Module Name: src
Committed By: christos
Date: Tue Jun 5 19:33:18 UTC 2012
Modified Files:
src/usr.sbin/syslogd: syslogd.c
Log Message:
Open and write to ttys using non-blocking I/O to prevent DoS when hardware
or software flow control prevents tty writes or when the tty line is too
slow to respond.
To generate a diff of this commit:
cvs rdiff -u -r1.107 -r1.108 src/usr.sbin/syslogd/syslogd.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.sbin/syslogd/syslogd.c
diff -u src/usr.sbin/syslogd/syslogd.c:1.107 src/usr.sbin/syslogd/syslogd.c:1.108
--- src/usr.sbin/syslogd/syslogd.c:1.107 Mon May 14 21:22:50 2012
+++ src/usr.sbin/syslogd/syslogd.c Tue Jun 5 15:33:17 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: syslogd.c,v 1.107 2012/05/15 01:22:50 christos Exp $ */
+/* $NetBSD: syslogd.c,v 1.108 2012/06/05 19:33:17 christos Exp $ */
/*
* Copyright (c) 1983, 1988, 1993, 1994
@@ -39,7 +39,7 @@ __COPYRIGHT("@(#) Copyright (c) 1983, 19
#if 0
static char sccsid[] = "@(#)syslogd.c 8.3 (Berkeley) 4/4/94";
#else
-__RCSID("$NetBSD: syslogd.c,v 1.107 2012/05/15 01:22:50 christos Exp $");
+__RCSID("$NetBSD: syslogd.c,v 1.108 2012/06/05 19:33:17 christos Exp $");
#endif
#endif /* not lint */
@@ -70,6 +70,7 @@ __RCSID("$NetBSD: syslogd.c,v 1.107 2012
* TLS, syslog-protocol, and syslog-sign code by Martin Schuette.
*/
#define SYSLOG_NAMES
+#include <poll.h>
#include "syslogd.h"
#include "extern.h"
@@ -266,6 +267,7 @@ void free_cred_SLIST(struct peer_cred_h
static inline void
free_incoming_tls_sockets(void);
#endif /* !DISABLE_TLS */
+static int writev1(int, struct iovec *, size_t);
/* for make_timestamp() */
#define TIMESTAMPBUFSIZE 35
@@ -1835,7 +1837,7 @@ logmsg(struct buf_msg *buffer)
/* log the message to the particular outputs */
if (!Initialized) {
f = &consfile;
- f->f_file = open(ctty, O_WRONLY, 0);
+ f->f_file = open(ctty, O_WRONLY | O_NDELAY, 0);
if (f->f_file >= 0) {
DELREF(f->f_prevmsg);
@@ -2404,7 +2406,8 @@ fprintlog(struct filed *f, struct buf_ms
DPRINTF(D_MISC, "Logging to %s %s\n",
TypeInfo[f->f_type].name, f->f_un.f_fname);
again:
- if (writev(f->f_file, iov, v - iov) < 0) {
+ if ((f->f_type == F_FILE ? writev(f->f_file, iov, v - iov) :
+ writev1(f->f_file, iov, v - iov)) < 0) {
e = errno;
if (f->f_type == F_FILE && e == ENOSPC) {
int lasterror = f->f_lasterror;
@@ -2419,7 +2422,7 @@ fprintlog(struct filed *f, struct buf_ms
*/
if ((e == EIO || e == EBADF) && f->f_type != F_FILE) {
f->f_file = open(f->f_un.f_fname,
- O_WRONLY|O_APPEND, 0);
+ O_WRONLY|O_APPEND|O_NDELAY, 0);
if (f->f_file < 0) {
f->f_type = F_UNUSED;
logerror("%s", f->f_un.f_fname);
@@ -3605,7 +3608,7 @@ cfline(size_t linenum, const char *line,
const char *host)
{
struct addrinfo hints, *res;
- int error, i, pri, syncfile;
+ int error, i, pri, syncfile, flags;
const char *p, *q;
char *bp;
char buf[MAXLINE];
@@ -3819,19 +3822,22 @@ cfline(size_t linenum, const char *line,
f->f_flags |= FFLAG_SIGN;
#endif /* !DISABLE_SIGN */
(void)strlcpy(f->f_un.f_fname, p, sizeof(f->f_un.f_fname));
- if ((f->f_file = open(p, O_WRONLY|O_APPEND, 0)) < 0) {
+ if (isatty(f->f_file)) {
+ f->f_type = F_TTY;
+ if (strcmp(p, ctty) == 0)
+ f->f_type = F_CONSOLE;
+ flags = O_NDELAY;
+ } else {
+ f->f_type = F_FILE;
+ flags = 0;
+ }
+ if ((f->f_file = open(p, O_WRONLY|O_APPEND|flags, 0)) < 0) {
f->f_type = F_UNUSED;
logerror("%s", p);
break;
}
if (syncfile)
f->f_flags |= FFLAG_SYNC;
- if (isatty(f->f_file))
- f->f_type = F_TTY;
- else
- f->f_type = F_FILE;
- if (strcmp(p, ctty) == 0)
- f->f_type = F_CONSOLE;
break;
case '|':
@@ -4695,3 +4701,42 @@ copy_config_value_word(char **mem, const
*p = ++q;
return true;
}
+
+static int
+writev1(int fd, struct iovec *iov, size_t count)
+{
+ ssize_t nw = 0, tot = 0;
+ size_t ntries = 5;
+
+ while (ntries--) {
+ switch ((nw = writev(fd, iov, count))) {
+ case -1:
+ if (errno == EAGAIN || errno == EWOULDBLOCK) {
+ struct pollfd pfd;
+ pfd.fd = fd;
+ pfd.events = POLLOUT;
+ pfd.revents = 0;
+ (void)poll(&pfd, 1, 500);
+ continue;
+ } else
+ return -1;
+ case 0:
+ return 0;
+ default:
+ tot += nw;
+ while (nw > 0) {
+ if (iov->iov_len > nw) {
+ iov->iov_len -= nw;
+ iov->iov_base += nw;
+ break;
+ } else {
+ if (count-- == 0)
+ return tot;
+ nw -= iov->iov_len;
+ iov++;
+ }
+ }
+ }
+ }
+ return tot == 0 ? nw : tot;
+}
