If the call to `qf_setup_state()` in `qf_init_ext()` fails, control flow jumps
to label `qf_init_end` where a call to `qf_update_buffer()` is made with
`old_last` as a function call argument.
Prior to this patch, `old_last` would not yet have been initialized to its
default value of `NULL`, resulting in `qf_update_buffer()` attempting to compare
against its uninitialized value (quickfix.c:3882) then later forwarding it to
`qf_fill_buffer()` where the address is dereferenced and repeatedly read from/
written to for performing core qflist operations.
Depending on what the default value of `old_last` was, the results may range
from a best case scenario of neovim terminating with SIGSEGV from an attempt to
dereference an invalid pointer (quickfix.c:4056) to memory corruption if it
contained some other value that results in `qfp` being initialized from
`old_last->qf_next` (after which it is subsequently written to and read from in
a fairly arbitrary fashion).
Though extremely unlikely, it's possible for there to be security considerations
as a user can ensure that the next call to `qf_setup_state()` fails.
This patch ensures that `old_last` is NULL-assigned before control flow jumps to
`qf_init_end`.
Closes#20639.
* fix(man): handle absolute paths as :Man targets
Previously, attempting to provide `:Man` with an absolute path as the name would
cause neovim to return the following error:
```
Error detected while processing command line:
/usr/local/share/nvim/runtime/lua/man.lua:690: /usr/local/share/nvim/runtime/lua/man.lua:683: Vim:E426: tag not found: nil(nil)
Press ENTER or type command to continue
```
..because it would try to validate the existence of a man page for the provided
name by executing `man -w /some/path` which (on at least some Linux machines
[0]) returns `/some/path` instead of the path to the nroff files that would be
formatted to satisfy the man(1) lookup.
While man pages are not normally named after absolute paths, users shouldn't be
blamed for trying. Given such a name/path, neovim would **not** complain that
the path didn't have a corresponding man file but would error out when trying
to call the tag function for the null-propagated name-and-section `nil(nil)`.
(The same underlying error existed before this function was ported to lua, but
did not exhibit the lua-specific `nil(nil)` name; instead a tag lookup for `()`
would fail and error out.)
With this patch, we detect the case where `man -w ...` returns the same value as
the provided name to not only prevent invoking the tag function for a
non-existent/malformed name+sect but also to properly report the non-existence
of a man page for the provided lookup (the absolute path).
While man(1) can be used to directly read an nroff-formatted document via `man
/path/to/nroff.doc`, `:Man /path/to/nroff.doc` never supported this behavior so
no functionality is lost in case the provided path _was_ an nroff file.
[0]: `man -w /absolute/path` returning `/absolute/path` observed on an Ubuntu
18.04 installation.
* test: add regression test for #20624
Add a functional test to `man_spec.lua` to check for a regression for #20624 by
first obtaining an absolute path to a random file and materializing it to disk,
then attempting to query `:Man` for an entry by that same name/path.
The test passes if nvim correctly reports that there is no man page
correspending to the provided name/path and fails if any other error (or no
error) is shown.
Per CMAKE docs, CMAKE_HOST_SYSTEM_VERSION is the result of `uname -r`:
https://cmake.org/cmake/help/v3.4/variable/CMAKE_HOST_SYSTEM_VERSION.html?highlight=uname
A numeric version string for the system. On systems that support
uname, this variable is set to the output of uname -r. On other
systems this is set to major-minor version numbers.
On Windows it is something like "6.1", so it won't match ".*-Microsoft".
Closes#7329
BSD Make will give preference to a BSDmakefile in the same directory
over a generic Makefile; this can be used to instruct BSD users to build
neovim with GNU Make (gmake) instead.
Otherwise, a flood of syntax errors stemming from the GNU-specific
Makefile will be displayed - which most BSD users are accustomed to, but
may confuse beginners nevertheless.
Mahmoud Al-Qudsi