/* FS helper library definitions Copyright (C) 1994, 1995, 1996 Free Software Foundation 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 2, 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; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #ifndef _HURD_FSHELP_ #define _HURD_FSHELP_ /* This library implements various things that are generic to all or most implementors of the filesystem protocol. It presumes that you are using the iohelp library as well. It is divided into separate facilities which may be used independently. */ #include #include #include #include #include #ifndef FSHELP_EI #define FSHELP_EI extern inline #endif /* Passive translator linkage */ /* These routines are self-contained and start passive translators, returning the control port. They do not require multi threading or the ports library. */ /* A callback used by the translator starting functions, which should be a function that given some open flags, opens the appropiate file, and returns the node port. */ typedef error_t (*fshelp_open_fn_t) (int flags, file_t *node, mach_msg_type_name_t *node_type); /* Start a passive translator NAME with arguments ARGZ (length ARGZ_LEN). Initialize the initports to PORTS (length PORTS_LEN), the initints to INTS (length INTS_LEN), and the file descriptor table to FDS (length FDS_LEN). Return the control port in *CONTROL. If the translator doesn't respond or die in TIMEOUT milliseconds (if TIMEOUT > 0), return an appropriate error. If the translator dies before responding, return EDIED. */ error_t fshelp_start_translator_long (fshelp_open_fn_t underlying_open_fn, char *name, char *argz, int argz_len, mach_port_t *fds, mach_msg_type_name_t fds_type, int fds_len, mach_port_t *ports, mach_msg_type_name_t ports_type, int ports_len, int *ints, int ints_len, int timeout, fsys_t *control); /* Same as fshelp_start_translator_long, except the initports and ints are copied from our own state, fd[2] is copied from our own stderr, and the other fds are cleared. */ error_t fshelp_start_translator (fshelp_open_fn_t underlying_open_fn, char *name, char *argz, int argz_len, int timeout, fsys_t *control); /* Active translator linkage */ /* These routines implement the linkage to active translators needed by any filesystem which supports them. They require cthreads and use the passive translator routines above, but they don't require the ports library at all. */ struct transbox { fsys_t active; struct mutex *lock; int flags; struct condition wakeup; void *cookie; }; #define TRANSBOX_STARTING 1 #define TRANSBOX_WANTED 2 /* This interface is complex, because creating the ports and state necessary for start_translator_long is expensive. The caller to fshelp_fetch_root should not need to create them on every call, since usually there will be an existing active translator. */ /* This routine is called by fshelp_fetch_root to fetch more information. Return the owner and group of the underlying translated file in *UID and *GID; point *ARGZ at the entire passive translator spec for the file (setting *ARGZ_LEN to the length.) If there is no passive translator, then return ENOENT. COOKIE1 is the cookie passed in fshelp_transbox_init. COOKIE2 is the cookie passed in the call to fshelp_fetch_root. */ typedef error_t (*fshelp_fetch_root_callback1_t) (void *cookie1, void *cookie2, uid_t *uid, gid_t *gid, char **argz, int *argz_len); /* This routine is called by fshelp_fetch_root to fetch more information. Return an unauthenticated node for the file itself in *UNDERLYING and *UNDERLYING_TYPE (opened with FLAGS). COOKIE1 is the cookie passed in fshelp_transbox_init. COOKIE2 is the cookie passed in the call to fshelp_fetch_root. */ typedef error_t (*fshelp_fetch_root_callback2_t) (void *cookie1, void *cookie2, int flags, mach_port_t *underlying, mach_msg_type_name_t *underlying_type); /* Fetch the root from TRANSBOX. DOTDOT is an unauthenticated port for the directory in which we are looking; USER specifies the ids of the user responsible for the call. FLAGS are as for dir_pathtrans (but O_CREAT and O_EXCL are not meaningful and are ignored). The trasnbox lock (as set by fshelp_transbox_init) must be held before the call, and will be held upon return, but may be released during the operation of the call. */ error_t fshelp_fetch_root (struct transbox *transbox, void *cookie, file_t dotdot, struct iouser *user, int flags, fshelp_fetch_root_callback1_t callback1, fshelp_fetch_root_callback2_t callback2, retry_type *retry, char *retryname, mach_port_t *root); void fshelp_transbox_init (struct transbox *transbox, struct mutex *lock, void *cookie); /* Return true iff there is an active translator on this box */ FSHELP_EI int fshelp_translated (struct transbox *box) { return (box->active != MACH_PORT_NULL); } /* Atomically replace the existing active translator port for this box with NEWACTIVE. If EXCL is non-zero then don't frob an existing active; return EBUSY instead. */ error_t fshelp_set_active (struct transbox *box, fsys_t newactive, int excl); /* Fetch the control port to make a request on it. It's a bad idea to do fsys_getroot with the result; use fetch_root instead. */ error_t fshelp_fetch_control (struct transbox *box, mach_port_t *control); /* A transbox is being deallocated, clean associated state. */ void fshelp_drop_transbox (struct transbox *box); /* Flock handling. */ struct lock_box { int type; struct condition wait; int waiting; int shcount; }; /* Call when a user makes a request to acquire an lock via file_lock. There should be one lock box per object and one int per open; these are passed as arguments BOX and USER respectively. FLAGS are as per file_lock. MUT is a mutex which will be held whenever this routine is called, to lock BOX->wait. */ error_t fshelp_acquire_lock (struct lock_box *box, int *user, struct mutex *mut, int flags); /* Initialize lock_box BOX. (The user int passed to fshelp_acquire_lock should be initialized with LOCK_UN.). */ void fshelp_lock_init (struct lock_box *box); struct port_bucket; /* shut up C compiler */ /* Return an identity port in *PT for the node numbered FILENO, suitable for returning from io_identity; exactly one send right must be created from the returned value. FILENO should be the same value returned as the `fileno' out-parameter in io_identity, and in the enclosing directory (except for mount points), and in the st_ino stat field. BUCKET should be a ports port bucket; fshelp requires the caller to make sure port operations (for no-senders notifications) are used. */ error_t fshelp_get_identity (struct port_bucket *bucket, ino_t fileno, mach_port_t *pt); /* Try to hand off responsibility from a translator to the server located on the node SERVER_NAME. REQUESTOR is the translator's bootstrap port, and ARGV is the command line. If SERVER_NAME is NULL, then a name is concocted by appending ARGV[0] to _SERVERS. */ error_t fshelp_delegate_translation (char *server_name, mach_port_t requestor, char **argv); struct idvec; /* Include to get the real thing. */ /* If SUID or SGID is true, adds UID and/or GID respectively to the authentication in PORTS[INIT_PORT_AUTH], and replaces it with the result. All the other ports in PORTS and FDS are then reauthenticated, using any privileges available through AUTH. If GET_FILE_IDS is non-NULL, and the auth port in PORTS[INIT_PORT_AUTH] is bogus, it is called to get a list of uids and gids from the file to use as a replacement. If SECURE is non-NULL, whether not the added ids are new is returned in it. If either the uid or gid case fails, then the other may still be applied. */ error_t fshelp_exec_reauth (int suid, uid_t uid, int sgid, gid_t gid, auth_t auth, error_t (*get_file_ids)(struct idvec *uids, struct idvec *gids), mach_port_t *ports, mach_msg_type_number_t num_ports, mach_port_t *fds, mach_msg_type_number_t num_fds, int *secure); struct argp; /* Include to get the real thing. */ /* Invoke ARGP with data from DATA & LEN, in the standard way. */ error_t fshelp_set_options (struct argp *argp, int flags, char *argz, size_t argz_len, void *input); /* Puts data from the malloced buffer BUF, LEN bytes long, into RBUF & RLEN, suitable for returning from a mach rpc. If LEN > 0, BUF is freed, regardless of whether an error is returned or not. */ error_t fshelp_return_malloced_buffer (char *buf, size_t len, char **rbuf, mach_msg_type_number_t *rlen); /* Standardized filesystem permission checking */ /* Check to see whether USER should be considered the owner of the file identified by ST. If so, return zero; otherwise return an appropriate error code. */ FSHELP_EI error_t fshelp_isowner (struct stat *st, struct iouser *user) { /* Permitted if the user has the owner UID, the superuser UID, or if the user is in the group of the file and has the group ID as their user ID. */ if (idvec_contains (user->uids, st->st_uid) || idvec_contains (user->uids, 0) || (idvec_contains (user->gids, st->st_gid) && idvec_contains (user->uids, st->st_gid))) return 0; else return EPERM; } /* Check to see whether the user USER can operate on a file identified by ST. OP is one of S_IREAD, S_IWRITE, and S_IEXEC. If the access is permitted, return zero; otherwise return an appropriate error code. */ FSHELP_EI error_t fshelp_access (struct stat *st, int op, struct iouser *user) { if (idvec_contains (user->uids, 0)) gotit = 1; else if (user->uids->num == 0 && (st->st_mode & S_IUSEUNK)) gotit = st->st_mode & (op << S_IUSEUNKSHIFT); else if (!fshelp_isowner (st, user)) gotit = st->st_mode & op; else if (idvec_contains (user->gids, st->st_gid)) gotit = st->st_mode & (op >> 3); else gotit = st->st_mode & (op >> 6); return gotit ? 0 : EACCES; } /* Check to see whether USER is allowed to modify DIR with respect to existing file ST. (If there is no existing file, pass 0 for ST.) If the access is permissable return 0; otherwise return an appropriate error code. */ FSHELP_EI error_t fshelp_checkdirmod (struct stat *dir, struct stat *st, struct iouser *user) { error_t err; /* The user must be able to write the directory. */ err = fshelp_access (dir, S_IWRITE, user); if (err) return err; /* If the directory is sticky, the user must own either it or the file. */ if ((dir->st_mode & S_ISVTX) && st && fshelp_isowner (dir, user) && fshelp_isowner (st, user)) return EACCES; return 0; } #endif