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);
60 -----------------------
61 -- String Operations --
62 -----------------------
64 -- These are reexported from package Strings (which was introduced to
65 -- avoid different packages declaring different types unnecessarily).
66 -- See package System.Strings for details.
68 subtype String_Access is Strings.String_Access;
70 function "=" (Left, Right : String_Access) return Boolean
73 procedure Free (X : in out String_Access) renames Strings.Free;
75 subtype String_List is Strings.String_List;
77 function "=" (Left, Right : String_List) return Boolean
80 function "&" (Left : String_Access; Right : String_Access)
81 return String_List renames Strings."&";
82 function "&" (Left : String_Access; Right : String_List)
83 return String_List renames Strings."&";
84 function "&" (Left : String_List; Right : String_Access)
85 return String_List renames Strings."&";
86 function "&" (Left : String_List; Right : String_List)
87 return String_List renames Strings."&";
89 subtype String_List_Access is Strings.String_List_Access;
91 function "=" (Left, Right : String_List_Access) return Boolean
94 procedure Free (Arg : in out String_List_Access)
101 type OS_Time is private;
102 -- The OS's notion of time is represented by the private type OS_Time.
103 -- This is the type returned by the File_Time_Stamp functions to obtain
104 -- the time stamp of a specified file. Functions and a procedure (modeled
105 -- after the similar subprograms in package Calendar) are provided for
106 -- extracting information from a value of this type. Although these are
107 -- called GM, the intention is not that they provide GMT times in all
108 -- cases but rather the actual (time-zone independent) time stamp of the
109 -- file (of course in Unix systems, this *is* in GMT form).
111 Invalid_Time : constant OS_Time;
112 -- A special unique value used to flag an invalid time stamp value
114 subtype Year_Type is Integer range 1900 .. 2099;
115 subtype Month_Type is Integer range 1 .. 12;
116 subtype Day_Type is Integer range 1 .. 31;
117 subtype Hour_Type is Integer range 0 .. 23;
118 subtype Minute_Type is Integer range 0 .. 59;
119 subtype Second_Type is Integer range 0 .. 59;
120 -- Declarations similar to those in Calendar, breaking down the time
122 function Current_Time return OS_Time;
123 -- Return the system clock value as OS_Time
125 function GM_Year (Date : OS_Time) return Year_Type;
126 function GM_Month (Date : OS_Time) return Month_Type;
127 function GM_Day (Date : OS_Time) return Day_Type;
128 function GM_Hour (Date : OS_Time) return Hour_Type;
129 function GM_Minute (Date : OS_Time) return Minute_Type;
130 function GM_Second (Date : OS_Time) return Second_Type;
131 -- Functions to extract information from OS_Time value
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 function "<=" (X, Y : OS_Time) return Boolean;
137 -- Basic comparison operators on OS_Time with obvious meanings. Note that
138 -- these have Intrinsic convention, so for example it is not permissible
139 -- to create accesses to any of these functions.
143 Year : out Year_Type;
144 Month : out Month_Type;
146 Hour : out Hour_Type;
147 Minute : out Minute_Type;
148 Second : out Second_Type);
149 -- Analogous to the Split routine in Ada.Calendar, takes an OS_Time and
150 -- provides a representation of it as a set of component parts, to be
151 -- interpreted as a date point in UTC.
157 -- These routines give access to the open/creat/close/read/write level of
158 -- I/O routines in the typical C library (these functions are not part of
159 -- the ANSI C standard, but are typically available in all systems). See
160 -- also package Interfaces.C_Streams for access to the stream level
163 -- Note on file names. If a file name is passed as type String in any of
164 -- the following specifications, then the name is a normal Ada string and
165 -- need not be NUL-terminated. However, a trailing NUL character is
166 -- permitted, and will be ignored (more accurately, the NUL and any
167 -- characters that follow it will be ignored).
169 type File_Descriptor is new Integer;
170 -- Corresponds to the int file handle values used in the C routines
172 Standin : constant File_Descriptor := 0;
173 Standout : constant File_Descriptor := 1;
174 Standerr : constant File_Descriptor := 2;
175 -- File descriptors for standard input output files
177 Invalid_FD : constant File_Descriptor := -1;
178 -- File descriptor returned when error in opening/creating file
180 type Mode is (Binary, Text);
181 for Mode'Size use Integer'Size;
182 for Mode use (Binary => 0, Text => 1);
183 -- Used in all the Open and Create calls to specify if the file is to be
184 -- opened in binary mode or text mode. In systems like Unix, this has no
185 -- effect, but in systems capable of text mode translation, the use of
186 -- Text as the mode parameter causes the system to do CR/LF translation
187 -- and also to recognize the DOS end of file character on input. The use
188 -- of Text where appropriate allows programs to take a portable Unix view
189 -- of DOS-format files and process them appropriately.
193 Fmode : Mode) return File_Descriptor;
194 -- Open file Name for reading, returning file descriptor File descriptor
195 -- returned is Invalid_FD if file cannot be opened.
197 function Open_Read_Write
199 Fmode : Mode) return File_Descriptor;
200 -- Open file Name for both reading and writing, returning file descriptor.
201 -- File descriptor returned is Invalid_FD if file cannot be opened.
205 Fmode : Mode) return File_Descriptor;
206 -- Creates new file with given name for writing, returning file descriptor
207 -- for subsequent use in Write calls. If the file already exists, it is
208 -- overwritten. File descriptor returned is Invalid_FD if file cannot be
209 -- successfully created.
211 function Create_Output_Text_File (Name : String) return File_Descriptor;
212 -- Creates new text file with given name suitable to redirect standard
213 -- output, returning file descriptor. File descriptor returned is
214 -- Invalid_FD if file cannot be successfully created.
216 function Create_New_File
218 Fmode : Mode) return File_Descriptor;
219 -- Create new file with given name for writing, returning file descriptor
220 -- for subsequent use in Write calls. This differs from Create_File in
221 -- that it fails if the file already exists. File descriptor returned is
222 -- Invalid_FD if the file exists or cannot be created.
224 Temp_File_Len : constant Integer := 12;
225 -- Length of name returned by Create_Temp_File call (GNAT-XXXXXX & NUL)
227 subtype Temp_File_Name is String (1 .. Temp_File_Len);
228 -- String subtype set by Create_Temp_File
230 procedure Create_Temp_File
231 (FD : out File_Descriptor;
232 Name : out Temp_File_Name);
233 -- Create and open for writing a temporary file in the current working
234 -- directory. The name of the file and the File Descriptor are returned.
235 -- The File Descriptor returned is Invalid_FD in the case of failure. No
236 -- mode parameter is provided. Since this is a temporary file, there is no
237 -- point in doing text translation on it.
239 -- On some operating systems, the maximum number of temp files that can be
240 -- created with this procedure may be limited. When the maximum is reached,
241 -- this procedure returns Invalid_FD. On some operating systems, there may
242 -- be a race condition between processes trying to create temp files at the
243 -- same time in the same directory using this procedure.
245 procedure Create_Temp_File
246 (FD : out File_Descriptor;
247 Name : out String_Access);
248 -- Create and open for writing a temporary file in the current working
249 -- directory. The name of the file and the File Descriptor are returned.
250 -- It is the responsibility of the caller to deallocate the access value
253 -- The file is opened in binary mode (no text translation).
255 -- This procedure will always succeed if the current working directory is
256 -- writable. If the current working directory is not writable, then
257 -- Invalid_FD is returned for the file descriptor and null for the Name.
258 -- There is no race condition problem between processes trying to create
259 -- temp files at the same time in the same directory.
261 procedure Create_Temp_Output_File
262 (FD : out File_Descriptor;
263 Name : out String_Access);
264 -- Create and open for writing a temporary file in the current working
265 -- directory suitable to redirect standard output. The name of the file and
266 -- the File Descriptor are returned. It is the responsibility of the caller
267 -- to deallocate the access value returned in Name.
269 -- The file is opened in text mode
271 -- This procedure will always succeed if the current working directory is
272 -- writable. If the current working directory is not writable, then
273 -- Invalid_FD is returned for the file descriptor and null for the Name.
274 -- There is no race condition problem between processes trying to create
275 -- temp files at the same time in the same directory.
277 procedure Close (FD : File_Descriptor; Status : out Boolean);
278 -- Close file referenced by FD. Status is False if the underlying service
279 -- failed. Reasons for failure include: disk full, disk quotas exceeded
280 -- and invalid file descriptor (the file may have been closed twice).
282 procedure Close (FD : File_Descriptor);
283 -- Close file referenced by FD. This form is used when the caller wants to
284 -- ignore any possible error (see above for error cases).
286 procedure Set_Close_On_Exec
287 (FD : File_Descriptor;
288 Close_On_Exec : Boolean;
289 Status : out Boolean);
290 -- When Close_On_Exec is True, mark FD to be closed automatically when new
291 -- program is executed by the calling process (i.e. prevent FD from being
292 -- inherited by child processes). When Close_On_Exec is False, mark FD to
293 -- not be closed on exec (i.e. allow it to be inherited). Status is False
294 -- if the operation could not be performed.
296 procedure Delete_File (Name : String; Success : out Boolean);
297 -- Deletes file. Success is set True or False indicating if the delete is
300 procedure Rename_File
303 Success : out Boolean);
304 -- Rename a file. Success is set True or False indicating if the rename is
305 -- successful or not.
307 -- The following defines the mode for the Copy_File procedure below. Note
308 -- that "time stamps and other file attributes" in the descriptions below
309 -- refers to the creation and last modification times, and also the file
310 -- access (read/write/execute) status flags.
314 -- Copy the file. It is an error if the target file already exists. The
315 -- time stamps and other file attributes are preserved in the copy.
318 -- If the target file exists, the file is replaced otherwise the file
319 -- is just copied. The time stamps and other file attributes are
320 -- preserved in the copy.
323 -- If the target file exists, the contents of the source file is
324 -- appended at the end. Otherwise the source file is just copied. The
325 -- time stamps and other file attributes are preserved if the
326 -- destination file does not exist.
330 -- Copy time stamps from source file to target file. All other
331 -- attributes are set to normal default values for file creation.
334 -- All attributes are copied from the source file to the target file.
335 -- This includes the timestamps, and for example also includes
336 -- read/write/execute attributes in Unix systems.
339 -- No attributes are copied. All attributes including the time stamp
340 -- values are set to normal default values for file creation.
342 -- Note: The default is Time_Stamps, which corresponds to the normal
343 -- default on Windows style systems. Full corresponds to the typical
344 -- effect of "cp -p" on Unix systems, and None corresponds to the typical
345 -- effect of "cp" on Unix systems.
347 -- Note: Time_Stamps and Full are not supported on VMS and VxWorks 5
352 Success : out Boolean;
353 Mode : Copy_Mode := Copy;
354 Preserve : Attribute := Time_Stamps);
355 -- Copy a file. Name must designate a single file (no wild cards allowed).
356 -- Pathname can be a filename or directory name. In the latter case Name
357 -- is copied into the directory preserving the same file name. Mode
358 -- defines the kind of copy, see above with the default being a normal
359 -- copy in which the target file must not already exist. Success is set to
360 -- True or False indicating if the copy is successful (depending on the
363 -- Note: this procedure is only supported to a very limited extent on VMS.
364 -- The only supported mode is Overwrite, and the only supported value for
365 -- Preserve is None, resulting in the default action which for Overwrite
366 -- is to leave attributes unchanged. Furthermore, the copy only works for
367 -- simple text files.
369 procedure Copy_Time_Stamps (Source, Dest : String; Success : out Boolean);
370 -- Copy Source file time stamps (last modification and last access time
371 -- stamps) to Dest file. Source and Dest must be valid filenames,
372 -- furthermore Dest must be writable. Success will be set to True if the
373 -- operation was successful and False otherwise.
375 -- Note: this procedure is not supported on VMS and VxWorks 5. On these
376 -- platforms, Success is always set to False.
379 (FD : File_Descriptor;
381 N : Integer) return Integer;
382 -- Read N bytes to address A from file referenced by FD. Returned value is
383 -- count of bytes actually read, which can be less than N at EOF.
386 (FD : File_Descriptor;
388 N : Integer) return Integer;
389 -- Write N bytes from address A to file referenced by FD. The returned
390 -- value is the number of bytes written, which can be less than N if a
391 -- disk full condition was detected.
393 Seek_Cur : constant := 1;
394 Seek_End : constant := 2;
395 Seek_Set : constant := 0;
396 -- Used to indicate origin for Lseek call
399 (FD : File_Descriptor;
400 offset : Long_Integer;
402 pragma Import (C, Lseek, "__gnat_lseek");
403 -- Sets the current file pointer to the indicated offset value, relative
404 -- to the current position (origin = SEEK_CUR), end of file (origin =
405 -- SEEK_END), or start of file (origin = SEEK_SET).
407 function File_Length (FD : File_Descriptor) return Long_Integer;
408 pragma Import (C, File_Length, "__gnat_file_length");
409 -- Get length of file from file descriptor FD
411 function File_Time_Stamp (Name : String) return OS_Time;
412 -- Given the name of a file or directory, Name, obtains and returns the
413 -- time stamp. This function can be used for an unopened file. Returns
414 -- Invalid_Time is Name doesn't correspond to an existing file.
416 function File_Time_Stamp (FD : File_Descriptor) return OS_Time;
417 -- Get time stamp of file from file descriptor FD Returns Invalid_Time is
418 -- FD doesn't correspond to an existing file.
420 function Normalize_Pathname
422 Directory : String := "";
423 Resolve_Links : Boolean := True;
424 Case_Sensitive : Boolean := True) return String;
425 -- Returns a file name as an absolute path name, resolving all relative
426 -- directories, and symbolic links. The parameter Directory is a fully
427 -- resolved path name for a directory, or the empty string (the default).
428 -- Name is the name of a file, which is either relative to the given
429 -- directory name, if Directory is non-null, or to the current working
430 -- directory if Directory is null. The result returned is the normalized
431 -- name of the file. For most cases, if two file names designate the same
432 -- file through different paths, Normalize_Pathname will return the same
433 -- canonical name in both cases. However, there are cases when this is not
434 -- true; for example, this is not true in Unix for two hard links
435 -- designating the same file.
437 -- On Windows, the returned path will start with a drive letter except
438 -- when Directory is not empty and does not include a drive letter. If
439 -- Directory is empty (the default) and Name is a relative path or an
440 -- absolute path without drive letter, the letter of the current drive
441 -- will start the returned path. If Case_Sensitive is True (the default),
442 -- then this drive letter will be forced to upper case ("C:\...").
444 -- If Resolve_Links is set to True, then the symbolic links, on systems
445 -- that support them, will be fully converted to the name of the file or
446 -- directory pointed to. This is slightly less efficient, since it
447 -- requires system calls.
449 -- If Name cannot be resolved or is null on entry (for example if there is
450 -- symbolic link circularity, e.g. A is a symbolic link for B, and B is a
451 -- symbolic link for A), then Normalize_Pathname returns an empty string.
453 -- In VMS, if Name follows the VMS syntax file specification, it is first
454 -- converted into Unix syntax. If the conversion fails, Normalize_Pathname
455 -- returns an empty string.
457 -- For case-sensitive file systems, the value of Case_Sensitive parameter
458 -- is ignored. For file systems that are not case-sensitive, such as
459 -- Windows and OpenVMS, if this parameter is set to False, then the file
460 -- and directory names are folded to lower case. This allows checking
461 -- whether two files are the same by applying this function to their names
462 -- and comparing the results. If Case_Sensitive is set to True, this
463 -- function does not change the casing of file and directory names.
465 function Is_Absolute_Path (Name : String) return Boolean;
466 -- Returns True if Name is an absolute path name, i.e. it designates a
467 -- file or directory absolutely rather than relative to another directory.
469 function Is_Regular_File (Name : String) return Boolean;
470 -- Determines if the given string, Name, is the name of an existing
471 -- regular file. Returns True if so, False otherwise. Name may be an
472 -- absolute path name or a relative path name, including a simple file
473 -- name. If it is a relative path name, it is relative to the current
474 -- working directory.
476 function Is_Directory (Name : String) return Boolean;
477 -- Determines if the given string, Name, is the name of a directory.
478 -- Returns True if so, False otherwise. Name may be an absolute path
479 -- name or a relative path name, including a simple file name. If it is
480 -- a relative path name, it is relative to the current working directory.
482 function Is_Readable_File (Name : String) return Boolean;
483 -- Determines if the given string, Name, is the name of an existing file
484 -- that is readable. Returns True if so, False otherwise. Note that this
485 -- function simply interrogates the file attributes (e.g. using the C
486 -- function stat), so it does not indicate a situation in which a file may
487 -- not actually be readable due to some other process having exclusive
490 function Is_Executable_File (Name : String) return Boolean;
491 -- Determines if the given string, Name, is the name of an existing file
492 -- that is executable. Returns True if so, False otherwise. Note that this
493 -- function simply interrogates the file attributes (e.g. using the C
494 -- function stat), so it does not indicate a situation in which a file may
495 -- not actually be readable due to some other process having exclusive
498 function Is_Writable_File (Name : String) return Boolean;
499 -- Determines if the given string, Name, is the name of an existing file
500 -- that is writable. Returns True if so, False otherwise. Note that this
501 -- function simply interrogates the file attributes (e.g. using the C
502 -- function stat), so it does not indicate a situation in which a file may
503 -- not actually be writeable due to some other process having exclusive
506 function Is_Symbolic_Link (Name : String) return Boolean;
507 -- Determines if the given string, Name, is the path of a symbolic link on
508 -- systems that support it. Returns True if so, False if the path is not a
509 -- symbolic link or if the system does not support symbolic links.
511 -- A symbolic link is an indirect pointer to a file; its directory entry
512 -- contains the name of the file to which it is linked. Symbolic links may
513 -- span file systems and may refer to directories.
515 procedure Set_Writable (Name : String);
516 -- Change permissions on the named file to make it writable for its owner
518 procedure Set_Non_Writable (Name : String);
519 -- Change permissions on the named file to make it non-writable for its
520 -- owner. The readable and executable permissions are not modified.
522 procedure Set_Read_Only (Name : String) renames Set_Non_Writable;
523 -- This renaming is provided for backwards compatibility with previous
524 -- versions. The use of Set_Non_Writable is preferred (clearer name).
526 procedure Set_Executable (Name : String);
527 -- Change permissions on the named file to make it executable for its owner
529 procedure Set_Readable (Name : String);
530 -- Change permissions on the named file to make it readable for its
533 procedure Set_Non_Readable (Name : String);
534 -- Change permissions on the named file to make it non-readable for
535 -- its owner. The writable and executable permissions are not
538 function Locate_Exec_On_Path
539 (Exec_Name : String) return String_Access;
540 -- Try to locate an executable whose name is given by Exec_Name in the
541 -- directories listed in the environment Path. If the Exec_Name does not
542 -- have the executable suffix, it will be appended before the search.
543 -- Otherwise works like Locate_Regular_File below. If the executable is
544 -- not found, null is returned.
546 -- Note that this function allocates memory for the returned value. This
547 -- memory needs to be deallocated after use.
549 function Locate_Regular_File
551 Path : String) return String_Access;
552 -- Try to locate a regular file whose name is given by File_Name in the
553 -- directories listed in Path. If a file is found, its full pathname is
554 -- returned; otherwise, a null pointer is returned. If the File_Name given
555 -- is an absolute pathname, then Locate_Regular_File just checks that the
556 -- file exists and is a regular file. Otherwise, if the File_Name given
557 -- includes directory information, Locate_Regular_File first checks if the
558 -- file exists relative to the current directory. If it does not, or if
559 -- the File_Name given is a simple file name, the Path argument is parsed
560 -- according to OS conventions, and for each directory in the Path a check
561 -- is made if File_Name is a relative pathname of a regular file from that
564 -- Note that this function allocates some memory for the returned value.
565 -- This memory needs to be deallocated after use.
567 function Get_Debuggable_Suffix return String_Access;
568 -- Return the debuggable suffix convention. Usually this is the same as
569 -- the convention for Get_Executable_Suffix. The result is allocated on
570 -- the heap and should be freed after use to avoid storage leaks.
572 function Get_Target_Debuggable_Suffix return String_Access;
573 -- Return the target debuggable suffix convention. Usually this is the same
574 -- as the convention for Get_Executable_Suffix. The result is allocated on
575 -- the heap and should be freed after use to avoid storage leaks.
577 function Get_Executable_Suffix return String_Access;
578 -- Return the executable suffix convention. The result is allocated on the
579 -- heap and should be freed after use to avoid storage leaks.
581 function Get_Object_Suffix return String_Access;
582 -- Return the object suffix convention. The result is allocated on the heap
583 -- and should be freed after use to avoid storage leaks.
585 function Get_Target_Executable_Suffix return String_Access;
586 -- Return the target executable suffix convention. The result is allocated
587 -- on the heap and should be freed after use to avoid storage leaks.
589 function Get_Target_Object_Suffix return String_Access;
590 -- Return the target object suffix convention. The result is allocated on
591 -- the heap and should be freed after use to avoid storage leaks.
593 -- The following section contains low-level routines using addresses to
594 -- pass file name and executable name. In each routine the name must be
595 -- Nul-Terminated. For complete documentation refer to the equivalent
596 -- routine (using String in place of C_File_Name) defined above.
598 subtype C_File_Name is System.Address;
599 -- This subtype is used to document that a parameter is the address of a
600 -- null-terminated string containing the name of a file.
602 -- All the following functions need comments ???
606 Fmode : Mode) return File_Descriptor;
608 function Open_Read_Write
610 Fmode : Mode) return File_Descriptor;
614 Fmode : Mode) return File_Descriptor;
616 function Create_New_File
618 Fmode : Mode) return File_Descriptor;
620 procedure Delete_File (Name : C_File_Name; Success : out Boolean);
622 procedure Rename_File
623 (Old_Name : C_File_Name;
624 New_Name : C_File_Name;
625 Success : out Boolean);
629 Pathname : C_File_Name;
630 Success : out Boolean;
631 Mode : Copy_Mode := Copy;
632 Preserve : Attribute := Time_Stamps);
634 procedure Copy_Time_Stamps
635 (Source, Dest : C_File_Name;
636 Success : out Boolean);
638 function File_Time_Stamp (Name : C_File_Name) return OS_Time;
639 -- Returns Invalid_Time is Name doesn't correspond to an existing file
641 function Is_Regular_File (Name : C_File_Name) return Boolean;
642 function Is_Directory (Name : C_File_Name) return Boolean;
643 function Is_Readable_File (Name : C_File_Name) return Boolean;
644 function Is_Executable_File (Name : C_File_Name) return Boolean;
645 function Is_Writable_File (Name : C_File_Name) return Boolean;
646 function Is_Symbolic_Link (Name : C_File_Name) return Boolean;
648 function Locate_Regular_File
649 (File_Name : C_File_Name;
650 Path : C_File_Name) return String_Access;
656 subtype Argument_List is String_List;
657 -- Type used for argument list in call to Spawn. The lower bound of the
658 -- array should be 1, and the length of the array indicates the number of
661 subtype Argument_List_Access is String_List_Access;
662 -- Type used to return Argument_List without dragging in secondary stack.
663 -- Note that there is a Free procedure declared for this subtype which
664 -- frees the array and all referenced strings.
666 procedure Normalize_Arguments (Args : in out Argument_List);
667 -- Normalize all arguments in the list. This ensure that the argument list
668 -- is compatible with the running OS and will works fine with Spawn and
669 -- Non_Blocking_Spawn for example. If Normalize_Arguments is called twice
670 -- on the same list it will do nothing the second time. Note that Spawn
671 -- and Non_Blocking_Spawn call Normalize_Arguments automatically, but
672 -- since there is a guarantee that a second call does nothing, this
673 -- internal call will have no effect if Normalize_Arguments is called
674 -- before calling Spawn. The call to Normalize_Arguments assumes that the
675 -- individual referenced arguments in Argument_List are on the heap, and
676 -- may free them and reallocate if they are modified.
679 (Program_Name : String;
680 Args : Argument_List;
681 Success : out Boolean);
682 -- This procedure spawns a program with a given list of arguments. The
683 -- first parameter of is the name of the executable. The second parameter
684 -- contains the arguments to be passed to this program. Success is False
685 -- if the named program could not be spawned or its execution completed
686 -- unsuccessfully. Note that the caller will be blocked until the
687 -- execution of the spawned program is complete. For maximum portability,
688 -- use a full path name for the Program_Name argument. On some systems
689 -- (notably Unix systems) a simple file name may also work (if the
690 -- executable can be located in the path).
692 -- Spawning processes from tasking programs is not recommended. See
693 -- "NOTE: Spawn in tasking programs" below.
695 -- Note: Arguments in Args that contain spaces and/or quotes such as
696 -- "--GCC=gcc -v" or "--GCC=""gcc -v""" are not portable across all
697 -- operating systems, and would not have the desired effect if they were
698 -- passed directly to the operating system. To avoid this problem, Spawn
699 -- makes an internal call to Normalize_Arguments, which ensures that such
700 -- arguments are modified in a manner that ensures that the desired effect
701 -- is obtained on all operating systems. The caller may call
702 -- Normalize_Arguments explicitly before the call (e.g. to print out the
703 -- exact form of arguments passed to the operating system). In this case
704 -- the guarantee a second call to Normalize_Arguments has no effect
705 -- ensures that the internal call will not affect the result. Note that
706 -- the implicit call to Normalize_Arguments may free and reallocate some
707 -- of the individual arguments.
709 -- This function will always set Success to False under VxWorks and other
710 -- similar operating systems which have no notion of the concept of
711 -- dynamically executable file. Otherwise Success is set True if the exit
712 -- status of the spawned process is zero.
715 (Program_Name : String;
716 Args : Argument_List) return Integer;
717 -- Similar to the above procedure, but returns the actual status returned
718 -- by the operating system, or -1 under VxWorks and any other similar
719 -- operating systems which have no notion of separately spawnable programs.
721 -- Spawning processes from tasking programs is not recommended. See
722 -- "NOTE: Spawn in tasking programs" below.
725 (Program_Name : String;
726 Args : Argument_List;
727 Output_File_Descriptor : File_Descriptor;
728 Return_Code : out Integer;
729 Err_To_Out : Boolean := True);
730 -- Similar to the procedure above, but redirects the output to the file
731 -- designated by Output_File_Descriptor. If Err_To_Out is True, then the
732 -- Standard Error output is also redirected.
733 -- Return_Code is set to the status code returned by the operating system
735 -- Spawning processes from tasking programs is not recommended. See
736 -- "NOTE: Spawn in tasking programs" below.
739 (Program_Name : String;
740 Args : Argument_List;
741 Output_File : String;
742 Success : out Boolean;
743 Return_Code : out Integer;
744 Err_To_Out : Boolean := True);
745 -- Similar to the procedure above, but saves the output of the command to
746 -- a file with the name Output_File.
748 -- Success is set to True if the command is executed and its output
749 -- successfully written to the file. If Success is True, then Return_Code
750 -- will be set to the status code returned by the operating system.
751 -- Otherwise, Return_Code is undefined.
753 -- Spawning processes from tasking programs is not recommended. See
754 -- "NOTE: Spawn in tasking programs" below.
756 type Process_Id is private;
757 -- A private type used to identify a process activated by the following
758 -- non-blocking calls. The only meaningful operation on this type is a
759 -- comparison for equality.
761 Invalid_Pid : constant Process_Id;
762 -- A special value used to indicate errors, as described below
764 function Pid_To_Integer (Pid : Process_Id) return Integer;
765 -- Convert a process id to an Integer. Useful for writing hash functions
766 -- for type Process_Id or to compare two Process_Id (e.g. for sorting).
768 function Non_Blocking_Spawn
769 (Program_Name : String;
770 Args : Argument_List) return Process_Id;
771 -- This is a non blocking call. The Process_Id of the spawned process is
772 -- returned. Parameters are to be used as in Spawn. If Invalid_Pid is
773 -- returned the program could not be spawned.
775 -- Spawning processes from tasking programs is not recommended. See
776 -- "NOTE: Spawn in tasking programs" below.
778 -- This function will always return Invalid_Pid under VxWorks, since there
779 -- is no notion of executables under this OS.
781 function Non_Blocking_Spawn
782 (Program_Name : String;
783 Args : Argument_List;
784 Output_File_Descriptor : File_Descriptor;
785 Err_To_Out : Boolean := True) return Process_Id;
786 -- Similar to the procedure above, but redirects the output to the file
787 -- designated by Output_File_Descriptor. If Err_To_Out is True, then the
788 -- Standard Error output is also redirected. Invalid_Pid is returned
789 -- if the program could not be spawned successfully.
791 -- Spawning processes from tasking programs is not recommended. See
792 -- "NOTE: Spawn in tasking programs" below.
794 -- This function will always return Invalid_Pid under VxWorks, since there
795 -- is no notion of executables under this OS.
797 function Non_Blocking_Spawn
798 (Program_Name : String;
799 Args : Argument_List;
800 Output_File : String;
801 Err_To_Out : Boolean := True) return Process_Id;
802 -- Similar to the procedure above, but saves the output of the command to
803 -- a file with the name Output_File.
805 -- Success is set to True if the command is executed and its output
806 -- successfully written to the file. Invalid_Pid is returned if the output
807 -- file could not be created or if the program could not be spawned
810 -- Spawning processes from tasking programs is not recommended. See
811 -- "NOTE: Spawn in tasking programs" below.
813 -- This function will always return Invalid_Pid under VxWorks, since there
814 -- is no notion of executables under this OS.
816 procedure Wait_Process (Pid : out Process_Id; Success : out Boolean);
817 -- Wait for the completion of any of the processes created by previous
818 -- calls to Non_Blocking_Spawn. The caller will be suspended until one of
819 -- these processes terminates (normally or abnormally). If any of these
820 -- subprocesses terminates prior to the call to Wait_Process (and has not
821 -- been returned by a previous call to Wait_Process), then the call to
822 -- Wait_Process is immediate. Pid identifies the process that has
823 -- terminated (matching the value returned from Non_Blocking_Spawn).
824 -- Success is set to True if this sub-process terminated successfully. If
825 -- Pid = Invalid_Pid, there were no subprocesses left to wait on.
827 -- This function will always set success to False under VxWorks, since
828 -- there is no notion of executables under this OS.
830 function Argument_String_To_List
831 (Arg_String : String) return Argument_List_Access;
832 -- Take a string that is a program and its arguments and parse it into an
833 -- Argument_List. Note that the result is allocated on the heap, and must
834 -- be freed by the programmer (when it is no longer needed) to avoid
837 -------------------------------------
838 -- NOTE: Spawn in Tasking Programs --
839 -------------------------------------
841 -- Spawning processes in tasking programs using the above Spawn and
842 -- Non_Blocking_Spawn subprograms is not recommended, because there are
843 -- subtle interactions between creating a process and signals/locks that
844 -- can cause trouble. These issues are not specific to Ada; they depend
845 -- primarily on the operating system.
847 -- If you need to spawn processes in a tasking program, you will need to
848 -- understand the semantics of your operating system, and you are likely to
849 -- write non-portable code, because operating systems differ in this area.
851 -- The Spawn and Non_Blocking_Spawn subprograms call the following
852 -- operating system functions:
854 -- On Windows: spawnvp (blocking) or CreateProcess (non-blocking)
856 -- On Solaris: fork1, followed in the child process by execv
858 -- On other Unix-like systems, and on VMS: fork, followed in the child
861 -- On vxworks, nucleus, and RTX, spawning of processes is not supported
863 -- For details, look at the functions __gnat_portable_spawn and
864 -- __gnat_portable_no_block_spawn in adaint.c.
866 -- You should read the operating-system-specific documentation for the
867 -- above functions, paying special attention to subtle interactions with
868 -- threading, signals, locks, and file descriptors. Most of the issues are
869 -- related to the fact that on Unix, there is a window of time between fork
870 -- and execv; Windows does not have this problem, because spawning is done
871 -- in a single operation.
873 -- On Posix-compliant systems, such as Linux, fork duplicates just the
874 -- calling thread. (On Solaris, fork1 is the Posix-compliant version of
877 -- You should avoid using signals while spawning. This includes signals
878 -- used internally by the Ada run-time system, such as timer signals used
879 -- to implement delay statements.
881 -- It is best to spawn any subprocesses very early, before the parent
882 -- process creates tasks, locks, or installs signal handlers. Certainly
883 -- avoid doing simultaneous spawns from multiple threads of the same
886 -- There is no problem spawning a subprocess that uses tasking: the
887 -- problems are caused only by tasking in the parent.
889 -- If the parent is using tasking, and needs to spawn subprocesses at
890 -- arbitrary times, one technique is for the parent to spawn (very early)
891 -- a particular spawn-manager subprocess whose job is to spawn other
892 -- processes. The spawn-manager must avoid tasking. The parent sends
893 -- messages to the spawn-manager requesting it to spawn processes, using
894 -- whatever inter-process communication mechanism you like, such as
897 -- In short, mixing spawning of subprocesses with tasking is a tricky
898 -- business, and should be avoided if possible, but if it is necessary,
899 -- the above guidelines should be followed, and you should beware of
900 -- portability problems.
906 function Getenv (Name : String) return String_Access;
907 -- Get the value of the environment variable. Returns an access to the
908 -- empty string if the environment variable does not exist or has an
909 -- explicit null value (in some operating systems these are distinct
910 -- cases, in others they are not; this interface abstracts away that
911 -- difference. The argument is allocated on the heap (even in the null
912 -- case), and needs to be freed explicitly when no longer needed to avoid
915 procedure Setenv (Name : String; Value : String);
916 -- Set the value of the environment variable Name to Value. This call
917 -- modifies the current environment, but does not modify the parent
918 -- process environment. After a call to Setenv, Getenv (Name) will always
919 -- return a String_Access referencing the same String as Value. This is
920 -- true also for the null string case (the actual effect may be to either
921 -- set an explicit null as the value, or to remove the entry, this is
922 -- operating system dependent). Note that any following calls to Spawn
923 -- will pass an environment to the spawned process that includes the
924 -- changes made by Setenv calls. This procedure is not available on VMS.
926 procedure OS_Exit (Status : Integer);
927 pragma No_Return (OS_Exit);
929 -- Exit to OS with given status code (program is terminated). Note that
930 -- this is abrupt termination. All tasks are immediately terminated. There
931 -- are no finalization or other Ada-specific cleanup actions performed. On
932 -- systems with atexit handlers (such as Unix and Windows), atexit handlers
935 type OS_Exit_Subprogram is access procedure (Status : Integer);
937 procedure OS_Exit_Default (Status : Integer);
938 pragma No_Return (OS_Exit_Default);
939 -- Default implementation of procedure OS_Exit
941 OS_Exit_Ptr : OS_Exit_Subprogram := OS_Exit_Default'Access;
942 -- OS_Exit is implemented through this access value. It it then possible to
943 -- change the implementation of OS_Exit by redirecting OS_Exit_Ptr to an
944 -- other implementation.
947 pragma Import (C, OS_Abort, "abort");
948 pragma No_Return (OS_Abort);
949 -- Exit to OS signalling an abort (traceback or other appropriate
950 -- diagnostic information should be given if possible, or entry made to
951 -- the debugger if that is possible).
953 function Errno return Integer;
954 pragma Import (C, Errno, "__get_errno");
955 -- Return the task-safe last error number
957 procedure Set_Errno (Errno : Integer);
958 pragma Import (C, Set_Errno, "__set_errno");
959 -- Set the task-safe error number
961 Directory_Separator : constant Character;
962 -- The character that is used to separate parts of a pathname
964 Path_Separator : constant Character;
965 -- The character to separate paths in an environment variable value
968 pragma Import (C, Path_Separator, "__gnat_path_separator");
969 pragma Import (C, Directory_Separator, "__gnat_dir_separator");
970 pragma Import (C, Current_Time, "__gnat_current_time");
973 range -(2 ** (Standard'Address_Size - Integer'(1))) ..
974 +(2 ** (Standard'Address_Size - Integer'(1)) - 1);
975 -- Type used for timestamps in the compiler. This type is used to hold
976 -- time stamps, but may have a different representation than C's time_t.
977 -- This type needs to match the declaration of OS_Time in adaint.h.
979 -- Add pragma Inline statements for comparison operations on OS_Time. It
980 -- would actually be nice to use pragma Import (Intrinsic) here, but this
981 -- was not properly supported till GNAT 3.15a, so that would cause
982 -- bootstrap path problems. To be changed later ???
984 Invalid_Time : constant OS_Time := -1;
985 -- This value should match the return value from __gnat_file_time_*
989 pragma Inline ("<=");
990 pragma Inline (">=");
992 type Process_Id is new Integer;
993 Invalid_Pid : constant Process_Id := -1;
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