Backport upstream patch to install a SIGCHLD handler to reap expired ssh

child processes, preventing lots of zombies when using ControlPersist
(closes: #594687).

4 files changed, 83 insertions, 0 deletions

diff --git a/debian/changelog b/debian/changelog
index e41eee767..0cdc326ae 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+openssh (1:5.6p1-2) UNRELEASED; urgency=low
+
+  * Backport upstream patch to install a SIGCHLD handler to reap expired ssh
+    child processes, preventing lots of zombies when using ControlPersist
+    (closes: #594687).
+
+ -- Colin Watson <cjwatson@debian.org>  Tue, 26 Oct 2010 12:58:39 +0100
+
 openssh (1:5.6p1-1) experimental; urgency=low
 
   * New upstream release (http://www.openssh.com/txt/release-5.6):
diff --git a/debian/patches/series b/debian/patches/series
index fe14d7a8d..f3c6a87e0 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -41,3 +41,4 @@ doc-hash-tab-completion.patch
 # Debian-specific configuration
 gnome-ssh-askpass2-icon.patch
 debian-config.patch
+ssh-sigchld.patch
diff --git a/debian/patches/ssh-sigchld.patch b/debian/patches/ssh-sigchld.patch
new file mode 100644
index 000000000..21d286b21
--- /dev/null
+++ b/debian/patches/ssh-sigchld.patch
@@ -0,0 +1,55 @@
+Description: Install a SIGCHLD handler to reap expired child processes
+Origin: upstream, http://bazaar.launchpad.net/~vcs-imports/openssh/main/revision/6166
+Bug-Debian: http://bugs.debian.org/594687
+Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1812
+Forwarded: not-needed
+Last-Update: 2010-10-26
+
+Index: b/ssh.c
+===================================================================
+--- a/ssh.c
++++ b/ssh.c
+@@ -50,6 +50,7 @@
+ #include <sys/ioctl.h>
+ #include <sys/param.h>
+ #include <sys/socket.h>
++#include <sys/wait.h>
+ 
+ #include <ctype.h>
+ #include <errno.h>
+@@ -210,6 +211,7 @@
+ static int ssh_session(void);
+ static int ssh_session2(void);
+ static void load_public_identity_files(void);
++static void main_sigchld_handler(int);
+ 
+ /* from muxclient.c */
+ void muxclient(const char *);
+@@ -849,6 +851,7 @@
+            tilde_expand_filename(options.user_hostfile2, original_real_uid);
+ 
+        signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
++       signal(SIGCHLD, main_sigchld_handler);
+ 
+        /* Log into the remote system.  Never returns if the login fails. */
+        ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
+@@ -1532,3 +1535,19 @@
+        bzero(pwdir, strlen(pwdir));
+        xfree(pwdir);
+ }
++
++static void
++main_sigchld_handler(int sig)
++{
++       int save_errno = errno;
++       pid_t pid;
++       int status;
++
++       while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
++           (pid < 0 && errno == EINTR))
++               ;
++
++       signal(sig, main_sigchld_handler);
++       errno = save_errno;
++}
++
diff --git a/ssh.c b/ssh.c
index ab3c33d87..22d4f53c4 100644
--- a/ssh.c
+++ b/ssh.c
@@ -50,6 +50,7 @@
 #include <sys/ioctl.h>
 #include <sys/param.h>
 #include <sys/socket.h>
+#include <sys/wait.h>
 
 #include <ctype.h>
 #include <errno.h>
@@ -210,6 +211,7 @@ usage(void)
 static int ssh_session(void);
 static int ssh_session2(void);
 static void load_public_identity_files(void);
+static void main_sigchld_handler(int);
 
 /* from muxclient.c */
 void muxclient(const char *);
@@ -849,6 +851,7 @@ main(int ac, char **av)
             tilde_expand_filename(options.user_hostfile2, original_real_uid);
 
         signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
+        signal(SIGCHLD, main_sigchld_handler);
 
         /* Log into the remote system.  Never returns if the login fails. */
         ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr,
@@ -1532,3 +1535,19 @@ load_public_identity_files(void)
         bzero(pwdir, strlen(pwdir));
         xfree(pwdir);
 }
+
+static void
+main_sigchld_handler(int sig)
+{
+        int save_errno = errno;
+        pid_t pid;
+        int status;
+
+        while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
+            (pid < 0 && errno == EINTR))
+                ;
+
+        signal(sig, main_sigchld_handler);
+        errno = save_errno;
+}
+