OpenSSH solaris: bad return code after exec of remote command
Markus Friedl
markus at openbsd.org
Thu Oct 11 06:22:50 EST 2001
I wrote:
> it's easy to reproduce your problem:
>
> ssh -n localhost 'echo x; exec > /dev/null 2>&1; sleep 3; exit 5;'
could you please try this diff against the current CVS
hope everything else stil works...
-m
Index: channels.c
===================================================================
RCS file: /cvs/openssh_cvs/channels.c,v
retrieving revision 1.110
diff -u -r1.110 channels.c
--- channels.c 2001/10/10 05:14:38 1.110
+++ channels.c 2001/10/10 20:26:54
@@ -331,10 +331,6 @@
debug3("channel_free: status: %s", s);
xfree(s);
- if (c->detach_user != NULL) {
- debug("channel_free: channel %d: detaching channel user", c->self);
- c->detach_user(c->self, NULL);
- }
if (c->sock != -1)
shutdown(c->sock, SHUT_RDWR);
channel_close_fds(c);
@@ -1520,6 +1516,30 @@
channel_handler_init_15();
}
+/* gc dead channels */
+static void
+channel_garbage_collect(Channel *c)
+{
+ if (c == NULL)
+ return;
+ debug("channel %d: gc called", c->self);
+ if (c->detach_user != NULL) {
+ if (!chan_is_dead(c, 0))
+ return;
+ debug("channel %d: gc: notify user", c->self);
+ c->detach_user(c->self, NULL);
+ /* if we still have a callback */
+ if (c->detach_user != NULL)
+ return;
+ debug("channel %d: gc: user removed callback", c->self);
+ }
+ debug("channel %d: gc: after notify user", c->self);
+ if (!chan_is_dead(c, 1))
+ return;
+ debug("channel %d: garbage collecting", c->self);
+ channel_free(c);
+}
+
static void
channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
{
@@ -1537,24 +1557,7 @@
continue;
if (ftab[c->type] != NULL)
(*ftab[c->type])(c, readset, writeset);
- if (chan_is_dead(c)) {
- /*
- * we have to remove the fd's from the select mask
- * before the channels are free'd and the fd's are
- * closed
- */
- if (c->wfd != -1)
- FD_CLR(c->wfd, writeset);
- if (c->rfd != -1)
- FD_CLR(c->rfd, readset);
- if (c->efd != -1) {
- if (c->extended_usage == CHAN_EXTENDED_READ)
- FD_CLR(c->efd, readset);
- if (c->extended_usage == CHAN_EXTENDED_WRITE)
- FD_CLR(c->efd, writeset);
- }
- channel_free(c);
- }
+ channel_garbage_collect(c);
}
}
@@ -1625,7 +1628,7 @@
if (compat20 &&
(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
/* XXX is this true? */
- debug2("channel %d: no data after CLOSE", c->self);
+ debug3("channel %d: will not send data after CLOSE", c->self);
continue;
}
Index: channels.h
===================================================================
RCS file: /cvs/openssh_cvs/channels.h,v
retrieving revision 1.41
diff -u -r1.41 channels.h
--- channels.h 2001/10/10 05:14:39 1.41
+++ channels.h 2001/10/10 20:26:54
@@ -214,7 +214,7 @@
/* channel close */
-int chan_is_dead(Channel *);
+int chan_is_dead(Channel *, int);
void chan_mark_dead(Channel *);
void chan_init_iostates(Channel *);
void chan_init(void);
Index: clientloop.c
===================================================================
RCS file: /cvs/openssh_cvs/clientloop.c,v
retrieving revision 1.65
diff -u -r1.65 clientloop.c
--- clientloop.c 2001/09/18 05:51:14 1.65
+++ clientloop.c 2001/10/10 20:26:57
@@ -753,6 +753,7 @@
if (id != session_ident)
error("client_channel_closed: id %d != session_ident %d",
id, session_ident);
+ channel_cancel_cleanup(id);
session_closed = 1;
if (in_raw_mode())
leave_raw_mode();
Index: nchan.c
===================================================================
RCS file: /cvs/openssh_cvs/nchan.c,v
retrieving revision 1.28
diff -u -r1.28 nchan.c
--- nchan.c 2001/09/20 19:33:33 1.28
+++ nchan.c 2001/10/10 20:26:58
@@ -432,7 +432,7 @@
}
int
-chan_is_dead(Channel *c)
+chan_is_dead(Channel *c, int send)
{
if (c->type == SSH_CHANNEL_ZOMBIE) {
debug("channel %d: zombie", c->self);
@@ -461,7 +461,14 @@
"read": "write");
} else {
if (!(c->flags & CHAN_CLOSE_SENT)) {
- chan_send_close2(c);
+ if (send) {
+ chan_send_close2(c);
+ } else {
+ if (c->flags & CHAN_CLOSE_RCVD) {
+ debug("channel %d: XXX almost dead", c->self);
+ return 1;
+ }
+ }
}
if ((c->flags & CHAN_CLOSE_SENT) &&
(c->flags & CHAN_CLOSE_RCVD)) {
Index: serverloop.c
===================================================================
RCS file: /cvs/openssh_cvs/serverloop.c,v
retrieving revision 1.80
diff -u -r1.80 serverloop.c
--- serverloop.c 2001/10/10 05:14:39 1.80
+++ serverloop.c 2001/10/10 20:26:59
@@ -208,9 +208,6 @@
max_time_milliseconds = options.client_alive_interval * 1000;
}
- /* When select fails we restart from here. */
-retry_select:
-
/* Allocate and update select() masks for channel descriptors. */
channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 0);
@@ -275,10 +272,11 @@
ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp);
if (ret == -1) {
+ memset(*readsetp, 0, *maxfdp);
+ memset(*writesetp, 0, *maxfdp);
if (errno != EINTR)
error("select: %.100s", strerror(errno));
- else
- goto retry_select;
+ debug("XXX select: %.100s", strerror(errno));
}
if (ret == 0 && client_alive_scheduled)
client_alive_check();
@@ -668,13 +666,30 @@
/* NOTREACHED */
}
+static void
+collect_children(void)
+{
+ pid_t pid;
+ sigset_t oset, nset;
+ int status;
+
+ /* block SIGCHLD while we check for dead children */
+ sigemptyset(&nset);
+ sigaddset(&nset, SIGCHLD);
+ sigprocmask(SIG_BLOCK, &nset, &oset);
+ if (child_terminated) {
+ while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
+ session_close_by_pid(pid, status);
+ child_terminated = 0;
+ }
+ sigprocmask(SIG_SETMASK, &oset, NULL);
+}
+
void
server_loop2(Authctxt *authctxt)
{
fd_set *readset = NULL, *writeset = NULL;
- int rekeying = 0, max_fd, status, nalloc = 0;
- pid_t pid;
- sigset_t oset, nset;
+ int rekeying = 0, max_fd, nalloc = 0;
debug("Entering interactive session for SSH2.");
@@ -698,16 +713,7 @@
wait_until_can_do_something(&readset, &writeset, &max_fd,
&nalloc, 0);
- /* block SIGCHLD while we check for dead children */
- sigemptyset(&nset);
- sigaddset(&nset, SIGCHLD);
- sigprocmask(SIG_BLOCK, &nset, &oset);
- if (child_terminated) {
- while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
- session_close_by_pid(pid, status);
- child_terminated = 0;
- }
- sigprocmask(SIG_SETMASK, &oset, NULL);
+ collect_children();
if (!rekeying)
channel_after_select(readset, writeset);
process_input(readset);
@@ -715,6 +721,8 @@
break;
process_output(writeset);
}
+ collect_children();
+
if (readset)
xfree(readset);
if (writeset)
@@ -722,11 +730,6 @@
/* free all channels, no more reads and writes */
channel_free_all();
-
- /* collect remaining dead children, XXX not necessary? */
- mysignal(SIGCHLD, SIG_DFL);
- while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
- session_close_by_pid(pid, status);
/* close remaining sessions, e.g remove wtmp entries */
session_close_all();
Index: session.c
===================================================================
RCS file: /cvs/openssh_cvs/session.c,v
retrieving revision 1.152
diff -u -r1.152 session.c
--- session.c 2001/10/10 05:14:39 1.152
+++ session.c 2001/10/10 20:27:03
@@ -1961,18 +1961,15 @@
debug("session_close_by_channel: no session for channel %d", id);
return;
}
- /* disconnect channel */
- channel_cancel_cleanup(s->chanid);
- s->chanid = -1;
-
- debug("session_close_by_channel: channel %d kill %d", id, s->pid);
+ debug("session_close_by_channel: channel %d child %d", id, s->pid);
if (s->pid != 0) {
- /* notify child */
- if (kill(s->pid, SIGHUP) < 0)
- error("session_close_by_channel: kill %d: %s",
- s->pid, strerror(errno));
+ debug("session_close_by_channel: channel %d: has child", id);
+ return;
}
+ channel_cancel_cleanup(s->chanid);
+ s->chanid = -1;
session_close(s);
+ return;
}
void
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