similar to: Why dup()?

I've been using ssh without it duping stdout and stderr, and had no problems.? I think this change should be made to the master source. WHAT IS THE PROBLEM WITH SSH RIGHT NOW? It duplicates FILENO_STDOUT and FILENO_STDERR, thus there are two descriptors for each of these files.? When the remote program closes its stdout or stderr, the remote sshd sends the appropriate message to the local

Hello, I'm running a sshd server using the -e flag so that I can capture its whole output and later send it to the user. I'm also setting LogLevel to DEBUG1 in the configuration file and I don't want to disturb syslogd. But the problem is that it doesn't work as expected (or as I expect, which I think should be the correct behavior). The log file ends up being empty because the

At least it appears that way on my FreeBSD 8.1 system. This is probably unnoticeable in regular use but I happen to use CFengine(v2) for system configuration & monitoring. If it notices dovecot not running it tries to start it and hangs. I believe cfengine (cfagent) has created a pipe to monitor the start commmand's stderr and is waiting for this pipe to close. This never happens

https://www.redhat.com/archives/libguestfs/2019-August/thread.html#00347 Thanks: Eric Blake and Daniel P. Berrangé --- common/utils/utils.h | 1 + server/connections.c | 4 ++-- server/crypto.c | 5 +++-- server/main.c | 23 +++++++++++++++++++++++ common/utils/utils.c | 29 +++++++++++++++++++++++++++++ 5 files changed, 58 insertions(+), 4 deletions(-) diff --git

- add a flag to request chroot for the process, which is done only as very last (before chdir) operation before exec'ing the process in the child: this avoids using CHROOT_IN & CHROOT_OUT around command* invocations, and reduces the code spent in chroot mode - add failure checks for dup2 and open done in child, not proceeding to executing the process if they fail - open /dev/null

Please review the function below, forkoff(), meant to be used in clientloop.c instead of daemon() and the code in process_escapes(). The intention is to make ~D ( like ~& but also detach) possible and to make it possible for ssh -f (or ssh -f -f - see other thread on this) to detach, not just forkoff(). I also intend to use the same detach technique in a feature patch for the hang-on-exit

Hi, I fell on this using openssh on cygwin. Though it may be a cygwin related issue, I think it's may be a bug on the main openssh tree. Thus my posting here. I'm CC'ing to the public list for information. The part of code I'm refering to is : /* XXX might close listen socket */ (void)dup2(fd, STDIN_FILENO); (void)dup2(fd, STDOUT_FILENO);

Background ========== "ssh -f ..." causes ssh to fork into the background when userauth successfully completes. WHAT === With this patch "ssh -f -f ..." causes ssh to fork into the background when the first forwarded port/x11 display/agent is successfully opened. WHY === This feature makes launching remote X11 apps more reliable: when ssh exits it must have exited because

This allows me to set 'ControlPath ~/.ssh/sockets/%h.%p.%u' for example. Have I missed a good reason why ssh_connect finds the default port number for itself instead of just having it in options.port (like we do for the the default in options.user)? --- openssh-4.1p1/ssh.c~ 2005-06-12 09:47:18.000000000 +0100 +++ openssh-4.1p1/ssh.c 2005-06-12 09:40:53.000000000 +0100 @@ -604,6 +604,17

> Case in point; EAGAIN can come if you give your fd to another process > and continue using it yourself. > Short counts; It is documented behavior that read() and write() may > return short counts. It is not documented why, so you can not make > any assumptions. You might be right about short counts but if you're right about EAGAIN, there are bugs everywhere. My first

Improve readability of commandrvf() by replacing bare int values for file descriptors with their symbolic names STD{IN,OUT,ERR}_FILENO. Also add PIPE_READ and PIPE_WRITE for referencing relevant ends of a pipe. --- daemon/guestfsd.c | 79 +++++++++++++++++++++++++++++-------------------------- 1 file changed, 42 insertions(+), 37 deletions(-) diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c

On 13/10/17 16:22, Damien Miller wrote: > At a minimum, I think we'd have to dup2 a fd to /dev/null to > STDOUT_FILENO so writes to stdout (e.g. from ill-behaved > libraries) have somewhere to go. Would that really be useful?? Output from Ill-behaved libraries, written fd 1, already go to the same place.? Don't forget, dup does not create a new file, it creates a duplicate

This is what I've been playing with in response to my earlier question about what to do with 'nbdkit -s sh -' (https://www.redhat.com/archives/libguestfs/2020-April/msg00032.html) I'm still open to ideas on a better name, and/or whether adding <stdbool.h> to our public include files is a good idea (if not, returning int instead of bool is tolerable). Eric Blake (2):

As shown in the previous patch, plugins may choose to use stdin or stdout during .config. But from .get_ready onwards, well-written plugins shouldn't be needing any further use of stdin/out. We already swapped stdin/out to /dev/null while daemonizing, but did not do do during -f or --run, which leads to some surprising inconsistency when trying to debug a plugin that works in the foreground

On 12/10/17 12:54, Clark Wang wrote: > How did you hit the problem? "ssh host echo hello | cat" works fine > for me. That's because ssh exited, not because of EOF. Consider the following: ?? ssh localhost 'exec cat > /dev/null' | { read l; echo ${l:-EOF}; } One should see "EOF" immediately (for values of immediate that include startup latency), but

V3 was here: <http://mid.mail-archive.com/20230215141158.2426855-1-lersek at redhat.com>. See the Notes section on each patch for the v4 updates. The series is nearly ready for merging: every patch has at least one R-b tag, except "socket activation: avoid manipulating the sign bit". The series builds, and passes "make check" and "make check-valgrind", at

In v2: - use int instead of bool in the public header - split the tests from the code - don't overload test-layers; instead, add new tests - add a missing fflush exposed by the new tests - other minor cleanups Eric Blake (3): server: Add nbdkit_stdio_safe server: Sanitize stdin/out before running plugin code server: More tests of stdin/out handling docs/nbdkit-plugin.pod |

On Wed, Dec 02, 2015 at 02:00:57PM +0100, Pino Toscano wrote: > - add a flag to request chroot for the process, which is done only as > very last (before chdir) operation before exec'ing the process in the > child: this avoids using CHROOT_IN & CHROOT_OUT around command* > invocations, and reduces the code spent in chroot mode > - add failure checks for dup2 and open

As shown in the previous patch, plugins may choose to use stdin or stdout during .config. But from .get_ready onwards, well-written plugins shouldn't be needing any further use of stdin/out. We already swapped stdin/out to /dev/null while daemonizing, but did not do do during -f or --run, which leads to some surprising inconsistency when trying to debug a plugin that works in the foreground

On Mon, Apr 13, 2020 at 07:28:59PM -0500, Eric Blake wrote: [...] This patch is fine and can be pushed if you want, but I've got some small comments. > +If C<nbdkit_stdio_safe> returns true, the value of the configuration > +parameter may be used to trigger reading additional data through stdin > +(such as a password or inline script). I wonder if we want to say "returns