File : s-os_lib.ads
1 ------------------------------------------------------------------------------
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) 1995-2015, 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 -- --
19 -- --
20 -- --
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_Warning;
52
53 with System;
54 with System.Strings;
55
56 package System.OS_Lib is
57 pragma Preelaborate;
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 : String_Access; 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 : String_List; 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 "="
91 (Left : String_List_Access;
92 Right : String_List_Access) return Boolean renames Strings."=";
93
94 procedure Free (Arg : in out String_List_Access) 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. This
102 -- is the type returned by the File_Time_Stamp functions to obtain the time
103 -- stamp of a specified file. Functions and a procedure (modeled after the
104 -- similar subprograms in package Calendar) are provided for extracting
105 -- information from a value of this type. Although these are called GM, the
106 -- intention in the case of time stamps is not that they provide GMT times
107 -- in all cases but rather the actual (time-zone independent) time stamp of
108 -- the 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 function "<" (X : OS_Time; Y : OS_Time) return Boolean;
114 function ">" (X : OS_Time; Y : OS_Time) return Boolean;
115 function ">=" (X : OS_Time; Y : OS_Time) return Boolean;
116 function "<=" (X : OS_Time; Y : OS_Time) return Boolean;
117 -- Basic comparison operators on OS_Time with obvious meanings. Note that
118 -- these have Intrinsic convention, so for example it is not permissible
119 -- to create accesses to any of these functions.
120
121 subtype Year_Type is Integer range 1900 .. 2099;
122 subtype Month_Type is Integer range 1 .. 12;
123 subtype Day_Type is Integer range 1 .. 31;
124 subtype Hour_Type is Integer range 0 .. 23;
125 subtype Minute_Type is Integer range 0 .. 59;
126 subtype Second_Type is Integer range 0 .. 59;
127 -- Declarations similar to those in Calendar, breaking down the time
128
129 function Current_Time return OS_Time;
130 -- Return the system clock value as OS_Time
131
132 function Current_Time_String return String;
133 -- Returns current local time in the form YYYY-MM-DD HH:MM:SS. The result
134 -- has bounds 1 .. 19.
135
136 function GM_Year (Date : OS_Time) return Year_Type;
137 function GM_Month (Date : OS_Time) return Month_Type;
138 function GM_Day (Date : OS_Time) return Day_Type;
139 function GM_Hour (Date : OS_Time) return Hour_Type;
140 function GM_Minute (Date : OS_Time) return Minute_Type;
141 function GM_Second (Date : OS_Time) return Second_Type;
142 -- Functions to extract information from OS_Time value in GMT form
143
144 procedure GM_Split
145 (Date : OS_Time;
146 Year : out Year_Type;
147 Month : out Month_Type;
148 Day : out Day_Type;
149 Hour : out Hour_Type;
150 Minute : out Minute_Type;
151 Second : out Second_Type);
152 -- Analogous to the Split routine in Ada.Calendar, takes an OS_Time and
153 -- provides a representation of it as a set of component parts, to be
154 -- interpreted as a date point in UTC.
155
156 function GM_Time_Of
157 (Year : Year_Type;
158 Month : Month_Type;
159 Day : Day_Type;
160 Hour : Hour_Type;
161 Minute : Minute_Type;
162 Second : Second_Type) return OS_Time;
163 -- Analogous to the Time_Of routine in Ada.Calendar, takes a set of time
164 -- component parts to be interpreted in the local time zone, and returns
165 -- an OS_Time. Returns Invalid_Time if the creation fails.
166
167 ----------------
168 -- File Stuff --
169 ----------------
170
171 -- These routines give access to the open/creat/close/read/write level of
172 -- I/O routines in the typical C library (these functions are not part of
173 -- the ANSI C standard, but are typically available in all systems). See
174 -- also package Interfaces.C_Streams for access to the stream level
175 -- routines.
176
177 -- Note on file names. If a file name is passed as type String in any of
178 -- the following specifications, then the name is a normal Ada string and
179 -- need not be NUL-terminated. However, a trailing NUL character is
180 -- permitted, and will be ignored (more accurately, the NUL and any
181 -- characters that follow it will be ignored).
182
183 type File_Descriptor is new Integer;
184 -- Corresponds to the int file handle values used in the C routines
185
186 Standin : constant File_Descriptor := 0;
187 Standout : constant File_Descriptor := 1;
188 Standerr : constant File_Descriptor := 2;
189 -- File descriptors for standard input output files
190
191 Invalid_FD : constant File_Descriptor := -1;
192 -- File descriptor returned when error in opening/creating file
193
194 procedure Close (FD : File_Descriptor; Status : out Boolean);
195 -- Close file referenced by FD. Status is False if the underlying service
196 -- failed. Reasons for failure include: disk full, disk quotas exceeded
197 -- and invalid file descriptor (the file may have been closed twice).
198
199 procedure Close (FD : File_Descriptor);
200 -- Close file referenced by FD. This form is used when the caller wants to
201 -- ignore any possible error (see above for error cases).
202
203 type Copy_Mode is
204 (Copy,
205 -- Copy the file. It is an error if the target file already exists. The
206 -- time stamps and other file attributes are preserved in the copy.
207
208 Overwrite,
209 -- If the target file exists, the file is replaced otherwise the file
210 -- is just copied. The time stamps and other file attributes are
211 -- preserved in the copy.
212
213 Append);
214 -- If the target file exists, the contents of the source file is
215 -- appended at the end. Otherwise the source file is just copied. The
216 -- time stamps and other file attributes are preserved if the
217 -- destination file does not exist.
218
219 type Attribute is
220 (Time_Stamps,
221 -- Copy time stamps from source file to target file. All other
222 -- attributes are set to normal default values for file creation.
223
224 Full,
225 -- All attributes are copied from the source file to the target file.
226 -- This includes the timestamps, and for example also includes
227 -- read/write/execute attributes in Unix systems.
228
229 None);
230 -- No attributes are copied. All attributes including the time stamp
231 -- values are set to normal default values for file creation.
232
233 -- Note: The default is Time_Stamps, which corresponds to the normal
234 -- default on Windows style systems. Full corresponds to the typical
235 -- effect of "cp -p" on Unix systems, and None corresponds to the typical
236 -- effect of "cp" on Unix systems.
237
238 -- Note: Time_Stamps and Full are not supported on VxWorks 5
239
240 procedure Copy_File
241 (Name : String;
242 Pathname : String;
243 Success : out Boolean;
244 Mode : Copy_Mode := Copy;
245 Preserve : Attribute := Time_Stamps);
246 -- Copy a file. Name must designate a single file (no wild cards allowed).
247 -- Pathname can be a filename or directory name. In the latter case Name
248 -- is copied into the directory preserving the same file name. Mode
249 -- defines the kind of copy, see above with the default being a normal
250 -- copy in which the target file must not already exist. Success is set to
251 -- True or False indicating if the copy is successful (depending on the
252 -- specified Mode).
253
254 procedure Copy_File_Attributes
255 (From : String;
256 To : String;
257 Success : out Boolean;
258 Copy_Timestamp : Boolean := True;
259 Copy_Permissions : Boolean := True);
260 -- Copy some of the file attributes from one file to another. Both files
261 -- must exist, or Success is set to False.
262
263 procedure Copy_Time_Stamps
264 (Source : String;
265 Dest : String;
266 Success : out Boolean);
267 -- Copy Source file time stamps (last modification and last access time
268 -- stamps) to Dest file. Source and Dest must be valid filenames,
269 -- furthermore Dest must be writable. Success will be set to True if the
270 -- operation was successful and False otherwise.
271 --
272 -- Note: this procedure is not supported on VxWorks 5. On this platform,
273 -- Success is always set to False.
274
275 type Mode is (Binary, Text);
276 for Mode'Size use Integer'Size;
277 for Mode use (Binary => 0, Text => 1);
278 -- Used in all the Open and Create calls to specify if the file is to be
279 -- opened in binary mode or text mode. In systems like Unix, this has no
280 -- effect, but in systems capable of text mode translation, the use of
281 -- Text as the mode parameter causes the system to do CR/LF translation
282 -- and also to recognize the DOS end of file character on input. The use
283 -- of Text where appropriate allows programs to take a portable Unix view
284 -- of DOS-format files and process them appropriately.
285
286 function Create_File
287 (Name : String;
288 Fmode : Mode) return File_Descriptor;
289 -- Creates new file with given name for writing, returning file descriptor
290 -- for subsequent use in Write calls. If the file already exists, it is
291 -- overwritten. File descriptor returned is Invalid_FD if file cannot be
292 -- successfully created.
293
294 function Create_New_File
295 (Name : String;
296 Fmode : Mode) return File_Descriptor;
297 -- Create new file with given name for writing, returning file descriptor
298 -- for subsequent use in Write calls. This differs from Create_File in
299 -- that it fails if the file already exists. File descriptor returned is
300 -- Invalid_FD if the file exists or cannot be created.
301
302 function Create_Output_Text_File (Name : String) return File_Descriptor;
303 -- Creates new text file with given name suitable to redirect standard
304 -- output, returning file descriptor. File descriptor returned is
305 -- Invalid_FD if file cannot be successfully created.
306
307 Temp_File_Len : constant Integer := 12;
308 -- Length of name returned by Create_Temp_File call (GNAT-XXXXXX & NUL)
309
310 subtype Temp_File_Name is String (1 .. Temp_File_Len);
311 -- String subtype set by Create_Temp_File
312
313 procedure Create_Temp_File
314 (FD : out File_Descriptor;
315 Name : out Temp_File_Name);
316 -- Create and open for writing a temporary file in the current working
317 -- directory. The name of the file and the File Descriptor are returned.
318 -- The File Descriptor returned is Invalid_FD in the case of failure. No
319 -- mode parameter is provided. Since this is a temporary file, there is no
320 -- point in doing text translation on it.
321 --
322 -- On some operating systems, the maximum number of temp files that can be
323 -- created with this procedure may be limited. When the maximum is reached,
324 -- this procedure returns Invalid_FD. On some operating systems, there may
325 -- be a race condition between processes trying to create temp files at the
326 -- same time in the same directory using this procedure.
327
328 procedure Create_Temp_File
329 (FD : out File_Descriptor;
330 Name : out String_Access);
331 -- Create and open for writing a temporary file in the current working
332 -- directory. The name of the file and the File Descriptor are returned.
333 -- It is the responsibility of the caller to deallocate the access value
334 -- returned in Name.
335 --
336 -- The file is opened in binary mode (no text translation).
337 --
338 -- This procedure will always succeed if the current working directory is
339 -- writable. If the current working directory is not writable, then
340 -- Invalid_FD is returned for the file descriptor and null for the Name.
341 -- There is no race condition problem between processes trying to create
342 -- temp files at the same time in the same directory.
343
344 procedure Create_Temp_Output_File
345 (FD : out File_Descriptor;
346 Name : out String_Access);
347 -- Create and open for writing a temporary file in the current working
348 -- directory suitable to redirect standard output. The name of the file and
349 -- the File Descriptor are returned. It is the responsibility of the caller
350 -- to deallocate the access value returned in Name.
351 --
352 -- The file is opened in text mode
353 --
354 -- This procedure will always succeed if the current working directory is
355 -- writable. If the current working directory is not writable, then
356 -- Invalid_FD is returned for the file descriptor and null for the Name.
357 -- There is no race condition problem between processes trying to create
358 -- temp files at the same time in the same directory.
359
360 procedure Delete_File (Name : String; Success : out Boolean);
361 -- Deletes file. Success is set True or False indicating if the delete is
362 -- successful.
363
364 function File_Length (FD : File_Descriptor) return Long_Integer;
365 pragma Import (C, File_Length, "__gnat_file_length_long");
366
367 type Large_File_Size is range -2**63 .. 2**63 - 1;
368 -- Maximum supported size for a file (8 exabytes = 8 million terabytes,
369 -- should be enough to accomodate all possible needs for quite a while).
370
371 function File_Length64 (FD : File_Descriptor) return Large_File_Size;
372 pragma Import (C, File_Length64, "__gnat_file_length");
373 -- Get length of file from file descriptor FD
374
375 function File_Time_Stamp (Name : String) return OS_Time;
376 -- Given the name of a file or directory, Name, obtains and returns the
377 -- time stamp. This function can be used for an unopened file. Returns
378 -- Invalid_Time is Name doesn't correspond to an existing file.
379
380 function File_Time_Stamp (FD : File_Descriptor) return OS_Time;
381 -- Get time stamp of file from file descriptor FD Returns Invalid_Time is
382 -- FD doesn't correspond to an existing file.
383
384 function Get_Debuggable_Suffix return String_Access;
385 -- Return the debuggable suffix convention. Usually this is the same as
386 -- the convention for Get_Executable_Suffix. The result is allocated on
387 -- the heap and should be freed after use to avoid storage leaks.
388
389 function Get_Executable_Suffix return String_Access;
390 -- Return the executable suffix convention. The result is allocated on the
391 -- heap and should be freed after use to avoid storage leaks.
392
393 function Get_Object_Suffix return String_Access;
394 -- Return the object suffix convention. The result is allocated on the heap
395 -- and should be freed after use to avoid storage leaks.
396
397 function Get_Target_Debuggable_Suffix return String_Access;
398 -- Return the target debuggable suffix convention. Usually this is the same
399 -- as the convention for Get_Executable_Suffix. The result is allocated on
400 -- the heap and should be freed after use to avoid storage leaks.
401
402 function Get_Target_Executable_Suffix return String_Access;
403 -- Return the target executable suffix convention. The result is allocated
404 -- on the heap and should be freed after use to avoid storage leaks.
405
406 function Get_Target_Object_Suffix return String_Access;
407 -- Return the target object suffix convention. The result is allocated on
408 -- the heap and should be freed after use to avoid storage leaks.
409
410 function Is_Absolute_Path (Name : String) return Boolean;
411 -- Returns True if Name is an absolute path name, i.e. it designates a
412 -- file or directory absolutely rather than relative to another directory.
413
414 function Is_Directory (Name : String) return Boolean;
415 -- Determines if the given string, Name, is the name of a directory.
416 -- Returns True if so, False otherwise. Name may be an absolute path
417 -- name or a relative path name, including a simple file name. If it is
418 -- a relative path name, it is relative to the current working directory.
419
420 function Is_Executable_File (Name : String) return Boolean;
421 -- Determines if the given string, Name, is the name of an existing file
422 -- that is executable. Returns True if so, False otherwise. Note that this
423 -- function simply interrogates the file attributes (e.g. using the C
424 -- function stat), so it does not indicate a situation in which a file may
425 -- not actually be readable due to some other process having exclusive
426 -- access.
427
428 function Is_Readable_File (Name : String) return Boolean;
429 -- Determines if the given string, Name, is the name of an existing file
430 -- that is readable. Returns True if so, False otherwise. Note that this
431 -- function simply interrogates the file attributes (e.g. using the C
432 -- function stat), so it does not indicate a situation in which a file may
433 -- not actually be readable due to some other process having exclusive
434 -- access.
435
436 function Is_Regular_File (Name : String) return Boolean;
437 -- Determines if the given string, Name, is the name of an existing
438 -- regular file. Returns True if so, False otherwise. Name may be an
439 -- absolute path name or a relative path name, including a simple file
440 -- name. If it is a relative path name, it is relative to the current
441 -- working directory.
442
443 function Is_Symbolic_Link (Name : String) return Boolean;
444 -- Determines if the given string, Name, is the path of a symbolic link on
445 -- systems that support it. Returns True if so, False if the path is not a
446 -- symbolic link or if the system does not support symbolic links.
447 --
448 -- A symbolic link is an indirect pointer to a file; its directory entry
449 -- contains the name of the file to which it is linked. Symbolic links may
450 -- span file systems and may refer to directories.
451
452 function Is_Writable_File (Name : String) return Boolean;
453 -- Determines if the given string, Name, is the name of an existing file
454 -- that is writable. Returns True if so, False otherwise. Note that this
455 -- function simply interrogates the file attributes (e.g. using the C
456 -- function stat), so it does not indicate a situation in which a file may
457 -- not actually be writable due to some other process having exclusive
458 -- access.
459
460 function Locate_Exec_On_Path (Exec_Name : String) return String_Access;
461 -- Try to locate an executable whose name is given by Exec_Name in the
462 -- directories listed in the environment Path. If the Exec_Name does not
463 -- have the executable suffix, it will be appended before the search.
464 -- Otherwise works like Locate_Regular_File below. If the executable is
465 -- not found, null is returned.
466 --
467 -- Note that this function allocates memory for the returned value. This
468 -- memory needs to be deallocated after use.
469
470 function Locate_Regular_File
471 (File_Name : String;
472 Path : String) return String_Access;
473 -- Try to locate a regular file whose name is given by File_Name in the
474 -- directories listed in Path. If a file is found, its full pathname is
475 -- returned; otherwise, a null pointer is returned. If the File_Name given
476 -- is an absolute pathname, then Locate_Regular_File just checks that the
477 -- file exists and is a regular file. Otherwise, if the File_Name given
478 -- includes directory information, Locate_Regular_File first checks if the
479 -- file exists relative to the current directory. If it does not, or if
480 -- the File_Name given is a simple file name, the Path argument is parsed
481 -- according to OS conventions, and for each directory in the Path a check
482 -- is made if File_Name is a relative pathname of a regular file from that
483 -- directory.
484 --
485 -- Note that this function allocates some memory for the returned value.
486 -- This memory needs to be deallocated after use.
487
488 Seek_Cur : constant := 1;
489 Seek_End : constant := 2;
490 Seek_Set : constant := 0;
491 -- Used to indicate origin for Lseek call
492
493 procedure Lseek
494 (FD : File_Descriptor;
495 offset : Long_Integer;
496 origin : Integer);
497 pragma Import (C, Lseek, "__gnat_lseek");
498 -- Sets the current file pointer to the indicated offset value, relative
499 -- to the current position (origin = SEEK_CUR), end of file (origin =
500 -- SEEK_END), or start of file (origin = SEEK_SET).
501
502 function Normalize_Pathname
503 (Name : String;
504 Directory : String := "";
505 Resolve_Links : Boolean := True;
506 Case_Sensitive : Boolean := True) return String;
507 -- Returns a file name as an absolute path name, resolving all relative
508 -- directories, and symbolic links. If Name is a relative path, it is
509 -- interpreted relative to Directory, or to the current directory if
510 -- Directory is the empty string (the default). The result returned is
511 -- the normalized name of the file, containing no "." or ".." components,
512 -- and no duplicated directory separators. For most cases, if two file
513 -- names designate the same file through different paths,
514 -- Normalize_Pathname will return the same canonical name in both cases.
515 -- However, there are cases when this is not true; for example, this is
516 -- not true in Unix for two hard links designating the same file.
517 --
518 -- On Windows, the returned path will start with a drive letter. If
519 -- Directory is empty (the default) and Name is a relative path or an
520 -- absolute path without drive letter, the letter of the current drive
521 -- will start the returned path. If Case_Sensitive is True (the default),
522 -- then this drive letter will be forced to upper case ("C:\...").
523 --
524 -- If Resolve_Links is set to True, then the symbolic links, on systems
525 -- that support them, will be fully converted to the name of the file or
526 -- directory pointed to. This is slightly less efficient, since it
527 -- requires system calls.
528 --
529 -- If Name cannot be resolved, is invalid (for example if it is too big) or
530 -- is null on entry (for example if there is symbolic link circularity,
531 -- e.g. A is a symbolic link for B, and B is a symbolic link for A), then
532 -- Normalize_Pathname returns an empty string.
533 --
534 -- For case-sensitive file systems, the value of Case_Sensitive parameter
535 -- is ignored. For file systems that are not case-sensitive, such as
536 -- Windows, if this parameter is set to False, then the file and directory
537 -- names are folded to lower case. This allows checking whether two files
538 -- are the same by applying this function to their names and comparing the
539 -- results. If Case_Sensitive is set to True, this function does not change
540 -- the casing of file and directory names.
541
542 function Open_Append
543 (Name : String;
544 Fmode : Mode) return File_Descriptor;
545 -- Opens file Name for appending, returning its file descriptor. File
546 -- descriptor returned is Invalid_FD if the file cannot be successfully
547 -- opened.
548
549 function Open_Read
550 (Name : String;
551 Fmode : Mode) return File_Descriptor;
552 -- Open file Name for reading, returning its file descriptor. File
553 -- descriptor returned is Invalid_FD if the file cannot be opened.
554
555 function Open_Read_Write
556 (Name : String;
557 Fmode : Mode) return File_Descriptor;
558 -- Open file Name for both reading and writing, returning its file
559 -- descriptor. File descriptor returned is Invalid_FD if the file
560 -- cannot be opened.
561
562 function Read
563 (FD : File_Descriptor;
564 A : System.Address;
565 N : Integer) return Integer;
566 -- Read N bytes to address A from file referenced by FD. Returned value is
567 -- count of bytes actually read, which can be less than N at EOF.
568
569 procedure Rename_File
570 (Old_Name : String;
571 New_Name : String;
572 Success : out Boolean);
573 -- Rename a file. Success is set True or False indicating if the rename is
574 -- successful or not.
575 --
576 -- WARNING: In one very important respect, this function is significantly
577 -- non-portable. If New_Name already exists then on Unix systems, the call
578 -- deletes the existing file, and the call signals success. On Windows, the
579 -- call fails, without doing the rename operation. See also the procedure
580 -- Ada.Directories.Rename, which portably provides the windows semantics,
581 -- i.e. fails if the output file already exists.
582
583 -- The following defines the mode for the Copy_File procedure below. Note
584 -- that "time stamps and other file attributes" in the descriptions below
585 -- refers to the creation and last modification times, and also the file
586 -- access (read/write/execute) status flags.
587
588 procedure Set_Close_On_Exec
589 (FD : File_Descriptor;
590 Close_On_Exec : Boolean;
591 Status : out Boolean);
592 -- When Close_On_Exec is True, mark FD to be closed automatically when new
593 -- program is executed by the calling process (i.e. prevent FD from being
594 -- inherited by child processes). When Close_On_Exec is False, mark FD to
595 -- not be closed on exec (i.e. allow it to be inherited). Status is False
596 -- if the operation could not be performed.
597
598 S_Owner : constant := 1;
599 S_Group : constant := 2;
600 S_Others : constant := 4;
601 -- Constants for use in Mode parameter to Set_Executable
602
603 procedure Set_Executable (Name : String; Mode : Positive := S_Owner);
604 -- Change permissions on the file given by Name to make it executable
605 -- for its owner, group or others, according to the setting of Mode.
606 -- As indicated, the default if no Mode parameter is given is owner.
607
608 procedure Set_File_Last_Modify_Time_Stamp (Name : String; Time : OS_Time);
609 -- Given the name of a file or directory, Name, set the last modification
610 -- time stamp. This function must be used for an unopened file.
611
612 procedure Set_Non_Readable (Name : String);
613 -- Change permissions on the named file to make it non-readable for
614 -- its owner. The writable and executable permissions are not
615 -- modified.
616
617 procedure Set_Non_Writable (Name : String);
618 -- Change permissions on the named file to make it non-writable for its
619 -- owner. The readable and executable permissions are not modified.
620
621 procedure Set_Read_Only (Name : String) renames Set_Non_Writable;
622 -- This renaming is provided for backwards compatibility with previous
623 -- versions. The use of Set_Non_Writable is preferred (clearer name).
624
625 procedure Set_Readable (Name : String);
626 -- Change permissions on the named file to make it readable for its
627 -- owner.
628
629 procedure Set_Writable (Name : String);
630 -- Change permissions on the named file to make it writable for its owner
631
632 function Write
633 (FD : File_Descriptor;
634 A : System.Address;
635 N : Integer) return Integer;
636 -- Write N bytes from address A to file referenced by FD. The returned
637 -- value is the number of bytes written, which can be less than N if a
638 -- disk full condition was detected.
639
640 -- The following section contains low-level routines using addresses to
641 -- pass file name and executable name. In each routine the name must be
642 -- Nul-Terminated. For complete documentation refer to the equivalent
643 -- routine (using String in place of C_File_Name) defined above.
644
645 subtype C_File_Name is System.Address;
646 -- This subtype is used to document that a parameter is the address of a
647 -- null-terminated string containing the name of a file.
648
649 -- All the following functions need comments ???
650
651 procedure Copy_File
652 (Name : C_File_Name;
653 Pathname : C_File_Name;
654 Success : out Boolean;
655 Mode : Copy_Mode := Copy;
656 Preserve : Attribute := Time_Stamps);
657
658 procedure Copy_Time_Stamps
659 (Source : C_File_Name;
660 Dest : C_File_Name;
661 Success : out Boolean);
662
663 function Create_File
664 (Name : C_File_Name;
665 Fmode : Mode) return File_Descriptor;
666
667 function Create_New_File
668 (Name : C_File_Name;
669 Fmode : Mode) return File_Descriptor;
670
671 procedure Delete_File (Name : C_File_Name; Success : out Boolean);
672
673 function File_Time_Stamp (Name : C_File_Name) return OS_Time;
674 -- Returns Invalid_Time is Name doesn't correspond to an existing file
675
676 function Is_Directory (Name : C_File_Name) return Boolean;
677 function Is_Executable_File (Name : C_File_Name) return Boolean;
678 function Is_Readable_File (Name : C_File_Name) return Boolean;
679 function Is_Regular_File (Name : C_File_Name) return Boolean;
680 function Is_Symbolic_Link (Name : C_File_Name) return Boolean;
681 function Is_Writable_File (Name : C_File_Name) return Boolean;
682
683 function Locate_Regular_File
684 (File_Name : C_File_Name;
685 Path : C_File_Name) return String_Access;
686
687 function Open_Append
688 (Name : C_File_Name;
689 Fmode : Mode) return File_Descriptor;
690
691 function Open_Read
692 (Name : C_File_Name;
693 Fmode : Mode) return File_Descriptor;
694
695 function Open_Read_Write
696 (Name : C_File_Name;
697 Fmode : Mode) return File_Descriptor;
698
699 procedure Rename_File
700 (Old_Name : C_File_Name;
701 New_Name : C_File_Name;
702 Success : out Boolean);
703
704 ------------------
705 -- Subprocesses --
706 ------------------
707
708 subtype Argument_List is String_List;
709 -- Type used for argument list in call to Spawn. The lower bound of the
710 -- array should be 1, and the length of the array indicates the number of
711 -- arguments.
712
713 subtype Argument_List_Access is String_List_Access;
714 -- Type used to return Argument_List without dragging in secondary stack.
715 -- Note that there is a Free procedure declared for this subtype which
716 -- frees the array and all referenced strings.
717
718 type Process_Id is private;
719 -- A private type used to identify a process activated by the following
720 -- non-blocking calls. The only meaningful operation on this type is a
721 -- comparison for equality.
722
723 Invalid_Pid : constant Process_Id;
724 -- A special value used to indicate errors, as described below
725
726 function Current_Process_Id return Process_Id;
727 -- Returns the current process id or Invalid_Pid if not supported by the
728 -- runtime.
729
730 function Argument_String_To_List
731 (Arg_String : String) return Argument_List_Access;
732 -- Take a string that is a program and its arguments and parse it into an
733 -- Argument_List. Note that the result is allocated on the heap, and must
734 -- be freed by the programmer (when it is no longer needed) to avoid
735 -- memory leaks.
736 -- On Windows, backslashes are used as directory separators. On Unix,
737 -- however, they are used to escape the following character, so that for
738 -- instance "-d=name\ with\ space" is a single argument. In the result
739 -- list, the backslashes have been cleaned up when needed. The previous
740 -- example will thus result a single-element array, where the element is
741 -- "-d=name with space" (Unix) or "-d=name\ with\ space" (windows).
742
743 procedure Kill (Pid : Process_Id; Hard_Kill : Boolean := True);
744 -- Kill the process designated by Pid. Does nothing if Pid is Invalid_Pid
745 -- or on platforms where it is not supported, such as VxWorks. Hard_Kill
746 -- is True by default, and when True the process is terminated immediately.
747 -- If Hard_Kill is False, then a signal SIGINT is sent to the process on
748 -- POSIX OS or a ctrl-C event on Windows, allowing the process a chance to
749 -- terminate properly using a corresponding handler.
750
751 procedure Kill_Process_Tree (Pid : Process_Id; Hard_Kill : Boolean := True);
752 -- Kill the process designated by Pid and all it's children processes.
753 -- Does nothing if Pid is Invalid_Pid or on platforms where it is not
754 -- supported, such as VxWorks. Hard_Kill is True by default, and when True
755 -- the processes are terminated immediately. If Hard_Kill is False, then a
756 -- signal SIGINT is sent to the processes on POSIX OS or a ctrl-C event
757 -- on Windows, allowing the processes a chance to terminate properly
758 -- using a corresponding handler.
759 --
760 -- Note that this routine is not atomic and is supported only on Linux
761 -- and Windows. On other OS it will only kill the process identified by
762 -- Pid.
763
764 function Non_Blocking_Spawn
765 (Program_Name : String;
766 Args : Argument_List) return Process_Id;
767 -- This is a non blocking call. The Process_Id of the spawned process is
768 -- returned. Parameters are to be used as in Spawn. If Invalid_Pid is
769 -- returned the program could not be spawned.
770 --
771 -- Spawning processes from tasking programs is not recommended. See
772 -- "NOTE: Spawn in tasking programs" below.
773 --
774 -- This function will always return Invalid_Pid under VxWorks, since there
775 -- is no notion of executables under this OS.
776
777 function Non_Blocking_Spawn
778 (Program_Name : String;
779 Args : Argument_List;
780 Output_File_Descriptor : File_Descriptor;
781 Err_To_Out : Boolean := True) return Process_Id;
782 -- Similar to the procedure above, but redirects the output to the file
783 -- designated by Output_File_Descriptor. If Err_To_Out is True, then the
784 -- Standard Error output is also redirected. Invalid_Pid is returned
785 -- if the program could not be spawned successfully.
786 --
787 -- Spawning processes from tasking programs is not recommended. See
788 -- "NOTE: Spawn in tasking programs" below.
789 --
790 -- This function will always return Invalid_Pid under VxWorks, since there
791 -- is no notion of executables under this OS.
792
793 function Non_Blocking_Spawn
794 (Program_Name : String;
795 Args : Argument_List;
796 Output_File : String;
797 Err_To_Out : Boolean := True) return Process_Id;
798 -- Similar to the procedure above, but saves the output of the command to
799 -- a file with the name Output_File.
800 --
801 -- Invalid_Pid is returned if the output file could not be created or if
802 -- the program could not be spawned successfully.
803 --
804 -- Spawning processes from tasking programs is not recommended. See
805 -- "NOTE: Spawn in tasking programs" below.
806 --
807 -- This function will always return Invalid_Pid under VxWorks, since there
808 -- is no notion of executables under this OS.
809
810 function Non_Blocking_Spawn
811 (Program_Name : String;
812 Args : Argument_List;
813 Stdout_File : String;
814 Stderr_File : String) return Process_Id;
815 -- Similar to the procedure above, but saves the standard output of the
816 -- command to a file with the name Stdout_File and the standard output
817 -- of the command to a file with the name Stderr_File.
818
819 procedure Normalize_Arguments (Args : in out Argument_List);
820 -- Normalize all arguments in the list. This ensure that the argument list
821 -- is compatible with the running OS and will works fine with Spawn and
822 -- Non_Blocking_Spawn for example. If Normalize_Arguments is called twice
823 -- on the same list it will do nothing the second time. Note that Spawn
824 -- and Non_Blocking_Spawn call Normalize_Arguments automatically, but
825 -- since there is a guarantee that a second call does nothing, this
826 -- internal call will have no effect if Normalize_Arguments is called
827 -- before calling Spawn. The call to Normalize_Arguments assumes that the
828 -- individual referenced arguments in Argument_List are on the heap, and
829 -- may free them and reallocate if they are modified.
830
831 function Pid_To_Integer (Pid : Process_Id) return Integer;
832 -- Convert a process id to an Integer. Useful for writing hash functions
833 -- for type Process_Id or to compare two Process_Id (e.g. for sorting).
834
835 procedure Spawn
836 (Program_Name : String;
837 Args : Argument_List;
838 Success : out Boolean);
839 -- This procedure spawns a program with a given list of arguments. The
840 -- first parameter of is the name of the executable. The second parameter
841 -- contains the arguments to be passed to this program. Success is False
842 -- if the named program could not be spawned or its execution completed
843 -- unsuccessfully. Note that the caller will be blocked until the
844 -- execution of the spawned program is complete. For maximum portability,
845 -- use a full path name for the Program_Name argument. On some systems
846 -- (notably Unix systems) a simple file name may also work (if the
847 -- executable can be located in the path).
848 --
849 -- Spawning processes from tasking programs is not recommended. See
850 -- "NOTE: Spawn in tasking programs" below.
851 --
852 -- Note: Arguments in Args that contain spaces and/or quotes such as
853 -- "--GCC=gcc -v" or "--GCC=""gcc -v""" are not portable across all
854 -- operating systems, and would not have the desired effect if they were
855 -- passed directly to the operating system. To avoid this problem, Spawn
856 -- makes an internal call to Normalize_Arguments, which ensures that such
857 -- arguments are modified in a manner that ensures that the desired effect
858 -- is obtained on all operating systems. The caller may call
859 -- Normalize_Arguments explicitly before the call (e.g. to print out the
860 -- exact form of arguments passed to the operating system). In this case
861 -- the guarantee a second call to Normalize_Arguments has no effect
862 -- ensures that the internal call will not affect the result. Note that
863 -- the implicit call to Normalize_Arguments may free and reallocate some
864 -- of the individual arguments.
865 --
866 -- This function will always set Success to False under VxWorks and other
867 -- similar operating systems which have no notion of the concept of
868 -- dynamically executable file. Otherwise Success is set True if the exit
869 -- status of the spawned process is zero.
870
871 function Spawn
872 (Program_Name : String;
873 Args : Argument_List) return Integer;
874 -- Similar to the above procedure, but returns the actual status returned
875 -- by the operating system, or -1 under VxWorks and any other similar
876 -- operating systems which have no notion of separately spawnable programs.
877 --
878 -- Spawning processes from tasking programs is not recommended. See
879 -- "NOTE: Spawn in tasking programs" below.
880
881 procedure Spawn
882 (Program_Name : String;
883 Args : Argument_List;
884 Output_File_Descriptor : File_Descriptor;
885 Return_Code : out Integer;
886 Err_To_Out : Boolean := True);
887 -- Similar to the procedure above, but redirects the output to the file
888 -- designated by Output_File_Descriptor. If Err_To_Out is True, then the
889 -- Standard Error output is also redirected.
890 -- Return_Code is set to the status code returned by the operating system
891 --
892 -- Spawning processes from tasking programs is not recommended. See
893 -- "NOTE: Spawn in tasking programs" below.
894
895 procedure Spawn
896 (Program_Name : String;
897 Args : Argument_List;
898 Output_File : String;
899 Success : out Boolean;
900 Return_Code : out Integer;
901 Err_To_Out : Boolean := True);
902 -- Similar to the procedure above, but saves the output of the command to
903 -- a file with the name Output_File.
904 --
905 -- Success is set to True if the command is executed and its output
906 -- successfully written to the file. If Success is True, then Return_Code
907 -- will be set to the status code returned by the operating system.
908 -- Otherwise, Return_Code is undefined.
909 --
910 -- Spawning processes from tasking programs is not recommended. See
911 -- "NOTE: Spawn in tasking programs" below.
912
913 procedure Wait_Process (Pid : out Process_Id; Success : out Boolean);
914 -- Wait for the completion of any of the processes created by previous
915 -- calls to Non_Blocking_Spawn. The caller will be suspended until one of
916 -- these processes terminates (normally or abnormally). If any of these
917 -- subprocesses terminates prior to the call to Wait_Process (and has not
918 -- been returned by a previous call to Wait_Process), then the call to
919 -- Wait_Process is immediate. Pid identifies the process that has
920 -- terminated (matching the value returned from Non_Blocking_Spawn).
921 -- Success is set to True if this sub-process terminated successfully. If
922 -- Pid = Invalid_Pid, there were no subprocesses left to wait on.
923 --
924 -- This function will always set success to False under VxWorks, since
925 -- there is no notion of executables under this OS.
926
927 -------------------------------------
928 -- NOTE: Spawn in Tasking Programs --
929 -------------------------------------
930
931 -- Spawning processes in tasking programs using the above Spawn and
932 -- Non_Blocking_Spawn subprograms is not recommended, because there are
933 -- subtle interactions between creating a process and signals/locks that
934 -- can cause trouble. These issues are not specific to Ada; they depend
935 -- primarily on the operating system.
936
937 -- If you need to spawn processes in a tasking program, you will need to
938 -- understand the semantics of your operating system, and you are likely to
939 -- write non-portable code, because operating systems differ in this area.
940
941 -- The Spawn and Non_Blocking_Spawn subprograms call the following
942 -- operating system functions:
943
944 -- On Windows: spawnvp (blocking) or CreateProcess (non-blocking)
945
946 -- On Solaris: fork1, followed in the child process by execv
947
948 -- On other Unix-like systems: fork, followed in the child
949 -- process by execv.
950
951 -- On vxworks, spawning of processes is not supported
952
953 -- For details, look at the functions __gnat_portable_spawn and
954 -- __gnat_portable_no_block_spawn in adaint.c.
955
956 -- You should read the operating-system-specific documentation for the
957 -- above functions, paying special attention to subtle interactions with
958 -- threading, signals, locks, and file descriptors. Most of the issues are
959 -- related to the fact that on Unix, there is a window of time between fork
960 -- and execv; Windows does not have this problem, because spawning is done
961 -- in a single operation.
962
963 -- On Posix-compliant systems, such as Linux, fork duplicates just the
964 -- calling thread. (On Solaris, fork1 is the Posix-compliant version of
965 -- fork.)
966
967 -- You should avoid using signals while spawning. This includes signals
968 -- used internally by the Ada run-time system, such as timer signals used
969 -- to implement delay statements.
970
971 -- It is best to spawn any subprocesses very early, before the parent
972 -- process creates tasks, locks, or installs signal handlers. Certainly
973 -- avoid doing simultaneous spawns from multiple threads of the same
974 -- process.
975
976 -- There is no problem spawning a subprocess that uses tasking: the
977 -- problems are caused only by tasking in the parent.
978
979 -- If the parent is using tasking, and needs to spawn subprocesses at
980 -- arbitrary times, one technique is for the parent to spawn (very early)
981 -- a particular spawn-manager subprocess whose job is to spawn other
982 -- processes. The spawn-manager must avoid tasking. The parent sends
983 -- messages to the spawn-manager requesting it to spawn processes, using
984 -- whatever inter-process communication mechanism you like, such as
985 -- sockets.
986
987 -- In short, mixing spawning of subprocesses with tasking is a tricky
988 -- business, and should be avoided if possible, but if it is necessary,
989 -- the above guidelines should be followed, and you should beware of
990 -- portability problems.
991
992 -------------------
993 -- Miscellaneous --
994 -------------------
995
996 function Errno return Integer;
997 pragma Import (C, Errno, "__get_errno");
998 -- Return the task-safe last error number
999
1000 function Errno_Message
1001 (Err : Integer := Errno;
1002 Default : String := "") return String;
1003 -- Return a message describing the given Errno value. If none is provided
1004 -- by the system, return Default if not empty, else return a generic
1005 -- message indicating the numeric errno value.
1006
1007 function Getenv (Name : String) return String_Access;
1008 -- Get the value of the environment variable. Returns an access to the
1009 -- empty string if the environment variable does not exist or has an
1010 -- explicit null value (in some operating systems these are distinct
1011 -- cases, in others they are not; this interface abstracts away that
1012 -- difference. The argument is allocated on the heap (even in the null
1013 -- case), and needs to be freed explicitly when no longer needed to avoid
1014 -- memory leaks.
1015
1016 procedure OS_Abort;
1017 pragma Import (C, OS_Abort, "abort");
1018 pragma No_Return (OS_Abort);
1019 -- Exit to OS signalling an abort (traceback or other appropriate
1020 -- diagnostic information should be given if possible, or entry made to
1021 -- the debugger if that is possible).
1022
1023 procedure OS_Exit (Status : Integer);
1024 pragma No_Return (OS_Exit);
1025 -- Exit to OS with given status code (program is terminated). Note that
1026 -- this is abrupt termination. All tasks are immediately terminated. There
1027 -- are no finalization or other Ada-specific cleanup actions performed. On
1028 -- systems with atexit handlers (such as Unix and Windows), atexit handlers
1029 -- are called.
1030
1031 type OS_Exit_Subprogram is access procedure (Status : Integer);
1032
1033 procedure OS_Exit_Default (Status : Integer);
1034 pragma No_Return (OS_Exit_Default);
1035 -- Default implementation of procedure OS_Exit
1036
1037 OS_Exit_Ptr : OS_Exit_Subprogram := OS_Exit_Default'Access;
1038 -- OS_Exit is implemented through this access value. It it then possible to
1039 -- change the implementation of OS_Exit by redirecting OS_Exit_Ptr to an
1040 -- other implementation.
1041
1042 procedure Set_Errno (Errno : Integer);
1043 pragma Import (C, Set_Errno, "__set_errno");
1044 -- Set the task-safe error number
1045
1046 procedure Setenv (Name : String; Value : String);
1047 -- Set the value of the environment variable Name to Value. This call
1048 -- modifies the current environment, but does not modify the parent
1049 -- process environment. After a call to Setenv, Getenv (Name) will always
1050 -- return a String_Access referencing the same String as Value. This is
1051 -- true also for the null string case (the actual effect may be to either
1052 -- set an explicit null as the value, or to remove the entry, this is
1053 -- operating system dependent). Note that any following calls to Spawn
1054 -- will pass an environment to the spawned process that includes the
1055 -- changes made by Setenv calls.
1056
1057 Directory_Separator : constant Character;
1058 -- The character that is used to separate parts of a pathname
1059
1060 Path_Separator : constant Character;
1061 -- The character to separate paths in an environment variable value
1062
1063 private
1064 pragma Import (C, Path_Separator, "__gnat_path_separator");
1065 pragma Import (C, Directory_Separator, "__gnat_dir_separator");
1066 pragma Import (C, Current_Time, "__gnat_current_time");
1067 pragma Import (C, Current_Process_Id, "__gnat_current_process_id");
1068
1069 type OS_Time is
1070 range -(2 ** (Standard'Address_Size - Integer'(1))) ..
1071 +(2 ** (Standard'Address_Size - Integer'(1)) - 1);
1072 -- Type used for timestamps in the compiler. This type is used to hold
1073 -- time stamps, but may have a different representation than C's time_t.
1074 -- This type needs to match the declaration of OS_Time in adaint.h.
1075
1076 -- Add pragma Inline statements for comparison operations on OS_Time. It
1077 -- would actually be nice to use pragma Import (Intrinsic) here, but this
1078 -- was not properly supported till GNAT 3.15a, so that would cause
1079 -- bootstrap path problems. To be changed later ???
1080
1081 Invalid_Time : constant OS_Time := -1;
1082 -- This value should match the return value from __gnat_file_time_*
1083
1084 pragma Inline ("<");
1085 pragma Inline (">");
1086 pragma Inline ("<=");
1087 pragma Inline (">=");
1088
1089 type Process_Id is new Integer;
1090 Invalid_Pid : constant Process_Id := -1;
1091
1092 end System.OS_Lib;