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v4l2: v4l2_compat: Intercept open64, openat64, and mmap64

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Some applications (eg. Firefox, Google Chrome, Skype) use open64,
openat64, and mmap64 instead of their non-64 versions that we currently
intercept. Intercept these calls as well. _LARGEFILE64_SOURCE needs to
be set so that the 64-bit symbols are available and not synonymous to
the non-64-bit versions on 64-bit systems.

Also, since we set _FILE_OFFSET_BITS to 32 to force the various open and
mmap symbols that we export to not be the 64-bit versions, our dlsym to
get the original open and mmap calls will not automatically be converted
to their 64-bit versions. Since we intercept both 32-bit and 64-bit
versions of open and mmap, we should be using the 64-bit version to
service both. Fetch the 64-bit versions of openat and mmap directly.

musl defines the 64-bit symbols as macros that are equivalent to the
non-64-bit symbols, so we put compile guards that check if the 64-bit
symbols are defined.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> # Compile with musl
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
This commit is contained in:
Paul Elder 2020-06-08 19:36:12 +09:00
parent ee5dc92dc1
commit 1023107b64
6 changed files with 53 additions and 7 deletions
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6
src/v4l2/v4l2_compat_manager.cpp
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@ -39,11 +39,11 @@ void get_symbol(T &func, const char *name)
V4L2CompatManager::V4L2CompatManager()
: cm_(nullptr)
{
get_symbol(fops_.openat, "openat");
get_symbol(fops_.openat, "openat64");
get_symbol(fops_.dup, "dup");
get_symbol(fops_.close, "close");
get_symbol(fops_.ioctl, "ioctl");
get_symbol(fops_.mmap, "mmap");
get_symbol(fops_.mmap, "mmap64");
get_symbol(fops_.munmap, "munmap");
}
@ -200,7 +200,7 @@ int V4L2CompatManager::close(int fd)
}
void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
int fd, off_t offset)
int fd, off64_t offset)
{
V4L2CameraProxy *proxy = getProxy(fd);
if (!proxy)