cosmopolitan/libc
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
..
alg Make fixes, improvements, and chibicc python bindings 2021-10-08 08:41:57 -07:00
bits Make fixes, improvements, and chibicc python bindings 2021-10-08 08:41:57 -07:00
calls Improve memory safety 2021-10-13 17:27:13 -07:00
crt Remove more nonstandard stuff from cosmopolitan.h 2021-03-01 00:18:23 -08:00
dns Improve memory safety 2021-10-13 17:27:13 -07:00
elf Make numerous improvements 2021-09-28 01:52:34 -07:00
fmt Improve memory safety 2021-10-13 17:27:13 -07:00
integral Improve memory safety 2021-10-13 17:27:13 -07:00
intrin Improve memory safety 2021-10-13 17:27:13 -07:00
isystem Implement tree-shaking for Python sources 2021-09-05 01:20:03 -07:00
linux [WIP] Threading (#282) 2021-10-13 11:26:05 -07:00
log Improve memory safety 2021-10-13 17:27:13 -07:00
mem Improve memory safety 2021-10-13 17:27:13 -07:00
nexgen32e Improve memory safety 2021-10-13 17:27:13 -07:00
nt Make fixes, improvements, and chibicc python bindings 2021-10-08 08:41:57 -07:00
ohmyplus Fix link order in cosmopolitan.a 2021-01-16 12:05:41 -08:00
rand Improve memory safety 2021-10-13 17:27:13 -07:00
runtime Improve memory safety 2021-10-13 17:27:13 -07:00
sock Improve memory safety 2021-10-13 17:27:13 -07:00
stdio Improve memory safety 2021-10-13 17:27:13 -07:00
str Improve memory safety 2021-10-13 17:27:13 -07:00
stubs Remove undefined behaviors 2021-05-16 11:16:28 -07:00
sysv Improve memory safety 2021-10-13 17:27:13 -07:00
testlib Improve memory safety 2021-10-13 17:27:13 -07:00
thread Improve memory safety 2021-10-13 17:27:13 -07:00
time Improve memory safety 2021-10-13 17:27:13 -07:00
tinymath Make numerous improvements 2021-09-28 01:52:34 -07:00
unicode Make numerous improvements 2021-09-28 01:52:34 -07:00
x Productionize new APE loader and more 2021-10-02 08:27:03 -07:00
zipos Improve memory safety 2021-10-13 17:27:13 -07:00
assert.h Define assert as an expression 2021-04-01 19:42:02 -07:00
complex.h Make improvements 2020-12-01 03:43:40 -08:00
dce.h Make redbean StoreAsset() work better 2021-05-14 05:44:37 -07:00
disclaimer.inc Improve Libc by making Python work even better 2021-08-18 22:16:23 -07:00
dos.h Mold the redbean binary to minimize page faults 2021-05-03 12:14:13 -07:00
errno.h Improve ZIP filesystem and change its prefix 2021-08-22 01:11:53 -07:00
inttypes.h Initial import 2020-06-15 07:18:57 -07:00
libc.mk [WIP] Threading (#282) 2021-10-13 11:26:05 -07:00
limits.h Remove nonstandard defines from limits.h (#115) 2021-03-08 17:34:44 -08:00
literal.h Initial import 2020-06-15 07:18:57 -07:00
mach.h Perform some minor fixups 2021-03-16 22:19:51 -07:00
macho.internal.h Get Cosmopolitan into releasable state 2020-11-25 08:19:00 -08:00
macros-cpp.internal.inc Get codebase completely working with LLVM 2021-02-09 02:57:32 -08:00
macros.internal.h Make fixes, improvements, and chibicc python bindings 2021-10-08 08:41:57 -07:00
macros.internal.inc Improve signal handling and math 2021-02-25 18:33:33 -08:00
math.h Improve ZIP filesystem and change its prefix 2021-08-22 01:11:53 -07:00
notice.inc Improve Libc by making Python work even better 2021-08-18 22:16:23 -07:00
notice.internal.h Add epoll and do more release readiness changes 2020-11-28 12:01:51 -08:00
paths.h Initial import 2020-06-15 07:18:57 -07:00
README.md Add x86_64-linux-gnu emulator 2020-08-25 04:43:42 -07:00
zip.h Refactor out some duplicated code 2021-08-14 06:17:56 -07:00

SYNOPSIS

Cosmopolitan Standard Library.

OVERVIEW

This directory defines static archives defining functions, like printf(), mmap(), win32, etc. Please note that the Cosmopolitan build configuration doesn't link any C/C++ library dependencies by default, so you still have the flexibility to choose the one provided by your system. If you'd prefer Cosmopolitan, just add $(LIBC) and $(CRT) to your linker arguments.

Your library is compromised of many bite-sized static archives. We use the checkdeps tool to guarantee that the contents of the archives are organized in a logical way that's easy to use with or without our makefile infrastructure, since there's no cyclic dependencies.

The Cosmopolitan Library exports only the most stable canonical system calls for all supported operating systems, regardless of which platform is used for compilation. We polyfill many of the APIs, e.g. read(), write() so they work consistently everywhere while other apis, e.g. CreateWindowEx(), might only work on one platform, in which case they become no-op functions on others.

Cosmopolitan polyfill wrappers will usually use the dollar sign naming convention, so they may be bypassed when necessary. This same convention is used when multiple implementations of string library and other performance-critical function are provided to allow Cosmopolitan to go fast on both old and newer computers.

We take an approach to configuration that relies heavily on the compiler's dead code elimination pass (libc/dce.h). Most of the code is written so that, for example, folks not wanting support for OpenBSD can flip a bit in SUPPORT_VECTOR and that code will be omitted from the build. The same is true for builds that are tuned using -march=native which effectively asks the library to not include runtime support hooks for x86 processors older than what you use.

Please note that, unlike Cygwin or MinGW, Cosmopolitan does not achieve broad support by bolting on a POSIX emulation layer. We do nothing more than (in most cases) stateless API translations that get you 90% of the way there in a fast lightweight manner. We therefore can't address some of the subtle differences, such as the nuances of absolute paths on Windows. Our approach could be compared to something more along the lines of, "the Russians just used a pencil to write in space", versus spending millions researching a pen like NASA.