Very old shells suffered from bugs which meant that prefixing variables
with an "x" to ensure that the lefthand side of a comparison always
started with an alphanumeric character was needed. Modern shells don't
suffer from this issue (i.e Bash was fixed in 1996).
In any case, we've already got unprefixed checks used in our codebase,
i.e https://github.com/bitcoin/bitcoin/blob/master/configure.ac#L292,
and have dependencies (in depends) that also use unprefixed comparisons.
I think it's time that we can consolidate on not using the x-prefix
workaround. At best it's mostly just confusing.
More info:
https://github.com/koalaman/shellcheck/wiki/SC2268https://www.vidarholen.net/contents/blog/?p=1035
68e5aafde3 build: add `--enable-lto` configuration option (fanquake)
Pull request description:
It's been 5 years since using LTO was first suggested for use when building Bitcoin Core, and it's time to revisit it again. Compilers, and their LTO implementations, have matured, and Bitcoin Core has come a long way in terms of pruning dependencies which may have proved troublesome (i.e Boost previously had issues when using LTO). We'll have even less Boost code after moving to `std::filesystem` (#20744).
Experimenting with LTO came up on IRC last night:
> sipa: jamesob: i'm interested in knowing whether "-flto" and/or "-fdata-sections -ffunction-sections -Wl,--gc-sections" are possible/beneficial with our current compiler suite; what would be a good way to have your test infrastructure benchmark things?
So this PR just adds the bare minimum to make it easier to configure, compile and perform some bench-marking using `-flto`. This PR doesn't do anything depends wise, however if we decide this is what we want to do, I'll expand the changes here.
I had previously had a PR open (#18605) to perform link time garbage collection (`-ffunction-sections -fdata-sections` & `-Wl,--gc-sections`), however moving straight to using LTO would be preferable.
Note that our minimum required set of compilers, GCC 8.1 and Clang 7, all support the `-flto` option.
Related #18579.
Previous discussion: #10616, #14277.
Previous related PRs: #10800 (`-flto`), #16791 (ThinLTO).
Guix build:
```bash
bash-5.1# find guix-build-$(git rev-parse --short=12 HEAD)/output/ -type f -print0 | env LC_ALL=C sort -z | xargs -r0 sha256sum
1f3a7c5be4169aaa444b481d3e65a7bb72da9007fee6e6c416ded2e70f97374b guix-build-68e5aafde3e8/output/aarch64-linux-gnu/SHA256SUMS.part
fa8f4cf223d9aaf0b2c1ef55ce61256a19cd1ad7f42b99d0b98c9a52fe6ad8ba guix-build-68e5aafde3e8/output/aarch64-linux-gnu/bitcoin-68e5aafde3e8-aarch64-linux-gnu-debug.tar.gz
9a9967078cd1849b4e85db619e1f55d305c6d44e9e013067c0e8d62c1ba54087 guix-build-68e5aafde3e8/output/aarch64-linux-gnu/bitcoin-68e5aafde3e8-aarch64-linux-gnu.tar.gz
18c71f30722102baaf3dfda67f7c7aac38723510b142e8df8ee7063c5d499368 guix-build-68e5aafde3e8/output/arm-linux-gnueabihf/SHA256SUMS.part
0854cc0d17c045a118df2a24e4cf36d727e7e7e2dea37c2492ee21b71cb79b4b guix-build-68e5aafde3e8/output/arm-linux-gnueabihf/bitcoin-68e5aafde3e8-arm-linux-gnueabihf-debug.tar.gz
215256897dde4e8412ed60473376c694a80c5479fb08039107fb62435f2816ef guix-build-68e5aafde3e8/output/arm-linux-gnueabihf/bitcoin-68e5aafde3e8-arm-linux-gnueabihf.tar.gz
5fad0d9d12bc514ec46ed5d66fd29b7da1376a4a69c3b692936f1ab2356e2f85 guix-build-68e5aafde3e8/output/dist-archive/bitcoin-68e5aafde3e8.tar.gz
4f32989d4ab1946048ca7caee9a983fa875be262282562f5a3e040f4bf92158e guix-build-68e5aafde3e8/output/powerpc64-linux-gnu/SHA256SUMS.part
ae45df309ae8ada52891efac0a369a69fed4ab93847a7bc4150a62230df4c8d7 guix-build-68e5aafde3e8/output/powerpc64-linux-gnu/bitcoin-68e5aafde3e8-powerpc64-linux-gnu-debug.tar.gz
0ced227de15cb578567131271e2effe80681b4d7a436c92bf1caec735a576fa4 guix-build-68e5aafde3e8/output/powerpc64-linux-gnu/bitcoin-68e5aafde3e8-powerpc64-linux-gnu.tar.gz
26fc5d2ccc1bc17ee0a146cacada6f4909d90c136ae640c8337332adce414ee0 guix-build-68e5aafde3e8/output/powerpc64le-linux-gnu/SHA256SUMS.part
9956b544d90a62a8ba9fc9dc6b6b7f0efe193357332ec19e88053a89d4aab37e guix-build-68e5aafde3e8/output/powerpc64le-linux-gnu/bitcoin-68e5aafde3e8-powerpc64le-linux-gnu-debug.tar.gz
be8e39ceea1d36086ce5fa93bfb138c68d3bdf0dd6950b192dfa27a65cce3836 guix-build-68e5aafde3e8/output/powerpc64le-linux-gnu/bitcoin-68e5aafde3e8-powerpc64le-linux-gnu.tar.gz
a7755edc394972885c4c77a7798007e5ba4126b177c4ff6224275c4fb8f3b1c4 guix-build-68e5aafde3e8/output/riscv64-linux-gnu/SHA256SUMS.part
b6d252993d8aae7582ad6385fe53c61c54c284c68ece6cb2b2d1ac9554e06139 guix-build-68e5aafde3e8/output/riscv64-linux-gnu/bitcoin-68e5aafde3e8-riscv64-linux-gnu-debug.tar.gz
bb4860f3bbd815f800333124ff901d880741792ab47097f49bda3a6931144da0 guix-build-68e5aafde3e8/output/riscv64-linux-gnu/bitcoin-68e5aafde3e8-riscv64-linux-gnu.tar.gz
3dd17deed5c5935fb28b62dfc7afca5caab0d67862cdcbf3337edae73e1d0c4c guix-build-68e5aafde3e8/output/x86_64-apple-darwin19/SHA256SUMS.part
fa2d68c54fda0816188c81ce2201a77340b82645da2ffe412526f92c297a82df guix-build-68e5aafde3e8/output/x86_64-apple-darwin19/bitcoin-68e5aafde3e8-osx-unsigned.dmg
f6e5accdcd201f522b6426e4d8cc9b3643d4d43a57d268fa0e79ea9a34cfac01 guix-build-68e5aafde3e8/output/x86_64-apple-darwin19/bitcoin-68e5aafde3e8-osx-unsigned.tar.gz
4e5a127df957d1c73b65925d685f6620e7bc5667efcb6dcd98be76effc22fc12 guix-build-68e5aafde3e8/output/x86_64-apple-darwin19/bitcoin-68e5aafde3e8-osx64.tar.gz
56ccd216a69acafacbdc6bae0bdcc1faa50b6a51be1aebfa7068206c88b3241a guix-build-68e5aafde3e8/output/x86_64-linux-gnu/SHA256SUMS.part
77b93dd5fad322636853e5b0244ffafd97cc97f3b4b4ee755d5f830b75d77d13 guix-build-68e5aafde3e8/output/x86_64-linux-gnu/bitcoin-68e5aafde3e8-x86_64-linux-gnu-debug.tar.gz
1feda932fc127b900316a232432b91e46e57ee12a81e12a7d888fdc3296219c1 guix-build-68e5aafde3e8/output/x86_64-linux-gnu/bitcoin-68e5aafde3e8-x86_64-linux-gnu.tar.gz
aa7c53ab4164b3736049065c3c24391fc5bd7f26b4bda4aa877c378f0636a125 guix-build-68e5aafde3e8/output/x86_64-w64-mingw32/SHA256SUMS.part
5e76148e67aef7e91e70074bfadc08e94373449ac3b966f4343b04d230c778fd guix-build-68e5aafde3e8/output/x86_64-w64-mingw32/bitcoin-68e5aafde3e8-win-unsigned.tar.gz
34123e3d818beeb70113caeda66945bc7cb9d9e987515d5b149bd17b4b38da90 guix-build-68e5aafde3e8/output/x86_64-w64-mingw32/bitcoin-68e5aafde3e8-win64-debug.zip
2bba7f40a2b23c6ea3d47c4f564ab54201bf27f7f57103a98cc9bceea4e70c4d guix-build-68e5aafde3e8/output/x86_64-w64-mingw32/bitcoin-68e5aafde3e8-win64-setup-unsigned.exe
0e7e124144af4a92a4344cf70a3b7c06fbd2b8782aee7ede7263893afa3a5ef0 guix-build-68e5aafde3e8/output/x86_64-w64-mingw32/bitcoin-68e5aafde3e8-win64.zip
```
ACKs for top commit:
laanwj:
Code review ACK 68e5aafde3
Tree-SHA512: 5c25249cc178b9d54159e268390c974b739df9458d773e23c14b14d808f87f7afe314058b3c068601a9132042321973b0c9b6f81becb925665eca2738ae9a613
cf7292597e configure.ac: remove Bashism (Matt Whitlock)
Pull request description:
Configure scripts are supposed to adhere to the POSIX shell language. The POSIX `test` builtin does not implement an `==` operator. Bash does, but not all systems have Bash installed as `/bin/sh`. In particular, many systems use the lighter-weight Dash as the default POSIX shell. Dash emits the following error when running `configure`:
```
./configure: 39065: test: xno: unexpected operator
```
This PR removes the Bashism and restores correct operation with POSIX-compliant shells like Dash.
ACKs for top commit:
katesalazar:
ACK cf7292597e.
laanwj:
Code review ACK cf7292597e
Tree-SHA512: 578c873fba52e0472baed9e024bddcf58a0e088600bd5854f3011f1f8d135773ad923bb16baefc960d17ecedee9cc980b36aaa70fb32eb9bc7de93f7fe60541d
From what I can see the only platform this drops support for is CentOS
7. CentOS 7 reached the end of it's "full update" support at the end of
2020. It does receive maintenance updates until 2024, however I don't
think supporting glibc 2.17 until 2024 is realistic. Note that anyone
wanting to self-compile and target a glibc 2.17 runtime could build with
--disable-threadlocal.
glibc 2.18 was released in August 2013.
https://sourceware.org/legacy-ml/libc-alpha/2013-08/msg00160.html
29173d6c6c ubsan: add minisketch exceptions (Cory Fields)
54b5e1aeab Add thin Minisketch wrapper to pick best implementation (Pieter Wuille)
ee9dc71c1b Add basic minisketch tests (Pieter Wuille)
0659f12b13 Add minisketch dependency (Gleb Naumenko)
0eb7928ab8 Add MSVC build configuration for libminisketch (Pieter Wuille)
8bc166d5b1 build: add minisketch build file and include it (Cory Fields)
b2904ceb85 build: add configure checks for minisketch (Cory Fields)
b6487dc4ef Squashed 'src/minisketch/' content from commit 89629eb2c7 (fanquake)
Pull request description:
This takes over #21859, which has [recently switched](https://github.com/bitcoin/bitcoin/pull/21859#issuecomment-921899200) to my integration branch. A few more build issues came up (and have been fixed) since, and after discussing with sipa it was decided I would open a PR to shepherd any final changes through.
> This adds a `src/minisketch` subtree, taken from the master branch of https://github.com/sipa/minisketch, to prepare for Erlay implementation (see #21515). It gets configured for just supporting 32-bit fields (the only ones we're interested in in the context of Erlay), and some code on top is added:
> * A very basic unit test (just to make sure compilation & running works; actual correctness checking is done through minisketch's own tests).
> * A wrapper in `minisketchwrapper.{cpp,h}` that runs a benchmark to determine which field implementation to use.
Only changes since my last update to the branch in the previous PR have been rebasing on master and fixing an issue with a header in an introduced file.
ACKs for top commit:
naumenkogs:
ACK 29173d6c6c
Tree-SHA512: 1217d3228db1dd0de12c2919314e1c3626c18a416cf6291fec99d37e34fb6eec8e28d9e9fb935f8590273b8836cbadac313a15f05b4fd9f9d3024c8ce2c80d02
AC_DEFINE'd values won't be passed down to minisketch because it does not
use bitcoin-config.h. Thus we need a way to know if we should manually add
defines for minisketch files.
17ae2601c7 build: remove build stubs for external leveldb (Cory Fields)
Pull request description:
Presumably these stubs indicate to packagers that external leveldb is meant to be supported in some way. It is not. Remove the stubs to avoid sending any mixed messages.
For context, this was reported on IRC:
> \<Talkless> bitcoind fails to start with undefined symbol: _ZTIN7leveldb6LoggerE in Debian Sid after leveldb upgraded from 1.22 to 1.23: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=996486
ACKs for top commit:
fanquake:
ACK 17ae2601c7
hebasto:
ACK 17ae2601c7. I have reviewed the code and it looks OK, I agree it can be merged.
Tree-SHA512: 2f1ac2cb30dac64791933a245a2b66ce237bde3955e6f4a6b7ec181248f77a9b1b10597d865d3e2c2b6def696af70de40e905ec274e4ae7cccd1daf461473957
These tests are failing when run against OpenSSL 3, and have been
removed upstream, https://github.com/bitcoin-core/secp256k1/pull/983, so
disabled them for now to avoid `make check` failures.
Note that this will also remove warning output from our build, due to
the use of deprecated OpenSSL API functions. See #23048.
0f95247246 Integrate univalue into our buildsystem (Cory Fields)
9b49ed656f Squashed 'src/univalue/' changes from 98fadc0909..a44caf65fe (fanquake)
Pull request description:
This PR more tightly integrates building Univalue into our build system. This follows the same approach we use for [LevelDB](https://github.com/bitcoin-core/leveldb/), ([`Makefile.leveldb.include`](https://github.com/bitcoin/bitcoin/blob/master/src/Makefile.leveldb.include)), and [CRC32C](https://github.com/bitcoin-core/crc32c) ([`Makefile.crc32c.include`](https://github.com/bitcoin/bitcoin/blob/master/src/Makefile.crc32c.include)), and will be the same approach we use for [minisketch](https://github.com/sipa/minisketch); see #23114.
This approach yields a number of benefits, including:
* Faster configuration due to one less subconfigure being run during `./configure` i.e 22s with this PR vs 26s
* Faster autoconf i.e 13s with this PR vs 17s
* Improved caching
* No more issues with compiler flags i.e https://github.com/bitcoin/bitcoin/pull/12467
* More direct control means we can build exactly the objects we want
There might be one argument against making this change, which is that builders should have the option to use "proper shared/system libraries". However, I think that falls down for a few reasons. The first being that we already don't support building with a number of system libraries (secp256k1, leveldb, crc32c); some for good reason. Univalue is really the odd one out at the moment.
Note that the only fork of Core I'm aware of, that actively patches in support for using system libs, also explicitly marks them as ["DANGEROUS"](a886811721/configure.ac (L1430)) and ["NOT SUPPORTED"](a886811721/configure.ac (L1312)). So it would seem they exist more to satisfy a distro requirement, as opposed to something that anyone should, or would actually use in practice.
PRs like #22412 highlight the "issue" with us operating with our own Univalue fork, where we actively fix bugs, and make improvements, when upstream (https://github.com/jgarzik/univalue) may not be taking those improvements, and by all accounts, is not currently actively maintained. Bitcoin Core should not be hamstrung into not being able to fix bugs in a library, and/or have to litter our source with "workarounds", i.e #22412, for bugs we've already fixed, based on the fact that an upstream project is not actively being maintained. Allowing builders to use system libs is really only exacerbating this problem, with little benefit to our project. Bitcoin Core is not quite like your average piece of distro packaged software.
There is the potential for us to give the same treatment to libsecp256k1, however it seems doing that is currently less straightforward.
ACKs for top commit:
dongcarl:
ACK 0f95247246 less my comment above, always nice to have an include-able `sources.mk` which makes integration easier.
theuni:
ACK 0f95247246. Thanks fanquake for keeping this going.
Tree-SHA512: a7f2e41ee7cba06ae72388638e86b264eca1b9a8b81c15d1d7b45df960c88c3b91578b4ade020f8cc61d75cf8d16914575f9a78fa4cef9c12be63504ed804b99
Presumably these stubs indicate to packagers that external leveldb is meant to
be supported in some way. It is not. Remove the stubs to avoid sending any
mixed messages.
aa69fd6caf build: Drop -Wno-unused-local-typedef (Hennadii Stepanov)
672e8c5d07 build: remove -Wunused-variable (fanquake)
5239af0574 build: remove -Wswitch (fanquake)
0375906e0a build: use loop-analysis over range-loop-analysis (fanquake)
12712fa2c4 build: remove -Wsign-compare (fanquake)
Pull request description:
This remove the addition of flags that are already part of other options, such as `-Wall` or `-Wextra`; see each commit message for details. All of the flags being removed here already exist as part of `-Wall` as of GCC 8, or, for Clang, all exist in `-Wmost` (included in `-Wall)`, or as part of `-Wextra` as of Clang 7. Both of which are our minimum required compilers.
Also cherry-picks one change from #21458.
To give an example of how GCCs `-Wall` has changed over the last few releases:
### 11.x to trunk (12.x)
Added:
```bash
-Wzero-length-bounds
-Wmismatched-dealloc
-Wmismatched-new-delete (only for C/C++)
```
### 10.x to 11.x
Added:
```bash
-Warray-parameter=2 (C and Objective-C only)
-Wrange-loop-construct (only for C++)
-Wsizeof-array-div
-Wvla-parameter (C and Objective-C only)
```
Removed:
```bash
-Wenum-conversion in C/ObjC;
```
### 9.x to 10.x
Added:
```bash
-Wenum-conversion in C/ObjC;
-Wformat-overflow
-Wformat-truncation
-Wzero-length-bounds
```
### 8.x to 9.x
Added:
```bash
-Wpessimizing-move
```
Removed:
```bash
-Wstringop-truncation
```
### 7.x to 8.x
Added:
```bash
-Wcatch-value (C++ and Objective-C++ only)
-Wmissing-attributes
-Wmultistatement-macros
-Wrestrict
-Wsizeof-pointer-div
-Wstringop-truncation
```
[Clang Warning Options](https://clang.llvm.org/docs/DiagnosticsReference.html)
[GCC Warning Options](https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html)
ACKs for top commit:
meshcollider:
utACK aa69fd6caf
Tree-SHA512: 34dde6bd773c864202c151eaa35f902d03fb531c27fe5e1ef659225da03acade2efe5df56df3efb4df5bbded3d395348ce03c25b837fce83be53af3352f0f2bc
ce69e18947 scripts: remove pixie.py (fanquake)
00b85d0b13 scripts: only parse the binary once in security-check.py (fanquake)
cad40a5b16 scripts: use LIEF for ELF checks in security-check.py (fanquake)
8242ae230e scripts: only parse the binary once in symbol-check.py (fanquake)
309eac9019 scripts: use LIEF for ELF checks in symbol-check.py (fanquake)
610a8a8e39 test-*-check: Pass in *FLAGS and compile with them (Carl Dong)
Pull request description:
This finishes the transition to using LIEF for the ELF symbol and security checks.
Note that there's currently a work around used for identifying RISCV binaries (just checking the interpreter). I've sent a PR upstream, https://github.com/lief-project/LIEF/pull/562, and we should be able to drop that when using LIEF 0.12.0 and onwards.
ACKs for top commit:
dongcarl:
Code Review ACK ce69e18947
laanwj:
Code review ACK ce69e18947
Tree-SHA512: 911ba693cd9777ad1fc1f66dff6c4d3630a907351215380cbde5b14a4bbf5cf7eebf52eafa7e86b27deabd2d93d1b403f34aabd356b5ceaab3cc6e9941a01dd4
38fd709fa5 build: make --enable-werror just -Werror (fanquake)
Pull request description:
No longer special case a set of warnings, to make up our own -Werror,
just use -Werror outright. This shouldn't really have any effect on
existing builders, who were already using `--enable-werror`, and is more
inline with what they would expect `--enable-werror` to be, which is
erroring on any/all warnings.
We keep `-Wno-error=return-type` because we know that is broken when using
mingw-w64. It should only be applied when cross-compiling for Windows.
Similar to the change in #20544, but with (hopefully) less work-arounds,
and other bundled changes. A step towards some configure "cleanups".
ACKs for top commit:
hebasto:
ACK 38fd709fa5 (also see https://github.com/bitcoin/bitcoin/pull/23149#issuecomment-940420776), tested:
MarcoFalke:
Concept ACK 38fd709fa5
Tree-SHA512: 37f1857d9408442cab63e40f9280427b73e09cdf03146b19c1339d7e44abd78e93df7f270ca1da0e83b79343cd3ea915f7b9e4e347488b5bc5ceaaa7540e5926
This addresses issues like the one in #12467, where some of our compiler flags
end up being dropped during the subconfigure of Univalue. Specifically, we're
still using the compiler-default c++ version rather than forcing c++17.
We can drop the need subconfigure completely in favor of a tighter build
integration, where the sources are listed separately from the build recipes,
so that they may be included directly by upstream projects. This is
similar to the way leveldb build integration works in Core.
Core benefits of this approach include:
- Better caching (for ex. ccache and autoconf)
- No need for a slow subconfigure
- Faster autoconf
- No more missing compile flags
- Compile only the objects needed
There are no benefits to Univalue itself that I can think of. These changes
should be a no-op there, and to downstreams as well until they take advantage
of the new sources.mk.
This also removes the option to use an external univalue to avoid similar ABI
issues with mystery binaries.
Co-authored-by: fanquake <fanquake@gmail.com>
0bc666b053 doc: add info for debugging with relative paths (S3RK)
a8b515c317 configure: keep relative paths in debug info (S3RK)
Pull request description:
This is a follow-up for #20353 that fixes#21885
It also adds a small section to assist debugging without absolute paths in debug info.
ACKs for top commit:
kallewoof:
Tested ACK 0bc666b053
Zero-1729:
Light crACK 0bc666b053
Tree-SHA512: d4b75183c3d3a0f59fe786841fb230581de87f6fe04cf7224e4b89c520d45513ba729d4ad8c0e62dd1dbaaa7a25741f04d036bc047f92842e76c9cc31ea47fb2
4747da3a5b Add syscall sandboxing (seccomp-bpf) (practicalswift)
Pull request description:
Add experimental syscall sandboxing using seccomp-bpf (Linux secure computing mode).
Enable filtering of system calls using seccomp-bpf: allow only explicitly allowlisted (expected) syscalls to be called.
The syscall sandboxing implemented in this PR is an experimental feature currently available only under Linux x86-64.
To enable the experimental syscall sandbox the `-sandbox=<mode>` option must be passed to `bitcoind`:
```
-sandbox=<mode>
Use the experimental syscall sandbox in the specified mode
(-sandbox=log-and-abort or -sandbox=abort). Allow only expected
syscalls to be used by bitcoind. Note that this is an
experimental new feature that may cause bitcoind to exit or crash
unexpectedly: use with caution. In the "log-and-abort" mode the
invocation of an unexpected syscall results in a debug handler
being invoked which will log the incident and terminate the
program (without executing the unexpected syscall). In the
"abort" mode the invocation of an unexpected syscall results in
the entire process being killed immediately by the kernel without
executing the unexpected syscall.
```
The allowed syscalls are defined on a per thread basis.
I've used this feature since summer 2020 and I find it to be a helpful testing/debugging addition which makes it much easier to reason about the actual capabilities required of each type of thread in Bitcoin Core.
---
Quick start guide:
```
$ ./configure
$ src/bitcoind -regtest -debug=util -sandbox=log-and-abort
…
2021-06-09T12:34:56Z Experimental syscall sandbox enabled (-sandbox=log-and-abort): bitcoind will terminate if an unexpected (not allowlisted) syscall is invoked.
…
2021-06-09T12:34:56Z Syscall filter installed for thread "addcon"
2021-06-09T12:34:56Z Syscall filter installed for thread "dnsseed"
2021-06-09T12:34:56Z Syscall filter installed for thread "net"
2021-06-09T12:34:56Z Syscall filter installed for thread "msghand"
2021-06-09T12:34:56Z Syscall filter installed for thread "opencon"
2021-06-09T12:34:56Z Syscall filter installed for thread "init"
…
# A simulated execve call to show the sandbox in action:
2021-06-09T12:34:56Z ERROR: The syscall "execve" (syscall number 59) is not allowed by the syscall sandbox in thread "msghand". Please report.
…
Aborted (core dumped)
$
```
---
[About seccomp and seccomp-bpf](https://en.wikipedia.org/wiki/Seccomp):
> In computer security, seccomp (short for secure computing mode) is a facility in the Linux kernel. seccomp allows a process to make a one-way transition into a "secure" state where it cannot make any system calls except exit(), sigreturn(), and read() and write() to already-open file descriptors. Should it attempt any other system calls, the kernel will terminate the process with SIGKILL or SIGSYS. In this sense, it does not virtualize the system's resources but isolates the process from them entirely.
>
> […]
>
> seccomp-bpf is an extension to seccomp that allows filtering of system calls using a configurable policy implemented using Berkeley Packet Filter rules. It is used by OpenSSH and vsftpd as well as the Google Chrome/Chromium web browsers on Chrome OS and Linux. (In this regard seccomp-bpf achieves similar functionality, but with more flexibility and higher performance, to the older systrace—which seems to be no longer supported for Linux.)
ACKs for top commit:
laanwj:
Code review and lightly tested ACK 4747da3a5b
Tree-SHA512: e1c28e323eb4409a46157b7cc0fc29a057ba58d1ee2de268962e2ade28ebd4421b5c2536c64a3af6e9bd3f54016600fec88d016adb49864b63edea51ad838e17
No longer special case a set of warnings, to make up our own -Werror,
just use -Werror outright. This shouldn't really have any effect on
existing builders, who were already using --enable-werror, and is more
inline with what they would expect --enable-werror to be, which is
erroring on any/all warnings.
We keep -Wno-error=return-type because we know that is broken when using
mingw-w64. It should only be applied when cross-compiling for Windows.
Co-authored-by: Hennadii Stepanov <32963518+hebasto@users.noreply.github.com>
It was [pointed out in #23030](https://github.com/bitcoin/bitcoin/pull/23030#issuecomment-922893367) that we might be able to get rid of our weak linking of [`getauxval()`](https://man7.org/linux/man-pages/man3/getauxval.3.html) (`HAVE_WEAK_GETAUXVAL`) entirely, with only Android being a potential holdout:
> I wonder if it's time to get rid of HAVE_WEAK_GETAUXVAL. I think it's confusing. Either we build against a C library that has this functionality, or not. We don't do this weak linking thing for any other symbols and recently got rid of the other glibc backwards compatibility stuff.
> Unless there is still a current platform that really needs it (Android?), I'd prefer to remove it from the build system, it has caused enough issues.
After looking at Android further, it would seem that given we are moving to using `std::filesystem`, which [requires NDK version 22 and later](https://github.com/android/ndk/wiki/Changelog-r22), and `getauxval` has been available in the since [API version 18](https://developer.android.com/ndk/guides/cpu-features#features_using_libcs_getauxval3), that shouldn't really be an issue. Support for API levels < 19 will be dropped with the NDK 24 release, and according to [one website](https://apilevels.com/), supporting API level 18+ will cover ~99% of devices. Note that in the CI we currently build with NDK version 22 and API level 28.
The other change in this PR is removing the include of headers for ARM intrinsics, from the check for strong `getauxval()` support in configure, as they shouldn't be needed. Including these headers also meant that the check would basically only succeed when building for ARM. This would be an issue if we remove weak linking, as we wouldn't detect `getauxval()` as supported on other platforms. Note that we also use `getauxval()` in our RNG when it's available.
I've checked that with these changes we detect support for strong `getauxval()` on Alpine (muslibc). On Linux, previously we'd be detecting support for weak getauxval(), now we detect strong support. Note that we already require glibc 2.17, and `getauxval()` was introduced in `2.16`.
This is an alternative / supersedes #23030.
`crc32c`'s hardware accelerated code doesn't handle ARM 32-bit at all.
Make the check in `configure.ac` check for this architecture explicitly.
For the release binaries, the current `configure.ac` check happens
to work: it enables it on aarch64 but disables it for armhf. However
some combination of compiler version and settings might ostensibly cause
this check to succeed on armhf (as reported on IRC). So make the 64-bit
platform requirement explicit.
3ec633ef1a build: improve check for ::(w)system (fanquake)
Pull request description:
`AC_DEFINE()` takes `HAVE_STD__SYSTEM || HAVE_WSYSTEM` literally, meaning you
end up with the following in bitcoin-config.h:
```cpp
/* std::system or ::wsystem */
#define HAVE_SYSTEM HAVE_STD__SYSTEM || HAVE_WSYSTEM
```
This works for the preprocessor, because `HAVE_SYSTEM`, is defined, just unusually. Remove this in favor of setting `have_any_system` in either case, given we don't actually use `HAVE_STD__SYSTEM` or `HAVE_WSYSTEM`, and defining `HAVE_SYSTEM` to 1 thereafter.
ACKs for top commit:
laanwj:
Code review ACK 3ec633ef1a
Tree-SHA512: 02c39ba3179136ec1dc28df026b7fa5d732914c85622298ba7ec880f1ae9324208d322a47be451a5c2ff2e165ad1d446bae92e7018db8e517e7ac38fca25a0a3
At this point, or minimum required glibc is implicitly 2.18, due to
thread_local support being enabled by default. However, users can
disable thread_local support to maintain 2.17 ccompat for now, which is
currently done in the Guix build.
fanquake