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dff8da6b | 1 | /* Copyright (C) 1993-2024 Free Software Foundation, Inc. |
41bdb6e2 | 2 | This file is part of the GNU C Library. |
40a55d20 | 3 | |
41bdb6e2 AJ |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
40a55d20 | 8 | |
41bdb6e2 AJ |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
40a55d20 | 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
41bdb6e2 AJ |
12 | Lesser General Public License for more details. |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. |
41bdb6e2 AJ |
17 | |
18 | As a special exception, if you link the code in this file with | |
19 | files compiled with a GNU compiler to produce an executable, | |
20 | that does not cause the resulting executable to be covered by | |
21 | the GNU Lesser General Public License. This exception does not | |
22 | however invalidate any other reasons why the executable file | |
23 | might be covered by the GNU Lesser General Public License. | |
24 | This exception applies to code released by its copyright holders | |
25 | in files containing the exception. */ | |
96aa2d94 RM |
26 | |
27 | #include "libioP.h" | |
96aa2d94 | 28 | |
fb9bd841 FW |
29 | #include <printf.h> |
30 | #include <stdint.h> | |
31 | #include <printf_buffer.h> | |
4e2f43f8 | 32 | |
96aa2d94 | 33 | int |
4e2f43f8 ZW |
34 | __vsprintf_internal (char *string, size_t maxlen, |
35 | const char *format, va_list args, | |
698fb75b | 36 | unsigned int mode_flags) |
96aa2d94 | 37 | { |
fb9bd841 | 38 | struct __printf_buffer buf; |
edf5b2d7 | 39 | |
2d9837c1 GG |
40 | /* When called from fortified sprintf/vsprintf, erase the destination |
41 | buffer and try to detect overflows. When called from regular | |
42 | sprintf/vsprintf, do not erase the destination buffer, because | |
43 | known user code relies on this behavior (even though its undefined | |
44 | by ISO C), nor try to detect overflows. */ | |
45 | if ((mode_flags & PRINTF_CHK) != 0) | |
46 | { | |
2d9837c1 | 47 | string[0] = '\0'; |
0d50f477 FW |
48 | /* In some cases, __sprintf_chk is called with an unknown buffer |
49 | size (the special value -1). Prevent pointer wraparound in | |
50 | this case and saturate to the end of the address space. */ | |
51 | uintptr_t end; | |
52 | if (__builtin_add_overflow ((uintptr_t) string, maxlen, &end)) | |
53 | end = -1; | |
54 | __printf_buffer_init_end (&buf, string, (char *) end, | |
fb9bd841 | 55 | __printf_buffer_mode_sprintf_chk); |
2d9837c1 GG |
56 | } |
57 | else | |
0d50f477 FW |
58 | /* Use end of address space. */ |
59 | __printf_buffer_init_end (&buf, string, (char *) ~(uintptr_t) 0, | |
60 | __printf_buffer_mode_sprintf); | |
fb9bd841 FW |
61 | |
62 | __printf_buffer (&buf, format, args, mode_flags); | |
4e2f43f8 | 63 | |
fb9bd841 FW |
64 | /* Write the NUL terminator if there is room. Do not use the putc |
65 | operation to avoid overflowing the character write count. */ | |
66 | if ((mode_flags & PRINTF_CHK) != 0 && buf.write_ptr == buf.write_end) | |
67 | __chk_fail (); | |
68 | *buf.write_ptr = '\0'; | |
4e2f43f8 | 69 | |
fb9bd841 | 70 | return __printf_buffer_done (&buf); |
96aa2d94 RM |
71 | } |
72 | ||
698fb75b ZW |
73 | int |
74 | __vsprintf (char *string, const char *format, va_list args) | |
75 | { | |
4e2f43f8 | 76 | return __vsprintf_internal (string, -1, format, args, 0); |
698fb75b ZW |
77 | } |
78 | ||
79 | ldbl_strong_alias (__vsprintf, _IO_vsprintf) | |
80 | ldbl_weak_alias (__vsprintf, vsprintf) |