diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/unix/sysv/linux/createthread.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/createthread.c b/sysdeps/unix/sysv/linux/createthread.c new file mode 100644 index 0000000000..7b05d48954 --- /dev/null +++ b/sysdeps/unix/sysv/linux/createthread.c @@ -0,0 +1,154 @@ +/* Low-level thread creation for NPTL. Linux version. + Copyright (C) 2002-2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <sched.h> +#include <setjmp.h> +#include <signal.h> +#include <stdlib.h> +#include <atomic.h> +#include <ldsodefs.h> +#include <tls.h> +#include <stdint.h> + +#include <arch-fork.h> + + +#ifndef ARCH_CLONE +# define ARCH_CLONE __clone +#endif + +/* See the comments in pthread_create.c for the requirements for these + two macros and the create_thread function. */ + +#define START_THREAD_DEFN \ + static int __attribute__ ((noreturn)) start_thread (void *arg) +#define START_THREAD_SELF arg + +/* pthread_create.c defines this using START_THREAD_DEFN + We need a forward declaration here so we can take its address. */ +static int start_thread (void *arg) __attribute__ ((noreturn)); + +static int +create_thread (struct pthread *pd, const struct pthread_attr *attr, + bool stopped_start, STACK_VARIABLES_PARMS, bool *thread_ran) +{ + /* Determine whether the newly created threads has to be started + stopped since we have to set the scheduling parameters or set the + affinity. */ + if (attr != NULL + && (__glibc_unlikely (attr->cpuset != NULL) + || __glibc_unlikely ((attr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0))) + stopped_start = true; + + pd->stopped_start = stopped_start; + if (__glibc_unlikely (stopped_start)) + /* We make sure the thread does not run far by forcing it to get a + lock. We lock it here too so that the new thread cannot continue + until we tell it to. */ + lll_lock (pd->lock, LLL_PRIVATE); + + /* We rely heavily on various flags the CLONE function understands: + + CLONE_VM, CLONE_FS, CLONE_FILES + These flags select semantics with shared address space and + file descriptors according to what POSIX requires. + + CLONE_SIGHAND, CLONE_THREAD + This flag selects the POSIX signal semantics and various + other kinds of sharing (itimers, POSIX timers, etc.). + + CLONE_SETTLS + The sixth parameter to CLONE determines the TLS area for the + new thread. + + CLONE_PARENT_SETTID + The kernels writes the thread ID of the newly created thread + into the location pointed to by the fifth parameters to CLONE. + + Note that it would be semantically equivalent to use + CLONE_CHILD_SETTID but it is be more expensive in the kernel. + + CLONE_CHILD_CLEARTID + The kernels clears the thread ID of a thread that has called + sys_exit() in the location pointed to by the seventh parameter + to CLONE. + + The termination signal is chosen to be zero which means no signal + is sent. */ + const int clone_flags = (CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SYSVSEM + | CLONE_SIGHAND | CLONE_THREAD + | CLONE_SETTLS | CLONE_PARENT_SETTID + | CLONE_CHILD_CLEARTID + | 0); + + TLS_DEFINE_INIT_TP (tp, pd); + + if (__glibc_unlikely (ARCH_CLONE (&start_thread, STACK_VARIABLES_ARGS, + clone_flags, pd, &pd->tid, tp, &pd->tid) + == -1)) + return errno; + + /* It's started now, so if we fail below, we'll have to cancel it + and let it clean itself up. */ + *thread_ran = true; + + /* Now we have the possibility to set scheduling parameters etc. */ + if (attr != NULL) + { + INTERNAL_SYSCALL_DECL (err); + int res; + + /* Set the affinity mask if necessary. */ + if (attr->cpuset != NULL) + { + assert (stopped_start); + + res = INTERNAL_SYSCALL (sched_setaffinity, err, 3, pd->tid, + attr->cpusetsize, attr->cpuset); + + if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))) + err_out: + { + /* The operation failed. We have to kill the thread. + We let the normal cancellation mechanism do the work. */ + + INTERNAL_SYSCALL_DECL (err2); + (void) INTERNAL_SYSCALL (tgkill, err2, 3, + THREAD_GETMEM (THREAD_SELF, pid), + pd->tid, SIGCANCEL); + + return INTERNAL_SYSCALL_ERRNO (res, err); + } + } + + /* Set the scheduling parameters. */ + if ((attr->flags & ATTR_FLAG_NOTINHERITSCHED) != 0) + { + assert (stopped_start); + + res = INTERNAL_SYSCALL (sched_setscheduler, err, 3, pd->tid, + pd->schedpolicy, &pd->schedparam); + + if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err))) + goto err_out; + } + } + + return 0; +} |