diff options
Diffstat (limited to 'winsup/cygwin/cygserver_shm.cc')
| -rwxr-xr-x | winsup/cygwin/cygserver_shm.cc | 896 |
1 files changed, 896 insertions, 0 deletions
diff --git a/winsup/cygwin/cygserver_shm.cc b/winsup/cygwin/cygserver_shm.cc new file mode 100755 index 000000000..90053eec2 --- /dev/null +++ b/winsup/cygwin/cygserver_shm.cc @@ -0,0 +1,896 @@ +/* cygserver_shm.cc: Single unix specification IPC interface for Cygwin. + + Copyright 2002 Red Hat, Inc. + + Written by Conrad Scott <conrad.scott@dsl.pipex.com>. + Based on code by Robert Collins <robert.collins@hotmail.com>. + +This file is part of Cygwin. + +This software is a copyrighted work licensed under the terms of the +Cygwin license. Please consult the file "CYGWIN_LICENSE" for +details. */ + +#include "woutsup.h" + +#include <errno.h> +#include <pthread.h> +#include <stdio.h> +#include <string.h> +#include <time.h> + +#include "cygserver_ipc.h" +#include "cygserver_shm.h" +#include "security.h" + +#include "cygwin/cygserver.h" +#include "cygwin/cygserver_process.h" +#include "cygwin/cygserver_transport.h" + +/*---------------------------------------------------------------------------* + * class server_shmmgr + * + * A singleton class. + *---------------------------------------------------------------------------*/ + +#define shmmgr (server_shmmgr::instance ()) + +class server_shmmgr +{ +private: + class attach_t + { + public: + class process *const _client; + unsigned int _refcnt; + + attach_t *_next; + + attach_t (class process *const client) + : _client (client), + _refcnt (0), + _next (NULL) + {} + }; + + class segment_t + { + private: + // Bits for the _flg field. + enum { IS_DELETED = 0x01 }; + + public: + const int _intid; + const int _shmid; + struct shmid_ds _ds; + + segment_t *_next; + + segment_t (const key_t key, const int intid, const HANDLE hFileMap); + ~segment_t (); + + bool is_deleted () const + { + return _flg & IS_DELETED; + } + + bool is_pending_delete () const + { + return !_ds.shm_nattch && is_deleted (); + } + + void mark_deleted () + { + assert (!is_deleted ()); + + _flg |= IS_DELETED; + } + + int attach (class process *, HANDLE & hFileMap); + int detach (class process *); + + private: + static long _sequence; + + int _flg; + const HANDLE _hFileMap; + attach_t *_attach_head; // A list sorted by winpid; + + attach_t *find (const class process *, attach_t **previous = NULL); + }; + + class cleanup_t : public cleanup_routine + { + public: + cleanup_t (const segment_t *const segptr) + : cleanup_routine (reinterpret_cast<void *> (segptr->_shmid)) + { + assert (key ()); + } + + int shmid () const { return reinterpret_cast<int> (key ()); } + + virtual void cleanup (class process *const client) + { + const int res = shmmgr.shmdt (shmid (), client); + + if (res != 0) + debug_printf ("process cleanup failed [shmid = %d]: %s", + shmid (), strerror (-res)); + } + }; + +public: + static server_shmmgr & instance (); + + int shmat (HANDLE & hFileMap, + int shmid, int shmflg, class process *); + int shmctl (int & out_shmid, struct shmid_ds & out_ds, + struct shminfo & out_shminfo, struct shm_info & out_shm_info, + const int shmid, int cmd, const struct shmid_ds &, + class process *); + int shmdt (int shmid, class process *); + int shmget (int & out_shmid, key_t, size_t, int shmflg, uid_t, gid_t, + class process *); + +private: + static server_shmmgr *_instance; + static pthread_once_t _instance_once; + + static void initialise_instance (); + + CRITICAL_SECTION _segments_lock; + segment_t *_segments_head; // A list sorted by int_id. + + int _shm_ids; // Number of shm segments (for ipcs(8)). + int _shm_tot; // Total bytes of shm segments (for ipcs(8)). + int _shm_atts; // Number of attached segments (for ipcs(8)). + int _intid_max; // Highest intid yet allocated (for ipcs(8)). + + server_shmmgr (); + ~server_shmmgr (); + + // Undefined (as this class is a singleton): + server_shmmgr (const server_shmmgr &); + server_shmmgr & operator= (const server_shmmgr &); + + segment_t *find_by_key (key_t); + segment_t *find (int intid, segment_t **previous = NULL); + + int new_segment (key_t, size_t, int shmflg, pid_t, uid_t, gid_t); + + segment_t *new_segment (key_t, size_t, HANDLE); + void delete_segment (segment_t *); +}; + +/* static */ long server_shmmgr::segment_t::_sequence = 0; + +/* static */ server_shmmgr *server_shmmgr::_instance = NULL; +/* static */ pthread_once_t server_shmmgr::_instance_once = PTHREAD_ONCE_INIT; + +/*---------------------------------------------------------------------------* + * server_shmmgr::segment_t::segment_t () + *---------------------------------------------------------------------------*/ + +server_shmmgr::segment_t::segment_t (const key_t key, + const int intid, + const HANDLE hFileMap) + : _intid (intid), + _shmid (ipc_int2ext (intid, IPC_SHMOP, _sequence)), + _next (NULL), + _flg (0), + _hFileMap (hFileMap), + _attach_head (NULL) +{ + assert (0 <= _intid && _intid < SHMMNI); + + memset (&_ds, '\0', sizeof (_ds)); + _ds.shm_perm.key = key; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::segment_t::~segment_t () + *---------------------------------------------------------------------------*/ + +server_shmmgr::segment_t::~segment_t () +{ + assert (!_attach_head); + + if (!CloseHandle (_hFileMap)) + syscall_printf ("failed to close file map [handle = 0x%x]: %E", _hFileMap); +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::segment_t::attach () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::segment_t::attach (class process *const client, + HANDLE & hFileMap) +{ + assert (client); + + if (!DuplicateHandle (GetCurrentProcess (), + _hFileMap, + client->handle (), + &hFileMap, + 0, + FALSE, // bInheritHandle + DUPLICATE_SAME_ACCESS)) + { + syscall_printf (("failed to duplicate handle for client " + "[key = 0x%016llx, shmid = %d, handle = 0x%x]: %E"), + _ds.shm_perm.key, _shmid, _hFileMap); + + return -EACCES; // FIXME: Case analysis? + } + + _ds.shm_lpid = client->cygpid (); + _ds.shm_nattch += 1; + _ds.shm_atime = time (NULL); // FIXME: sub-second times. + + attach_t *previous = NULL; + attach_t *attptr = find (client, &previous); + + if (!attptr) + { + attptr = safe_new (attach_t, client); + + if (previous) + { + attptr->_next = previous->_next; + previous->_next = attptr; + } + else + { + attptr->_next = _attach_head; + _attach_head = attptr; + } + } + + attptr->_refcnt += 1; + + cleanup_t *const cleanup = safe_new (cleanup_t, this); + + // FIXME: ::add should only fail if the process object is already + // cleaning up; but it can't be doing that since this thread has it + // locked. + + const bool result = client->add (cleanup); + + assert (result); + + return 0; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::segment_t::detach () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::segment_t::detach (class process *const client) +{ + attach_t *previous = NULL; + attach_t *const attptr = find (client, &previous); + + if (!attptr) + return -EINVAL; + + if (client->is_active ()) + { + const cleanup_t key (this); + + if (!client->remove (&key)) + syscall_printf (("failed to remove cleanup routine for %d(%lu) " + "[shmid = %d]"), + client->cygpid (), client->winpid (), + _shmid); + } + + attptr->_refcnt -= 1; + + if (!attptr->_refcnt) + { + assert (previous ? previous->_next == attptr : _attach_head == attptr); + + if (previous) + previous->_next = attptr->_next; + else + _attach_head = attptr->_next; + + safe_delete (attptr); + } + + assert (_ds.shm_nattch > 0); + + _ds.shm_lpid = client->cygpid (); + _ds.shm_nattch -= 1; + _ds.shm_dtime = time (NULL); // FIXME: sub-second times. + + return 0; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::segment_t::find () + *---------------------------------------------------------------------------*/ + +server_shmmgr::attach_t * +server_shmmgr::segment_t::find (const class process *const client, + attach_t **previous) +{ + if (previous) + *previous = NULL; + + // Nb. The _attach_head list is sorted by winpid. + + for (attach_t *attptr = _attach_head; attptr; attptr = attptr->_next) + if (attptr->_client == client) + return attptr; + else if (attptr->_client->winpid () > client->winpid ()) + return NULL; + else if (previous) + *previous = attptr; + + return NULL; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::instance () + *---------------------------------------------------------------------------*/ + +/* static */ server_shmmgr & +server_shmmgr::instance () +{ + pthread_once (&_instance_once, &initialise_instance); + + assert (_instance); + + return *_instance; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::shmat () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::shmat (HANDLE & hFileMap, + const int shmid, const int shmflg, + class process *const client) +{ + syscall_printf ("shmat (shmid = %d, shmflg = 0%o) for %d(%lu)", + shmid, shmflg, client->cygpid (), client->winpid ()); + + int result = 0; + EnterCriticalSection (&_segments_lock); + + segment_t *const segptr = find (ipc_ext2int (shmid, IPC_SHMOP)); + + if (!segptr) + result = -EINVAL; + else + result = segptr->attach (client, hFileMap); + + if (!result) + _shm_atts += 1; + + LeaveCriticalSection (&_segments_lock); + + if (result < 0) + syscall_printf (("-1 [%d] = shmat (shmid = %d, shmflg = 0%o) " + "for %d(%lu)"), + -result, shmid, shmflg, + client->cygpid (), client->winpid ()); + else + syscall_printf (("0x%x = shmat (shmid = %d, shmflg = 0%o) " + "for %d(%lu)"), + hFileMap, shmid, shmflg, + client->cygpid (), client->winpid ()); + + return result; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::shmctl () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::shmctl (int & out_shmid, + struct shmid_ds & out_ds, + struct shminfo & out_shminfo, + struct shm_info & out_shm_info, + const int shmid, const int cmd, + const struct shmid_ds & ds, + class process *const client) +{ + syscall_printf ("shmctl (shmid = %d, cmd = 0x%x) for %d(%lu)", + shmid, cmd, client->cygpid (), client->winpid ()); + + int result = 0; + EnterCriticalSection (&_segments_lock); + + switch (cmd) + { + case IPC_STAT: + case SHM_STAT: // Uses intids rather than shmids. + case IPC_SET: + case IPC_RMID: + { + int intid; + + if (cmd == SHM_STAT) + intid = shmid; + else + intid = ipc_ext2int (shmid, IPC_SHMOP); + + segment_t *const segptr = find (intid); + + if (!segptr) + result = -EINVAL; + else + switch (cmd) + { + case IPC_STAT: + out_ds = segptr->_ds; + break; + + case IPC_SET: + segptr->_ds.shm_perm.uid = ds.shm_perm.uid; + segptr->_ds.shm_perm.gid = ds.shm_perm.gid; + segptr->_ds.shm_perm.mode = ds.shm_perm.mode & 0777; + segptr->_ds.shm_lpid = client->cygpid (); + segptr->_ds.shm_ctime = time (NULL); // FIXME: sub-second times. + break; + + case IPC_RMID: + if (segptr->is_deleted ()) + result = -EIDRM; + else + { + segptr->mark_deleted (); + if (segptr->is_pending_delete ()) + delete_segment (segptr); + } + break; + + case SHM_STAT: // ipcs(8) i'face. + out_ds = segptr->_ds; + out_shmid = segptr->_shmid; + break; + } + } + break; + + case IPC_INFO: + out_shminfo.shmmax = SHMMAX; + out_shminfo.shmmin = SHMMIN; + out_shminfo.shmmni = SHMMNI; + out_shminfo.shmseg = SHMSEG; + out_shminfo.shmall = SHMALL; + break; + + case SHM_INFO: // ipcs(8) i'face. + out_shmid = _intid_max; + out_shm_info.shm_ids = _shm_ids; + out_shm_info.shm_tot = _shm_tot; + out_shm_info.shm_atts = _shm_atts; + break; + + default: + result = -EINVAL; + break; + } + + LeaveCriticalSection (&_segments_lock); + + if (result < 0) + syscall_printf (("-1 [%d] = " + "shmctl (shmid = %d, cmd = 0x%x) for %d(%lu)"), + -result, + shmid, cmd, client->cygpid (), client->winpid ()); + else + syscall_printf (("%d = " + "shmctl (shmid = %d, cmd = 0x%x) for %d(%lu)"), + ((cmd == SHM_STAT || cmd == SHM_INFO) + ? out_shmid + : result), + shmid, cmd, client->cygpid (), client->winpid ()); + + return result; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::shmdt () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::shmdt (const int shmid, class process *const client) +{ + syscall_printf ("shmdt (shmid = %d) for %d(%lu)", + shmid, client->cygpid (), client->winpid ()); + + int result = 0; + EnterCriticalSection (&_segments_lock); + + segment_t *const segptr = find (ipc_ext2int (shmid, IPC_SHMOP)); + + if (!segptr) + result = -EINVAL; + else + result = segptr->detach (client); + + if (!result) + _shm_atts -= 1; + + if (!result && segptr->is_pending_delete ()) + delete_segment (segptr); + + LeaveCriticalSection (&_segments_lock); + + if (result < 0) + syscall_printf ("-1 [%d] = shmdt (shmid = %d) for %d(%lu)", + -result, shmid, client->cygpid (), client->winpid ()); + else + syscall_printf ("%d = shmdt (shmid = %d) for %d(%lu)", + result, shmid, client->cygpid (), client->winpid ()); + + return result; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::shmget () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::shmget (int & out_shmid, + const key_t key, const size_t size, const int shmflg, + const uid_t uid, const gid_t gid, + class process *const client) +{ + syscall_printf (("shmget (key = 0x%016llx, size = %u, shmflg = 0%o) " + "for %d(%lu)"), + key, size, shmflg, + client->cygpid (), client->winpid ()); + + int result = 0; + EnterCriticalSection (&_segments_lock); + + if (key == IPC_PRIVATE) + result = new_segment (key, size, shmflg, + client->cygpid (), uid, gid); + else + { + segment_t *const segptr = find_by_key (key); + + if (!segptr) + if (shmflg & IPC_CREAT) + result = new_segment (key, size, shmflg, + client->cygpid (), uid, gid); + else + result = -ENOENT; + else if (segptr->is_deleted ()) + result = -EIDRM; + else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) + result = -EEXIST; + else if ((shmflg & ~(segptr->_ds.shm_perm.mode)) & 0777) + result = -EACCES; + else if (size && segptr->_ds.shm_segsz < size) + result = -EINVAL; + else + result = segptr->_shmid; + } + + LeaveCriticalSection (&_segments_lock); + + if (result >= 0) + { + out_shmid = result; + result = 0; + } + + if (result < 0) + syscall_printf (("-1 [%d] = " + "shmget (key = 0x%016llx, size = %u, shmflg = 0%o) " + "for %d(%lu)"), + -result, + key, size, shmflg, + client->cygpid (), client->winpid ()); + else + syscall_printf (("%d = " + "shmget (key = 0x%016llx, size = %u, shmflg = 0%o) " + "for %d(%lu)"), + out_shmid, + key, size, shmflg, + client->cygpid (), client->winpid ()); + + return result; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::initialise_instance () + *---------------------------------------------------------------------------*/ + +/* static */ void +server_shmmgr::initialise_instance () +{ + assert (!_instance); + + _instance = safe_new0 (server_shmmgr); + + assert (_instance); +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::server_shmmgr () + *---------------------------------------------------------------------------*/ + +server_shmmgr::server_shmmgr () + : _segments_head (NULL), + _shm_ids (0), + _shm_tot (0), + _shm_atts (0), + _intid_max (0) +{ + InitializeCriticalSection (&_segments_lock); +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::~server_shmmgr () + *---------------------------------------------------------------------------*/ + +server_shmmgr::~server_shmmgr () +{ + DeleteCriticalSection (&_segments_lock); +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::find_by_key () + *---------------------------------------------------------------------------*/ + +server_shmmgr::segment_t * +server_shmmgr::find_by_key (const key_t key) +{ + for (segment_t *segptr = _segments_head; segptr; segptr = segptr->_next) + if (segptr->_ds.shm_perm.key == key) + return segptr; + + return NULL; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::find () + *---------------------------------------------------------------------------*/ + +server_shmmgr::segment_t * +server_shmmgr::find (const int intid, segment_t **previous) +{ + if (previous) + *previous = NULL; + + for (segment_t *segptr = _segments_head; segptr; segptr = segptr->_next) + if (segptr->_intid == intid) + return segptr; + else if (segptr->_intid > intid) // The list is sorted by intid. + return NULL; + else if (previous) + *previous = segptr; + + return NULL; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::new_segment () + *---------------------------------------------------------------------------*/ + +int +server_shmmgr::new_segment (const key_t key, + const size_t size, + const int shmflg, + const pid_t cygpid, + const uid_t uid, + const gid_t gid) +{ + if (size < SHMMIN || size > SHMMAX) + return -EINVAL; + + const HANDLE hFileMap = CreateFileMapping (INVALID_HANDLE_VALUE, + NULL, PAGE_READWRITE, + 0, size, + NULL); + + if (!hFileMap) + { + syscall_printf ("failed to create file mapping [size = %lu]: %E", size); + return -ENOMEM; // FIXME + } + + segment_t *const segptr = new_segment (key, size, hFileMap); + + if (!segptr) + { + (void) CloseHandle (hFileMap); + return -ENOSPC; + } + + segptr->_ds.shm_perm.cuid = segptr->_ds.shm_perm.uid = uid; + segptr->_ds.shm_perm.cgid = segptr->_ds.shm_perm.gid = gid; + segptr->_ds.shm_perm.mode = shmflg & 0777; + segptr->_ds.shm_segsz = size; + segptr->_ds.shm_cpid = cygpid; + segptr->_ds.shm_ctime = time (NULL); // FIXME: sub-second times. + + return segptr->_shmid; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::new_segment () + * + * Allocate a new segment for the given key and file map with the + * lowest available intid and insert into the segment map. + *---------------------------------------------------------------------------*/ + +server_shmmgr::segment_t * +server_shmmgr::new_segment (const key_t key, const size_t size, + const HANDLE hFileMap) +{ + // FIXME: Overflow risk. + if (_shm_tot + size > SHMALL) + return NULL; + + int intid = 0; // Next expected intid value. + segment_t *previous = NULL; // Insert pointer. + + // Find first unallocated intid. + for (segment_t *segptr = _segments_head; + segptr && segptr->_intid == intid; + segptr = segptr->_next, intid++) + { + previous = segptr; + } + + /* By the time this condition is reached (given the default value of + * SHMMNI), the linear searches should all replaced by something + * just a *little* cleverer . . . + */ + if (intid >= SHMMNI) + return NULL; + + segment_t *const segptr = safe_new (segment_t, key, intid, hFileMap); + + assert (segptr); + + if (previous) + { + segptr->_next = previous->_next; + previous->_next = segptr; + } + else + { + segptr->_next = _segments_head; + _segments_head = segptr; + } + + _shm_ids += 1; + _shm_tot += size; + if (intid > _intid_max) + _intid_max = intid; + + return segptr; +} + +/*---------------------------------------------------------------------------* + * server_shmmgr::delete_segment () + *---------------------------------------------------------------------------*/ + +void +server_shmmgr::delete_segment (segment_t *const segptr) +{ + assert (segptr); + assert (segptr->is_pending_delete ()); + + segment_t *previous = NULL; + + const segment_t *const tmp = find (segptr->_intid, &previous); + + assert (tmp == segptr); + assert (previous ? previous->_next == segptr : _segments_head == segptr); + + if (previous) + previous->_next = segptr->_next; + else + _segments_head = segptr->_next; + + assert (_shm_ids > 0); + _shm_ids -= 1; + _shm_tot -= segptr->_ds.shm_segsz; + + safe_delete (segptr); +} + +/*---------------------------------------------------------------------------* + * client_request_shm::client_request_shm () + *---------------------------------------------------------------------------*/ + +client_request_shm::client_request_shm () + : client_request (CYGSERVER_REQUEST_SHM, + &_parameters, sizeof (_parameters)) +{ + // verbose: syscall_printf ("created"); +} + +/*---------------------------------------------------------------------------* + * client_request_shm::serve () + *---------------------------------------------------------------------------*/ + +void +client_request_shm::serve (transport_layer_base *const conn, + process_cache *const cache) +{ + assert (conn); + + assert (!error_code ()); + + if (msglen () != sizeof (_parameters.in)) + { + syscall_printf ("bad request body length: expecting %lu bytes, got %lu", + sizeof (_parameters), msglen ()); + error_code (EINVAL); + msglen (0); + return; + } + + // FIXME: Get a return code out of this and don't continue on error. + conn->impersonate_client (); + + class process *const client = cache->process (_parameters.in.cygpid, + _parameters.in.winpid); + + if (!client) + { + error_code (EAGAIN); + msglen (0); + return; + } + + int result = -EINVAL; + + switch (_parameters.in.shmop) + { + case SHMOP_shmget: + result = shmmgr.shmget (_parameters.out.shmid, + _parameters.in.key, _parameters.in.size, + _parameters.in.shmflg, + _parameters.in.uid, _parameters.in.gid, + client); + break; + + case SHMOP_shmat: + result = shmmgr.shmat (_parameters.out.hFileMap, + _parameters.in.shmid, _parameters.in.shmflg, + client); + break; + + case SHMOP_shmdt: + result = shmmgr.shmdt (_parameters.in.shmid, client); + break; + + case SHMOP_shmctl: + result = shmmgr.shmctl (_parameters.out.shmid, + _parameters.out.ds, _parameters.out.shminfo, + _parameters.out.shm_info, + _parameters.in.shmid, _parameters.in.cmd, + _parameters.in.ds, + client); + break; + } + + client->release (); + conn->revert_to_self (); + + if (result < 0) + { + error_code (-result); + msglen (0); + } + else + msglen (sizeof (_parameters.out)); +} |