xnu-1699.22.73.tar.gz

[apple/xnu.git] / bsd / kern / sys_pipe.c

diff --git a/bsd/kern/sys_pipe.c b/bsd/kern/sys_pipe.c
index f86ad5a11775f6698b2740c22f2e8d159b678bb7..c374ea07e6dd3d32e761034a7c8417b652327e05 100644 (file)
--- a/bsd/kern/sys_pipe.c
+++ b/bsd/kern/sys_pipe.c
@@ -231,17 +231,17 @@ int maxpipekva = 1024 * 1024 * 16;
 #if PIPE_SYSCTLS
 SYSCTL_DECL(_kern_ipc);
 
-SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RD,
+SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RD|CTLFLAG_LOCKED,
           &maxpipekva, 0, "Pipe KVA limit");
-SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekvawired, CTLFLAG_RW,
+SYSCTL_INT(_kern_ipc, OID_AUTO, maxpipekvawired, CTLFLAG_RW|CTLFLAG_LOCKED,
           &maxpipekvawired, 0, "Pipe KVA wired limit");
-SYSCTL_INT(_kern_ipc, OID_AUTO, pipes, CTLFLAG_RD,
+SYSCTL_INT(_kern_ipc, OID_AUTO, pipes, CTLFLAG_RD|CTLFLAG_LOCKED,
           &amountpipes, 0, "Current # of pipes");
-SYSCTL_INT(_kern_ipc, OID_AUTO, bigpipes, CTLFLAG_RD,
+SYSCTL_INT(_kern_ipc, OID_AUTO, bigpipes, CTLFLAG_RD|CTLFLAG_LOCKED,
           &nbigpipe, 0, "Current # of big pipes");
-SYSCTL_INT(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD,
+SYSCTL_INT(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD|CTLFLAG_LOCKED,
           &amountpipekva, 0, "Pipe KVA usage");
-SYSCTL_INT(_kern_ipc, OID_AUTO, pipekvawired, CTLFLAG_RD,
+SYSCTL_INT(_kern_ipc, OID_AUTO, pipekvawired, CTLFLAG_RD|CTLFLAG_LOCKED,
           &amountpipekvawired, 0, "Pipe wired KVA usage");
 #endif
 
@@ -1332,6 +1332,16 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused int flags,
                                error = EAGAIN;
                                break;
                        }
+
+                       /*
+                        * If read side wants to go away, we just issue a signal
+                        * to ourselves.
+                        */
+                       if (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) {
+                               error = EPIPE;
+                               break;
+                       }       
+
                        /*
                         * We have no more space and have something to offer,
                         * wake up select/poll.
@@ -1344,14 +1354,6 @@ pipe_write(struct fileproc *fp, struct uio *uio, __unused int flags,
 
                        if (error != 0)
                                break;
-                       /*
-                        * If read side wants to go away, we just issue a signal
-                        * to ourselves.
-                        */
-                       if (wpipe->pipe_state & (PIPE_DRAIN | PIPE_EOF)) {
-                               error = EPIPE;
-                               break;
-                       }       
                }
        }
        --wpipe->pipe_busy;
@@ -1741,8 +1743,14 @@ filt_piperead(struct knote *kn, long hint)
                kn->kn_flags |= EV_EOF;
                retval = 1;
        } else {
-               retval = (kn->kn_sfflags & NOTE_LOWAT) ?
-                        (kn->kn_data >= kn->kn_sdata) : (kn->kn_data > 0);
+               int64_t lowwat = 1;
+               if (kn->kn_sfflags & NOTE_LOWAT) {
+                       if (rpipe->pipe_buffer.size && kn->kn_sdata > rpipe->pipe_buffer.size)
+                               lowwat = rpipe->pipe_buffer.size;
+                       else if (kn->kn_sdata > lowwat)
+                               lowwat = kn->kn_sdata;
+               }
+               retval = kn->kn_data >= lowwat;
        }
 
        if (hint == 0)
@@ -1779,17 +1787,24 @@ filt_pipewrite(struct knote *kn, long hint)
        }
        kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt;
        if (!kn->kn_data && wpipe->pipe_buffer.size == 0)
-               kn->kn_data = 1; /* unwritten pipe is ready for write */
+               kn->kn_data = PIPE_BUF; /* unwritten pipe is ready for write */
 
 #ifndef PIPE_NODIRECT
        if (wpipe->pipe_state & PIPE_DIRECTW)
                kn->kn_data = 0;
 #endif
+       int64_t lowwat = PIPE_BUF;
+       if (kn->kn_sfflags & NOTE_LOWAT) {
+               if (wpipe->pipe_buffer.size && kn->kn_sdata > wpipe->pipe_buffer.size)
+                       lowwat = wpipe->pipe_buffer.size;
+               else if (kn->kn_sdata > lowwat)
+                       lowwat = kn->kn_sdata;
+       }
+       
        if (hint == 0)
                PIPE_UNLOCK(rpipe);
 
-       return (kn->kn_data >= ((kn->kn_sfflags & NOTE_LOWAT) ?
-                                kn->kn_sdata : PIPE_BUF));
+       return (kn->kn_data >= lowwat);
 }
 
 int