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	The advantage is that the buffer will always contain the number
of characters as returned from the function, which allows one to use
a sequence like
  /* No more audit module output.  */
  line_length = xgetline (&buffer, &buffer_length, fp);
  TEST_COMPARE_BLOB ("", 0, buffer, line_length);
to check for an expected EOF, while also reporting any unexpected
extra data encountered.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
		
	
		
			
				
	
	
		
			93 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			93 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* Wait for process state.
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   Copyright (C) 2020 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <https://www.gnu.org/licenses/>.  */
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#include <stdlib.h>
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#include <time.h>
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#include <string.h>
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#include <array_length.h>
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#include <support/process_state.h>
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#include <support/xstdio.h>
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#include <support/check.h>
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void
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support_process_state_wait (pid_t pid, enum support_process_state state)
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{
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#ifdef __linux__
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  /* For Linux it does a polling check on /proc/<pid>/status checking on
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     third field.  */
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  /* It mimics the kernel states from fs/proc/array.c  */
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  static const struct process_states
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  {
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    enum support_process_state s;
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    char v;
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  } process_states[] = {
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    { support_process_state_running,      'R' },
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    { support_process_state_sleeping,     'S' },
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    { support_process_state_disk_sleep,   'D' },
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    { support_process_state_stopped,      'T' },
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    { support_process_state_tracing_stop, 't' },
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    { support_process_state_dead,         'X' },
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    { support_process_state_zombie,       'Z' },
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    { support_process_state_parked,       'P' },
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  };
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  char spath[sizeof ("/proc/" + 3) * sizeof (pid_t) + sizeof ("/status") + 1];
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  snprintf (spath, sizeof (spath), "/proc/%i/status", pid);
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  FILE *fstatus = xfopen (spath, "r");
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  char *line = NULL;
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  size_t linesiz = 0;
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  for (;;)
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    {
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      char cur_state = -1;
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      while (xgetline (&line, &linesiz, fstatus) > 0)
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	if (strncmp (line, "State:", strlen ("State:")) == 0)
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	  {
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	    TEST_COMPARE (sscanf (line, "%*s %c", &cur_state), 1);
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	    break;
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	  }
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      /* Fallback to nanosleep for invalid state.  */
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      if (cur_state == -1)
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	break;
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      for (size_t i = 0; i < array_length (process_states); ++i)
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	if (state & process_states[i].s && cur_state == process_states[i].v)
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	  {
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	    free (line);
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	    xfclose (fstatus);
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	    return;
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	  }
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      rewind (fstatus);
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      fflush (fstatus);
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      if (nanosleep (&(struct timespec) { 0, 10000000 }, NULL) != 0)
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	FAIL_EXIT1 ("nanosleep: %m");
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    }
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  free (line);
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  xfclose (fstatus);
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  /* Fallback to nanosleep if an invalid state is found.  */
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#endif
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  nanosleep (&(struct timespec) { 2, 0 }, NULL);
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}
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