Root has carte blanche to both read unreadable files and write
unwritable files -- the file system does not prevent this. So,
alert root when opening a file that is intended to be read-only.
This fulfills https://savannah.gnu.org/bugs/?58685.
Requested-by: Marius Bakke <mbakke@fastmail.com>
Also, remove an unneeded 'if', as parse_escape_sequence() is only
ever called when there are at least two bytes after the Esc code.
(If there were not, the 'for' loop after calling convert_sequence()
would use an uninitialized 'consumed' value.)
Rereading is unlikely to fail, but *if* it fails, maybe there is a
serious problem and the user wants to try and fix it before saving
the buffer and thus overwriting the original file.
After thinking about it, I don't like it that nano makes an unrequested
failsafe backup: in the vast, vast majority of cases it is a waste both
of time and of disk wear. If the user is worried about data loss, they
can use --backup. The fsync() after writing out the buffer (added in
commit a84cdaaa) already reduces the chances on data loss somewhat.
This change moves the code responsible for backup creation to a new,
separate function, backup_file(). This function returns a boolean
indicating whether saving the buffer should proceed or not.
Signed-off-by: Michalis Kokologiannakis <michalis@mpi-sws.org>
The escape-sequence codes for the different keypad keys are simply
the relevant ASCII code plus 0x40, so they are easy to translate.
Also, do not accept keypad keys with multiple modifiers (Shift+Alt,
Shift+Ctrl, Alt+Ctrl, Shift+Alt+Ctrl) -- report "Unknown sequence"
for those.
Until now, on an xterm, Shift plus any keypad key would say
"Unknown sequence", which is not useful. On other terminal
emulators (urxvt, Pantheon, LXTerminal), Shift plus a keypad
key already produces the relevant digit or symbol, so this
change harmonizes the behavior of the different emulators.
However, on a Linux console, Shift plus a keypad key moves
the cursor and selects the text that is passed over. And
holding Alt while pressing a keypad key does nothing at all.
For the operator keys on the numeric keypad (/, *, -, and +),
make both the Alt and the Ctrl modifier a no-op.
This fixes https://savannah.gnu.org/bugs/?58731.
Bug existed since version 2.9.3, commit e734488c.
The file-saving procedure that nano followed was not crash-safe
under ext4 (and perhaps other filesystems) when editing existing
files. Specifically, modifying an existing file could lead to data
loss, since a modified file is not replaced atomically on disk.
Using "-B" did not ensure crash-safety either since the backup might
not have persisted on disk when the writeout of the file started.
In addition, if I/O pressure filled up the remaining disk space
after an existing file is truncated during save, nano would not
be able to finish saving the file, which would remain truncated.
This change addresses these issues by making nano do the following:
1) Make a temporary backup of the file being written so that there
is no time window such that (a) an existing file is truncated, and
(b) the buffer corresponding to said file has not been flushed to
disk. Such time windows are dangerous because, under certain
circumstances, they can lead to data loss on some filesystems.
The backup is made by copying the original file, and a second
attempt to HOME is made in case that first copy fails.
2) Use fsync() so that, when the save finishes, it is certain
that the file has been successfully written to disk.
This addresses https://savannah.gnu.org/bugs/?58642.
Signed-off-by: Michalis Kokologiannakis <michalis@mpi-sws.org>
This allows pasting six hexadecimal digits after typing M-V
in order to enter a specific Unicode character.
This fixes https://savannah.gnu.org/bugs/?58730.
Bug existed since version 4.8, since bracketed pastes
were introduced in commit f705a967.
The codes from (for example) U+D800 to U+DFFF are invalid. If any
such invalid code is entered at the Unicode Input prompt, nano should
not act as if the code was accepted and inserted into the buffer, and
should certainly not mark the buffer as Modified.
This fixes https://savannah.gnu.org/bugs/?58714.
Bug existed since version 4.9, commit b3faf353.
There is no need to place the cursor up front, as the drawing of
each name includes the coordinates where the name must be drawn.
Also, trim two comments and reshuffle a free().
Benno Schulenberg