From: Rich Felker Date: Sun, 18 Sep 2011 14:14:37 +0000 (-0400) Subject: overhaul clone syscall wrapping X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=commitdiff_plain;h=3f72cdac73030761120cf32aeef44e7d03e2f1fa overhaul clone syscall wrapping several things are changed. first, i have removed the old __uniclone function signature and replaced it with the "standard" linux __clone/clone signature. this was necessary to expose clone to applications anyway, and it makes it easier to port __clone to new archs, since it's now testable independently of pthread_create. secondly, i have removed all references to the ugly ldt descriptor structure (i386 only) from the c code and pthread structure. in places where it is needed, it is now created on the stack just when it's needed, in assembly code. thus, the i386 __clone function takes the desired thread pointer as its argument, rather than an ldt descriptor pointer, just like on all other sane archs. this should not affect applications since there is really no way an application can use clone with threads/tls in a way that doesn't horribly conflict with and clobber the underlying implementation's use. applications are expected to use clone only for creating actual processes, possibly with new namespace features and whatnot. --- diff --git a/include/sched.h b/include/sched.h index 4d8bd3db..7b3f1600 100644 --- a/include/sched.h +++ b/include/sched.h @@ -31,6 +31,33 @@ int sched_yield(void); #define SCHED_FIFO 1 #define SCHED_RR 2 +#ifdef _GNU_SOURCE +#define CSIGNAL 0x000000ff +#define CLONE_VM 0x00000100 +#define CLONE_FS 0x00000200 +#define CLONE_FILES 0x00000400 +#define CLONE_SIGHAND 0x00000800 +#define CLONE_PTRACE 0x00002000 +#define CLONE_VFORK 0x00004000 +#define CLONE_PARENT 0x00008000 +#define CLONE_THREAD 0x00010000 +#define CLONE_NEWNS 0x00020000 +#define CLONE_SYSVSEM 0x00040000 +#define CLONE_SETTLS 0x00080000 +#define CLONE_PARENT_SETTID 0x00100000 +#define CLONE_CHILD_CLEARTID 0x00200000 +#define CLONE_DETACHED 0x00400000 +#define CLONE_UNTRACED 0x00800000 +#define CLONE_CHILD_SETTID 0x01000000 +#define CLONE_NEWUTS 0x04000000 +#define CLONE_NEWIPC 0x08000000 +#define CLONE_NEWUSER 0x10000000 +#define CLONE_NEWPID 0x20000000 +#define CLONE_NEWNET 0x40000000 +#define CLONE_IO 0x80000000 +int clone (int (*)(void *), void *, int, void *, ...); +#endif + #ifdef __cplusplus } #endif diff --git a/src/internal/pthread_impl.h b/src/internal/pthread_impl.h index 95ec9487..26164d83 100644 --- a/src/internal/pthread_impl.h +++ b/src/internal/pthread_impl.h @@ -22,7 +22,6 @@ struct pthread { struct pthread *self; - unsigned long tlsdesc[4]; pid_t tid, pid; int tsd_used, errno_val, *errno_ptr; volatile uintptr_t cp_sp, cp_ip; @@ -87,7 +86,7 @@ struct __timer { pthread_t __pthread_self_init(void); -int __uniclone(void *, void (*)(pthread_t), void *); +int __clone(int (*)(void *), void *, int, void *, ...); int __set_thread_area(void *); int __libc_sigaction(int, const struct sigaction *, struct sigaction *); int __libc_sigprocmask(int, const sigset_t *, sigset_t *); diff --git a/src/thread/__set_thread_area.c b/src/thread/__set_thread_area.c index f2ac6e97..136be575 100644 --- a/src/thread/__set_thread_area.c +++ b/src/thread/__set_thread_area.c @@ -1,4 +1,4 @@ -#include +#include "pthread_impl.h" int __set_thread_area(void *p) { diff --git a/src/thread/clone.c b/src/thread/clone.c index e69de29b..339e28a3 100644 --- a/src/thread/clone.c +++ b/src/thread/clone.c @@ -0,0 +1,10 @@ +#include +#include "libc.h" + +int __clone(int (*func)(void *), void *stack, int flags, void *arg, ...) +{ + errno = ENOSYS; + return -1; +} + +weak_alias(__clone, clone); diff --git a/src/thread/forkall.c b/src/thread/forkall.c index 403818ec..6810ea50 100644 --- a/src/thread/forkall.c +++ b/src/thread/forkall.c @@ -1,3 +1,4 @@ +#if 0 #include "pthread_impl.h" #include @@ -64,3 +65,4 @@ pid_t forkall() __synccall(do_forkall, &c); return c.pid; } +#endif diff --git a/src/thread/i386/__set_thread_area.s b/src/thread/i386/__set_thread_area.s index a43525ec..cccf1cd3 100644 --- a/src/thread/i386/__set_thread_area.s +++ b/src/thread/i386/__set_thread_area.s @@ -2,20 +2,21 @@ .global __set_thread_area .type __set_thread_area,@function __set_thread_area: - pushl %ebx - movl 8(%esp),%ecx - movl $-1,4(%ecx) - movl %ecx,8(%ecx) - movl $0xfffff,12(%ecx) - movl $0x51,16(%ecx) - leal 4(%ecx),%ebx - movl $243,%eax + push %ebx + push $0x51 + push $0xfffff + push 16(%esp) + push $-1 + mov %esp,%ebx + xor %eax,%eax + mov $243,%al int $128 - popl %ebx testl %eax,%eax jnz 1f - movl 4(%ecx),%ecx + movl (%esp),%ecx leal 3(,%ecx,8),%ecx movw %cx,%gs 1: + addl $16,%esp + popl %ebx ret diff --git a/src/thread/i386/clone.s b/src/thread/i386/clone.s index 7af5f5db..bebf01a3 100644 --- a/src/thread/i386/clone.s +++ b/src/thread/i386/clone.s @@ -1,26 +1,51 @@ .text -.global __uniclone -.type __uniclone,@function -__uniclone: - movl 4(%esp),%ecx - subl $24,%ecx - movl 8(%esp),%eax - movl %eax,16(%ecx) - movl 12(%esp),%eax - movl %eax,24(%ecx) - pushl %ebx - pushl %esi - pushl %edi - pushl %ebp - movl %eax,8(%eax) - leal 20(%eax),%edx - leal 4(%eax),%esi - movl %edx,%edi - movl $0x7d0f00,%ebx - movl $120,%eax - int $128 - popl %ebp - popl %edi - popl %esi - popl %ebx +.global __clone +.weak clone +.type __clone,@function +.type clone,@function +__clone: +clone: + push %ebp + mov %esp,%ebp + push %ebx + push %esi + push %edi + + xor %eax,%eax + push $0x51 + mov %gs,%ax + push $0xfffff + shr $3,%eax + push 28(%ebp) + push %eax + mov $120,%al + + mov 12(%ebp),%ecx + mov 16(%ebp),%ebx + and $-16,%ecx + sub $16,%ecx + mov 20(%ebp),%edi + mov %edi,(%ecx) + mov 24(%ebp),%edx + mov %esp,%esi + mov 32(%ebp),%edi + mov 8(%ebp),%ebp + int $128 + test %eax,%eax + jnz 1f + + mov %ebp,%eax + xor %ebp,%ebp + call *%eax + mov %eax,%ebx + xor %eax,%eax + inc %eax + int $128 + hlt + +1: add $16,%esp + pop %edi + pop %esi + pop %ebx + pop %ebp ret diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index bef25539..f7768d8d 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -52,11 +52,13 @@ void __pthread_do_unregister(struct __ptcb *cb) self->cancelbuf = self->cancelbuf->__next; } -static void start(pthread_t self) +static int start(void *p) { + pthread_t self = p; if (self->unblock_cancel) __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, 8); pthread_exit(self->start(self->start_arg)); + return 0; } #define ROUND(x) (((x)+PAGE_SIZE-1)&-PAGE_SIZE) @@ -115,14 +117,12 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo new->tsd = (void *)tsd; if (attr) new->detached = attr->_a_detach; new->unblock_cancel = self->cancel; - memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc); - new->tlsdesc[1] = (uintptr_t)new; - stack = (void *)((uintptr_t)new-1 & ~(uintptr_t)15); + stack = (void *)new; __synccall_lock(); a_inc(&libc.threads_minus_1); - ret = __uniclone(stack, start, new); + ret = __clone(start, stack, 0x7d8f00, new, &new->tid, new, &new->tid); __synccall_unlock(); diff --git a/src/thread/x86_64/clone.s b/src/thread/x86_64/clone.s index bf128a47..4db081cd 100644 --- a/src/thread/x86_64/clone.s +++ b/src/thread/x86_64/clone.s @@ -1,21 +1,30 @@ -/* Copyright 2011 Nicholas J. Kain, licensed GNU LGPL 2.1 or later */ .text -.global __uniclone -.type __uniclone,@function -/* rdi = child_stack, rsi = start, rdx = pthread_struct */ -__uniclone: - subq $8,%rsp /* pad parent stack to prevent branch later */ - subq $24,%rdi /* grow child_stack */ - mov %rsi,8(%rdi) /* push start onto child_stack as return ptr */ - mov %rdx,0(%rdi) /* push pthread_struct onto child_stack */ - mov %rdx,%r8 /* r8 = tls */ - mov %rdi,%rsi /* rsi = child_stack */ - leaq 40(%rdx),%r10 /* r10 = child_id */ - movl $56,%eax /* clone syscall number */ - movl $0x7d0f00,%edi /* rdi = flags */ - mov %r10,%rdx /* rdx = parent_id */ - syscall /* clone(flags, child_stack, parent_id, - * child_id, tls) */ - pop %rdi /* child stack: restore pthread_struct - * parent stack: undo rsp displacement */ - ret +.global __clone +.weak clone +.type __clone,@function +.type clone,@function +__clone: +clone: + xor %eax,%eax + mov $56,%al + mov %rdi,%r11 + mov %rdx,%rdi + mov %r8,%rdx + mov %r9,%r8 + mov 8(%rsp),%r10 + mov %r11,%r9 + and $-16,%rsi + sub $8,%rsi + mov %rcx,(%rsi) + syscall + test %eax,%eax + jnz 1f + xor %ebp,%ebp + pop %rdi + call *%r9 + mov %eax,%edi + xor %eax,%eax + mov $60,%al + syscall + hlt +1: ret