Enable visiting FIFOs as files
* doc/lispref/files.texi (Reading from Files): Document new `if-regular' value of REPLACE. * etc/NEWS: Announce the new value. * lisp/files.el (basic-save-buffer-2): Demote errors saving backup files, since FIFOs cannot be copied. (revert-buffer-insert-file-contents--default-function): Supply `if-regular' instead of t as REPLACE. * src/fileio.c (selinux_enabled_p): New function. (Fcopy_file, Ffile_selinux_context, Fset_file_selinux_context): Call that function to ascertain if SELinux applies to a file. (read_non_regular): Don't assume `emacs_fd_read' always returns int. (Finsert_file_contents): If REPLACE is if-regular and FILENAME is a special non-seekable file, fall back to erasing the buffer before inserting the contents of that file. (syms_of_fileio) <Qif_regular>: New symbol.
This commit is contained in:
Po Lu
parent
594e03526b
commit
3fb2c174d3
4 changed files with 116 additions and 52 deletions
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@ -582,11 +582,12 @@ contents and inserting the whole file, because (1) it preserves some
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marker positions and (2) it puts less data in the undo list.
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It is possible to read a special file (such as a FIFO or an I/O
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device) with @code{insert-file-contents}, as long as @var{replace},
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and @var{visit} and @var{beg} are @code{nil}. However, you should
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normally use an @var{end} argument for these files to avoid inserting
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(potentially) unlimited data into the buffer (for instance, when
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inserting data from @file{/dev/urandom}).
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device) with @code{insert-file-contents}, as long as @var{replace} is
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@code{nil} or @code{if-regular}, and @var{visit} and @var{beg} are
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@code{nil}. However, you should normally use an @var{end} argument
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for these files to avoid inserting (potentially) unlimited data into
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the buffer (for instance, when inserting data from
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@file{/dev/urandom}).
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@end defun
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@defun insert-file-contents-literally filename &optional visit beg end replace
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6
etc/NEWS
6
etc/NEWS
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@ -743,6 +743,12 @@ The compatibility aliases 'x-defined-colors', 'x-color-defined-p',
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See (info "(elisp)Porting Old Advice") for help converting them
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to use `advice-add` or `define-advice instead.
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+++
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** New value 'if-regular' for the REPLACE argument to 'insert-file-contents'.
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It results in 'insert-file-contents' erasing the buffer instead of
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preserving markers if the file being inserted is not a regular file,
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rather than signaling an error.
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+++
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** New variable 'current-key-remap-sequence'.
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It is bound to the key sequence that caused a call to a function bound
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@ -5871,8 +5871,10 @@ Before and after saving the buffer, this function runs
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buffer-file-name)))
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(setq tempsetmodes t)
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(error "Attempt to save to a file that you aren't allowed to write"))))))
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(or buffer-backed-up
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(setq setmodes (backup-buffer)))
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(with-demoted-errors
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"Backing up buffer: %s"
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(or buffer-backed-up
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(setq setmodes (backup-buffer))))
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(let* ((dir (file-name-directory buffer-file-name))
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(dir-writable (file-writable-p dir)))
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(if (or (and file-precious-flag dir-writable)
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@ -6894,9 +6896,9 @@ an auto-save file."
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(if revert-buffer-preserve-modes
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(let ((buffer-file-format buffer-file-format))
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(insert-file-contents file-name (not auto-save-p)
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nil nil t))
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nil nil 'if-regular))
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(insert-file-contents file-name (not auto-save-p)
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nil nil t))))))
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nil nil 'if-regular))))))
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(defvar revert-buffer-with-fine-grain-max-seconds 2.0
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"Maximum time that `revert-buffer-with-fine-grain' should use.
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141
src/fileio.c
141
src/fileio.c
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@ -200,6 +200,25 @@ check_vfs_filename (Lisp_Object encoded, const char *reason)
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#endif /* defined HAVE_ANDROID && !defined ANDROID_STUBIFY */
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}
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#ifdef HAVE_LIBSELINUX
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/* Return whether SELinux is enabled and pertinent to FILE. Provide
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for cases where FILE is or is a constitutent of a special
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directory, such as /assets or /content on Android. */
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static bool
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selinux_enabled_p (const char *file)
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{
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return (is_selinux_enabled ()
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#if defined HAVE_ANDROID && !defined ANDROID_STUBIFY
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&& !android_is_special_directory (file, "/assets")
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&& !android_is_special_directory (file, "/content")
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#endif /* defined HAVE_ANDROID && !defined ANDROID_STUBIFY */
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);
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}
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#endif /* HAVE_LIBSELINUX */
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/* Test whether FILE is accessible for AMODE.
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Return true if successful, false (setting errno) otherwise. */
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@ -2311,7 +2330,7 @@ permissions. */)
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if (!NILP (preserve_permissions))
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{
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#if HAVE_LIBSELINUX
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if (is_selinux_enabled ()
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if (selinux_enabled_p (SSDATA (encoded_file))
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&& emacs_fd_to_int (ifd) != -1)
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{
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conlength = fgetfilecon (emacs_fd_to_int (ifd),
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@ -2319,7 +2338,7 @@ permissions. */)
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if (conlength == -1)
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report_file_error ("Doing fgetfilecon", file);
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}
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#endif
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#endif /* HAVE_LIBSELINUX */
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}
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/* We can copy only regular files. */
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@ -3353,6 +3372,7 @@ or if SELinux is disabled, or if Emacs lacks SELinux support. */)
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{
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Lisp_Object user = Qnil, role = Qnil, type = Qnil, range = Qnil;
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Lisp_Object absname = expand_and_dir_to_file (filename);
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const char *file;
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/* If the file name has special constructs in it,
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call the corresponding file name handler. */
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@ -3361,11 +3381,13 @@ or if SELinux is disabled, or if Emacs lacks SELinux support. */)
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if (!NILP (handler))
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return call2 (handler, Qfile_selinux_context, absname);
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file = SSDATA (ENCODE_FILE (absname));
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#if HAVE_LIBSELINUX
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if (is_selinux_enabled ())
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if (selinux_enabled_p (file))
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{
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char *con;
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int conlength = lgetfilecon (SSDATA (ENCODE_FILE (absname)), &con);
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int conlength = lgetfilecon (file, &con);
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if (conlength > 0)
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{
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context_t context = context_new (con);
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@ -3384,7 +3406,7 @@ or if SELinux is disabled, or if Emacs lacks SELinux support. */)
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|| errno == ENOTSUP))
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report_file_error ("getting SELinux context", absname);
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}
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#endif
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#endif /* HAVE_LIBSELINUX */
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return list4 (user, role, type, range);
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}
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@ -3410,10 +3432,11 @@ or if Emacs was not compiled with SELinux support. */)
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Lisp_Object type = CAR_SAFE (CDR_SAFE (CDR_SAFE (context)));
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Lisp_Object range = CAR_SAFE (CDR_SAFE (CDR_SAFE (CDR_SAFE (context))));
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char *con;
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const char *name;
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bool fail;
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int conlength;
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context_t parsed_con;
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#endif
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#endif /* HAVE_LIBSELINUX */
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absname = Fexpand_file_name (filename, BVAR (current_buffer, directory));
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@ -3424,11 +3447,13 @@ or if Emacs was not compiled with SELinux support. */)
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return call3 (handler, Qset_file_selinux_context, absname, context);
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#if HAVE_LIBSELINUX
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if (is_selinux_enabled ())
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encoded_absname = ENCODE_FILE (absname);
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name = SSDATA (encoded_absname);
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if (selinux_enabled_p (name))
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{
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/* Get current file context. */
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encoded_absname = ENCODE_FILE (absname);
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conlength = lgetfilecon (SSDATA (encoded_absname), &con);
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conlength = lgetfilecon (name, &con);
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if (conlength > 0)
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{
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parsed_con = context_new (con);
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@ -3469,7 +3494,7 @@ or if Emacs was not compiled with SELinux support. */)
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else
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report_file_error ("Doing lgetfilecon", absname);
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}
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#endif
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#endif /* HAVE_LIBSELINUX */
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return Qnil;
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}
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@ -3860,11 +3885,12 @@ static Lisp_Object
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read_non_regular (Lisp_Object state)
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{
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union read_non_regular *data = XFIXNUMPTR (state);
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int nbytes = emacs_fd_read (data->s.fd,
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((char *) BEG_ADDR + PT_BYTE - BEG_BYTE
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+ data->s.inserted),
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data->s.trytry);
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return make_fixnum (nbytes);
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intmax_t nbytes
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= emacs_fd_read (data->s.fd,
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((char *) BEG_ADDR + PT_BYTE - BEG_BYTE
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+ data->s.inserted),
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data->s.trytry);
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return make_int (nbytes);
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}
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@ -4002,13 +4028,19 @@ at the start and end of the buffer) and (2) it puts less data in the
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undo list. When REPLACE is non-nil, the second return value is the
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number of characters that replace previous buffer contents.
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If REPLACE is the symbol `if-regular', then eschew preserving marker
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positions or the undo list if REPLACE is nil if FILENAME is not a
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regular file. Otherwise, signal an error if REPLACE is non-nil and
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FILENAME is not a regular file.
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This function does code conversion according to the value of
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`coding-system-for-read' or `file-coding-system-alist', and sets the
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variable `last-coding-system-used' to the coding system actually used.
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In addition, this function decodes the inserted text from known formats
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by calling `format-decode', which see. */)
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(Lisp_Object filename, Lisp_Object visit, Lisp_Object beg, Lisp_Object end, Lisp_Object replace)
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(Lisp_Object filename, Lisp_Object visit, Lisp_Object beg, Lisp_Object end,
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Lisp_Object replace)
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{
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struct stat st;
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struct timespec mtime;
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@ -4123,24 +4155,27 @@ by calling `format-decode', which see. */)
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report_file_error ("Input file status", orig_filename);
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mtime = get_stat_mtime (&st);
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/* This code will need to be changed in order to work on named
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pipes, and it's probably just not worth it. So we should at
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least signal an error. */
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/* The REPLACE code will need to be changed in order to work on
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named pipes, and it's probably just not worth it. So we should
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at least signal an error. */
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if (!S_ISREG (st.st_mode))
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{
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regular = false;
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if (! NILP (visit))
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{
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eassert (inserted == 0);
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goto notfound;
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}
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if (!NILP (replace))
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xsignal2 (Qfile_error,
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build_string ("not a regular file"), orig_filename);
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{
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if (!EQ (replace, Qif_regular))
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xsignal2 (Qfile_error,
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build_string ("not a regular file"), orig_filename);
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else
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/* Set REPLACE to Qunbound, indicating that we are trying
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to replace the buffer contents with that of a
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non-regular file. */
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replace = Qunbound;
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}
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seekable = emacs_fd_lseek (fd, 0, SEEK_CUR) < 0;
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seekable = emacs_fd_lseek (fd, 0, SEEK_CUR) != (off_t) -1;
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if (!NILP (beg) && !seekable)
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xsignal2 (Qfile_error,
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build_string ("cannot use a start position in a non-seekable file/device"),
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@ -4316,7 +4351,8 @@ by calling `format-decode', which see. */)
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method and hope for the best.
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But if we discover the need for conversion, we give up on this method
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and let the following if-statement handle the replace job. */
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if (!NILP (replace)
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if ((!NILP (replace)
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&& !BASE_EQ (replace, Qunbound))
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&& BEGV < ZV
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&& (NILP (coding_system)
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|| ! CODING_REQUIRE_DECODING (&coding)))
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@ -4503,7 +4539,9 @@ by calling `format-decode', which see. */)
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is needed, in a simple way that needs a lot of memory.
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The preceding if-statement handles the case of no conversion
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in a more optimized way. */
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if (!NILP (replace) && ! replace_handled && BEGV < ZV)
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if ((!NILP (replace)
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&& !BASE_EQ (replace, Qunbound))
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&& ! replace_handled && BEGV < ZV)
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{
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ptrdiff_t same_at_start_charpos;
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ptrdiff_t inserted_chars;
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@ -4688,6 +4726,12 @@ by calling `format-decode', which see. */)
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prepare_to_modify_buffer (PT, PT, NULL);
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}
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/* If REPLACE is Qunbound, buffer contents are being replaced with
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text read from a FIFO. Erase the entire buffer. */
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if (BASE_EQ (replace, Qunbound))
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del_range (BEG, Z);
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move_gap_both (PT, PT_BYTE);
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/* Ensure the gap is at least one byte larger than needed for the
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@ -4696,7 +4740,8 @@ by calling `format-decode', which see. */)
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if (GAP_SIZE <= total)
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make_gap (total - GAP_SIZE + 1);
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if (beg_offset != 0 || !NILP (replace))
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if (beg_offset != 0 || (!NILP (replace)
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&& !EQ (replace, Qunbound)))
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{
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if (emacs_fd_lseek (fd, beg_offset, SEEK_SET) < 0)
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report_file_error ("Setting file position", orig_filename);
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@ -4729,6 +4774,7 @@ by calling `format-decode', which see. */)
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if (!seekable && NILP (end))
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{
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Lisp_Object nbytes;
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intmax_t number;
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/* Read from the file, capturing `quit'. When an
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error occurs, end the loop, and arrange for a quit
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@ -4744,18 +4790,20 @@ by calling `format-decode', which see. */)
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break;
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}
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this = XFIXNUM (nbytes);
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if (!integer_to_intmax (nbytes, &number)
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&& number > PTRDIFF_MAX)
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buffer_overflow ();
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this = number;
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}
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else
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{
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/* Allow quitting out of the actual I/O. We don't make text
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part of the buffer until all the reading is done, so a C-g
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here doesn't do any harm. */
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this = emacs_fd_read (fd,
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((char *) BEG_ADDR + PT_BYTE - BEG_BYTE
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+ inserted),
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trytry);
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}
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/* Allow quitting out of the actual I/O. We don't make text
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part of the buffer until all the reading is done, so a
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C-g here doesn't do any harm. */
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this = emacs_fd_read (fd,
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((char *) BEG_ADDR + PT_BYTE - BEG_BYTE
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+ inserted),
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trytry);
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if (this <= 0)
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{
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@ -4940,9 +4988,14 @@ by calling `format-decode', which see. */)
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Funlock_file (BVAR (current_buffer, file_truename));
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Funlock_file (filename);
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}
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#if !defined HAVE_ANDROID || defined ANDROID_STUBIFY
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/* Under Android, modtime and st.st_size can be valid even if FD
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is not a regular file. */
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if (!regular)
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xsignal2 (Qfile_error,
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build_string ("not a regular file"), orig_filename);
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#endif /* !defined HAVE_ANDROID || defined ANDROID_STUBIFY */
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}
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if (set_coding_system)
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@ -6810,9 +6863,11 @@ This includes interactive calls to `delete-file' and
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#ifndef DOS_NT
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defsubr (&Sfile_system_info);
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#endif
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#endif /* DOS_NT */
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#ifdef HAVE_SYNC
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defsubr (&Sunix_sync);
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#endif
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#endif /* HAVE_SYNC */
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DEFSYM (Qif_regular, "if-regular");
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}
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Loading…
Add table
Reference in a new issue