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sortix--sortix/libc/stdlib/mkostemps.cpp
Jonas 'Sortie' Termansen f0e3e2cfef Add mkostemps(3) family.
2015-02-09 18:56:14 +01:00

66 lines
2 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013, 2014, 2015.
This file is part of the Sortix C Library.
The Sortix 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 3 of the License, or (at your
option) any later version.
The Sortix 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 Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
stdlib/mkostemps.cpp
Make a unique temporary file path and open it.
*******************************************************************************/
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
const uint32_t NUM_CHARACTERS = 10 + 26 + 26;
static inline char random_character()
{
uint32_t index = arc4random_uniform(NUM_CHARACTERS);
if ( index < 10 )
return '0' + index;
if ( index < 10 + 26 )
return 'a' + index - 10;
if ( index < 10 + 26 + 26 )
return 'A' + index - (10 + 26);
__builtin_unreachable();
}
extern "C" int mkostemps(char* templ, int suffixlen, int flags)
{
size_t templ_length = strlen(templ);
if ( templ_length < 6 ||
suffixlen < 0 ||
templ_length - 6 < (size_t) suffixlen )
return errno = EINVAL, -1;
size_t xpos = templ_length - (6 + suffixlen);
for ( size_t i = 0; i < 6; i++ )
if ( templ[xpos + i] != 'X' )
return errno = EINVAL, -1;
flags &= ~O_ACCMODE;
int fd;
do
{
for ( size_t i = 0; i < 6; i++ )
templ[xpos + i] = random_character();
} while ( (fd = open(templ, flags | O_RDWR | O_EXCL | O_CREAT, 0600)) < 0 &&
(errno == EEXIST) );
return fd;
}