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uipc_sem.c revision 1.35.8.1
      1  1.35.8.1       mrg /*	$NetBSD: uipc_sem.c,v 1.35.8.1 2012/03/11 01:52:30 mrg Exp $	*/
      2       1.3   thorpej 
      3       1.3   thorpej /*-
      4      1.30     rmind  * Copyright (c) 2011 The NetBSD Foundation, Inc.
      5       1.3   thorpej  * All rights reserved.
      6       1.3   thorpej  *
      7       1.3   thorpej  * This code is derived from software contributed to The NetBSD Foundation
      8      1.30     rmind  * by Mindaugas Rasiukevicius.
      9       1.3   thorpej  *
     10       1.3   thorpej  * Redistribution and use in source and binary forms, with or without
     11       1.3   thorpej  * modification, are permitted provided that the following conditions
     12       1.3   thorpej  * are met:
     13       1.3   thorpej  * 1. Redistributions of source code must retain the above copyright
     14       1.3   thorpej  *    notice, this list of conditions and the following disclaimer.
     15       1.3   thorpej  * 2. Redistributions in binary form must reproduce the above copyright
     16       1.3   thorpej  *    notice, this list of conditions and the following disclaimer in the
     17       1.3   thorpej  *    documentation and/or other materials provided with the distribution.
     18       1.3   thorpej  *
     19       1.3   thorpej  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20       1.3   thorpej  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21       1.3   thorpej  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22       1.3   thorpej  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23       1.3   thorpej  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24       1.3   thorpej  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25       1.3   thorpej  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26       1.3   thorpej  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27       1.3   thorpej  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28       1.3   thorpej  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29       1.3   thorpej  * POSSIBILITY OF SUCH DAMAGE.
     30       1.3   thorpej  */
     31       1.1  christos 
     32       1.1  christos /*
     33       1.1  christos  * Copyright (c) 2002 Alfred Perlstein <alfred (at) FreeBSD.org>
     34       1.1  christos  * All rights reserved.
     35       1.1  christos  *
     36       1.1  christos  * Redistribution and use in source and binary forms, with or without
     37       1.1  christos  * modification, are permitted provided that the following conditions
     38       1.1  christos  * are met:
     39       1.1  christos  * 1. Redistributions of source code must retain the above copyright
     40       1.1  christos  *    notice, this list of conditions and the following disclaimer.
     41       1.1  christos  * 2. Redistributions in binary form must reproduce the above copyright
     42       1.1  christos  *    notice, this list of conditions and the following disclaimer in the
     43       1.1  christos  *    documentation and/or other materials provided with the distribution.
     44       1.1  christos  *
     45       1.1  christos  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     46       1.1  christos  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     47       1.1  christos  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     48       1.1  christos  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     49       1.1  christos  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     50       1.1  christos  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     51       1.1  christos  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     52       1.1  christos  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     53       1.1  christos  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     54       1.1  christos  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     55       1.1  christos  * SUCH DAMAGE.
     56       1.1  christos  */
     57       1.9     lukem 
     58      1.30     rmind /*
     59      1.30     rmind  * Implementation of POSIX semaphore.
     60      1.30     rmind  */
     61      1.30     rmind 
     62       1.9     lukem #include <sys/cdefs.h>
     63  1.35.8.1       mrg __KERNEL_RCSID(0, "$NetBSD: uipc_sem.c,v 1.35.8.1 2012/03/11 01:52:30 mrg Exp $");
     64       1.1  christos 
     65       1.1  christos #include <sys/param.h>
     66       1.1  christos #include <sys/kernel.h>
     67      1.34     rmind 
     68      1.34     rmind #include <sys/atomic.h>
     69       1.1  christos #include <sys/proc.h>
     70       1.1  christos #include <sys/ksem.h>
     71       1.1  christos #include <sys/syscall.h>
     72       1.1  christos #include <sys/stat.h>
     73      1.21        ad #include <sys/kmem.h>
     74       1.1  christos #include <sys/fcntl.h>
     75      1.30     rmind #include <sys/file.h>
     76      1.30     rmind #include <sys/filedesc.h>
     77      1.14      elad #include <sys/kauth.h>
     78      1.27        ad #include <sys/module.h>
     79       1.1  christos #include <sys/mount.h>
     80      1.27        ad #include <sys/syscall.h>
     81       1.1  christos #include <sys/syscallargs.h>
     82      1.27        ad #include <sys/syscallvar.h>
     83       1.1  christos 
     84      1.30     rmind MODULE(MODULE_CLASS_MISC, ksem, NULL);
     85      1.30     rmind 
     86      1.30     rmind #define	SEM_MAX_NAMELEN		14
     87      1.30     rmind #define	SEM_VALUE_MAX		(~0U)
     88       1.1  christos 
     89      1.30     rmind #define	KS_UNLINKED		0x01
     90       1.4   thorpej 
     91      1.30     rmind typedef struct ksem {
     92      1.30     rmind 	LIST_ENTRY(ksem)	ks_entry;	/* global list entry */
     93      1.30     rmind 	kmutex_t		ks_lock;	/* lock on this ksem */
     94      1.30     rmind 	kcondvar_t		ks_cv;		/* condition variable */
     95      1.30     rmind 	u_int			ks_ref;		/* number of references */
     96      1.30     rmind 	u_int			ks_value;	/* current value */
     97      1.30     rmind 	u_int			ks_waiters;	/* number of waiters */
     98      1.30     rmind 	char *			ks_name;	/* name, if named */
     99      1.30     rmind 	size_t			ks_namelen;	/* length of name */
    100      1.30     rmind 	int			ks_flags;	/* for KS_UNLINKED */
    101      1.30     rmind 	mode_t			ks_mode;	/* protection bits */
    102      1.30     rmind 	uid_t			ks_uid;		/* creator uid */
    103      1.30     rmind 	gid_t			ks_gid;		/* creator gid */
    104      1.30     rmind } ksem_t;
    105      1.30     rmind 
    106      1.30     rmind static kmutex_t		ksem_lock	__cacheline_aligned;
    107      1.30     rmind static LIST_HEAD(,ksem)	ksem_head	__cacheline_aligned;
    108      1.34     rmind static u_int		nsems_total	__cacheline_aligned;
    109      1.30     rmind static u_int		nsems		__cacheline_aligned;
    110      1.30     rmind 
    111      1.30     rmind static int		ksem_sysinit(void);
    112      1.30     rmind static int		ksem_sysfini(bool);
    113      1.30     rmind static int		ksem_modcmd(modcmd_t, void *);
    114      1.30     rmind static int		ksem_close_fop(file_t *);
    115      1.30     rmind 
    116      1.30     rmind static const struct fileops semops = {
    117      1.30     rmind 	.fo_read = fbadop_read,
    118      1.30     rmind 	.fo_write = fbadop_write,
    119      1.30     rmind 	.fo_ioctl = fbadop_ioctl,
    120      1.30     rmind 	.fo_fcntl = fnullop_fcntl,
    121      1.30     rmind 	.fo_poll = fnullop_poll,
    122      1.30     rmind 	.fo_stat = fbadop_stat,
    123      1.30     rmind 	.fo_close = ksem_close_fop,
    124      1.30     rmind 	.fo_kqfilter = fnullop_kqfilter,
    125      1.30     rmind 	.fo_restart = fnullop_restart,
    126      1.30     rmind };
    127      1.27        ad 
    128      1.27        ad static const struct syscall_package ksem_syscalls[] = {
    129      1.27        ad 	{ SYS__ksem_init, 0, (sy_call_t *)sys__ksem_init },
    130      1.27        ad 	{ SYS__ksem_open, 0, (sy_call_t *)sys__ksem_open },
    131      1.27        ad 	{ SYS__ksem_unlink, 0, (sy_call_t *)sys__ksem_unlink },
    132      1.27        ad 	{ SYS__ksem_close, 0, (sy_call_t *)sys__ksem_close },
    133      1.27        ad 	{ SYS__ksem_post, 0, (sy_call_t *)sys__ksem_post },
    134      1.27        ad 	{ SYS__ksem_wait, 0, (sy_call_t *)sys__ksem_wait },
    135      1.27        ad 	{ SYS__ksem_trywait, 0, (sy_call_t *)sys__ksem_trywait },
    136      1.27        ad 	{ SYS__ksem_getvalue, 0, (sy_call_t *)sys__ksem_getvalue },
    137      1.27        ad 	{ SYS__ksem_destroy, 0, (sy_call_t *)sys__ksem_destroy },
    138  1.35.8.1       mrg 	{ SYS__ksem_timedwait, 0, (sy_call_t *)sys__ksem_timedwait },
    139      1.27        ad 	{ 0, 0, NULL },
    140      1.27        ad };
    141       1.1  christos 
    142      1.30     rmind static int
    143      1.30     rmind ksem_sysinit(void)
    144       1.3   thorpej {
    145      1.30     rmind 	int error;
    146       1.1  christos 
    147      1.30     rmind 	mutex_init(&ksem_lock, MUTEX_DEFAULT, IPL_NONE);
    148      1.30     rmind 	LIST_INIT(&ksem_head);
    149      1.34     rmind 	nsems_total = 0;
    150      1.34     rmind 	nsems = 0;
    151      1.20        ad 
    152      1.30     rmind 	error = syscall_establish(NULL, ksem_syscalls);
    153      1.30     rmind 	if (error) {
    154      1.30     rmind 		(void)ksem_sysfini(false);
    155       1.3   thorpej 	}
    156      1.30     rmind 	return error;
    157       1.3   thorpej }
    158       1.1  christos 
    159      1.30     rmind static int
    160      1.30     rmind ksem_sysfini(bool interface)
    161       1.1  christos {
    162      1.30     rmind 	int error;
    163       1.1  christos 
    164      1.30     rmind 	if (interface) {
    165      1.30     rmind 		error = syscall_disestablish(NULL, ksem_syscalls);
    166      1.30     rmind 		if (error != 0) {
    167      1.30     rmind 			return error;
    168      1.30     rmind 		}
    169      1.34     rmind 		/*
    170      1.34     rmind 		 * Make sure that no semaphores are in use.  Note: semops
    171      1.34     rmind 		 * must be unused at this point.
    172      1.34     rmind 		 */
    173      1.34     rmind 		if (nsems_total) {
    174      1.30     rmind 			error = syscall_establish(NULL, ksem_syscalls);
    175      1.30     rmind 			KASSERT(error == 0);
    176      1.30     rmind 			return EBUSY;
    177      1.30     rmind 		}
    178       1.3   thorpej 	}
    179      1.30     rmind 	mutex_destroy(&ksem_lock);
    180      1.30     rmind 	return 0;
    181       1.3   thorpej }
    182       1.3   thorpej 
    183      1.30     rmind static int
    184      1.30     rmind ksem_modcmd(modcmd_t cmd, void *arg)
    185       1.3   thorpej {
    186       1.3   thorpej 
    187      1.30     rmind 	switch (cmd) {
    188      1.30     rmind 	case MODULE_CMD_INIT:
    189      1.30     rmind 		return ksem_sysinit();
    190       1.3   thorpej 
    191      1.30     rmind 	case MODULE_CMD_FINI:
    192      1.30     rmind 		return ksem_sysfini(true);
    193       1.1  christos 
    194      1.30     rmind 	default:
    195      1.30     rmind 		return ENOTTY;
    196      1.16   thorpej 	}
    197      1.16   thorpej }
    198      1.16   thorpej 
    199      1.30     rmind static ksem_t *
    200      1.30     rmind ksem_lookup(const char *name)
    201       1.3   thorpej {
    202      1.30     rmind 	ksem_t *ks;
    203       1.3   thorpej 
    204      1.30     rmind 	KASSERT(mutex_owned(&ksem_lock));
    205       1.3   thorpej 
    206      1.30     rmind 	LIST_FOREACH(ks, &ksem_head, ks_entry) {
    207      1.30     rmind 		if (strcmp(ks->ks_name, name) == 0) {
    208      1.30     rmind 			mutex_enter(&ks->ks_lock);
    209      1.30     rmind 			return ks;
    210       1.3   thorpej 		}
    211       1.1  christos 	}
    212      1.30     rmind 	return NULL;
    213       1.1  christos }
    214       1.1  christos 
    215       1.3   thorpej static int
    216      1.30     rmind ksem_perm(lwp_t *l, ksem_t *ks)
    217       1.3   thorpej {
    218      1.30     rmind 	kauth_cred_t uc = l->l_cred;
    219      1.30     rmind 	mode_t mode = ks->ks_mode;
    220       1.3   thorpej 
    221      1.30     rmind 	KASSERT(mutex_owned(&ks->ks_lock));
    222      1.30     rmind 	if ((kauth_cred_geteuid(uc) == ks->ks_uid && (mode & S_IWUSR) != 0) ||
    223      1.30     rmind 	    (kauth_cred_getegid(uc) == ks->ks_gid && (mode & S_IWGRP) != 0) ||
    224      1.30     rmind 	    (mode & S_IWOTH) != 0 ||
    225      1.19      elad 	    kauth_authorize_generic(uc, KAUTH_GENERIC_ISSUSER, NULL) == 0)
    226      1.30     rmind 		return 0;
    227      1.30     rmind 
    228      1.30     rmind 	return EACCES;
    229       1.3   thorpej }
    230       1.3   thorpej 
    231      1.30     rmind /*
    232      1.30     rmind  * ksem_get: get the semaphore from the descriptor.
    233      1.30     rmind  *
    234      1.30     rmind  * => locks the semaphore, if found.
    235      1.30     rmind  * => holds a reference on the file descriptor.
    236      1.30     rmind  */
    237      1.30     rmind static int
    238      1.30     rmind ksem_get(int fd, ksem_t **ksret)
    239      1.13      cube {
    240      1.30     rmind 	ksem_t *ks;
    241      1.30     rmind 	file_t *fp;
    242      1.13      cube 
    243      1.30     rmind 	fp = fd_getfile(fd);
    244  1.35.8.1       mrg 	if (__predict_false(fp == NULL))
    245  1.35.8.1       mrg 		return EINVAL;
    246      1.30     rmind 	if (__predict_false(fp->f_type != DTYPE_SEM)) {
    247      1.30     rmind 		fd_putfile(fd);
    248  1.35.8.1       mrg 		return EINVAL;
    249      1.13      cube 	}
    250      1.30     rmind 	ks = fp->f_data;
    251      1.30     rmind 	mutex_enter(&ks->ks_lock);
    252      1.13      cube 
    253      1.30     rmind 	*ksret = ks;
    254      1.30     rmind 	return 0;
    255       1.1  christos }
    256       1.1  christos 
    257      1.30     rmind /*
    258      1.30     rmind  * ksem_create: allocate and setup a new semaphore structure.
    259      1.30     rmind  */
    260       1.1  christos static int
    261      1.30     rmind ksem_create(lwp_t *l, const char *name, ksem_t **ksret, mode_t mode, u_int val)
    262       1.1  christos {
    263      1.30     rmind 	ksem_t *ks;
    264      1.14      elad 	kauth_cred_t uc;
    265      1.30     rmind 	char *kname;
    266       1.1  christos 	size_t len;
    267       1.1  christos 
    268      1.30     rmind 	/* Pre-check for the limit. */
    269      1.30     rmind 	if (nsems >= ksem_max) {
    270      1.30     rmind 		return ENFILE;
    271      1.30     rmind 	}
    272      1.30     rmind 
    273      1.30     rmind 	if (val > SEM_VALUE_MAX) {
    274      1.30     rmind 		return EINVAL;
    275      1.30     rmind 	}
    276      1.30     rmind 
    277       1.1  christos 	if (name != NULL) {
    278       1.1  christos 		len = strlen(name);
    279       1.1  christos 		if (len > SEM_MAX_NAMELEN) {
    280      1.30     rmind 			return ENAMETOOLONG;
    281       1.1  christos 		}
    282      1.30     rmind 		/* Name must start with a '/' but not contain one. */
    283       1.1  christos 		if (*name != '/' || len < 2 || strchr(name + 1, '/') != NULL) {
    284      1.30     rmind 			return EINVAL;
    285       1.1  christos 		}
    286      1.30     rmind 		kname = kmem_alloc(++len, KM_SLEEP);
    287      1.30     rmind 		strlcpy(kname, name, len);
    288      1.30     rmind 	} else {
    289      1.30     rmind 		kname = NULL;
    290      1.30     rmind 		len = 0;
    291      1.30     rmind 	}
    292      1.30     rmind 
    293      1.30     rmind 	ks = kmem_zalloc(sizeof(ksem_t), KM_SLEEP);
    294      1.30     rmind 	mutex_init(&ks->ks_lock, MUTEX_DEFAULT, IPL_NONE);
    295      1.30     rmind 	cv_init(&ks->ks_cv, "psem");
    296      1.30     rmind 	ks->ks_name = kname;
    297      1.30     rmind 	ks->ks_namelen = len;
    298      1.30     rmind 	ks->ks_mode = mode;
    299      1.30     rmind 	ks->ks_value = val;
    300      1.30     rmind 	ks->ks_ref = 1;
    301      1.30     rmind 
    302      1.30     rmind 	uc = l->l_cred;
    303      1.30     rmind 	ks->ks_uid = kauth_cred_geteuid(uc);
    304      1.30     rmind 	ks->ks_gid = kauth_cred_getegid(uc);
    305      1.30     rmind 
    306      1.34     rmind 	atomic_inc_uint(&nsems_total);
    307      1.30     rmind 	*ksret = ks;
    308      1.30     rmind 	return 0;
    309      1.30     rmind }
    310      1.30     rmind 
    311      1.30     rmind static void
    312      1.30     rmind ksem_free(ksem_t *ks)
    313      1.30     rmind {
    314       1.3   thorpej 
    315      1.34     rmind 	KASSERT(!cv_has_waiters(&ks->ks_cv));
    316      1.34     rmind 
    317      1.30     rmind 	if (ks->ks_name) {
    318      1.30     rmind 		KASSERT(ks->ks_namelen > 0);
    319      1.30     rmind 		kmem_free(ks->ks_name, ks->ks_namelen);
    320      1.13      cube 	}
    321      1.30     rmind 	mutex_destroy(&ks->ks_lock);
    322      1.30     rmind 	cv_destroy(&ks->ks_cv);
    323      1.30     rmind 	kmem_free(ks, sizeof(ksem_t));
    324      1.34     rmind 
    325      1.34     rmind 	atomic_dec_uint(&nsems_total);
    326       1.1  christos }
    327       1.1  christos 
    328       1.1  christos int
    329      1.30     rmind sys__ksem_init(struct lwp *l, const struct sys__ksem_init_args *uap,
    330      1.30     rmind     register_t *retval)
    331       1.1  christos {
    332      1.23       dsl 	/* {
    333       1.1  christos 		unsigned int value;
    334      1.29        ad 		intptr_t *idp;
    335      1.23       dsl 	} */
    336      1.13      cube 
    337      1.13      cube 	return do_ksem_init(l, SCARG(uap, value), SCARG(uap, idp), copyout);
    338      1.13      cube }
    339      1.13      cube 
    340      1.13      cube int
    341      1.30     rmind do_ksem_init(lwp_t *l, u_int val, intptr_t *idp, copyout_t docopyout)
    342      1.13      cube {
    343      1.30     rmind 	proc_t *p = l->l_proc;
    344      1.30     rmind 	ksem_t *ks;
    345      1.30     rmind 	file_t *fp;
    346      1.29        ad 	intptr_t id;
    347      1.30     rmind 	int fd, error;
    348       1.1  christos 
    349      1.30     rmind 	error = fd_allocfile(&fp, &fd);
    350       1.1  christos 	if (error) {
    351      1.30     rmind 		return error;
    352       1.1  christos 	}
    353      1.30     rmind 	fp->f_type = DTYPE_SEM;
    354      1.30     rmind 	fp->f_flag = FREAD | FWRITE;
    355      1.30     rmind 	fp->f_ops = &semops;
    356       1.3   thorpej 
    357      1.30     rmind 	id = (intptr_t)fd;
    358      1.30     rmind 	error = (*docopyout)(&id, idp, sizeof(*idp));
    359      1.30     rmind 	if (error) {
    360      1.30     rmind 		fd_abort(p, fp, fd);
    361      1.30     rmind 		return error;
    362      1.30     rmind 	}
    363       1.3   thorpej 
    364      1.30     rmind 	/* Note the mode does not matter for anonymous semaphores. */
    365      1.30     rmind 	error = ksem_create(l, NULL, &ks, 0, val);
    366      1.30     rmind 	if (error) {
    367      1.30     rmind 		fd_abort(p, fp, fd);
    368      1.30     rmind 		return error;
    369      1.30     rmind 	}
    370      1.30     rmind 	fp->f_data = ks;
    371      1.30     rmind 	fd_affix(p, fp, fd);
    372      1.30     rmind 	return error;
    373       1.1  christos }
    374       1.1  christos 
    375       1.1  christos int
    376      1.30     rmind sys__ksem_open(struct lwp *l, const struct sys__ksem_open_args *uap,
    377      1.30     rmind     register_t *retval)
    378       1.1  christos {
    379      1.23       dsl 	/* {
    380       1.1  christos 		const char *name;
    381       1.1  christos 		int oflag;
    382       1.1  christos 		mode_t mode;
    383       1.1  christos 		unsigned int value;
    384      1.29        ad 		intptr_t *idp;
    385      1.23       dsl 	} */
    386      1.13      cube 
    387      1.13      cube 	return do_ksem_open(l, SCARG(uap, name), SCARG(uap, oflag),
    388      1.13      cube 	    SCARG(uap, mode), SCARG(uap, value), SCARG(uap, idp), copyout);
    389      1.13      cube }
    390      1.13      cube 
    391      1.13      cube int
    392      1.13      cube do_ksem_open(struct lwp *l, const char *semname, int oflag, mode_t mode,
    393      1.29        ad      unsigned int value, intptr_t *idp, copyout_t docopyout)
    394      1.13      cube {
    395       1.1  christos 	char name[SEM_MAX_NAMELEN + 1];
    396      1.30     rmind 	proc_t *p = l->l_proc;
    397      1.30     rmind 	ksem_t *ksnew = NULL, *ks;
    398      1.30     rmind 	file_t *fp;
    399      1.29        ad 	intptr_t id;
    400      1.30     rmind 	int fd, error;
    401       1.1  christos 
    402      1.30     rmind 	error = copyinstr(semname, name, sizeof(name), NULL);
    403      1.30     rmind 	if (error) {
    404      1.30     rmind 		return error;
    405      1.30     rmind 	}
    406      1.30     rmind 	error = fd_allocfile(&fp, &fd);
    407      1.30     rmind 	if (error) {
    408      1.30     rmind 		return error;
    409      1.30     rmind 	}
    410      1.30     rmind 	fp->f_type = DTYPE_SEM;
    411      1.30     rmind 	fp->f_flag = FREAD | FWRITE;
    412      1.30     rmind 	fp->f_ops = &semops;
    413      1.30     rmind 
    414      1.30     rmind 	/*
    415      1.30     rmind 	 * The ID (file descriptor number) can be stored early.
    416      1.30     rmind 	 * Note that zero is a special value for libpthread.
    417      1.30     rmind 	 */
    418      1.30     rmind 	id = (intptr_t)fd;
    419      1.30     rmind 	error = (*docopyout)(&id, idp, sizeof(*idp));
    420      1.30     rmind 	if (error) {
    421      1.30     rmind 		goto err;
    422      1.30     rmind 	}
    423      1.30     rmind 
    424      1.30     rmind 	if (oflag & O_CREAT) {
    425      1.30     rmind 		/* Create a new semaphore. */
    426      1.30     rmind 		error = ksem_create(l, name, &ksnew, mode, value);
    427      1.30     rmind 		if (error) {
    428      1.30     rmind 			goto err;
    429      1.30     rmind 		}
    430      1.30     rmind 		KASSERT(ksnew != NULL);
    431      1.30     rmind 	}
    432       1.1  christos 
    433      1.30     rmind 	/* Lookup for a semaphore with such name. */
    434      1.30     rmind 	mutex_enter(&ksem_lock);
    435      1.30     rmind 	ks = ksem_lookup(name);
    436      1.30     rmind 	if (ks) {
    437      1.30     rmind 		KASSERT(mutex_owned(&ks->ks_lock));
    438      1.30     rmind 		mutex_exit(&ksem_lock);
    439       1.3   thorpej 
    440       1.3   thorpej 		/* Check for exclusive create. */
    441      1.13      cube 		if (oflag & O_EXCL) {
    442      1.30     rmind 			mutex_exit(&ks->ks_lock);
    443      1.30     rmind 			error = EEXIST;
    444      1.30     rmind 			goto err;
    445       1.1  christos 		}
    446       1.1  christos 		/*
    447      1.30     rmind 		 * Verify permissions.  If we can access it,
    448      1.30     rmind 		 * add the reference of this thread.
    449       1.1  christos 		 */
    450      1.15        ad 		error = ksem_perm(l, ks);
    451      1.30     rmind 		if (error == 0) {
    452      1.30     rmind 			ks->ks_ref++;
    453      1.30     rmind 		}
    454      1.30     rmind 		mutex_exit(&ks->ks_lock);
    455       1.1  christos 		if (error) {
    456      1.30     rmind 			goto err;
    457      1.30     rmind 		}
    458      1.30     rmind 	} else {
    459      1.30     rmind 		/* Fail if not found and not creating. */
    460      1.30     rmind 		if ((oflag & O_CREAT) == 0) {
    461      1.30     rmind 			mutex_exit(&ksem_lock);
    462      1.30     rmind 			KASSERT(ksnew == NULL);
    463      1.31     rmind 			error = ENOENT;
    464      1.31     rmind 			goto err;
    465       1.1  christos 		}
    466       1.3   thorpej 
    467      1.30     rmind 		/* Check for the limit locked. */
    468      1.30     rmind 		if (nsems >= ksem_max) {
    469      1.30     rmind 			mutex_exit(&ksem_lock);
    470      1.30     rmind 			error = ENFILE;
    471      1.30     rmind 			goto err;
    472      1.30     rmind 		}
    473       1.3   thorpej 
    474      1.30     rmind 		/*
    475      1.32     rmind 		 * Finally, insert semaphore into the list.
    476      1.30     rmind 		 * Note: it already has the initial reference.
    477      1.30     rmind 		 */
    478      1.30     rmind 		ks = ksnew;
    479      1.30     rmind 		LIST_INSERT_HEAD(&ksem_head, ks, ks_entry);
    480      1.30     rmind 		nsems++;
    481      1.30     rmind 		mutex_exit(&ksem_lock);
    482      1.30     rmind 
    483      1.30     rmind 		ksnew = NULL;
    484      1.30     rmind 	}
    485      1.30     rmind 	KASSERT(ks != NULL);
    486      1.30     rmind 	fp->f_data = ks;
    487      1.30     rmind 	fd_affix(p, fp, fd);
    488      1.30     rmind err:
    489      1.30     rmind 	if (error) {
    490      1.30     rmind 		fd_abort(p, fp, fd);
    491       1.3   thorpej 	}
    492      1.30     rmind 	if (ksnew) {
    493      1.30     rmind 		ksem_free(ksnew);
    494       1.1  christos 	}
    495      1.30     rmind 	return error;
    496      1.30     rmind }
    497       1.1  christos 
    498      1.30     rmind int
    499      1.30     rmind sys__ksem_close(struct lwp *l, const struct sys__ksem_close_args *uap,
    500      1.30     rmind     register_t *retval)
    501      1.30     rmind {
    502      1.30     rmind 	/* {
    503      1.30     rmind 		intptr_t id;
    504      1.30     rmind 	} */
    505      1.33     rmind 	int fd = (int)SCARG(uap, id);
    506      1.33     rmind 
    507      1.33     rmind 	if (fd_getfile(fd) == NULL) {
    508      1.33     rmind 		return EBADF;
    509      1.33     rmind 	}
    510      1.33     rmind 	return fd_close(fd);
    511       1.1  christos }
    512       1.1  christos 
    513      1.30     rmind static int
    514      1.30     rmind ksem_close_fop(file_t *fp)
    515       1.1  christos {
    516      1.30     rmind 	ksem_t *ks = fp->f_data;
    517      1.30     rmind 	bool destroy = false;
    518       1.1  christos 
    519      1.30     rmind 	mutex_enter(&ks->ks_lock);
    520      1.30     rmind 	KASSERT(ks->ks_ref > 0);
    521      1.30     rmind 	if (--ks->ks_ref == 0) {
    522      1.30     rmind 		/*
    523      1.30     rmind 		 * Destroy if the last reference and semaphore is unnamed,
    524      1.30     rmind 		 * or unlinked (for named semaphore).
    525      1.30     rmind 		 */
    526      1.30     rmind 		destroy = (ks->ks_flags & KS_UNLINKED) || (ks->ks_name == NULL);
    527       1.1  christos 	}
    528      1.30     rmind 	mutex_exit(&ks->ks_lock);
    529       1.3   thorpej 
    530      1.30     rmind 	if (destroy) {
    531      1.30     rmind 		ksem_free(ks);
    532      1.30     rmind 	}
    533      1.30     rmind 	return 0;
    534       1.1  christos }
    535       1.1  christos 
    536       1.1  christos int
    537      1.30     rmind sys__ksem_unlink(struct lwp *l, const struct sys__ksem_unlink_args *uap,
    538      1.30     rmind     register_t *retval)
    539       1.1  christos {
    540      1.23       dsl 	/* {
    541       1.1  christos 		const char *name;
    542      1.23       dsl 	} */
    543      1.30     rmind 	char name[SEM_MAX_NAMELEN + 1];
    544      1.30     rmind 	ksem_t *ks;
    545      1.30     rmind 	u_int refcnt;
    546       1.1  christos 	int error;
    547       1.1  christos 
    548      1.30     rmind 	error = copyinstr(SCARG(uap, name), name, sizeof(name), NULL);
    549       1.1  christos 	if (error)
    550       1.1  christos 		return error;
    551       1.1  christos 
    552      1.30     rmind 	mutex_enter(&ksem_lock);
    553      1.30     rmind 	ks = ksem_lookup(name);
    554       1.3   thorpej 	if (ks == NULL) {
    555      1.30     rmind 		mutex_exit(&ksem_lock);
    556      1.30     rmind 		return ENOENT;
    557       1.1  christos 	}
    558      1.30     rmind 	KASSERT(mutex_owned(&ks->ks_lock));
    559       1.3   thorpej 
    560      1.30     rmind 	/* Verify permissions. */
    561      1.30     rmind 	error = ksem_perm(l, ks);
    562      1.30     rmind 	if (error) {
    563      1.30     rmind 		mutex_exit(&ks->ks_lock);
    564      1.30     rmind 		mutex_exit(&ksem_lock);
    565      1.30     rmind 		return error;
    566      1.30     rmind 	}
    567       1.3   thorpej 
    568      1.31     rmind 	/* Remove from the global list. */
    569       1.3   thorpej 	LIST_REMOVE(ks, ks_entry);
    570      1.30     rmind 	nsems--;
    571      1.31     rmind 	mutex_exit(&ksem_lock);
    572       1.3   thorpej 
    573      1.30     rmind 	refcnt = ks->ks_ref;
    574      1.30     rmind 	if (refcnt) {
    575      1.30     rmind 		/* Mark as unlinked, if there are references. */
    576      1.30     rmind 		ks->ks_flags |= KS_UNLINKED;
    577      1.30     rmind 	}
    578      1.30     rmind 	mutex_exit(&ks->ks_lock);
    579       1.3   thorpej 
    580      1.30     rmind 	if (refcnt == 0) {
    581       1.3   thorpej 		ksem_free(ks);
    582      1.30     rmind 	}
    583      1.30     rmind 	return 0;
    584       1.1  christos }
    585       1.1  christos 
    586       1.1  christos int
    587      1.30     rmind sys__ksem_post(struct lwp *l, const struct sys__ksem_post_args *uap,
    588      1.30     rmind     register_t *retval)
    589       1.1  christos {
    590      1.23       dsl 	/* {
    591      1.29        ad 		intptr_t id;
    592      1.23       dsl 	} */
    593      1.30     rmind 	int fd = (int)SCARG(uap, id), error;
    594      1.30     rmind 	ksem_t *ks;
    595       1.1  christos 
    596      1.30     rmind 	error = ksem_get(fd, &ks);
    597      1.30     rmind 	if (error) {
    598      1.30     rmind 		return error;
    599       1.3   thorpej 	}
    600      1.30     rmind 	KASSERT(mutex_owned(&ks->ks_lock));
    601       1.1  christos 	if (ks->ks_value == SEM_VALUE_MAX) {
    602       1.1  christos 		error = EOVERFLOW;
    603       1.3   thorpej 		goto out;
    604       1.1  christos 	}
    605      1.30     rmind 	ks->ks_value++;
    606      1.30     rmind 	if (ks->ks_waiters) {
    607      1.20        ad 		cv_broadcast(&ks->ks_cv);
    608      1.30     rmind 	}
    609      1.30     rmind out:
    610      1.30     rmind 	mutex_exit(&ks->ks_lock);
    611      1.30     rmind 	fd_putfile(fd);
    612      1.30     rmind 	return error;
    613       1.3   thorpej }
    614       1.3   thorpej 
    615  1.35.8.1       mrg int
    616  1.35.8.1       mrg do_ksem_wait(lwp_t *l, intptr_t id, bool try, struct timespec *abstime)
    617       1.3   thorpej {
    618  1.35.8.1       mrg 	int fd = (int)id, error, timeo;
    619      1.30     rmind 	ksem_t *ks;
    620       1.3   thorpej 
    621      1.30     rmind 	error = ksem_get(fd, &ks);
    622      1.30     rmind 	if (error) {
    623      1.30     rmind 		return error;
    624      1.30     rmind 	}
    625      1.30     rmind 	KASSERT(mutex_owned(&ks->ks_lock));
    626       1.3   thorpej 	while (ks->ks_value == 0) {
    627       1.3   thorpej 		ks->ks_waiters++;
    628  1.35.8.1       mrg 		if (!try && abstime != NULL) {
    629  1.35.8.1       mrg 			error = abstimeout2timo(abstime, &timeo);
    630  1.35.8.1       mrg 			if (error != 0)
    631  1.35.8.1       mrg 				goto out;
    632  1.35.8.1       mrg 		} else {
    633  1.35.8.1       mrg 			timeo = 0;
    634  1.35.8.1       mrg 		}
    635  1.35.8.1       mrg 		error = try ? EAGAIN : cv_timedwait_sig(&ks->ks_cv,
    636  1.35.8.1       mrg 		    &ks->ks_lock, timeo);
    637       1.3   thorpej 		ks->ks_waiters--;
    638       1.3   thorpej 		if (error)
    639       1.3   thorpej 			goto out;
    640       1.3   thorpej 	}
    641       1.3   thorpej 	ks->ks_value--;
    642      1.30     rmind out:
    643      1.30     rmind 	mutex_exit(&ks->ks_lock);
    644      1.30     rmind 	fd_putfile(fd);
    645      1.30     rmind 	return error;
    646       1.1  christos }
    647       1.1  christos 
    648       1.1  christos int
    649      1.30     rmind sys__ksem_wait(struct lwp *l, const struct sys__ksem_wait_args *uap,
    650      1.30     rmind     register_t *retval)
    651       1.1  christos {
    652      1.23       dsl 	/* {
    653      1.29        ad 		intptr_t id;
    654      1.23       dsl 	} */
    655       1.1  christos 
    656  1.35.8.1       mrg 	return do_ksem_wait(l, SCARG(uap, id), false, NULL);
    657  1.35.8.1       mrg }
    658  1.35.8.1       mrg 
    659  1.35.8.1       mrg int
    660  1.35.8.1       mrg sys__ksem_timedwait(struct lwp *l, const struct sys__ksem_timedwait_args *uap,
    661  1.35.8.1       mrg     register_t *retval)
    662  1.35.8.1       mrg {
    663  1.35.8.1       mrg 	/* {
    664  1.35.8.1       mrg 		intptr_t id;
    665  1.35.8.1       mrg 		const struct timespec *abstime;
    666  1.35.8.1       mrg 	} */
    667  1.35.8.1       mrg 	struct timespec ts;
    668  1.35.8.1       mrg 	int error;
    669  1.35.8.1       mrg 
    670  1.35.8.1       mrg 	error = copyin(SCARG(uap, abstime), &ts, sizeof(ts));
    671  1.35.8.1       mrg 	if (error != 0)
    672  1.35.8.1       mrg 		return error;
    673  1.35.8.1       mrg 
    674  1.35.8.1       mrg 	if (ts.tv_sec < 0 || ts.tv_nsec < 0 || ts.tv_nsec >= 1000000000)
    675  1.35.8.1       mrg 		return EINVAL;
    676  1.35.8.1       mrg 
    677  1.35.8.1       mrg 	error = do_ksem_wait(l, SCARG(uap, id), false, &ts);
    678  1.35.8.1       mrg 	if (error == EWOULDBLOCK)
    679  1.35.8.1       mrg 		error = ETIMEDOUT;
    680  1.35.8.1       mrg 	return error;
    681       1.1  christos }
    682       1.1  christos 
    683       1.1  christos int
    684      1.30     rmind sys__ksem_trywait(struct lwp *l, const struct sys__ksem_trywait_args *uap,
    685      1.30     rmind     register_t *retval)
    686       1.1  christos {
    687      1.23       dsl 	/* {
    688      1.29        ad 		intptr_t id;
    689      1.23       dsl 	} */
    690       1.1  christos 
    691  1.35.8.1       mrg 	return do_ksem_wait(l, SCARG(uap, id), true, NULL);
    692       1.1  christos }
    693       1.1  christos 
    694       1.1  christos int
    695      1.30     rmind sys__ksem_getvalue(struct lwp *l, const struct sys__ksem_getvalue_args *uap,
    696      1.30     rmind     register_t *retval)
    697       1.1  christos {
    698      1.23       dsl 	/* {
    699      1.29        ad 		intptr_t id;
    700       1.1  christos 		unsigned int *value;
    701      1.23       dsl 	} */
    702      1.30     rmind 	int fd = (int)SCARG(uap, id), error;
    703      1.30     rmind 	ksem_t *ks;
    704       1.1  christos 	unsigned int val;
    705       1.1  christos 
    706      1.30     rmind 	error = ksem_get(fd, &ks);
    707      1.30     rmind 	if (error) {
    708      1.30     rmind 		return error;
    709      1.30     rmind 	}
    710      1.30     rmind 	KASSERT(mutex_owned(&ks->ks_lock));
    711       1.1  christos 	val = ks->ks_value;
    712      1.30     rmind 	mutex_exit(&ks->ks_lock);
    713      1.30     rmind 	fd_putfile(fd);
    714       1.3   thorpej 
    715      1.30     rmind 	return copyout(&val, SCARG(uap, value), sizeof(val));
    716       1.1  christos }
    717       1.1  christos 
    718       1.1  christos int
    719      1.30     rmind sys__ksem_destroy(struct lwp *l, const struct sys__ksem_destroy_args *uap,
    720      1.30     rmind     register_t *retval)
    721       1.1  christos {
    722      1.23       dsl 	/* {
    723      1.29        ad 		intptr_t id;
    724      1.23       dsl 	} */
    725      1.30     rmind 	int fd = (int)SCARG(uap, id), error;
    726      1.30     rmind 	ksem_t *ks;
    727       1.1  christos 
    728      1.30     rmind 	error = ksem_get(fd, &ks);
    729      1.30     rmind 	if (error) {
    730      1.30     rmind 		return error;
    731       1.3   thorpej 	}
    732      1.30     rmind 	KASSERT(mutex_owned(&ks->ks_lock));
    733       1.3   thorpej 
    734      1.30     rmind 	/* Operation is only for unnamed semaphores. */
    735       1.3   thorpej 	if (ks->ks_name != NULL) {
    736      1.30     rmind 		error = EINVAL;
    737      1.30     rmind 		goto out;
    738       1.3   thorpej 	}
    739      1.30     rmind 	/* Cannot destroy if there are waiters. */
    740       1.3   thorpej 	if (ks->ks_waiters) {
    741      1.30     rmind 		error = EBUSY;
    742      1.30     rmind 		goto out;
    743       1.3   thorpej 	}
    744      1.30     rmind out:
    745      1.30     rmind 	mutex_exit(&ks->ks_lock);
    746      1.30     rmind 	if (error) {
    747      1.32     rmind 		fd_putfile(fd);
    748      1.27        ad 		return error;
    749      1.27        ad 	}
    750      1.32     rmind 	return fd_close(fd);
    751      1.22     rmind }
    752