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trace_probe.c
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// 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 <[email protected]>
*
* 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_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 struct btf *traceprobe_get_btf(void)
{
struct btf *btf = bpf_get_btf_vmlinux();
if (IS_ERR_OR_NULL(btf))
return NULL;
return btf;
}
static u32 btf_type_int(const struct btf_type *t)
{
return *(u32 *)(t + 1);
}
static const char *type_from_btf_id(struct btf *btf, s32 id)
{
const struct btf_type *t;
u32 intdata;
s32 tid;
/* TODO: const char * could be converted as a string */
t = btf_type_skip_modifiers(btf, id, &tid);
switch (BTF_INFO_KIND(t->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(t);
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";
}
}
}
/* TODO: support other types */
return NULL;
}
static const struct btf_type *find_btf_func_proto(const char *funcname)
{
struct btf *btf = traceprobe_get_btf();
const struct btf_type *t;
s32 id;
if (!btf || !funcname)
return ERR_PTR(-EINVAL);
id = btf_find_by_name_kind(btf, funcname, BTF_KIND_FUNC);
if (id <= 0)
return ERR_PTR(-ENOENT);
/* Get BTF_KIND_FUNC type */
t = btf_type_by_id(btf, id);
if (!t || !btf_type_is_func(t))
return ERR_PTR(-ENOENT);
/* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
t = btf_type_by_id(btf, t->type);
if (!t || !btf_type_is_func_proto(t))
return ERR_PTR(-ENOENT);
return t;
}
static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr,
bool tracepoint)
{
const struct btf_param *param;
const struct btf_type *t;
if (!funcname || !nr)
return ERR_PTR(-EINVAL);
t = find_btf_func_proto(funcname);
if (IS_ERR(t))
return (const struct btf_param *)t;
*nr = btf_type_vlen(t);
param = (const struct btf_param *)(t + 1);
/* Hide the first 'data' argument of tracepoint */
if (tracepoint) {
(*nr)--;
param++;
}
if (*nr > 0)
return param;
else
return NULL;
}
static int parse_btf_arg(const char *varname, struct fetch_insn *code,
struct traceprobe_parse_context *ctx)
{
struct btf *btf = traceprobe_get_btf();
const struct btf_param *params;
int i;
if (!btf) {
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EOPNOTSUPP;
}
if (WARN_ON_ONCE(!ctx->funcname))
return -EINVAL;
if (!ctx->params) {
params = find_btf_func_param(ctx->funcname, &ctx->nr_params,
ctx->flags & TPARG_FL_TPOINT);
if (IS_ERR_OR_NULL(params)) {
trace_probe_log_err(ctx->offset, NO_BTF_ENTRY);
return PTR_ERR(params);
}
ctx->params = params;
} else
params = ctx->params;
for (i = 0; i < ctx->nr_params; i++) {
const char *name = btf_name_by_offset(btf, params[i].name_off);
if (name && !strcmp(name, varname)) {
code->op = FETCH_OP_ARG;
if (ctx->flags & TPARG_FL_TPOINT)
code->param = i + 1;
else
code->param = i;
return 0;
}
}
trace_probe_log_err(ctx->offset, NO_BTFARG);
return -ENOENT;
}
static const struct fetch_type *parse_btf_arg_type(int arg_idx,
struct traceprobe_parse_context *ctx)
{
struct btf *btf = traceprobe_get_btf();
const char *typestr = NULL;
if (btf && ctx->params) {
if (ctx->flags & TPARG_FL_TPOINT)
arg_idx--;
typestr = type_from_btf_id(btf, ctx->params[arg_idx].type);
}
return find_fetch_type(typestr, ctx->flags);
}
static const struct fetch_type *parse_btf_retval_type(
struct traceprobe_parse_context *ctx)
{
struct btf *btf = traceprobe_get_btf();
const char *typestr = NULL;
const struct btf_type *t;
if (btf && ctx->funcname) {
t = find_btf_func_proto(ctx->funcname);
if (!IS_ERR(t))
typestr = type_from_btf_id(btf, t->type);
}
return find_fetch_type(typestr, ctx->flags);
}
static bool is_btf_retval_void(const char *funcname)
{
const struct btf_type *t;
t = find_btf_func_proto(funcname);
if (IS_ERR(t))
return false;
return t->type == 0;
}
#else
static struct btf *traceprobe_get_btf(void)
{
return NULL;
}
static const struct btf_param *find_btf_func_param(const char *funcname, s32 *nr,
bool tracepoint)
{
return ERR_PTR(-EOPNOTSUPP);
}
static int parse_btf_arg(const char *varname, struct fetch_insn *code,
struct traceprobe_parse_context *ctx)
{
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EOPNOTSUPP;
}
#define parse_btf_arg_type(idx, ctx) \
find_fetch_type(NULL, ctx->flags)
#define parse_btf_retval_type(ctx) \
find_fetch_type(NULL, ctx->flags)
#define is_btf_retval_void(funcname) (false)
#endif
#define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
static int parse_probe_vars(char *arg, const struct fetch_type *t,
struct fetch_insn *code,
struct traceprobe_parse_context *ctx)
{
unsigned long param;
int err = TP_ERR_BAD_VAR;
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 (strcmp(arg, "retval") == 0) {
if (ctx->flags & TPARG_FL_RETURN) {
if ((ctx->flags & TPARG_FL_KERNEL) &&
is_btf_retval_void(ctx->funcname)) {
err = TP_ERR_NO_RETVAL;
goto inval;
}
code->op = FETCH_OP_RETVAL;
return 0;
}
err = TP_ERR_RETVAL_ON_PROBE;
goto inval;
}
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, ¶m);
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 && tparg_is_function_entry(ctx->flags)) {
ret = kstrtoul(arg + len, 10, ¶m);
if (ret)
goto inval;
if (!param || param > PARAM_MAX_STACK) {
err = TP_ERR_BAD_ARG_NUM;
goto inval;
}
code->op = FETCH_OP_ARG;
code->param = (unsigned int)param - 1;
/*
* 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++;
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 + 1, type, code, 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, ¶m);
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;
}
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)) {
trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
return -EINVAL;
}
ret = parse_btf_arg(arg, code, 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;
}
/* 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, *scode, *tmp = NULL;
char *t, *t2, *t3;
int ret, len;
char *arg;
arg = kstrdup(argv, GFP_KERNEL);
if (!arg)
return -ENOMEM;
ret = -EINVAL;
len = strlen(arg);
if (len > MAX_ARGSTR_LEN) {
trace_probe_log_err(ctx->offset, ARG_TOO_LONG);
goto out;
} else if (len == 0) {
trace_probe_log_err(ctx->offset, NO_ARG_BODY);
goto out;
}
ret = -ENOMEM;
parg->comm = kstrdup(arg, GFP_KERNEL);
if (!parg->comm)
goto out;
ret = -EINVAL;
t = strchr(arg, ':');
if (t) {
*t = '\0';
t2 = strchr(++t, '[');
if (t2) {
*t2++ = '\0';
t3 = strchr(t2, ']');
if (!t3) {
int offs = t2 + strlen(t2) - arg;
trace_probe_log_err(ctx->offset + offs,
ARRAY_NO_CLOSE);
goto out;
} else if (t3[1] != '\0') {
trace_probe_log_err(ctx->offset + t3 + 1 - arg,
BAD_ARRAY_SUFFIX);
goto out;
}
*t3 = '\0';
if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
trace_probe_log_err(ctx->offset + t2 - arg,
BAD_ARRAY_NUM);
goto out;
}
if (parg->count > MAX_ARRAY_LEN) {
trace_probe_log_err(ctx->offset + t2 - arg,
ARRAY_TOO_BIG);
goto out;
}
}
}
/*
* 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. */
if (parg->count || (t && strcmp(t, "string")))
goto out;
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 + (t ? (t - arg) : 0), BAD_TYPE);
goto out;
}
parg->offset = *size;
*size += parg->type->size * (parg->count ?: 1);
ret = -ENOMEM;
if (parg->count) {
len = strlen(parg->type->fmttype) + 6;
parg->fmt = kmalloc(len, GFP_KERNEL);
if (!parg->fmt)
goto out;
snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
parg->count);
}
code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
if (!code)
goto out;
code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
ctx);
if (ret)
goto fail;
/* Update storing type if BTF is available */
if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && !t) {
if (code->op == FETCH_OP_ARG)
parg->type = parse_btf_arg_type(code->param, ctx);
else if (code->op == FETCH_OP_RETVAL)
parg->type = parse_btf_retval_type(ctx);
}
ret = -EINVAL;
/* Store operation */
if (parg->type->is_string) {
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 + (t ? (t - arg) : 0),
BAD_SYMSTRING);
goto fail;
}
} 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 + (t ? (t - arg) : 0),
BAD_STRING);
goto fail;
}
}
if (!strcmp(parg->type->name, "symstr") ||