glibc/libio/bits/stdio2.h
Xi Ruoyao 64b1a44183 libio: Add nonnull attribute for most FILE * arguments in stdio.h
During the review of a GCC analyzer test case, we found most stdio
functions accepting a FILE * argument expect it to be nonnull and just
segfault when the argument is NULL.  Add nonnull attribute for them.

fflush and fflush_unlocked are well defined when __stream is NULL so
they are not touched.

For fputs, fgets, fread, fwrite, fprintf, vfprintf, and their unlocked
version, if __stream is empty but there is nothing to read or write,
they did not segfault.  But the standard disallow __stream to be empty
here, so nonnull attribute is also added for them.  Note that this may
blow up some old code already subtly broken.

Also add __nonnull for _chk variants and __fortify_function versions for
them.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Reviewed-by: Alejandro Colomar <alx@kernel.org>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-09-26 20:11:38 -04:00

272 lines
8.0 KiB
C

/* Checking macros for stdio functions.
Copyright (C) 2004-2023 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 _BITS_STDIO2_H
#define _BITS_STDIO2_H 1
#ifndef _STDIO_H
# error "Never include <bits/stdio2.h> directly; use <stdio.h> instead."
#endif
#ifdef __va_arg_pack
__fortify_function int
__NTH (sprintf (char *__restrict __s, const char *__restrict __fmt, ...))
{
return __builtin___sprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
__glibc_objsize (__s), __fmt,
__va_arg_pack ());
}
#elif !defined __cplusplus
# define sprintf(str, ...) \
__builtin___sprintf_chk (str, __USE_FORTIFY_LEVEL - 1, \
__glibc_objsize (str), __VA_ARGS__)
#endif
__fortify_function int
__NTH (vsprintf (char *__restrict __s, const char *__restrict __fmt,
__gnuc_va_list __ap))
{
return __builtin___vsprintf_chk (__s, __USE_FORTIFY_LEVEL - 1,
__glibc_objsize (__s), __fmt, __ap);
}
#if defined __USE_ISOC99 || defined __USE_UNIX98
# ifdef __va_arg_pack
__fortify_function int
__NTH (snprintf (char *__restrict __s, size_t __n,
const char *__restrict __fmt, ...))
{
return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
__glibc_objsize (__s), __fmt,
__va_arg_pack ());
}
# elif !defined __cplusplus
# define snprintf(str, len, ...) \
__builtin___snprintf_chk (str, len, __USE_FORTIFY_LEVEL - 1, \
__glibc_objsize (str), __VA_ARGS__)
# endif
__fortify_function int
__NTH (vsnprintf (char *__restrict __s, size_t __n,
const char *__restrict __fmt, __gnuc_va_list __ap))
{
return __builtin___vsnprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
__glibc_objsize (__s), __fmt, __ap);
}
#endif
#if __USE_FORTIFY_LEVEL > 1
# ifdef __va_arg_pack
__fortify_function __nonnull ((1)) int
fprintf (FILE *__restrict __stream, const char *__restrict __fmt, ...)
{
return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
__va_arg_pack ());
}
__fortify_function int
printf (const char *__restrict __fmt, ...)
{
return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __va_arg_pack ());
}
# elif !defined __cplusplus
# define printf(...) \
__printf_chk (__USE_FORTIFY_LEVEL - 1, __VA_ARGS__)
# define fprintf(stream, ...) \
__fprintf_chk (stream, __USE_FORTIFY_LEVEL - 1, __VA_ARGS__)
# endif
__fortify_function int
vprintf (const char *__restrict __fmt, __gnuc_va_list __ap)
{
#ifdef __USE_EXTERN_INLINES
return __vfprintf_chk (stdout, __USE_FORTIFY_LEVEL - 1, __fmt, __ap);
#else
return __vprintf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, __ap);
#endif
}
__fortify_function __nonnull ((1)) int
vfprintf (FILE *__restrict __stream,
const char *__restrict __fmt, __gnuc_va_list __ap)
{
return __vfprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt, __ap);
}
# ifdef __USE_XOPEN2K8
# ifdef __va_arg_pack
__fortify_function int
dprintf (int __fd, const char *__restrict __fmt, ...)
{
return __dprintf_chk (__fd, __USE_FORTIFY_LEVEL - 1, __fmt,
__va_arg_pack ());
}
# elif !defined __cplusplus
# define dprintf(fd, ...) \
__dprintf_chk (fd, __USE_FORTIFY_LEVEL - 1, __VA_ARGS__)
# endif
__fortify_function int
vdprintf (int __fd, const char *__restrict __fmt, __gnuc_va_list __ap)
{
return __vdprintf_chk (__fd, __USE_FORTIFY_LEVEL - 1, __fmt, __ap);
}
# endif
# ifdef __USE_GNU
# ifdef __va_arg_pack
__fortify_function int
__NTH (asprintf (char **__restrict __ptr, const char *__restrict __fmt, ...))
{
return __asprintf_chk (__ptr, __USE_FORTIFY_LEVEL - 1, __fmt,
__va_arg_pack ());
}
__fortify_function int
__NTH (__asprintf (char **__restrict __ptr, const char *__restrict __fmt,
...))
{
return __asprintf_chk (__ptr, __USE_FORTIFY_LEVEL - 1, __fmt,
__va_arg_pack ());
}
__fortify_function int
__NTH (obstack_printf (struct obstack *__restrict __obstack,
const char *__restrict __fmt, ...))
{
return __obstack_printf_chk (__obstack, __USE_FORTIFY_LEVEL - 1, __fmt,
__va_arg_pack ());
}
# elif !defined __cplusplus
# define asprintf(ptr, ...) \
__asprintf_chk (ptr, __USE_FORTIFY_LEVEL - 1, __VA_ARGS__)
# define __asprintf(ptr, ...) \
__asprintf_chk (ptr, __USE_FORTIFY_LEVEL - 1, __VA_ARGS__)
# define obstack_printf(obstack, ...) \
__obstack_printf_chk (obstack, __USE_FORTIFY_LEVEL - 1, __VA_ARGS__)
# endif
__fortify_function int
__NTH (vasprintf (char **__restrict __ptr, const char *__restrict __fmt,
__gnuc_va_list __ap))
{
return __vasprintf_chk (__ptr, __USE_FORTIFY_LEVEL - 1, __fmt, __ap);
}
__fortify_function int
__NTH (obstack_vprintf (struct obstack *__restrict __obstack,
const char *__restrict __fmt, __gnuc_va_list __ap))
{
return __obstack_vprintf_chk (__obstack, __USE_FORTIFY_LEVEL - 1, __fmt,
__ap);
}
# endif
#endif
#if __GLIBC_USE (DEPRECATED_GETS)
__fortify_function __wur char *
gets (char *__str)
{
if (__glibc_objsize (__str) != (size_t) -1)
return __gets_chk (__str, __glibc_objsize (__str));
return __gets_warn (__str);
}
#endif
__fortify_function __wur __fortified_attr_access (__write_only__, 1, 2)
__nonnull ((3)) char *
fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
{
size_t sz = __glibc_objsize (__s);
if (__glibc_safe_or_unknown_len (__n, sizeof (char), sz))
return __fgets_alias (__s, __n, __stream);
if (__glibc_unsafe_len (__n, sizeof (char), sz))
return __fgets_chk_warn (__s, sz, __n, __stream);
return __fgets_chk (__s, sz, __n, __stream);
}
__fortify_function __wur __nonnull ((4)) size_t
fread (void *__restrict __ptr, size_t __size, size_t __n,
FILE *__restrict __stream)
{
size_t sz = __glibc_objsize0 (__ptr);
if (__glibc_safe_or_unknown_len (__n, __size, sz))
return __fread_alias (__ptr, __size, __n, __stream);
if (__glibc_unsafe_len (__n, __size, sz))
return __fread_chk_warn (__ptr, sz, __size, __n, __stream);
return __fread_chk (__ptr, sz, __size, __n, __stream);
}
#ifdef __USE_GNU
__fortify_function __wur __fortified_attr_access (__write_only__, 1, 2)
__nonnull ((3)) char *
fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream)
{
size_t sz = __glibc_objsize (__s);
if (__glibc_safe_or_unknown_len (__n, sizeof (char), sz))
return __fgets_unlocked_alias (__s, __n, __stream);
if (__glibc_unsafe_len (__n, sizeof (char), sz))
return __fgets_unlocked_chk_warn (__s, sz, __n, __stream);
return __fgets_unlocked_chk (__s, sz, __n, __stream);
}
#endif
#ifdef __USE_MISC
# undef fread_unlocked
__fortify_function __wur __nonnull ((4)) size_t
fread_unlocked (void *__restrict __ptr, size_t __size, size_t __n,
FILE *__restrict __stream)
{
size_t sz = __glibc_objsize0 (__ptr);
if (__glibc_safe_or_unknown_len (__n, __size, sz))
{
# ifdef __USE_EXTERN_INLINES
if (__builtin_constant_p (__size)
&& __builtin_constant_p (__n)
&& (__size | __n) < (((size_t) 1) << (8 * sizeof (size_t) / 2))
&& __size * __n <= 8)
{
size_t __cnt = __size * __n;
char *__cptr = (char *) __ptr;
if (__cnt == 0)
return 0;
for (; __cnt > 0; --__cnt)
{
int __c = getc_unlocked (__stream);
if (__c == EOF)
break;
*__cptr++ = __c;
}
return (__cptr - (char *) __ptr) / __size;
}
# endif
return __fread_unlocked_alias (__ptr, __size, __n, __stream);
}
if (__glibc_unsafe_len (__n, __size, sz))
return __fread_unlocked_chk_warn (__ptr, sz, __size, __n, __stream);
return __fread_unlocked_chk (__ptr, sz, __size, __n, __stream);
}
#endif
#endif /* bits/stdio2.h. */