diff options
Diffstat (limited to 'winsup/cygserver/sysv_sem.cc')
-rw-r--r-- | winsup/cygserver/sysv_sem.cc | 1323 |
1 files changed, 1323 insertions, 0 deletions
diff --git a/winsup/cygserver/sysv_sem.cc b/winsup/cygserver/sysv_sem.cc new file mode 100644 index 000000000..ac5efcdaa --- /dev/null +++ b/winsup/cygserver/sysv_sem.cc @@ -0,0 +1,1323 @@ +/* + * Implementation of SVID semaphores + * + * Author: Daniel Boulet + * + * This software is provided ``AS IS'' without any warranties of any kind. + */ + +/* + * This file is heavily changed to become part of Cygwin's cygserver. + */ + +#ifdef __OUTSIDE_CYGWIN__ +#include "woutsup.h" +#include <sys/cygwin.h> +#include <sys/cdefs.h> +#ifndef __FBSDID +#define __FBSDID(s) const char version[] = (s) +#endif +__FBSDID("$FreeBSD: /usr/local/www/cvsroot/FreeBSD/src/sys/kern/sysv_sem.c,v 1.66 2003/11/10 07:22:41 tjr Exp $"); + +#define _KERNEL 1 +#define __BSD_VISIBLE 1 +#include <sys/types.h> +#include <sys/ipc.h> + +#include <sys/param.h> +#include <sys/sysproto.h> +#include <sys/lock.h> +#include <sys/sem.h> +#include <sys/queue.h> +#include <malloc.h> +#include <errno.h> +#include <time.h> +#include "cygserver.h" +#include "process.h" +#include "cygserver_ipc.h" + +#ifdef __CYGWIN__ +#define __semctl semctl +#define __semctl_args semctl_args +#define SEM_DEBUG +#endif /* __CYGWIN__ */ + +#ifdef SEM_DEBUG +#define DPRINTF(a) debug_printf a +#else +#define DPRINTF(a) +#endif + +static int semvalid(int semid, struct semid_ds *semaptr); + +static struct sem_undo *semu_alloc(struct thread *td); +static int semundo_adjust(struct thread *td, struct sem_undo **supptr, + int semid, int semnum, int adjval); +static void semundo_clear(int semid, int semnum); + +#ifndef _SYS_SYSPROTO_H_ +struct __semctl_args; +int __semctl(struct thread *td, struct __semctl_args *uap); +struct semget_args; +int semget(struct thread *td, struct semget_args *uap); +struct semop_args; +int semop(struct thread *td, struct semop_args *uap); +#endif + +#ifndef __CYGWIN__ +/* XXX casting to (sy_call_t *) is bogus, as usual. */ +static sy_call_t *semcalls[] = { + (sy_call_t *)__semctl, (sy_call_t *)semget, + (sy_call_t *)semop +}; +#endif + +static struct mtx sem_mtx; /* semaphore global lock */ +static int semtots = 0; +static int semtot = 0; +static struct semid_ds *sema; /* semaphore id pool */ +static struct mtx *sema_mtx; /* semaphore id pool mutexes*/ +static struct sem *sem; /* semaphore pool */ +SLIST_HEAD(, sem_undo) semu_list; /* list of active undo structures */ +static int *semu; /* undo structure pool */ +#ifndef __CYGWIN__ +static eventhandler_tag semexit_tag; +#endif /* __CYGWIN__ */ + +#define SEMUNDO_MTX sem_mtx +#define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX); +#define SEMUNDO_HOOKLOCK() _mtx_lock(&SEMUNDO_MTX, p->winpid, __FILE__, __LINE__); +#define SEMUNDO_UNLOCK() mtx_unlock(&SEMUNDO_MTX); +#define SEMUNDO_LOCKASSERT(how) mtx_assert(&SEMUNDO_MTX, (how)); + +struct sem { + u_short semval; /* semaphore value */ + pid_t sempid; /* pid of last operation */ + u_short semncnt; /* # awaiting semval > cval */ + u_short semzcnt; /* # awaiting semval = 0 */ +}; + +/* + * Undo structure (one per process) + */ +struct undo { + short un_adjval; /* adjust on exit values */ + short un_num; /* semaphore # */ + int un_id; /* semid */ +} un_ent[1]; /* undo entries */ + +struct sem_undo { + SLIST_ENTRY(sem_undo) un_next; /* ptr to next active undo structure */ + struct proc *un_proc; /* owner of this structure */ + short un_cnt; /* # of active entries */ + struct undo un_ent[1]; /* undo entries */ +}; + +/* + * Configuration parameters + */ +#ifndef SEMMNI +#define SEMMNI 10 /* # of semaphore identifiers */ +#endif +#ifndef SEMMNS +#define SEMMNS 60 /* # of semaphores in system */ +#endif +#ifndef SEMUME +#define SEMUME 10 /* max # of undo entries per process */ +#endif +#ifndef SEMMNU +#define SEMMNU 30 /* # of undo structures in system */ +#endif + +/* shouldn't need tuning */ +#ifndef SEMMAP +#define SEMMAP 30 /* # of entries in semaphore map */ +#endif +#ifndef SEMMSL +#define SEMMSL SEMMNS /* max # of semaphores per id */ +#endif +#ifndef SEMOPM +#define SEMOPM 100 /* max # of operations per semop call */ +#endif + +#ifndef SEMVMX +#define SEMVMX 32767 /* semaphore maximum value */ +#endif +#ifndef SEMAEM +#define SEMAEM 16384 /* adjust on exit max value */ +#endif + +/* + * Due to the way semaphore memory is allocated, we have to ensure that + * SEMUSZ is properly aligned. + */ + +#define SEM_ALIGN(bytes) (((bytes) + (sizeof(long) - 1)) & ~(sizeof(long) - 1)) + +/* actual size of an undo structure */ +#define SEMUSZ SEM_ALIGN(offsetof(struct sem_undo, un_ent[SEMUME])) + +/* + * Macro to find a particular sem_undo vector + */ +#define SEMU(ix) \ + ((struct sem_undo *)(((intptr_t)semu)+ix * seminfo.semusz)) + +/* + * semaphore info struct + */ +struct seminfo seminfo = { + SEMMNI, /* # of semaphore identifiers */ + SEMMNS, /* # of semaphores in system */ + SEMMSL, /* max # of semaphores per id */ + SEMOPM, /* max # of operations per semop call */ + SEMMNU, /* # of undo structures in system */ + SEMUME, /* max # of undo entries per process */ + SEMVMX, /* semaphore maximum value */ + SEMAEM, /* adjust on exit max value */ + SEMMAP, /* # of entries in semaphore map */ + SEMUSZ /* size in bytes of undo structure */ +}; + +#ifndef __CYGWIN__ +SYSCTL_DECL(_kern_ipc); +SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RDTUN, &seminfo.semmni, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RDTUN, &seminfo.semmns, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RDTUN, &seminfo.semmnu, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RDTUN, &seminfo.semopm, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RDTUN, &seminfo.semume, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RDTUN, &seminfo.semusz, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx, CTLFLAG_RW, &seminfo.semvmx, 0, ""); +SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RW, &seminfo.semaem, 0, ""); +SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLFLAG_RD, + NULL, 0, sysctl_sema, "", ""); +#endif /* __CYGWIN__ */ + +void +seminit(void) +{ + int i; + + TUNABLE_INT_FETCH("kern.ipc.semmap", &seminfo.semmap); + TUNABLE_INT_FETCH("kern.ipc.semmni", &seminfo.semmni); + TUNABLE_INT_FETCH("kern.ipc.semmns", &seminfo.semmns); + TUNABLE_INT_FETCH("kern.ipc.semmnu", &seminfo.semmnu); + TUNABLE_INT_FETCH("kern.ipc.semmsl", &seminfo.semmsl); + TUNABLE_INT_FETCH("kern.ipc.semopm", &seminfo.semopm); + TUNABLE_INT_FETCH("kern.ipc.semume", &seminfo.semume); + TUNABLE_INT_FETCH("kern.ipc.semusz", &seminfo.semusz); + TUNABLE_INT_FETCH("kern.ipc.semvmx", &seminfo.semvmx); + TUNABLE_INT_FETCH("kern.ipc.semaem", &seminfo.semaem); + +#ifdef __CYGWIN__ + /* It's too dangerous a setting to leave it alone. + Keep that clean here. */ + seminfo.semusz = SEM_ALIGN(offsetof(struct sem_undo, + un_ent[seminfo.semume])); +#endif /* __CYGWIN__ */ + + sem = (struct sem *) sys_malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK); + sema = (struct semid_ds *) sys_malloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM, + M_WAITOK); + sema_mtx = (struct mtx *) sys_malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM, + M_WAITOK | M_ZERO); + semu = (int *) sys_malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK); + + for (i = 0; i < seminfo.semmni; i++) { + sema[i].sem_base = 0; + sema[i].sem_perm.mode = 0; + } + for (i = 0; i < seminfo.semmni; i++) + mtx_init(&sema_mtx[i], "semid", NULL, MTX_DEF); + for (i = 0; i < seminfo.semmnu; i++) { + struct sem_undo *suptr = SEMU(i); + suptr->un_proc = NULL; + } + SLIST_INIT(&semu_list); + mtx_init(&sem_mtx, "sem", NULL, MTX_DEF); +#ifndef __CYGWIN__ + semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL, + EVENTHANDLER_PRI_ANY); +#endif /* __CYGWIN__ */ +} + +int +semunload(void) +{ +#ifndef __CYGWIN__ /* Would result in being unable to shutdown the + server gracefully. */ + if (semtot != 0) + return (EBUSY); + + EVENTHANDLER_DEREGISTER(process_exit, semexit_tag); +#endif /* __CYGWIN__ */ + sys_free(sem, M_SEM); + sys_free(sema, M_SEM); + sys_free(semu, M_SEM); + for (int i = 0; i < seminfo.semmni; i++) + mtx_destroy(&sema_mtx[i]); + mtx_destroy(&sem_mtx); + return (0); +} + +#ifndef __CYGWIN__ +static int +sysvsem_modload(struct module *module, int cmd, void *arg) +{ + int error = 0; + + switch (cmd) { + case MOD_LOAD: + seminit(); + break; + case MOD_UNLOAD: + error = semunload(); + break; + case MOD_SHUTDOWN: + break; + default: + error = EINVAL; + break; + } + return (error); +} + +static moduledata_t sysvsem_mod = { + "sysvsem", + &sysvsem_modload, + NULL +}; + +SYSCALL_MODULE_HELPER(semsys); +SYSCALL_MODULE_HELPER(__semctl); +SYSCALL_MODULE_HELPER(semget); +SYSCALL_MODULE_HELPER(semop); + +DECLARE_MODULE(sysvsem, sysvsem_mod, + SI_SUB_SYSV_SEM, SI_ORDER_FIRST); +MODULE_VERSION(sysvsem, 1); + +/* + * Entry point for all SEM calls + * + * MPSAFE + */ +int +semsys(td, uap) + struct thread *td; + /* XXX actually varargs. */ + struct semsys_args /* { + int which; + int a2; + int a3; + int a4; + int a5; + } */ *uap; +{ + int error; + + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + if (uap->which < 0 || + uap->which >= sizeof(semcalls)/sizeof(semcalls[0])) + return (EINVAL); + error = (*semcalls[uap->which])(td, &uap->a2); + return (error); +} +#endif /* __CYGWIN__ */ + +/* + * Allocate a new sem_undo structure for a process + * (returns ptr to structure or NULL if no more room) + */ + +static struct sem_undo * +semu_alloc(struct thread *td) +{ + int i; + struct sem_undo *suptr; + struct sem_undo **supptr; + int attempt; + + SEMUNDO_LOCKASSERT(MA_OWNED); + /* + * Try twice to allocate something. + * (we'll purge an empty structure after the first pass so + * two passes are always enough) + */ + + for (attempt = 0; attempt < 2; attempt++) { + /* + * Look for a free structure. + * Fill it in and return it if we find one. + */ + + for (i = 0; i < seminfo.semmnu; i++) { + suptr = SEMU(i); + if (suptr->un_proc == NULL) { + SLIST_INSERT_HEAD(&semu_list, suptr, un_next); + suptr->un_cnt = 0; + suptr->un_proc = td->td_proc; + return(suptr); + } + } + + /* + * We didn't find a free one, if this is the first attempt + * then try to free a structure. + */ + + if (attempt == 0) { + /* All the structures are in use - try to free one */ + int did_something = 0; + + SLIST_FOREACH_PREVPTR(suptr, supptr, &semu_list, + un_next) { + if (suptr->un_cnt == 0) { + suptr->un_proc = NULL; + did_something = 1; + *supptr = SLIST_NEXT(suptr, un_next); + break; + } + } + + /* If we didn't free anything then just give-up */ + if (!did_something) + return(NULL); + } else { + /* + * The second pass failed even though we freed + * something after the first pass! + * This is IMPOSSIBLE! + */ + panic("semu_alloc - second attempt failed"); + } + } + return (NULL); +} + +/* + * Adjust a particular entry for a particular proc + */ + +static int +semundo_adjust(struct thread *td, struct sem_undo **supptr, int semid, + int semnum, int adjval) +{ + struct proc *p = td->td_proc; + struct sem_undo *suptr; + struct undo *sunptr; + int i; + + SEMUNDO_LOCKASSERT(MA_OWNED); + /* Look for and remember the sem_undo if the caller doesn't provide + it */ + + suptr = *supptr; + if (suptr == NULL) { + SLIST_FOREACH(suptr, &semu_list, un_next) { + if (suptr->un_proc == p) { + *supptr = suptr; + break; + } + } + if (suptr == NULL) { + if (adjval == 0) + return(0); + suptr = semu_alloc(td); + if (suptr == NULL) + return(ENOSPC); + *supptr = suptr; + } + } + + /* + * Look for the requested entry and adjust it (delete if adjval becomes + * 0). + */ + sunptr = &suptr->un_ent[0]; + for (i = 0; i < suptr->un_cnt; i++, sunptr++) { + if (sunptr->un_id != semid || sunptr->un_num != semnum) + continue; + if (adjval != 0) { + adjval += sunptr->un_adjval; + if (adjval > seminfo.semaem || adjval < -seminfo.semaem) + return (ERANGE); + } + sunptr->un_adjval = adjval; + if (sunptr->un_adjval == 0) { + suptr->un_cnt--; + if (i < suptr->un_cnt) + suptr->un_ent[i] = + suptr->un_ent[suptr->un_cnt]; + } + return(0); + } + + /* Didn't find the right entry - create it */ + if (adjval == 0) + return(0); + if (adjval > seminfo.semaem || adjval < -seminfo.semaem) + return (ERANGE); + if (suptr->un_cnt != seminfo.semume) { + sunptr = &suptr->un_ent[suptr->un_cnt]; + suptr->un_cnt++; + sunptr->un_adjval = adjval; + sunptr->un_id = semid; sunptr->un_num = semnum; + } else + return(EINVAL); + return(0); +} + +static void +semundo_clear(int semid, int semnum) +{ + struct sem_undo *suptr; + + SEMUNDO_LOCKASSERT(MA_OWNED); + SLIST_FOREACH(suptr, &semu_list, un_next) { + struct undo *sunptr = &suptr->un_ent[0]; + int i = 0; + + while (i < suptr->un_cnt) { + if (sunptr->un_id == semid) { + if (semnum == -1 || sunptr->un_num == semnum) { + suptr->un_cnt--; + if (i < suptr->un_cnt) { + suptr->un_ent[i] = + suptr->un_ent[suptr->un_cnt]; + continue; + } + } + if (semnum != -1) + break; + } + i++, sunptr++; + } + } +} + +static int +semvalid(int semid, struct semid_ds *semaptr) +{ + + return ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || + semaptr->sem_perm.seq != IPCID_TO_SEQ(semid) ? EINVAL : 0); +} + +/* + * Note that the user-mode half of this passes a union, not a pointer + */ +#ifndef _SYS_SYSPROTO_H_ +struct __semctl_args { + int semid; + int semnum; + int cmd; + union semun *arg; +}; +#endif + +/* + * MPSAFE + */ +int +__semctl(struct thread *td, struct __semctl_args *uap) +{ + int semid = uap->semid; + int semnum = uap->semnum; + int cmd = uap->cmd; + u_short *array; + union semun *arg = uap->arg; + union semun real_arg; +#ifndef __CYGWIN__ + struct ucred *cred = td->td_ucred; +#endif + int i, rval, error; + struct semid_ds sbuf; + struct semid_ds *semaptr; + struct mtx *sema_mtxp; + u_short usval, count; + + DPRINTF(("call to semctl(%d, %d, %d, 0x%x)\n", + semid, semnum, cmd, arg)); + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + + array = NULL; + + switch(cmd) { +#ifdef __CYGWIN__ + case IPC_INFO: + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + return (error); + if (!semid) { + error = copyout(&seminfo, real_arg.buf, + sizeof(struct seminfo)); + td->td_retval[0] = error ? -1 : 0; + return (error); + } + if (semid > seminfo.semmni) + semid = seminfo.semmni; + error = copyout(sema, real_arg.buf, + semid * sizeof(struct semid_ds)); + td->td_retval[0] = error ? -1 : 0; + return (error); + case SEM_INFO: + if (!(error = copyin(arg, &real_arg, sizeof(real_arg)))) { + struct sem_info sem_info; + sem_info.sem_ids = semtots; + sem_info.sem_num = semtot; + error = copyout(&sem_info, real_arg.buf, + sizeof(struct sem_info)); + } + td->td_retval[0] = error ? -1 : 0; + return (error); + +#endif /* __CYGWIN__ */ + case SEM_STAT: + if (semid < 0 || semid >= seminfo.semmni) + return (EINVAL); + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + return (error); + semaptr = &sema[semid]; + sema_mtxp = &sema_mtx[semid]; + mtx_lock(sema_mtxp); + if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) { + error = EINVAL; + goto done2; + } + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + mtx_unlock(sema_mtxp); + error = copyout(semaptr, real_arg.buf, sizeof(struct semid_ds)); + rval = IXSEQ_TO_IPCID(semid,semaptr->sem_perm); + if (error == 0) + td->td_retval[0] = rval; + return (error); + } + + semid = IPCID_TO_IX(semid); + if (semid < 0 || semid >= seminfo.semmni) + return (EINVAL); + + semaptr = &sema[semid]; + sema_mtxp = &sema_mtx[semid]; + + error = 0; + rval = 0; + + switch (cmd) { + case IPC_RMID: + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_M))) + goto done2; +#ifdef __CYGWIN__ + semaptr->sem_perm.cuid = td->ipcblk->uid; + semaptr->sem_perm.uid = td->ipcblk->uid; +#else + semaptr->sem_perm.cuid = cred->cr_uid; + semaptr->sem_perm.uid = cred->cr_uid; +#endif + semtot -= semaptr->sem_nsems; + semtots--; + for (i = semaptr->sem_base - sem; i < semtot; i++) + sem[i] = sem[i + semaptr->sem_nsems]; + for (i = 0; i < seminfo.semmni; i++) { + if ((sema[i].sem_perm.mode & SEM_ALLOC) && + sema[i].sem_base > semaptr->sem_base) + sema[i].sem_base -= semaptr->sem_nsems; + } + semaptr->sem_perm.mode = 0; + SEMUNDO_LOCK(); + semundo_clear(semid, -1); + SEMUNDO_UNLOCK(); + wakeup(semaptr); + break; + + case IPC_SET: + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + goto done2; + if ((error = copyin(real_arg.buf, &sbuf, sizeof(sbuf))) != 0) + goto done2; + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_M))) + goto done2; + semaptr->sem_perm.uid = sbuf.sem_perm.uid; + semaptr->sem_perm.gid = sbuf.sem_perm.gid; + semaptr->sem_perm.mode = (semaptr->sem_perm.mode & ~0777) | + (sbuf.sem_perm.mode & 0777); + semaptr->sem_ctime = time (NULL); + break; + + case IPC_STAT: + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + goto done2; + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + sbuf = *semaptr; + mtx_unlock(sema_mtxp); + error = copyout(semaptr, real_arg.buf, + sizeof(struct semid_ds)); + break; + + case GETNCNT: + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + if (semnum < 0 || semnum >= semaptr->sem_nsems) { + error = EINVAL; + goto done2; + } + rval = semaptr->sem_base[semnum].semncnt; + break; + + case GETPID: + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + if (semnum < 0 || semnum >= semaptr->sem_nsems) { + error = EINVAL; + goto done2; + } + rval = semaptr->sem_base[semnum].sempid; + break; + + case GETVAL: + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + if (semnum < 0 || semnum >= semaptr->sem_nsems) { + error = EINVAL; + goto done2; + } + rval = semaptr->sem_base[semnum].semval; + break; + + case GETALL: + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + goto done2; + array = (u_short *) sys_malloc(sizeof(*array) * semaptr->sem_nsems, M_TEMP, + M_WAITOK); + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + for (i = 0; i < semaptr->sem_nsems; i++) + array[i] = semaptr->sem_base[i].semval; + mtx_unlock(sema_mtxp); + error = copyout(array, real_arg.array, + i * sizeof(real_arg.array[0])); + break; + + case GETZCNT: + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_R))) + goto done2; + if (semnum < 0 || semnum >= semaptr->sem_nsems) { + error = EINVAL; + goto done2; + } + rval = semaptr->sem_base[semnum].semzcnt; + break; + + case SETVAL: + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + goto done2; + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_W))) + goto done2; + if (semnum < 0 || semnum >= semaptr->sem_nsems) { + error = EINVAL; + goto done2; + } + if (real_arg.val < 0 || real_arg.val > seminfo.semvmx) { + error = ERANGE; + goto done2; + } + semaptr->sem_base[semnum].semval = real_arg.val; + SEMUNDO_LOCK(); + semundo_clear(semid, semnum); + SEMUNDO_UNLOCK(); + wakeup(semaptr); + break; + + case SETALL: + mtx_lock(sema_mtxp); +raced: + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + count = semaptr->sem_nsems; + mtx_unlock(sema_mtxp); + if ((error = copyin(arg, &real_arg, sizeof(real_arg))) != 0) + goto done2; + array = (u_short *) sys_malloc(sizeof(*array) * count, M_TEMP, M_WAITOK); + copyin(real_arg.array, array, count * sizeof(*array)); + if (error) + break; + mtx_lock(sema_mtxp); + if ((error = semvalid(uap->semid, semaptr)) != 0) + goto done2; + /* we could have raced? */ + if (count != semaptr->sem_nsems) { + sys_free(array, M_TEMP); + array = NULL; + goto raced; + } + if ((error = ipcperm(td, &semaptr->sem_perm, IPC_W))) + goto done2; + for (i = 0; i < semaptr->sem_nsems; i++) { + usval = array[i]; + if (usval > seminfo.semvmx) { + error = ERANGE; + break; + } + semaptr->sem_base[i].semval = usval; + } + SEMUNDO_LOCK(); + semundo_clear(semid, -1); + SEMUNDO_UNLOCK(); + wakeup(semaptr); + break; + + default: + error = EINVAL; + break; + } + + if (error == 0) + td->td_retval[0] = rval; +done2: + if (mtx_owned(sema_mtxp)) + mtx_unlock(sema_mtxp); + if (array != NULL) + sys_free(array, M_TEMP); + return(error); +} + +#ifndef _SYS_SYSPROTO_H_ +struct semget_args { + key_t key; + int nsems; + int semflg; +}; +#endif + +/* + * MPSAFE + */ +int +semget(struct thread *td, struct semget_args *uap) +{ + int semid, error = 0; + key_t key = uap->key; + int nsems = uap->nsems; + int semflg = uap->semflg; +#ifndef __CYGWIN__ + struct ucred *cred = td->td_ucred; +#endif + + DPRINTF(("semget(0x%x, %d, 0%o)\n", key, nsems, semflg)); + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + + mtx_lock(&Giant); + if (key != IPC_PRIVATE) { + for (semid = 0; semid < seminfo.semmni; semid++) { + if ((sema[semid].sem_perm.mode & SEM_ALLOC) && + sema[semid].sem_perm.key == key) + break; + } + if (semid < seminfo.semmni) { + DPRINTF(("found public key\n")); + if ((error = ipcperm(td, &sema[semid].sem_perm, + semflg & 0700))) { + goto done2; + } + if (nsems > 0 && sema[semid].sem_nsems < nsems) { + DPRINTF(("too small\n")); + error = EINVAL; + goto done2; + } + if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) { + DPRINTF(("not exclusive\n")); + error = EEXIST; + goto done2; + } + goto found; + } + } + + DPRINTF(("need to allocate the semid_ds\n")); + if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) { + if (nsems <= 0 || nsems > seminfo.semmsl) { + DPRINTF(("nsems out of range (0<%d<=%d)\n", nsems, + seminfo.semmsl)); + error = EINVAL; + goto done2; + } + if (nsems > seminfo.semmns - semtot) { + DPRINTF(( + "not enough semaphores left (need %d, got %d)\n", + nsems, seminfo.semmns - semtot)); + error = ENOSPC; + goto done2; + } + for (semid = 0; semid < seminfo.semmni; semid++) { + if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0) + break; + } + if (semid == seminfo.semmni) { + DPRINTF(("no more semid_ds's available\n")); + error = ENOSPC; + goto done2; + } + DPRINTF(("semid %d is available\n", semid)); + sema[semid].sem_perm.key = key; +#ifdef __CYGWIN__ + sema[semid].sem_perm.cuid = td->ipcblk->uid; + sema[semid].sem_perm.uid = td->ipcblk->uid; + sema[semid].sem_perm.cgid = td->ipcblk->gid; + sema[semid].sem_perm.gid = td->ipcblk->gid; +#else + sema[semid].sem_perm.cuid = cred->cr_uid; + sema[semid].sem_perm.uid = cred->cr_uid; + sema[semid].sem_perm.cgid = cred->cr_gid; + sema[semid].sem_perm.gid = cred->cr_gid; +#endif + sema[semid].sem_perm.mode = (semflg & 0777) | SEM_ALLOC; + sema[semid].sem_perm.seq = + (sema[semid].sem_perm.seq + 1) & 0x7fff; + sema[semid].sem_nsems = nsems; + sema[semid].sem_otime = 0; + sema[semid].sem_ctime = time (NULL); + sema[semid].sem_base = &sem[semtot]; + semtot += nsems; + semtots++; + bzero(sema[semid].sem_base, + sizeof(sema[semid].sem_base[0])*nsems); + DPRINTF(("sembase = 0x%x, next = 0x%x\n", sema[semid].sem_base, + &sem[semtot])); + } else { + DPRINTF(("didn't find it and wasn't asked to create it\n")); + error = ENOENT; + goto done2; + } + +found: + td->td_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].sem_perm); +done2: +#ifdef __CYGWIN__ + if (!error) + ipcexit_creat_hookthread (td); +#endif + mtx_unlock(&Giant); + return (error); +} + +#ifndef _SYS_SYSPROTO_H_ +struct semop_args { + int semid; + struct sembuf *sops; + size_t nsops; +}; +#endif + +/* + * MPSAFE + */ +int +semop(struct thread *td, struct semop_args *uap) +{ + int semid = uap->semid; + size_t nsops = uap->nsops; + struct sembuf *sops; + struct semid_ds *semaptr; + struct sembuf *sopptr = 0; + struct sem *semptr = 0; + struct sem_undo *suptr; + struct mtx *sema_mtxp; + size_t i, j, k; + int error; + int do_wakeup, do_undos; + + DPRINTF(("call to semop(%d, 0x%x, %u)\n", semid, uap->sops, nsops)); + + if (!jail_sysvipc_allowed && jailed(td->td_ucred)) + return (ENOSYS); + + semid = IPCID_TO_IX(semid); /* Convert back to zero origin */ + + if (semid < 0 || semid >= seminfo.semmni) + return (EINVAL); + + /* Allocate memory for sem_ops */ + if (nsops > (unsigned long) seminfo.semopm) { + DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm, + nsops)); + return (E2BIG); + } + sops = (struct sembuf *) sys_malloc(nsops * sizeof(sops[0]), M_SEM, M_WAITOK); + if ((error = copyin(uap->sops, sops, nsops * sizeof(sops[0]))) != 0) { + DPRINTF(("error = %d from copyin(%08x, %08x, %d)\n", error, + uap->sops, sops, nsops * sizeof(sops[0]))); + sys_free(sops, M_SEM); + return (error); + } + + semaptr = &sema[semid]; + sema_mtxp = &sema_mtx[semid]; + mtx_lock(sema_mtxp); + if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) { + error = EINVAL; + goto done2; + } + if (semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { + error = EINVAL; + goto done2; + } + /* + * Initial pass thru sops to see what permissions are needed. + * Also perform any checks that don't need repeating on each + * attempt to satisfy the request vector. + */ + j = 0; /* permission needed */ + do_undos = 0; + for (i = 0; i < nsops; i++) { + sopptr = &sops[i]; + if (sopptr->sem_num >= semaptr->sem_nsems) { + error = EFBIG; + goto done2; + } + if (sopptr->sem_flg & SEM_UNDO && sopptr->sem_op != 0) + do_undos = 1; + j |= (sopptr->sem_op == 0) ? SEM_R : SEM_A; + } + + if ((error = ipcperm(td, &semaptr->sem_perm, j))) { + DPRINTF(("error = %d from ipaccess\n", error)); + goto done2; + } + + /* + * Loop trying to satisfy the vector of requests. + * If we reach a point where we must wait, any requests already + * performed are rolled back and we go to sleep until some other + * process wakes us up. At this point, we start all over again. + * + * This ensures that from the perspective of other tasks, a set + * of requests is atomic (never partially satisfied). + */ + for (;;) { + do_wakeup = 0; + error = 0; /* error return if necessary */ + + for (i = 0; i < nsops; i++) { + sopptr = &sops[i]; + semptr = &semaptr->sem_base[sopptr->sem_num]; + + DPRINTF(( + "semop: semaptr=%x, sem_base=%x, " + "semptr=%x, sem[%d]=%d : op=%d, flag=%s\n", + semaptr, semaptr->sem_base, semptr, + sopptr->sem_num, semptr->semval, sopptr->sem_op, + (sopptr->sem_flg & IPC_NOWAIT) ? + "nowait" : "wait")); + + if (sopptr->sem_op < 0) { + if (semptr->semval + sopptr->sem_op < 0) { + DPRINTF(("semop: can't do it now\n")); + break; + } else { + semptr->semval += sopptr->sem_op; + if (semptr->semval == 0 && + semptr->semzcnt > 0) + do_wakeup = 1; + } + } else if (sopptr->sem_op == 0) { + if (semptr->semval != 0) { + DPRINTF(("semop: not zero now\n")); + break; + } + } else if (semptr->semval + sopptr->sem_op > + seminfo.semvmx) { + error = ERANGE; + break; + } else { + if (semptr->semncnt > 0) + do_wakeup = 1; + semptr->semval += sopptr->sem_op; + } + } + + /* + * Did we get through the entire vector? + */ + if (i >= nsops) + goto done; + + /* + * No ... rollback anything that we've already done + */ + DPRINTF(("semop: rollback 0 through %d\n", i-1)); + for (j = 0; j < i; j++) + semaptr->sem_base[sops[j].sem_num].semval -= + sops[j].sem_op; + + /* If we detected an error, return it */ + if (error != 0) + goto done2; + + /* + * If the request that we couldn't satisfy has the + * NOWAIT flag set then return with EAGAIN. + */ + if (sopptr->sem_flg & IPC_NOWAIT) { + error = EAGAIN; + goto done2; + } + + if (sopptr->sem_op == 0) + semptr->semzcnt++; + else + semptr->semncnt++; + + DPRINTF(("semop: good night!\n")); + error = msleep(semaptr, sema_mtxp, (PZERO - 4) | PCATCH, + "semwait", 0); + DPRINTF(("semop: good morning (error=%d)!\n", error)); + + if (error != 0) { +#ifdef __CYGWIN__ + if (error != EIDRM) +#endif /* __CYGWIN__ */ + error = EINTR; + goto done2; + } + DPRINTF(("semop: good morning!\n")); + + /* + * Make sure that the semaphore still exists + */ + if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 || + semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid)) { + error = EIDRM; + goto done2; + } + + /* + * The semaphore is still alive. Readjust the count of + * waiting processes. + */ + if (sopptr->sem_op == 0) + semptr->semzcnt--; + else + semptr->semncnt--; + } + +done: + /* + * Process any SEM_UNDO requests. + */ + if (do_undos) { + SEMUNDO_LOCK(); + suptr = NULL; + for (i = 0; i < nsops; i++) { + /* + * We only need to deal with SEM_UNDO's for non-zero + * op's. + */ + int adjval; + + if ((sops[i].sem_flg & SEM_UNDO) == 0) + continue; + adjval = sops[i].sem_op; + if (adjval == 0) + continue; + error = semundo_adjust(td, &suptr, semid, + sops[i].sem_num, -adjval); + if (error == 0) + continue; + + /* + * Oh-Oh! We ran out of either sem_undo's or undo's. + * Rollback the adjustments to this point and then + * rollback the semaphore ups and down so we can return + * with an error with all structures restored. We + * rollback the undo's in the exact reverse order that + * we applied them. This guarantees that we won't run + * out of space as we roll things back out. + */ + for (j = 0; j < i; j++) { + k = i - j - 1; + if ((sops[k].sem_flg & SEM_UNDO) == 0) + continue; + adjval = sops[k].sem_op; + if (adjval == 0) + continue; + if (semundo_adjust(td, &suptr, semid, + sops[k].sem_num, adjval) != 0) + panic("semop - can't undo undos"); + } + + for (j = 0; j < nsops; j++) + semaptr->sem_base[sops[j].sem_num].semval -= + sops[j].sem_op; + + DPRINTF(("error = %d from semundo_adjust\n", error)); + SEMUNDO_UNLOCK(); + goto done2; + } /* loop through the sops */ + SEMUNDO_UNLOCK(); + } /* if (do_undos) */ + + /* We're definitely done - set the sempid's and time */ + for (i = 0; i < nsops; i++) { + sopptr = &sops[i]; + semptr = &semaptr->sem_base[sopptr->sem_num]; + semptr->sempid = td->td_proc->p_pid; + } + semaptr->sem_otime = time (NULL); + + /* + * Do a wakeup if any semaphore was up'd whilst something was + * sleeping on it. + */ + if (do_wakeup) { + DPRINTF(("semop: doing wakeup\n")); + wakeup(semaptr); + DPRINTF(("semop: back from wakeup\n")); + } + DPRINTF(("semop: done\n")); + td->td_retval[0] = 0; +done2: + mtx_unlock(sema_mtxp); + sys_free(sops, M_SEM); + return (error); +} + +/* + * Go through the undo structures for this process and apply the adjustments to + * semaphores. + */ +void +semexit_myhook(void *arg, struct proc *p) +{ + struct sem_undo *suptr; + struct sem_undo **supptr; + +#ifdef __CYGWIN__ + /* + * Search all mutexes, if some of them are still owned by the + * leaving process. If so, unlock them. + */ + if (sem_mtx.owner == p->winpid) + mtx_unlock(&sem_mtx); + for (int i = 0; i < seminfo.semmni; i++) + if (sema_mtx[i].owner == p->winpid) + mtx_unlock(&sema_mtx[i]); +#endif /* __CYGWIN__ */ + + /* + * Go through the chain of undo vectors looking for one + * associated with this process. + */ + SEMUNDO_HOOKLOCK(); + SLIST_FOREACH_PREVPTR(suptr, supptr, &semu_list, un_next) { + if (suptr->un_proc == p) + break; + } + SEMUNDO_UNLOCK(); + + if (suptr == NULL) + return; + + DPRINTF(("proc @%08x has undo structure with %d entries\n", p, + suptr->un_cnt)); + + /* + * If there are any active undo elements then process them. + */ + if (suptr->un_cnt > 0) { + int ix; + + for (ix = 0; ix < suptr->un_cnt; ix++) { + int semid = suptr->un_ent[ix].un_id; + int semnum = suptr->un_ent[ix].un_num; + int adjval = suptr->un_ent[ix].un_adjval; + struct semid_ds *semaptr; + struct mtx *sema_mtxp; + + semaptr = &sema[semid]; + sema_mtxp = &sema_mtx[semid]; +#ifdef __CYGWIN__ + _mtx_lock(sema_mtxp, p->winpid, __FILE__, __LINE__); +#else + mtx_lock(sema_mtxp); +#endif + SEMUNDO_HOOKLOCK(); + if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0) + panic("semexit - semid not allocated"); + if (semnum >= semaptr->sem_nsems) + panic("semexit - semnum out of range"); + + DPRINTF(( + "semexit: %08x id=%d num=%d(adj=%d) ; sem=%d\n", + suptr->un_proc, suptr->un_ent[ix].un_id, + suptr->un_ent[ix].un_num, + suptr->un_ent[ix].un_adjval, + semaptr->sem_base[semnum].semval)); + + if (adjval < 0) { + if (semaptr->sem_base[semnum].semval < -adjval) + semaptr->sem_base[semnum].semval = 0; + else + semaptr->sem_base[semnum].semval += + adjval; + } else + semaptr->sem_base[semnum].semval += adjval; + + wakeup(semaptr); + DPRINTF(("semexit: back from wakeup\n")); + mtx_unlock(sema_mtxp); + SEMUNDO_UNLOCK(); + } + } + + /* + * Deallocate the undo vector. + */ + DPRINTF(("removing vector\n")); + suptr->un_proc = NULL; + *supptr = SLIST_NEXT(suptr, un_next); +} + +#ifndef __CYGWIN__ +static int +sysctl_sema(SYSCTL_HANDLER_ARGS) +{ + + return (SYSCTL_OUT(req, sema, + sizeof(struct semid_ds) * seminfo.semmni)); +} +#endif /* __CYGWIN__ */ +#endif /* __OUTSIDE_CYGWIN__ */ |