fix(simulator): build v4l2_capture as position-independent code - #144
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kern_simulator links with -pie, but the v4l2_capture static library was compiled without -fPIC. On toolchains where GCC is not configured with --enable-default-pie (e.g. Fedora 44), linking with -DSIM_WEBCAM=ON fails: relocation R_X86_64_32 against `.rodata` can not be used when making a PIE object; recompile with -fPIE A static archive is linked object-by-object into the executable, so its relocations must be compatible with a PIR output. The lvgl and wally targets already set POSITION_INDEPENDENT_CODE; v4l2_capture was added later and did not. On Debian/Ubuntu the objects were position independent by compiler default, which masked the problem. Simulator-only change: it does not touch any device code path.
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Problem
The desktop simulator fails to link with
-DSIM_WEBCAM=ONon toolchains where GCC is not configured with--enable-default-pie(reproduced on Fedora 44, GCC 16.1.1):kern_simulatoris linked with-pie(intentional hardening - the simulator parses untrusted input). A static archive is linked object-by-object into the executable, so objects compiled without-fPICcannot be used.v4l2_captuedid not setPOSITION_INDEPENDENT_CODE, so its.textcarried 15 absoluteR_X86_64_PC32.The
lvglandwallytargets already set this property;v4l2_capturewas added later and did not. On Debian/Ubuntu, GCC defaults to PIE, so the objects were position independent by accident and the bug stayed hidden.Change
One line: set
POSITION_INDEPENDENT_CODE ONon thev4l2_capturetarget, matching whatlvglandwallyalready do. Placed after theif(APPLE)/else()block so it covers both the V4L2 and AVFoundation variants.Testing
cmake -B build -S . -DCMAKE_BUILD_TYPE=Debug -DSIM_WEBCAM=ON+ build: links successfully (previously failed).SIM_WEBCAM: unaffected.ctest:storage_smokepasses.Impact
Simulator build system only. No device code path, no firmware build, no change to the simulator/firmware separation. Hardening flags (
-pie,relro,now,noexecstack) are preserved. This makes the build honor than weakening them.