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1 706 jeremybenn
------------------------------------------------------------------------------
2
--                                                                          --
3
--                         GNAT COMPILER COMPONENTS                         --
4
--                                                                          --
5
--                        S Y S T E M . O S _ L I B                         --
6
--                                                                          --
7
--                                 S p e c                                  --
8
--                                                                          --
9
--          Copyright (C) 1995-2012, Free Software Foundation, Inc.         --
10
--                                                                          --
11
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12
-- terms of the  GNU General Public License as published  by the Free Soft- --
13
-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
14
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16
-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
17
--                                                                          --
18
-- As a special exception under Section 7 of GPL version 3, you are granted --
19
-- additional permissions described in the GCC Runtime Library Exception,   --
20
-- version 3.1, as published by the Free Software Foundation.               --
21
--                                                                          --
22
-- You should have received a copy of the GNU General Public License and    --
23
-- a copy of the GCC Runtime Library Exception along with this program;     --
24
-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25
-- <http://www.gnu.org/licenses/>.                                          --
26
--                                                                          --
27
-- GNAT was originally developed  by the GNAT team at  New York University. --
28
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29
--                                                                          --
30
------------------------------------------------------------------------------
31
 
32
--  Operating system interface facilities
33
 
34
--  This package contains types and procedures for interfacing to the
35
--  underlying OS. It is used by the GNAT compiler and by tools associated
36
--  with the GNAT compiler, and therefore works for the various operating
37
--  systems to which GNAT has been ported. This package will undoubtedly grow
38
--  as new services are needed by various tools.
39
 
40
--  This package tends to use fairly low-level Ada in order to not bring in
41
--  large portions of the RTL. For example, functions return access to string
42
--  as part of avoiding functions returning unconstrained types.
43
 
44
--  Except where specifically noted, these routines are portable across all
45
--  GNAT implementations on all supported operating systems.
46
 
47
--  Note: this package is in the System hierarchy so that it can be directly
48
--  be used by other predefined packages. User access to this package is via
49
--  a renaming of this package in GNAT.OS_Lib (file g-os_lib.ads).
50
 
51
pragma Compiler_Unit;
52
 
53
with System;
54
with System.Strings;
55
 
56
package System.OS_Lib is
57
   pragma Elaborate_Body (OS_Lib);
58
 
59
   -----------------------
60
   -- String Operations --
61
   -----------------------
62
 
63
   --  These are reexported from package Strings (which was introduced to
64
   --  avoid different packages declaring different types unnecessarily).
65
   --  See package System.Strings for details.
66
 
67
   subtype String_Access is Strings.String_Access;
68
 
69
   function "=" (Left, Right : String_Access) return Boolean
70
     renames Strings."=";
71
 
72
   procedure Free (X : in out String_Access) renames Strings.Free;
73
 
74
   subtype String_List is Strings.String_List;
75
 
76
   function "=" (Left, Right : String_List) return Boolean
77
     renames Strings."=";
78
 
79
   function "&" (Left : String_Access; Right : String_Access)
80
     return String_List renames Strings."&";
81
   function "&" (Left : String_Access; Right : String_List)
82
     return String_List renames Strings."&";
83
   function "&" (Left : String_List; Right : String_Access)
84
     return String_List renames Strings."&";
85
   function "&" (Left : String_List; Right : String_List)
86
     return String_List renames Strings."&";
87
 
88
   subtype String_List_Access is Strings.String_List_Access;
89
 
90
   function "=" (Left, Right : String_List_Access) return Boolean
91
     renames Strings."=";
92
 
93
   procedure Free (Arg : in out String_List_Access)
94
     renames Strings.Free;
95
 
96
   ---------------------
97
   -- Time/Date Stuff --
98
   ---------------------
99
 
100
   type OS_Time is private;
101
   --  The OS's notion of time is represented by the private type OS_Time.
102
   --  This is the type returned by the File_Time_Stamp functions to obtain
103
   --  the time stamp of a specified file. Functions and a procedure (modeled
104
   --  after the similar subprograms in package Calendar) are provided for
105
   --  extracting information from a value of this type. Although these are
106
   --  called GM, the intention is not that they provide GMT times in all
107
   --  cases but rather the actual (time-zone independent) time stamp of the
108
   --  file (of course in Unix systems, this *is* in GMT form).
109
 
110
   Invalid_Time : constant OS_Time;
111
   --  A special unique value used to flag an invalid time stamp value
112
 
113
   subtype Year_Type   is Integer range 1900 .. 2099;
114
   subtype Month_Type  is Integer range    1 ..   12;
115
   subtype Day_Type    is Integer range    1 ..   31;
116
   subtype Hour_Type   is Integer range    0 ..   23;
117
   subtype Minute_Type is Integer range    0 ..   59;
118
   subtype Second_Type is Integer range    0 ..   59;
119
   --  Declarations similar to those in Calendar, breaking down the time
120
 
121
   function Current_Time return OS_Time;
122
   --  Return the system clock value as OS_Time
123
 
124
   function GM_Year    (Date : OS_Time) return Year_Type;
125
   function GM_Month   (Date : OS_Time) return Month_Type;
126
   function GM_Day     (Date : OS_Time) return Day_Type;
127
   function GM_Hour    (Date : OS_Time) return Hour_Type;
128
   function GM_Minute  (Date : OS_Time) return Minute_Type;
129
   function GM_Second  (Date : OS_Time) return Second_Type;
130
   --  Functions to extract information from OS_Time value
131
 
132
   function "<"  (X, Y : OS_Time) return Boolean;
133
   function ">"  (X, Y : OS_Time) return Boolean;
134
   function ">=" (X, Y : OS_Time) return Boolean;
135
   function "<=" (X, Y : OS_Time) return Boolean;
136
   --  Basic comparison operators on OS_Time with obvious meanings. Note that
137
   --  these have Intrinsic convention, so for example it is not permissible
138
   --  to create accesses to any of these functions.
139
 
140
   procedure GM_Split
141
     (Date   : OS_Time;
142
      Year   : out Year_Type;
143
      Month  : out Month_Type;
144
      Day    : out Day_Type;
145
      Hour   : out Hour_Type;
146
      Minute : out Minute_Type;
147
      Second : out Second_Type);
148
   --  Analogous to the Split routine in Ada.Calendar, takes an OS_Time and
149
   --  provides a representation of it as a set of component parts, to be
150
   --  interpreted as a date point in UTC.
151
 
152
   ----------------
153
   -- File Stuff --
154
   ----------------
155
 
156
   --  These routines give access to the open/creat/close/read/write level of
157
   --  I/O routines in the typical C library (these functions are not part of
158
   --  the ANSI C standard, but are typically available in all systems). See
159
   --  also package Interfaces.C_Streams for access to the stream level
160
   --  routines.
161
 
162
   --  Note on file names. If a file name is passed as type String in any of
163
   --  the following specifications, then the name is a normal Ada string and
164
   --  need not be NUL-terminated. However, a trailing NUL character is
165
   --  permitted, and will be ignored (more accurately, the NUL and any
166
   --  characters that follow it will be ignored).
167
 
168
   type File_Descriptor is new Integer;
169
   --  Corresponds to the int file handle values used in the C routines
170
 
171
   Standin  : constant File_Descriptor := 0;
172
   Standout : constant File_Descriptor := 1;
173
   Standerr : constant File_Descriptor := 2;
174
   --  File descriptors for standard input output files
175
 
176
   Invalid_FD : constant File_Descriptor := -1;
177
   --  File descriptor returned when error in opening/creating file
178
 
179
   type Mode is (Binary, Text);
180
   for Mode'Size use Integer'Size;
181
   for Mode use (Binary => 0, Text => 1);
182
   --  Used in all the Open and Create calls to specify if the file is to be
183
   --  opened in binary mode or text mode. In systems like Unix, this has no
184
   --  effect, but in systems capable of text mode translation, the use of
185
   --  Text as the mode parameter causes the system to do CR/LF translation
186
   --  and also to recognize the DOS end of file character on input. The use
187
   --  of Text where appropriate allows programs to take a portable Unix view
188
   --  of DOS-format files and process them appropriately.
189
 
190
   function Open_Read
191
     (Name  : String;
192
      Fmode : Mode) return File_Descriptor;
193
   --  Open file Name for reading, returning file descriptor File descriptor
194
   --  returned is Invalid_FD if file cannot be opened.
195
 
196
   function Open_Read_Write
197
     (Name  : String;
198
      Fmode : Mode) return File_Descriptor;
199
   --  Open file Name for both reading and writing, returning file descriptor.
200
   --  File descriptor returned is Invalid_FD if file cannot be opened.
201
 
202
   function Create_File
203
     (Name  : String;
204
      Fmode : Mode) return File_Descriptor;
205
   --  Creates new file with given name for writing, returning file descriptor
206
   --  for subsequent use in Write calls. If the file already exists, it is
207
   --  overwritten. File descriptor returned is Invalid_FD if file cannot be
208
   --  successfully created.
209
 
210
   function Create_Output_Text_File (Name : String) return File_Descriptor;
211
   --  Creates new text file with given name suitable to redirect standard
212
   --  output, returning file descriptor. File descriptor returned is
213
   --  Invalid_FD if file cannot be successfully created.
214
 
215
   function Create_New_File
216
     (Name  : String;
217
      Fmode : Mode) return File_Descriptor;
218
   --  Create new file with given name for writing, returning file descriptor
219
   --  for subsequent use in Write calls. This differs from Create_File in
220
   --  that it fails if the file already exists. File descriptor returned is
221
   --  Invalid_FD if the file exists or cannot be created.
222
 
223
   Temp_File_Len : constant Integer := 12;
224
   --  Length of name returned by Create_Temp_File call (GNAT-XXXXXX & NUL)
225
 
226
   subtype Temp_File_Name is String (1 .. Temp_File_Len);
227
   --  String subtype set by Create_Temp_File
228
 
229
   procedure Create_Temp_File
230
     (FD   : out File_Descriptor;
231
      Name : out Temp_File_Name);
232
   --  Create and open for writing a temporary file in the current working
233
   --  directory. The name of the file and the File Descriptor are returned.
234
   --  The File Descriptor returned is Invalid_FD in the case of failure. No
235
   --  mode parameter is provided. Since this is a temporary file, there is no
236
   --  point in doing text translation on it.
237
   --
238
   --  On some operating systems, the maximum number of temp files that can be
239
   --  created with this procedure may be limited. When the maximum is reached,
240
   --  this procedure returns Invalid_FD. On some operating systems, there may
241
   --  be a race condition between processes trying to create temp files at the
242
   --  same time in the same directory using this procedure.
243
 
244
   procedure Create_Temp_File
245
     (FD   : out File_Descriptor;
246
      Name : out String_Access);
247
   --  Create and open for writing a temporary file in the current working
248
   --  directory. The name of the file and the File Descriptor are returned.
249
   --  It is the responsibility of the caller to deallocate the access value
250
   --  returned in Name.
251
   --
252
   --  The file is opened in binary mode (no text translation).
253
   --
254
   --  This procedure will always succeed if the current working directory is
255
   --  writable. If the current working directory is not writable, then
256
   --  Invalid_FD is returned for the file descriptor and null for the Name.
257
   --  There is no race condition problem between processes trying to create
258
   --  temp files at the same time in the same directory.
259
 
260
   procedure Create_Temp_Output_File
261
     (FD   : out File_Descriptor;
262
      Name : out String_Access);
263
   --  Create and open for writing a temporary file in the current working
264
   --  directory suitable to redirect standard output. The name of the file and
265
   --  the File Descriptor are returned. It is the responsibility of the caller
266
   --  to deallocate the access value returned in Name.
267
   --
268
   --  The file is opened in text mode
269
   --
270
   --  This procedure will always succeed if the current working directory is
271
   --  writable. If the current working directory is not writable, then
272
   --  Invalid_FD is returned for the file descriptor and null for the Name.
273
   --  There is no race condition problem between processes trying to create
274
   --  temp files at the same time in the same directory.
275
 
276
   procedure Close (FD : File_Descriptor; Status : out Boolean);
277
   --  Close file referenced by FD. Status is False if the underlying service
278
   --  failed. Reasons for failure include: disk full, disk quotas exceeded
279
   --  and invalid file descriptor (the file may have been closed twice).
280
 
281
   procedure Close (FD : File_Descriptor);
282
   --  Close file referenced by FD. This form is used when the caller wants to
283
   --  ignore any possible error (see above for error cases).
284
 
285
   procedure Set_Close_On_Exec
286
     (FD            : File_Descriptor;
287
      Close_On_Exec : Boolean;
288
      Status        : out Boolean);
289
   --  When Close_On_Exec is True, mark FD to be closed automatically when new
290
   --  program is executed by the calling process (i.e. prevent FD from being
291
   --  inherited by child processes). When Close_On_Exec is False, mark FD to
292
   --  not be closed on exec (i.e. allow it to be inherited). Status is False
293
   --  if the operation could not be performed.
294
 
295
   procedure Delete_File (Name : String; Success : out Boolean);
296
   --  Deletes file. Success is set True or False indicating if the delete is
297
   --  successful.
298
 
299
   procedure Rename_File
300
     (Old_Name : String;
301
      New_Name : String;
302
      Success  : out Boolean);
303
   --  Rename a file. Success is set True or False indicating if the rename is
304
   --  successful or not.
305
 
306
   --  The following defines the mode for the Copy_File procedure below. Note
307
   --  that "time stamps and other file attributes" in the descriptions below
308
   --  refers to the creation and last modification times, and also the file
309
   --  access (read/write/execute) status flags.
310
 
311
   type Copy_Mode is
312
     (Copy,
313
      --  Copy the file. It is an error if the target file already exists. The
314
      --  time stamps and other file attributes are preserved in the copy.
315
 
316
      Overwrite,
317
      --  If the target file exists, the file is replaced otherwise the file
318
      --  is just copied. The time stamps and other file attributes are
319
      --  preserved in the copy.
320
 
321
      Append);
322
      --  If the target file exists, the contents of the source file is
323
      --  appended at the end. Otherwise the source file is just copied. The
324
      --  time stamps and other file attributes are preserved if the
325
      --  destination file does not exist.
326
 
327
   type Attribute is
328
     (Time_Stamps,
329
      --  Copy time stamps from source file to target file. All other
330
      --  attributes are set to normal default values for file creation.
331
 
332
      Full,
333
      --  All attributes are copied from the source file to the target file.
334
      --  This includes the timestamps, and for example also includes
335
      --  read/write/execute attributes in Unix systems.
336
 
337
      None);
338
      --  No attributes are copied. All attributes including the time stamp
339
      --  values are set to normal default values for file creation.
340
 
341
   --  Note: The default is Time_Stamps, which corresponds to the normal
342
   --  default on Windows style systems. Full corresponds to the typical
343
   --  effect of "cp -p" on Unix systems, and None corresponds to the typical
344
   --  effect of "cp" on Unix systems.
345
 
346
   --  Note: Time_Stamps and Full are not supported on VMS and VxWorks 5
347
 
348
   procedure Copy_File
349
     (Name     : String;
350
      Pathname : String;
351
      Success  : out Boolean;
352
      Mode     : Copy_Mode := Copy;
353
      Preserve : Attribute := Time_Stamps);
354
   --  Copy a file. Name must designate a single file (no wild cards allowed).
355
   --  Pathname can be a filename or directory name. In the latter case Name
356
   --  is copied into the directory preserving the same file name. Mode
357
   --  defines the kind of copy, see above with the default being a normal
358
   --  copy in which the target file must not already exist. Success is set to
359
   --  True or False indicating if the copy is successful (depending on the
360
   --  specified Mode).
361
   --
362
   --  Note: this procedure is only supported to a very limited extent on VMS.
363
   --  The only supported mode is Overwrite, and the only supported value for
364
   --  Preserve is None, resulting in the default action which for Overwrite
365
   --  is to leave attributes unchanged. Furthermore, the copy only works for
366
   --  simple text files.
367
 
368
   procedure Copy_Time_Stamps (Source, Dest : String; Success : out Boolean);
369
   --  Copy Source file time stamps (last modification and last access time
370
   --  stamps) to Dest file. Source and Dest must be valid filenames,
371
   --  furthermore Dest must be writable. Success will be set to True if the
372
   --  operation was successful and False otherwise.
373
   --
374
   --  Note: this procedure is not supported on VMS and VxWorks 5. On these
375
   --  platforms, Success is always set to False.
376
 
377
   function Read
378
     (FD : File_Descriptor;
379
      A  : System.Address;
380
      N  : Integer) return Integer;
381
   --  Read N bytes to address A from file referenced by FD. Returned value is
382
   --  count of bytes actually read, which can be less than N at EOF.
383
 
384
   function Write
385
     (FD : File_Descriptor;
386
      A  : System.Address;
387
      N  : Integer) return Integer;
388
   --  Write N bytes from address A to file referenced by FD. The returned
389
   --  value is the number of bytes written, which can be less than N if a
390
   --  disk full condition was detected.
391
 
392
   Seek_Cur : constant := 1;
393
   Seek_End : constant := 2;
394
   Seek_Set : constant := 0;
395
   --  Used to indicate origin for Lseek call
396
 
397
   procedure Lseek
398
     (FD     : File_Descriptor;
399
      offset : Long_Integer;
400
      origin : Integer);
401
   pragma Import (C, Lseek, "__gnat_lseek");
402
   --  Sets the current file pointer to the indicated offset value, relative
403
   --  to the current position (origin = SEEK_CUR), end of file (origin =
404
   --  SEEK_END), or start of file (origin = SEEK_SET).
405
 
406
   function File_Length (FD : File_Descriptor) return Long_Integer;
407
   pragma Import (C, File_Length, "__gnat_file_length");
408
   --  Get length of file from file descriptor FD
409
 
410
   function File_Time_Stamp (Name : String) return OS_Time;
411
   --  Given the name of a file or directory, Name, obtains and returns the
412
   --  time stamp. This function can be used for an unopened file. Returns
413
   --  Invalid_Time is Name doesn't correspond to an existing file.
414
 
415
   function File_Time_Stamp (FD : File_Descriptor) return OS_Time;
416
   --  Get time stamp of file from file descriptor FD Returns Invalid_Time is
417
   --  FD doesn't correspond to an existing file.
418
 
419
   function Normalize_Pathname
420
     (Name           : String;
421
      Directory      : String  := "";
422
      Resolve_Links  : Boolean := True;
423
      Case_Sensitive : Boolean := True) return String;
424
   --  Returns a file name as an absolute path name, resolving all relative
425
   --  directories, and symbolic links. The parameter Directory is a fully
426
   --  resolved path name for a directory, or the empty string (the default).
427
   --  Name is the name of a file, which is either relative to the given
428
   --  directory name, if Directory is non-null, or to the current working
429
   --  directory if Directory is null. The result returned is the normalized
430
   --  name of the file. For most cases, if two file names designate the same
431
   --  file through different paths, Normalize_Pathname will return the same
432
   --  canonical name in both cases. However, there are cases when this is not
433
   --  true; for example, this is not true in Unix for two hard links
434
   --  designating the same file.
435
   --
436
   --  On Windows, the returned path will start with a drive letter except
437
   --  when Directory is not empty and does not include a drive letter. If
438
   --  Directory is empty (the default) and Name is a relative path or an
439
   --  absolute path without drive letter, the letter of the current drive
440
   --  will start the returned path. If Case_Sensitive is True (the default),
441
   --  then this drive letter will be forced to upper case ("C:\...").
442
   --
443
   --  If Resolve_Links is set to True, then the symbolic links, on systems
444
   --  that support them, will be fully converted to the name of the file or
445
   --  directory pointed to. This is slightly less efficient, since it
446
   --  requires system calls.
447
   --
448
   --  If Name cannot be resolved or is null on entry (for example if there is
449
   --  symbolic link circularity, e.g. A is a symbolic link for B, and B is a
450
   --  symbolic link for A), then Normalize_Pathname returns an empty  string.
451
   --
452
   --  In VMS, if Name follows the VMS syntax file specification, it is first
453
   --  converted into Unix syntax. If the conversion fails, Normalize_Pathname
454
   --  returns an empty string.
455
   --
456
   --  For case-sensitive file systems, the value of Case_Sensitive parameter
457
   --  is ignored. For file systems that are not case-sensitive, such as
458
   --  Windows and OpenVMS, if this parameter is set to False, then the file
459
   --  and directory names are folded to lower case. This allows checking
460
   --  whether two files are the same by applying this function to their names
461
   --  and comparing the results. If Case_Sensitive is set to True, this
462
   --  function does not change the casing of file and directory names.
463
 
464
   function Is_Absolute_Path (Name : String) return Boolean;
465
   --  Returns True if Name is an absolute path name, i.e. it designates a
466
   --  file or directory absolutely rather than relative to another directory.
467
 
468
   function Is_Regular_File (Name : String) return Boolean;
469
   --  Determines if the given string, Name, is the name of an existing
470
   --  regular file. Returns True if so, False otherwise. Name may be an
471
   --  absolute path name or a relative path name, including a simple file
472
   --  name. If it is a relative path name, it is relative to the current
473
   --  working directory.
474
 
475
   function Is_Directory (Name : String) return Boolean;
476
   --  Determines if the given string, Name, is the name of a directory.
477
   --  Returns True if so, False otherwise. Name may be an absolute path
478
   --  name or a relative path name, including a simple file name. If it is
479
   --  a relative path name, it is relative to the current working directory.
480
 
481
   function Is_Readable_File (Name : String) return Boolean;
482
   --  Determines if the given string, Name, is the name of an existing file
483
   --  that is readable. Returns True if so, False otherwise. Note that this
484
   --  function simply interrogates the file attributes (e.g. using the C
485
   --  function stat), so it does not indicate a situation in which a file may
486
   --  not actually be readable due to some other process having exclusive
487
   --  access.
488
 
489
   function Is_Executable_File (Name : String) return Boolean;
490
   --  Determines if the given string, Name, is the name of an existing file
491
   --  that is executable. Returns True if so, False otherwise. Note that this
492
   --  function simply interrogates the file attributes (e.g. using the C
493
   --  function stat), so it does not indicate a situation in which a file may
494
   --  not actually be readable due to some other process having exclusive
495
   --  access.
496
 
497
   function Is_Writable_File (Name : String) return Boolean;
498
   --  Determines if the given string, Name, is the name of an existing file
499
   --  that is writable. Returns True if so, False otherwise. Note that this
500
   --  function simply interrogates the file attributes (e.g. using the C
501
   --  function stat), so it does not indicate a situation in which a file may
502
   --  not actually be writeable due to some other process having exclusive
503
   --  access.
504
 
505
   function Is_Symbolic_Link (Name : String) return Boolean;
506
   --  Determines if the given string, Name, is the path of a symbolic link on
507
   --  systems that support it. Returns True if so, False if the path is not a
508
   --  symbolic link or if the system does not support symbolic links.
509
   --
510
   --  A symbolic link is an indirect pointer to a file; its directory entry
511
   --  contains the name of the file to which it is linked. Symbolic links may
512
   --  span file systems and may refer to directories.
513
 
514
   procedure Set_Writable (Name : String);
515
   --  Change permissions on the named file to make it writable for its owner
516
 
517
   procedure Set_Non_Writable (Name : String);
518
   --  Change permissions on the named file to make it non-writable for its
519
   --  owner. The readable and executable permissions are not modified.
520
 
521
   procedure Set_Read_Only (Name : String) renames Set_Non_Writable;
522
   --  This renaming is provided for backwards compatibility with previous
523
   --  versions. The use of Set_Non_Writable is preferred (clearer name).
524
 
525
   procedure Set_Executable (Name : String);
526
   --  Change permissions on the named file to make it executable for its owner
527
 
528
   procedure Set_Readable (Name : String);
529
   --  Change permissions on the named file to make it readable for its
530
   --  owner.
531
 
532
   procedure Set_Non_Readable (Name : String);
533
   --  Change permissions on the named file to make it non-readable for
534
   --  its owner. The writable and executable permissions are not
535
   --  modified.
536
 
537
   function Locate_Exec_On_Path
538
     (Exec_Name : String) return String_Access;
539
   --  Try to locate an executable whose name is given by Exec_Name in the
540
   --  directories listed in the environment Path. If the Exec_Name does not
541
   --  have the executable suffix, it will be appended before the search.
542
   --  Otherwise works like Locate_Regular_File below. If the executable is
543
   --  not found, null is returned.
544
   --
545
   --  Note that this function allocates memory for the returned value. This
546
   --  memory needs to be deallocated after use.
547
 
548
   function Locate_Regular_File
549
     (File_Name : String;
550
      Path      : String) return String_Access;
551
   --  Try to locate a regular file whose name is given by File_Name in the
552
   --  directories listed in Path. If a file is found, its full pathname is
553
   --  returned; otherwise, a null pointer is returned. If the File_Name given
554
   --  is an absolute pathname, then Locate_Regular_File just checks that the
555
   --  file exists and is a regular file. Otherwise, if the File_Name given
556
   --  includes directory information, Locate_Regular_File first checks if the
557
   --  file exists relative to the current directory. If it does not, or if
558
   --  the File_Name given is a simple file name, the Path argument is parsed
559
   --  according to OS conventions, and for each directory in the Path a check
560
   --  is made if File_Name is a relative pathname of a regular file from that
561
   --  directory.
562
   --
563
   --  Note that this function allocates some memory for the returned value.
564
   --  This memory needs to be deallocated after use.
565
 
566
   function Get_Debuggable_Suffix return String_Access;
567
   --  Return the debuggable suffix convention. Usually this is the same as
568
   --  the convention for Get_Executable_Suffix. The result is allocated on
569
   --  the heap and should be freed after use to avoid storage leaks.
570
 
571
   function Get_Target_Debuggable_Suffix return String_Access;
572
   --  Return the target debuggable suffix convention. Usually this is the same
573
   --  as the convention for Get_Executable_Suffix. The result is allocated on
574
   --  the heap and should be freed after use to avoid storage leaks.
575
 
576
   function Get_Executable_Suffix return String_Access;
577
   --  Return the executable suffix convention. The result is allocated on the
578
   --  heap and should be freed after use to avoid storage leaks.
579
 
580
   function Get_Object_Suffix return String_Access;
581
   --  Return the object suffix convention. The result is allocated on the heap
582
   --  and should be freed after use to avoid storage leaks.
583
 
584
   function Get_Target_Executable_Suffix return String_Access;
585
   --  Return the target executable suffix convention. The result is allocated
586
   --  on the heap and should be freed after use to avoid storage leaks.
587
 
588
   function Get_Target_Object_Suffix return String_Access;
589
   --  Return the target object suffix convention. The result is allocated on
590
   --  the heap and should be freed after use to avoid storage leaks.
591
 
592
   --  The following section contains low-level routines using addresses to
593
   --  pass file name and executable name. In each routine the name must be
594
   --  Nul-Terminated. For complete documentation refer to the equivalent
595
   --  routine (using String in place of C_File_Name) defined above.
596
 
597
   subtype C_File_Name is System.Address;
598
   --  This subtype is used to document that a parameter is the address of a
599
   --  null-terminated string containing the name of a file.
600
 
601
   --  All the following functions need comments ???
602
 
603
   function Open_Read
604
     (Name  : C_File_Name;
605
      Fmode : Mode) return File_Descriptor;
606
 
607
   function Open_Read_Write
608
     (Name  : C_File_Name;
609
      Fmode : Mode) return File_Descriptor;
610
 
611
   function Create_File
612
     (Name  : C_File_Name;
613
      Fmode : Mode) return File_Descriptor;
614
 
615
   function Create_New_File
616
     (Name  : C_File_Name;
617
      Fmode : Mode) return File_Descriptor;
618
 
619
   procedure Delete_File (Name : C_File_Name; Success : out Boolean);
620
 
621
   procedure Rename_File
622
     (Old_Name : C_File_Name;
623
      New_Name : C_File_Name;
624
      Success  : out Boolean);
625
 
626
   procedure Copy_File
627
     (Name     : C_File_Name;
628
      Pathname : C_File_Name;
629
      Success  : out Boolean;
630
      Mode     : Copy_Mode := Copy;
631
      Preserve : Attribute := Time_Stamps);
632
 
633
   procedure Copy_Time_Stamps
634
     (Source, Dest : C_File_Name;
635
      Success      : out Boolean);
636
 
637
   function File_Time_Stamp (Name : C_File_Name) return OS_Time;
638
   --  Returns Invalid_Time is Name doesn't correspond to an existing file
639
 
640
   function Is_Regular_File (Name : C_File_Name) return Boolean;
641
   function Is_Directory (Name : C_File_Name) return Boolean;
642
   function Is_Readable_File (Name : C_File_Name) return Boolean;
643
   function Is_Executable_File (Name : C_File_Name) return Boolean;
644
   function Is_Writable_File (Name : C_File_Name) return Boolean;
645
   function Is_Symbolic_Link (Name : C_File_Name) return Boolean;
646
 
647
   function Locate_Regular_File
648
     (File_Name : C_File_Name;
649
      Path      : C_File_Name) return String_Access;
650
 
651
   ------------------
652
   -- Subprocesses --
653
   ------------------
654
 
655
   subtype Argument_List is String_List;
656
   --  Type used for argument list in call to Spawn. The lower bound of the
657
   --  array should be 1, and the length of the array indicates the number of
658
   --  arguments.
659
 
660
   subtype Argument_List_Access is String_List_Access;
661
   --  Type used to return Argument_List without dragging in secondary stack.
662
   --  Note that there is a Free procedure declared for this subtype which
663
   --  frees the array and all referenced strings.
664
 
665
   procedure Normalize_Arguments (Args : in out Argument_List);
666
   --  Normalize all arguments in the list. This ensure that the argument list
667
   --  is compatible with the running OS and will works fine with Spawn and
668
   --  Non_Blocking_Spawn for example. If Normalize_Arguments is called twice
669
   --  on the same list it will do nothing the second time. Note that Spawn
670
   --  and Non_Blocking_Spawn call Normalize_Arguments automatically, but
671
   --  since there is a guarantee that a second call does nothing, this
672
   --  internal call will have no effect if Normalize_Arguments is called
673
   --  before calling Spawn. The call to Normalize_Arguments assumes that the
674
   --  individual referenced arguments in Argument_List are on the heap, and
675
   --  may free them and reallocate if they are modified.
676
 
677
   procedure Spawn
678
     (Program_Name : String;
679
      Args         : Argument_List;
680
      Success      : out Boolean);
681
   --  This procedure spawns a program with a given list of arguments. The
682
   --  first parameter of is the name of the executable. The second parameter
683
   --  contains the arguments to be passed to this program. Success is False
684
   --  if the named program could not be spawned or its execution completed
685
   --  unsuccessfully. Note that the caller will be blocked until the
686
   --  execution of the spawned program is complete. For maximum portability,
687
   --  use a full path name for the Program_Name argument. On some systems
688
   --  (notably Unix systems) a simple file name may also work (if the
689
   --  executable can be located in the path).
690
   --
691
   --  Spawning processes from tasking programs is not recommended. See
692
   --  "NOTE: Spawn in tasking programs" below.
693
   --
694
   --  Note: Arguments in Args that contain spaces and/or quotes such as
695
   --  "--GCC=gcc -v" or "--GCC=""gcc -v""" are not portable across all
696
   --  operating systems, and would not have the desired effect if they were
697
   --  passed directly to the operating system. To avoid this problem, Spawn
698
   --  makes an internal call to Normalize_Arguments, which ensures that such
699
   --  arguments are modified in a manner that ensures that the desired effect
700
   --  is obtained on all operating systems. The caller may call
701
   --  Normalize_Arguments explicitly before the call (e.g. to print out the
702
   --  exact form of arguments passed to the operating system). In this case
703
   --  the guarantee a second call to Normalize_Arguments has no effect
704
   --  ensures that the internal call will not affect the result. Note that
705
   --  the implicit call to Normalize_Arguments may free and reallocate some
706
   --  of the individual arguments.
707
   --
708
   --  This function will always set Success to False under VxWorks and other
709
   --  similar operating systems which have no notion of the concept of
710
   --  dynamically executable file. Otherwise Success is set True if the exit
711
   --  status of the spawned process is zero.
712
 
713
   function Spawn
714
     (Program_Name : String;
715
      Args         : Argument_List) return Integer;
716
   --  Similar to the above procedure, but returns the actual status returned
717
   --  by the operating system, or -1 under VxWorks and any other similar
718
   --  operating systems which have no notion of separately spawnable programs.
719
   --
720
   --  Spawning processes from tasking programs is not recommended. See
721
   --  "NOTE: Spawn in tasking programs" below.
722
 
723
   procedure Spawn
724
     (Program_Name           : String;
725
      Args                   : Argument_List;
726
      Output_File_Descriptor : File_Descriptor;
727
      Return_Code            : out Integer;
728
      Err_To_Out             : Boolean := True);
729
   --  Similar to the procedure above, but redirects the output to the file
730
   --  designated by Output_File_Descriptor. If Err_To_Out is True, then the
731
   --  Standard Error output is also redirected.
732
   --  Return_Code is set to the status code returned by the operating system
733
   --
734
   --  Spawning processes from tasking programs is not recommended. See
735
   --  "NOTE: Spawn in tasking programs" below.
736
 
737
   procedure Spawn
738
     (Program_Name : String;
739
      Args         : Argument_List;
740
      Output_File  : String;
741
      Success      : out Boolean;
742
      Return_Code  : out Integer;
743
      Err_To_Out   : Boolean := True);
744
   --  Similar to the procedure above, but saves the output of the command to
745
   --  a file with the name Output_File.
746
   --
747
   --  Success is set to True if the command is executed and its output
748
   --  successfully written to the file. If Success is True, then Return_Code
749
   --  will be set to the status code returned by the operating system.
750
   --  Otherwise, Return_Code is undefined.
751
   --
752
   --  Spawning processes from tasking programs is not recommended. See
753
   --  "NOTE: Spawn in tasking programs" below.
754
 
755
   type Process_Id is private;
756
   --  A private type used to identify a process activated by the following
757
   --  non-blocking calls. The only meaningful operation on this type is a
758
   --  comparison for equality.
759
 
760
   Invalid_Pid : constant Process_Id;
761
   --  A special value used to indicate errors, as described below
762
 
763
   function Pid_To_Integer (Pid : Process_Id) return Integer;
764
   --  Convert a process id to an Integer. Useful for writing hash functions
765
   --  for type Process_Id or to compare two Process_Id (e.g. for sorting).
766
 
767
   function Non_Blocking_Spawn
768
     (Program_Name : String;
769
      Args         : Argument_List) return Process_Id;
770
   --  This is a non blocking call. The Process_Id of the spawned process is
771
   --  returned. Parameters are to be used as in Spawn. If Invalid_Pid is
772
   --  returned the program could not be spawned.
773
   --
774
   --  Spawning processes from tasking programs is not recommended. See
775
   --  "NOTE: Spawn in tasking programs" below.
776
   --
777
   --  This function will always return Invalid_Pid under VxWorks, since there
778
   --  is no notion of executables under this OS.
779
 
780
   function Non_Blocking_Spawn
781
     (Program_Name           : String;
782
      Args                   : Argument_List;
783
      Output_File_Descriptor : File_Descriptor;
784
      Err_To_Out             : Boolean := True) return Process_Id;
785
   --  Similar to the procedure above, but redirects the output to the file
786
   --  designated by Output_File_Descriptor. If Err_To_Out is True, then the
787
   --  Standard Error output is also redirected. Invalid_Pid is returned
788
   --  if the program could not be spawned successfully.
789
   --
790
   --  Spawning processes from tasking programs is not recommended. See
791
   --  "NOTE: Spawn in tasking programs" below.
792
   --
793
   --  This function will always return Invalid_Pid under VxWorks, since there
794
   --  is no notion of executables under this OS.
795
 
796
   function Non_Blocking_Spawn
797
     (Program_Name : String;
798
      Args         : Argument_List;
799
      Output_File  : String;
800
      Err_To_Out   : Boolean := True) return Process_Id;
801
   --  Similar to the procedure above, but saves the output of the command to
802
   --  a file with the name Output_File.
803
   --
804
   --  Success is set to True if the command is executed and its output
805
   --  successfully written to the file. Invalid_Pid is returned if the output
806
   --  file could not be created or if the program could not be spawned
807
   --  successfully.
808
   --
809
   --  Spawning processes from tasking programs is not recommended. See
810
   --  "NOTE: Spawn in tasking programs" below.
811
   --
812
   --  This function will always return Invalid_Pid under VxWorks, since there
813
   --  is no notion of executables under this OS.
814
 
815
   procedure Wait_Process (Pid : out Process_Id; Success : out Boolean);
816
   --  Wait for the completion of any of the processes created by previous
817
   --  calls to Non_Blocking_Spawn. The caller will be suspended until one of
818
   --  these processes terminates (normally or abnormally). If any of these
819
   --  subprocesses terminates prior to the call to Wait_Process (and has not
820
   --  been returned by a previous call to Wait_Process), then the call to
821
   --  Wait_Process is immediate. Pid identifies the process that has
822
   --  terminated (matching the value returned from Non_Blocking_Spawn).
823
   --  Success is set to True if this sub-process terminated successfully. If
824
   --  Pid = Invalid_Pid, there were no subprocesses left to wait on.
825
   --
826
   --  This function will always set success to False under VxWorks, since
827
   --  there is no notion of executables under this OS.
828
 
829
   function Argument_String_To_List
830
     (Arg_String : String) return Argument_List_Access;
831
   --  Take a string that is a program and its arguments and parse it into an
832
   --  Argument_List. Note that the result is allocated on the heap, and must
833
   --  be freed by the programmer (when it is no longer needed) to avoid
834
   --  memory leaks.
835
 
836
   -------------------------------------
837
   -- NOTE: Spawn in Tasking Programs --
838
   -------------------------------------
839
 
840
   --  Spawning processes in tasking programs using the above Spawn and
841
   --  Non_Blocking_Spawn subprograms is not recommended, because there are
842
   --  subtle interactions between creating a process and signals/locks that
843
   --  can cause trouble. These issues are not specific to Ada; they depend
844
   --  primarily on the operating system.
845
 
846
   --  If you need to spawn processes in a tasking program, you will need to
847
   --  understand the semantics of your operating system, and you are likely to
848
   --  write non-portable code, because operating systems differ in this area.
849
 
850
   --  The Spawn and Non_Blocking_Spawn subprograms call the following
851
   --  operating system functions:
852
 
853
   --     On Windows: spawnvp (blocking) or CreateProcess (non-blocking)
854
 
855
   --     On Solaris: fork1, followed in the child process by execv
856
 
857
   --     On other Unix-like systems, and on VMS: fork, followed in the child
858
   --     process by execv.
859
 
860
   --     On vxworks, nucleus, and RTX, spawning of processes is not supported
861
 
862
   --  For details, look at the functions __gnat_portable_spawn and
863
   --  __gnat_portable_no_block_spawn in adaint.c.
864
 
865
   --  You should read the operating-system-specific documentation for the
866
   --  above functions, paying special attention to subtle interactions with
867
   --  threading, signals, locks, and file descriptors. Most of the issues are
868
   --  related to the fact that on Unix, there is a window of time between fork
869
   --  and execv; Windows does not have this problem, because spawning is done
870
   --  in a single operation.
871
 
872
   --  On Posix-compliant systems, such as Linux, fork duplicates just the
873
   --  calling thread. (On Solaris, fork1 is the Posix-compliant version of
874
   --  fork.)
875
 
876
   --  You should avoid using signals while spawning. This includes signals
877
   --  used internally by the Ada run-time system, such as timer signals used
878
   --  to implement delay statements.
879
 
880
   --  It is best to spawn any subprocesses very early, before the parent
881
   --  process creates tasks, locks, or installs signal handlers. Certainly
882
   --  avoid doing simultaneous spawns from multiple threads of the same
883
   --  process.
884
 
885
   --  There is no problem spawning a subprocess that uses tasking: the
886
   --  problems are caused only by tasking in the parent.
887
 
888
   --  If the parent is using tasking, and needs to spawn subprocesses at
889
   --  arbitrary times, one technique is for the parent to spawn (very early)
890
   --  a particular spawn-manager subprocess whose job is to spawn other
891
   --  processes. The spawn-manager must avoid tasking. The parent sends
892
   --  messages to the spawn-manager requesting it to spawn processes, using
893
   --  whatever inter-process communication mechanism you like, such as
894
   --  sockets.
895
 
896
   --  In short, mixing spawning of subprocesses with tasking is a tricky
897
   --  business, and should be avoided if possible, but if it is necessary,
898
   --  the above guidelines should be followed, and you should beware of
899
   --  portability problems.
900
 
901
   -------------------
902
   -- Miscellaneous --
903
   -------------------
904
 
905
   function Getenv (Name : String) return String_Access;
906
   --  Get the value of the environment variable. Returns an access to the
907
   --  empty string if the environment variable does not exist or has an
908
   --  explicit null value (in some operating systems these are distinct
909
   --  cases, in others they are not; this interface abstracts away that
910
   --  difference. The argument is allocated on the heap (even in the null
911
   --  case), and needs to be freed explicitly when no longer needed to avoid
912
   --  memory leaks.
913
 
914
   procedure Setenv (Name : String; Value : String);
915
   --  Set the value of the environment variable Name to Value. This call
916
   --  modifies the current environment, but does not modify the parent
917
   --  process environment. After a call to Setenv, Getenv (Name) will always
918
   --  return a String_Access referencing the same String as Value. This is
919
   --  true also for the null string case (the actual effect may be to either
920
   --  set an explicit null as the value, or to remove the entry, this is
921
   --  operating system dependent). Note that any following calls to Spawn
922
   --  will pass an environment to the spawned process that includes the
923
   --  changes made by Setenv calls. This procedure is not available on VMS.
924
 
925
   procedure OS_Exit (Status : Integer);
926
   pragma No_Return (OS_Exit);
927
 
928
   --  Exit to OS with given status code (program is terminated). Note that
929
   --  this is abrupt termination. All tasks are immediately terminated. There
930
   --  are no finalization or other Ada-specific cleanup actions performed. On
931
   --  systems with atexit handlers (such as Unix and Windows), atexit handlers
932
   --  are called.
933
 
934
   type OS_Exit_Subprogram is access procedure (Status : Integer);
935
 
936
   procedure OS_Exit_Default (Status : Integer);
937
   pragma No_Return (OS_Exit_Default);
938
   --  Default implementation of procedure OS_Exit
939
 
940
   OS_Exit_Ptr : OS_Exit_Subprogram := OS_Exit_Default'Access;
941
   --  OS_Exit is implemented through this access value. It it then possible to
942
   --  change the implementation of OS_Exit by redirecting OS_Exit_Ptr to an
943
   --  other implementation.
944
 
945
   procedure OS_Abort;
946
   pragma Import (C, OS_Abort, "abort");
947
   pragma No_Return (OS_Abort);
948
   --  Exit to OS signalling an abort (traceback or other appropriate
949
   --  diagnostic information should be given if possible, or entry made to
950
   --  the debugger if that is possible).
951
 
952
   function Errno return Integer;
953
   pragma Import (C, Errno, "__get_errno");
954
   --  Return the task-safe last error number
955
 
956
   procedure Set_Errno (Errno : Integer);
957
   pragma Import (C, Set_Errno, "__set_errno");
958
   --  Set the task-safe error number
959
 
960
   Directory_Separator : constant Character;
961
   --  The character that is used to separate parts of a pathname
962
 
963
   Path_Separator : constant Character;
964
   --  The character to separate paths in an environment variable value
965
 
966
private
967
   pragma Import (C, Path_Separator, "__gnat_path_separator");
968
   pragma Import (C, Directory_Separator, "__gnat_dir_separator");
969
   pragma Import (C, Current_Time, "__gnat_current_time");
970
 
971
   type OS_Time is
972
     range -(2 ** (Standard'Address_Size - Integer'(1))) ..
973
           +(2 ** (Standard'Address_Size - Integer'(1)) - 1);
974
   --  Type used for timestamps in the compiler. This type is used to hold
975
   --  time stamps, but may have a different representation than C's time_t.
976
   --  This type needs to match the declaration of OS_Time in adaint.h.
977
 
978
   --  Add pragma Inline statements for comparison operations on OS_Time. It
979
   --  would actually be nice to use pragma Import (Intrinsic) here, but this
980
   --  was not properly supported till GNAT 3.15a, so that would cause
981
   --  bootstrap path problems. To be changed later ???
982
 
983
   Invalid_Time : constant OS_Time := -1;
984
   --  This value should match the return value from __gnat_file_time_*
985
 
986
   pragma Inline ("<");
987
   pragma Inline (">");
988
   pragma Inline ("<=");
989
   pragma Inline (">=");
990
 
991
   type Process_Id is new Integer;
992
   Invalid_Pid : constant Process_Id := -1;
993
 
994
end System.OS_Lib;

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