SigSet: A new unsafe helper method to create a SigSet from a sigset_t #1741
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v4:
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I know it's unrelated to this PR, but |
Ooh, good catch. Could you open an issue for this? |
Done |
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Rebase |
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it has been suggested to me that |
1741: SigSet: A new unsafe helper method to create a SigSet from a sigset_t r=rtzoeller a=germag
Currently, the only way to create a `SigSet` from a `sigset_t` object
is by using pointer casts, like:
```
unsafe {
let sigset = *(&sigset as *const libc::sigset_t as *const SigSet)
};
```
This is un-ergonomic for library creators with interfaces to C.
So, let's add a new unsafe method that creates a `SigSet` from a
`libc::sigset_t` object.
We can't implement `From` since converting from `libc::sigset_t` to
`SigSet` is unsafe, because objects of type `libc::sigset_t` must be
initialized by calling either `sigemptyset(3)` or `sigfillset(3)`
before being used. In other case, the results are undefined.
We can't implement `TryFrom` either, because there is no way to check
if an object of type `libc::sigset_t` is initialized.
Signed-off-by: German Maglione <gmaglione@redhat.com>
Co-authored-by: German Maglione <gmaglione@redhat.com>
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Build failed: |
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@germag can you update the commit adding the test to fix the formatting issue, and also fix the typos in the changelog (e.g. in transparent), since we're updating things anyways? |
Currently, the only way to create a `SigSet` from a `sigset_t` object
is by using pointer casts, like:
```
unsafe {
let sigset = *(&sigset as *const libc::sigset_t as *const SigSet)
};
```
This is un-ergonomic for library creators with interfaces to C.
So, let's add a new unsafe method that creates a `SigSet` from a
`libc::sigset_t` object.
We can't implement `From` since converting from `libc::sigset_t` to
`SigSet` is unsafe, because objects of type `libc::sigset_t` must be
initialized by calling either `sigemptyset(3)` or `sigfillset(3)`
before being used. In other case, the results are undefined.
We can't implement `TryFrom` either, because there is no way to check
if an object of type `libc::sigset_t` is initialized.
Signed-off-by: German Maglione <gmaglione@redhat.com>
This commit adds the `repr(transparent)` attribute to the `SigSet` struct, to make sure that its representation is exactly like the `sigset_t` struct from C, in all cases. Signed-off-by: German Maglione <gmaglione@redhat.com>
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v5:
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Done, thanks |
Currently, the only way to create a
SigSetfrom asigset_tobjectis by using pointer casts, like:
This is un-ergonomic for library creators with interfaces to C.
So, let's add a new unsafe method that creates a
SigSetfrom alibc::sigset_tobject.We can't implement
Fromsince converting fromlibc::sigset_ttoSigSetis unsafe, because objects of typelibc::sigset_tmust beinitialized by calling either
sigemptyset(3)orsigfillset(3)before being used. In other case, the results are undefined.
We can't implement
TryFromeither, because there is no way to checkif an object of type
libc::sigset_tis initialized.Signed-off-by: German Maglione gmaglione@redhat.com