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    The following form allows you to view linux man pages.

    Command:

    kcmp

    
    
    
    

    SYNOPSIS

           #include <linux/kcmp.h>
    
           int kcmp(pid_t pid1, pid_t pid2, int type,
                    unsigned long idx1, unsigned long idx2);
    
           Note: There is no glibc wrapper for this system call; see NOTES.
    
    
    

    DESCRIPTION

           The kcmp() system call can be used to check whether the  two  processes
           identified  by  pid1  and  pid2 share a kernel resource such as virtual
           memory, file descriptors, and so on.
    
           The type argument specifies which resource is to be compared in the two
           processes.  It has one of the following values:
    
           KCMP_FILE
                  Check  whether a file descriptor idx1 in the process pid1 refers
                  to the same open file description (see open(2)) as file descrip-
                  tor idx2 in the process pid2.
    
           KCMP_FILES
                  Check  whether  the  process  share  the  same  set of open file
                  descriptors.  The arguments idx1 and idx2 are ignored.
    
           KCMP_FS
                  Check whether the processes share the same  filesystem  informa-
                  tion  (i.e.,  file  mode  creation  mask, working directory, and
                  filesystem root).  The arguments idx1 and idx2 are ignored.
    
           KCMP_IO
                  Check whether the processes share I/O  context.   The  arguments
                  idx1 and idx2 are ignored.
    
           KCMP_SIGHAND
                  Check  whether the processes share the same table of signal dis-
                  positions.  The arguments idx1 and idx2 are ignored.
    
           KCMP_SYSVSEM
                  Check whether the processes share the  same  list  of  System  V
                  semaphore  undo  operations.   The  arguments  idx1 and idx2 are
                  ignored.
    
           KCMP_VM
                  Check whether the processes share the same address  space.   The
                  arguments idx1 and idx2 are ignored.
    
           Note  the  kcmp()  is  not  protected against false positives which may
           occur if tasks are running.  One should stop tasks by  sending  SIGSTOP
           (see  signal(7))  prior  to  inspection with this system call to obtain
           meaningful results.
    
               2   v1 is greater than v2.
    
               3   v1 is not equal to v2, but ordering information is unavailable.
    
           On error, -1 is returned, and errno is set appropriately.
    
           kcmp() was designed to return values suitable  for  sorting.   This  is
           particularly  handy  if  one  needs  to  compare a large number of file
           descriptors.
    
    
    

    ERRORS

           EBADF  type is KCMP_FILE and fd1 or fd2 is not an open file descriptor.
    
           EINVAL type is invalid.
    
           EPERM  Insufficient  permission  to  inspect  process  resources.   The
                  CAP_SYS_PTRACE capability is required to inspect processes  that
                  you do not own.
    
           ESRCH  Process pid1 or pid2 does not exist.
    
    
    

    VERSIONS

           The kcmp() system call first appeared in Linux 3.5.
    
    
    

    CONFORMING TO

           kcmp() is Linux-specific and should not be used in programs intended to
           be portable.
    
    
    

    NOTES

           Glibc does not provide a wrapper for this system call;  call  it  using
           syscall(2).
    
           This  system  call  is available only if the kernel was configured with
           CONFIG_CHECKPOINT_RESTORE.  The main use of the system call is for  the
           checkpoint/restore  in  user  space (CRIU) feature.  The alternative to
           this system call would have been to expose suitable process information
           via  the proc(5) filesystem; this was deemed to be unsuitable for secu-
           rity reasons.
    
           See clone(2) for some background information on  the  shared  resources
           referred to on this page.
    
    
    

    SEE ALSO

           clone(2), unshare(2)
    
    
    

    Linux 2013-12-08 KCMP(2)

    
    
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