svn commit: r298656 - head/sys/kern

Conrad Meyer cem at FreeBSD.org
Tue Apr 26 18:46:27 UTC 2016


The sbuf use here was fine before.

Best,
Conrad

On Tue, Apr 26, 2016 at 11:17 AM, Jamie Gritton <jamie at freebsd.org> wrote:

> Author: jamie
> Date: Tue Apr 26 18:17:44 2016
> New Revision: 298656
> URL: https://svnweb.freebsd.org/changeset/base/298656
>
> Log:
>   Redo the changes to the SYSV IPC sysctl functions from r298585, so they
>   don't (mis)use sbufs.
>
>   PR:           48471
>
> Modified:
>   head/sys/kern/sysv_msg.c
>   head/sys/kern/sysv_sem.c
>   head/sys/kern/sysv_shm.c
>
> Modified: head/sys/kern/sysv_msg.c
>
> ==============================================================================
> --- head/sys/kern/sysv_msg.c    Tue Apr 26 18:11:45 2016        (r298655)
> +++ head/sys/kern/sysv_msg.c    Tue Apr 26 18:17:44 2016        (r298656)
> @@ -65,7 +65,6 @@ __FBSDID("$FreeBSD$");
>  #include <sys/mount.h>
>  #include <sys/msg.h>
>  #include <sys/racct.h>
> -#include <sys/sbuf.h>
>  #include <sys/sx.h>
>  #include <sys/syscall.h>
>  #include <sys/syscallsubr.h>
> @@ -1423,38 +1422,28 @@ sys_msgrcv(td, uap)
>  static int
>  sysctl_msqids(SYSCTL_HANDLER_ARGS)
>  {
> -       struct sbuf sb;
> -       struct msqid_kernel tmp, empty;
> -       struct msqid_kernel *msqkptr;
> -       struct prison *rpr;
> +       struct msqid_kernel tmsqk;
> +       struct prison *pr, *rpr;
>         int error, i;
>
> -       error = sysctl_wire_old_buffer(req, 0);
> -       if (error != 0)
> -               goto done;
> +       pr = req->td->td_ucred->cr_prison;
>         rpr = msg_find_prison(req->td->td_ucred);
> -       sbuf_new_for_sysctl(&sb, NULL, sizeof(struct msqid_kernel) *
> -           msginfo.msgmni, req);
> -
> -       bzero(&empty, sizeof(empty));
> +       error = 0;
>         for (i = 0; i < msginfo.msgmni; i++) {
> -               msqkptr = &msqids[i];
> -               if (msqkptr->u.msg_qbytes == 0 || rpr == NULL ||
> -                   msq_prison_cansee(rpr, msqkptr) != 0) {
> -                       msqkptr = ∅
> -               } else if (req->td->td_ucred->cr_prison !=
> -                   msqkptr->cred->cr_prison) {
> -                       bcopy(msqkptr, &tmp, sizeof(tmp));
> -                       msqkptr = &tmp;
> -                       msqkptr->u.msg_perm.key = IPC_PRIVATE;
> +               mtx_lock(&msq_mtx);
> +               if (msqids[i].u.msg_qbytes == 0 || rpr == NULL ||
> +                   msq_prison_cansee(rpr, &msqids[i]) != 0)
> +                       bzero(&tmsqk, sizeof(tmsqk));
> +               else {
> +                       tmsqk = msqids[i];
> +                       if (tmsqk.cred->cr_prison != pr)
> +                               tmsqk.u.msg_perm.key = IPC_PRIVATE;
>                 }
> -
> -               sbuf_bcat(&sb, msqkptr, sizeof(*msqkptr));
> +               mtx_unlock(&msq_mtx);
> +               error = SYSCTL_OUT(req, &tmsqk, sizeof(tmsqk));
> +               if (error != 0)
> +                       break;
>         }
> -       error = sbuf_finish(&sb);
> -       sbuf_delete(&sb);
> -
> -done:
>         return (error);
>  }
>
> @@ -1470,7 +1459,8 @@ SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz,
>      "Size of a message segment");
>  SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
>      "Number of message segments");
> -SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLTYPE_OPAQUE | CTLFLAG_RD,
> +SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids,
> +    CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
>      NULL, 0, sysctl_msqids, "", "Message queue IDs");
>
>  static int
>
> Modified: head/sys/kern/sysv_sem.c
>
> ==============================================================================
> --- head/sys/kern/sysv_sem.c    Tue Apr 26 18:11:45 2016        (r298655)
> +++ head/sys/kern/sysv_sem.c    Tue Apr 26 18:17:44 2016        (r298656)
> @@ -52,7 +52,6 @@ __FBSDID("$FreeBSD$");
>  #include <sys/module.h>
>  #include <sys/mutex.h>
>  #include <sys/racct.h>
> -#include <sys/sbuf.h>
>  #include <sys/sem.h>
>  #include <sys/sx.h>
>  #include <sys/syscall.h>
> @@ -220,7 +219,8 @@ SYSCTL_INT(_kern_ipc, OID_AUTO, semvmx,
>      "Semaphore maximum value");
>  SYSCTL_INT(_kern_ipc, OID_AUTO, semaem, CTLFLAG_RWTUN, &seminfo.semaem, 0,
>      "Adjust on exit max value");
> -SYSCTL_PROC(_kern_ipc, OID_AUTO, sema, CTLTYPE_OPAQUE | CTLFLAG_RD,
> +SYSCTL_PROC(_kern_ipc, OID_AUTO, sema,
> +    CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
>      NULL, 0, sysctl_sema, "", "Semaphore id pool");
>
>  static struct syscall_helper_data sem_syscalls[] = {
> @@ -1465,38 +1465,28 @@ semexit_myhook(void *arg, struct proc *p
>  static int
>  sysctl_sema(SYSCTL_HANDLER_ARGS)
>  {
> -       struct prison *rpr;
> -       struct sbuf sb;
> -       struct semid_kernel tmp, empty;
> -       struct semid_kernel *semakptr;
> +       struct prison *pr, *rpr;
> +       struct semid_kernel tsemak;
>         int error, i;
>
> -       error = sysctl_wire_old_buffer(req, 0);
> -       if (error != 0)
> -               goto done;
> +       pr = req->td->td_ucred->cr_prison;
>         rpr = sem_find_prison(req->td->td_ucred);
> -       sbuf_new_for_sysctl(&sb, NULL, sizeof(struct semid_kernel) *
> -           seminfo.semmni, req);
> -
> -       bzero(&empty, sizeof(empty));
> +       error = 0;
>         for (i = 0; i < seminfo.semmni; i++) {
> -               semakptr = &sema[i];
> -               if ((semakptr->u.sem_perm.mode & SEM_ALLOC) == 0 ||
> -                   rpr == NULL || sem_prison_cansee(rpr, semakptr) != 0) {
> -                       semakptr = ∅
> -               } else if (req->td->td_ucred->cr_prison !=
> -                   semakptr->cred->cr_prison) {
> -                       bcopy(semakptr, &tmp, sizeof(tmp));
> -                       semakptr = &tmp;
> -                       semakptr->u.sem_perm.key = IPC_PRIVATE;
> +               mtx_lock(&sema_mtx[i]);
> +               if ((sema[i].u.sem_perm.mode & SEM_ALLOC) == 0 ||
> +                   rpr == NULL || sem_prison_cansee(rpr, &sema[i]) != 0)
> +                       bzero(&tsemak, sizeof(tsemak));
> +               else {
> +                       tsemak = sema[i];
> +                       if (tsemak.cred->cr_prison != pr)
> +                               tsemak.u.sem_perm.key = IPC_PRIVATE;
>                 }
> -
> -               sbuf_bcat(&sb, semakptr, sizeof(*semakptr));
> +               mtx_unlock(&sema_mtx[i]);
> +               error = SYSCTL_OUT(req, &tsemak, sizeof(tsemak));
> +               if (error != 0)
> +                       break;
>         }
> -       error = sbuf_finish(&sb);
> -       sbuf_delete(&sb);
> -
> -done:
>         return (error);
>  }
>
>
> Modified: head/sys/kern/sysv_shm.c
>
> ==============================================================================
> --- head/sys/kern/sysv_shm.c    Tue Apr 26 18:11:45 2016        (r298655)
> +++ head/sys/kern/sysv_shm.c    Tue Apr 26 18:17:44 2016        (r298656)
> @@ -80,7 +80,6 @@ __FBSDID("$FreeBSD$");
>  #include <sys/racct.h>
>  #include <sys/resourcevar.h>
>  #include <sys/rwlock.h>
> -#include <sys/sbuf.h>
>  #include <sys/stat.h>
>  #include <sys/syscall.h>
>  #include <sys/syscallsubr.h>
> @@ -1009,40 +1008,28 @@ shmunload(void)
>  static int
>  sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
>  {
> -       struct prison *rpr;
> -       struct sbuf sb;
> -       struct shmid_kernel tmp, empty;
> -       struct shmid_kernel *shmseg;
> +       struct shmid_kernel tshmseg;
> +       struct prison *pr, *rpr;
>         int error, i;
>
>         SYSVSHM_LOCK();
> -
> -       error = sysctl_wire_old_buffer(req, 0);
> -       if (error != 0)
> -               goto done;
> +       pr = req->td->td_ucred->cr_prison;
>         rpr = shm_find_prison(req->td->td_ucred);
> -       sbuf_new_for_sysctl(&sb, NULL, shmalloced * sizeof(shmsegs[0]),
> req);
> -
> -       bzero(&empty, sizeof(empty));
> -       empty.u.shm_perm.mode = SHMSEG_FREE;
> +       error = 0;
>         for (i = 0; i < shmalloced; i++) {
> -               shmseg = &shmsegs[i];
> -               if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
> +               if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
>                     rpr == NULL || shm_prison_cansee(rpr, &shmsegs[i]) !=
> 0) {
> -                       shmseg = ∅
> -               } else if (req->td->td_ucred->cr_prison !=
> -                   shmseg->cred->cr_prison) {
> -                       bcopy(shmseg, &tmp, sizeof(tmp));
> -                       shmseg = &tmp;
> -                       shmseg->u.shm_perm.key = IPC_PRIVATE;
> +                       bzero(&tshmseg, sizeof(tshmseg));
> +                       tshmseg.u.shm_perm.mode = SHMSEG_FREE;
> +               } else {
> +                       tshmseg = shmsegs[i];
> +                       if (tshmseg.cred->cr_prison != pr)
> +                               tshmseg.u.shm_perm.key = IPC_PRIVATE;
>                 }
> -
> -               sbuf_bcat(&sb, shmseg, sizeof(*shmseg));
> +               error = SYSCTL_OUT(req, &tshmseg, sizeof(tshmseg));
> +               if (error != 0)
> +                       break;
>         }
> -       error = sbuf_finish(&sb);
> -       sbuf_delete(&sb);
> -
> -done:
>         SYSVSHM_UNLOCK();
>         return (error);
>  }
>
>


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