From 3b45185d8f40b5c41abfe15571550ce1a7fd4011 Mon Sep 17 00:00:00 2001 From: Maxime Devos Date: Tue, 16 Nov 2021 11:06:33 +0000 Subject: =?UTF-8?q?Define=20a=20Scheme=20binding=20to=20=E2=80=98unlinkat?= =?UTF-8?q?=E2=80=99=20when=20it=20exists.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ‘unlinkat’ is used for both unlinking regular files and removing empty directories. * configure.ac: Detect if ‘unlinkat’ exists. * doc/ref/posix.texi (File System): Document why there is no ‘rmdirat’ procedure, and document the ‘delete-file-at’ procedure. * libguile/filesys.c (scm_rmdir): Adjust the docstring here as well. (scm_delete_file_at): Define a Scheme binding to ‘unlinkat’. * libguile/filesys.h (scm_delete_file_at): Make ‘scm_delete_file_at’ part of the C API. Signed-off-by: Ludovic Courtès --- configure.ac | 5 ++-- doc/ref/posix.texi | 12 +++++++++ libguile/filesys.c | 32 +++++++++++++++++++++++ libguile/filesys.h | 1 + test-suite/tests/filesys.test | 59 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 107 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index b3aeb6a3c..16786eab7 100644 --- a/configure.ac +++ b/configure.ac @@ -508,7 +508,8 @@ AC_CHECK_HEADERS([crt_externs.h]) # truncate - not in mingw # isblank - available as a GNU extension or in C99 # _NSGetEnviron - Darwin specific -# strcoll_l, newlocale, uselocale, utimensat, futimens, fchmodat - POSIX.1-2008 +# strcoll_l, newlocale, uselocale, utimensat, futimens, fchmodat, +# unlinkat - POSIX.1-2008 # strtol_l - non-POSIX, found in glibc # fork - unavailable on Windows # sched_getaffinity, sched_setaffinity - GNU extensions (glibc) @@ -517,7 +518,7 @@ AC_CHECK_HEADERS([crt_externs.h]) # AC_CHECK_FUNCS([DINFINITY DQNAN cexp chsize clog clog10 ctermid \ fesetround ftime ftruncate fchown fchmod fchdir readlinkat \ - fchmodat symlinkat mkdirat renameat getcwd geteuid getsid \ + fchmodat symlinkat mkdirat renameat unlinkat getcwd geteuid getsid \ gettimeofday getuid getgid gmtime_r ioctl lstat mkdir mkdtemp mknod \ nice readlink rmdir setegid seteuid \ setuid setgid setpgid setsid sigaction siginterrupt stat64 \ diff --git a/doc/ref/posix.texi b/doc/ref/posix.texi index 85da56ca8..7524ba5df 100644 --- a/doc/ref/posix.texi +++ b/doc/ref/posix.texi @@ -852,6 +852,18 @@ Deletes (or ``unlinks'') the file whose path is specified by @var{str}. @end deffn +@findex unlinkat +@deffn {Scheme Procedure} delete-file-at dir str [flags] +@deffnx {C Function} scm_delete_file_at (dir, str, flags) +Like @code{unlink}, but resolve @var{str} relative to the +directory referred to by the file port @var{dir} instead. + +The optional @var{flags} argument can be @code{AT_REMOVEDIR}, +in which case @code{delete-file-at} will act like @code{rmdir} instead +of @code{delete-file}. Why doesn't POSIX have a @code{rmdirat} function +for this instead? No idea! +@end deffn + @deffn {Scheme Procedure} copy-file oldfile newfile @deffnx {C Function} scm_copy_file (oldfile, newfile) Copy the file specified by @var{oldfile} to @var{newfile}. diff --git a/libguile/filesys.c b/libguile/filesys.c index 1ec85d940..ee7fc5bfa 100644 --- a/libguile/filesys.c +++ b/libguile/filesys.c @@ -1456,6 +1456,38 @@ SCM_DEFINE (scm_delete_file, "delete-file", 1, 0, 0, } #undef FUNC_NAME +#ifdef HAVE_UNLINKAT +SCM_DEFINE (scm_delete_file_at, "delete-file-at", 2, 1, 0, + (SCM dir, SCM str, SCM flags), + "Like @code{unlink}, but resolve @var{str} relative to the\n" + "directory referred to by the file port @var{dir} instead.\n\n" + "The optional @var{flags} argument can be @code{AT_REMOVEDIR},\n" + "in which case @code{delete-file-at} will act like @code{rmdir} instead\n" + "of @code{delete-file}. Why doesn't POSIX have a @code{rmdirat} function\n" + "for this instead? No idea!") +#define FUNC_NAME s_scm_delete_file_at +{ + int ans; + int dir_fdes; + int c_flags; + + if (SCM_UNBNDP (flags)) + c_flags = 0; + else + c_flags = scm_to_int (flags); + + SCM_VALIDATE_OPFPORT (SCM_ARG1, dir); + dir_fdes = SCM_FPORT_FDES (dir); + + STRING_SYSCALL (str, c_str, ans = unlinkat (dir_fdes, c_str, c_flags)); + scm_remember_upto_here_1 (dir); + if (ans != 0) + SCM_SYSERROR; + return SCM_UNSPECIFIED; +} +#undef FUNC_NAME +#endif + SCM_DEFINE (scm_access, "access?", 2, 0, 0, (SCM path, SCM how), "Test accessibility of a file under the real UID and GID of the\n" diff --git a/libguile/filesys.h b/libguile/filesys.h index 377a3795e..37d084cd5 100644 --- a/libguile/filesys.h +++ b/libguile/filesys.h @@ -51,6 +51,7 @@ SCM_API SCM scm_link (SCM oldpath, SCM newpath); SCM_API SCM scm_rename (SCM oldname, SCM newname); SCM_API SCM scm_renameat (SCM olddir, SCM oldname, SCM newdir, SCM newname); SCM_API SCM scm_delete_file (SCM str); +SCM_API SCM scm_delete_file_at (SCM dir, SCM str, SCM flags); SCM_API SCM scm_mkdir (SCM path, SCM mode); SCM_API SCM scm_mkdirat (SCM dir, SCM path, SCM mode); SCM_API SCM scm_rmdir (SCM path); diff --git a/test-suite/tests/filesys.test b/test-suite/tests/filesys.test index 204f3414c..33b68e16d 100644 --- a/test-suite/tests/filesys.test +++ b/test-suite/tests/filesys.test @@ -589,3 +589,62 @@ (pass-if-exception "not a string (2)" exception:wrong-type-arg (skip-if-unsupported) (rename-file-at #f "some" #f 'what))) + +(with-test-prefix "delete-file-at" + (define (skip-if-unsupported) + (when (not (and (defined? 'delete-file-at) + (defined? 'AT_REMOVEDIR))) + (throw 'unsupported))) + (define (create-test-file) + (call-with-output-file (test-file) identity)) + (define (create-test-directory) + (mkdir (test-directory))) + (define (delete-test-file) + (when (file-exists? (test-file)) + (delete-file (test-file)))) + (define (delete-test-directory) + (when (file-exists? (test-directory)) + (rmdir (test-directory)))) + + (pass-if-equal "regular file" #f + (skip-if-unsupported) + (create-test-file) + (call-with-port + (open (dirname (test-file)) O_RDONLY) + (lambda (port) + (delete-file-at port (basename (test-file))))) + (file-exists? (test-file))) + (delete-test-file) + + (pass-if-equal "regular file, explicit flags" #f + (skip-if-unsupported) + (create-test-file) + (call-with-port + (open (dirname (test-file)) O_RDONLY) + (lambda (port) + (delete-file-at port (basename (test-file)) 0))) + (file-exists? (test-file))) + (delete-test-file) + + (pass-if-equal "directory, explicit flags" #f + (skip-if-unsupported) + (create-test-directory) + (call-with-port + (open (dirname (test-directory)) O_RDONLY) + (lambda (port) + (delete-file-at port (basename (test-directory)) AT_REMOVEDIR))) + (file-exists? (test-directory))) + (delete-test-directory) + + (pass-if-exception "not a port" exception:wrong-type-arg + (skip-if-unsupported) + (delete-file-at 'bogus "irrelevant")) + + (pass-if-exception "not a file port" exception:wrong-type-arg + (skip-if-unsupported) + (delete-file-at (open-input-string "") "irrelevant")) + + (pass-if-exception "closed port" exception:wrong-type-arg + (skip-if-unsupported) + (delete-file-at (call-with-port (open "." O_RDONLY) identity) + "irrelevant"))) -- cgit v1.2.1