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musl - an implementation of the standard library for Linux-based systems
POSIX places an obscure requirement on popen which is like a limited version of close-on-exec: "The popen() function shall ensure that any streams from previous popen() calls that remain open in the parent process are closed in the new child process." if the POSIX-future 'e' mode flag is passed, producing a pipe FILE with FD_CLOEXEC on the underlying pipe, this requirement is automatically satisfied. however, for applications which use multiple concurrent popen pipes but don't request close-on-exec, fd leaks from earlier popen calls to later ones could produce deadlock situations where processes are waiting for a pipe EOF that will never happen. to fix this, iterate through all open FILEs and add close actions for those obtained from popen. this requires holding a lock on the open file list across the posix_spawn call so that additional popen FILEs are not created after the list is traversed. note that it's still possible for another popen call to start and create its pipe while the lock is held, but such pipes are created with O_CLOEXEC and only drop close-on-exec status (when 'e' flag is omitted) under control of the lock. |
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arch | ||
compat/time32 | ||
crt | ||
dist | ||
include | ||
ldso | ||
src | ||
tools | ||
.gitignore | ||
.mailmap | ||
configure | ||
COPYRIGHT | ||
dynamic.list | ||
INSTALL | ||
Makefile | ||
README | ||
VERSION | ||
WHATSNEW |
musl libc musl, pronounced like the word "mussel", is an MIT-licensed implementation of the standard C library targetting the Linux syscall API, suitable for use in a wide range of deployment environments. musl offers efficient static and dynamic linking support, lightweight code and low runtime overhead, strong fail-safe guarantees under correct usage, and correctness in the sense of standards conformance and safety. musl is built on the principle that these goals are best achieved through simple code that is easy to understand and maintain. The 1.1 release series for musl features coverage for all interfaces defined in ISO C99 and POSIX 2008 base, along with a number of non-standardized interfaces for compatibility with Linux, BSD, and glibc functionality. For basic installation instructions, see the included INSTALL file. Information on full musl-targeted compiler toolchains, system bootstrapping, and Linux distributions built on musl can be found on the project website: http://www.musl-libc.org/