Attachment 1507 Details for Bug 1470 – adjust Linux out-of-memory killer

[patch] adjust Linux out-of-memory killer

oom-adjust.diff (text/plain), 4.81 KB, created by Colin Watson on 2008-05-26 08:31:50 AEST

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Creator: Colin Watson

Created: 2008-05-26 08:31:50 AEST

Size: 4.81 KB

patch

obsolete

>? .scp.c.swp
>Index: configure.ac
>===================================================================
>RCS file: /cvs/openssh/configure.ac,v
>retrieving revision 1.399
>diff -p -u -r1.399 configure.ac
>--- configure.ac	19 May 2008 22:57:06 -0000	1.399
>+++ configure.ac	25 May 2008 22:07:34 -0000
>@@ -579,6 +579,7 @@ main() { if (NSVersionOfRunTimeLibrary("
> 		AC_DEFINE(SSH_TUN_PREPEND_AF, 1,
> 		    [Prepend the address family to IP tunnel traffic])
> 	fi
>+	AC_DEFINE(OOM_ADJUST, 1, [Adjust Linux out-of-memory killer])
> 	;;
> mips-sony-bsd|mips-sony-newsos4)
> 	AC_DEFINE(NEED_SETPGRP, 1, [Need setpgrp to acquire controlling tty])
>Index: sshd.c
>===================================================================
>RCS file: /cvs/openssh/sshd.c,v
>retrieving revision 1.374
>diff -p -u -r1.374 sshd.c
>--- sshd.c	19 May 2008 05:05:08 -0000	1.374
>+++ sshd.c	25 May 2008 22:07:34 -0000
>@@ -250,6 +250,11 @@ Buffer loginmsg;
> /* Unprivileged user */
> struct passwd *privsep_pw = NULL;
> 
>+#ifdef OOM_ADJUST
>+/* Linux out-of-memory killer adjustment */
>+static char oom_adj_save[8];
>+#endif
>+
> /* Prototypes for various functions defined later in this file. */
> void destroy_sensitive_data(void);
> void demote_sensitive_data(void);
>@@ -901,6 +906,31 @@ recv_rexec_state(int fd, Buffer *conf)
> 	debug3("%s: done", __func__);
> }
> 
>+#ifdef OOM_ADJUST
>+/*
>+ * If requested in the environment, tell the Linux kernel's out-of-memory
>+ * killer to avoid sshd. The old state will be restored when forking child
>+ * processes.
>+ */
>+static void
>+oom_adjust_startup(void)
>+{
>+	const char *oom_adj = getenv("SSHD_OOM_ADJUST");
>+
>+	if (!oom_adj)
>+		return;
>+	oom_adj_get(oom_adj_save, sizeof(oom_adj_save));
>+	oom_adj_set(oom_adj);
>+}
>+
>+static void
>+oom_restore(void)
>+{
>+	if (oom_adj_save[0])
>+		oom_adj_set(oom_adj_save);
>+}
>+#endif
>+
> /* Accept a connection from inetd */
> static void
> server_accept_inetd(int *sock_in, int *sock_out)
>@@ -1606,6 +1636,11 @@ main(int ac, char **av)
> 	/* ignore SIGPIPE */
> 	signal(SIGPIPE, SIG_IGN);
> 
>+#ifdef OOM_ADJUST
>+	/* Adjust out-of-memory killer */
>+	oom_adjust_startup();
>+#endif
>+
> 	/* Get a connection, either from inetd or a listening TCP socket */
> 	if (inetd_flag) {
> 		server_accept_inetd(&sock_in, &sock_out);
>@@ -1643,6 +1678,10 @@ main(int ac, char **av)
> 
> 	/* This is the child processing a new connection. */
> 	setproctitle("%s", "[accepted]");
>+
>+#ifdef OOM_ADJUST
>+	oom_restore();
>+#endif
> 
> 	/*
> 	 * Create a new session and process group since the 4.4BSD
>Index: openbsd-compat/port-linux.c
>===================================================================
>RCS file: /cvs/openssh/openbsd-compat/port-linux.c,v
>retrieving revision 1.5
>diff -p -u -r1.5 port-linux.c
>--- openbsd-compat/port-linux.c	26 Mar 2008 20:27:21 -0000	1.5
>+++ openbsd-compat/port-linux.c	25 May 2008 22:07:34 -0000
>@@ -18,7 +18,7 @@
>  */
> 
> /*
>- * Linux-specific portability code - just SELinux support at present
>+ * Linux-specific portability code
>  */
> 
> #include "includes.h"
>@@ -27,8 +27,16 @@
> #include <stdarg.h>
> #include <string.h>
> 
>-#ifdef WITH_SELINUX
>+#ifdef OOM_ADJUST
>+#include <sys/types.h>
>+#include <sys/stat.h>
>+#include <fcntl.h>
>+#include <unistd.h>
>+#endif
>+
> #include "log.h"
>+
>+#ifdef WITH_SELINUX
> #include "port-linux.h"
> 
> #include <selinux/selinux.h>
>@@ -169,3 +177,47 @@ ssh_selinux_setup_pty(char *pwname, cons
> 	debug3("%s: done", __func__);
> }
> #endif /* WITH_SELINUX */
>+
>+#ifdef OOM_ADJUST
>+/* Get the out-of-memory adjustment file for the current process */
>+int
>+oom_adj_open(void)
>+{
>+	int fd = open("/proc/self/oom_adj", O_RDWR);
>+	if (fd < 0)
>+		logit("error opening /proc/self/oom_adj: %s", strerror(errno));
>+	return fd;
>+}
>+
>+/* Get the current OOM adjustment */
>+int
>+oom_adj_get(char *buf, size_t maxlen)
>+{
>+	ssize_t n;
>+	int fd = oom_adj_open();
>+	if (fd < 0)
>+		return -1;
>+	n = read(fd, buf, maxlen);
>+	if (n < 0)
>+		logit("error reading /proc/self/oom_adj: %s", strerror(errno));
>+	else
>+		buf[n] = '\0';
>+	close(fd);
>+	return n < 0 ? -1 : 0;
>+}
>+
>+/* Set the current OOM adjustment */
>+int
>+oom_adj_set(const char *buf)
>+{
>+	ssize_t n;
>+	int fd = oom_adj_open();
>+	if (fd < 0)
>+		return -1;
>+	n = write(fd, buf, strlen(buf));
>+	if (n < 0)
>+		logit("error writing /proc/self/oom_adj: %s", strerror(errno));
>+	close(fd);
>+	return n < 0 ? -1 : 0;
>+}
>+#endif
>Index: openbsd-compat/port-linux.h
>===================================================================
>RCS file: /cvs/openssh/openbsd-compat/port-linux.h,v
>retrieving revision 1.2
>diff -p -u -r1.2 port-linux.h
>--- openbsd-compat/port-linux.h	26 Mar 2008 20:27:21 -0000	1.2
>+++ openbsd-compat/port-linux.h	25 May 2008 22:07:34 -0000
>@@ -25,4 +25,10 @@ void ssh_selinux_setup_pty(char *, const
> void ssh_selinux_setup_exec_context(char *);
> #endif
> 
>+#ifdef OOM_ADJUST
>+int oom_adj_open(void);
>+int oom_adj_get(char *buf, size_t maxlen);
>+int oom_adj_set(const char *buf);
>+#endif
>+
> #endif /* ! _PORT_LINUX_H */

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Attachments on bug 1470: 1507 | 1712 | 1740 | 1741 | 1742