1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . O S _ L I B --
9 -- Copyright (C) 1995-2012, Free Software Foundation, Inc. --
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. --
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. --
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/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- Operating system interface facilities
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.
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.
44 -- Except where specifically noted, these routines are portable across all
45 -- GNAT implementations on all supported operating systems.
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).
56 package System.OS_Lib is
57 pragma Elaborate_Body (OS_Lib);
59 -----------------------
60 -- String Operations --
61 -----------------------
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.
67 subtype String_Access is Strings.String_Access;
69 function "=" (Left, Right : String_Access) return Boolean
72 procedure Free (X : in out String_Access) renames Strings.Free;
74 subtype String_List is Strings.String_List;
76 function "=" (Left, Right : String_List) return Boolean
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."&";
88 subtype String_List_Access is Strings.String_List_Access;
90 function "=" (Left, Right : String_List_Access) return Boolean
93 procedure Free (Arg : in out String_List_Access)
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).
110 Invalid_Time : constant OS_Time;
111 -- A special unique value used to flag an invalid time stamp value
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
121 function Current_Time return OS_Time;
122 -- Return the system clock value as OS_Time
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
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.
142 Year : out Year_Type;
143 Month : out Month_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.
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
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).
168 type File_Descriptor is new Integer;
169 -- Corresponds to the int file handle values used in the C routines
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
176 Invalid_FD : constant File_Descriptor := -1;
177 -- File descriptor returned when error in opening/creating file
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.
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.
196 function Open_Read_Write
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.
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.
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.
215 function Create_New_File
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.
223 Temp_File_Len : constant Integer := 12;
224 -- Length of name returned by Create_Temp_File call (GNAT-XXXXXX & NUL)
226 subtype Temp_File_Name is String (1 .. Temp_File_Len);
227 -- String subtype set by Create_Temp_File
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.
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.
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
252 -- The file is opened in binary mode (no text translation).
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.
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.
268 -- The file is opened in text mode
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.
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).
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).
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.
295 procedure Delete_File (Name : String; Success : out Boolean);
296 -- Deletes file. Success is set True or False indicating if the delete is
299 procedure Rename_File
302 Success : out Boolean);
303 -- Rename a file. Success is set True or False indicating if the rename is
304 -- successful or not.
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.
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.
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.
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.
329 -- Copy time stamps from source file to target file. All other
330 -- attributes are set to normal default values for file creation.
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.
338 -- No attributes are copied. All attributes including the time stamp
339 -- values are set to normal default values for file creation.
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.
346 -- Note: Time_Stamps and Full are not supported on VMS and VxWorks 5
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
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.
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.
374 -- Note: this procedure is not supported on VMS and VxWorks 5. On these
375 -- platforms, Success is always set to False.
378 (FD : File_Descriptor;
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.
385 (FD : File_Descriptor;
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.
392 Seek_Cur : constant := 1;
393 Seek_End : constant := 2;
394 Seek_Set : constant := 0;
395 -- Used to indicate origin for Lseek call
398 (FD : File_Descriptor;
399 offset : Long_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).
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
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.
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.
419 function Normalize_Pathname
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.
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:\...").
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.
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.
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.
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.
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.
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.
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.
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
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
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
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.
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.
514 procedure Set_Writable (Name : String);
515 -- Change permissions on the named file to make it writable for its owner
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.
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).
525 procedure Set_Executable (Name : String);
526 -- Change permissions on the named file to make it executable for its owner
528 procedure Set_Readable (Name : String);
529 -- Change permissions on the named file to make it readable for its
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
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.
545 -- Note that this function allocates memory for the returned value. This
546 -- memory needs to be deallocated after use.
548 function Locate_Regular_File
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
563 -- Note that this function allocates some memory for the returned value.
564 -- This memory needs to be deallocated after use.
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.
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.
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.
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.
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.
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.
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.
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.
601 -- All the following functions need comments ???
605 Fmode : Mode) return File_Descriptor;
607 function Open_Read_Write
609 Fmode : Mode) return File_Descriptor;
613 Fmode : Mode) return File_Descriptor;
615 function Create_New_File
617 Fmode : Mode) return File_Descriptor;
619 procedure Delete_File (Name : C_File_Name; Success : out Boolean);
621 procedure Rename_File
622 (Old_Name : C_File_Name;
623 New_Name : C_File_Name;
624 Success : out Boolean);
628 Pathname : C_File_Name;
629 Success : out Boolean;
630 Mode : Copy_Mode := Copy;
631 Preserve : Attribute := Time_Stamps);
633 procedure Copy_Time_Stamps
634 (Source, Dest : C_File_Name;
635 Success : out Boolean);
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
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;
647 function Locate_Regular_File
648 (File_Name : C_File_Name;
649 Path : C_File_Name) return String_Access;
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
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.
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.
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).
691 -- Spawning processes from tasking programs is not recommended. See
692 -- "NOTE: Spawn in tasking programs" below.
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.
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.
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.
720 -- Spawning processes from tasking programs is not recommended. See
721 -- "NOTE: Spawn in tasking programs" below.
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
734 -- Spawning processes from tasking programs is not recommended. See
735 -- "NOTE: Spawn in tasking programs" below.
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.
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.
752 -- Spawning processes from tasking programs is not recommended. See
753 -- "NOTE: Spawn in tasking programs" below.
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.
760 Invalid_Pid : constant Process_Id;
761 -- A special value used to indicate errors, as described below
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).
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.
774 -- Spawning processes from tasking programs is not recommended. See
775 -- "NOTE: Spawn in tasking programs" below.
777 -- This function will always return Invalid_Pid under VxWorks, since there
778 -- is no notion of executables under this OS.
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.
790 -- Spawning processes from tasking programs is not recommended. See
791 -- "NOTE: Spawn in tasking programs" below.
793 -- This function will always return Invalid_Pid under VxWorks, since there
794 -- is no notion of executables under this OS.
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.
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
809 -- Spawning processes from tasking programs is not recommended. See
810 -- "NOTE: Spawn in tasking programs" below.
812 -- This function will always return Invalid_Pid under VxWorks, since there
813 -- is no notion of executables under this OS.
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.
826 -- This function will always set success to False under VxWorks, since
827 -- there is no notion of executables under this OS.
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
836 -------------------------------------
837 -- NOTE: Spawn in Tasking Programs --
838 -------------------------------------
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.
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.
850 -- The Spawn and Non_Blocking_Spawn subprograms call the following
851 -- operating system functions:
853 -- On Windows: spawnvp (blocking) or CreateProcess (non-blocking)
855 -- On Solaris: fork1, followed in the child process by execv
857 -- On other Unix-like systems, and on VMS: fork, followed in the child
860 -- On vxworks, nucleus, and RTX, spawning of processes is not supported
862 -- For details, look at the functions __gnat_portable_spawn and
863 -- __gnat_portable_no_block_spawn in adaint.c.
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.
872 -- On Posix-compliant systems, such as Linux, fork duplicates just the
873 -- calling thread. (On Solaris, fork1 is the Posix-compliant version of
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.
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
885 -- There is no problem spawning a subprocess that uses tasking: the
886 -- problems are caused only by tasking in the parent.
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
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.
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
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.
925 procedure OS_Exit (Status : Integer);
926 pragma No_Return (OS_Exit);
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
934 type OS_Exit_Subprogram is access procedure (Status : Integer);
936 procedure OS_Exit_Default (Status : Integer);
937 pragma No_Return (OS_Exit_Default);
938 -- Default implementation of procedure OS_Exit
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.
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).
952 function Errno return Integer;
953 pragma Import (C, Errno, "__get_errno");
954 -- Return the task-safe last error number
956 procedure Set_Errno (Errno : Integer);
957 pragma Import (C, Set_Errno, "__set_errno");
958 -- Set the task-safe error number
960 Directory_Separator : constant Character;
961 -- The character that is used to separate parts of a pathname
963 Path_Separator : constant Character;
964 -- The character to separate paths in an environment variable value
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");
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.
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 ???
983 Invalid_Time : constant OS_Time := -1;
984 -- This value should match the return value from __gnat_file_time_*
988 pragma Inline ("<=");
989 pragma Inline (">=");
991 type Process_Id is new Integer;
992 Invalid_Pid : constant Process_Id := -1;
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