cosmopolitan/libc/sysv
Justine Tunney 226aaf3547 Improve memory safety
This commit makes numerous refinements to cosmopolitan memory handling.

The default stack size has been reduced from 2mb to 128kb. A new macro
is now provided so you can easily reconfigure the stack size to be any
value you want. Work around the breaking change by adding to your main:

    STATIC_STACK_SIZE(0x00200000);  // 2mb stack

If you're not sure how much stack you need, then you can use:

    STATIC_YOINK("stack_usage_logging");

After which you can `sort -nr o/$MODE/stack.log`. Based on the unit test
suite, nothing in the Cosmopolitan repository (except for Python) needs
a stack size greater than 30kb. There are also new macros for detecting
the size and address of the stack at runtime, e.g. GetStackAddr(). We
also now support sigaltstack() so if you want to see nice looking crash
reports whenever a stack overflow happens, you can put this in main():

    ShowCrashReports();

Under `make MODE=dbg` and `make MODE=asan` the unit testing framework
will now automatically print backtraces of memory allocations when
things like memory leaks happen. Bugs are now fixed in ASAN global
variable overrun detection. The memtrack and asan runtimes also handle
edge cases now. The new tools helped to identify a few memory leaks,
which are fixed by this change.

This change should fix an issue reported in #288 with ARG_MAX limits.
Fixing this doubled the performance of MKDEPS.COM and AR.COM yet again.
2021-10-13 17:27:13 -07:00
..
calls Improve memory safety 2021-10-13 17:27:13 -07:00
consts Improve memory safety 2021-10-13 17:27:13 -07:00
errfuns Remove more nonstandard stuff from cosmopolitan.h 2021-03-01 00:18:23 -08:00
machcalls Productionize new APE loader and more 2021-10-02 08:27:03 -07:00
consts.sh Improve memory safety 2021-10-13 17:27:13 -07:00
errfuns.h Make ANSI mode closer to being ANSI 2021-02-03 17:14:17 -08:00
errfuns.sh Change license 2020-12-27 17:18:44 -08:00
g_syscount.S Remove more nonstandard stuff from cosmopolitan.h 2021-03-01 00:18:23 -08:00
gen.sh Remove more nonstandard stuff from cosmopolitan.h 2021-03-01 00:18:23 -08:00
machcalls.sh Productionize new APE loader and more 2021-10-02 08:27:03 -07:00
macros.internal.h Make improvements 2020-12-01 03:43:40 -08:00
README.md Initial import 2020-06-15 07:18:57 -07:00
restorert.S Improve memory safety 2021-10-13 17:27:13 -07:00
syscall.S Remove more nonstandard stuff from cosmopolitan.h 2021-03-01 00:18:23 -08:00
syscalls.sh Improve memory safety 2021-10-13 17:27:13 -07:00
systemfive.S Improve memory safety 2021-10-13 17:27:13 -07:00
sysv.mk Remove more nonstandard stuff from cosmopolitan.h 2021-03-01 00:18:23 -08:00

SYNOPSIS

System Five Import Libraries

OVERVIEW

Bell System Five is the umbrella term we use to describe Linux, FreeBSD, OpenBSD, and Mac OS X which all have nearly-identical application binary interfaces that stood the test of time, having definitions nearly the same as those of AT&T back in the 1980's.

Cosmopolitan aims to help you build apps that can endure over the course of decades, just like these systems have: without needing to lift a finger for maintenance churn, broken builds, broken hearts.

The challenge to System V binary compatibility basically boils down to numbers. All these systems agree on what services are provided, but tend to grant them wildly different numbers.

We address this by putting all the numbers in a couple big shell scripts, ask the GNU Assembler to encode them into binaries using an efficient LEB128 encoding, unpacked by _init(), and ref'd via extern const. It gives us good debuggability, and any costs are gained back by fewer branches in wrapper functions.z