If 'e' is used, the kernel must support the recently added pipe2() system
call.
The use of pipe2() with O_CLOEXEC also fixes race conditions between
concurrent popen() calls from different threads, even if the close-on-exec
flag on the fd of the returned FILE is later cleared (because popen() closes
all file descriptors from earlier popen() calls in the child process).
Therefore, this approach should be used in all cases when pipe2() can be
assumed present.
The old version of popen() rejects "re" and "we" but treats "r+e" like "r+".
clang on head between r239347 and r245428.
The former revision introduced CLOCK_PROCESS_CPUTIME_ID as a clock id
for the clock_gettime() function and friends, but it was only added in
<sys/time.h>, not in <time.h>. Any program including <time.h> would
therefore not be able to use CLOCK_PROCESS_CPUTIME_ID, even though the
value of _POSIX_CPUTIME indicates its existence. The latter revision
synchronized the defines again.
Work around this problem by defining the id on the command line for the
particular .cpp file that needs it. If the id ever changes value, this
hack will need to be updated.
The ability to clear a file descriptor's close-on-exec flag via
posix_spawn_file_actions_adddup2() is in fact proposed in Austin Group issue
#411.
MFC after: 1 week
As per POSIX.1-2008, posix_spawn_file_actions_add* return [EBADF] if a file
descriptor is negative, not [EINVAL]. The bug was only in the manual page;
the code is correct.
MFC after: 1 week
kernel-based POSIX semaphore descriptors to userland via procstat(1) and
fstat(1):
- Change sem file descriptors to track the pathname they are associated
with and add a ksem_info() method to copy the path out to a
caller-supplied buffer.
- Use the fo_stat() method of shared memory objects and ksem_info() to
export the path, mode, and value of a semaphore via struct kinfo_file.
- Add a struct semstat to the libprocstat(3) interface along with a
procstat_get_sem_info() to export the mode and value of a semaphore.
- Teach fstat about semaphores and to display their path, mode, and value.
MFC after: 2 weeks
There is no point in hiding, e.g. pmc.xscale(3) from a developer running
on amd64, when the target arch in question will probably never have
manual pages installed at all.
Reviewed by: sbruno, hiren
The pipe2() function is similar to pipe() but allows setting FD_CLOEXEC and
O_NONBLOCK (on both sides) as part of the function.
If p points to two writable ints, pipe2(p, 0) is equivalent to pipe(p).
If the pointer is not valid, behaviour differs: pipe2() writes into the
array from the kernel like socketpair() does, while pipe() writes into the
array from an architecture-specific assembler wrapper.
Reviewed by: kan, kib
The accept4() function, compared to accept(), allows setting the new file
descriptor atomically close-on-exec and explicitly controlling the
non-blocking status on the new socket. (Note that the latter point means
that accept() is not equivalent to any form of accept4().)
The linuxulator's accept4 implementation leaves a race window where the new
file descriptor is not close-on-exec because it calls sys_accept(). This
implementation leaves no such race window (by using falloc() flags). The
linuxulator could be fixed and simplified by using the new code.
Like accept(), accept4() is async-signal-safe, a cancellation point and
permitted in capability mode.
that the method is not supported, return an empty string.
This looks more handy for callers like procstat(1), which will not
abort after the failed call and still output some useful information.
MFC after: 3 weeks
!defined(LIBRARIES_ONLY) so it is only created once on architectures
with 32-bit compat support.
Replace ln -fhs with ${INSTALL_SYMLINK} to the link is logged in the
METALOG.
is a bit obfuscated here, as ia64 adds string source files elsewhere, so
simply exclude it here.
Reviewed by: imp
MFC after: 3 days
Sponsored by: DARPA, AFRL
Trim two now-unneeded (and likely harmful) lines from the libstand
setjmp/longjmp for MIPS.
Spotted by: jmallett
MFC after: 3 days
Sponsored by: DARPA, AFRL
Clang only supports atomic operations for ARMv6. For non-ARMv6, we still
need to emit these functions.
Clang's prototype for these functions slightly differs, as it is truly
based on GCC's documentation. It requires the use of signed types, but
also requires varargs. Still, we are not allowed to simply implement
this function directly. Cleverly work around this by implementing it
under a different name and using __strong_reference().
These APIs were relevant when memory for virtual machine allocation was
hard partitioned away from the rest of the system but that is no longer
the case. The sysctls that provided this information were garbage collected
a while back.
Obtained from: NetApp
