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Use Linux O_PATH flag for BSD O_SYMLINK
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-2
+6
-1
src/kernel/emulation/linux/fcntl/open.c
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src/kernel/emulation/linux/fcntl/open.c
···
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#ifndef O_DIRECTORY
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# define O_DIRECTORY 0x100000
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#endif
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#ifndef LINUX_O_PATH
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#define LINUX_O_PATH 0x200000
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#endif
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int oflags_bsd_to_linux(int flags);
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···
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linux_flags |= LINUX_O_EXCL;
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if (flags & BSD_O_CLOEXEC)
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linux_flags |= LINUX_O_CLOEXEC;
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if (flags & BSD_O_NOFOLLOW)
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if (flags & BSD_O_NOFOLLOW || flags & BSD_O_SYMLINK)
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linux_flags |= LINUX_O_NOFOLLOW;
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if (flags & BSD_O_DIRECTORY)
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linux_flags |= LINUX_O_DIRECTORY;
···
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linux_flags |= LINUX_O_CLOEXEC;
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if (flags & BSD_O_NOCTTY)
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linux_flags |= LINUX_O_NOCTTY;
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if (flags & BSD_O_SYMLINK)
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linux_flags |= LINUX_O_PATH;
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return linux_flags;
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}
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-1
src/kernel/emulation/linux/fcntl/openat.c
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src/kernel/emulation/linux/fcntl/openat.c
···
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filename = "/dev/null";
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struct vchroot_expand_args vc;
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vc.flags = VCHROOT_FOLLOW;
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vc.flags = (flags & BSD_O_SYMLINK || flags & BSD_O_NOFOLLOW) ? 0 : VCHROOT_FOLLOW;
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vc.dfd = atfd(fd);
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strcpy(vc.path, filename);
···
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if (ret < 0) {
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return errno_linux_to_bsd(ret);
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}
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// when we're given O_SYMLINK, `oflags_bsd_to_linux` translates it into
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// O_NOFOLLOW and O_PATH
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// this is the only way to open the symlink itself on Linux
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// unfortunately, this presents additional challenges
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// only a select few Linux syscalls support O_PATH descriptors, which means
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// that for other syscalls, we either have to check for this and use an
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// `l` variant (e.g. `llistxattr` instead of `listxatrr`) or we're screwed
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ret = LINUX_SYSCALL(__NR_openat, vc.dfd, vc.path, linux_flags, mode);
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if (ret < 0)