gdbsupport/filestuff.h

   1 /* Low-level file-handling.
   2    Copyright (C) 2012-2024 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 #include "scoped_fd.h"
  26
  27 /* Note all the file descriptors which are open when this is called.
  28    These file descriptors will not be closed by close_most_fds.  */
  29
  30 extern void notice_open_fds (void);
  31
  32 /* Mark a file descriptor as inheritable across an exec.  */
  33
  34 extern void mark_fd_no_cloexec (int fd);
  35
  36 /* Mark a file descriptor as no longer being inheritable across an
  37    exec.  This is only meaningful when FD was previously passed to
  38    mark_fd_no_cloexec.  */
  39
  40 extern void unmark_fd_no_cloexec (int fd);
  41
  42 /* Close all open file descriptors other than those marked by
  43    'notice_open_fds', and stdin, stdout, and stderr.  Errors that
  44    occur while closing are ignored.  */
  45
  46 extern void close_most_fds (void);
  47
  48 /* Like 'open', but ensures that the returned file descriptor has the
  49    close-on-exec flag set.  */
  50
  51 extern scoped_fd gdb_open_cloexec (const char *filename, int flags,
  52                                    /* mode_t */ unsigned long mode);
  53
  54 /* Like mkstemp, but ensures that the file descriptor is
  55    close-on-exec.  */
  56
  57 static inline scoped_fd
  58 gdb_mkostemp_cloexec (char *name_template, int flags = 0)
  59 {
  60   /* gnulib provides a mkostemp replacement if needed.  */
  61   return scoped_fd (mkostemp (name_template, flags | O_CLOEXEC));
  62 }
  63
  64 /* Convenience wrapper for the above, which takes the filename as an
  65    std::string.  */
  66
  67 static inline scoped_fd
  68 gdb_open_cloexec (const std::string &filename, int flags,
  69                   /* mode_t */ unsigned long mode)
  70 {
  71   return gdb_open_cloexec (filename.c_str (), flags, mode);
  72 }
  73
  74 /* Like 'fopen', but ensures that the returned file descriptor has the
  75    close-on-exec flag set.  */
  76
  77 extern gdb_file_up gdb_fopen_cloexec (const char *filename,
  78                                       const char *opentype);
  79
  80 /* Convenience wrapper for the above, which takes the filename as an
  81    std::string.  */
  82
  83 static inline gdb_file_up
  84 gdb_fopen_cloexec (const std::string &filename, const char *opentype)
  85 {
  86   return gdb_fopen_cloexec (filename.c_str (), opentype);
  87 }
  88
  89 /* Like 'socketpair', but ensures that the returned file descriptors
  90    have the close-on-exec flag set.  */
  91
  92 extern int gdb_socketpair_cloexec (int domain, int style, int protocol,
  93                                    int filedes[2]);
  94
  95 /* Like 'socket', but ensures that the returned file descriptor has
  96    the close-on-exec flag set.  */
  97
  98 extern int gdb_socket_cloexec (int domain, int style, int protocol);
  99
 100 /* Like 'pipe', but ensures that the returned file descriptors have
 101    the close-on-exec flag set.  */
 102
 103 extern int gdb_pipe_cloexec (int filedes[2]);
 104
 105 struct gdb_dir_deleter
 106 {
 107   void operator() (DIR *dir) const
 108   {
 109     closedir (dir);
 110   }
 111 };
 112
 113 /* A unique pointer to a DIR.  */
 114
 115 typedef std::unique_ptr<DIR, gdb_dir_deleter> gdb_dir_up;
 116
 117 /* Return true if the file NAME exists and is a regular file.
 118    If the result is false then *ERRNO_PTR is set to a useful value assuming
 119    we're expecting a regular file.  */
 120 extern bool is_regular_file (const char *name, int *errno_ptr);
 121
 122
 123 /* A cheap (as in low-quality) recursive mkdir.  Try to create all the
 124    parents directories up to DIR and DIR itself.  Stop if we hit an
 125    error along the way.  There is no attempt to remove created
 126    directories in case of failure.
 127
 128    Returns false on failure and sets errno.  */
 129
 130 extern bool mkdir_recursive (const char *dir);
 131
 132 /* Read the entire content of file PATH into an std::string.  */
 133
 134 extern std::optional<std::string> read_text_file_to_string (const char *path);
 135
 136 /* Read the remaining content from FILE into an std::string.  */
 137
 138 extern std::string read_remainder_of_file (FILE *file);
 139
 140 #endif /* COMMON_FILESTUFF_H */