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Check for signals while reading /dev/urandom. Reading 10MB from

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/dev/urandom takes about 38 seconds on a P5/133.  It is useful
to be able to kill such reads almost immediately.  Processes
doing such reads are now scheduled so their denial of service
is no worse than that of processes looping in user mode.
This commit is contained in:
Bruce Evans 1999-02-02 14:14:05 +00:00
parent 8b6ca0359b
commit bb25f0dd23
2 changed files with 24 additions and 2 deletions
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13
sys/amd64/amd64/mem.c
View File

@ -38,7 +38,7 @@
*
* from: Utah $Hdr: mem.c 1.13 89/10/08$
* from: @(#)mem.c 7.2 (Berkeley) 5/9/91
* $Id: mem.c,v 1.52 1998/06/21 11:33:29 bde Exp $
* $Id: mem.c,v 1.53 1998/11/08 12:39:01 dfr Exp $
*/
/*
@ -59,6 +59,7 @@
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <machine/frame.h>
#include <machine/random.h>
@ -287,6 +288,16 @@ mmrw(dev, uio, flags)
c = iov->iov_len;
break;
}
if (CURSIG(curproc) != 0) {
/*
* Use tsleep() to get the error code right.
* It should return immediately.
*/
error = tsleep(&random_softc[0],
PZERO | PCATCH, "urand", 1);
if (error != 0 && error != EWOULDBLOCK)
continue;
}
if (buf == NULL)
buf = (caddr_t)
malloc(PAGE_SIZE, M_TEMP, M_WAITOK);

13
sys/i386/i386/mem.c
View File

@ -38,7 +38,7 @@
*
* from: Utah $Hdr: mem.c 1.13 89/10/08$
* from: @(#)mem.c 7.2 (Berkeley) 5/9/91
* $Id: mem.c,v 1.52 1998/06/21 11:33:29 bde Exp $
* $Id: mem.c,v 1.53 1998/11/08 12:39:01 dfr Exp $
*/
/*
@ -59,6 +59,7 @@
#include <sys/uio.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/signalvar.h>
#include <machine/frame.h>
#include <machine/random.h>
@ -287,6 +288,16 @@ mmrw(dev, uio, flags)
c = iov->iov_len;
break;
}
if (CURSIG(curproc) != 0) {
/*
* Use tsleep() to get the error code right.
* It should return immediately.
*/
error = tsleep(&random_softc[0],
PZERO | PCATCH, "urand", 1);
if (error != 0 && error != EWOULDBLOCK)
continue;
}
if (buf == NULL)
buf = (caddr_t)
malloc(PAGE_SIZE, M_TEMP, M_WAITOK);