glibc/sysdeps/generic/dl-tunables-parse.h

135 lines
3.5 KiB
C

/* Helper functions to handle tunable strings.
Copyright (C) 2023-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#ifndef _DL_TUNABLES_PARSE_H
#define _DL_TUNABLES_PARSE_H 1
#include <assert.h>
#include <string.h>
/* Compare the contents of STRVAL with STR of size LEN. The STR might not
be null-terminated. */
static __always_inline bool
tunable_strcmp (const struct tunable_str_t *strval, const char *str,
size_t len)
{
return strval->len == len && memcmp (strval->str, str, len) == 0;
}
#define tunable_strcmp_cte(__tunable, __str) \
tunable_strcmp (&__tunable->strval, __str, sizeof (__str) - 1)
/*
Helper functions to iterate over a tunable string composed by multiple
suboptions separated by commaxi; this is a common pattern for CPU. Each
suboptions is return in the form of { address, size } (no null terminated).
For instance:
struct tunable_str_comma_t ts;
tunable_str_comma_init (&ts, valp);
struct tunable_str_t t;
while (tunable_str_comma_next (&ts, &t))
{
_dl_printf ("[%s] %.*s (%d)\n",
__func__,
(int) tstr.len,
tstr.str,
(int) tstr.len);
if (tunable_str_comma_strcmp (&t, opt, opt1_len))
{
[...]
}
else if (tunable_str_comma_strcmp_cte (&t, "opt2"))
{
[...]
}
}
NB: These function are expected to be called from tunable callback
functions along with tunable_val_t with string types.
*/
struct tunable_str_comma_state_t
{
const char *p;
size_t plen;
size_t maxplen;
};
struct tunable_str_comma_t
{
const char *str;
size_t len;
bool disable;
};
static inline void
tunable_str_comma_init (struct tunable_str_comma_state_t *state,
tunable_val_t *valp)
{
assert (valp->strval.str != NULL);
state->p = valp->strval.str;
state->plen = 0;
state->maxplen = valp->strval.len;
}
static inline bool
tunable_str_comma_next (struct tunable_str_comma_state_t *state,
struct tunable_str_comma_t *str)
{
if (*state->p == '\0' || state->plen >= state->maxplen)
return false;
const char *c;
for (c = state->p; *c != ','; c++, state->plen++)
if (*c == '\0' || state->plen == state->maxplen)
break;
str->str = state->p;
str->len = c - state->p;
if (str->len > 0)
{
str->disable = *str->str == '-';
if (str->disable)
{
str->str = str->str + 1;
str->len = str->len - 1;
}
}
state->p = c + 1;
state->plen++;
return true;
}
/* Compare the contents of T with STR of size LEN. The STR might not be
null-terminated. */
static __always_inline bool
tunable_str_comma_strcmp (const struct tunable_str_comma_t *t, const char *str,
size_t len)
{
return t->len == len && memcmp (t->str, str, len) == 0;
}
#define tunable_str_comma_strcmp_cte(__t, __str) \
tunable_str_comma_strcmp (__t, __str, sizeof (__str) - 1)
#endif