47 lines
2.2 KiB
C++
47 lines
2.2 KiB
C++
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// LD_PRELOAD trace shim: intercept EPFramebuffer::swapBuffers in libqsgepaper to
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// learn the exact (contentType, screenMode, flags) the stock app uses for pen
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// strokes. We define functions with the real mangled names so the dynamic loader
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// interposes them, log the args, then chain to the real implementation.
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//
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// QRect is passed by value; its memory layout is {int x1,y1,x2,y2} (l,t,r,b), so
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// we model it as a 16-byte POD to match the ABI without linking Qt. The enums and
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// QFlags are all 4-byte int-sized.
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#include <dlfcn.h>
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#include <cstdio>
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struct RawRect { int x1, y1, x2, y2; };
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extern "C" {
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// swapBuffers(QRect, EPContentType, EPScreenMode, QFlags<UpdateFlag>)
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void _ZN13EPFramebuffer11swapBuffersE5QRect13EPContentType12EPScreenMode6QFlagsINS_10UpdateFlagEE(
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void *self, RawRect r, int contentType, int screenMode, int flags)
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{
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static void (*real)(void *, RawRect, int, int, int) = nullptr;
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if (!real)
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real = (void (*)(void *, RawRect, int, int, int))dlsym(
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RTLD_NEXT,
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"_ZN13EPFramebuffer11swapBuffersE5QRect13EPContentType12EPScreenMode6QFlagsINS_10UpdateFlagEE");
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fprintf(stderr, "SWAPTRACE1 rect=(%d,%d)-(%d,%d) %dx%d content=%d screen=%d flags=%d\n",
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r.x1, r.y1, r.x2, r.y2, r.x2 - r.x1 + 1, r.y2 - r.y1 + 1,
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contentType, screenMode, flags);
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if (real) real(self, r, contentType, screenMode, flags);
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}
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// swapBuffers(const QRegion&, const EPContentMap&, const EPScreenModeMap&, QFlags<UpdateFlag>)
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void _ZN13EPFramebuffer11swapBuffersERK7QRegionRK12EPContentMapRK15EPScreenModeMap6QFlagsINS_10UpdateFlagEE(
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void *self, const void *region, const void *contentMap, const void *modeMap, int flags)
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{
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static void (*real)(void *, const void *, const void *, const void *, int) = nullptr;
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if (!real)
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real = (void (*)(void *, const void *, const void *, const void *, int))dlsym(
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RTLD_NEXT,
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"_ZN13EPFramebuffer11swapBuffersERK7QRegionRK12EPContentMapRK15EPScreenModeMap6QFlagsINS_10UpdateFlagEE");
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fprintf(stderr, "SWAPTRACE2 region=%p contentMap=%p modeMap=%p flags=%d\n",
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region, contentMap, modeMap, flags);
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if (real) real(self, region, contentMap, modeMap, flags);
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}
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} // extern "C"
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