FreeBSD compatibility... #110
Description
Is FreeBSD supported?
The following code snippet leads to a segfault on FreeBSD 14, but works fine on Linux (Ubuntu 24.04 or on Windows/mingw) :
#include "mio/mmap.hpp"
#include <iostream>
#include <system_error>
int main() {
std::error_code err;
mio::mmap_sink mmap;
mmap.map("test/tmp/sharded_filter8.bin", err);
if (err) std::cerr << err.message() << "\n";
std::string tag(15, '\0');
memcpy(tag.data(), mmap.data(), 15);
std::cout << "'" << tag << "'\n";
} precise error (obtained with valgrind):
==3608== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==3608== Bad permissions for mapped region at address 0x4841000
==3608== at 0x203092: main (app/test_mio.cpp:11) // line 11 is the memcpy
I am using mio::access_mode::write because in the original code it is writing and and then reading. If I change it to mmap_source it works fine.
I definitely have read and write permissions to the file, and an earlier instance of mmap_sink could write to the file.
I single stepped through the code, and is correctly opening the file with O_RDWR and passing PROT_WRITE to the ::mmap call.
If I change mmap.ipp:L208 to always pass PROT_READ, it works fine.