gdbsupport/filestuff.h

   1 /* Low-level file-handling.
   2    Copyright (C) 2012-2021 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef COMMON_FILESTUFF_H
  20 #define COMMON_FILESTUFF_H
  21
  22 #include <dirent.h>
  23 #include <fcntl.h>
  24 #include "gdb_file.h"
  25
  26 /* Note all the file descriptors which are open when this is called.
  27    These file descriptors will not be closed by close_most_fds.  */
  28
  29 extern void notice_open_fds (void);
  30
  31 /* Mark a file descriptor as inheritable across an exec.  */
  32
  33 extern void mark_fd_no_cloexec (int fd);
  34
  35 /* Mark a file descriptor as no longer being inheritable across an
  36    exec.  This is only meaningful when FD was previously passed to
  37    mark_fd_no_cloexec.  */
  38
  39 extern void unmark_fd_no_cloexec (int fd);
  40
  41 /* Close all open file descriptors other than those marked by
  42    'notice_open_fds', and stdin, stdout, and stderr.  Errors that
  43    occur while closing are ignored.  */
  44
  45 extern void close_most_fds (void);
  46
  47 /* Like 'open', but ensures that the returned file descriptor has the
  48    close-on-exec flag set.  */
  49
  50 extern int gdb_open_cloexec (const char *filename, int flags,
  51                              /* mode_t */ unsigned long mode);
  52
  53 /* Like mkstemp, but ensures that the file descriptor is
  54    close-on-exec.  */
  55
  56 static inline int
  57 gdb_mkostemp_cloexec (char *name_template, int flags = 0)
  58 {
  59   /* gnulib provides a mkostemp replacement if needed.  */
  60   return mkostemp (name_template, flags | O_CLOEXEC);
  61 }
  62
  63 /* Convenience wrapper for the above, which takes the filename as an
  64    std::string.  */
  65
  66 static inline int
  67 gdb_open_cloexec (const std::string &filename, int flags,
  68                   /* mode_t */ unsigned long mode)
  69 {
  70   return gdb_open_cloexec (filename.c_str (), flags, mode);
  71 }
  72
  73 /* Like 'fopen', but ensures that the returned file descriptor has the
  74    close-on-exec flag set.  */
  75
  76 extern gdb_file_up gdb_fopen_cloexec (const char *filename,
  77                                       const char *opentype);
  78
  79 /* Convenience wrapper for the above, which takes the filename as an
  80    std::string.  */
  81
  82 static inline gdb_file_up
  83 gdb_fopen_cloexec (const std::string &filename, const char *opentype)
  84 {
  85   return gdb_fopen_cloexec (filename.c_str (), opentype);
  86 }
  87
  88 /* Like 'socketpair', but ensures that the returned file descriptors
  89    have the close-on-exec flag set.  */
  90
  91 extern int gdb_socketpair_cloexec (int domain, int style, int protocol,
  92                                    int filedes[2]);
  93
  94 /* Like 'socket', but ensures that the returned file descriptor has
  95    the close-on-exec flag set.  */
  96
  97 extern int gdb_socket_cloexec (int domain, int style, int protocol);
  98
  99 /* Like 'pipe', but ensures that the returned file descriptors have
 100    the close-on-exec flag set.  */
 101
 102 extern int gdb_pipe_cloexec (int filedes[2]);
 103
 104 struct gdb_dir_deleter
 105 {
 106   void operator() (DIR *dir) const
 107   {
 108     closedir (dir);
 109   }
 110 };
 111
 112 /* A unique pointer to a DIR.  */
 113
 114 typedef std::unique_ptr<DIR, gdb_dir_deleter> gdb_dir_up;
 115
 116 /* Return true if the file NAME exists and is a regular file.
 117    If the result is false then *ERRNO_PTR is set to a useful value assuming
 118    we're expecting a regular file.  */
 119 extern bool is_regular_file (const char *name, int *errno_ptr);
 120
 121
 122 /* A cheap (as in low-quality) recursive mkdir.  Try to create all the
 123    parents directories up to DIR and DIR itself.  Stop if we hit an
 124    error along the way.  There is no attempt to remove created
 125    directories in case of failure.
 126
 127    Returns false on failure and sets errno.  */
 128
 129 extern bool mkdir_recursive (const char *dir);
 130
 131 #endif /* COMMON_FILESTUFF_H */