diff options
author | Adrian Kummerlaender | 2016-02-20 22:30:11 +0100 |
---|---|---|
committer | Adrian Kummerlaender | 2016-02-20 22:30:11 +0100 |
commit | b3ef0fc8daa41e433f1919a4933a1cc047f59341 (patch) | |
tree | b551c34e381d6df29334848d6aff242c14b69817 /src/actual.h | |
parent | ee51dc19c859e718280bebae1c089be058737b1c (diff) | |
download | change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.tar change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.tar.gz change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.tar.bz2 change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.tar.lz change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.tar.xz change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.tar.zst change-b3ef0fc8daa41e433f1919a4933a1cc047f59341.zip |
Interpose `open` library function
`open` is not as side effect free as I had imagined - i.e. if the flag `O_TRUNC` is passed it truncates the file contents alongside opening the file descriptor. In practice this is done by _emacs_ prior to writing the new file content and as such needs to be intercepted so we can start tracking the file before it is changed.
Interposing `open` required some changes to make the library work without including `fcntl.h`. This header not only defines some of the flags we require to check if a library call actually is able to change files but also defines the `open` library function.
While implementing this change I noticed that the function interpositions implemented in C++ actually need to be declared as `external "C"` so their names do not get wrangled during compilation. I suspect that this was previously implicitly done for e.g. `mmap` and `write` by the included C standard library headers. However this did not work for `open` which is why all function interpositions are now explicitly declared external.
End result: _emacs_ file changes are now tracked correctly.
Diffstat (limited to 'src/actual.h')
-rw-r--r-- | src/actual.h | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/src/actual.h b/src/actual.h index a860590..ae951b9 100644 --- a/src/actual.h +++ b/src/actual.h @@ -6,9 +6,6 @@ #endif #include <dlfcn.h> -#include <sys/mman.h> -#include <sys/uio.h> - #include <memory> #include <cstring> |