Use posix_spawn_file_actions_adddup2() to clear FD_CLOEXEC.
#1147
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On FreeBSD, OpenBSD, Android, and Glibc ≥ 2.29, `posix_spawn_file_actions_adddup2()` automatically clears `FD_CLOEXEC` if the file descriptors passed to it are equal. Relying on this behaviour eliminates a race condition when spawning child processes. Some older Linuxes (Amazon Linux 2 in particular) don't have this functionality, so we do a runtime check of the Glibc version.
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Confirmed that swift-foundation exit tests still work when running with this branch of swift-testing on Ubuntu 20.04 |
…ntly the case though)
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stmontgomery
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…`. (swiftlang#1147)" This reverts commit 3278217.
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The FreeBSD builds are currently using the GlibC modulemap to import the C runtimes. FreeBSD does not have `gnu_get_libc_version` resulting in build failures. The use of this API was introduced in #1147
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The FreeBSD builds are currently using the GlibC modulemap to import the C runtimes. FreeBSD does not have `gnu_get_libc_version` resulting in build failures. The use of this API was introduced in swiftlang#1147 (cherry picked from commit 79c22ad) - **Explanation**: The FreeBSD builds are currently using the GlibC modulemap to import the C runtimes. FreeBSD does not have `gnu_get_libc_version` resulting in build failures. - **Scope**: Build failure on platforms using Glibc modulemap that don't have GNU extensions. (FreeBSD, OpenBSD) - **Issues**: swiftlang#1193 - **Original PRs**: swiftlang#1183 - **Risk**: Low risk. Removes use of unavailable API. - **Testing**: Built swift-testing on FreeBSD and Linux. - **Reviewers**: @grynspan @3405691582 Fixes: swiftlang#1193
etcwilde
added a commit
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Jul 2, 2025
The FreeBSD builds are currently using the GlibC modulemap to import the C runtimes. FreeBSD does not have `gnu_get_libc_version` resulting in build failures. The use of this API was introduced in #1147 (cherry picked from commit 79c22ad) - **Explanation**: The FreeBSD builds are currently using the GlibC modulemap to import the C runtimes. FreeBSD does not have `gnu_get_libc_version` resulting in build failures. - **Scope**: Build failure on platforms using Glibc modulemap that don't have GNU extensions. (FreeBSD, OpenBSD) - **Issues**: #1193 - **Original PRs**: #1183 - **Risk**: Low risk. Removes use of unavailable API. - **Testing**: Built swift-testing on FreeBSD and Linux. - **Reviewers**: @grynspan @3405691582 Fixes: #1193
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On FreeBSD, OpenBSD, Android, and Glibc ≥ 2.29,
posix_spawn_file_actions_adddup2()automatically clearsFD_CLOEXECif the file descriptors passed to it are equal. Relying on this behaviour eliminates a race condition when spawning child processes. This functionality is standardized in POSIX.1-2024 thanks to Austin Group Defect #411.Some older Linuxes (Amazon Linux 2 in particular) don't have this functionality, so we do a runtime check of the Glibc version.
This PR is a follow-up to #1145.
Resolves #1140.
Checklist: