Missed this when changing the code back to be like the old version.
com is now a parameter.
The only plausible way to trigger this would be to pass a loader
pathname close to MAX_PATH characters long, and then remove that
path prior to the first sys_faccessat.
This implements proposals 1 and 2a from this gist:
https://gist.github.com/mrdomino/2222cab61715fd527e82e036ba4156b1
The only reason to use realpath from the loader was to try to prevent a
TOCTOU between the loader and the binary. But this is only a real issue
in set-id contexts, and in those cases there is already a canonical way
to do it: `/dev/fd`, passed by the kernel to the loader, so all we have
to do is pass that along to the binary.
Aside from realpath, there is no reason to absolutize the path we supply
to the binary, since it can call `getcwd` as well as we can, and on non-
M1 the binary is in a much better position to make that call.
Since we no longer absolutize the path, the binary does need to do this,
so we make its argv-parsing code generic and apply that to the different
possible places the path could come from. This means that `_` is finally
usable as a relative path, as a nice side benefit.
The M1 realpath code had a significant bug - it uses the wrong offset to
truncate the `.ape` in the `$prog.ape` case.
This PR also fixes a regression in `ape $progname` out of `$PATH` on the
two BSDs (Free and Net) that did not implement `RealPath`.
Fixes a regression in GetProgramExecutableName on Linux against old
loaders. In the loader case, /proc/self/exe gives the loader's path.
We tried to detect this by checking for `/usr/bin/ape`. But that is
only one of the possible places the loader could be.
Somehow or another, I previously had missed `BUILD.mk` files.
In the process I found a few straggler cases where the modeline was
different from the file, including one very involved manual fix where a
file had been treated like it was ts=2 and ts=8 on separate occasions.
The commit history in the PR shows the gory details; the BUILD.mk was
automated, everything else was mostly manual.
The ape loader now passes the program executable name directly as a
register. `x2` is used on aarch64, `%rdx` on x86_64. This is passed
as the third argument to `cosmo()` (M1) or `Launch` (non-M1) and is
assigned to the global `__program_executable_name`.
`GetProgramExecutableName` now returns this global's value, setting
it if it is initially null. `InitProgramExecutableName` first tries
exotic, secure methods: `KERN_PROC_PATHNAME` on FreeBSD/NetBSD, and
`/proc` on Linux. If those produce a reasonable response (i.e., not
`"/usr/bin/ape"`, which happens with the loader before this change),
that is used. Otherwise, if `issetugid()`, the empty string is used.
Otherwise, the old argv/envp parsing code is run.
The value returned from the loader is always the full absolute path
of the binary to be executed, having passed through `realpath`. For
the non-M1 loader, this necessitated writing `RealPath`, which uses
`readlinkat` of `"/proc/self/fd/[progfd]"` on Linux, `F_GETPATH` on
Xnu, and the `__realpath` syscall on OpenBSD. On FreeBSD/NetBSD, it
punts to `GetProgramExecutableName`, which is secure on those OSes.
With the loader, all platforms now have a secure program executable
name. With no loader or an old loader, everything still works as it
did, but setuid/setgid is not supported if the insecure pathfinding
code would have been needed.
Fixes#991.
At least in neovim, `│vi:` is not recognized as a modeline because it
has no preceding whitespace. After fixing this, opening a file yields
an error because `net` is not an option. (`noet`, however, is.)
* Introduce env.com
Handy tool for debugging environment issues.
* Inject path as COSMOPOLITAN_PROGRAM_EXECUTABLE
`argv[0]` was previously being used as a communication channel between
the loader and the binary, giving the binary its full path for use e.g.
in `GetProgramExecutableName`. But `argv[0]` is not a good channel for
this; much of what made 2a3813c6 so gross is due to that.
This change fixes the issue by preserving `argv[0]` and establishing a
new communication channel: `COSMOPOLITAN_PROGRAM_EXECUTABLE`.
The M1 loader will always set this as the first variable. Linux should
soon follow. On the other side, `GetProgramExecutableName` checks that
variable first. If it sees it, it trusts it as-is.
A lot of the churn in `ape/ape-m1.c` in this change is actually backing
out hacks introduced in 2a3813c6; the best comparison is:
git diff 2a3813c6^..
* Implement __zipos_dup
Makes ZiposHandle reference-counted by an `rc` field in a union with its
freelist `next` pointer. The functions `__zipos_free` and `__zipos_keep`
function as incref/decref for it. Adds `__zipos_postdup` to fix metadata
on file descriptors after dup-like operations, and adds zipos support to
`sys_dup_nt` + `sys_close_nt`.
* Remove noop __zipos_postdup
rc is never a zipos file because it is always a previously unused file
descriptor. fd is never a zipos file because that case has been handled
above by __zipos_fcntl.
On UNIX if dup2(newfd) was a ZipOS file descriptor, then its resources
weren't being released, and the newly created file descriptor would be
mistaken for ZipOS due to its memory not being cleared. On Windows, an
issue also existed relating to newfd resources not being released.
Munging of paths passed inside the system() interpreter command is no
longer supported. You have to pass your paths to posix_spawn() or the
execve() family of functions if you want them to be munged. The first
three characters must match `^/[a-z]/` in which case, it'll be turned
into a DOS-style drive path with backslashes.
- Introduce MAP_JIT which is zero on other platforms
- Invent __jit_begin() and __jit_end() which wrap Apple's APIs
- Runtime dispatch to sys_icache_invalidate() in __clear_cache()
- Use good ELF technique in cosmo_dlopen()
- Make strerror() conform more to other libc impls
- Introduce __clear_cache() and use it in cosmo_dlopen()
- Remove libc/fmt/fmt.h header (trying to kill off LIBC_FMT)
After hearing horror stories from a trusted colleague, I don't think
this is the kind of API we want to be supporting. Also SQLite wisdom
regarding fdatasync() has been added to the documentation.
We now have an `#include <cxxabi.h>` header which defines all the APIs
Cosmopolitan's implemented so far. The `cosmocc` README.md file is now
greatly expanded with documentation.
Our makefile generator now accepts badly formatted include lines. It's
now more hermetic with better error checking in the cosmo repo, and it
can be configured to not be hermetic at all.
Using `cosmocc -std=c11` was causing `ucontext_t` to become misaligned.
This change also adds the GNU constants on x86_64 for accessing general
registers, so you will not need `#ifdef`s to support both Cosmo and GNU
wait4() is now solid enough to run `make -j100` on Windows. You can now
use MSG_DONTWAIT on Windows. There was a handle leak in accept() that's
been fixed. Our WIN32 overlapped i/o code has been simplified. Priority
class now inherits into subprocesses, so the verynice command will work
and the signal mask will now be inherited by execve() and posix_spawn()
