0; \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
DEFINE_BASIC_FETCH_FUNCS(deref)
DEFINE_FETCH_deref(string)
void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
void *data, void *dest)
{
struct deref_fetch_param *dprm = data;
unsigned long addr;
call_fetch(&dprm->orig, regs, &addr);
if (addr && dprm->fetch_size) {
addr += dprm->offset;
dprm->fetch_size(regs, (void *)addr, dest);
} else
*(string_size *)dest = 0;
}
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
static void update_deref_fetch_param(struct deref_fetch_param *data)
{
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
update_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
update_symbol_cache(data->orig.data);
}
NOKPROBE_SYMBOL(update_deref_fetch_param);
static void free_deref_fetch_param(struct deref_fetch_param *data)
{
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
free_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
free_symbol_cache(data->orig.data);
kfree(data);
}
NOKPROBE_SYMBOL(free_deref_fetch_param);
/* Bitfield fetch function */
struct bitfield_fetch_param {
struct fetch_param orig;
unsigned char hi_shift;
unsigned char low_shift;
};
#define DEFINE_FETCH_bitfield(type) \
void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \
void *data, void *dest) \
{ \
struct bitfield_fetch_param *bprm = data; \
type buf = 0; \
call_fetch(&bprm->orig, regs, &buf); \
if (buf) { \
buf <<= bprm->hi_shift; \
buf >>= bprm->low_shift; \
} \
*(type *)dest = buf; \
} \
NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
DEFINE_BASIC_FETCH_FUNCS(bitfield)
#define fetch_bitfield_string NULL
#define fetch_bitfield_string_size NULL
static void
update_bitfield_fetch_param(struct bitfield_fetch_param *data)
{
/*
* Don't check the bitfield itself, because this must be the
* last fetch function.
*/
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
update_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
update_symbol_cache(data->orig.data);
}
static void
free_bitfield_fetch_param(struct bitfield_fetch_param *data)
{
/*
* Don't check the bitfield itself, because this must be the
* last fetch function.
*/
if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
free_deref_fetch_param(data->orig.data);
else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
free_symbol_cache(data->orig.data);
kfree(data);
}
static const struct fetch_type *find_fetch_type(const char *type,
const struct fetch_type *ftbl)
{
int i;
if (!type)
type = DEFAULT_FETCH_TYPE_STR;
/* Special case: bitfield */
if (*type == 'b') {
unsigned long bs;
type = strchr(type, '/');
if (!type)
goto fail;
type++;
if (kstrtoul(type, 0, &bs))
goto fail;
switch (bs) {
case 8:
return find_fetch_type("u8", ftbl);
case 16:
return find_fetch_type("u16", ftbl);
case 32:
return find_fetch_type("u32", ftbl);
case 64:
return find_fetch_type("u64", ftbl);
default:
goto fail;
}
}
for (i = 0; ftbl[i].name; i++) {
if (strcmp(type, ftbl[i].name) == 0)
return &ftbl[i];
}
fail:
return NULL;
}
/* Special function : only accept unsigned long */
static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
{
*(unsigned long *)dest = kernel_stack_pointer(regs);
}
NOKPROBE_SYMBOL(fetch_kernel_stack_address);
static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
{
*(unsigned long *)dest = user_stack_pointer(regs);
}
NOKPROBE_SYMBOL(fetch_user_stack_address);
static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
fetch_func_t orig_fn,
const struct fetch_type *ftbl)
{
int i;
if (type != &ftbl[FETCH_TYPE_STRING])
return NULL; /* Only string type needs size function */
for (i = 0; i < FETCH_MTD_END; i++)
if (type->fetch[i] == orig_fn)
return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
WARN_ON(1); /* This should not happen */
return NULL;
}
/* Split symbol and offset. */
int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
{
char *tmp;
int ret;
if (!offset)
return -EINVAL;
tmp = strchr(symbol, '+');
if (tmp) {
/* skip sign because kstrtoul doesn't accept '+' */
ret = kstrtoul(tmp + 1, 0, offset);
if (ret)
return ret;
*tmp = '\0';
} else
*offset = 0;
return 0;
}
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
static int parse_probe_vars(char *arg, const struct fetch_type *t,
struct fetch_param *f, bool is_return,
bool is_kprobe)
{
int ret = 0;
unsigned long param;
if (strcmp(arg, "retval") == 0) {
if (is_return)
f->fn = t->fetch[FETCH_MTD_retval];
else
ret = -EINVAL;
} else if (strncmp(arg, "stack", 5) == 0) {
if (arg[5] == '\0') {
if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
return -EINVAL;
if (is_kprobe)
f->fn = fetch_kernel_stack_address;
else
f->fn = fetch_user_stack_address;
} else if (isdigit(arg[5])) {
ret = kstrtoul(arg + 5, 10, ¶m);
if (ret || (is_kprobe && param > PARAM_MAX_STACK))
ret = -EINVAL;
else {
f->fn = t->fetch[FETCH_MTD_stack];
f->data = (void *)param;
}
} else
ret = -EINVAL;
} else
ret = -EINVAL;
return ret;
}
/* Recursive argument parser */
static int parse_probe_arg(char *arg, const struct fetch_type *t,
struct fetch_param *f, bool is_return, bool is_kprobe,
const struct fetch_type *ftbl)
{
unsigned long param;
long offset;
char *tmp;
int ret = 0;
switch (arg[0]) {
case '$':
ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
break;
case '%': /* named register */
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
f->fn = t->fetch[FETCH_MTD_reg];
f->data = (void *)(unsigned long)ret;
ret = 0;
}
break;
case '@': /* memory, file-offset or symbol */
if (isdigit(arg[1])) {
ret = kstrtoul(arg + 1, 0, ¶m);
if (ret)
break;
f->fn = t->fetch[FETCH_MTD_memory];
f->data = (void *)param;
} else if (arg[1] == '+') {
/* kprobes don't support file offsets */
if (is_kprobe)
return -EINVAL;
ret = kstrtol(arg + 2, 0, &offset);
if (ret)
break;
f->fn = t->fetch[FETCH_MTD_file_offset];
f->data = (void *)offset;
} else {
/* uprobes don't support symbols */
if (!is_kprobe)
return -EINVAL;
ret = traceprobe_split_symbol_offset(arg + 1, &offset);
if (ret)
break;
f->data = alloc_symbol_cache(arg + 1, offset);
if (f->data)
f->fn = t->fetch[FETCH_MTD_symbol];
}
break;
case '+': /* deref memory */
arg++; /* Skip '+', because kstrtol() rejects it. */
case '-':
tmp = strchr(arg, '(');
if (!tmp)
break;
*tmp = '\0';
ret = kstrtol(arg, 0, &offset);
if (ret)
break;
arg = tmp + 1;
tmp = strrchr(arg, ')');
if (tmp) {
struct deref_fetch_param *dprm;
const struct fetch_type *t2;
t2 = find_fetch_type(NULL, ftbl);
*tmp = '\0';
dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
if (!dprm)
return -ENOMEM;
dprm->offset = offset;
dprm->fetch = t->fetch[FETCH_MTD_memory];
dprm->fetch_size = get_fetch_size_function(t,
dprm->fetch, ftbl);
ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
is_kprobe, ftbl);
if (ret)
kfree(dprm);
else {
f->fn = t->fetch[FETCH_MTD_deref];
f->data = (void *)dprm;
}
}
break;
}
if (!ret && !f->fn) { /* Parsed, but do not find fetch method */
pr_info("%s type has no corresponding fetch method.\n", t->name);
ret = -EINVAL;
}
return ret;
}
#define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long))
/* Bitfield type needs to be parsed into a fetch function */
static int __parse_bitfield_probe_arg(const char *bf,
const struct fetch_type *t,
struct fetch_param *f)
{
struct bitfield_fetch_param *bprm;
unsigned long bw, bo;
char *tail;
if (*bf != 'b')
return 0;
bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
if (!bprm)
return -ENOMEM;
bprm->orig = *f;
f->fn = t->fetch[FETCH_MTD_bitfield];
f->data = (void *)bprm;
bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */
if (bw == 0 || *tail != '@')
return -EINVAL;
bf = tail + 1;
bo = simple_strtoul(bf, &tail, 0);
if (tail == bf || *tail != '/')
return -EINVAL;
bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
bprm->low_shift = bprm->hi_shift + bo;
return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
}
/* String length checking wrapper */
int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
struct probe_arg *parg, bool is_return, bool is_kprobe,
const struct fetch_type *ftbl)
{
const char *t;
int ret;
if (strlen(arg) > MAX_ARGSTR_LEN) {
pr_info("Argument is too long.: %s\n", arg);
return -ENOSPC;
}
parg->comm = kstrdup(arg, GFP_KERNEL);
if (!parg->comm) {
pr_info("Failed to allocate memory for command '%s'.\n", arg);
return -ENOMEM;
}
t = strchr(parg->comm, ':');
if (t) {
arg[t - parg->comm] = '\0';
t++;
}
parg->type = find_fetch_type(t, ftbl);
if (!parg->type) {
pr_info("Unsupported type: %s\n", t);
return -EINVAL;
}
parg->offset = *size;
*size += parg->type->size;
ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
is_kprobe, ftbl);
if (ret >= 0 && t != NULL)
ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
if (ret >= 0) {
parg->fetch_size.fn = get_fetch_size_function(parg->type,
parg->fetch.fn,
ftbl);
parg->fetch_size.data = parg->fetch.data;
}
return ret;
}
/* Return 1 if name is reserved or already used by another argument */
int traceprobe_conflict_field_name(const char *name,
struct probe_arg *args, int narg)
{
int i;
for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
if (strcmp(reserved_field_names[i], name) == 0)
return 1;
for (i = 0; i < narg; i++)
if (strcmp(args[i].name, name) == 0)
return 1;
return 0;
}
void traceprobe_update_arg(struct probe_arg *arg)
{
if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
update_bitfield_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
update_deref_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
update_symbol_cache(arg->fetch.data);
}
void traceprobe_free_probe_arg(struct probe_arg *arg)
{
if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
free_bitfield_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
free_deref_fetch_param(arg->fetch.data);
else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
free_symbol_cache(arg->fetch.data);
kfree(arg->name);
kfree(arg->comm);
}
int traceprobe_command(const char *buf, int (*createfn)(int, char **))
{
char **argv;
int argc, ret;
argc = 0;
ret = 0;
argv = argv_split(GFP_KERNEL, buf, &argc);
if (!argv)
return -ENOMEM;
if (argc)
ret = createfn(argc, argv);
argv_free(argv);
return ret;
}
#define WRITE_BUFSIZE 4096
ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos,
int (*createfn)(int, char **))
{
char *kbuf, *tmp;
int ret = 0;
size_t done = 0;
size_t size;
kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
while (done < count) {
size = count - done;
if (size >= WRITE_BUFSIZE)
size = WRITE_BUFSIZE - 1;
if (copy_from_user(kbuf, buffer + done, size)) {
ret = -EFAULT;
goto out;
}
kbuf[size] = '\0';
tmp = strchr(kbuf, '\n');
if (tmp) {
*tmp = '\0';
size = tmp - kbuf + 1;
} else if (done + size < count) {
pr_warning("Line length is too long: "
"Should be less than %d.", WRITE_BUFSIZE);
ret = -EINVAL;
goto out;
}
done += size;
/* Remove comments */
tmp = strchr(kbuf, '#');
if (tmp)
*tmp = '\0';
ret = traceprobe_command(kbuf, createfn);
if (ret)
goto out;
}
ret = done;
out:
kfree(kbuf);
return ret;
}
static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
bool is_return)
{
int i;
int pos = 0;
const char *fmt, *arg;
if (!is_return) {
fmt = "(%lx)";
arg = "REC->" FIELD_STRING_IP;
} else {
fmt = "(%lx <- %lx)";
arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
}
/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
for (i = 0; i < tp->nr_args; i++) {
pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
tp->args[i].name, tp->args[i].type->fmt);
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
for (i = 0; i < tp->nr_args; i++) {
if (strcmp(tp->args[i].type->name, "string") == 0)
pos += snprintf(buf + pos, LEN_OR_ZERO,
", __get_str(%s)",
tp->args[i].name);
else
pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
tp->args[i].name);
}
#undef LEN_OR_ZERO
/* return the length of print_fmt */
return pos;
}
int set_print_fmt(struct trace_probe *tp, bool is_return)
{
int len;
char *print_fmt;
/* First: called with 0 length to calculate the needed length */
len = __set_print_fmt(tp, NULL, 0, is_return);
print_fmt = kmalloc(len + 1, GFP_KERNEL);
if (!print_fmt)
return -ENOMEM;
/* Second: actually write the @print_fmt */
__set_print_fmt(tp, print_fmt, len + 1, is_return);
tp->call.print_fmt = print_fmt;
return 0;
}