Messages in this thread Patch in this message | | | Date | Mon, 23 Jan 2012 19:55:43 +0400 | From | Cyrill Gorcunov <> | Subject | Re: [patch 4/4] c/r: prctl: Extend PR_SET_MM to set up more mm_struct entries |
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On Mon, Jan 23, 2012 at 06:20:40PM +0400, Cyrill Gorcunov wrote: > After restore we would like the 'ps' command show the command > line and evironment exactly the same it was at checkpoint time. > > So this additional PR_SET_MM_ allow us to do so. Note that > these members of mm_struct is rather used for output in > procfs, except auxv vector which is used by ld.so mostly. > > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > Cc: Michael Kerrisk <mtk.manpages@gmail.com> > Cc: Kees Cook <keescook@chromium.org> > Cc: Tejun Heo <tj@kernel.org> > Cc: Andrew Vagin <avagin@openvz.org> > Cc: Serge Hallyn <serge.hallyn@canonical.com> > Cc: Pavel Emelyanov <xemul@parallels.com> > Cc: Vasiliy Kulikov <segoon@openwall.com> > Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > Cc: Michael Kerrisk <mtk.manpages@gmail.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > ---
This one is with typo fixed.
Cyrill --- From: Cyrill Gorcunov <gorcunov@openvz.org> Subject: c/r: prctl: Extend PR_SET_MM to set up more mm_struct entries
After restore we would like the 'ps' command show the command line and evironment exactly the same it was at checkpoint time.
So this additional PR_SET_MM_ allow us to do so. Note that these members of mm_struct is rather used for output in procfs, except auxv vector which is used by ld.so mostly.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Serge Hallyn <serge.hallyn@canonical.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Vasiliy Kulikov <segoon@openwall.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> --- include/linux/prctl.h | 5 +++ kernel/sys.c | 73 +++++++++++++++++++++++++++++++------------------- 2 files changed, 51 insertions(+), 27 deletions(-)
Index: linux-2.6.git/include/linux/prctl.h =================================================================== --- linux-2.6.git.orig/include/linux/prctl.h +++ linux-2.6.git/include/linux/prctl.h @@ -113,5 +113,10 @@ # define PR_SET_MM_START_STACK 5 # define PR_SET_MM_START_BRK 6 # define PR_SET_MM_BRK 7 +# define PR_SET_MM_ARG_START 8 +# define PR_SET_MM_ARG_END 9 +# define PR_SET_MM_ENV_START 10 +# define PR_SET_MM_ENV_END 11 +# define PR_SET_MM_AUXV 12 #endif /* _LINUX_PRCTL_H */ Index: linux-2.6.git/kernel/sys.c =================================================================== --- linux-2.6.git.orig/kernel/sys.c +++ linux-2.6.git/kernel/sys.c @@ -1693,17 +1693,25 @@ SYSCALL_DEFINE1(umask, int, mask) } #ifdef CONFIG_CHECKPOINT_RESTORE +static bool vma_flags_mismatch(struct vm_area_struct *vma, + unsigned long required, + unsigned long banned) +{ + return (vma->vm_flags & required) != required || + (vma->vm_flags & banned); +} + static int prctl_set_mm(int opt, unsigned long addr, unsigned long arg4, unsigned long arg5) { unsigned long rlim = rlimit(RLIMIT_DATA); - unsigned long vm_req_flags; - unsigned long vm_bad_flags; struct vm_area_struct *vma; int error = 0; struct mm_struct *mm = current->mm; - if (arg4 | arg5) + if (arg4 && opt != PR_SET_MM_AUXV) + return -EINVAL; + else if (arg4 | arg5) return -EINVAL; if (!capable(CAP_SYS_ADMIN)) @@ -1715,7 +1723,9 @@ static int prctl_set_mm(int opt, unsigne down_read(&mm->mmap_sem); vma = find_vma(mm, addr); - if (opt != PR_SET_MM_START_BRK && opt != PR_SET_MM_BRK) { + if (opt != PR_SET_MM_START_BRK && + opt != PR_SET_MM_BRK && + opt != PR_SET_MM_AUXV) { /* It must be existing VMA */ if (!vma || vma->vm_start > addr) goto out; @@ -1725,11 +1735,8 @@ static int prctl_set_mm(int opt, unsigne switch (opt) { case PR_SET_MM_START_CODE: case PR_SET_MM_END_CODE: - vm_req_flags = VM_READ | VM_EXEC; - vm_bad_flags = VM_WRITE | VM_MAYSHARE; - - if ((vma->vm_flags & vm_req_flags) != vm_req_flags || - (vma->vm_flags & vm_bad_flags)) + if (vma_flags_mismatch(vma, VM_READ | VM_EXEC, + VM_WRITE | VM_MAYSHARE)) goto out; if (opt == PR_SET_MM_START_CODE) @@ -1740,11 +1747,8 @@ static int prctl_set_mm(int opt, unsigne case PR_SET_MM_START_DATA: case PR_SET_MM_END_DATA: - vm_req_flags = VM_READ | VM_WRITE; - vm_bad_flags = VM_EXEC | VM_MAYSHARE; - - if ((vma->vm_flags & vm_req_flags) != vm_req_flags || - (vma->vm_flags & vm_bad_flags)) + if (vma_flags_mismatch(vma, VM_READ | VM_WRITE, + VM_EXEC | VM_MAYSHARE)) goto out; if (opt == PR_SET_MM_START_DATA) @@ -1753,19 +1757,6 @@ static int prctl_set_mm(int opt, unsigne mm->end_data = addr; break; - case PR_SET_MM_START_STACK: - -#ifdef CONFIG_STACK_GROWSUP - vm_req_flags = VM_READ | VM_WRITE | VM_GROWSUP; -#else - vm_req_flags = VM_READ | VM_WRITE | VM_GROWSDOWN; -#endif - if ((vma->vm_flags & vm_req_flags) != vm_req_flags) - goto out; - - mm->start_stack = addr; - break; - case PR_SET_MM_START_BRK: if (addr <= mm->end_data) goto out; @@ -1790,6 +1781,34 @@ static int prctl_set_mm(int opt, unsigne mm->brk = addr; break; + case PR_SET_MM_START_STACK: + case PR_SET_MM_ARG_START: + case PR_SET_MM_ARG_END: + case PR_SET_MM_ENV_START: + case PR_SET_MM_ENV_END: +#ifdef CONFIG_STACK_GROWSUP + if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSUP, 0)) +#else + if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSDOWN, 0)) +#endif + goto out; + if (opt == PR_SET_MM_START_STACK) + mm->start_stack = addr; + else if (opt == PR_SET_MM_ARG_START) + mm->arg_start = addr; + else if (opt == PR_SET_MM_ARG_END) + mm->arg_end = addr; + else if (opt == PR_SET_MM_ENV_START) + mm->env_start = addr; + else if (opt == PR_SET_MM_ENV_END) + mm->env_end = addr; + break; + + case PR_SET_MM_AUXV: + if (arg4 > sizeof(mm->saved_auxv)) + goto out; + error = copy_from_user(mm->saved_auxv, (const void __user *)addr, arg4); + break; default: error = -EINVAL; goto out;
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