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sortix--sortix/libc/unistd/getlogin_r.cpp
Jonas 'Sortie' Termansen 8322d5f82c Fix getlogin_r memory leak.
2015-02-06 14:56:35 +01:00

59 lines
1.9 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
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/>.
unistd/getlogin_r.cpp
Get name of user logged in at the controlling terminal.
*******************************************************************************/
#include <errno.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
extern "C" int getlogin_r(char* buf, size_t size)
{
struct passwd passwd_object;
struct passwd* passwd;
int errnum = 0;
char* pwdbuf = NULL;
size_t pwdbuflen = 0;
do
{
// TODO: Potential overflow.
size_t new_pwdbuflen = pwdbuflen ? 2 * pwdbuflen : 64;
char* new_pwdbuf = (char*) realloc(pwdbuf, new_pwdbuflen);
if ( !new_pwdbuf )
return free(pwdbuf), -1;
pwdbuf = new_pwdbuf;
pwdbuflen = new_pwdbuflen;
} while ( (errnum = getpwuid_r(getuid(), &passwd_object, pwdbuf, pwdbuflen,
&passwd)) == ERANGE );
if ( errnum )
return free(pwdbuf), errno = errnum, -1;
const char* username = passwd->pw_name;
if ( size <= strlcpy(buf, username, size) )
return free(pwdbuf), errno = ERANGE, -1;
free(pwdbuf);
return 0;
}