Impl new API std::os::unix::fs::mkfifo under feature unix_fifo

[NobodyXu]

Tracking issue #139324

[rustbot]

r? @tgross35

rustbot has assigned @tgross35.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

[rust-log-analyzer]

The job x86_64-gnu-llvm-19 failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

#19 exporting to docker image format
#19 sending tarball 20.2s done
#19 DONE 32.9s
##[endgroup]
Setting extra environment values for docker:  --env ENABLE_GCC_CODEGEN=1 --env GCC_EXEC_PREFIX=/usr/lib/gcc/
[CI_JOB_NAME=x86_64-gnu-llvm-19]
[CI_JOB_NAME=x86_64-gnu-llvm-19]
debug: `DISABLE_CI_RUSTC_IF_INCOMPATIBLE` configured.
---
sccache: Listening on address 127.0.0.1:4226
##[group]Configure the build
configure: processing command line
configure: 
configure: build.configure-args := ['--build=x86_64-unknown-linux-gnu', '--llvm-root=/usr/lib/llvm-19', '--enable-llvm-link-shared', '--set', 'rust.randomize-layout=true', '--set', 'rust.thin-lto-import-instr-limit=10', '--set', 'build.print-step-timings', '--enable-verbose-tests', '--set', 'build.metrics', '--enable-verbose-configure', '--enable-sccache', '--disable-manage-submodules', '--enable-locked-deps', '--enable-cargo-native-static', '--set', 'rust.codegen-units-std=1', '--set', 'dist.compression-profile=balanced', '--dist-compression-formats=xz', '--set', 'rust.lld=false', '--disable-dist-src', '--release-channel=nightly', '--enable-debug-assertions', '--enable-overflow-checks', '--enable-llvm-assertions', '--set', 'rust.verify-llvm-ir', '--set', 'rust.codegen-backends=llvm,cranelift,gcc', '--set', 'llvm.static-libstdcpp', '--enable-new-symbol-mangling']
configure: build.build          := x86_64-unknown-linux-gnu
configure: target.x86_64-unknown-linux-gnu.llvm-config := /usr/lib/llvm-19/bin/llvm-config
configure: llvm.link-shared     := True
configure: rust.randomize-layout := True
configure: rust.thin-lto-import-instr-limit := 10
---
   Compiling addr2line v0.24.2
[RUSTC-TIMING] addr2line test:false 0.278
[RUSTC-TIMING] gimli test:false 2.048
[RUSTC-TIMING] object test:false 2.714
error[E0425]: cannot find function `mkfifo` in module `sys::fs`
    --> library/std/src/os/unix/fs.rs:1134:14
     |
1134 |     sys::fs::mkfifo(path.as_ref(), permissions.mode())
     |              ^^^^^^ not found in `sys::fs`
     |
help: consider importing this function
     |
7    + use libc::mkfifo;
     |
help: if you import `mkfifo`, refer to it directly
     |
1134 -     sys::fs::mkfifo(path.as_ref(), permissions.mode())
1134 +     mkfifo(path.as_ref(), permissions.mode())
     |

For more information about this error, try `rustc --explain E0425`.
[RUSTC-TIMING] std test:false 1.794
error: could not compile `std` (lib) due to 1 previous error

[tgross35]

Maybe "Create a FIFO special file at the specified path..."

[tgross35]

If this test is to be run (I think it's a good idea to have some form of test), it may be better to call mkdtemp and create the FIFO there to ensure it doesn't interfere with anyone who actually has a /tmp/fifo.

[tgross35]

@rustbot author for the failing test and review

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.