181 lines
4.1 KiB
C
181 lines
4.1 KiB
C
/* userspec.c -- Parse a user and group string.
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Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
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/* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
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#include <stdio.h>
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#include <sys/types.h>
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#include <pwd.h>
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#include <grp.h>
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#if defined(STDC_HEADERS) || defined(HAVE_STRING_H)
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#include <string.h>
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#ifndef index
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#define index strchr
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#endif
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#else
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#include <strings.h>
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#endif
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#ifdef STDC_HEADERS
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#include <stdlib.h>
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#else
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char *malloc ();
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifndef _POSIX_VERSION
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struct passwd *getpwnam ();
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struct group *getgrnam ();
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struct group *getgrgid ();
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#endif
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#ifdef _POSIX_SOURCE
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#define endpwent()
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#define endgrent()
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#endif
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#define isdigit(c) ((c) >= '0' && (c) <= '9')
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char *strdup ();
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static int isnumber ();
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/* Extract from NAME, which has the form "[user][:.][group]",
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a USERNAME, UID U, GROUPNAME, and GID G.
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Either user or group, or both, must be present.
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If the group is omitted but the ":" or "." separator is given,
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use the given user's login group.
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USERNAME and GROUPNAME will be in newly malloc'd memory.
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Either one might be NULL instead, indicating that it was not
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given and the corresponding numeric ID was left unchanged.
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Might write NULs into NAME.
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Return NULL if successful, a static error message string if not. */
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char *
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parse_user_spec (name, uid, gid, username, groupname)
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char *name;
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uid_t *uid;
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gid_t *gid;
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char **username, **groupname;
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{
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static char *tired = "virtual memory exhausted";
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struct passwd *pwd;
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struct group *grp;
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char *cp;
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int use_login_group = 0;
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*username = *groupname = NULL;
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/* Check whether a group is given. */
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cp = index (name, ':');
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if (cp == NULL)
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cp = index (name, '.');
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if (cp != NULL)
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{
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*cp++ = '\0';
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if (*cp == '\0')
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{
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if (cp == name + 1)
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/* Neither user nor group given, just "." or ":". */
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return "can not omit both user and group";
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else
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/* "user.". */
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use_login_group = 1;
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}
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else
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{
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/* Explicit group. */
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*groupname = strdup (cp);
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if (*groupname == NULL)
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return tired;
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grp = getgrnam (cp);
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if (grp == NULL)
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{
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if (!isnumber (cp))
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return "invalid group";
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*gid = atoi (cp);
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}
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else
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*gid = grp->gr_gid;
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endgrent (); /* Save a file descriptor. */
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}
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}
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/* Parse the user name, now that any group has been removed. */
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if (name[0] == '\0')
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/* No user name was given, just a group. */
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return NULL;
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*username = strdup (name);
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if (*username == NULL)
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return tired;
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pwd = getpwnam (name);
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if (pwd == NULL)
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{
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if (!isnumber (name))
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return "invalid user";
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if (use_login_group)
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return "cannot get the login group of a numeric UID";
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*uid = atoi (name);
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}
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else
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{
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*uid = pwd->pw_uid;
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if (use_login_group)
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{
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*gid = pwd->pw_gid;
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grp = getgrgid (pwd->pw_gid);
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if (grp == NULL)
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{
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*groupname = malloc (15);
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if (*groupname == NULL)
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return tired;
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sprintf (*groupname, "%u", pwd->pw_gid);
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}
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else
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{
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*groupname = strdup (grp->gr_name);
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if (*groupname == NULL)
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return tired;
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}
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endgrent ();
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}
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}
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endpwent ();
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return NULL;
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}
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/* Return nonzero if STR represents an unsigned decimal integer,
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otherwise return 0. */
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static int
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isnumber (str)
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char *str;
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{
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for (; *str; str++)
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if (!isdigit (*str))
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return 0;
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return 1;
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}
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