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This extension exposes POSIX functionalities in STklos.
Note that this version is very incomplete and only a few POSIX
functionalities are available for now.
To use this extension you need to include the following
form in your program:
(require "stklos-posix")
(import stklos-posix)
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The functions of this extension may set a special
parameter value when an error occurs. The mechanism used is
described here (see also Error management
for more information). In general a function returns a useful
result (or #t if no useful value is possible) if no
error is detected. When a function detects an error, it returns
#f. The error number is then available through the
posix-errno parameter and a
string describing the error can be built by the
posix-error primitive.
3.1 Directories Functions
(posix-change-directory path) | STklos procedure |
Change the current directory to "path". Return #t in case of sucess. |
(posix-current-directory) | STklos procedure |
Return the current directory if possible. When an error occurs, this function
returns #f. |
(posix-make-directory path) | STklos procedure |
Create a directory with name "path". Return #t in case of sucess. |
(posix-delete-directory path) | STklos procedure |
Delete the directory "path". Return #t in case of sucess. |
3.2 Links and Symbolic Links functions
(posix-make-link old-path new-path) | STklos procedure |
Create a hard link with the filename "new-path" that points to the file named
"old-path". Return #t in case of sucess. |
(posix-delete-link old-path new-path) | STklos procedure |
Create a symbolic link with the filename "new-path" that points to the file named
"old-path". Return #t in case of sucess. |
(posix-file-is-symbolic-link? path) | STklos procedure |
Return #t if "path" designates a symbolic link and #f othewise. |
(posix-read-symbolic-link path) | STklos procedure |
Return a string containing the filename to
which the symbolic link "path" points to. |
3.3 Error management
When an error occurs POSIX sets the errno global variable to a
return code describing the error. This error code is available
from the posix-errno Scheme parameter.
(posix-errno) | STklos procedure |
(posix-errno value)
Return the value of the POSIX errno variable. When a value is
passed to the posix-errno, this value is set to the POSIX errno variable. |
(posix-error) | STklos procedure |
Return a string describing the last POSIX error detected. |
Furthermore, the POSIX extension defines also the following constants for
representing POSIX error numbers.
| posix/e2big | posix/eacces | posix/eaddrinuse |
| posix/eaddrnotavail | posix/eafnosupport | posix/eagain |
| posix/ealready | posix/ebadf | posix/ebadmsg |
| posix/ebusy | posix/ecanceled | posix/echild |
| posix/econnaborted | posix/econnrefused | posix/econnreset |
| posix/edeadlk | posix/edestaddrreq | posix/edom |
| posix/edquot | posix/eexist | posix/efault |
| posix/efbig | posix/ehostunreach | posix/eidrm |
| posix/eilseq | posix/einprogress | posix/eintr |
| posix/einval | posix/eio | posix/eisconn |
| posix/eisdir | posix/eloop | posix/emfile |
| posix/emlink | posix/emsgsize | posix/emultihop |
| posix/enametoolong | posix/enetdlown | posix/enetreset |
| posix/enetunreach | posix/enfile | posix/enobufs |
| posix/enodata | posix/enodev | posix/enoent |
| posix/enoexec | posix/enolck | posix/enolink |
| posix/enomem | posix/enomsg | posix/enoprotoopt |
| posix/enospc | posix/enosr | posix/enostr |
| posix/enosys | posix/enotconn | posix/enotdlir |
| posix/enotempty | posix/enotsock | posix/enotsup |
| posix/enotty | posix/enxio | posix/eopnotsupp |
| posix/eoverflow | posix/eperm | posix/epipe |
| posix/eproto | posix/eprotonosupport | posix/eprototype |
| posix/erange | posix/erofs | posix/espipe |
| posix/esrch | posix/estale | posix/etime |
| posix/etimedout | posix/etxtbsy | posix/ewouldblock |
| posix/exdev |
(posix-file-informations path) | STklos procedure |
Return a keyword list describing the cureent status of file
"path".
(posix-file-informations "/")
⇒ (:dev 770 :ino 2 :mode 16877 :nlink 17 :uid 0 :gid 0
:size 4096 :atime 1115017161 :mtime 1134028671
:ctime 1134028671)
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The following constants are defined to analyse the bits of the
mode component returned by posix-file-informations:
| posix/ifsock | posix/iflnk | posix/ifreg | posix/ifblk |
| posix/ifdir | posix/ifchr | posix/ififo | posix/isuid |
| posix/isgid | posix/isvtx | posix/irwxu | posix/irusr |
| posix/iwusr | posix/ixusr | posix/irwxg | posix/irgrp |
| posix/iwgrp | posix/ixgrp | posix/irwxo | posix/iroth |
| posix/iwoth | posix/ixoth |
(posix-file-permissions path) | STklos procedure |
Return the permissions flag associated to "path" if the file
is accesible. Return #f ostherwise. |
(posix-uid->string uid) | STklos procedure |
Return the login name associated to uid. |
(posix-uid->string logname) | STklos procedure |
Return the uid associated to the logname. |
(posix-gid->string uid) | STklos procedure |
Return the group name associated to gid. |
(posix-uid->string grpname) | STklos procedure |
Return the gid associated to the grpname. |
(posix-user-id) | STklos procedure |
Return the user id of the running process. |
(posix-group-id) | STklos procedure |
Return the group id of the running process. |
(posix-effective-user-id) | STklos procedure |
Return the effective user id of the running process. |
(posix-effective-group-id) | STklos procedure |
Return the effective group id of the running process. |
Here is a simple program using the STklos Posix extension. It
displays some information of the path given as parameter
(require "stklos-posix")
(import stklos-posix)
(define (usage)
(format (current-error-port) "Usage: ~A file\n" (program-name))
(exit 1))
(define (bit-set? bit in)
(= (bit-and bit in) bit))
(define (main args)
(if (not (= (length args) 2))
(usage)
(let ((stat (posix-file-informations (cadr args))))
(if (not stat)
(format (current-error-port) "Return code ~S. Message ~S\n"
(posix-errno) (posix-error))
(let ((mode (key-get stat :mode)))
(format #t "Type of file: ~A\n"
(cond
((bit-set? posix/ifsock mode) "socket")
((bit-set? posix/iflnk mode) "symbolic link")
((bit-set? posix/ifreg mode) "regular file")
((bit-set? posix/ifblk mode) "block device")
((bit-set? posix/ifchr mode) "character device")
((bit-set? posix/ifdir mode) "directory")))
(format #t "Owner: ~A\n"
(posix-uid->string (key-get stat :uid)))
(format #t "Group: ~A\n"
(posix-gid->string (key-get stat :gid))))))))
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