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Android: update pread/pwrite for nullability annotations in NDK 26 #148

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Merged
glessard merged 4 commits into from
Mar 20, 2024
Merged

Android: update pread/pwrite for nullability annotations in NDK 26 #148

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5c3617b
Android: update pread/pwrite for nullability annotations in NDK 26
finagolfin Nov 24, 2023
c2e8f24
avoid passing null pointer to pread() or pwrite()
glessard Jan 5, 2024
1459733
[test] test reading and writing empty, nil-based buffers
glessard Jan 6, 2024
5ca37e7
Android: more targeted approach to unusual nullabilities
glessard Mar 8, 2024
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4 changes: 2 additions & 2 deletions Sources/System/Internals/Syscalls.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ internal func system_pread(
#if ENABLE_MOCKING
if mockingEnabled { return _mockInt(fd, buf, nbyte, offset) }
#endif
return pread(fd, buf, nbyte, offset)
return pread(fd, buf!, nbyte, offset)
}

// lseek
Expand Down Expand Up @@ -101,7 +101,7 @@ internal func system_pwrite(
#if ENABLE_MOCKING
if mockingEnabled { return _mockInt(fd, buf, nbyte, offset) }
#endif
return pwrite(fd, buf, nbyte, offset)
return pwrite(fd, buf!, nbyte, offset)
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@glessard glessard Nov 29, 2023

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I'm afraid we can't do it this way. This pointer comes from a caller-supplied buffer, whose baseAddress could well be nil. For example:

    let fd = FileDescriptor.standardOutput
    let empty = UnsafeRawBufferPointer(start: nil, count: 0)
    let written = try fd.write(toAbsoluteOffset: 0, empty) // crash at runtime with the suggested force-unwrap

We don't have that precise case covered in a test, but we should!

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@finagolfin finagolfin Nov 29, 2023

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OK, I will check it instead.

}

internal func system_dup(_ fd: Int32) -> Int32 {
Expand Down