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-rw-r--r--sys/kern/sysv_sem.c1229
1 files changed, 1229 insertions, 0 deletions
diff --git a/sys/kern/sysv_sem.c b/sys/kern/sysv_sem.c
new file mode 100644
index 0000000..58e502d
--- /dev/null
+++ b/sys/kern/sysv_sem.c
@@ -0,0 +1,1229 @@
+/*
+ * Implementation of SVID semaphores
+ *
+ * Author: Daniel Boulet
+ *
+ * This software is provided ``AS IS'' without any warranties of any kind.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_sysvipc.h"
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/sysproto.h>
+#include <sys/eventhandler.h>
+#include <sys/kernel.h>
+#include <sys/proc.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/sem.h>
+#include <sys/syscall.h>
+#include <sys/sysent.h>
+#include <sys/sysctl.h>
+#include <sys/malloc.h>
+#include <sys/jail.h>
+
+static MALLOC_DEFINE(M_SEM, "sem", "SVID compatible semaphores");
+
+#ifdef SEM_DEBUG
+#define DPRINTF(a) printf a
+#else
+#define DPRINTF(a)
+#endif
+
+static void seminit(void);
+static int sysvsem_modload(struct module *, int, void *);
+static int semunload(void);
+static void semexit_myhook(void *arg, struct proc *p);
+static int sysctl_sema(SYSCTL_HANDLER_ARGS);
+static int semvalid(int semid, struct semid_ds *semaptr);
+
+#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
+
+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);
+
+/* 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
+};
+
+static struct mtx sem_mtx; /* semaphore global lock */
+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 */
+static eventhandler_tag semexit_tag;
+
+#define SEMUNDO_MTX sem_mtx
+#define SEMUNDO_LOCK() mtx_lock(&SEMUNDO_MTX);
+#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 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 {
+ short un_adjval; /* adjust on exit values */
+ short un_num; /* semaphore # */
+ int un_id; /* semid */
+ } 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
+
+#define SEMVMX 32767 /* semaphore maximum value */
+#define SEMAEM 16384 /* adjust on exit max value */
+
+/*
+ * 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 = {
+ SEMMAP, /* # of entries in semaphore map */
+ SEMMNI, /* # of semaphore identifiers */
+ SEMMNS, /* # of semaphores in system */
+ SEMMNU, /* # of undo structures in system */
+ SEMMSL, /* max # of semaphores per id */
+ SEMOPM, /* max # of operations per semop call */
+ SEMUME, /* max # of undo entries per process */
+ SEMUSZ, /* size in bytes of undo structure */
+ SEMVMX, /* semaphore maximum value */
+ SEMAEM /* adjust on exit max value */
+};
+
+SYSCTL_DECL(_kern_ipc);
+SYSCTL_INT(_kern_ipc, OID_AUTO, semmap, CTLFLAG_RW, &seminfo.semmap, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semmni, CTLFLAG_RD, &seminfo.semmni, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semmns, CTLFLAG_RD, &seminfo.semmns, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semmnu, CTLFLAG_RD, &seminfo.semmnu, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semmsl, CTLFLAG_RW, &seminfo.semmsl, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semopm, CTLFLAG_RD, &seminfo.semopm, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semume, CTLFLAG_RD, &seminfo.semume, 0, "");
+SYSCTL_INT(_kern_ipc, OID_AUTO, semusz, CTLFLAG_RD, &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, "", "");
+
+static 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);
+
+ sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
+ sema = malloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM,
+ M_WAITOK);
+ sema_mtx = malloc(sizeof(struct mtx) * seminfo.semmni, M_SEM,
+ M_WAITOK | M_ZERO);
+ semu = 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);
+ semexit_tag = EVENTHANDLER_REGISTER(process_exit, semexit_myhook, NULL,
+ EVENTHANDLER_PRI_ANY);
+}
+
+static int
+semunload(void)
+{
+ int i;
+
+ if (semtot != 0)
+ return (EBUSY);
+
+ EVENTHANDLER_DEREGISTER(process_exit, semexit_tag);
+ free(sem, M_SEM);
+ free(sema, M_SEM);
+ free(semu, M_SEM);
+ for (i = 0; i < seminfo.semmni; i++)
+ mtx_destroy(&sema_mtx[i]);
+ mtx_destroy(&sem_mtx);
+ return (0);
+}
+
+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 /* {
+ u_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 >= sizeof(semcalls)/sizeof(semcalls[0]))
+ return (EINVAL);
+ error = (*semcalls[uap->which])(td, &uap->a2);
+ return (error);
+}
+
+/*
+ * 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(td)
+ 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 any empty structures 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 some structures.
+ */
+
+ if (attempt == 0) {
+ /* All the structures are in use - try to free some */
+ 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);
+ }
+ }
+
+ /* 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(td, supptr, semid, semnum, adjval)
+ struct thread *td;
+ struct sem_undo **supptr;
+ int semid, 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(semid, semnum)
+ int semid, 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(semid, semaptr)
+ 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(td, uap)
+ 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;
+ struct ucred *cred = td->td_ucred;
+ 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) {
+ 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;
+ semaptr->sem_perm.cuid = cred->cr_uid;
+ semaptr->sem_perm.uid = cred->cr_uid;
+ semtot -= semaptr->sem_nsems;
+ 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_second;
+ 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 = 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 = 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) {
+ 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)
+ free(array, M_TEMP);
+ return(error);
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct semget_args {
+ key_t key;
+ int nsems;
+ int semflg;
+};
+#endif
+
+/*
+ * MPSAFE
+ */
+int
+semget(td, uap)
+ struct thread *td;
+ struct semget_args *uap;
+{
+ int semid, error = 0;
+ int key = uap->key;
+ int nsems = uap->nsems;
+ int semflg = uap->semflg;
+ struct ucred *cred = td->td_ucred;
+
+ 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;
+ 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;
+ 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_second;
+ sema[semid].sem_base = &sem[semtot];
+ semtot += nsems;
+ 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:
+ mtx_unlock(&Giant);
+ return (error);
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct semop_args {
+ int semid;
+ struct sembuf *sops;
+ size_t nsops;
+};
+#endif
+
+/*
+ * MPSAFE
+ */
+int
+semop(td, uap)
+ 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, 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 > seminfo.semopm) {
+ DPRINTF(("too many sops (max=%d, nsops=%d)\n", seminfo.semopm,
+ nsops));
+ return (E2BIG);
+ }
+ sops = 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])));
+ 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) {
+ 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_second;
+
+ /*
+ * 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);
+ free(sops, M_SEM);
+ return (error);
+}
+
+/*
+ * Go through the undo structures for this process and apply the adjustments to
+ * semaphores.
+ */
+static void
+semexit_myhook(arg, p)
+ void *arg;
+ struct proc *p;
+{
+ struct sem_undo *suptr;
+ struct sem_undo **supptr;
+
+ /*
+ * Go through the chain of undo vectors looking for one
+ * associated with this process.
+ */
+ SEMUNDO_LOCK();
+ 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];
+ mtx_lock(sema_mtxp);
+ SEMUNDO_LOCK();
+ 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);
+}
+
+static int
+sysctl_sema(SYSCTL_HANDLER_ARGS)
+{
+
+ return (SYSCTL_OUT(req, sema,
+ sizeof(struct semid_ds) * seminfo.semmni));
+}
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