svn commit: r313947 - head/sys/compat/linux
Edward Tomasz Napierala
trasz at FreeBSD.org
Sun Feb 19 17:17:07 UTC 2017
Author: trasz
Date: Sun Feb 19 17:17:06 2017
New Revision: 313947
URL: https://svnweb.freebsd.org/changeset/base/313947
Log:
There are some Linux binaries that expect the system to obey the "addr"
parameter to mmap(2), even if MAP_FIXED is not explicitly specified.
Android ART is one example. Implement bug compatibility for this case
in linuxulator.
Reviewed by: dchagin@
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9373
Modified:
head/sys/compat/linux/linux_mmap.c
Modified: head/sys/compat/linux/linux_mmap.c
==============================================================================
--- head/sys/compat/linux/linux_mmap.c Sun Feb 19 16:59:00 2017 (r313946)
+++ head/sys/compat/linux/linux_mmap.c Sun Feb 19 17:17:06 2017 (r313947)
@@ -203,8 +203,23 @@ linux_mmap_common(struct thread *td, uin
}
}
- error = kern_mmap(td, addr, len, prot, bsd_flags, fd, pos);
+ /*
+ * FreeBSD is free to ignore the address hint if MAP_FIXED wasn't
+ * passed. However, some Linux applications, like the ART runtime,
+ * depend on the hint. If the MAP_FIXED wasn't passed, but the
+ * address is not zero, try with MAP_FIXED and MAP_EXCL first,
+ * and fall back to the normal behaviour if that fails.
+ */
+ if (addr != 0 && (bsd_flags & MAP_FIXED) == 0 &&
+ (bsd_flags & MAP_EXCL) == 0) {
+ error = kern_mmap(td, addr, len, prot,
+ bsd_flags | MAP_FIXED | MAP_EXCL, fd, pos);
+ if (error == 0)
+ goto out;
+ }
+ error = kern_mmap(td, addr, len, prot, bsd_flags, fd, pos);
+out:
LINUX_CTR2(mmap2, "return: %d (%p)", error, td->td_retval[0]);
return (error);
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