220 lines
6.8 KiB
C
220 lines
6.8 KiB
C
/* This file contains some utility routines for PM.
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*
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* The entry points are:
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* find_param: look up a boot monitor parameter
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* get_free_pid: get a free process or group id
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* allowed: see if an access is permitted
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* no_sys: called for invalid system call numbers
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* panic: PM has run aground of a fatal error
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* tell_fs: interface to FS
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* get_mem_map: get memory map of given process
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* get_stack_ptr: get stack pointer of given process
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* proc_from_pid: return process pointer from pid number
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*/
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#include "pm.h"
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#include <sys/stat.h>
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#include <minix/callnr.h>
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#include <minix/com.h>
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#include <fcntl.h>
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#include <signal.h> /* needed only because mproc.h needs it */
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#include "mproc.h"
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#include "param.h"
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#include <minix/config.h>
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#include <timers.h>
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#include <string.h>
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#include "../../kernel/const.h"
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#include "../../kernel/config.h"
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#include "../../kernel/type.h"
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#include "../../kernel/proc.h"
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/*===========================================================================*
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* get_free_pid *
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*===========================================================================*/
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PUBLIC pid_t get_free_pid()
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{
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static pid_t next_pid = INIT_PID + 1; /* next pid to be assigned */
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register struct mproc *rmp; /* check process table */
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int t; /* zero if pid still free */
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/* Find a free pid for the child and put it in the table. */
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do {
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t = 0;
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next_pid = (next_pid < NR_PIDS ? next_pid + 1 : INIT_PID + 1);
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for (rmp = &mproc[0]; rmp < &mproc[NR_PROCS]; rmp++)
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if (rmp->mp_pid == next_pid || rmp->mp_procgrp == next_pid) {
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t = 1;
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break;
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}
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} while (t); /* 't' = 0 means pid free */
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return(next_pid);
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}
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/*===========================================================================*
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* allowed *
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*===========================================================================*/
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PUBLIC int allowed(name_buf, s_buf, mask)
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char *name_buf; /* pointer to file name to be EXECed */
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struct stat *s_buf; /* buffer for doing and returning stat struct*/
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int mask; /* R_BIT, W_BIT, or X_BIT */
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{
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/* Check to see if file can be accessed. Return EACCES or ENOENT if the access
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* is prohibited. If it is legal open the file and return a file descriptor.
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*/
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int fd;
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int save_errno;
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/* Use the fact that mask for access() is the same as the permissions mask.
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* E.g., X_BIT in <minix/const.h> is the same as X_OK in <unistd.h> and
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* S_IXOTH in <sys/stat.h>. tell_fs(DO_CHDIR, ...) has set PM's real ids
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* to the user's effective ids, so access() works right for setuid programs.
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*/
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if (access(name_buf, mask) < 0) return(-errno);
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/* The file is accessible but might not be readable. Make it readable. */
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tell_fs(SETUID, PM_PROC_NR, (int) SUPER_USER, (int) SUPER_USER);
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/* Open the file and fstat it. Restore the ids early to handle errors. */
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fd = open(name_buf, O_RDONLY | O_NONBLOCK);
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save_errno = errno; /* open might fail, e.g. from ENFILE */
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tell_fs(SETUID, PM_PROC_NR, (int) mp->mp_effuid, (int) mp->mp_effuid);
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if (fd < 0) return(-save_errno);
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if (fstat(fd, s_buf) < 0) panic(__FILE__,"allowed: fstat failed", NO_NUM);
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/* Only regular files can be executed. */
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if (mask == X_BIT && (s_buf->st_mode & I_TYPE) != I_REGULAR) {
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close(fd);
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return(EACCES);
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}
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return(fd);
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}
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/*===========================================================================*
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* no_sys *
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*===========================================================================*/
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PUBLIC int no_sys()
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{
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/* A system call number not implemented by PM has been requested. */
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return(EINVAL);
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}
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/*===========================================================================*
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* panic *
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*===========================================================================*/
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PUBLIC void panic(who, mess, num)
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char *who; /* who caused the panic */
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char *mess; /* panic message string */
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int num; /* number to go with it */
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{
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/* An unrecoverable error has occurred. Panics are caused when an internal
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* inconsistency is detected, e.g., a programming error or illegal value of a
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* defined constant. The process manager decides to shut down. This results
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* in a HARD_STOP notification to all system processes to allow local cleanup.
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*/
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printf("PM panic (%s): %s", who, mess);
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if (num != NO_NUM) printf(": %d",num);
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printf("\n");
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sys_abort(RBT_PANIC);
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}
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/*===========================================================================*
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* tell_fs *
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*===========================================================================*/
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PUBLIC void tell_fs(what, p1, p2, p3)
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int what, p1, p2, p3;
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{
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/* This routine is only used by PM to inform FS of certain events:
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* tell_fs(CHDIR, slot, dir, 0)
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* tell_fs(EXEC, proc, 0, 0)
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* tell_fs(EXIT, proc, 0, 0)
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* tell_fs(FORK, parent, child, pid)
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* tell_fs(SETGID, proc, realgid, effgid)
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* tell_fs(SETSID, proc, 0, 0)
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* tell_fs(SETUID, proc, realuid, effuid)
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* tell_fs(UNPAUSE, proc, signr, 0)
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* tell_fs(STIME, time, 0, 0)
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*/
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message m;
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m.tell_fs_arg1 = p1;
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m.tell_fs_arg2 = p2;
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m.tell_fs_arg3 = p3;
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_taskcall(FS_PROC_NR, what, &m);
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}
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/*==========================================================================*
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* find_param *
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*==========================================================================*/
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PUBLIC char *find_param(name)
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const char *name;
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{
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register const char *namep;
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register char *envp;
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for (envp = (char *) monitor_params; *envp != 0;) {
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for (namep = name; *namep != 0 && *namep == *envp; namep++, envp++)
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;
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if (*namep == '\0' && *envp == '=')
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return(envp + 1);
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while (*envp++ != 0)
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;
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}
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return(NULL);
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}
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/*===========================================================================*
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* get_mem_map *
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*===========================================================================*/
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PUBLIC int get_mem_map(proc_nr, mem_map)
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int proc_nr; /* process to get map of */
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struct mem_map *mem_map; /* put memory map here */
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{
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struct proc p;
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int s;
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if ((s=sys_getproc(&p, proc_nr)) != OK)
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return(s);
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memcpy(mem_map, p.p_memmap, sizeof(p.p_memmap));
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return(OK);
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}
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/*===========================================================================*
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* get_stack_ptr *
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*===========================================================================*/
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PUBLIC int get_stack_ptr(proc_nr, sp)
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int proc_nr; /* process to get sp of */
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vir_bytes *sp; /* put stack pointer here */
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{
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struct proc p;
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int s;
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if ((s=sys_getproc(&p, proc_nr)) != OK)
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return(s);
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*sp = p.p_reg.sp;
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return(OK);
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}
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/*===========================================================================*
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* proc_from_pid *
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*===========================================================================*/
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PUBLIC int proc_from_pid(mp_pid)
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pid_t mp_pid;
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{
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int rmp;
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for (rmp = 0; rmp < NR_PROCS; rmp++)
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if (mproc[rmp].mp_pid == mp_pid)
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return rmp;
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return -1;
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}
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