gdbsupport: make gdb_open_cloexec return scoped_fd

Make gdb_open_cloexec return a scoped_fd, to encourage using automatic
management of the file descriptor closing.  Except in the most trivial
cases, I changed the callers to just release the fd, which retains their
existing behavior.  That will allow the transition to using scoped_fd
more to go gradually, one caller at a time.

Change-Id: Ife022b403f96e71d5ebb4f1056ef6251b30fe554

gdb/auxv.c

@@ -46,23 +46,21 @@ procfs_xfer_auxv (gdb_byte *readbuf,
 		  ULONGEST len,
 		  ULONGEST *xfered_len)
 {
-  int fd;
   ssize_t l;
 
   std::string pathname = string_printf ("/proc/%d/auxv", inferior_ptid.pid ());
-  fd = gdb_open_cloexec (pathname, writebuf != NULL ? O_WRONLY : O_RDONLY, 0);
-  if (fd < 0)
+  scoped_fd fd
+    = gdb_open_cloexec (pathname, writebuf != NULL ? O_WRONLY : O_RDONLY, 0);
+  if (fd.get () < 0)
     return TARGET_XFER_E_IO;
 
   if (offset != (ULONGEST) 0
-      && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
+      && lseek (fd.get (), (off_t) offset, SEEK_SET) != (off_t) offset)
     l = -1;
   else if (readbuf != NULL)
-    l = read (fd, readbuf, (size_t) len);
+    l = read (fd.get (), readbuf, (size_t) len);
   else
-    l = write (fd, writebuf, (size_t) len);
-
-  (void) close (fd);
+    l = write (fd.get (), writebuf, (size_t) len);
 
   if (l < 0)
     return TARGET_XFER_E_IO;

gdb/corelow.c

@@ -437,7 +437,7 @@ core_target_open (const char *arg, int from_tty)
     flags |= O_RDWR;
   else
     flags |= O_RDONLY;
-  scratch_chan = gdb_open_cloexec (filename.get (), flags, 0);
+  scratch_chan = gdb_open_cloexec (filename.get (), flags, 0).release ();
   if (scratch_chan < 0)
     perror_with_name (filename.get ());
 

gdb/darwin-nat.c

@@ -1822,7 +1822,7 @@ may_have_sip ()
 static void
 copy_shell_to_cache (const char *shell, const std::string &new_name)
 {
-  scoped_fd from_fd (gdb_open_cloexec (shell, O_RDONLY, 0));
+  scoped_fd from_fd = gdb_open_cloexec (shell, O_RDONLY, 0);
   if (from_fd.get () < 0)
     error (_("Could not open shell (%s) for reading: %s"),
 	   shell, safe_strerror (errno));

gdb/gdb_bfd.c

@@ -541,7 +541,7 @@ gdb_bfd_open (const char *name, const char *target, int fd,
 
   if (fd == -1)
     {
-      fd = gdb_open_cloexec (name, O_RDONLY | O_BINARY, 0);
+      fd = gdb_open_cloexec (name, O_RDONLY | O_BINARY, 0).release ();
       if (fd == -1)
 	{
 	  bfd_set_error (bfd_error_system_call);

gdb/inf-child.c

@@ -261,7 +261,7 @@ inf_child_target::fileio_open (struct inferior *inf, const char *filename,
       return -1;
     }
 
-  fd = gdb_open_cloexec (filename, nat_flags, nat_mode);
+  fd = gdb_open_cloexec (filename, nat_flags, nat_mode).release ();
   if (fd == -1)
     *target_errno = host_to_fileio_error (errno);
 

gdb/linux-nat.c

@@ -3832,7 +3832,7 @@ linux_proc_xfer_memory_partial_pid (ptid_t ptid,
 		 "/proc/%d/task/%ld/mem", ptid.pid (), ptid.lwp ());
 
       last_proc_mem_file.fd
-	= gdb_open_cloexec (filename, O_RDWR | O_LARGEFILE, 0);
+	= gdb_open_cloexec (filename, O_RDWR | O_LARGEFILE, 0).release ();
 
       if (last_proc_mem_file.fd == -1)
 	{

gdb/nat/linux-namespaces.c

@@ -520,13 +520,8 @@ static ssize_t
 mnsh_handle_open (int sock, const char *filename,
 		  int flags, mode_t mode)
 {
-  int fd = gdb_open_cloexec (filename, flags, mode);
-  ssize_t result = mnsh_return_fd (sock, fd, errno);
-
-  if (fd >= 0)
-    close (fd);
-
-  return result;
+  scoped_fd fd = gdb_open_cloexec (filename, flags, mode);
+  return mnsh_return_fd (sock, fd.get (), errno);
 }
 
 /* Handle a MNSH_REQ_UNLINK message.  Must be async-signal-safe.  */
@@ -901,7 +896,7 @@ linux_mntns_access_fs (pid_t pid)
   if (ns == NULL)
     return MNSH_FS_DIRECT;
 
-  fd = gdb_open_cloexec (linux_ns_filename (ns, pid), O_RDONLY, 0);
+  fd = gdb_open_cloexec (linux_ns_filename (ns, pid), O_RDONLY, 0).release ();
   if (fd < 0)
     return MNSH_FS_ERROR;
 
@@ -968,7 +963,7 @@ linux_mntns_open_cloexec (pid_t pid, const char *filename,
     return -1;
 
   if (access == MNSH_FS_DIRECT)
-    return gdb_open_cloexec (filename, flags, mode);
+    return gdb_open_cloexec (filename, flags, mode).release ();
 
   gdb_assert (access == MNSH_FS_HELPER);
 

gdb/remote-fileio.c

@@ -425,7 +425,7 @@ remote_fileio_func_open (remote_target *remote, char *buf)
 	}
     }
 
-  fd = gdb_open_cloexec (pathname, flags, mode);
+  fd = gdb_open_cloexec (pathname, flags, mode).release ();
   if (fd < 0)
     {
       remote_fileio_return_errno (remote, -1);

gdb/ser-unix.c

@@ -75,7 +75,7 @@ static int hardwire_setstopbits (struct serial *, int);
 static int
 hardwire_open (struct serial *scb, const char *name)
 {
-  scb->fd = gdb_open_cloexec (name, O_RDWR, 0);
+  scb->fd = gdb_open_cloexec (name, O_RDWR, 0).release ();
   if (scb->fd < 0)
     return -1;
 

gdb/solib.c

@@ -257,7 +257,8 @@ solib_find_1 (const char *in_pathname, int *fd, bool is_solib)
     }
 
   /* Now see if we can open it.  */
-  found_file = gdb_open_cloexec (temp_pathname.get (), O_RDONLY | O_BINARY, 0);
+  found_file = gdb_open_cloexec (temp_pathname.get (),
+				 O_RDONLY | O_BINARY, 0).release ();
 
   /* If the search in gdb_sysroot failed, and the path name has a
      drive spec (e.g, c:/foo), try stripping ':' from the drive spec,
@@ -278,7 +279,7 @@ solib_find_1 (const char *in_pathname, int *fd, bool is_solib)
 				   in_pathname + 2, (char *) NULL));
 
       found_file = gdb_open_cloexec (temp_pathname.get (),
-				     O_RDONLY | O_BINARY, 0);
+				     O_RDONLY | O_BINARY, 0).release ();
       if (found_file < 0)
 	{
 	  /* If the search in gdb_sysroot still failed, try fully
@@ -292,7 +293,7 @@ solib_find_1 (const char *in_pathname, int *fd, bool is_solib)
 				       in_pathname + 2, (char *) NULL));
 
 	  found_file = gdb_open_cloexec (temp_pathname.get (),
-					 O_RDONLY | O_BINARY, 0);
+					 O_RDONLY | O_BINARY, 0).release ();
 	}
     }
 

gdb/source.c

@@ -832,7 +832,7 @@ openp (const char *path, openp_flags opts, const char *string,
 	{
 	  filename = (char *) alloca (strlen (string) + 1);
 	  strcpy (filename, string);
-	  fd = gdb_open_cloexec (filename, mode, 0);
+	  fd = gdb_open_cloexec (filename, mode, 0).release ();
 	  if (fd >= 0)
 	    goto done;
 	  last_errno = errno;
@@ -924,7 +924,7 @@ openp (const char *path, openp_flags opts, const char *string,
 
       if (is_regular_file (filename, &reg_file_errno))
 	{
-	  fd = gdb_open_cloexec (filename, mode, 0);
+	  fd = gdb_open_cloexec (filename, mode, 0).release ();
 	  if (fd >= 0)
 	    break;
 	  last_errno = errno;
@@ -1060,7 +1060,6 @@ find_and_open_source (const char *filename,
 {
   char *path = source_path;
   const char *p;
-  int result;
 
   /* If reading of source files is disabled then return a result indicating
      the attempt to read this source file failed.  GDB will then display
@@ -1080,12 +1079,11 @@ find_and_open_source (const char *filename,
       if (rewritten_fullname != NULL)
 	*fullname = std::move (rewritten_fullname);
 
-      result = gdb_open_cloexec (fullname->get (), OPEN_MODE, 0);
-
-      if (result >= 0)
+      scoped_fd result = gdb_open_cloexec (fullname->get (), OPEN_MODE, 0);
+      if (result.get () >= 0)
 	{
 	  *fullname = gdb_realpath (fullname->get ());
-	  return scoped_fd (result);
+	  return result;
 	}
 
       /* Didn't work -- free old one, try again.  */
@@ -1129,7 +1127,7 @@ find_and_open_source (const char *filename,
     filename = rewritten_filename.get ();
 
   /* Try to locate file using filename.  */
-  result = openp (path, OPF_SEARCH_IN_PATH | OPF_RETURN_REALPATH, filename,
+  int result = openp (path, OPF_SEARCH_IN_PATH | OPF_RETURN_REALPATH, filename,
 		      OPEN_MODE, fullname);
   if (result < 0 && dirname != NULL)
     {

gdb/top.c

@@ -335,13 +335,11 @@ ui::~ui ()
 static gdb_file_up
 open_terminal_stream (const char *name)
 {
-  int fd;
-
-  fd = gdb_open_cloexec (name, O_RDWR | O_NOCTTY, 0);
-  if (fd < 0)
+  scoped_fd fd = gdb_open_cloexec (name, O_RDWR | O_NOCTTY, 0);
+  if (fd.get () < 0)
     perror_with_name  (_("opening terminal failed"));
 
-  return gdb_file_up (fdopen (fd, "w+"));
+  return fd.to_file ("w+");
 }
 
 /* Implementation of the "new-ui" command.  */

gdb/tracefile-tfile.c

@@ -475,7 +475,7 @@ tfile_target_open (const char *arg, int from_tty)
 
   flags = O_BINARY | O_LARGEFILE;
   flags |= O_RDONLY;
-  scratch_chan = gdb_open_cloexec (filename.get (), flags, 0);
+  scratch_chan = gdb_open_cloexec (filename.get (), flags, 0).release ();
   if (scratch_chan < 0)
     perror_with_name (filename.get ());
 

gdbsupport/filestuff.cc

@@ -306,13 +306,13 @@ socket_mark_cloexec (int fd)
 
 /* See filestuff.h.  */
 
-int
+scoped_fd
 gdb_open_cloexec (const char *filename, int flags, unsigned long mode)
 {
-  int fd = open (filename, flags | O_CLOEXEC, mode);
+  scoped_fd fd (open (filename, flags | O_CLOEXEC, mode));
 
-  if (fd >= 0)
-    maybe_mark_cloexec (fd);
+  if (fd.get () >= 0)
+    maybe_mark_cloexec (fd.get ());
 
   return fd;
 }

gdbsupport/filestuff.h

@@ -22,6 +22,7 @@
 #include <dirent.h>
 #include <fcntl.h>
 #include "gdb_file.h"
+#include "scoped_fd.h"
 
 /* Note all the file descriptors which are open when this is called.
    These file descriptors will not be closed by close_most_fds.  */
@@ -47,7 +48,7 @@ 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,
+extern scoped_fd gdb_open_cloexec (const char *filename, int flags,
 				   /* mode_t */ unsigned long mode);
 
 /* Like mkstemp, but ensures that the file descriptor is
@@ -63,7 +64,7 @@ gdb_mkostemp_cloexec (char *name_template, int flags = 0)
 /* Convenience wrapper for the above, which takes the filename as an
    std::string.  */
 
-static inline int
+static inline scoped_fd
 gdb_open_cloexec (const std::string &filename, int flags,
 		  /* mode_t */ unsigned long mode)
 {

gdbsupport/scoped_mmap.cc

@@ -27,7 +27,7 @@
 scoped_mmap
 mmap_file (const char *filename)
 {
-  scoped_fd fd (gdb_open_cloexec (filename, O_RDONLY, 0));
+  scoped_fd fd = gdb_open_cloexec (filename, O_RDONLY, 0);
   if (fd.get () < 0)
     perror_with_name (("open"));