Date: Thu, 2 Feb 2023 20:10:21 GMT From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 2e1edd04eb01 - main - kboot: For hostfs, return better errors from read, where possible. Message-ID: <202302022010.312KALBP044884@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=2e1edd04eb01bac15628185686cbf615d80de7de commit 2e1edd04eb01bac15628185686cbf615d80de7de Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2023-02-02 20:06:24 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2023-02-02 20:06:31 +0000 kboot: For hostfs, return better errors from read, where possible. Translate the Linux error return from read to a FreeBSD errno. We use a simplified translation: 1-34 are the same between the systems, so any of those will be returned directly. All other errno map to EINVAL. This will suffice for some code that reads /dev/mem in producing the right diagnostic. A fully generalized version is much harder. Linux has a number of errno that don't translate well and has architecture dependent encodings. Avoid this mess with a simple macro for now. Add comment explaining why we use the simple method we do. Sponsored by: Netflix Reviewed by: kevans, andrew Differential Revision: https://reviews.freebsd.org/D38265 --- stand/kboot/host_syscall.h | 10 ++++++++++ stand/kboot/hostfs.c | 5 ++--- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/stand/kboot/host_syscall.h b/stand/kboot/host_syscall.h index 38f0fb04aa95..75394afcde6c 100644 --- a/stand/kboot/host_syscall.h +++ b/stand/kboot/host_syscall.h @@ -206,4 +206,14 @@ ssize_t host_write(int fd, const void *buf, size_t nbyte); host_mmap(0, size, HOST_PROT_READ | HOST_PROT_WRITE, \ HOST_MAP_PRIVATE | HOST_MAP_ANONYMOUS, -1, 0); +/* + * Translate Linux errno to FreeBSD errno. The two system have idenitcal errors + * for 1-34. After that, they differ. Linux also has errno that don't map + * exactly to FreeBSD's errno, plus the Linux errno are arch dependent > + * 34. Since we just need to do this for simple cases, use the simple mapping + * function where -1 to -34 are translated to 1 to 34 and all others are EINVAL. + * Pass the linux return value, which will be the -errno. + */ +#define host_to_stand_errno(e) ((-e) > 34 ? EINVAL : (-e)) + #endif diff --git a/stand/kboot/hostfs.c b/stand/kboot/hostfs.c index 08f532999abe..02afa885d833 100644 --- a/stand/kboot/hostfs.c +++ b/stand/kboot/hostfs.c @@ -112,9 +112,8 @@ hostfs_read(struct open_file *f, void *start, size_t size, size_t *resid) ssize_t sz; sz = host_read(hf->hf_fd, start, size); - if (sz < 0) { - return (EINVAL); - } + if (sz < 0) + return (host_to_stand_errno(sz)); *resid = size - sz; return (0);
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