gdbsupport/filestuff.h

   1 /* Low-level file-handling.
   2    Copyright (C) 2012-2020 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
  25 /* Note all the file descriptors which are open when this is called.
  26    These file descriptors will not be closed by close_most_fds.  */
  27
  28 extern void notice_open_fds (void);
  29
  30 /* Mark a file descriptor as inheritable across an exec.  */
  31
  32 extern void mark_fd_no_cloexec (int fd);
  33
  34 /* Mark a file descriptor as no longer being inheritable across an
  35    exec.  This is only meaningful when FD was previously passed to
  36    mark_fd_no_cloexec.  */
  37
  38 extern void unmark_fd_no_cloexec (int fd);
  39
  40 /* Close all open file descriptors other than those marked by
  41    'notice_open_fds', and stdin, stdout, and stderr.  Errors that
  42    occur while closing are ignored.  */
  43
  44 extern void close_most_fds (void);
  45
  46 /* Like 'open', but ensures that the returned file descriptor has the
  47    close-on-exec flag set.  */
  48
  49 extern int gdb_open_cloexec (const char *filename, int flags,
  50                              /* mode_t */ unsigned long mode);
  51
  52 /* Like mkstemp, but ensures that the file descriptor is
  53    close-on-exec.  */
  54
  55 static inline int
  56 gdb_mkostemp_cloexec (char *name_template, int flags = 0)
  57 {
  58   /* gnulib provides a mkostemp replacement if needed.  */
  59   return mkostemp (name_template, flags | O_CLOEXEC);
  60 }
  61
  62 /* Convenience wrapper for the above, which takes the filename as an
  63    std::string.  */
  64
  65 static inline int
  66 gdb_open_cloexec (const std::string &filename, int flags,
  67                   /* mode_t */ unsigned long mode)
  68 {
  69   return gdb_open_cloexec (filename.c_str (), flags, mode);
  70 }
  71
  72 struct gdb_file_deleter
  73 {
  74   void operator() (FILE *file) const
  75   {
  76     fclose (file);
  77   }
  78 };
  79
  80 /* A unique pointer to a FILE.  */
  81
  82 typedef std::unique_ptr<FILE, gdb_file_deleter> gdb_file_up;
  83
  84 /* Like 'fopen', but ensures that the returned file descriptor has the
  85    close-on-exec flag set.  */
  86
  87 extern gdb_file_up gdb_fopen_cloexec (const char *filename,
  88                                       const char *opentype);
  89
  90 /* Convenience wrapper for the above, which takes the filename as an
  91    std::string.  */
  92
  93 static inline gdb_file_up
  94 gdb_fopen_cloexec (const std::string &filename, const char *opentype)
  95 {
  96   return gdb_fopen_cloexec (filename.c_str (), opentype);
  97 }
  98
  99 /* Like 'socketpair', but ensures that the returned file descriptors
 100    have the close-on-exec flag set.  */
 101
 102 extern int gdb_socketpair_cloexec (int domain, int style, int protocol,
 103                                    int filedes[2]);
 104
 105 /* Like 'socket', but ensures that the returned file descriptor has
 106    the close-on-exec flag set.  */
 107
 108 extern int gdb_socket_cloexec (int domain, int style, int protocol);
 109
 110 /* Like 'pipe', but ensures that the returned file descriptors have
 111    the close-on-exec flag set.  */
 112
 113 extern int gdb_pipe_cloexec (int filedes[2]);
 114
 115 struct gdb_dir_deleter
 116 {
 117   void operator() (DIR *dir) const
 118   {
 119     closedir (dir);
 120   }
 121 };
 122
 123 /* A unique pointer to a DIR.  */
 124
 125 typedef std::unique_ptr<DIR, gdb_dir_deleter> gdb_dir_up;
 126
 127 /* Return true if the file NAME exists and is a regular file.
 128    If the result is false then *ERRNO_PTR is set to a useful value assuming
 129    we're expecting a regular file.  */
 130 extern bool is_regular_file (const char *name, int *errno_ptr);
 131
 132
 133 /* A cheap (as in low-quality) recursive mkdir.  Try to create all the
 134    parents directories up to DIR and DIR itself.  Stop if we hit an
 135    error along the way.  There is no attempt to remove created
 136    directories in case of failure.
 137
 138    Returns false on failure and sets errno.  */
 139
 140 extern bool mkdir_recursive (const char *dir);
 141
 142 #endif /* COMMON_FILESTUFF_H */