freebsd-dev/lib/libc/gen/getutxent.c
Ed Schouten 126b6df920 Make utmpx(3) thread safe if we support TLS.
Because the utmpx interface is generally not required to be thread-safe,
but it is nice to have, if easy to do so. Therefore don't make a mess
out of the code and only use it if __NO_TLS is not defined.
2012-03-23 08:26:31 +00:00

236 lines
4.6 KiB
C

/*-
* Copyright (c) 2010 Ed Schouten <ed@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <sys/endian.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <utmpx.h>
#include "utxdb.h"
#include "un-namespace.h"
#ifdef __NO_TLS
static FILE *uf = NULL;
static int udb;
#else
static _Thread_local FILE *uf = NULL;
static _Thread_local int udb;
#endif
int
setutxdb(int db, const char *file)
{
struct stat sb;
switch (db) {
case UTXDB_ACTIVE:
if (file == NULL)
file = _PATH_UTX_ACTIVE;
break;
case UTXDB_LASTLOGIN:
if (file == NULL)
file = _PATH_UTX_LASTLOGIN;
break;
case UTXDB_LOG:
if (file == NULL)
file = _PATH_UTX_LOG;
break;
default:
errno = EINVAL;
return (-1);
}
if (uf != NULL)
fclose(uf);
uf = fopen(file, "r");
if (uf == NULL)
return (-1);
if (db != UTXDB_LOG) {
/* Safety check: never use broken files. */
if (_fstat(fileno(uf), &sb) != -1 &&
sb.st_size % sizeof(struct futx) != 0) {
fclose(uf);
uf = NULL;
errno = EFTYPE;
return (-1);
}
/* Prevent reading of partial records. */
(void)setvbuf(uf, NULL, _IOFBF,
rounddown(BUFSIZ, sizeof(struct futx)));
}
udb = db;
return (0);
}
void
setutxent(void)
{
setutxdb(UTXDB_ACTIVE, NULL);
}
void
endutxent(void)
{
if (uf != NULL) {
fclose(uf);
uf = NULL;
}
}
static int
getfutxent(struct futx *fu)
{
if (uf == NULL)
setutxent();
if (uf == NULL)
return (-1);
if (udb == UTXDB_LOG) {
uint16_t len;
if (fread(&len, sizeof(len), 1, uf) != 1)
return (-1);
len = be16toh(len);
if (len > sizeof *fu) {
/* Forward compatibility. */
if (fread(fu, sizeof(*fu), 1, uf) != 1)
return (-1);
fseek(uf, len - sizeof(*fu), SEEK_CUR);
} else {
/* Partial record. */
memset(fu, 0, sizeof(*fu));
if (fread(fu, len, 1, uf) != 1)
return (-1);
}
} else {
if (fread(fu, sizeof(*fu), 1, uf) != 1)
return (-1);
}
return (0);
}
struct utmpx *
getutxent(void)
{
struct futx fu;
if (getfutxent(&fu) != 0)
return (NULL);
return (futx_to_utx(&fu));
}
struct utmpx *
getutxid(const struct utmpx *id)
{
struct futx fu;
for (;;) {
if (getfutxent(&fu) != 0)
return (NULL);
switch (fu.fu_type) {
case USER_PROCESS:
case INIT_PROCESS:
case LOGIN_PROCESS:
case DEAD_PROCESS:
switch (id->ut_type) {
case USER_PROCESS:
case INIT_PROCESS:
case LOGIN_PROCESS:
case DEAD_PROCESS:
if (memcmp(fu.fu_id, id->ut_id,
MIN(sizeof(fu.fu_id), sizeof(id->ut_id))) ==
0)
goto found;
}
break;
default:
if (fu.fu_type == id->ut_type)
goto found;
break;
}
}
found:
return (futx_to_utx(&fu));
}
struct utmpx *
getutxline(const struct utmpx *line)
{
struct futx fu;
for (;;) {
if (getfutxent(&fu) != 0)
return (NULL);
switch (fu.fu_type) {
case USER_PROCESS:
case LOGIN_PROCESS:
if (strncmp(fu.fu_line, line->ut_line,
MIN(sizeof(fu.fu_line), sizeof(line->ut_line))) ==
0)
goto found;
break;
}
}
found:
return (futx_to_utx(&fu));
}
struct utmpx *
getutxuser(const char *user)
{
struct futx fu;
for (;;) {
if (getfutxent(&fu) != 0)
return (NULL);
switch (fu.fu_type) {
case USER_PROCESS:
if (strncmp(fu.fu_user, user, sizeof(fu.fu_user)) == 0)
goto found;
break;
}
}
found:
return (futx_to_utx(&fu));
}