Make it possible to build curl for Windows CE using the CeGCC toolchain.
With both CMake and autotools, including tests and examples, also in CI.
The build configuration is the default one with Schannel enabled. No
3rd-party dependencies have been tested.
Also revive old code to make Schannel build with Windows CE, including
certificate verification.
Builds have been throughougly tested. But, I've made no functional tests
for this PR. Some parts (esp. file operations, like truncate and seek)
are stubbed out and likely broken as a result. Test servers build, but
they do not work on Windows CE. This patch substitutes `fstat()` calls
with `stat()`, which operate on filenames, not file handles. This may or
may not work and/or may not be secure.
About CeGCC: I used the latest available macOS binary build v0.59.1
r1397 from 2009, in native `mingw32ce` build mode. CeGCC is in effect
MinGW + GCC 4.4.0 + old/classic-mingw Windows headers. It targets
Windows CE v3.0 according to its `_WIN32_WCE` value. It means this PR
restores portions of old/classic-mingw support. It makes the Windows CE
codepath compatible with GCC 4.4.0. It also adds workaround for CMake,
which cannot identify and configure this toolchain out of the box.
Notes:
- CMake doesn't recognize CeGCC/mingw32ce, necessitating tricks as seen
with Amiga and MS-DOS.
- CMake doesn't set `MINGW` for mingw32ce. Set it and `MINGW32CE`
manually as a helper variable, in addition to `WINCE` which CMake sets
based on `CMAKE_SYSTEM_NAME`.
- CMake fails to create an implib for `libcurl.dll`, due to not
recognizing the platform as a Windowsy one. This patch adds the
necessary workaround to make it work.
- headers shipping with CeGCC miss some things curl needs for Schannel
support. Fixed by restoring and renovating code previously deleted
old-mingw code.
- it's sometime non-trivial to figure out if a fallout is WinCE,
mingw32ce, old-mingw, or GCC version-specific.
- WinCE is always Unicode. With exceptions: no `wmain`,
`GetProcAddress()`.
- `_fileno()` is said to convert from `FILE *` to `void *` which is
a Win32 file `HANDLE`. (This patch doesn't use this, but with further
effort it probably could be.)
https://stackoverflow.com/questions/3989545/how-do-i-get-the-file-handle-from-the-fopen-file-structure
- WinCE has no signals, current directory, stdio/CRT file handles, no
`_get_osfhandle()`, no `errno`, no `errno.h`. Some of this stuff is
standard C89, yet missing from this platform. Microsoft expects
Windows CE apps to use Win32 file API and `FILE *` exclusively.
- revived CeGCC here (not tested for this PR):
https://building.enlyze.com/posts/a-new-windows-ce-x86-compiler-in-2024/
On `UNDER_CE` vs. `_WIN32_WCE`: (This patch settled on `UNDER_CE`)
- A custom VS2008 WinCE toolchain does not set any of these.
The compiler binaries don't contain these strings, and has no compiler
option for targeting WinCE, hinting that a vanilla toolchain isn't
setting any of them either.
- `UNDER_CE` is automatically defined by the CeGCC compiler.
https://cegcc.sourceforge.net/docs/details.html
- `UNDER_CE` is similar to `_WIN32`, except it's not set automatically
by all compilers. It's not supposed to have any value, like a version.
(Though e.g. OpenSSL sets it to a version)
- `_WIN32_WCE` is the CE counterpart of the non-CE `_WIN32_WINNT` macro.
That does return the targeted Windows CE version.
- `_WIN32_WCE` is not defined by compilers, and relies on a header
setting it to a default, or the build to set it to the desired target
version. This is also how `_WIN32_WINNT` works.
- `_WIN32_WCE` default is set by `windef.h` in CeGCC.
- `_WIN32_WCE` isn't set to a default by MSVC Windows CE headers (the
ones I checked at least).
- CMake sets `_WIN32_WCE=<ver>`, `UNDER_CE`, `WINCE` for MSVC WinCE.
- `_WIN32_WCE` seems more popular in other projects, including CeGCC
itself. `zlib` is a notable exception amongst curl dependencies,
which uses `UNDER_CE`.
- Since `_WIN32_WCE` needs "certain" headers to have it defined, it's
undefined depending on headers included beforehand.
- `curl/curl.h` re-uses `_WIN32_WCE`'s as a self-guard, relying on
its not-(necessarily)-defined-by-default property:
25b445e479/include/curl/curl.h (L77)
Toolchain downloads:
- Windows:
https://downloads.sourceforge.net/cegcc/cegcc/0.59.1/cegcc_mingw32ce_cygwin1.7_r1399.tar.bz2
- macOS Intel:
https://downloads.sourceforge.net/cegcc/cegcc/0.59.1/cegcc_mingw32ce_snowleopard_r1397.tar.bz2Closes#15975
The SSL_Session object is mutated during connection inside openssl,
and it might not be thread-safe. Besides, according to documentation
of openssl:
```
SSL_SESSION objects keep internal link information about the session
cache list, when being inserted into one SSL_CTX object's session
cache. One SSL_SESSION object, regardless of its reference count,
must therefore only be used with one SSL_CTX object (and the SSL
objects created from this SSL_CTX object).
```
If I understand correctly, it is not safe to share it even in a
single thread.
Instead, serialize the SSL_SESSION before adding it to the cache,
and deserialize it after retrieving it from the cache, so that no
concurrent write to the same object is infeasible.
Also
- add a ci test for thread sanitizer
- add a test for sharing ssl sessions concurrently
- avoid redefining memory functions when not building libcurl, but
including the soruce in libtest
- increase the concurrent connections limit in sws
Notice that there are fix for a global data race for openssl which
is not yet release. The fix is cherry pick for the ci test with
thread sanitizer.
d8def79838Closes#14751
