linux/kernel/trace/trace_probe.c
Masami Hiramatsu (Google) 25f00e40ce tracing/probes: Support $argN in return probe (kprobe and fprobe)
Support accessing $argN in the return probe events. This will help users to
record entry data in function return (exit) event for simplfing the function
entry/exit information in one event, and record the result values (e.g.
allocated object/initialized object) at function exit.

For example, if we have a function `int init_foo(struct foo *obj, int param)`
sometimes we want to check how `obj` is initialized. In such case, we can
define a new return event like below;

 # echo 'r init_foo retval=$retval param=$arg2 field1=+0($arg1)' >> kprobe_events

Thus it records the function parameter `param` and its result `obj->field1`
(the dereference will be done in the function exit timing) value at once.

This also support fprobe, BTF args and'$arg*'. So if CONFIG_DEBUG_INFO_BTF
is enabled, we can trace both function parameters and the return value
by following command.

 # echo 'f target_function%return $arg* $retval' >> dynamic_events

Link: https://lore.kernel.org/all/170952365552.229804.224112990211602895.stgit@devnote2/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2024-03-07 00:27:34 +09:00

2166 lines
50 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Common code for probe-based Dynamic events.
*
* 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
*/
#define pr_fmt(fmt) "trace_probe: " fmt
#include <linux/bpf.h>
#include "trace_btf.h"
#include "trace_probe.h"
#undef C
#define C(a, b) b
static const char *trace_probe_err_text[] = { ERRORS };
static 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(tname, type, fmt) \
int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
{ \
trace_seq_printf(s, fmt, *(type *)data); \
return !trace_seq_has_overflowed(s); \
} \
const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u")
DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'")
int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
{
trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
return !trace_seq_has_overflowed(s);
}
const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
/* Print type function for string type */
int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
{
int len = *(u32 *)data >> 16;
if (!len)
trace_seq_puts(s, FAULT_STRING);
else
trace_seq_printf(s, "\"%s\"",
(const char *)get_loc_data(data, ent));
return !trace_seq_has_overflowed(s);
}
const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
/* Fetch type information table */
static const struct fetch_type probe_fetch_types[] = {
/* Special types */
__ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1,
"__data_loc char[]"),
__ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1,
"__data_loc char[]"),
__ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1,
"__data_loc char[]"),
/* 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_ALIAS(char, u8, u8, 0),
ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
ASSIGN_FETCH_TYPE_END
};
static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags)
{
int i;
/* Reject the symbol/symstr for uprobes */
if (type && (flags & TPARG_FL_USER) &&
(!strcmp(type, "symbol") || !strcmp(type, "symstr")))
return NULL;
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", flags);
case 16:
return find_fetch_type("u16", flags);
case 32:
return find_fetch_type("u32", flags);
case 64:
return find_fetch_type("u64", flags);
default:
goto fail;
}
}
for (i = 0; probe_fetch_types[i].name; i++) {
if (strcmp(type, probe_fetch_types[i].name) == 0)
return &probe_fetch_types[i];
}
fail:
return NULL;
}
static struct trace_probe_log trace_probe_log;
void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
{
trace_probe_log.subsystem = subsystem;
trace_probe_log.argc = argc;
trace_probe_log.argv = argv;
trace_probe_log.index = 0;
}
void trace_probe_log_clear(void)
{
memset(&trace_probe_log, 0, sizeof(trace_probe_log));
}
void trace_probe_log_set_index(int index)
{
trace_probe_log.index = index;
}
void __trace_probe_log_err(int offset, int err_type)
{
char *command, *p;
int i, len = 0, pos = 0;
if (!trace_probe_log.argv)
return;
/* Recalculate the length and allocate buffer */
for (i = 0; i < trace_probe_log.argc; i++) {
if (i == trace_probe_log.index)
pos = len;
len += strlen(trace_probe_log.argv[i]) + 1;
}
command = kzalloc(len, GFP_KERNEL);
if (!command)
return;
if (trace_probe_log.index >= trace_probe_log.argc) {
/**
* Set the error position is next to the last arg + space.
* Note that len includes the terminal null and the cursor
* appears at pos + 1.
*/
pos = len;
offset = 0;
}
/* And make a command string from argv array */
p = command;
for (i = 0; i < trace_probe_log.argc; i++) {
len = strlen(trace_probe_log.argv[i]);
strcpy(p, trace_probe_log.argv[i]);
p[len] = ' ';
p += len + 1;
}
*(p - 1) = '\0';
tracing_log_err(NULL, trace_probe_log.subsystem, command,
trace_probe_err_text, err_type, pos + offset);
kfree(command);
}
/* Split symbol and offset. */
int traceprobe_split_symbol_offset(char *symbol, long *offset)
{
char *tmp;
int ret;
if (!offset)
return -EINVAL;
tmp = strpbrk(symbol, "+-");
if (tmp) {
ret = kstrtol(tmp, 0, offset);
if (ret)
return ret;
*tmp = '\0';
} else
*offset = 0;
return 0;
}
/* @buf must has MAX_EVENT_NAME_LEN size */
int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
char *buf, int offset)
{
const char *slash, *event = *pevent;
int len;
slash = strchr(event, '/');
if (!slash)
slash = strchr(event, '.');
if (slash) {
if (slash == event) {
trace_probe_log_err(offset, NO_GROUP_NAME);
return -EINVAL;
}
if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
trace_probe_log_err(offset, GROUP_TOO_LONG);
return -EINVAL;
}
strscpy(buf, event, slash - event + 1);
if (!is_good_system_name(buf)) {
trace_probe_log_err(offset, BAD_GROUP_NAME);
return -EINVAL;
}
*pgroup = buf;
*pevent = slash + 1;
offset += slash - event + 1;
event = *pevent;
}
len = strlen(event);
if (len == 0) {
if (slash) {
*pevent = NULL;
return 0;
}
trace_probe_log_err(offset, NO_EVENT_NAME);
return -EINVAL;
} else if (len > MAX_EVENT_NAME_LEN) {
trace_probe_log_err(offset, EVENT_TOO_LONG);
return -EINVAL;
}
if (!is_good_name(event)) {
trace_probe_log_err(offset, BAD_EVENT_NAME);
return -EINVAL;
}
return 0;
}
static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
struct traceprobe_parse_context *ctx)
{
struct ftrace_event_field *field;
struct list_head *head;
head = trace_get_fields(ctx->event);
list_for_each_entry(field, head, link) {
if (!strcmp(arg, field->name)) {
code->op = FETCH_OP_TP_ARG;
code->data = field;
return 0;
}
}
return -ENOENT;
}
#ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
static u32 btf_type_int(const struct btf_type *t)
{
return *(u32 *)(t + 1);
}
static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type)
{
const struct btf_type *real_type;
u32 intdata;
s32 tid;
real_type = btf_type_skip_modifiers(btf, type->type, &tid);
if (!real_type)
return false;
if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT)
return false;
intdata = btf_type_int(real_type);
return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
&& BTF_INT_BITS(intdata) == 8;
}
static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
{
const struct btf_type *real_type;
const struct btf_array *array;
u32 intdata;
s32 tid;
if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY)
return false;
array = (const struct btf_array *)(type + 1);
real_type = btf_type_skip_modifiers(btf, array->type, &tid);
intdata = btf_type_int(real_type);
return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED)
&& BTF_INT_BITS(intdata) == 8;
}
static int check_prepare_btf_string_fetch(char *typename,
struct fetch_insn **pcode,
struct traceprobe_parse_context *ctx)
{
struct btf *btf = ctx->btf;
if (!btf || !ctx->last_type)
return 0;
/* char [] does not need any change. */
if (btf_type_is_char_array(btf, ctx->last_type))
return 0;
/* char * requires dereference the pointer. */
if (btf_type_is_char_ptr(btf, ctx->last_type)) {
struct fetch_insn *code = *pcode + 1;
if (code->op == FETCH_OP_END) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -E2BIG;
}
if (typename[0] == 'u')
code->op = FETCH_OP_UDEREF;
else
code->op = FETCH_OP_DEREF;
code->offset = 0;
*pcode = code;
return 0;
}
/* Other types are not available for string */
trace_probe_log_err(ctx->offset, BAD_TYPE4STR);
return -EINVAL;
}
static const char *fetch_type_from_btf_type(struct btf *btf,
const struct btf_type *type,
struct traceprobe_parse_context *ctx)
{
u32 intdata;
/* TODO: const char * could be converted as a string */
switch (BTF_INFO_KIND(type->info)) {
case BTF_KIND_ENUM:
/* enum is "int", so convert to "s32" */
return "s32";
case BTF_KIND_ENUM64:
return "s64";
case BTF_KIND_PTR:
/* pointer will be converted to "x??" */
if (IS_ENABLED(CONFIG_64BIT))
return "x64";
else
return "x32";
case BTF_KIND_INT:
intdata = btf_type_int(type);
if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) {
switch (BTF_INT_BITS(intdata)) {
case 8:
return "s8";
case 16:
return "s16";
case 32:
return "s32";
case 64:
return "s64";
}
} else { /* unsigned */
switch (BTF_INT_BITS(intdata)) {
case 8:
return "u8";
case 16:
return "u16";
case 32:
return "u32";
case 64:
return "u64";
}
/* bitfield, size is encoded in the type */
ctx->last_bitsize = BTF_INT_BITS(intdata);
ctx->last_bitoffs += BTF_INT_OFFSET(intdata);
return "u64";
}
}
/* TODO: support other types */
return NULL;
}
static int query_btf_context(struct traceprobe_parse_context *ctx)
{
const struct btf_param *param;
const struct btf_type *type;
struct btf *btf;
s32 nr;
if (ctx->btf)
return 0;
if (!ctx->funcname)
return -EINVAL;
type = btf_find_func_proto(ctx->funcname, &btf);
if (!type)
return -ENOENT;
ctx->btf = btf;
ctx->proto = type;
/* ctx->params is optional, since func(void) will not have params. */
nr = 0;
param = btf_get_func_param(type, &nr);
if (!IS_ERR_OR_NULL(param)) {
/* Hide the first 'data' argument of tracepoint */
if (ctx->flags & TPARG_FL_TPOINT) {
nr--;
param++;
}
}
if (nr > 0) {
ctx->nr_params = nr;
ctx->params = param;
} else {
ctx->nr_params = 0;
ctx->params = NULL;
}
return 0;
}
static void clear_btf_context(struct traceprobe_parse_context *ctx)
{
if (ctx->btf) {
btf_put(ctx->btf);
ctx->btf = NULL;
ctx->proto = NULL;
ctx->params = NULL;
ctx->nr_params = 0;
}
}
/* Return 1 if the field separater is arrow operator ('->') */
static int split_next_field(char *varname, char **next_field,
struct traceprobe_parse_context *ctx)
{
char *field;
int ret = 0;
field = strpbrk(varname, ".-");
if (field) {
if (field[0] == '-' && field[1] == '>') {
field[0] = '\0';
field += 2;
ret = 1;
} else if (field[0] == '.') {
field[0] = '\0';
field += 1;
} else {
trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN);
return -EINVAL;
}
*next_field = field;
}
return ret;
}
/*
* Parse the field of data structure. The @type must be a pointer type
* pointing the target data structure type.
*/
static int parse_btf_field(char *fieldname, const struct btf_type *type,
struct fetch_insn **pcode, struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
const struct btf_member *field;
u32 bitoffs, anon_offs;
char *next;
int is_ptr;
s32 tid;
do {
/* Outer loop for solving arrow operator ('->') */
if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
return -EINVAL;
}
/* Convert a struct pointer type to a struct type */
type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
if (!type) {
trace_probe_log_err(ctx->offset, BAD_BTF_TID);
return -EINVAL;
}
bitoffs = 0;
do {
/* Inner loop for solving dot operator ('.') */
next = NULL;
is_ptr = split_next_field(fieldname, &next, ctx);
if (is_ptr < 0)
return is_ptr;
anon_offs = 0;
field = btf_find_struct_member(ctx->btf, type, fieldname,
&anon_offs);
if (!field) {
trace_probe_log_err(ctx->offset, NO_BTF_FIELD);
return -ENOENT;
}
/* Add anonymous structure/union offset */
bitoffs += anon_offs;
/* Accumulate the bit-offsets of the dot-connected fields */
if (btf_type_kflag(type)) {
bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset);
ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset);
} else {
bitoffs += field->offset;
ctx->last_bitsize = 0;
}
type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
if (!type) {
trace_probe_log_err(ctx->offset, BAD_BTF_TID);
return -EINVAL;
}
ctx->offset += next - fieldname;
fieldname = next;
} while (!is_ptr && fieldname);
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
code->op = FETCH_OP_DEREF; /* TODO: user deref support */
code->offset = bitoffs / 8;
*pcode = code;
ctx->last_bitoffs = bitoffs % 8;
ctx->last_type = type;
} while (fieldname);
return 0;
}
static int __store_entry_arg(struct trace_probe *tp, int argnum);
static int parse_btf_arg(char *varname,
struct fetch_insn **pcode, struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
const struct btf_param *params;
const struct btf_type *type;
char *field = NULL;
int i, is_ptr, ret;
u32 tid;
if (WARN_ON_ONCE(!ctx->funcname))
return -EINVAL;
is_ptr = split_next_field(varname, &field, ctx);
if (is_ptr < 0)
return is_ptr;
if (!is_ptr && field) {
/* dot-connected field on an argument is not supported. */
trace_probe_log_err(ctx->offset + field - varname,
NOSUP_DAT_ARG);
return -EOPNOTSUPP;
}
if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
code->op = FETCH_OP_RETVAL;
/* Check whether the function return type is not void */
if (query_btf_context(ctx) == 0) {
if (ctx->proto->type == 0) {
trace_probe_log_err(ctx->offset, NO_RETVAL);
return -ENOENT;
}
tid = ctx->proto->type;
goto found;
}
if (field) {
trace_probe_log_err(ctx->offset + field - varname,
NO_BTF_ENTRY);
return -ENOENT;
}
return 0;
}
if (!ctx->btf) {
ret = query_btf_context(ctx);
if (ret < 0 || ctx->nr_params == 0) {
trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
return PTR_ERR(params);
}
}
params = ctx->params;
for (i = 0; i < ctx->nr_params; i++) {
const char *name = btf_name_by_offset(ctx->btf, params[i].name_off);
if (name && !strcmp(name, varname)) {
if (tparg_is_function_entry(ctx->flags)) {
code->op = FETCH_OP_ARG;
if (ctx->flags & TPARG_FL_TPOINT)
code->param = i + 1;
else
code->param = i;
} else if (tparg_is_function_return(ctx->flags)) {
code->op = FETCH_OP_EDATA;
ret = __store_entry_arg(ctx->tp, i);
if (ret < 0) {
/* internal error */
return ret;
}
code->offset = ret;
}
tid = params[i].type;
goto found;
}
}
trace_probe_log_err(ctx->offset, NO_BTFARG);
return -ENOENT;
found:
type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
if (!type) {
trace_probe_log_err(ctx->offset, BAD_BTF_TID);
return -EINVAL;
}
/* Initialize the last type information */
ctx->last_type = type;
ctx->last_bitoffs = 0;
ctx->last_bitsize = 0;
if (field) {
ctx->offset += field - varname;
return parse_btf_field(field, type, pcode, end, ctx);
}
return 0;
}
static const struct fetch_type *find_fetch_type_from_btf_type(
struct traceprobe_parse_context *ctx)
{
struct btf *btf = ctx->btf;
const char *typestr = NULL;
if (btf && ctx->last_type)
typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx);
return find_fetch_type(typestr, ctx->flags);
}
static int parse_btf_bitfield(struct fetch_insn **pcode,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0)
return 0;
code++;
if (code->op != FETCH_OP_NOP) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
*pcode = code;
code->op = FETCH_OP_MOD_BF;
code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs);
code->rshift = 64 - ctx->last_bitsize;
code->basesize = 64 / 8;
return 0;
}
#else
static void clear_btf_context(struct traceprobe_parse_context *ctx)
{
ctx->btf = NULL;
}
static int query_btf_context(struct traceprobe_parse_context *ctx)
{
return -EOPNOTSUPP;
}
static int parse_btf_arg(char *varname,
struct fetch_insn **pcode, struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EOPNOTSUPP;
}
static int parse_btf_bitfield(struct fetch_insn **pcode,
struct traceprobe_parse_context *ctx)
{
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EOPNOTSUPP;
}
#define find_fetch_type_from_btf_type(ctx) \
find_fetch_type(NULL, ctx->flags)
static int check_prepare_btf_string_fetch(char *typename,
struct fetch_insn **pcode,
struct traceprobe_parse_context *ctx)
{
return 0;
}
#endif
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
static int __store_entry_arg(struct trace_probe *tp, int argnum)
{
struct probe_entry_arg *earg = tp->entry_arg;
bool match = false;
int i, offset;
if (!earg) {
earg = kzalloc(sizeof(*tp->entry_arg), GFP_KERNEL);
if (!earg)
return -ENOMEM;
earg->size = 2 * tp->nr_args + 1;
earg->code = kcalloc(earg->size, sizeof(struct fetch_insn),
GFP_KERNEL);
if (!earg->code) {
kfree(earg);
return -ENOMEM;
}
/* Fill the code buffer with 'end' to simplify it */
for (i = 0; i < earg->size; i++)
earg->code[i].op = FETCH_OP_END;
tp->entry_arg = earg;
}
offset = 0;
for (i = 0; i < earg->size - 1; i++) {
switch (earg->code[i].op) {
case FETCH_OP_END:
earg->code[i].op = FETCH_OP_ARG;
earg->code[i].param = argnum;
earg->code[i + 1].op = FETCH_OP_ST_EDATA;
earg->code[i + 1].offset = offset;
return offset;
case FETCH_OP_ARG:
match = (earg->code[i].param == argnum);
break;
case FETCH_OP_ST_EDATA:
offset = earg->code[i].offset;
if (match)
return offset;
offset += sizeof(unsigned long);
break;
default:
break;
}
}
return -ENOSPC;
}
int traceprobe_get_entry_data_size(struct trace_probe *tp)
{
struct probe_entry_arg *earg = tp->entry_arg;
int i, size = 0;
if (!earg)
return 0;
for (i = 0; i < earg->size; i++) {
switch (earg->code[i].op) {
case FETCH_OP_END:
goto out;
case FETCH_OP_ST_EDATA:
size = earg->code[i].offset + sizeof(unsigned long);
break;
default:
break;
}
}
out:
return size;
}
void store_trace_entry_data(void *edata, struct trace_probe *tp, struct pt_regs *regs)
{
struct probe_entry_arg *earg = tp->entry_arg;
unsigned long val;
int i;
if (!earg)
return;
for (i = 0; i < earg->size; i++) {
struct fetch_insn *code = &earg->code[i];
switch (code->op) {
case FETCH_OP_ARG:
val = regs_get_kernel_argument(regs, code->param);
break;
case FETCH_OP_ST_EDATA:
*(unsigned long *)((unsigned long)edata + code->offset) = val;
break;
case FETCH_OP_END:
goto end;
default:
break;
}
}
end:
return;
}
NOKPROBE_SYMBOL(store_trace_entry_data)
#endif
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
/* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */
static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
struct fetch_insn **pcode,
struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
int err = TP_ERR_BAD_VAR;
char *arg = orig_arg + 1;
unsigned long param;
int ret = 0;
int len;
if (ctx->flags & TPARG_FL_TEVENT) {
if (code->data)
return -EFAULT;
ret = parse_trace_event_arg(arg, code, ctx);
if (!ret)
return 0;
if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
code->op = FETCH_OP_COMM;
return 0;
}
/* backward compatibility */
ctx->offset = 0;
goto inval;
}
if (str_has_prefix(arg, "retval")) {
if (!(ctx->flags & TPARG_FL_RETURN)) {
err = TP_ERR_RETVAL_ON_PROBE;
goto inval;
}
if (!(ctx->flags & TPARG_FL_KERNEL) ||
!IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
code->op = FETCH_OP_RETVAL;
return 0;
}
return parse_btf_arg(orig_arg, pcode, end, ctx);
}
len = str_has_prefix(arg, "stack");
if (len) {
if (arg[len] == '\0') {
code->op = FETCH_OP_STACKP;
return 0;
}
if (isdigit(arg[len])) {
ret = kstrtoul(arg + len, 10, &param);
if (ret)
goto inval;
if ((ctx->flags & TPARG_FL_KERNEL) &&
param > PARAM_MAX_STACK) {
err = TP_ERR_BAD_STACK_NUM;
goto inval;
}
code->op = FETCH_OP_STACK;
code->param = (unsigned int)param;
return 0;
}
goto inval;
}
if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
code->op = FETCH_OP_COMM;
return 0;
}
#ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
len = str_has_prefix(arg, "arg");
if (len) {
ret = kstrtoul(arg + len, 10, &param);
if (ret)
goto inval;
if (!param || param > PARAM_MAX_STACK) {
err = TP_ERR_BAD_ARG_NUM;
goto inval;
}
param--; /* argN starts from 1, but internal arg[N] starts from 0 */
if (tparg_is_function_entry(ctx->flags)) {
code->op = FETCH_OP_ARG;
code->param = (unsigned int)param;
/*
* The tracepoint probe will probe a stub function, and the
* first parameter of the stub is a dummy and should be ignored.
*/
if (ctx->flags & TPARG_FL_TPOINT)
code->param++;
} else if (tparg_is_function_return(ctx->flags)) {
/* function entry argument access from return probe */
ret = __store_entry_arg(ctx->tp, param);
if (ret < 0) /* This error should be an internal error */
return ret;
code->op = FETCH_OP_EDATA;
code->offset = ret;
} else {
err = TP_ERR_NOFENTRY_ARGS;
goto inval;
}
return 0;
}
#endif
inval:
__trace_probe_log_err(ctx->offset, err);
return -EINVAL;
}
static int str_to_immediate(char *str, unsigned long *imm)
{
if (isdigit(str[0]))
return kstrtoul(str, 0, imm);
else if (str[0] == '-')
return kstrtol(str, 0, (long *)imm);
else if (str[0] == '+')
return kstrtol(str + 1, 0, (long *)imm);
return -EINVAL;
}
static int __parse_imm_string(char *str, char **pbuf, int offs)
{
size_t len = strlen(str);
if (str[len - 1] != '"') {
trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
return -EINVAL;
}
*pbuf = kstrndup(str, len - 1, GFP_KERNEL);
if (!*pbuf)
return -ENOMEM;
return 0;
}
/* Recursive argument parser */
static int
parse_probe_arg(char *arg, const struct fetch_type *type,
struct fetch_insn **pcode, struct fetch_insn *end,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code = *pcode;
unsigned long param;
int deref = FETCH_OP_DEREF;
long offset = 0;
char *tmp;
int ret = 0;
switch (arg[0]) {
case '$':
ret = parse_probe_vars(arg, type, pcode, end, ctx);
break;
case '%': /* named register */
if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) {
/* eprobe and fprobe do not handle registers */
trace_probe_log_err(ctx->offset, BAD_VAR);
break;
}
ret = regs_query_register_offset(arg + 1);
if (ret >= 0) {
code->op = FETCH_OP_REG;
code->param = (unsigned int)ret;
ret = 0;
} else
trace_probe_log_err(ctx->offset, BAD_REG_NAME);
break;
case '@': /* memory, file-offset or symbol */
if (isdigit(arg[1])) {
ret = kstrtoul(arg + 1, 0, &param);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_MEM_ADDR);
break;
}
/* load address */
code->op = FETCH_OP_IMM;
code->immediate = param;
} else if (arg[1] == '+') {
/* kprobes don't support file offsets */
if (ctx->flags & TPARG_FL_KERNEL) {
trace_probe_log_err(ctx->offset, FILE_ON_KPROBE);
return -EINVAL;
}
ret = kstrtol(arg + 2, 0, &offset);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_FILE_OFFS);
break;
}
code->op = FETCH_OP_FOFFS;
code->immediate = (unsigned long)offset; // imm64?
} else {
/* uprobes don't support symbols */
if (!(ctx->flags & TPARG_FL_KERNEL)) {
trace_probe_log_err(ctx->offset, SYM_ON_UPROBE);
return -EINVAL;
}
/* Preserve symbol for updating */
code->op = FETCH_NOP_SYMBOL;
code->data = kstrdup(arg + 1, GFP_KERNEL);
if (!code->data)
return -ENOMEM;
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
code->op = FETCH_OP_IMM;
code->immediate = 0;
}
/* These are fetching from memory */
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
*pcode = code;
code->op = FETCH_OP_DEREF;
code->offset = offset;
break;
case '+': /* deref memory */
case '-':
if (arg[1] == 'u') {
deref = FETCH_OP_UDEREF;
arg[1] = arg[0];
arg++;
}
if (arg[0] == '+')
arg++; /* Skip '+', because kstrtol() rejects it. */
tmp = strchr(arg, '(');
if (!tmp) {
trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE);
return -EINVAL;
}
*tmp = '\0';
ret = kstrtol(arg, 0, &offset);
if (ret) {
trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS);
break;
}
ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
arg = tmp + 1;
tmp = strrchr(arg, ')');
if (!tmp) {
trace_probe_log_err(ctx->offset + strlen(arg),
DEREF_OPEN_BRACE);
return -EINVAL;
} else {
const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags);
int cur_offs = ctx->offset;
*tmp = '\0';
ret = parse_probe_arg(arg, t2, &code, end, ctx);
if (ret)
break;
ctx->offset = cur_offs;
if (code->op == FETCH_OP_COMM ||
code->op == FETCH_OP_DATA) {
trace_probe_log_err(ctx->offset, COMM_CANT_DEREF);
return -EINVAL;
}
if (++code == end) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
*pcode = code;
code->op = deref;
code->offset = offset;
/* Reset the last type if used */
ctx->last_type = NULL;
}
break;
case '\\': /* Immediate value */
if (arg[1] == '"') { /* Immediate string */
ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2);
if (ret)
break;
code->op = FETCH_OP_DATA;
code->data = tmp;
} else {
ret = str_to_immediate(arg + 1, &code->immediate);
if (ret)
trace_probe_log_err(ctx->offset + 1, BAD_IMM);
else
code->op = FETCH_OP_IMM;
}
break;
default:
if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
if (!tparg_is_function_entry(ctx->flags) &&
!tparg_is_function_return(ctx->flags)) {
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EINVAL;
}
ret = parse_btf_arg(arg, pcode, end, ctx);
break;
}
}
if (!ret && code->op == FETCH_OP_NOP) {
/* Parsed, but do not find fetch method */
trace_probe_log_err(ctx->offset, BAD_FETCH_ARG);
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_insn **pcode)
{
struct fetch_insn *code = *pcode;
unsigned long bw, bo;
char *tail;
if (*bf != 'b')
return 0;
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;
code++;
if (code->op != FETCH_OP_NOP)
return -EINVAL;
*pcode = code;
code->op = FETCH_OP_MOD_BF;
code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
code->rshift = BYTES_TO_BITS(t->size) - bw;
code->basesize = t->size;
return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
}
/* Split type part from @arg and return it. */
static char *parse_probe_arg_type(char *arg, struct probe_arg *parg,
struct traceprobe_parse_context *ctx)
{
char *t = NULL, *t2, *t3;
int offs;
t = strchr(arg, ':');
if (t) {
*t++ = '\0';
t2 = strchr(t, '[');
if (t2) {
*t2++ = '\0';
t3 = strchr(t2, ']');
if (!t3) {
offs = t2 + strlen(t2) - arg;
trace_probe_log_err(ctx->offset + offs,
ARRAY_NO_CLOSE);
return ERR_PTR(-EINVAL);
} else if (t3[1] != '\0') {
trace_probe_log_err(ctx->offset + t3 + 1 - arg,
BAD_ARRAY_SUFFIX);
return ERR_PTR(-EINVAL);
}
*t3 = '\0';
if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
trace_probe_log_err(ctx->offset + t2 - arg,
BAD_ARRAY_NUM);
return ERR_PTR(-EINVAL);
}
if (parg->count > MAX_ARRAY_LEN) {
trace_probe_log_err(ctx->offset + t2 - arg,
ARRAY_TOO_BIG);
return ERR_PTR(-EINVAL);
}
}
}
offs = t ? t - arg : 0;
/*
* Since $comm and immediate string can not be dereferenced,
* we can find those by strcmp. But ignore for eprobes.
*/
if (!(ctx->flags & TPARG_FL_TEVENT) &&
(strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
strncmp(arg, "\\\"", 2) == 0)) {
/* The type of $comm must be "string", and not an array type. */
if (parg->count || (t && strcmp(t, "string"))) {
trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE);
return ERR_PTR(-EINVAL);
}
parg->type = find_fetch_type("string", ctx->flags);
} else
parg->type = find_fetch_type(t, ctx->flags);
if (!parg->type) {
trace_probe_log_err(ctx->offset + offs, BAD_TYPE);
return ERR_PTR(-EINVAL);
}
return t;
}
/* After parsing, adjust the fetch_insn according to the probe_arg */
static int finalize_fetch_insn(struct fetch_insn *code,
struct probe_arg *parg,
char *type,
int type_offset,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *scode;
int ret;
/* Store operation */
if (parg->type->is_string) {
/* Check bad combination of the type and the last fetch_insn. */
if (!strcmp(parg->type->name, "symstr")) {
if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK &&
code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG &&
code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) {
trace_probe_log_err(ctx->offset + type_offset,
BAD_SYMSTRING);
return -EINVAL;
}
} else {
if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) {
trace_probe_log_err(ctx->offset + type_offset,
BAD_STRING);
return -EINVAL;
}
}
if (!strcmp(parg->type->name, "symstr") ||
(code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG ||
parg->count) {
/*
* IMM, DATA and COMM is pointing actual address, those
* must be kept, and if parg->count != 0, this is an
* array of string pointers instead of string address
* itself.
* For the symstr, it doesn't need to dereference, thus
* it just get the value.
*/
code++;
if (code->op != FETCH_OP_NOP) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -EINVAL;
}
}
/* If op == DEREF, replace it with STRING */
if (!strcmp(parg->type->name, "ustring") ||
code->op == FETCH_OP_UDEREF)
code->op = FETCH_OP_ST_USTRING;
else if (!strcmp(parg->type->name, "symstr"))
code->op = FETCH_OP_ST_SYMSTR;
else
code->op = FETCH_OP_ST_STRING;
code->size = parg->type->size;
parg->dynamic = true;
} else if (code->op == FETCH_OP_DEREF) {
code->op = FETCH_OP_ST_MEM;
code->size = parg->type->size;
} else if (code->op == FETCH_OP_UDEREF) {
code->op = FETCH_OP_ST_UMEM;
code->size = parg->type->size;
} else {
code++;
if (code->op != FETCH_OP_NOP) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -E2BIG;
}
code->op = FETCH_OP_ST_RAW;
code->size = parg->type->size;
}
/* Save storing fetch_insn. */
scode = code;
/* Modify operation */
if (type != NULL) {
/* Bitfield needs a special fetch_insn. */
ret = __parse_bitfield_probe_arg(type, parg->type, &code);
if (ret) {
trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD);
return ret;
}
} else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
ctx->last_type) {
/* If user not specified the type, try parsing BTF bitfield. */
ret = parse_btf_bitfield(&code, ctx);
if (ret)
return ret;
}
/* Loop(Array) operation */
if (parg->count) {
if (scode->op != FETCH_OP_ST_MEM &&
scode->op != FETCH_OP_ST_STRING &&
scode->op != FETCH_OP_ST_USTRING) {
trace_probe_log_err(ctx->offset + type_offset, BAD_STRING);
return -EINVAL;
}
code++;
if (code->op != FETCH_OP_NOP) {
trace_probe_log_err(ctx->offset, TOO_MANY_OPS);
return -E2BIG;
}
code->op = FETCH_OP_LP_ARRAY;
code->param = parg->count;
}
/* Finalize the fetch_insn array. */
code++;
code->op = FETCH_OP_END;
return 0;
}
/* String length checking wrapper */
static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
struct probe_arg *parg,
struct traceprobe_parse_context *ctx)
{
struct fetch_insn *code, *tmp = NULL;
char *type, *arg;
int ret, len;
len = strlen(argv);
if (len > MAX_ARGSTR_LEN) {
trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
return -E2BIG;
} else if (len == 0) {
trace_probe_log_err(ctx->offset, NO_ARG_BODY);
return -EINVAL;
}
arg = kstrdup(argv, GFP_KERNEL);
if (!arg)
return -ENOMEM;
parg->comm = kstrdup(arg, GFP_KERNEL);
if (!parg->comm) {
ret = -ENOMEM;
goto out;
}
type = parse_probe_arg_type(arg, parg, ctx);
if (IS_ERR(type)) {
ret = PTR_ERR(type);
goto out;
}
code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
if (!code) {
ret = -ENOMEM;
goto out;
}
code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
ctx->last_type = NULL;
ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
ctx);
if (ret < 0)
goto fail;
/* Update storing type if BTF is available */
if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) &&
ctx->last_type) {
if (!type) {
parg->type = find_fetch_type_from_btf_type(ctx);
} else if (strstr(type, "string")) {
ret = check_prepare_btf_string_fetch(type, &code, ctx);
if (ret)
goto fail;
}
}
parg->offset = *size;
*size += parg->type->size * (parg->count ?: 1);
if (parg->count) {
len = strlen(parg->type->fmttype) + 6;
parg->fmt = kmalloc(len, GFP_KERNEL);
if (!parg->fmt) {
ret = -ENOMEM;
goto out;
}
snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
parg->count);
}
ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx);
if (ret < 0)
goto fail;
for (; code < tmp + FETCH_INSN_MAX; code++)
if (code->op == FETCH_OP_END)
break;
/* Shrink down the code buffer */
parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
if (!parg->code)
ret = -ENOMEM;
else
memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
fail:
if (ret < 0) {
for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
if (code->op == FETCH_NOP_SYMBOL ||
code->op == FETCH_OP_DATA)
kfree(code->data);
}
kfree(tmp);
out:
kfree(arg);
return ret;
}
/* Return 1 if name is reserved or already used by another argument */
static 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;
}
static char *generate_probe_arg_name(const char *arg, int idx)
{
char *name = NULL;
const char *end;
/*
* If argument name is omitted, try arg as a name (BTF variable)
* or "argN".
*/
if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) {
end = strchr(arg, ':');
if (!end)
end = arg + strlen(arg);
name = kmemdup_nul(arg, end - arg, GFP_KERNEL);
if (!name || !is_good_name(name)) {
kfree(name);
name = NULL;
}
}
if (!name)
name = kasprintf(GFP_KERNEL, "arg%d", idx + 1);
return name;
}
int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
struct traceprobe_parse_context *ctx)
{
struct probe_arg *parg = &tp->args[i];
const char *body;
ctx->tp = tp;
body = strchr(arg, '=');
if (body) {
if (body - arg > MAX_ARG_NAME_LEN) {
trace_probe_log_err(0, ARG_NAME_TOO_LONG);
return -EINVAL;
} else if (body == arg) {
trace_probe_log_err(0, NO_ARG_NAME);
return -EINVAL;
}
parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
body++;
} else {
parg->name = generate_probe_arg_name(arg, i);
body = arg;
}
if (!parg->name)
return -ENOMEM;
if (!is_good_name(parg->name)) {
trace_probe_log_err(0, BAD_ARG_NAME);
return -EINVAL;
}
if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
trace_probe_log_err(0, USED_ARG_NAME);
return -EINVAL;
}
ctx->offset = body - arg;
/* Parse fetch argument */
return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx);
}
void traceprobe_free_probe_arg(struct probe_arg *arg)
{
struct fetch_insn *code = arg->code;
while (code && code->op != FETCH_OP_END) {
if (code->op == FETCH_NOP_SYMBOL ||
code->op == FETCH_OP_DATA)
kfree(code->data);
code++;
}
kfree(arg->code);
kfree(arg->name);
kfree(arg->comm);
kfree(arg->fmt);
}
static int argv_has_var_arg(int argc, const char *argv[], int *args_idx,
struct traceprobe_parse_context *ctx)
{
int i, found = 0;
for (i = 0; i < argc; i++)
if (str_has_prefix(argv[i], "$arg")) {
trace_probe_log_set_index(i + 2);
if (!tparg_is_function_entry(ctx->flags) &&
!tparg_is_function_return(ctx->flags)) {
trace_probe_log_err(0, NOFENTRY_ARGS);
return -EINVAL;
}
if (isdigit(argv[i][4])) {
found = 1;
continue;
}
if (argv[i][4] != '*') {
trace_probe_log_err(0, BAD_VAR);
return -EINVAL;
}
if (*args_idx >= 0 && *args_idx < argc) {
trace_probe_log_err(0, DOUBLE_ARGS);
return -EINVAL;
}
found = 1;
*args_idx = i;
}
return found;
}
static int sprint_nth_btf_arg(int idx, const char *type,
char *buf, int bufsize,
struct traceprobe_parse_context *ctx)
{
const char *name;
int ret;
if (idx >= ctx->nr_params) {
trace_probe_log_err(0, NO_BTFARG);
return -ENOENT;
}
name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off);
if (!name) {
trace_probe_log_err(0, NO_BTF_ENTRY);
return -ENOENT;
}
ret = snprintf(buf, bufsize, "%s%s", name, type);
if (ret >= bufsize) {
trace_probe_log_err(0, ARGS_2LONG);
return -E2BIG;
}
return ret;
}
/* Return new_argv which must be freed after use */
const char **traceprobe_expand_meta_args(int argc, const char *argv[],
int *new_argc, char *buf, int bufsize,
struct traceprobe_parse_context *ctx)
{
const struct btf_param *params = NULL;
int i, j, n, used, ret, args_idx = -1;
const char **new_argv = NULL;
ret = argv_has_var_arg(argc, argv, &args_idx, ctx);
if (ret < 0)
return ERR_PTR(ret);
if (!ret) {
*new_argc = argc;
return NULL;
}
ret = query_btf_context(ctx);
if (ret < 0 || ctx->nr_params == 0) {
if (args_idx != -1) {
/* $arg* requires BTF info */
trace_probe_log_err(0, NOSUP_BTFARG);
return (const char **)params;
}
*new_argc = argc;
return NULL;
}
if (args_idx >= 0)
*new_argc = argc + ctx->nr_params - 1;
else
*new_argc = argc;
new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL);
if (!new_argv)
return ERR_PTR(-ENOMEM);
used = 0;
for (i = 0, j = 0; i < argc; i++) {
trace_probe_log_set_index(i + 2);
if (i == args_idx) {
for (n = 0; n < ctx->nr_params; n++) {
ret = sprint_nth_btf_arg(n, "", buf + used,
bufsize - used, ctx);
if (ret < 0)
goto error;
new_argv[j++] = buf + used;
used += ret + 1;
}
continue;
}
if (str_has_prefix(argv[i], "$arg")) {
char *type = NULL;
n = simple_strtoul(argv[i] + 4, &type, 10);
if (type && !(*type == ':' || *type == '\0')) {
trace_probe_log_err(0, BAD_VAR);
ret = -ENOENT;
goto error;
}
/* Note: $argN starts from $arg1 */
ret = sprint_nth_btf_arg(n - 1, type, buf + used,
bufsize - used, ctx);
if (ret < 0)
goto error;
new_argv[j++] = buf + used;
used += ret + 1;
} else
new_argv[j++] = argv[i];
}
return new_argv;
error:
kfree(new_argv);
return ERR_PTR(ret);
}
void traceprobe_finish_parse(struct traceprobe_parse_context *ctx)
{
clear_btf_context(ctx);
}
int traceprobe_update_arg(struct probe_arg *arg)
{
struct fetch_insn *code = arg->code;
long offset;
char *tmp;
char c;
int ret = 0;
while (code && code->op != FETCH_OP_END) {
if (code->op == FETCH_NOP_SYMBOL) {
if (code[1].op != FETCH_OP_IMM)
return -EINVAL;
tmp = strpbrk(code->data, "+-");
if (tmp)
c = *tmp;
ret = traceprobe_split_symbol_offset(code->data,
&offset);
if (ret)
return ret;
code[1].immediate =
(unsigned long)kallsyms_lookup_name(code->data);
if (tmp)
*tmp = c;
if (!code[1].immediate)
return -ENOENT;
code[1].immediate += offset;
}
code++;
}
return 0;
}
/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)
static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
enum probe_print_type ptype)
{
struct probe_arg *parg;
int i, j;
int pos = 0;
const char *fmt, *arg;
switch (ptype) {
case PROBE_PRINT_NORMAL:
fmt = "(%lx)";
arg = ", REC->" FIELD_STRING_IP;
break;
case PROBE_PRINT_RETURN:
fmt = "(%lx <- %lx)";
arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
break;
case PROBE_PRINT_EVENT:
fmt = "";
arg = "";
break;
default:
WARN_ON_ONCE(1);
return 0;
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
for (i = 0; i < tp->nr_args; i++) {
parg = tp->args + i;
pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
if (parg->count) {
pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
parg->type->fmt);
for (j = 1; j < parg->count; j++)
pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
parg->type->fmt);
pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
} else
pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
parg->type->fmt);
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg);
for (i = 0; i < tp->nr_args; i++) {
parg = tp->args + i;
if (parg->count) {
if (parg->type->is_string)
fmt = ", __get_str(%s[%d])";
else
fmt = ", REC->%s[%d]";
for (j = 0; j < parg->count; j++)
pos += snprintf(buf + pos, LEN_OR_ZERO,
fmt, parg->name, j);
} else {
if (parg->type->is_string)
fmt = ", __get_str(%s)";
else
fmt = ", REC->%s";
pos += snprintf(buf + pos, LEN_OR_ZERO,
fmt, parg->name);
}
}
/* return the length of print_fmt */
return pos;
}
#undef LEN_OR_ZERO
int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
{
struct trace_event_call *call = trace_probe_event_call(tp);
int len;
char *print_fmt;
/* First: called with 0 length to calculate the needed length */
len = __set_print_fmt(tp, NULL, 0, ptype);
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, ptype);
call->print_fmt = print_fmt;
return 0;
}
int traceprobe_define_arg_fields(struct trace_event_call *event_call,
size_t offset, struct trace_probe *tp)
{
int ret, i;
/* Set argument names as fields */
for (i = 0; i < tp->nr_args; i++) {
struct probe_arg *parg = &tp->args[i];
const char *fmt = parg->type->fmttype;
int size = parg->type->size;
if (parg->fmt)
fmt = parg->fmt;
if (parg->count)
size *= parg->count;
ret = trace_define_field(event_call, fmt, parg->name,
offset + parg->offset, size,
parg->type->is_signed,
FILTER_OTHER);
if (ret)
return ret;
}
return 0;
}
static void trace_probe_event_free(struct trace_probe_event *tpe)
{
kfree(tpe->class.system);
kfree(tpe->call.name);
kfree(tpe->call.print_fmt);
kfree(tpe);
}
int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
{
if (trace_probe_has_sibling(tp))
return -EBUSY;
list_del_init(&tp->list);
trace_probe_event_free(tp->event);
tp->event = to->event;
list_add_tail(&tp->list, trace_probe_probe_list(to));
return 0;
}
void trace_probe_unlink(struct trace_probe *tp)
{
list_del_init(&tp->list);
if (list_empty(trace_probe_probe_list(tp)))
trace_probe_event_free(tp->event);
tp->event = NULL;
}
void trace_probe_cleanup(struct trace_probe *tp)
{
int i;
for (i = 0; i < tp->nr_args; i++)
traceprobe_free_probe_arg(&tp->args[i]);
if (tp->entry_arg) {
kfree(tp->entry_arg->code);
kfree(tp->entry_arg);
tp->entry_arg = NULL;
}
if (tp->event)
trace_probe_unlink(tp);
}
int trace_probe_init(struct trace_probe *tp, const char *event,
const char *group, bool alloc_filter, int nargs)
{
struct trace_event_call *call;
size_t size = sizeof(struct trace_probe_event);
int ret = 0;
if (!event || !group)
return -EINVAL;
if (alloc_filter)
size += sizeof(struct trace_uprobe_filter);
tp->event = kzalloc(size, GFP_KERNEL);
if (!tp->event)
return -ENOMEM;
INIT_LIST_HEAD(&tp->event->files);
INIT_LIST_HEAD(&tp->event->class.fields);
INIT_LIST_HEAD(&tp->event->probes);
INIT_LIST_HEAD(&tp->list);
list_add(&tp->list, &tp->event->probes);
call = trace_probe_event_call(tp);
call->class = &tp->event->class;
call->name = kstrdup(event, GFP_KERNEL);
if (!call->name) {
ret = -ENOMEM;
goto error;
}
tp->event->class.system = kstrdup(group, GFP_KERNEL);
if (!tp->event->class.system) {
ret = -ENOMEM;
goto error;
}
tp->nr_args = nargs;
/* Make sure pointers in args[] are NULL */
if (nargs)
memset(tp->args, 0, sizeof(tp->args[0]) * nargs);
return 0;
error:
trace_probe_cleanup(tp);
return ret;
}
static struct trace_event_call *
find_trace_event_call(const char *system, const char *event_name)
{
struct trace_event_call *tp_event;
const char *name;
list_for_each_entry(tp_event, &ftrace_events, list) {
if (!tp_event->class->system ||
strcmp(system, tp_event->class->system))
continue;
name = trace_event_name(tp_event);
if (!name || strcmp(event_name, name))
continue;
return tp_event;
}
return NULL;
}
int trace_probe_register_event_call(struct trace_probe *tp)
{
struct trace_event_call *call = trace_probe_event_call(tp);
int ret;
lockdep_assert_held(&event_mutex);
if (find_trace_event_call(trace_probe_group_name(tp),
trace_probe_name(tp)))
return -EEXIST;
ret = register_trace_event(&call->event);
if (!ret)
return -ENODEV;
ret = trace_add_event_call(call);
if (ret)
unregister_trace_event(&call->event);
return ret;
}
int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
{
struct event_file_link *link;
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link)
return -ENOMEM;
link->file = file;
INIT_LIST_HEAD(&link->list);
list_add_tail_rcu(&link->list, &tp->event->files);
trace_probe_set_flag(tp, TP_FLAG_TRACE);
return 0;
}
struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
struct trace_event_file *file)
{
struct event_file_link *link;
trace_probe_for_each_link(link, tp) {
if (link->file == file)
return link;
}
return NULL;
}
int trace_probe_remove_file(struct trace_probe *tp,
struct trace_event_file *file)
{
struct event_file_link *link;
link = trace_probe_get_file_link(tp, file);
if (!link)
return -ENOENT;
list_del_rcu(&link->list);
kvfree_rcu_mightsleep(link);
if (list_empty(&tp->event->files))
trace_probe_clear_flag(tp, TP_FLAG_TRACE);
return 0;
}
/*
* Return the smallest index of different type argument (start from 1).
* If all argument types and name are same, return 0.
*/
int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
{
int i;
/* In case of more arguments */
if (a->nr_args < b->nr_args)
return a->nr_args + 1;
if (a->nr_args > b->nr_args)
return b->nr_args + 1;
for (i = 0; i < a->nr_args; i++) {
if ((b->nr_args <= i) ||
((a->args[i].type != b->args[i].type) ||
(a->args[i].count != b->args[i].count) ||
strcmp(a->args[i].name, b->args[i].name)))
return i + 1;
}
return 0;
}
bool trace_probe_match_command_args(struct trace_probe *tp,
int argc, const char **argv)
{
char buf[MAX_ARGSTR_LEN + 1];
int i;
if (tp->nr_args < argc)
return false;
for (i = 0; i < argc; i++) {
snprintf(buf, sizeof(buf), "%s=%s",
tp->args[i].name, tp->args[i].comm);
if (strcmp(buf, argv[i]))
return false;
}
return true;
}
int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
{
int argc = 0, ret = 0;
char **argv;
argv = argv_split(GFP_KERNEL, raw_command, &argc);
if (!argv)
return -ENOMEM;
if (argc)
ret = createfn(argc, (const char **)argv);
argv_free(argv);
return ret;
}
int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args,
u8 *data, void *field)
{
void *p;
int i, j;
for (i = 0; i < nr_args; i++) {
struct probe_arg *a = args + i;
trace_seq_printf(s, " %s=", a->name);
if (likely(!a->count)) {
if (!a->type->print(s, data + a->offset, field))
return -ENOMEM;
continue;
}
trace_seq_putc(s, '{');
p = data + a->offset;
for (j = 0; j < a->count; j++) {
if (!a->type->print(s, p, field))
return -ENOMEM;
trace_seq_putc(s, j == a->count - 1 ? '}' : ',');
p += a->type->size;
}
}
return 0;
}