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/*===========================================================================*
* *
* sfluid.c - User and group ID functions *
* *
* Copyright (c) 1991-2010 iMatix Corporation *
* *
* ------------------ GPL Licensed Source Code ------------------ *
* iMatix makes this software available under the GNU General *
* Public License (GPL) license for open source projects. For *
* details of the GPL license please see www.gnu.org or read the *
* file license.gpl provided in this package. *
* *
* This program is free software; you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation; either version 3 of *
* the License, or (at your option) any later version. *
* *
* This program 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 General Public License for more details. *
* *
* You should have received a copy of the GNU General Public *
* License along with this program in the file 'license.gpl'; if *
* not, see <http://www.gnu.org/licenses/>. *
* *
* You can also license this software under iMatix's General Terms *
* of Business (GTB) for commercial projects. If you have not *
* explicitly licensed this software under the iMatix GTB you may *
* only use it under the terms of the GNU General Public License. *
* *
* For more information, send an email to info@imatix.com. *
* -------------------------------------------------------------- *
*===========================================================================*/
#include "prelude.h" /* Universal header file */
#include "sflstr.h" /* String functions */
#include "sfluid.h" /* Prototypes for functions */
/* Local constants and function prototypes */
#define UID_CACHE_MAX 10 /* Max. different uid's we cache */
#define GID_CACHE_MAX 10 /* Max. different gid's we cache */
#define REAL_ID 0 /* Arguments for get_uid/get_gid */
#define EFFECTIVE_ID 1
#if (defined (DOES_UID)) /* Only if uid/gid implemented */
# if (!defined (__OS2__)) /* But not needed under OS/2 */
static uid_t get_uid (int type);
# endif
# if (!defined (__VMS__)) /* No gid under OpenVMS */
static gid_t get_gid (int type);
# endif
#endif
/* ---------------------------------------------------------------------[<]-
Function: get_uid_name
Synopsis:
Get user name from passwd file. We optimise by keeping a table of uids
and names in memory. Note that this will cause problems if the program
stays running when the passwd file has been changed. Returns a string
containing the translated user name, or "<none>" if the uid could not
be translated. Under MS-DOS the uid must be zero. The returned string
is in a static area that is _not_ overwritten with each call, but which
should be treated as read-only, and unstable: i.e. the value returned
by one call to get_uid_name may change as a result of a later call. If
you need persistent strings, use strdupl() after each call.
---------------------------------------------------------------------[>]-*/
char *
get_uid_name (uid_t uid)
{
# if (defined (DOES_UID))
static struct uids { /* Table of cached uids */
uid_t id;
char *name;
} cache [UID_CACHE_MAX];
static int
cache_size = 0, /* Number of uid's in cache */
cache_oldest = 0; /* Oldest entry in cache */
int
cache_scan; /* Scan through cache */
struct passwd
*passwd_entry;
/* First, look for uid in cache */
for (cache_scan = 0; cache_scan < cache_size; cache_scan++)
if (cache [cache_scan].id == uid)
return (cache [cache_scan].name);
/* Add new name to cache: if cache was full, kick-out oldest entry */
if (cache_size == UID_CACHE_MAX)
{
cache_scan = cache_oldest++;
cache_oldest %= UID_CACHE_MAX;
free (cache [cache_scan].name);
}
else
cache_scan = cache_size++;
cache [cache_scan].id = uid;
if ((passwd_entry = getpwuid (uid)) == NULL)
cache [cache_scan].name = "<none>";
else
cache [cache_scan].name = strdupl (passwd_entry-> pw_name);
return (cache [cache_scan].name);
# elif (defined (__MSDOS__))
return (uid == 0? "user": "<none>");
# endif
}
/* ---------------------------------------------------------------------[<]-
Function: get_gid_name
Synopsis:
Get group name from group file. We optimise by keeping a table of gids
and names in memory. Note that this will cause problems if the program
stays running when the group file has been changed. Returns a string
containing the translated user name, or "<none>" if the gid could not
be translated. Under MS-DOS the gid must be zero. The returned string
is in a static area that is _not_ overwritten with each call, but which
should be treated as read-only, and unstable: i.e. the value returned
by one call to get_gid_name may change as a result of a later call. If
you need persistent strings, use strdupl() after each call.
---------------------------------------------------------------------[>]-*/
char *
get_gid_name (gid_t gid)
{
# if (defined (DOES_UID))
static struct gids { /* Table of cache'd gids */
gid_t id;
char *name;
} cache [GID_CACHE_MAX];
static int
cache_size = 0, /* Number of gid's in cache */
cache_oldest = 0; /* Oldest entry in cache */
int
cache_scan; /* Scan through cache */
struct group
*group_entry;
/* First, look for gid in cache */
for (cache_scan = 0; cache_scan < cache_size; cache_scan++)
if (cache [cache_scan].id == gid)
return (cache [cache_scan].name);
/* Add new name to cache: if cache was full, kick-out oldest entry */
if (cache_size == GID_CACHE_MAX)
{
cache_scan = cache_oldest++;
cache_oldest %= GID_CACHE_MAX;
free (cache [cache_scan].name);
}
else
cache_scan = cache_size++;
cache [cache_scan].id = gid;
# if (defined (__VMS__))
cache [cache_scan].name = "<none>";
# else
if ((group_entry = getgrgid (gid)) == NULL)
cache [cache_scan].name = "<none>";
else
cache [cache_scan].name = strdupl (group_entry-> gr_name);
# endif
return (cache [cache_scan].name);
# elif (defined (__MSDOS__))
return (gid == 0? "group": "<none>");
# endif
}
/* ---------------------------------------------------------------------[<]-
Function: set_uid_user
Synopsis: This function can be used by 'setuid' programs; i.e. programs
that run under a fixed uid such as 'root'. Typically such programs need
to access root resources, but user data files. To do this they must
switch between the 'root' uid and the 'user' uid. This function switches
to the real user id. Use set_uid_root() to switch (back) to the 'root'
uid. See also: set_gid_user() and set_gid_root().
---------------------------------------------------------------------[>]-*/
int
set_uid_user (void)
{
#if (defined (DOES_UID))
# if (defined (__UTYPE_HPUX) || defined (__UTYPE_BEOS))
return (setuid (get_uid (REAL_ID)));
# elif (defined (__OS2__)) /* OS/2 only supports one UID */
return (0);
# elif (defined (__VMS__)) /* No setuid under OpenVMS */
return (0);
# else
return (seteuid (get_uid (REAL_ID)));
# endif
#else
return (0);
#endif
}
/* ---------------------------------------------------------------------[<]-
Function: set_uid_root
Synopsis: This function can be used by 'setuid' programs; i.e. programs
that run under a fixed uid such as 'root'. Typically such programs need
to access root resources, but user data files. To do this they must
switch between the 'root' uid and the 'user' uid. This function switches
back to the root user id. Use set_uid_user() to switch to the 'user'
uid. See also: set_gid_user() and set_gid_root().
---------------------------------------------------------------------[>]-*/
int
set_uid_root (void)
{
#if (defined (DOES_UID))
# if (defined (__UTYPE_HPUX) || defined (__UTYPE_BEOS))
return (setuid (get_uid (EFFECTIVE_ID)));
# elif (defined (__OS2__)) /* OS/2 only supports one UID */
return (0);
# elif (defined (__VMS__)) /* No setuid under OpenVMS */
return (0);
# else
return (seteuid (get_uid (EFFECTIVE_ID)));
# endif
#else
return (0);
#endif
}
#if (defined (DOES_UID) && !defined (__OS2__))
/* -------------------------------------------------------------------------
Function: get_uid_id -- internal
Synopsis: Returns the real (REAL_ID) or effective (EFFECTIVE_ID) uid.
These values are loaded the first time that the function is called: you
should not rely on the effective uid after changing the uid.
-------------------------------------------------------------------------*/
static uid_t
get_uid (int type)
{
static int
ruid = -1,
euid = -1;
if (ruid == -1)
ruid = getuid ();
if (euid == -1)
# if (defined (__UTYPE_HPUX) || defined (__UTYPE_BEOS))
euid = getuid ();
# else
euid = geteuid ();
# endif
if (type == REAL_ID)
return (ruid);
else
if (type == EFFECTIVE_ID)
return (euid);
else
return (-1);
}
#endif
/* ---------------------------------------------------------------------[<]-
Function: set_gid_user
Synopsis: This function can be used by 'setgid' programs; i.e. programs
that run under a fixed gid such as 'root'. Typically such programs need
to access root resources, but user data files. To do this they must
switch between the 'root' gid and the 'user' gid. This function switches
to the real user id. Use set_gid_root() to switch (back) to the 'root'
gid. See also: set_uid_user() and set_uid_root().
---------------------------------------------------------------------[>]-*/
int
set_gid_user (void)
{
#if (defined (DOES_UID))
# if (defined (__UTYPE_HPUX) || defined (__UTYPE_BEOS))
return (setgid (get_gid (REAL_ID)));
# elif (defined (__OS2__)) /* OS/2 only supports one UID */
return (0);
# elif (defined (__VMS__)) /* No setgid under OpenVMS */
return (0);
# else
return (setegid (get_gid (REAL_ID)));
# endif
#else
return (0);
#endif
}
/* ---------------------------------------------------------------------[<]-
Function: set_gid_root
Synopsis: This function can be used by 'setgid' programs; i.e. programs
that run under a fixed gid such as 'root'. Typically such programs need
to access root resources, but user data files. To do this they must
switch between the 'root' gid and the 'user' gid. This function switches
back to the root user id. Use set_gid_user() to switch to the 'user'
gid. See also: set_gid_user() and set_gid_root().
---------------------------------------------------------------------[>]-*/
int
set_gid_root (void)
{
#if (defined (DOES_UID))
# if (defined (__UTYPE_HPUX) || defined (__UTYPE_BEOS))
return (setgid (get_gid (EFFECTIVE_ID)));
# elif (defined (__OS2__)) /* OS/2 only supports one UID */
return (0);
# elif (defined (__VMS__)) /* No setgid under OpenVMS */
return (0);
# else
return (setegid (get_gid (EFFECTIVE_ID)));
# endif
#else
return (0);
#endif
}
#if (defined (DOES_UID) && !defined (__OS2__) && !defined (__VMS__))
/* -------------------------------------------------------------------------
Function: get_gid -- internal
Synopsis: Returns the real (REAL_ID) or effective (EFFECTIVE_ID) gid.
These values are loaded the first time that the function is called: you
should not rely on the effective gid after changing the gid.
-------------------------------------------------------------------------*/
static gid_t
get_gid (int type)
{
static int
rgid = -1,
egid = -1;
if (rgid == -1)
rgid = getgid ();
if (egid == -1)
# if (defined (__UTYPE_HPUX) || defined (__UTYPE_BEOS))
egid = getgid ();
# else
egid = getegid ();
# endif
if (type == REAL_ID)
return (rgid);
else
if (type == EFFECTIVE_ID)
return (egid);
else
return (0);
}
#endif
/* ---------------------------------------------------------------------[<]-
Function: set_uid_gid
Synopsis: Sets the program's uid and gid to new values as specified
(as names). The program must be currently running as 'root'. Returns
0 if the new names could be correctly used. Returns -1 if the specified
user id or group id was not valid, or -2 if the process was unable to
change to the new uid/gid as specified. The gid may be null or empty.
---------------------------------------------------------------------[>]-*/
int
set_uid_gid (char *new_uid, char *new_gid)
{
#if (defined (DOES_UID))
struct passwd
*pwdbuf;
struct group
*grpbuf;
# if (defined (__VMS__))
return (0);
# else
if (new_gid && *new_gid)
{
if ((grpbuf = getgrnam (new_gid)) == NULL)
return (-1);
else
if (setgid (grpbuf-> gr_gid) == -1)
return (-2);
}
if ((pwdbuf = getpwnam (new_uid)) == NULL)
return (-1);
else
if (setuid (pwdbuf-> pw_uid) == -1)
return (-2);
# endif
#endif
return (0);
}
/* ---------------------------------------------------------------------[<]-
Function: get_login
Synopsis: Returns the identity of the currently-logged user. The
returned string is in a static buffer. Returns NULL if no user is
currently logged-in. Fixed for compilers with broken uuid.lib functions.
---------------------------------------------------------------------[>]-*/
char *
get_login (void)
{
#if (defined (WIN32))
ULONG
user_name_max = 255;
static char
user_name [256];
if (!GetUserNameA (user_name, &user_name_max))
strncpy (user_name, "unknown", sizeof (user_name));
return (user_name);
#elif (defined (__UNIX__) || defined (__OS2__) || defined (__VMS__))
return (getlogin ());
#endif
}
|
