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author | H.J. Lu <hjl.tools@gmail.com> | 2021-05-12 11:02:47 -0700 |
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committer | H.J. Lu <hjl.tools@gmail.com> | 2021-07-19 07:36:19 -0700 |
commit | 5adb0e14a5cc9e011e58a7aaf193b598ecbd7b07 (patch) | |
tree | 67083b4eab35852ec1495c34b813abe272a8ad26 /sysdeps/unix/sysv/linux/i386 | |
parent | ee5ed99922ca90bcea4a2f9a48a0c9ae4b534ece (diff) | |
download | glibc-5adb0e14a5cc9e011e58a7aaf193b598ecbd7b07.zip glibc-5adb0e14a5cc9e011e58a7aaf193b598ecbd7b07.tar.gz glibc-5adb0e14a5cc9e011e58a7aaf193b598ecbd7b07.tar.bz2 |
i386: Add the clone3 wrapper
extern int clone3 (struct clone_args *__cl_args, size_t __size,
int (*__func) (void *__arg), void *__arg);
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'sysdeps/unix/sysv/linux/i386')
-rw-r--r-- | sysdeps/unix/sysv/linux/i386/clone3.S | 123 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/i386/sysdep.h | 2 |
2 files changed, 125 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/i386/clone3.S b/sysdeps/unix/sysv/linux/i386/clone3.S new file mode 100644 index 0000000..bef3ce0 --- /dev/null +++ b/sysdeps/unix/sysv/linux/i386/clone3.S @@ -0,0 +1,123 @@ +/* The clone3 syscall wrapper. Linux/i386 version. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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 + <https://www.gnu.org/licenses/>. */ + +/* clone3() is even more special than fork() as it mucks with stacks + and invokes a function in the right context after its all over. */ + +#include <sysdep.h> + +/* The userland implementation is: + int clone3 (struct clone_args *cl_args, size_t size, + int (*func)(void *arg), void *arg); + the kernel entry is: + int clone3 (struct clone_args *cl_args, size_t size); + + The parameters are passed on stack from userland: + 16(%esp) arg + 12(%esp) func + 8(%esp) size + 4(%esp) cl_args + (%esp) Return address + + The kernel expects: + eax: system call number + ebx: cl_args + ecx: size + */ + +#define CL_ARGS 4 +#define SIZE 8 +#define FUNC 12 +#define ARG 16 + + .text +ENTRY (__clone3) + /* Sanity check arguments. */ + movl $-EINVAL, %eax + movl CL_ARGS(%esp), %ecx /* No NULL cl_args pointer. */ + testl %ecx, %ecx + jz SYSCALL_ERROR_LABEL + /* Save the function pointer in EDX which is preserved by the + system call. */ + movl FUNC(%esp), %edx /* No NULL function pointer. */ + testl %edx, %edx + jz SYSCALL_ERROR_LABEL + + /* Save EBX and ESI. */ + pushl %ebx + cfi_adjust_cfa_offset (4) + pushl %esi + cfi_adjust_cfa_offset (4) + + /* Save the function argument in ESI which is preserved by the + system call. */ + movl (ARG + 8)(%esp), %esi + + /* Put cl_args in EBX. */ + movl %ecx, %ebx + + /* Put size in ECX. */ + movl (SIZE + 8)(%esp), %ecx + + /* Do the system call. */ + movl $SYS_ify(clone3), %eax + + /* End FDE now, because in the child the unwind info will be + wrong. */ + cfi_endproc + + int $0x80 + test %eax, %eax + /* No need to restore EBX and ESI in child. */ + jz L(thread_start) + + /* Restore EBX and ESI in parent. */ + pop %esi + pop %ebx + jl SYSCALL_ERROR_LABEL + + ret + +L(thread_start): + cfi_startproc + /* Clearing frame pointer is insufficient, use CFI. */ + cfi_undefined (eip) + xorl %ebp, %ebp /* Terminate the stack frame. */ + + /* Align stack to 16 bytes per the i386 psABI. */ + andl $-16, %esp + + /* The PUSH below will decrement stack pointer by 4 bytes. */ + subl $12, %esp + + /* Set up the argument for the function call. */ + pushl %esi /* Argument. */ + cfi_adjust_cfa_offset (4) + call *%edx /* Call function. */ + + /* Call exit with return value from function call. */ + movl %eax, %ebx + movl $SYS_ify(exit), %eax + ENTER_KERNEL + cfi_endproc + + cfi_startproc +PSEUDO_END (__clone3) + +libc_hidden_def (__clone3) +weak_alias (__clone3, clone3) diff --git a/sysdeps/unix/sysv/linux/i386/sysdep.h b/sysdeps/unix/sysv/linux/i386/sysdep.h index 8680b49..3927a1a 100644 --- a/sysdeps/unix/sysv/linux/i386/sysdep.h +++ b/sysdeps/unix/sysv/linux/i386/sysdep.h @@ -291,6 +291,8 @@ struct libc_do_syscall_args # define HAVE_TIME_VSYSCALL "__vdso_time" # define HAVE_CLOCK_GETRES_VSYSCALL "__vdso_clock_getres" +# define HAVE_CLONE3_WAPPER 1 + # undef HAVE_INTERNAL_BRK_ADDR_SYMBOL # define HAVE_INTERNAL_BRK_ADDR_SYMBOL 1 |