rustc: Fix permission denied error in 'ar' when lto is enabled #17619
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Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @huonw (or someone else) soon. |
| match fs::chmod(&dst, io::UserRead | io::UserWrite) { | ||
| Ok(..) => {} | ||
| Err(e) => { | ||
| sess.err(format!("failed to chmod {}: {}", |
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Maybe this could include some more information, e.g. why the chmod is necessary, and, if possible, what the user can do to fix it? (As a user, I would find it unintuitive that the compiler is trying to chmod a copy of some external crate; specifically mentioning LTO would be a good start, e.g. "failed to chmod {} when preparing for LTO: {}".)
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Looks good, thanks! Just a few little nits and I think this will be ready to meet our integration bot. |
The reason that 'ar' can fail with permission denied is that when link-time optimizations are enabled, rustc copies libraries into a temporary directory, preserving file permissions, and subsequently modifies them using 'ar'. The modification can fail because some package managers may install libraries in system directories as read-only files, which means the temporary file also becomes read-only when it is copied. I have fixed this by giving the temporary file's owner read+write permissions after the copy. I have also added a regression test for this issue.
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@huonw Thanks for the review! I have made the changes you mentioned. If you would like me to change anything else, please let me know. |
The reason that 'ar' can fail with permission denied is that when
link-time optimizations are enabled, rustc copies libraries into a
temporary directory, preserving file permissions, and subsequently
modifies them using 'ar'.
The modification can fail because some package managers may install
libraries in system directories as read-only files, which means the
temporary file also becomes read-only when it is copied.
I have fixed this by giving the temporary file's owner read+write
permissions after the copy.
I have also added a regression test for this issue.