PR gdb/7912:

	* Makefile.in (SFILES): Add filestuff.c
	(COMMON_OBS): Add filestuff.o.
	(filestuff.o): New target.
	* auto-load.c (auto_load_objfile_script_1): Use
	gdb_fopen_cloexec.
	* auxv.c (procfs_xfer_auxv): Use gdb_open_cloexec.
	* cli/cli-cmds.c (shell_escape): Call close_most_fds.
	* cli/cli-dump.c (fopen_with_cleanup): Use gdb_fopen_cloexec.
	* common/agent.c (gdb_connect_sync_socket): Use
	gdb_socket_cloexec.
	* common/filestuff.c: New file.
	* common/filestuff.h: New file.
	* common/linux-osdata.c (linux_common_core_of_thread)
	(command_from_pid, commandline_from_pid, print_source_lines)
	(linux_xfer_osdata_shm, linux_xfer_osdata_sem)
	(linux_xfer_osdata_msg, linux_xfer_osdata_modules): Use
	gdb_fopen_cloexec.
	* common/linux-procfs.c (linux_proc_get_int)
	(linux_proc_pid_has_state): Use gdb_fopen_cloexec.
	* config.in, configure: Rebuild.
	* configure.ac: Don't check for sys/socket.h.  Check for
	fdwalk, pipe2.
	* corelow.c (core_open): Use gdb_open_cloexec.
	* dwarf2read.c (write_psymtabs_to_index): Use gdb_fopen_cloexec.
	* fork-child.c (fork_inferior): Call close_most_fds.
	* gdb_bfd.c (gdb_bfd_open): Use gdb_open_cloexec.
	* inf-child.c (inf_child_fileio_readlink): Use gdb_open_cloexec.
	* linux-nat.c (linux_nat_thread_name, linux_proc_pending_signals):
	Use gdb_fopen_cloexec.
	(linux_proc_xfer_partial, linux_proc_xfer_spu): Use
	gdb_open_cloexec.
	(linux_async_pipe): Use gdb_pipe_cloexec.
	* remote-fileio.c (remote_fileio_func_open): Use
	gdb_open_cloexec.
	* remote.c (remote_file_put, remote_file_get): Use
	gdb_fopen_cloexec.
	* ser-pipe.c (pipe_open): Use gdb_socketpair_cloexec,
	close_most_fds.
	* ser-tcp.c (net_open): Use gdb_socket_cloexec.
	* ser-unix.c (hardwire_open): Use gdb_open_cloexec.
	* solib.c (solib_find): Use gdb_open_cloexec.
	* source.c (openp, find_and_open_source): Use gdb_open_cloexec.
	* tracepoint.c (tfile_start): Use gdb_fopen_cloexec.
	(tfile_open): Use gdb_open_cloexec.
	* tui/tui-io.c (tui_initialize_io): Use gdb_pipe_cloexec.
	* ui-file.c (gdb_fopen): Use gdb_fopen_cloexec.
	* xml-support.c (xml_fetch_content_from_file): Use
	gdb_fopen_cloexec.
	* main.c (captured_main): Call notice_open_fds.
gdbserver
	* Makefile.in (SFILES): Add filestuff.c.
	(OBS): Add filestuff.o.
	(filestuff.o): New target.
	* config.in, configure: Rebuild.
	* configure.ac: Check for fdwalk, pipe2.

5 files changed, 427 insertions, 11 deletions

diff --git a/gdb/common/agent.c b/gdb/common/agent.c
index f7bedc2..99cef4f 100644
--- a/gdb/common/agent.c
+++ b/gdb/common/agent.c
@@ -28,6 +28,7 @@
 #include <string.h>
 #include <unistd.h>
 #include "agent.h"
+#include "filestuff.h"
 
 int debug_agent = 0;
 
@@ -168,7 +169,7 @@ gdb_connect_sync_socket (int pid)
   if (res >= UNIX_PATH_MAX)
     return -1;
 
-  res = fd = socket (PF_UNIX, SOCK_STREAM, 0);
+  res = fd = gdb_socket_cloexec (PF_UNIX, SOCK_STREAM, 0);
   if (res == -1)
     {
       warning (_("error opening sync socket: %s"), strerror (errno));
diff --git a/gdb/common/filestuff.c b/gdb/common/filestuff.c
new file mode 100644
index 0000000..2cc1c4d
--- /dev/null
+++ b/gdb/common/filestuff.c
@@ -0,0 +1,354 @@
+/* Low-level file-handling.
+   Copyright (C) 2012, 2013 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifdef GDBSERVER
+#include "server.h"
+#else
+#include "defs.h"
+#include "gdb_string.h"
+#endif
+#include "filestuff.h"
+#include "gdb_vecs.h"
+
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif /* HAVE_SYS_RESOURCE_H */
+
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+
+#ifndef SOCK_CLOEXEC
+#define SOCK_CLOEXEC 0
+#endif
+
+
+
+#ifndef HAVE_FDWALK
+
+#include <dirent.h>
+
+/* Replacement for fdwalk, if the system doesn't define it.  Walks all
+   open file descriptors (though this implementation may walk closed
+   ones as well, depending on the host platform's capabilities) and
+   call FUNC with ARG.  If FUNC returns non-zero, stops immediately
+   and returns the same value.  Otherwise, returns zero when
+   finished.  */
+
+static int
+fdwalk (int (*func) (void *, int), void *arg)
+{
+  /* Checking __linux__ isn't great but it isn't clear what would be
+     better.  There doesn't seem to be a good way to check for this in
+     configure.  */
+#ifdef __linux__
+  DIR *dir;
+
+  dir = opendir ("/proc/self/fd");
+  if (dir != NULL)
+    {
+      struct dirent *entry;
+      int result = 0;
+
+      for (entry = readdir (dir); entry != NULL; entry = readdir (dir))
+	{
+	  long fd;
+	  char *tail;
+	  int result;
+
+	  errno = 0;
+	  fd = strtol (entry->d_name, &tail, 10);
+	  if (*tail != '\0' || errno != 0)
+	    continue;
+	  if ((int) fd != fd)
+	    {
+	      /* What can we do here really?  */
+	      continue;
+	    }
+
+	  if (fd == dirfd (dir))
+	    continue;
+
+	  result = func (arg, fd);
+	  if (result != 0)
+	    break;
+	}
+
+      closedir (dir);
+      return result;
+    }
+  /* We may fall through to the next case.  */
+#endif
+
+  {
+    int max, fd;
+
+#ifdef HAVE_GETRLIMIT
+    struct rlimit rlim;
+
+    if (getrlimit (RLIMIT_NOFILE, &rlim) == 0 && rlim.rlim_max != RLIM_INFINITY)
+      max = rlim.rlim_max;
+    else
+#endif
+      {
+#ifdef _SC_OPEN_MAX
+	max = sysconf (_SC_OPEN_MAX);
+#else
+	/* Whoops.  */
+	return 0;
+#endif /* _SC_OPEN_MAX */
+      }
+
+    for (fd = 0; fd < max; ++fd)
+      {
+	struct stat sb;
+	int result;
+
+	/* Only call FUNC for open fds.  */
+	if (fstat (fd, &sb) == -1)
+	  continue;
+
+	result = func (arg, fd);
+	if (result != 0)
+	  return result;
+      }
+
+    return 0;
+  }
+}
+
+#endif /* HAVE_FDWALK */
+
+
+
+/* A VEC holding all the fds open when notice_open_fds was called.  We
+   don't use a hashtab because libiberty isn't linked into gdbserver;
+   and anyway we don't expect there to be many open fds.  */
+
+DEF_VEC_I (int);
+
+static VEC (int) *open_fds;
+
+/* An fdwalk callback function used by notice_open_fds.  It puts the
+   given file descriptor into the vec.  */
+
+static int
+do_mark_open_fd (void *ignore, int fd)
+{
+  VEC_safe_push (int, open_fds, fd);
+  return 0;
+}
+
+/* See filestuff.h.  */
+
+void
+notice_open_fds (void)
+{
+  fdwalk (do_mark_open_fd, NULL);
+}
+
+/* Helper function for close_most_fds that closes the file descriptor
+   if appropriate.  */
+
+static int
+do_close (void *ignore, int fd)
+{
+  int i, val;
+
+  for (i = 0; VEC_iterate (int, open_fds, i, val); ++i)
+    {
+      if (fd == val)
+	{
+	  /* Keep this one open.  */
+	  return 0;
+	}
+    }
+
+  close (fd);
+  return 0;
+}
+
+/* See filestuff.h.  */
+
+void
+close_most_fds (void)
+{
+  fdwalk (do_close, NULL);
+}
+
+
+
+/* This is a tri-state flag.  When zero it means we haven't yet tried
+   O_CLOEXEC.  When positive it means that O_CLOEXEC works on this
+   host.  When negative, it means that O_CLOEXEC doesn't work.  We
+   track this state because, while gdb might have been compiled
+   against a libc that supplies O_CLOEXEC, there is no guarantee that
+   the kernel supports it.  */
+
+static int trust_o_cloexec;
+
+/* Mark FD as close-on-exec, ignoring errors.  Update
+   TRUST_O_CLOEXEC.  */
+
+static void
+mark_cloexec (int fd)
+{
+  int old = fcntl (fd, F_GETFD, 0);
+
+  if (old != -1)
+    {
+      fcntl (fd, F_SETFD, old | FD_CLOEXEC);
+
+      if (trust_o_cloexec == 0)
+	{
+	  if ((old & FD_CLOEXEC) != 0)
+	    trust_o_cloexec = 1;
+	  else
+	    trust_o_cloexec = -1;
+	}
+    }
+}
+
+/* Depending on TRUST_O_CLOEXEC, mark FD as close-on-exec.  */
+
+static void
+maybe_mark_cloexec (int fd)
+{
+  if (trust_o_cloexec <= 0)
+    mark_cloexec (fd);
+}
+
+/* Like maybe_mark_cloexec, but for callers that use SOCK_CLOEXEC.  */
+
+static void
+socket_mark_cloexec (int fd)
+{
+  if (SOCK_CLOEXEC == 0 || trust_o_cloexec <= 0)
+    mark_cloexec (fd);
+}
+
+
+
+/* See filestuff.h.  */
+
+int
+gdb_open_cloexec (const char *filename, int flags, mode_t mode)
+{
+  int fd = open (filename, flags | O_CLOEXEC, mode);
+
+  if (fd >= 0)
+    maybe_mark_cloexec (fd);
+
+  return fd;
+}
+
+/* See filestuff.h.  */
+
+FILE *
+gdb_fopen_cloexec (const char *filename, const char *opentype)
+{
+  FILE *result = NULL;
+  static int fopen_e_ever_failed;
+
+  if (!fopen_e_ever_failed)
+    {
+      char *copy;
+
+      copy = alloca (strlen (opentype) + 2);
+      strcpy (copy, opentype);
+      /* This is a glibc extension but we try it unconditionally on
+	 this path.  */
+      strcat (copy, "e");
+      result = fopen (filename, copy);
+    }
+
+  if (result == NULL)
+    {
+      /* Fallback.  */
+      result = fopen (filename, opentype);
+      if (result != NULL)
+	fopen_e_ever_failed = 1;
+    }
+
+  if (result != NULL)
+    maybe_mark_cloexec (fileno (result));
+
+  return result;
+}
+
+/* See filestuff.h.  */
+
+int
+gdb_socketpair_cloexec (int namespace, int style, int protocol, int filedes[2])
+{
+  int result = socketpair (namespace, style | SOCK_CLOEXEC, protocol, filedes);
+
+  if (result != -1)
+    {
+      socket_mark_cloexec (filedes[0]);
+      socket_mark_cloexec (filedes[1]);
+    }
+
+  return result;
+}
+
+/* See filestuff.h.  */
+
+int
+gdb_socket_cloexec (int namespace, int style, int protocol)
+{
+  int result = socket (namespace, style | SOCK_CLOEXEC, protocol);
+
+  if (result != -1)
+    socket_mark_cloexec (result);
+
+  return result;
+}
+
+/* See filestuff.h.  */
+
+int
+gdb_pipe_cloexec (int filedes[2])
+{
+  int result;
+
+#ifdef HAVE_PIPE2
+  result = pipe2 (filedes, O_CLOEXEC);
+  if (result != -1)
+    {
+      maybe_mark_cloexec (filedes[0]);
+      maybe_mark_cloexec (filedes[1]);
+    }
+#else
+  result = pipe (filedes);
+  if (result != -1)
+    {
+      mark_cloexec (filedes[0]);
+      mark_cloexec (filedes[1]);
+    }
+#endif
+
+  return result;
+}
diff --git a/gdb/common/filestuff.h b/gdb/common/filestuff.h
new file mode 100644
index 0000000..747bff2
--- /dev/null
+++ b/gdb/common/filestuff.h
@@ -0,0 +1,59 @@
+/* Low-level file-handling.
+   Copyright (C) 2012, 2013 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef FILESTUFF_H
+#define FILESTUFF_H
+
+/* Note all the file descriptors which are open when this is called.
+   These file descriptors will not be closed by close_most_fds.  */
+
+extern void notice_open_fds (void);
+
+/* Close all open file descriptors other than those marked by
+   'notice_open_fds', and stdin, stdout, and stderr.  Errors that
+   occur while closing are ignored.  */
+
+extern void close_most_fds (void);
+
+/* Like 'open', but ensures that the returned file descriptor has the
+   close-on-exec flag set.  */
+
+extern int gdb_open_cloexec (const char *filename, int flags, mode_t mode);
+
+/* Like 'fopen', but ensures that the returned file descriptor has the
+   close-on-exec flag set.  */
+
+extern FILE *gdb_fopen_cloexec (const char *filename, const char *opentype);
+
+/* Like 'socketpair', but ensures that the returned file descriptors
+   have the close-on-exec flag set.  */
+
+extern int gdb_socketpair_cloexec (int namespace, int style, int protocol,
+				   int filedes[2]);
+
+/* Like 'socket', but ensures that the returned file descriptor has
+   the close-on-exec flag set.  */
+
+extern int gdb_socket_cloexec (int namespace, int style, int protocol);
+
+/* Like 'pipe', but ensures that the returned file descriptors have
+   the close-on-exec flag set.  */
+
+extern int gdb_pipe_cloexec (int filedes[2]);
+
+#endif /* FILESTUFF_H */
diff --git a/gdb/common/linux-osdata.c b/gdb/common/linux-osdata.c
index d55470b..9723839 100644
--- a/gdb/common/linux-osdata.c
+++ b/gdb/common/linux-osdata.c
@@ -44,6 +44,7 @@
 #include "gdb_assert.h"
 #include "gdb_dirent.h"
 #include "gdb_stat.h"
+#include "filestuff.h"
 
 /* Define PID_T to be a fixed size that is at least as large as pid_t,
    so that reading pid values embedded in /proc works
@@ -76,7 +77,7 @@ linux_common_core_of_thread (ptid_t ptid)
 
   sprintf (filename, "/proc/%lld/task/%lld/stat",
 	   (PID_T) ptid_get_pid (ptid), (PID_T) ptid_get_lwp (ptid));
-  f = fopen (filename, "r");
+  f = gdb_fopen_cloexec (filename, "r");
   if (!f)
     return -1;
 
@@ -125,7 +126,7 @@ static void
 command_from_pid (char *command, int maxlen, PID_T pid)
 {
   char *stat_path = xstrprintf ("/proc/%lld/stat", pid); 
-  FILE *fp = fopen (stat_path, "r");
+  FILE *fp = gdb_fopen_cloexec (stat_path, "r");
   
   command[0] = '\0';
  
@@ -165,7 +166,7 @@ commandline_from_pid (PID_T pid)
 {
   char *pathname = xstrprintf ("/proc/%lld/cmdline", pid);
   char *commandline = NULL;
-  FILE *f = fopen (pathname, "r");
+  FILE *f = gdb_fopen_cloexec (pathname, "r");
 
   if (f)
     {
@@ -860,7 +861,7 @@ print_sockets (unsigned short family, int tcp, struct buffer *buffer)
   else
     return;
 
-  fp = fopen (proc_file, "r");
+  fp = gdb_fopen_cloexec (proc_file, "r");
   if (fp)
     {
       char buf[8192];
@@ -1088,7 +1089,7 @@ linux_xfer_osdata_shm (gdb_byte *readbuf,
       buffer_init (&buffer);
       buffer_grow_str (&buffer, "<osdata type=\"shared memory\">\n");
 
-      fp = fopen ("/proc/sysvipc/shm", "r");
+      fp = gdb_fopen_cloexec ("/proc/sysvipc/shm", "r");
       if (fp)
 	{
 	  char buf[8192];
@@ -1216,7 +1217,7 @@ linux_xfer_osdata_sem (gdb_byte *readbuf,
       buffer_init (&buffer);
       buffer_grow_str (&buffer, "<osdata type=\"semaphores\">\n");
 
-      fp = fopen ("/proc/sysvipc/sem", "r");
+      fp = gdb_fopen_cloexec ("/proc/sysvipc/sem", "r");
       if (fp)
 	{
 	  char buf[8192];
@@ -1328,7 +1329,7 @@ linux_xfer_osdata_msg (gdb_byte *readbuf,
       buffer_init (&buffer);
       buffer_grow_str (&buffer, "<osdata type=\"message queues\">\n");
       
-      fp = fopen ("/proc/sysvipc/msg", "r");
+      fp = gdb_fopen_cloexec ("/proc/sysvipc/msg", "r");
       if (fp)
 	{
 	  char buf[8192];
@@ -1454,7 +1455,7 @@ linux_xfer_osdata_modules (gdb_byte *readbuf,
       buffer_init (&buffer);
       buffer_grow_str (&buffer, "<osdata type=\"modules\">\n");
 
-      fp = fopen ("/proc/modules", "r");
+      fp = gdb_fopen_cloexec ("/proc/modules", "r");
       if (fp)
 	{
 	  char buf[8192];
diff --git a/gdb/common/linux-procfs.c b/gdb/common/linux-procfs.c
index f5dccfd..583ec98 100644
--- a/gdb/common/linux-procfs.c
+++ b/gdb/common/linux-procfs.c
@@ -24,6 +24,7 @@
 #endif
 
 #include "linux-procfs.h"
+#include "filestuff.h"
 
 /* Return the TGID of LWPID from /proc/pid/status.  Returns -1 if not
    found.  */
@@ -37,7 +38,7 @@ linux_proc_get_int (pid_t lwpid, const char *field)
   int retval = -1;
 
   snprintf (buf, sizeof (buf), "/proc/%d/status", (int) lwpid);
-  status_file = fopen (buf, "r");
+  status_file = gdb_fopen_cloexec (buf, "r");
   if (status_file == NULL)
     {
       warning (_("unable to open /proc file '%s'"), buf);
@@ -83,7 +84,7 @@ linux_proc_pid_has_state (pid_t pid, const char *state)
   int have_state;
 
   xsnprintf (buffer, sizeof (buffer), "/proc/%d/status", (int) pid);
-  procfile = fopen (buffer, "r");
+  procfile = gdb_fopen_cloexec (buffer, "r");
   if (procfile == NULL)
     {
       warning (_("unable to open /proc file '%s'"), buffer);