freebsd-dev/sys/kern/sysv_sem.c

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1999-08-28 01:08:13 +00:00
/* $FreeBSD$ */
/*
* Implementation of SVID semaphores
*
* Author: Daniel Boulet
*
* This software is provided ``AS IS'' without any warranties of any kind.
*/
#include "opt_sysvipc.h"
#include <sys/param.h>
#include <sys/systm.h>
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/sem.h>
#include <sys/syscall.h>
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
#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");
static void seminit __P((void));
static int sysvsem_modload __P((struct module *, int, void *));
static int semunload __P((void));
static void semexit_myhook __P((struct proc *p));
#ifndef _SYS_SYSPROTO_H_
struct __semctl_args;
int __semctl __P((struct proc *p, struct __semctl_args *uap));
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
struct semget_args;
int semget __P((struct proc *p, struct semget_args *uap));
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
struct semop_args;
int semop __P((struct proc *p, struct semop_args *uap));
#endif
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
static struct sem_undo *semu_alloc __P((struct proc *p));
static int semundo_adjust __P((struct proc *p, struct sem_undo **supptr,
int semid, int semnum, int adjval));
static void semundo_clear __P((int semid, int semnum));
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
/* 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
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
};
static int semtot = 0;
static struct semid_ds *sema; /* semaphore id pool */
static struct sem *sem; /* semaphore pool */
static struct sem_undo *semu_list; /* list of active undo structures */
static int *semu; /* undo structure pool */
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 {
struct 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, "");
#if 0
RO seminfo.semmap /* SEMMAP unused */
RO seminfo.semmni
RO seminfo.semmns
RO seminfo.semmnu /* undo entries per system */
RW seminfo.semmsl
RO seminfo.semopm /* SEMOPM unused */
RO seminfo.semume
RO seminfo.semusz /* param - derived from SEMUME for per-proc sizeof */
RO seminfo.semvmx /* SEMVMX unused - user param */
RO seminfo.semaem /* SEMAEM unused - user param */
#endif
static void
seminit(void)
{
register int i;
sem = malloc(sizeof(struct sem) * seminfo.semmns, M_SEM, M_WAITOK);
if (sem == NULL)
panic("sem is NULL");
sema = malloc(sizeof(struct semid_ds) * seminfo.semmni, M_SEM, M_WAITOK);
if (sema == NULL)
panic("sema is NULL");
semu = malloc(seminfo.semmnu * seminfo.semusz, M_SEM, M_WAITOK);
if (semu == NULL)
panic("semu is NULL");
for (i = 0; i < seminfo.semmni; i++) {
sema[i].sem_base = 0;
sema[i].sem_perm.mode = 0;
}
for (i = 0; i < seminfo.semmnu; i++) {
register struct sem_undo *suptr = SEMU(i);
suptr->un_proc = NULL;
}
semu_list = NULL;
semexit_hook = &semexit_myhook;
}
static int
semunload(void)
{
if (semtot != 0)
return (EBUSY);
free(sem, M_SEM);
free(sema, M_SEM);
free(semu, M_SEM);
semexit_hook = NULL;
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, 5);
SYSCALL_MODULE_HELPER(__semctl, 4);
SYSCALL_MODULE_HELPER(semget, 3);
SYSCALL_MODULE_HELPER(semop, 3);
DECLARE_MODULE(sysvsem, sysvsem_mod,
SI_SUB_SYSV_SEM, SI_ORDER_FIRST);
MODULE_VERSION(sysvsem, 1);
/*
* Entry point for all SEM calls
*/
int
semsys(p, uap)
struct proc *p;
Start including <sys/sysproto.h> to get the correct args structs and prototypes for all syscalls. The args structs are still declared in comments as in VOP implementation functions. I don't like the duplication for this, but several more layers of changes are required to get it right. First we need to catch up with 4.4lite2, which uses macros to handle struct padding. Then we need to catch up with NetBSD, which passes the args correctly (as void *). Then we need to handle varargs functions and struct padding better. I think all the details can be hidden in machine-generated functions so that the args structs and verbose macros to reference them don't have to appear in the core sources. Add prototypes. Add bogus casts to hide the evil type puns exposed by the previous steps. &uap[1] was used to get at the args after the first. This worked because only the first arg in *uap was declared. This broke when the machine- genenerated args struct declared all the args (actually it declares extra args in some cases and depends on the user stack having some accessible junk after the last arg, not to mention the user args being on the stack. It isn't possible to declare a correct args struct for a varargs syscall). The msgsys(), semsys() and shmsys() syscall interfaces are BAD because they multiplex several syscalls that have different types of args. There was no reason to duplicate this sysv braindamage but now we're stuck with it. NetBSD has reimplemented the syscalls properly as separate syscalls #220-231. Declare static functions as static in both their prototype and their implementation (the latter is optional, and this misfeature was used). Remove gratuitous #includes. Continue cleaning up new init stuff.
1995-10-21 19:50:00 +00:00
/* XXX actually varargs. */
struct semsys_args /* {
u_int which;
int a2;
int a3;
int a4;
int a5;
} */ *uap;
{
if (!jail_sysvipc_allowed && jailed(p->p_ucred))
return (ENOSYS);
if (uap->which >= sizeof(semcalls)/sizeof(semcalls[0]))
return (EINVAL);
return ((*semcalls[uap->which])(p, &uap->a2));
}
/*
* 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(p)
struct proc *p;
{
register int i;
register struct sem_undo *suptr;
register struct sem_undo **supptr;
int attempt;
/*
* 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) {
suptr->un_next = semu_list;
semu_list = suptr;
suptr->un_cnt = 0;
suptr->un_proc = p;
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;
supptr = &semu_list;
while ((suptr = *supptr) != NULL) {
if (suptr->un_cnt == 0) {
suptr->un_proc = NULL;
*supptr = suptr->un_next;
did_something = 1;
} else
supptr = &(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");
}
}
1994-09-17 13:24:29 +00:00
return (NULL);
}
/*
* Adjust a particular entry for a particular proc
*/
static int
semundo_adjust(p, supptr, semid, semnum, adjval)
register struct proc *p;
struct sem_undo **supptr;
int semid, semnum;
int adjval;
{
register struct sem_undo *suptr;
register struct undo *sunptr;
int i;
/* Look for and remember the sem_undo if the caller doesn't provide
it */
suptr = *supptr;
if (suptr == NULL) {
for (suptr = semu_list; suptr != NULL;
suptr = suptr->un_next) {
if (suptr->un_proc == p) {
*supptr = suptr;
break;
}
}
if (suptr == NULL) {
if (adjval == 0)
return(0);
suptr = semu_alloc(p);
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)
sunptr->un_adjval = 0;
else
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 (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;
{
register struct sem_undo *suptr;
for (suptr = semu_list; suptr != NULL; suptr = suptr->un_next) {
register struct undo *sunptr = &suptr->un_ent[0];
register 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++;
}
}
}
/*
* 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
int
__semctl(p, uap)
struct proc *p;
register struct __semctl_args *uap;
{
int semid = uap->semid;
int semnum = uap->semnum;
int cmd = uap->cmd;
union semun *arg = uap->arg;
union semun real_arg;
struct ucred *cred = p->p_ucred;
int i, rval, eval;
struct semid_ds sbuf;
register struct semid_ds *semaptr;
#ifdef SEM_DEBUG
printf("call to semctl(%d, %d, %d, 0x%x)\n", semid, semnum, cmd, arg);
#endif
if (!jail_sysvipc_allowed && jailed(p->p_ucred))
return (ENOSYS);
semid = IPCID_TO_IX(semid);
if (semid < 0 || semid >= seminfo.semmsl)
return(EINVAL);
semaptr = &sema[semid];
if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid))
return(EINVAL);
eval = 0;
rval = 0;
switch (cmd) {
case IPC_RMID:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_M)))
return(eval);
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_clear(semid, -1);
wakeup((caddr_t)semaptr);
break;
case IPC_SET:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_M)))
return(eval);
if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
return(eval);
if ((eval = copyin(real_arg.buf, (caddr_t)&sbuf,
sizeof(sbuf))) != 0)
return(eval);
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 ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
return(eval);
if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
return(eval);
eval = copyout((caddr_t)semaptr, real_arg.buf,
sizeof(struct semid_ds));
break;
case GETNCNT:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
return(eval);
if (semnum < 0 || semnum >= semaptr->sem_nsems)
return(EINVAL);
rval = semaptr->sem_base[semnum].semncnt;
break;
case GETPID:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
return(eval);
if (semnum < 0 || semnum >= semaptr->sem_nsems)
return(EINVAL);
rval = semaptr->sem_base[semnum].sempid;
break;
case GETVAL:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
return(eval);
if (semnum < 0 || semnum >= semaptr->sem_nsems)
return(EINVAL);
rval = semaptr->sem_base[semnum].semval;
break;
case GETALL:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
return(eval);
if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
return(eval);
for (i = 0; i < semaptr->sem_nsems; i++) {
eval = copyout((caddr_t)&semaptr->sem_base[i].semval,
&real_arg.array[i], sizeof(real_arg.array[0]));
if (eval != 0)
break;
}
break;
case GETZCNT:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_R)))
return(eval);
if (semnum < 0 || semnum >= semaptr->sem_nsems)
return(EINVAL);
rval = semaptr->sem_base[semnum].semzcnt;
break;
case SETVAL:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_W)))
return(eval);
if (semnum < 0 || semnum >= semaptr->sem_nsems)
return(EINVAL);
if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
return(eval);
semaptr->sem_base[semnum].semval = real_arg.val;
semundo_clear(semid, semnum);
wakeup((caddr_t)semaptr);
break;
case SETALL:
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_W)))
return(eval);
if ((eval = copyin(arg, &real_arg, sizeof(real_arg))) != 0)
return(eval);
for (i = 0; i < semaptr->sem_nsems; i++) {
eval = copyin(&real_arg.array[i],
(caddr_t)&semaptr->sem_base[i].semval,
sizeof(real_arg.array[0]));
if (eval != 0)
break;
}
semundo_clear(semid, -1);
wakeup((caddr_t)semaptr);
break;
default:
return(EINVAL);
}
if (eval == 0)
p->p_retval[0] = rval;
return(eval);
}
#ifndef _SYS_SYSPROTO_H_
struct semget_args {
key_t key;
int nsems;
int semflg;
};
#endif
int
semget(p, uap)
struct proc *p;
register struct semget_args *uap;
{
int semid, eval;
int key = uap->key;
int nsems = uap->nsems;
int semflg = uap->semflg;
struct ucred *cred = p->p_ucred;
#ifdef SEM_DEBUG
printf("semget(0x%x, %d, 0%o)\n", key, nsems, semflg);
#endif
if (!jail_sysvipc_allowed && jailed(p->p_ucred))
return (ENOSYS);
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) {
#ifdef SEM_DEBUG
printf("found public key\n");
#endif
if ((eval = ipcperm(p, &sema[semid].sem_perm,
semflg & 0700)))
return(eval);
if (nsems > 0 && sema[semid].sem_nsems < nsems) {
#ifdef SEM_DEBUG
printf("too small\n");
#endif
return(EINVAL);
}
if ((semflg & IPC_CREAT) && (semflg & IPC_EXCL)) {
#ifdef SEM_DEBUG
printf("not exclusive\n");
#endif
return(EEXIST);
}
goto found;
}
}
#ifdef SEM_DEBUG
printf("need to allocate the semid_ds\n");
#endif
if (key == IPC_PRIVATE || (semflg & IPC_CREAT)) {
if (nsems <= 0 || nsems > seminfo.semmsl) {
#ifdef SEM_DEBUG
printf("nsems out of range (0<%d<=%d)\n", nsems,
seminfo.semmsl);
#endif
return(EINVAL);
}
if (nsems > seminfo.semmns - semtot) {
#ifdef SEM_DEBUG
printf("not enough semaphores left (need %d, got %d)\n",
nsems, seminfo.semmns - semtot);
#endif
return(ENOSPC);
}
for (semid = 0; semid < seminfo.semmni; semid++) {
if ((sema[semid].sem_perm.mode & SEM_ALLOC) == 0)
break;
}
if (semid == seminfo.semmni) {
#ifdef SEM_DEBUG
printf("no more semid_ds's available\n");
#endif
return(ENOSPC);
}
#ifdef SEM_DEBUG
printf("semid %d is available\n", semid);
#endif
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);
#ifdef SEM_DEBUG
printf("sembase = 0x%x, next = 0x%x\n", sema[semid].sem_base,
&sem[semtot]);
#endif
} else {
#ifdef SEM_DEBUG
printf("didn't find it and wasn't asked to create it\n");
#endif
return(ENOENT);
}
found:
p->p_retval[0] = IXSEQ_TO_IPCID(semid, sema[semid].sem_perm);
return(0);
}
#ifndef _SYS_SYSPROTO_H_
struct semop_args {
int semid;
struct sembuf *sops;
int nsops;
};
#endif
int
semop(p, uap)
struct proc *p;
register struct semop_args *uap;
{
int semid = uap->semid;
int nsops = uap->nsops;
struct sembuf sops[MAX_SOPS];
register struct semid_ds *semaptr;
register struct sembuf *sopptr;
register struct sem *semptr;
struct sem_undo *suptr = NULL;
int i, j, eval;
int do_wakeup, do_undos;
#ifdef SEM_DEBUG
printf("call to semop(%d, 0x%x, %d)\n", semid, sops, nsops);
#endif
if (!jail_sysvipc_allowed && jailed(p->p_ucred))
return (ENOSYS);
semid = IPCID_TO_IX(semid); /* Convert back to zero origin */
if (semid < 0 || semid >= seminfo.semmsl)
return(EINVAL);
semaptr = &sema[semid];
if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0)
return(EINVAL);
if (semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid))
return(EINVAL);
if ((eval = ipcperm(p, &semaptr->sem_perm, IPC_W))) {
#ifdef SEM_DEBUG
printf("eval = %d from ipaccess\n", eval);
#endif
return(eval);
}
if (nsops > MAX_SOPS) {
#ifdef SEM_DEBUG
printf("too many sops (max=%d, nsops=%d)\n", MAX_SOPS, nsops);
#endif
return(E2BIG);
}
if ((eval = copyin(uap->sops, &sops, nsops * sizeof(sops[0]))) != 0) {
#ifdef SEM_DEBUG
printf("eval = %d from copyin(%08x, %08x, %d)\n", eval,
uap->sops, &sops, nsops * sizeof(sops[0]));
#endif
return(eval);
}
1995-05-30 08:16:23 +00:00
/*
* 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).
*/
do_undos = 0;
for (;;) {
do_wakeup = 0;
for (i = 0; i < nsops; i++) {
sopptr = &sops[i];
if (sopptr->sem_num >= semaptr->sem_nsems)
return(EFBIG);
semptr = &semaptr->sem_base[sopptr->sem_num];
#ifdef SEM_DEBUG
printf("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");
#endif
if (sopptr->sem_op < 0) {
if (semptr->semval + sopptr->sem_op < 0) {
#ifdef SEM_DEBUG
printf("semop: can't do it now\n");
#endif
break;
} else {
semptr->semval += sopptr->sem_op;
if (semptr->semval == 0 &&
semptr->semzcnt > 0)
do_wakeup = 1;
}
if (sopptr->sem_flg & SEM_UNDO)
do_undos = 1;
} else if (sopptr->sem_op == 0) {
if (semptr->semval > 0) {
#ifdef SEM_DEBUG
printf("semop: not zero now\n");
#endif
break;
}
} else {
if (semptr->semncnt > 0)
do_wakeup = 1;
semptr->semval += sopptr->sem_op;
if (sopptr->sem_flg & SEM_UNDO)
do_undos = 1;
}
}
/*
* Did we get through the entire vector?
*/
if (i >= nsops)
goto done;
/*
* No ... rollback anything that we've already done
*/
#ifdef SEM_DEBUG
printf("semop: rollback 0 through %d\n", i-1);
#endif
for (j = 0; j < i; j++)
semaptr->sem_base[sops[j].sem_num].semval -=
sops[j].sem_op;
/*
* If the request that we couldn't satisfy has the
* NOWAIT flag set then return with EAGAIN.
*/
if (sopptr->sem_flg & IPC_NOWAIT)
return(EAGAIN);
if (sopptr->sem_op == 0)
semptr->semzcnt++;
else
semptr->semncnt++;
#ifdef SEM_DEBUG
printf("semop: good night!\n");
#endif
eval = tsleep((caddr_t)semaptr, (PZERO - 4) | PCATCH,
"semwait", 0);
#ifdef SEM_DEBUG
printf("semop: good morning (eval=%d)!\n", eval);
#endif
suptr = NULL; /* sem_undo may have been reallocated */
if (eval != 0)
return(EINTR);
#ifdef SEM_DEBUG
printf("semop: good morning!\n");
#endif
/*
* Make sure that the semaphore still exists
*/
if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0 ||
semaptr->sem_perm.seq != IPCID_TO_SEQ(uap->semid))
return(EIDRM);
/*
* 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) {
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;
eval = semundo_adjust(p, &suptr, semid,
sops[i].sem_num, -adjval);
if (eval == 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 = i - 1; j >= 0; j--) {
if ((sops[j].sem_flg & SEM_UNDO) == 0)
continue;
adjval = sops[j].sem_op;
if (adjval == 0)
continue;
if (semundo_adjust(p, &suptr, semid,
sops[j].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;
#ifdef SEM_DEBUG
printf("eval = %d from semundo_adjust\n", eval);
#endif
return(eval);
} /* loop through the sops */
} /* if (do_undos) */
/* We're definitely done - set the sempid's */
for (i = 0; i < nsops; i++) {
sopptr = &sops[i];
semptr = &semaptr->sem_base[sopptr->sem_num];
semptr->sempid = p->p_pid;
}
/* Do a wakeup if any semaphore was up'd. */
if (do_wakeup) {
#ifdef SEM_DEBUG
printf("semop: doing wakeup\n");
#endif
wakeup((caddr_t)semaptr);
#ifdef SEM_DEBUG
printf("semop: back from wakeup\n");
#endif
}
#ifdef SEM_DEBUG
printf("semop: done\n");
#endif
p->p_retval[0] = 0;
return(0);
}
/*
* Go through the undo structures for this process and apply the adjustments to
* semaphores.
*/
static void
semexit_myhook(p)
struct proc *p;
{
register struct sem_undo *suptr;
register struct sem_undo **supptr;
int did_something;
did_something = 0;
/*
* Go through the chain of undo vectors looking for one
* associated with this process.
*/
for (supptr = &semu_list; (suptr = *supptr) != NULL;
supptr = &suptr->un_next) {
if (suptr->un_proc == p)
break;
}
if (suptr == NULL)
return;
#ifdef SEM_DEBUG
printf("proc @%08x has undo structure with %d entries\n", p,
suptr->un_cnt);
#endif
/*
* 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;
semaptr = &sema[semid];
if ((semaptr->sem_perm.mode & SEM_ALLOC) == 0)
panic("semexit - semid not allocated");
if (semnum >= semaptr->sem_nsems)
panic("semexit - semnum out of range");
#ifdef SEM_DEBUG
printf("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);
#endif
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((caddr_t)semaptr);
#ifdef SEM_DEBUG
printf("semexit: back from wakeup\n");
#endif
}
}
/*
* Deallocate the undo vector.
*/
#ifdef SEM_DEBUG
printf("removing vector\n");
#endif
suptr->un_proc = NULL;
*supptr = suptr->un_next;
}