escape.c

linux下获取一些环境信息的代码

/*
 * Copyright 1998-2002 by Albert Cahalan; all rights resered.         
 * This file may be used subject to the terms and conditions of the
 * GNU Library General Public License Version 2, or any later version  
 * at your option, as published by the Free Software Foundation.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Library General Public License for more details.
 */                                 
#include <stdio.h>
#include <sys/types.h>
#include <string.h>
#include "procps.h"
#include "escape.h"
#include "readproc.h"

#if (__GNU_LIBRARY__ >= 6)
# include <wchar.h>
# include <wctype.h>
# include <stdlib.h>  /* MB_CUR_MAX */
# include <ctype.h>
# include <langinfo.h>
#endif

#if (__GNU_LIBRARY__ >= 6)
static int escape_str_utf8(char *restrict dst, const char *restrict src, int bufsize, int *maxcells){
  int my_cells = 0;
  int my_bytes = 0;
  mbstate_t s;
  
  memset(&s, 0, sizeof (s));
  
  for(;;) {
    wchar_t wc;
    int len = 0;
	  
    if(my_cells >= *maxcells || my_bytes+1 >= bufsize) 
      break;
    
    if (!(len = mbrtowc (&wc, src, MB_CUR_MAX, &s)))
      /* 'str' contains \0 */
      break;
    
    if (len < 0) {
      /* invalid multibyte sequence -- zeroize state */
      memset (&s, 0, sizeof (s));
      *(dst++) = '?';
      src++;
      my_cells++; 
      my_bytes++;

    } else if (len==1) {
      /* non-multibyte */
      *(dst++) = isprint(*src) ? *src : '?';
      src++;
      my_cells++;
      my_bytes++;
      
    } else if (!iswprint(wc)) {
      /* multibyte - no printable */
      *(dst++) = '?';
      src+=len;
      my_cells++;
      my_bytes++; 
    
    } else {
      /* multibyte - printable */	
      int wlen = wcwidth(wc);

      if (wlen==0) {
	// invisible multibyte -- we don't ignore it, because some terminal 
	// interpret it wrong and more safe is replace it with '?'
	*(dst++) = '?';
	src+=len;
	my_cells++;
	my_bytes++;
      } else {
        // multibyte - printable
        // Got space?
        if (my_cells+wlen > *maxcells || my_bytes+1+len >= bufsize) break;
        // 0x9b is control byte for some terminals
        if (memchr(src, 0x9B, len)) {
	  // unsafe multibyte
	  *(dst++) = '?';
	  src+=len;
	  my_cells++;
	  my_bytes++;
        } else {
	  // safe multibyte
       	  memcpy(dst, src, len);
	  my_cells += wlen;
	  dst += len;
	  my_bytes += len;
          src += len;
        }
      }
    }
    //fprintf(stdout, "cells: %d\n", my_cells);
  }
  *(dst++) = '\0';

  // fprintf(stderr, "maxcells: %d, my_cells; %d\n", *maxcells, my_cells);
  
  *maxcells -= my_cells;
  return my_bytes;        // bytes of text, excluding the NUL
}

#endif /* __GNU_LIBRARY__  */

/* sanitize a string via one-way mangle */
int escape_str(char *restrict dst, const char *restrict src, int bufsize, int *maxcells){
  unsigned char c;
  int my_cells = 0;
  int my_bytes = 0;
  const char codes[] =
  "Z-------------------------------"
  "********************************"
  "********************************"
  "*******************************-"
  "--------------------------------"
  "********************************"
  "********************************"
  "********************************";
  
#if (__GNU_LIBRARY__ >= 6)
  static int utf_init=0;
  
  if(utf_init==0){
     /* first call -- check if UTF stuff is usable */
     char *enc = nl_langinfo(CODESET);
     utf_init = enc && strcasecmp(enc, "UTF-8")==0 ? 1 : -1;
  }
  if (utf_init==1)
     /* UTF8 locales */
     return escape_str_utf8(dst, src, bufsize, maxcells);
#endif
		  
  if(bufsize > *maxcells+1) bufsize=*maxcells+1; // FIXME: assumes 8-bit locale

  for(;;){
    if(my_cells >= *maxcells || my_bytes+1 >= bufsize) 
      break;
    c = (unsigned char) *(src++);
    if(!c) break;
    if(codes[c]=='-') c='?';
    my_cells++;
    my_bytes++;
    *(dst++) = c;
  }
  *(dst++) = '\0';
  
  *maxcells -= my_cells;
  return my_bytes;        // bytes of text, excluding the NUL
}

/////////////////////////////////////////////////

// escape an argv or environment string array
//
// bytes arg means sizeof(buf)
int escape_strlist(char *restrict dst, const char *restrict const *restrict src, size_t bytes, int *cells){
  size_t i = 0;

  for(;;){
    i += escape_str(dst+i, *src, bytes-i, cells);
    if(bytes-i < 3) break;  // need room for space, a character, and the NUL
    src++;
    if(!*src) break;  // need something to print
    if (*cells<=1) break;  // need room for printed size of text
    dst[i++] = ' ';
    --*cells;
  }
  return i;    // bytes, excluding the NUL
}

///////////////////////////////////////////////////

int escape_command(char *restrict const outbuf, const proc_t *restrict const pp, int bytes, int *cells, unsigned flags){
  int overhead = 0;
  int end = 0;

  if(flags & ESC_ARGS){
    const char **lc = (const char**)pp->cmdline;
    if(lc && *lc) return escape_strlist(outbuf, lc, bytes, cells);
  }
  if(flags & ESC_BRACKETS){
    overhead += 2;
  }
  if(flags & ESC_DEFUNCT){
    if(pp->state=='Z') overhead += 10;    // chars in " <defunct>"
    else flags &= ~ESC_DEFUNCT;
  }
  if(overhead + 1 >= *cells){  // if no room for even one byte of the command name
    // you'd damn well better have _some_ space
//    outbuf[0] = '-';  // Oct23
    outbuf[1] = '\0';
    return 1;
  }
  if(flags & ESC_BRACKETS){
    outbuf[end++] = '[';
  }
  *cells -= overhead;
  end += escape_str(outbuf+end, pp->cmd, bytes-overhead, cells);

  // Hmmm, do we want "[foo] <defunct>" or "[foo <defunct>]"?
  if(flags & ESC_BRACKETS){
    outbuf[end++] = ']';
  }
  if(flags & ESC_DEFUNCT){
    memcpy(outbuf+end, " <defunct>", 10);
    end += 10;
  }
  outbuf[end] = '\0';
  return end;  // bytes, not including the NUL
}