sysv_shm.c File Reference

#include <sys/cdefs.h>
#include "opt_compat.h"
#include "opt_sysvipc.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/shm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/jail.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_object.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>

Include dependency graph for sysv_shm.c:

Go to the source code of this file.

Data Structures
struct	shmmap_state
struct	shmdt_args
struct	shmat_args
struct	shmctl_args
struct	shmget_args

Macros
#define	SHMSEG_FREE   0x0200
#define	SHMSEG_REMOVED   0x0400
#define	SHMSEG_ALLOCATED   0x0800
#define	SHMSEG_WANTED   0x1000
#define	SHMMAXPGS   131072 /* Note: sysv shared memory is swap backed. */
#define	SHMMAX   (SHMMAXPGS*PAGE_SIZE)
#define	SHMMIN   1
#define	SHMMNI   192
#define	SHMSEG   128
#define	SHMALL   (SHMMAXPGS)

Functions
	__FBSDID ("$BSDSUniX$")
	FEATURE (sysv_shm,"System V shared memory segments support")
static	MALLOC_DEFINE (M_SHM,"shm","SVID compatible shared memory segments")
static int	shmget_allocate_segment (struct thread *td, struct shmget_args *uap, int mode)
static int	shmget_existing (struct thread *td, struct shmget_args *uap, int mode, int segnum)
static void	shm_deallocate_segment (struct shmid_kernel *)
static int	shm_find_segment_by_key (key_t)
static struct shmid_kernel *	shm_find_segment_by_shmid (int)
static struct shmid_kernel *	shm_find_segment_by_shmidx (int)
static int	shm_delete_mapping (struct vmspace *vm, struct shmmap_state *)
static void	shmrealloc (void)
static int	shminit (void)
static int	sysvshm_modload (struct module *, int, void *)
static int	shmunload (void)
static void	shmexit_myhook (struct vmspace *vm)
static void	shmfork_myhook (struct proc *p1, struct proc *p2)
static int	sysctl_shmsegs (SYSCTL_HANDLER_ARGS)
	SYSCTL_ULONG (_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW,&shminfo.shmmax, 0,"Maximum shared memory segment size")
	SYSCTL_ULONG (_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW,&shminfo.shmmin, 0,"Minimum shared memory segment size")
	SYSCTL_ULONG (_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN,&shminfo.shmmni, 0,"Number of shared memory identifiers")
	SYSCTL_ULONG (_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN,&shminfo.shmseg, 0,"Number of segments per process")
	SYSCTL_ULONG (_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW,&shminfo.shmall, 0,"Maximum number of pages available for shared memory")
	SYSCTL_INT (_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,&shm_use_phys, 0,"Enable/Disable locking of shared memory pages in core")
	SYSCTL_INT (_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,&shm_allow_removed, 0,"Enable/Disable attachment to attached segments marked for removal")
	SYSCTL_PROC (_kern_ipc, OID_AUTO, shmsegs, CTLTYPE_OPAQUE|CTLFLAG_RD, NULL, 0, sysctl_shmsegs,"","Current number of shared memory segments allocated")
int	sys_shmdt (struct thread *td, struct shmdt_args *uap)
int	kern_shmat (struct thread *td, int shmid, const void *shmaddr, int shmflg)
int	sys_shmat (struct thread *td, struct shmat_args *uap)
int	kern_shmctl (struct thread *td, int shmid, int cmd, void *buf, size_t *bufsz)
int	sys_shmctl (struct thread *td, struct shmctl_args *uap)
int	sys_shmget (struct thread *td, struct shmget_args *uap)
	DECLARE_MODULE (sysvshm, sysvshm_mod, SI_SUB_SYSV_SHM, SI_ORDER_FIRST)
	MODULE_VERSION (sysvshm, 1)

Variables
static int	shm_last_free
static int	shm_nused
static int	shmalloced
vm_size_t	shm_committed
static struct shmid_kernel *	shmsegs
struct shminfo	shminfo
static int	shm_use_phys
static int	shm_allow_removed
static struct syscall_helper_data	shm_syscalls []
static moduledata_t	sysvshm_mod

Macro Definition Documentation

#define SHMALL   (SHMMAXPGS)

Definition at line 154 of file sysv_shm.c.

#define SHMMAX   (SHMMAXPGS*PAGE_SIZE)

Definition at line 142 of file sysv_shm.c.

#define SHMMAXPGS   131072 /* Note: sysv shared memory is swap backed. */

Definition at line 139 of file sysv_shm.c.

#define SHMMIN   1

Definition at line 145 of file sysv_shm.c.

#define SHMMNI   192

Definition at line 148 of file sysv_shm.c.

#define SHMSEG   128

Definition at line 151 of file sysv_shm.c.

#define SHMSEG_ALLOCATED   0x0800

Definition at line 110 of file sysv_shm.c.

Referenced by shm_find_segment_by_key(), shm_find_segment_by_shmid(), shm_find_segment_by_shmidx(), and shmget_allocate_segment().

#define SHMSEG_FREE   0x0200

Definition at line 108 of file sysv_shm.c.

Referenced by shm_deallocate_segment(), shmget_allocate_segment(), shminit(), shmrealloc(), and shmunload().

#define SHMSEG_REMOVED   0x0400

Definition at line 109 of file sysv_shm.c.

Referenced by kern_shmctl(), shm_delete_mapping(), shm_find_segment_by_shmid(), shm_find_segment_by_shmidx(), shmget_allocate_segment(), and shmget_existing().

#define SHMSEG_WANTED   0x1000

Definition at line 111 of file sysv_shm.c.

Referenced by shmget_allocate_segment(), and shmget_existing().

Function Documentation

__FBSDID

(

"$BSDSUniX$"

)

DECLARE_MODULE	(	sysvshm	,
		sysvshm_mod	,
		SI_SUB_SYSV_SHM	,
		SI_ORDER_FIRST
	)

FEATURE	(	sysv_shm	,
		"System V shared memory segments support"
	)

int kern_shmat	(	struct thread *	td,
		int	shmid,
		const void *	shmaddr,
		int	shmflg
	)

Definition at line 337 of file sysv_shm.c.

References free(), Giant, ipcperm(), lim_max(), malloc(), prison_allow(), shm_find_segment_by_shmid(), shmmap_state::shmid, shminfo, time_second, and shmmap_state::va.

Referenced by sys_shmat().

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int kern_shmctl	(	struct thread *	td,
		int	shmid,
		int	cmd,
		void *	buf,
		size_t *	bufsz
	)

Definition at line 456 of file sysv_shm.c.

References Giant, ipcperm(), prison_allow(), shm_deallocate_segment(), shm_find_segment_by_shmid(), shm_find_segment_by_shmidx(), shm_last_free, shm_nused, shmalloced, shminfo, SHMSEG_REMOVED, and time_second.

Referenced by sys_shmctl().

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static MALLOC_DEFINE ( M_SHM  , "shm"  , "SVID compatible shared memory segments"    )

static

MODULE_VERSION	(	sysvshm	,
		1
	)

static void shm_deallocate_segment ( struct shmid_kernel *  shmseg )

static

Definition at line 234 of file sysv_shm.c.

References crfree(), racct_sub_cred(), shm_committed, shm_nused, and SHMSEG_FREE.

Referenced by kern_shmctl(), and shm_delete_mapping().

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static int shm_delete_mapping ( struct vmspace *  vm, struct shmmap_state *  shmmap_s  )

static

Definition at line 257 of file sysv_shm.c.

References result, shm_deallocate_segment(), shm_last_free, shmmap_state::shmid, SHMSEG_REMOVED, shmsegs, time_second, and shmmap_state::va.

Referenced by shmexit_myhook(), and sys_shmdt().

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static int shm_find_segment_by_key ( key_t  key )

static

Definition at line 188 of file sysv_shm.c.

References shmalloced, SHMSEG_ALLOCATED, and shmsegs.

Referenced by sys_shmget().

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static struct shmid_kernel * shm_find_segment_by_shmid ( int  shmid )

static

Definition at line 201 of file sysv_shm.c.

References shm_allow_removed, shmalloced, SHMSEG_ALLOCATED, SHMSEG_REMOVED, and shmsegs.

Referenced by kern_shmat(), and kern_shmctl().

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static struct shmid_kernel * shm_find_segment_by_shmidx ( int  segnum )

static

Definition at line 219 of file sysv_shm.c.

References shm_allow_removed, shmalloced, SHMSEG_ALLOCATED, SHMSEG_REMOVED, and shmsegs.

Referenced by kern_shmctl().

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static void shmexit_myhook ( struct vmspace *  vm )

static

Definition at line 815 of file sysv_shm.c.

References free(), Giant, shm_delete_mapping(), shmmap_state::shmid, and shminfo.

Referenced by shminit().

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static void shmfork_myhook ( struct proc *  p1, struct proc *  p2  )

static

Definition at line 796 of file sysv_shm.c.

References Giant, malloc(), shmmap_state::shmid, shminfo, and shmsegs.

Referenced by shminit().

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static int shmget_allocate_segment ( struct thread *  td, struct shmget_args *  uap, int  mode  )

static

Definition at line 653 of file sysv_shm.c.

References crhold(), shmget_args::key, racct_add(), racct_sub(), shm_committed, shm_last_free, shm_nused, shm_use_phys, shmalloced, shminfo, shmrealloc(), SHMSEG_ALLOCATED, SHMSEG_FREE, SHMSEG_REMOVED, SHMSEG_WANTED, shmsegs, shmget_args::size, time_second, and wakeup().

Referenced by sys_shmget().

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static int shmget_existing ( struct thread *  td, struct shmget_args *  uap, int  mode, int  segnum  )

static

Definition at line 617 of file sysv_shm.c.

References shmget_args::shmflg, SHMSEG_REMOVED, SHMSEG_WANTED, shmsegs, and shmget_args::size.

Referenced by sys_shmget().

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static int shminit ( void  )

static

Definition at line 894 of file sysv_shm.c.

References malloc(), printf(), shm_committed, shm_last_free, shm_nused, shm_syscalls, shm_use_phys, shmalloced, shmexit_hook, shmexit_myhook(), shmfork_hook, shmfork_myhook(), shminfo, SHMSEG_FREE, shmsegs, and syscall_helper_register().

Referenced by sysvshm_modload().

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static void shmrealloc ( void  )

static

Definition at line 833 of file sysv_shm.c.

References free(), malloc(), shmalloced, shminfo, SHMSEG_FREE, and shmsegs.

Referenced by shmget_allocate_segment().

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static int shmunload ( void  )

static

Definition at line 943 of file sysv_shm.c.

References free(), shm_nused, shm_syscalls, shmalloced, shmexit_hook, shmfork_hook, SHMSEG_FREE, shmsegs, and syscall_helper_unregister().

Referenced by sysvshm_modload().

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int sys_shmat	(	struct thread *	td,
		struct shmat_args *	uap
	)

Definition at line 448 of file sysv_shm.c.

References kern_shmat(), shmat_args::shmaddr, shmat_args::shmflg, and shmat_args::shmid.

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int sys_shmctl	(	struct thread *	td,
		struct shmctl_args *	uap
	)

Definition at line 573 of file sysv_shm.c.

References shmctl_args::buf, shmctl_args::cmd, kern_shmctl(), and shmctl_args::shmid.

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int sys_shmdt	(	struct thread *	td,
		struct shmdt_args *	uap
	)

Definition at line 287 of file sysv_shm.c.

References Giant, prison_allow(), shm_delete_mapping(), shmdt_args::shmaddr, shmmap_state::shmid, shminfo, shmsegs, and shmmap_state::va.

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int sys_shmget	(	struct thread *	td,
		struct shmget_args *	uap
	)

Definition at line 764 of file sysv_shm.c.

References Giant, shmget_args::key, mode, prison_allow(), shm_find_segment_by_key(), shmget_args::shmflg, shmget_allocate_segment(), and shmget_existing().

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SYSCTL_INT	(	_kern_ipc	,
		OID_AUTO	,
		shm_use_phys	,
		CTLFLAG_RW	,
		&	shm_use_phys,
		0	,
		"Enable/Disable locking of shared memory pages in core"
	)

SYSCTL_INT	(	_kern_ipc	,
		OID_AUTO	,
		shm_allow_removed	,
		CTLFLAG_RW	,
		&	shm_allow_removed,
		0	,
		"Enable/Disable attachment to attached segments marked for removal"
	)

SYSCTL_PROC	(	_kern_ipc	,
		OID_AUTO	,
		shmsegs	,
		CTLTYPE_OPAQUE|	CTLFLAG_RD,
		NULL	,
		0	,
		sysctl_shmsegs	,
		""	,
		"Current number of shared memory segments allocated"
	)

static int sysctl_shmsegs ( SYSCTL_HANDLER_ARGS  )

static

Definition at line 974 of file sysv_shm.c.

References shmalloced, and shmsegs.

SYSCTL_ULONG	(	_kern_ipc	,
		OID_AUTO	,
		shmmax	,
		CTLFLAG_RW	,
		&shminfo.	shmmax,
		0	,
		"Maximum shared memory segment size"
	)

SYSCTL_ULONG	(	_kern_ipc	,
		OID_AUTO	,
		shmmin	,
		CTLFLAG_RW	,
		&shminfo.	shmmin,
		0	,
		"Minimum shared memory segment size"
	)

SYSCTL_ULONG	(	_kern_ipc	,
		OID_AUTO	,
		shmmni	,
		CTLFLAG_RDTUN	,
		&shminfo.	shmmni,
		0	,
		"Number of shared memory identifiers"
	)

SYSCTL_ULONG	(	_kern_ipc	,
		OID_AUTO	,
		shmseg	,
		CTLFLAG_RDTUN	,
		&shminfo.	shmseg,
		0	,
		"Number of segments per process"
	)

SYSCTL_ULONG	(	_kern_ipc	,
		OID_AUTO	,
		shmall	,
		CTLFLAG_RW	,
		&shminfo.	shmall,
		0	,
		"Maximum number of pages available for shared memory"
	)

static int sysvshm_modload ( struct module *  module, int  cmd, void *  arg  )

static

Definition at line 1388 of file sysv_shm.c.

References shminit(), and shmunload().

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Variable Documentation

int shm_allow_removed

static

Definition at line 166 of file sysv_shm.c.

Referenced by shm_find_segment_by_shmid(), and shm_find_segment_by_shmidx().

vm_size_t shm_committed

Definition at line 114 of file sysv_shm.c.

Referenced by shm_deallocate_segment(), shmget_allocate_segment(), and shminit().

int shm_last_free

static

Definition at line 113 of file sysv_shm.c.

Referenced by kern_shmctl(), shm_delete_mapping(), shmget_allocate_segment(), and shminit().

int shm_nused

static

Definition at line 113 of file sysv_shm.c.

Referenced by kern_shmctl(), shm_deallocate_segment(), shmget_allocate_segment(), shminit(), and shmunload().

struct syscall_helper_data shm_syscalls[]

static

Initial value:

= {
        SYSCALL_INIT_HELPER(shmat),
        SYSCALL_INIT_HELPER(shmctl),
        SYSCALL_INIT_HELPER(shmdt),
        SYSCALL_INIT_HELPER(shmget),







        SYSCALL_INIT_LAST
}

Definition at line 856 of file sysv_shm.c.

Referenced by shminit(), and shmunload().

int shm_use_phys

static

Definition at line 165 of file sysv_shm.c.

Referenced by shmget_allocate_segment(), and shminit().

int shmalloced

static

Definition at line 113 of file sysv_shm.c.

Referenced by kern_shmctl(), shm_find_segment_by_key(), shm_find_segment_by_shmid(), shm_find_segment_by_shmidx(), shmget_allocate_segment(), shminit(), shmrealloc(), shmunload(), and sysctl_shmsegs().

struct shminfo shminfo

Initial value:

= {
        SHMMAX,
        SHMMIN,
        SHMMNI,
        SHMSEG,
        SHMALL
}

Definition at line 157 of file sysv_shm.c.

Referenced by kern_shmat(), kern_shmctl(), shmexit_myhook(), shmfork_myhook(), shmget_allocate_segment(), shminit(), shmrealloc(), and sys_shmdt().

struct shmid_kernel* shmsegs

static

Definition at line 115 of file sysv_shm.c.

Referenced by shm_delete_mapping(), shm_find_segment_by_key(), shm_find_segment_by_shmid(), shm_find_segment_by_shmidx(), shmfork_myhook(), shmget_allocate_segment(), shmget_existing(), shminit(), shmrealloc(), shmunload(), sys_shmdt(), and sysctl_shmsegs().

moduledata_t sysvshm_mod

static

Initial value:

= {
        "sysvshm",
        &sysvshm_modload,
        NULL
}

Definition at line 1410 of file sysv_shm.c.