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https://github.com/checkpoint-restore/criu.git
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2c65748f74
/proc/PID/map_files are protected by the global CAP_SYS_ADMIN, so we need to avoid using them to support user namespaces. We are going to use memfd_create() to get the first file descriptor and then all others processes will able to open it via /proc/PID/fd/X. This patch reworks slave processes to not use map_files. v2: add more comments Signed-off-by: Andrey Vagin <avagin@openvz.org> Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
#ifndef __CR_SHMEM_H__
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#define __CR_SHMEM_H__
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#include "lock.h"
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#include "protobuf/vma.pb-c.h"
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/*
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* pid is a pid of a creater
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* start, end are used for open mapping
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* fd is a file discriptor, which is valid for creater,
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* it's opened in cr-restor, because pgoff may be non zero
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*/
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struct shmem_info {
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unsigned long shmid;
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unsigned long start;
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unsigned long end;
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unsigned long size;
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int pid;
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int fd;
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/*
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* 0. lock is initilized to zero
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* 1. the master opens a descriptor and set lock to 1
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* 2. slaves open their descriptors and increment lock
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* 3. the master waits all slaves on lock. After that
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* it can close the descriptor.
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*/
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futex_t lock;
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/*
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* Here is a problem, that we don't know, which process will restore
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* an region. Each time when we found a process with a smaller pid,
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* we reset self_count, so we can't have only one counter.
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*/
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int count; /* the number of regions */
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int self_count; /* the number of regions, which belongs to "pid" */
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};
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struct _VmaEntry;
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extern int collect_shmem(int pid, struct _VmaEntry *vi);
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extern int prepare_shmem_restore(void);
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extern void show_saved_shmems(void);
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extern int get_shmem_fd(int pid, VmaEntry *vi);
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extern unsigned long nr_shmems;
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extern unsigned long rst_shmems;
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extern int cr_dump_shmem(void);
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extern int add_shmem_area(pid_t pid, VmaEntry *vma);
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static always_inline struct shmem_info *
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find_shmem(struct shmem_info *shmems, int nr, unsigned long shmid)
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{
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struct shmem_info *si;
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int i;
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for (i = 0, si = shmems; i < nr; i++, si++)
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if (si->shmid == shmid)
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return si;
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return NULL;
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}
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#endif /* __CR_SHMEM_H__ */
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