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sortix--sortix/libc/unistd/getlogin_r.c
Jonas 'Sortie' Termansen 11be0007b8 Remove ENOUSER and ENOGROUP.
The <pwd.h> and <grp.h> family of functions are supposed to return
nothing with no error set if there is no matching entry.
2021-05-10 23:26:31 +02:00

56 lines
1.8 KiB
C

/*
* Copyright (c) 2013, 2021 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* unistd/getlogin_r.c
* 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>
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;
if ( !passwd )
return free(pwdbuf), errno = ENOENT, -1;
const char* username = passwd->pw_name;
if ( size <= strlcpy(buf, username, size) )
return free(pwdbuf), errno = ERANGE, -1;
free(pwdbuf);
return 0;
}