Re: [PATCH v5 0/3] posix: Execute file function fixes

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

I believe with latest comments from Paul Eggert I see these patchset is ok 
for master.  So I would like to commit it shortly if no one opposes it.

On 29-02-2016 15:33, Adhemerval Zanella wrote:
> This is an update from my previous patchset with fixes based on previous
> comments.  The differences from previous version are:
> 
> * Small fixes on argument handling in exec{l,p} functions.
> 
> * Change argument handling from using int to ptrdiff_t.
> 
> * Fix argument allocation for script execution.
> 
> * Fix empty argument vector for script execution on execvpe and
>   compatibility code on posix_spawn{p}.
> 
> * Some internal execvpe fixes.
> 
> * Various comment typos and wordings.
> 
> * Assume pipe2 is always available.
> 
> --
> 
> This patchset add some cleanup and fixes for the exec{l,le,lp,vpe}
> general function implementation and fixes long standing bugs for
> posix_spawn{p} on Linux.  It is basically my previous 2 patchset
> for execvpe and posix_spawn{p} along with the execl{e,p} fixes.
> 
> For exe{l,le,lp,vpe} function main difference is using stack allocation
> instead of dynamic one for argument handling.  The main difference from
> previous patch iteration is it does not add any memory stack allocation
> constraints due:
> 
> 1. Current GLIBC logic to limit stack allocation through __MAX_ALLOCA_CUTOFF
>    is arbitrary and does no impose any limit (it does not consider current
>    stack size neither stack size limit).
> 
> 2. Memory allocation constraints associated with the functions make
>    stack allocation the only sane option.  All exec function family are
>    defined to be async-safe, where they can be called either through a
>    signal handler or in vfork child, and they can not really on dynamic
>    memory allocation (either through malloc or directly by mmap).
> 
> The posix_spawn{p} is a new implementation for Linux which aims to
> fix some long-standing bug regarding signal handling.  It also
> tries to avoid dynamic memory allocation by either relying on the
> exec{l,vpe} functions with a dynamic mmap memory region allocate
> to use along with direct created child (using clone syscall).
> 
> Adhemerval Zanella (3):
>   posix: Remove dynamic memory allocation from execl{e,p}
>   posix: execvpe cleanup
>   posix: New Linux posix_spawn{p} implementation
> 
>  ChangeLog                                         |  54 +++
>  include/sched.h                                   |   2 +
>  include/unistd.h                                  |   1 +
>  posix/Makefile                                    |   5 +-
>  posix/execl.c                                     |  68 ++--
>  posix/execle.c                                    |  70 ++--
>  posix/execlp.c                                    |  66 ++--
>  posix/execvpe.c                                   | 253 ++++++--------
>  posix/tst-execvp1.c                               |   6 +-
>  posix/tst-execvp2.c                               |   5 +-
>  posix/tst-execvp3.c                               |   5 +-
>  posix/tst-execvp4.c                               |   6 +-
>  posix/tst-execvpe1.c                              |  20 ++
>  posix/tst-execvpe2.c                              |  20 ++
>  posix/tst-execvpe3.c                              |  20 ++
>  posix/tst-execvpe4.c                              |  20 ++
>  posix/tst-execvpe5.c                              | 157 +++++++++
>  posix/tst-execvpe6.c                              | 150 ++++++++
>  posix/tst-spawn2.c                                |  73 ++++
>  sysdeps/posix/dup.c                               |   2 +-
>  sysdeps/unix/sysv/linux/aarch64/clone.S           |   1 +
>  sysdeps/unix/sysv/linux/alpha/clone.S             |   1 +
>  sysdeps/unix/sysv/linux/arm/clone.S               |   1 +
>  sysdeps/unix/sysv/linux/hppa/clone.S              |   1 +
>  sysdeps/unix/sysv/linux/i386/clone.S              |   1 +
>  sysdeps/unix/sysv/linux/ia64/clone2.S             |   2 +
>  sysdeps/unix/sysv/linux/m68k/clone.S              |   1 +
>  sysdeps/unix/sysv/linux/microblaze/clone.S        |   1 +
>  sysdeps/unix/sysv/linux/mips/clone.S              |   1 +
>  sysdeps/unix/sysv/linux/nios2/clone.S             |   1 +
>  sysdeps/unix/sysv/linux/nptl-signals.h            |  10 +
>  sysdeps/unix/sysv/linux/powerpc/powerpc32/clone.S |   1 +
>  sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S |   1 +
>  sysdeps/unix/sysv/linux/s390/s390-32/clone.S      |   2 +
>  sysdeps/unix/sysv/linux/s390/s390-64/clone.S      |   2 +
>  sysdeps/unix/sysv/linux/sh/clone.S                |   1 +
>  sysdeps/unix/sysv/linux/sparc/sparc32/clone.S     |   1 +
>  sysdeps/unix/sysv/linux/sparc/sparc64/clone.S     |   1 +
>  sysdeps/unix/sysv/linux/spawni.c                  | 401 ++++++++++++++++++++++
>  sysdeps/unix/sysv/linux/tile/clone.S              |   1 +
>  sysdeps/unix/sysv/linux/x86_64/clone.S            |   1 +
>  41 files changed, 1158 insertions(+), 278 deletions(-)
>  create mode 100644 posix/tst-execvpe1.c
>  create mode 100644 posix/tst-execvpe2.c
>  create mode 100644 posix/tst-execvpe3.c
>  create mode 100644 posix/tst-execvpe4.c
>  create mode 100644 posix/tst-execvpe5.c
>  create mode 100644 posix/tst-execvpe6.c
>  create mode 100644 posix/tst-spawn2.c
>  create mode 100644 sysdeps/unix/sysv/linux/spawni.c
>