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| author | bors <bors@rust-lang.org> | 2022-11-30 10:16:44 +0000 |
|---|---|---|
| committer | bors <bors@rust-lang.org> | 2022-11-30 10:16:44 +0000 |
| commit | 855a6fc48ab1634ef01836d6493d08b119bdd424 (patch) | |
| tree | 7a8fd6981919a5471a6b73393645c3d901456e7a | |
| parent | e4b8fd4f59a87346c870295c8125469c672998aa (diff) | |
| parent | 7bbbfb03c45d328f7170b34921f3ede0e9f277c2 (diff) | |
| download | rust-libc-855a6fc48ab1634ef01836d6493d08b119bdd424.tar.gz | |
Auto merge of #3010 - stevenengler:sock-storage-repr, r=JohnTitor
Rearrange `sockaddr_storage` padding/alignment fields on Linux and Fuchsia
Part of #3004.
Previously on Linux, the `sockaddr_storage` structure had padding bytes between the `ss_family` and `__ss_align` fields. The `__ss_align` field has now been moved to the end of the structure to eliminate these padding bytes, matching recent glibc versions: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/bits/socket.h;h=4f1f810ea1d9bf00ff428e4e7c49a52c71620775;hb=c804cd1c00adde061ca51711f63068c103e94eef#l190
After the PR on Linux x86-64:
```
print-type-size type: `unix::linux_like::sockaddr_storage`: 128 bytes, alignment: 8 bytes
print-type-size field `.ss_family`: 2 bytes
print-type-size field `.__ss_pad2`: 118 bytes
print-type-size field `.__ss_align`: 8 bytes
```
These moved fields are private but they are used in the `sockaddr_storage`s `PartialEq`, `Debug`, and `Hash` implementations, so the exact behaviour may change slightly, but I don't think anyone should be depending on this.
~(It looks like [Fuchsia](https://github.com/rust-lang/libc/blob/73c25f4e9d66054d1496c693b72d60caea00c4a9/src/fuchsia/mod.rs#L910) has the same issue, but I didn't modify its structure because I don't know much about it, or how to test it.)~
| -rw-r--r-- | src/fuchsia/mod.rs | 2 | ||||
| -rw-r--r-- | src/unix/linux_like/mod.rs | 6 |
2 files changed, 4 insertions, 4 deletions
diff --git a/src/fuchsia/mod.rs b/src/fuchsia/mod.rs index cc2bcd516b..7a9edada1f 100644 --- a/src/fuchsia/mod.rs +++ b/src/fuchsia/mod.rs @@ -909,8 +909,8 @@ s_no_extra_traits! { pub struct sockaddr_storage { pub ss_family: sa_family_t, + __ss_pad2: [u8; 128 - 2 - 8], __ss_align: ::size_t, - __ss_pad2: [u8; 128 - 2 * 8], } pub struct utsname { diff --git a/src/unix/linux_like/mod.rs b/src/unix/linux_like/mod.rs index 46964cc173..8e738d87b8 100644 --- a/src/unix/linux_like/mod.rs +++ b/src/unix/linux_like/mod.rs @@ -231,11 +231,11 @@ s_no_extra_traits! { pub struct sockaddr_storage { pub ss_family: sa_family_t, - __ss_align: ::size_t, #[cfg(target_pointer_width = "32")] - __ss_pad2: [u8; 128 - 2 * 4], + __ss_pad2: [u8; 128 - 2 - 4], #[cfg(target_pointer_width = "64")] - __ss_pad2: [u8; 128 - 2 * 8], + __ss_pad2: [u8; 128 - 2 - 8], + __ss_align: ::size_t, } pub struct utsname { |