Rich Felker
c1e5d243b7
the only place stdio was used here was for reading the ldso path file, taking advantage of getdelim to automatically allocate and resize the buffer. the motivation for use here was that, with shared libraries, stdio is already available anyway and free to use. this has long been a nuisance to users because getdelim's use of realloc here triggered a valgrind bug, but removing it doesn't really fix that; on some archs even calling the valgrind-interposed malloc at this point will crash. the actual motivation for this change is moving towards getting rid of use of application-provided malloc in parts of libc where it would be called with libc-internal locks held, leading to the possibility of deadlock if the malloc implementation doesn't follow unwritten rules about which libc functions are safe for it to call. since getdelim is required to produce a pointer as if by malloc (i.e. that can be passed to reallor or free), it necessarily must use the public malloc. instead of performing a realloc loop as the path file is read, first query its size with fstat and allocate only once. this produces slightly different truncation behavior when racing with writes to a file, but neither behavior is or could be made safe anyway; on a live system, ldso path files should be replaced by atomic rename only. the change should also reduce memory waste.
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/