From cf255dd3a4f01da5e88c6da3738e7745ad8b9594 Mon Sep 17 00:00:00 2001 From: Maxime Devos Date: Tue, 16 Nov 2021 11:06:35 +0000 Subject: =?UTF-8?q?Define=20a=20Scheme=20binding=20to=20=E2=80=98fstatat?= =?UTF-8?q?=E2=80=99=20when=20available.?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * configure.ac: Detect if ‘fstatat’ is defined. * libguile/filesys.c (scm_statat): Define a Scheme binding to ‘fstatat’. * libguile/filesys.h (scm_statat): Make it part of the C API. * doc/ref/posix.texi (File System): Document it. * libguile/syscalls.h (fstatat_or_fstatat64): Choose between ‘fstatat’ and ‘fstatat64’. Signed-off-by: Ludovic Courtès --- configure.ac | 4 +-- doc/ref/posix.texi | 8 +++++ libguile/filesys.c | 39 +++++++++++++++++++++ libguile/filesys.h | 1 + libguile/syscalls.h | 1 + test-suite/tests/filesys.test | 80 +++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 131 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index 89f89ae8d..7aa5a46d7 100644 --- a/configure.ac +++ b/configure.ac @@ -509,7 +509,7 @@ AC_CHECK_HEADERS([crt_externs.h]) # isblank - available as a GNU extension or in C99 # _NSGetEnviron - Darwin specific # strcoll_l, newlocale, uselocale, utimensat, futimens, fchmodat, -# unlinkat, fchownat - POSIX.1-2008 +# unlinkat, fchownat, fstatat - POSIX.1-2008 # strtol_l - non-POSIX, found in glibc # fork - unavailable on Windows # sched_getaffinity, sched_setaffinity - GNU extensions (glibc) @@ -527,7 +527,7 @@ AC_CHECK_FUNCS([DINFINITY DQNAN cexp chsize clog clog10 ctermid \ getgrent kill getppid getpgrp fork setitimer getitimer strchr strcmp \ index bcopy rindex truncate isblank _NSGetEnviron \ strcoll_l strtod_l strtol_l newlocale uselocale utimensat \ - futimens sched_getaffinity sched_setaffinity sendfile pipe2]) + fstatat futimens sched_getaffinity sched_setaffinity sendfile pipe2]) # The newlib C library uses _NL_ prefixed locale langinfo constants. AC_CHECK_DECLS([_NL_NUMERIC_GROUPING], [], [], [[#include ]]) diff --git a/doc/ref/posix.texi b/doc/ref/posix.texi index 112c25d30..601c33747 100644 --- a/doc/ref/posix.texi +++ b/doc/ref/posix.texi @@ -773,6 +773,14 @@ it will return information about a symbolic link itself, not the file it points to. @var{path} must be a string. @end deffn +@deffn {Scheme Procedure} statat dir filename [flags] +@deffnx {C Function} scm_statat dir filename flags +Like @code{stat}, but resolve @var{filename} relative to the directory +referred to by the file port @var{dir} instead. The optional argument +@var{flags} argument can be @code{AT_SYMLINK_NOFOLLOW}, in which case +@var{filename} will not be dereferenced even if it is a symbolic link. +@end deffn + @deffn {Scheme Procedure} readlink path @deffnx {C Function} scm_readlink (path) Return the value of the symbolic link named by @var{path} (a string, or diff --git a/libguile/filesys.c b/libguile/filesys.c index af00a98d4..6fa641d16 100644 --- a/libguile/filesys.c +++ b/libguile/filesys.c @@ -588,6 +588,45 @@ SCM_DEFINE (scm_stat, "stat", 1, 1, 0, } #undef FUNC_NAME +#ifdef HAVE_FSTATAT +SCM_DEFINE (scm_statat, "statat", 2, 1, 0, + (SCM dir, SCM filename, SCM flags), + "Like @code{stat}, but resolve @var{filename} relative to the\n" + "directory referred to by the file port @var{dir} instead.\n\n" + "The optional argument @var{flags} argument can be\n" + "@code{AT_SYMLINK_NOFOLLOW}, in which case @var{filename} will\n" + "not be dereferenced even if it is a symbolic link.") +#define FUNC_NAME s_scm_statat +{ + int rv; + int dir_fdes; + int c_flags; + struct stat_or_stat64 stat_temp; + + 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 (filename, c_filename, + rv = fstatat_or_fstatat64 (dir_fdes, c_filename, + &stat_temp, c_flags)); + scm_remember_upto_here_1 (dir); + if (rv != 0) + { + int en = errno; + SCM_SYSERROR_MSG ("~A: ~S", + scm_list_2 (scm_strerror (scm_from_int (en)), filename), + en); + } + return scm_stat2scm (&stat_temp); +} +#undef FUNC_NAME +#endif /* HAVE_FSTATAT */ + SCM_DEFINE (scm_lstat, "lstat", 1, 0, 0, (SCM str), "Similar to @code{stat}, but does not follow symbolic links, i.e.,\n" diff --git a/libguile/filesys.h b/libguile/filesys.h index 7673c8051..8af0f989a 100644 --- a/libguile/filesys.h +++ b/libguile/filesys.h @@ -48,6 +48,7 @@ SCM_API SCM scm_open (SCM path, SCM flags, SCM mode); SCM_API SCM scm_close (SCM fd_or_port); SCM_API SCM scm_close_fdes (SCM fd); SCM_API SCM scm_stat (SCM object, SCM exception_on_error); +SCM_API SCM scm_statat (SCM dir, SCM filename, SCM flags); 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); diff --git a/libguile/syscalls.h b/libguile/syscalls.h index 30b99c193..37d532e60 100644 --- a/libguile/syscalls.h +++ b/libguile/syscalls.h @@ -65,6 +65,7 @@ # define readdir_r_or_readdir64_r readdir_r #endif #define stat_or_stat64 CHOOSE_LARGEFILE(stat,stat64) +#define fstatat_or_fstatat64 CHOOSE_LARGEFILE(fstatat,fstatat64) #define truncate_or_truncate64 CHOOSE_LARGEFILE(truncate,truncate64) #define scm_from_off_t_or_off64_t CHOOSE_LARGEFILE(scm_from_off_t,scm_from_int64) #define scm_from_ino_t_or_ino64_t CHOOSE_LARGEFILE(scm_from_ulong,scm_from_uint64) diff --git a/test-suite/tests/filesys.test b/test-suite/tests/filesys.test index 33b68e16d..b794b07b3 100644 --- a/test-suite/tests/filesys.test +++ b/test-suite/tests/filesys.test @@ -134,6 +134,86 @@ (close-port port) (eqv? 5 (stat:size st)))))) +(with-test-prefix "statat" + ;; file-exists? from (ice-9 boot) dereferences symbolic links + ;; (a bug?). + (define (file-exists? filename) + (catch 'system-error + (lambda () (lstat filename) #t) + (lambda args + (if (= (system-error-errno args) ENOENT) + ;; For the purposes of the following tests, + ;; it is safe to ignore errors like EPERM, but a correct + ;; implementation would return #t for that error. + #f + (apply throw args))))) + (define (maybe-delete-directory) + (when (file-exists? (test-directory)) + (for-each + (lambda (filename) + (define full-name (in-vicinity (test-directory) filename)) + (when (file-exists? full-name) + (delete-file full-name))) + '("test-file" "test-symlink")) + (rmdir (test-directory)))) + (define (skip-unless-defined . things) + (for-each (lambda (thing) + (unless (defined? thing) + (throw 'unsupported))) + things)) + (maybe-delete-directory) + (mkdir (test-directory)) + (call-with-output-file (in-vicinity (test-directory) "test-file") + (lambda (port) + (display "hello" port))) + + ;; Return #true if the symlink was created, #false otherwise. + (define (maybe-create-symlink) + (if (file-exists? (in-vicinity (test-directory) "test-symlink")) + #t + (false-if-exception + (symlink "test-file" + (in-vicinity (test-directory) "test-symlink"))))) + + (pass-if-equal "regular file" 5 + (skip-unless-defined 'statat) + (call-with-port + (open (test-directory) O_RDONLY) + (lambda (port) + (stat:size (statat port "test-file"))))) + + (pass-if-equal "regular file, AT_SYMLINK_NOFOLLOW" 5 + (skip-unless-defined 'statat 'AT_SYMLINK_NOFOLLOW) + (call-with-port + (open (test-directory) O_RDONLY) + (lambda (port) + (stat:size (statat port "test-file" AT_SYMLINK_NOFOLLOW))))) + + (pass-if-equal "symbolic links are dereferenced" '(regular 5) + ;; Not all systems support symlinks. + (skip-unless-defined 'statat 'symlink) + (unless (maybe-create-symlink) + (throw 'unresolved)) + (call-with-port + (open (test-directory) O_RDONLY) + (lambda (port) + (define result (statat port "test-symlink")) + (list (stat:type result) (stat:size result))))) + + (pass-if-equal "symbolic links are not dereferenced" + `(symlink ,(string-length "test-file")) + ;; Not all systems support symlinks. + (skip-unless-defined 'statat 'symlink) + (unless (maybe-create-symlink) + (throw 'unresolved)) + (call-with-port + (open (test-directory) O_RDONLY) + (lambda (port) + (define result (statat port "test-symlink" AT_SYMLINK_NOFOLLOW)) + (list (stat:type result) (stat:size result))))) + + (maybe-delete-directory)) + (with-test-prefix "sendfile" (let* ((file (search-path %load-path "ice-9/boot-9.scm")) -- cgit v1.2.1