text: /*
   * Copyright (c) 1995 Peter Wemm <peter@freebsd.org>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, is permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice immediately at the beginning of the file, without modification,
   *    this list of conditions, and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. Absolutely no warranty of function or purpose is made by the author
   *    Peter Wemm.
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD: releng/11.1/lib/libc/gen/setproctitle.c 309275 2016-11-29 01:08:09Z emaste $");
  
  #include "namespace.h"
  #include <sys/param.h>
  #include <sys/exec.h>
  #include <sys/sysctl.h>
  
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include "un-namespace.h"
  
  #include "libc_private.h"
  
  /*
   * Older FreeBSD 2.0, 2.1 and 2.2 had different ps_strings structures and
   * in different locations.
   * 1: old_ps_strings at the very top of the stack.
   * 2: old_ps_strings at SPARE_USRSPACE below the top of the stack.
   * 3: ps_strings at the very top of the stack.
   * We only support a kernel providing #3 style ps_strings.
   *
   * For historical purposes, a definition of the old ps_strings structure
   * and location is preserved below:
  struct old_ps_strings {
  	char	*old_ps_argvstr;
  	int	old_ps_nargvstr;
  	char	*old_ps_envstr;
  	int	old_ps_nenvstr;
  };
  #define	OLD_PS_STRINGS ((struct old_ps_strings *) \
  	(USRSTACK - SPARE_USRSPACE - sizeof(struct old_ps_strings)))
   */
  
  #include <stdarg.h>
  
  #define SPT_BUFSIZE 2048	/* from other parts of sendmail */
  
  void
  setproctitle(const char *fmt, ...)
  {
  	static struct ps_strings *ps_strings;
  	static char *buf = NULL;
  	static char *obuf = NULL;
  	static char **oargv, *kbuf;
  	static int oargc = -1;
  	static char *nargv[2] = { NULL, NULL };
  	char **nargvp;
  	int nargc;
  	int i;
  	va_list ap;
  	size_t len;
  	unsigned long ul_ps_strings;
  	int oid[4];
  
  	if (buf == NULL) {
  		buf = malloc(SPT_BUFSIZE);
  		if (buf == NULL) 
  			return;
  		nargv[0] = buf;
  	}
  
  	if (obuf == NULL ) {
  		obuf = malloc(SPT_BUFSIZE);
  		if (obuf == NULL)
  			return;
  		*obuf = '\0';
  	}
  
  	va_start(ap, fmt);
  
  	if (fmt) {
  		buf[SPT_BUFSIZE - 1] = '\0';
  
  		if (fmt[0] == '-') {
  			/* skip program name prefix */
  			fmt++;
  			len = 0;
  		} else {
  			/* print program name heading for grep */
  			(void)snprintf(buf, SPT_BUFSIZE, "%s: ", _getprogname());
  			len = strlen(buf);
  		}
  
  		/* print the argument string */
  		(void) vsnprintf(buf + len, SPT_BUFSIZE - len, fmt, ap);
  
  		nargvp = nargv;
  		nargc = 1;
  		kbuf = buf;
  	} else if (*obuf != '\0') {
    		/* Idea from NetBSD - reset the title on fmt == NULL */
  		nargvp = oargv;
  		nargc = oargc;
  		kbuf = obuf;
  	} else
  		/* Nothing to restore */
  		return;
  
  	va_end(ap);
  
  	/* Set the title into the kernel cached command line */
  	oid[0] = CTL_KERN;
  	oid[1] = KERN_PROC;
  	oid[2] = KERN_PROC_ARGS;
  	oid[3] = getpid();
  	sysctl(oid, 4, 0, 0, kbuf, strlen(kbuf) + 1);
  
  	if (ps_strings == NULL) {
  		len = sizeof(ul_ps_strings);
  		if (sysctlbyname("kern.ps_strings", &ul_ps_strings, &len, NULL,
  		    0) == -1)
  			return;
  		ps_strings = (struct ps_strings *)ul_ps_strings;
  	}
  
  	/*
  	 * PS_STRINGS points to zeroed memory on a style #2 kernel.
  	 * Should not happen.
  	 */
  	if (ps_strings->ps_argvstr == NULL)
  		return;
  
  	/* style #3 */
  	if (oargc == -1) {
  		/* Record our original args */
  		oargc = ps_strings->ps_nargvstr;
  		oargv = ps_strings->ps_argvstr;
  		for (i = len = 0; i < oargc; i++) {
  			/*
  			 * The program may have scribbled into its
  			 * argv array, e.g., to remove some arguments.
  			 * If that has happened, break out before
  			 * trying to call strlen on a NULL pointer.
  			 */
  			if (oargv[i] == NULL) {
  				oargc = i;
  				break;
  			}
  			snprintf(obuf + len, SPT_BUFSIZE - len, "%s%s",
  			    len != 0 ? " " : "", oargv[i]);
  			if (len != 0)
  				len++;
  			len += strlen(oargv[i]);
  			if (len >= SPT_BUFSIZE)
  				break;
  		}
  	}
  	ps_strings->ps_nargvstr = nargc;
  	ps_strings->ps_argvstr = nargvp;
  }
  