af7bd80430
This change introduces a new deadlock detector for Cosmo's POSIX threads implementation. Error check mutexes will now track a DAG of nested locks and report EDEADLK when a deadlock is theoretically possible. These will occur rarely, but it's important for production hardening your code. You don't even need to change your mutexes to use the POSIX error check mode because `cosmocc -mdbg` will enable error checking on mutexes by default globally. When cycles are found, an error message showing your demangled symbols describing the strongly connected component are printed and then the SIGTRAP is raised, which means you'll also get a backtrace if you're using ShowCrashReports() too. This new error checker is so low-level and so pure that it's able to verify the relationships of every libc runtime lock, including those locks upon which the mutex implementation depends. |
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| .. | ||
| calls | ||
| consts | ||
| dos2errno | ||
| errfuns | ||
| BUILD.mk | ||
| consts.sh | ||
| describeos.greg.c | ||
| dos2errno.sh | ||
| errfun.S | ||
| errfun2.c | ||
| errfuns.h | ||
| errfuns.sh | ||
| errno.c | ||
| gen.sh | ||
| hostos.S | ||
| macros.internal.h | ||
| README.md | ||
| restorert.S | ||
| strace.greg.c | ||
| syscall2.S | ||
| syscall3.S | ||
| syscall4.S | ||
| syscalls.sh | ||
| syscon.S | ||
| syscount.S | ||
| syslib.S | ||
| sysret.c | ||
| systemfive.S | ||
| sysv.c | ||
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