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diff --git a/changelogs/changelog.md b/changelogs/changelog.md new file mode 100644 index 000000000..475f568ec --- /dev/null +++ b/changelogs/changelog.md @@ -0,0 +1,31 @@ +# v1.xx.x - yyyy-mm-dd + +## Changes affecting backward compatibility + +## Standard library additions and changes + +### New compile flag (`-d:nimNoGetRandom`) when building `std/sysrand` to remove dependency on linux `getrandom` syscall + +This compile flag only affects linux builds and is necessary if either compiling on a linux kernel version < 3.17, or if code built will be executing on kernel < 3.17. + +On linux kernels < 3.17 (such as kernel 3.10 in RHEL7 and CentOS7), the `getrandom` syscall was not yet introduced. Without this, the `std/sysrand` module will not build properly, and if code is built on a kernel >= 3.17 without the flag, any usage of the `std/sysrand` module will fail to execute on a kernel < 3.17 (since it attempts to perform a syscall to `getrandom`, which isn't present in the current kernel). A compile flag has been added to force the `std/sysrand` module to use /dev/urandom (available since linux kernel 1.3.30), rather than the `getrandom` syscall. This allows for use of a cryptographically secure PRNG, regardless of kernel support for the `getrandom` syscall. + +When building for RHEL7/CentOS7 for example, the entire build process for nim from a source package would then be: +```sh +$ yum install devtoolset-8 # Install GCC version 8 vs the standard 4.8.5 on RHEL7/CentOS7. Alternatively use -d:nimEmulateOverflowChecks. See issue #13692 for details +$ scl enable devtoolset-8 bash # Run bash shell with default toolchain of gcc 8 +$ sh build.sh # per unix install instructions +$ bin/nim c koch # per unix install instructions +$ ./koch boot -d:release # per unix install instructions +$ ./koch tools -d:nimNoGetRandom # pass the nimNoGetRandom flag to compile std/sysrand without support for getrandom syscall +``` + +This is necessary to pass when building nim on kernel versions < 3.17 in particular to avoid an error of "SYS_getrandom undeclared" during the build process for stdlib (sysrand in particular). + +## Language changes + + +## Compiler changes + + +## Tool changes |