Close file descriptors on re-exec

Use code copied from GLib to close all file descriptors before we reexec ourselves
on the restart Alt-F2 command. This fixes serious memory leaks when we have mapped
graphics buffers.

http://bugzilla.gnome.org/show_bug.cgi?id=579776
This commit is contained in:
Owen W. Taylor 2009-04-21 17:21:06 -04:00
parent 7c8cb8450c
commit 56644dfada
2 changed files with 104 additions and 2 deletions

View File

@ -60,6 +60,9 @@ GJS_JS_NATIVE_DIR=`$PKG_CONFIG --variable=jsnativedir gjs-1.0`
AC_SUBST(GJS_JS_DIR) AC_SUBST(GJS_JS_DIR)
AC_SUBST(GJS_JS_NATIVE_DIR) AC_SUBST(GJS_JS_NATIVE_DIR)
AC_CHECK_FUNCS(fdwalk)
AC_CHECK_HEADERS([sys/resource.h])
# Sets GLIB_GENMARSHAL and GLIB_MKENUMS # Sets GLIB_GENMARSHAL and GLIB_MKENUMS
AM_PATH_GLIB_2_0() AM_PATH_GLIB_2_0()
G_IR_SCANNER=`$PKG_CONFIG --variable=g_ir_scanner gobject-introspection-1.0` G_IR_SCANNER=`$PKG_CONFIG --variable=g_ir_scanner gobject-introspection-1.0`

View File

@ -7,10 +7,12 @@
#include <clutter/glx/clutter-glx.h> #include <clutter/glx/clutter-glx.h>
#include <clutter/x11/clutter-x11.h> #include <clutter/x11/clutter-x11.h>
#include <gdk/gdkx.h> #include <gdk/gdkx.h>
#include <unistd.h> #include <dirent.h>
#include <errno.h> #include <errno.h>
#include <fcntl.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
#include <unistd.h>
#include <dbus/dbus-glib.h> #include <dbus/dbus-glib.h>
#include <libgnomeui/gnome-thumbnail.h> #include <libgnomeui/gnome-thumbnail.h>
@ -592,6 +594,95 @@ shell_global_ungrab_keyboard (ShellGlobal *global)
global->keyboard_grabbed = FALSE; global->keyboard_grabbed = FALSE;
} }
/* Code to close all file descriptors before we exec; copied from gspawn.c in GLib.
*
* Authors: Padraig O'Briain, Matthias Clasen, Lennart Poettering
*
* http://bugzilla.gnome.org/show_bug.cgi?id=469231
* http://bugzilla.gnome.org/show_bug.cgi?id=357585
*/
static int
set_cloexec (void *data, gint fd)
{
if (fd >= GPOINTER_TO_INT (data))
fcntl (fd, F_SETFD, FD_CLOEXEC);
return 0;
}
#ifndef HAVE_FDWALK
static int
fdwalk (int (*cb)(void *data, int fd), void *data)
{
gint open_max;
gint fd;
gint res = 0;
#ifdef HAVE_SYS_RESOURCE_H
struct rlimit rl;
#endif
#ifdef __linux__
DIR *d;
if ((d = opendir("/proc/self/fd"))) {
struct dirent *de;
while ((de = readdir(d))) {
glong l;
gchar *e = NULL;
if (de->d_name[0] == '.')
continue;
errno = 0;
l = strtol(de->d_name, &e, 10);
if (errno != 0 || !e || *e)
continue;
fd = (gint) l;
if ((glong) fd != l)
continue;
if (fd == dirfd(d))
continue;
if ((res = cb (data, fd)) != 0)
break;
}
closedir(d);
return res;
}
/* If /proc is not mounted or not accessible we fall back to the old
* rlimit trick */
#endif
#ifdef HAVE_SYS_RESOURCE_H
if (getrlimit(RLIMIT_NOFILE, &rl) == 0 && rl.rlim_max != RLIM_INFINITY)
open_max = rl.rlim_max;
else
#endif
open_max = sysconf (_SC_OPEN_MAX);
for (fd = 0; fd < open_max; fd++)
if ((res = cb (data, fd)) != 0)
break;
return res;
}
#endif
static void
pre_exec_close_fds(void)
{
fdwalk (set_cloexec, GINT_TO_POINTER(3));
}
/** /**
* shell_global_reexec_self: * shell_global_reexec_self:
* @global: A #ShellGlobal * @global: A #ShellGlobal
@ -622,6 +713,14 @@ shell_global_reexec_self (ShellGlobal *global)
g_ptr_array_add (arr, buf_p); g_ptr_array_add (arr, buf_p);
g_ptr_array_add (arr, NULL); g_ptr_array_add (arr, NULL);
/* Close all file descriptors other than stdin/stdout/stderr, otherwise
* they will leak and stay open after the exec. In particular, this is
* important for file descriptors that represent mapped graphics buffer
* objects.
*/
pre_exec_close_fds ();
execvp (arr->pdata[0], (char**)arr->pdata); execvp (arr->pdata[0], (char**)arr->pdata);
g_warning ("failed to reexec: %s", g_strerror (errno)); g_warning ("failed to reexec: %s", g_strerror (errno));
g_ptr_array_free (arr, TRUE); g_ptr_array_free (arr, TRUE);