2278327eba
This change makes some miracle modifications to the System Five system call support, which lets us have safe, correct, and atomic handling of thread cancellations. It all turned out to be cheaper than anticipated because it wasn't necessary to modify the system call veneers. We were able to encode the cancellability of each system call into the magnums found in libc/sysv/syscalls.sh. Since cancellations are so waq, we are also supporting a lovely Musl Libc mask feature for raising ECANCELED. |
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|---|---|---|
| .. | ||
| calls | ||
| consts | ||
| dos2errno | ||
| errfuns | ||
| consts.sh | ||
| describeos.greg.c | ||
| dos2errno.sh | ||
| errfun.S | ||
| errfuns.h | ||
| errfuns.sh | ||
| errno.c | ||
| errno_location.greg.c | ||
| gen.sh | ||
| macros.internal.h | ||
| README.md | ||
| restorert.S | ||
| strace.greg.c | ||
| syscall.S | ||
| syscalls.sh | ||
| syscount.S | ||
| systemfive.S | ||
| sysv.mk | ||
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