now type sema_t is a structure which can be put in a shared memory area,
and multiple processes can operate it concurrently.
User can either use mmap(MAP_SHARED) + sem_init(pshared=1) or use sem_open()
to initialize a shared semaphore.
Named semaphore uses file system and is located in /tmp directory, and its
file name is prefixed with 'SEMD', so now it is chroot or jail friendly.
In simplist cases, both for named and un-named semaphore, userland code
does not have to enter kernel to reduce/increase semaphore's count.
The semaphore is designed to be crash-safe, it means even if an application
is crashed in the middle of operating semaphore, the semaphore state is
still safely recovered by later use, there is no waiter counter maintained
by userland code.
The main semaphore code is in libc and libthr only has some necessary stubs,
this makes it possible that a non-threaded application can use semaphore
without linking to thread library.
Old semaphore implementation is kept libc to maintain binary compatibility.
The kernel ksem API is no longer used in the new implemenation.
Discussed on: threads@
Std 1003.1-2008. Both Linux and Solaris conforms to the new definitions,
so we better follow too (older glibc used old BSDish alphasort prototype
and corresponding type of the comparision function for scandir). While
there, change the definitions of the functions to ANSI C and fix several
style issues nearby.
Remove requirement for "sys/types.h" include for functions from manpage.
POSIX also requires that alphasort(3) sorts as if strcoll(3) was used,
but leave the strcmp(3) call in the function for now.
Adapt in-tree callers of scandir(3) to new declaration. The fact that
select_sections() from catman(1) could modify supplied struct dirent is
a bug.
PR: standards/142255
MFC after: 2 weeks
r195175. Remove all definitions, documentation, and usage.
fifo_misc.c:
Remove all kqueue tests as fifo_io.c performs all those that
would have remained.
Reviewed by: rwatson
MFC after: 3 weeks
X-MFC note: don't change vlan_link_state() function signature
Fix some wrong usages.
Note: this does not affect generated binaries as this argument is not used.
PR: 137213
Submitted by: Eygene Ryabinkin (initial version)
MFC after: 1 month
of setenv(), putenv() and unsetenv() when dealing with corrupt entries in
environ. They now output a warning and complete their task without error.
MFC after: 1 week
instead of returning an error if a corrupt (not a "name=value" string) entry
in the environ array is detected when (re)-building the internal
environment. This should prevent applications or libraries from
experiencing issues arising from the expectation that these calls will
complete even with corrupt entries. The behavior is now as it was prior to
7.0.
Reviewed by: jilles
MFC after: 1 week
find a variable. Include a note that it must not cause the internal
environment to be generated since malloc() depends upon getenv(). To call
malloc() would create a circular dependency.
Recommended by: green
Approved by: jilles
MFC after: 1 week
The maximum length of a username has nothing to do with the size of the
username in the utmp files. Use MAXLOGNAME, which is defined as 17
(UT_USERSIZE + 1).
The entries in the argv array are not const themselves, but sometimes we
want to fill in const values. Just make the array const and use
__DECONST() to make it const for the execve()-call itself.
Also convert the only K&R prototype to ANSI.
Reviewed by: carvay,
the.infamous.paul@gmail.com,
Joan Picanyol i Puig <lists-freebsd-es@biaix.org>,
Ing . Marcos Luis Ortiz Valmaseda <mlortiz@uci.cu>,
eskanete@gmail.com,
Jose M Rodriguez <josemi@freebsd.jazztel.es>,
Guillermo Hernandez <guillermo@QuerySoft.es>,
dani.doni@gmail.com
long instead of an int when examining the results of select() to look for
RPC requests. Previously this routine would ignore RPC requests to sockets
whose file descriptor mod 64 was greater than 31 on a 64-bit platform.
PR: amd64/141130
Submitted by: liujb of array networks
MFC after: 3 days
copied from NetBSD's manpage, and it also matches the behavior
described by the Open Group's online copy of setpgid.2 at
http://www.opengroup.org/onlinepubs/009695399/functions/setpgid.html
Obtained from: NetBSD
Submitted by: Petros Barbayiannis <petrosbarbayiannis@yahoo.gr>
MFC after: 1 week
**environ entries. This puts non-getenv(3) operations in line with
getenv(3) in that bad environ entries do not cause all operations to
fail. There is still some inconsistency in that getenv(3) in the
absence of any environment-modifying operation does not emit corrupt
environ entry warnings.
I also fixed another inconsistency in getenv(3) where updating the
global environ pointer would not be reflected in the return values.
It would have taken an intermediary setenv(3)/putenv(3)/unsetenv(3)
in order to see the change.
execvPe() is called by _execvpe(), which we added to implement
posix_spawnp(). We just took execvP() and added the envp argument.
Unfortunately we forgot to change the implementation to use envp over
environ.
This fixes the following piece of code:
| char * const arg[2] = { "env", NULL };
| char * const env[2] = { "FOO=BAR", NULL };
| posix_spawnp(NULL, "/usr/bin/env", NULL, NULL, arg, env);
MFC after: 2 weeks
FTS_NOCHDIR option is used. fts_build() could strip a trailing slash
from path name in post-order visit if a path pointing to an empty
directory was given for fts_open().
PR: bin/133907, kern/134513
Reviewed by: das
Approved by: trasz (mentor)
MFC after: 1 month
from SUSv4 XSI. Note that the functions are obsoleted, and only
provided to ease porting from System V-like systems. Since sigpause
already exists in compat with different interface, XSI sigpause is
named xsi_sigpause.
Reviewed by: davidxu
MFC after: 3 weeks
and moving the default initialization of prec into the else clause.
The clang static analyzer erroneously thought that nsec can be used
uninitialized here; it was not actually possible, but better to make
the code clearer. (Clang can't know that sprintf() won't modify *pi
behind the scenes.)
uninitialized. Initialize it to a safe value so that there's no
chance of returning an error if stack garbage happens to be equal to
(size_t)-1 or (size_t)-2.
Found by: Clang static analyzer
MFC after: 7 days
a feature that libstdc++ depends on to simulate the behavior of libc's
internal '__isthreaded' variable. One benefit of this is that _libc_once()
is now private to _once_stub.c.
Requested by: kan
