30.07.2023 17:41, Zeni Junker пишет:
I'm running Gentoo ( if that matters) I've tried with version 1.4.0 and latest from git repo and the result is the same. Also, it fails the same way whether I start it as a root or ordinary user ( I've added lines for both in dosemu.usrs file: "username/root c_all" ). So I've compiled it with "debug" option tried to debug it with gdb. Well, this has lead me through the initialization. Thing is in main() (in emu.c - line 394) low_mem_init getc called and it fails. Peeking within it shows that low_mem_init ( init.c) calls alloc_mapping ( line 261), which fails. Peek into alloc_mapping ( file mapping.c) fails in line 419,, when it tries to copy pointer to allocated area to lowmem_base, which is 0 at that point: line 419: " *(char **)(&lowmem_base) = addr; " Since low memory has never been allocated at that point, this causes SIGSEGV. At some point I thought this might be due to some kernel protection etc. Setting in/proc/sys/vm/mmap_min_addr was 65536, so I've reset it to 0 and retried, with the same result. Then I've noticed that lowmem_base gets declared as "char * const lowmem_base" in mapping.c and nothing ever sets it, so it is always 0. Just to doublecheck, I've inspected /proc/proc_id/maps of debugged process and indeed there was nothing mapped at address 0 - all I've seen are high address map areas that one usually gets from mmap in the range 0x7Fxxxxxxxx for various libs etc and 4 mappings of dosemu.bin, also at high adresses. But nothing low, so naturally any acess outside of mapped areas SIGSEGVs. So, my question is, am I missing something ?
Some googling, as usual. It would give you this dosemu2 ebuild: https://gpo.zugaina.org/app-emulation/dosemu2/RDep Or an 1.4.0.8 update for dosemu1. Good that you've found your own solution and got a 20-years-old software working, but you certainly could do it otherwise.
