mirror of
https://github.com/checkpoint-restore/criu.git
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e651a6eba4
We have a, well, issue with how we calculate the vma's mnt_id. Right now get one via criu side file descriptor that it got by opening the /proc/pid/map_files/ link. The problem is that these descriptors are 'merged' or 'borrowed' by adjacent vmas from previous ones. Thus, getting the mnt_id value for each of them makes no sense -- these files are the same. So move this mnt_id getting earlier into vma parsing code. This brings a potential problem -- if we have two adjacent vmas mapping the same inode (dev:ino pair) but living in different mount namespaces -- this check would produce wrong result. "Wrong" from the perspective that on restore correct file would be opened from wrong namespace. I propose to live with it, since this is not worse than the --evasive-devices option, it's _very_ unlikely, but saves a lot of openeings. Note, that in case app switched mount namespace and then mapped some new library (with dlopen) things would work correctly -- new vmas will likely be not adjacent and for different dev:ino. Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
#ifndef __CR_VMA_H__
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#define __CR_VMA_H__
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#include "list.h"
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#include "protobuf/vma.pb-c.h"
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struct vm_area_list {
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struct list_head h;
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unsigned nr;
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unsigned long priv_size; /* nr of pages in private VMAs */
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unsigned long longest; /* nr of pages in longest VMA */
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};
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#define VM_AREA_LIST(name) struct vm_area_list name = { .h = LIST_HEAD_INIT(name.h), .nr = 0, }
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static inline void vm_area_list_init(struct vm_area_list *vml)
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{
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INIT_LIST_HEAD(&vml->h);
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vml->nr = 0;
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vml->priv_size = 0;
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vml->longest = 0;
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}
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struct file_desc;
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struct vma_area {
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struct list_head list;
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VmaEntry *e;
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union {
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struct /* for dump */ {
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union {
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/*
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* These two cannot be assigned at once.
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* The file_fd is an fd for a regular file and
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* the socket_id is the inode number of the
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* mapped (PF_PACKET) socket.
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*/
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int vm_file_fd;
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int vm_socket_id;
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};
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char *aufs_rpath; /* path from aufs root */
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char *aufs_fpath; /* full path from global root */
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/*
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* When several subsequent vmas have the same
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* dev:ino pair all 'tail' ones set this to true
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* and the vmst points to the head's stat buf.
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*/
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bool file_borrowed;
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struct stat *vmst;
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int mnt_id;
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};
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struct /* for restore */ {
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struct file_desc *vmfd;
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unsigned long *page_bitmap; /* existent pages */
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unsigned long *ppage_bitmap; /* parent's existent pages */
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unsigned long premmaped_addr; /* restore only */
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};
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};
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};
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extern struct vma_area *alloc_vma_area(void);
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extern int collect_mappings(pid_t pid, struct vm_area_list *vma_area_list);
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extern void free_mappings(struct vm_area_list *vma_area_list);
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extern bool privately_dump_vma(struct vma_area *vma);
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#define vma_area_is(vma_area, s) vma_entry_is((vma_area)->e, s)
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#define vma_area_len(vma_area) vma_entry_len((vma_area)->e)
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#define vma_entry_is(vma, s) (((vma)->status & (s)) == (s))
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#define vma_entry_len(vma) ((vma)->end - (vma)->start)
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/*
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* vma_premmaped_start() can be used only in restorer.
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* In other cases vma_area->premmaped_addr must be used.
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* This hack is required, because vma_area isn't tranfered in restorer and
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* shmid is used to determing which vma-s are cowed.
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*/
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#define vma_premmaped_start(vma) ((vma)->shmid)
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static inline int in_vma_area(struct vma_area *vma, unsigned long addr)
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{
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return addr >= (unsigned long)vma->e->start &&
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addr < (unsigned long)vma->e->end;
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}
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#endif /* __CR_VMA_H__ */
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