parser.c

linux下获取一些环境信息的代码

      return NULL; /* can't have any more options */
#if 0
    case 'r':
      trace("-r some Digital Unix thing about warnings...\n");
      trace("   or SCO's option to chroot() for new /proc and /dev.\n");
      return "The -r option is reserved.";
      break;
#endif
    case 's': /* end */
      trace("-s Select processes belonging to the sessions given.\n");
      arg=get_opt_arg();
      if(!arg) return "List of session IDs must follow -s.";
      err=parse_list(arg, parse_pid);
      if(err) return err;
      selection_list->typecode = SEL_SESS;
      return NULL; /* can't have any more options */
    case 't': /* end */
      trace("-t select by tty.\n");
      arg=get_opt_arg();
      if(!arg) return "List of terminals (pty, tty...) must follow -t.";
      err=parse_list(arg, parse_tty);
      if(err) return err;
      selection_list->typecode = SEL_TTY;
      return NULL; /* can't have any more options */
    case 'u': /* end */
      trace("-u select by user ID (the EUID?) (supports names).\n");
      arg=get_opt_arg();
      if(!arg) return "List of users must follow -u.";
      err=parse_list(arg, parse_uid);
      if(err) return err;
      selection_list->typecode = SEL_EUID;
      return NULL; /* can't have any more options */
    case 'w':
      trace("-w wide output.\n");
      w_count++;
      break;
    case 'x':  /* behind personality until "ps -ax" habit is uncommon */
      if(personality & PER_SVR4_x){
        // Same as -y, but for System V Release 4 MP
        trace("-x works like Sun Solaris & SCO Unixware -y option\n");
        format_modifiers |= FM_y;
        break;
      }
      if(personality & PER_HPUX_x){
        trace("-x extends the command line\n");
        w_count += 2;
        unix_f_option = 1;
        break;
      }
      return "Must set personality to get -x option.";
    case 'y':  /* Sun's -l hack (also: Irix "lnode" resource control info) */
      trace("-y Print lnone info in UID/USER column or do Sun -l hack.\n");
      format_modifiers |= FM_y;
      break;
#if 0
    // This must be verified against SVR4-MP (UnixWare or Powermax)
    case 'z':     /* alias of Mandatory Access Control level info */
      trace("-z shows aliased MAC info\n");
      format_modifiers |= FM_M;
      break;
    // Solaris 10 does this
    case 'z':     /* select by zone */
      trace("-z secects by zone\n");
      arg=get_opt_arg();
      if(!arg) return "List of zones (contexts, labels, whatever?) must follow -z.";
      err=parse_list(arg, parse_zone);
      if(err) return err;
      selection_list->typecode = SEL_ZONE;
      return NULL; /* can't have any more options */
#endif
    case '-':
      return "Embedded '-' among SysV options makes no sense.";
      break;
    case '\0':
      return "Please report the \"SysV \\0 can't happen\" bug.";
      break;
    default:
      return "Unsupported SysV option.";
    } /* switch */
  } /* while */
  return NULL;
}

/************************* parse BSD options **********************/
static const char *parse_bsd_option(void){
  const char *arg;
  const char *err;

  flagptr = ps_argv[thisarg];  /* assume we _have_ a '-' */
  if(flagptr[0]=='-'){
    if(!force_bsd) return "Can't happen!  Problem #1.";
  }else{
    flagptr--; /* off beginning, will increment before use */
    if(personality & PER_FORCE_BSD){
      if(!force_bsd) return "Can't happen!  Problem #2.";
    }else{
      if(force_bsd) return "2nd chance parse failed, not BSD or SysV.";
    }
  }

  while(*++flagptr){
    switch(*flagptr){
    case '0' ... '9': /* end */
      trace("0..9  Old BSD-style select by process ID\n");
      arg=flagptr;
      err=parse_list(arg, parse_pid);
      if(err) return err;
      selection_list->typecode = SEL_PID;
      return NULL; /* can't have any more options */
#if 0
    case 'A':
      /* maybe this just does a larger malloc() ? */
      trace("A Increases the argument space (Digital Unix)\n");
      return "Option A is reserved.";
      break;
    case 'C':
      /* should divide result by 1-(e**(foo*log(bar))) */
      trace("C Use raw CPU time for %%CPU instead of decaying ave\n");
      return "Option C is reserved.";
      break;
#endif
    case 'H':    // The FreeBSD way (NetBSD:s OpenBSD:k FreeBSD:H  -- NIH???)
      trace("H Print LWP (thread) info.\n");   // was: Use /vmcore as c-dumpfile\n");
      thread_flags |= TF_B_H;
      //format_modifiers |= FM_L;    // FIXME: determine if we need something like this
      break;
    case 'L': /* single */
      trace("L List all format specifiers\n");
      exclusive("L");
      print_format_specifiers();
      exit(0);
    case 'M':   // undocumented for now: these are proliferating!
      trace("M MacOS X thread display, like AIX/Tru64\n");
      thread_flags |= TF_B_m;
      break;
    case 'N': /* end */
      trace("N Specify namelist file\n");
      arg=get_opt_arg();
      if(!arg) return "Alternate System.map file must follow N.";
      namelist_file = arg;
      return NULL; /* can't have any more options */
    case 'O': /* end */
      trace("O Like o + defaults, add new columns after PID. Also sort.\n");
      arg=get_opt_arg();
      if(!arg) return "Format or sort specification must follow O.";
      defer_sf_option(arg, SF_B_O);
      return NULL; /* can't have any more options */
      break;
    case 'S':
      trace("S include dead kids in sum\n");
      include_dead_children = 1;
      break;
    case 'T':
      trace("T Select all processes on this terminal\n");
      /* put our tty on a tiny list */
      {
        selection_node *node;
        node = malloc(sizeof(selection_node));
        node->u = malloc(sizeof(sel_union));
        node->u[0].tty = cached_tty;
        node->typecode = SEL_TTY;
        node->n = 1;
        node->next = selection_list;
        selection_list = node;
      }
      break;
    case 'U': /* end */
      trace("U Select processes for specified users.\n");
      arg=get_opt_arg();
      if(!arg) return "List of users must follow U.";
      err=parse_list(arg, parse_uid);
      if(err) return err;
      selection_list->typecode = SEL_EUID;
      return NULL; /* can't have any more options */
    case 'V': /* single */
      trace("V show version info\n");
      exclusive("V");
      display_version();
      exit(0);
    case 'W':
      trace("W N/A get swap info from ... not /dev/drum.\n");
      return "Obsolete W option not supported. (You have a /dev/drum?)";
      break;
    case 'X':
      trace("X Old Linux i386 register format\n");
      format_flags |= FF_LX;
      break;
    case 'Z':  /* FreeBSD does MAC like SGI's Irix does it */
      trace("Z Print security label for Mandatory Access Control.\n");
      format_modifiers |= FM_M;
      break;
    case 'a':
      trace("a Select all w/tty, including other users\n");
      simple_select |= SS_B_a;
      break;
    case 'c':
      trace("c true command name\n");
      bsd_c_option = 1;
      break;
    case 'e':
      trace("e environment\n");
      bsd_e_option = 1;
      break;
    case 'f':
      trace("f ASCII art forest\n");
      forest_type = 'b';
      break;
    case 'g':
      trace("g _all_, even group leaders!.\n");
      simple_select |= SS_B_g;
      break;
    case 'h':
      trace("h Repeat header... yow.\n");
      if(header_type) return "Only one heading option may be specified.";
      if(personality & PER_BSD_h) header_type = HEAD_MULTI;
      else                        header_type = HEAD_NONE;
      break;
    case 'j':
      trace("j job control format\n");
      format_flags |= FF_Bj;
      break;
    case 'k':
      // OpenBSD: don't hide "kernel threads" -- like the swapper?
      // trace("k Print LWP (thread) info.\n");   // was: Use /vmcore as c-dumpfile\n");

      // NetBSD, and soon (?) FreeBSD: sort-by-keyword
      trace("k Specify sorting keywords.\n");
      arg=get_opt_arg();
      if(!arg) return "Long sort specification must follow 'k'.";
      defer_sf_option(arg, SF_G_sort);
      return NULL; /* can't have any more options */
    case 'l':
      trace("l Display long format\n");
      format_flags |= FF_Bl;
      break;
    case 'm':
      trace("m all threads, sort on mem use, show mem info\n");
      if(personality & PER_OLD_m){
        format_flags |= FF_Lm;
        break;
      }
      if(personality & PER_BSD_m){
        defer_sf_option("pmem", SF_B_m);
        break;
      }
      thread_flags |= TF_B_m;
      break;
    case 'n':
      trace("n Numeric output for WCHAN, and USER replaced by UID\n");
      wchan_is_number = 1;
      user_is_number = 1;
      /* TODO add tty_is_number too? */
      break;
    case 'o': /* end */
      trace("o Specify user-defined format\n");
      arg=get_opt_arg();
      if(!arg) return "Format specification must follow o.";
      defer_sf_option(arg, SF_B_o);
      return NULL; /* can't have any more options */
    case 'p': /* end */
      trace("p Select by process ID\n");
      arg=get_opt_arg();
      if(!arg) return "List of process IDs must follow p.";
      err=parse_list(arg, parse_pid);
      if(err) return err;
      selection_list->typecode = SEL_PID;
      return NULL; /* can't have any more options */
    case 'r':
      trace("r Select running processes\n");
      running_only = 1;
      break;
    case 's':
      trace("s Display signal format\n");
      format_flags |= FF_Bs;
      break;
    case 't': /* end */
      trace("t Select by tty.\n");
      /* List of terminals (tty, pty...) _should_ follow t. */
      arg=get_opt_arg();
      if(!arg){
        /* Wow, obsolete BSD syntax. Put our tty on a tiny list. */
        selection_node *node;
        node = malloc(sizeof(selection_node));
        node->u = malloc(sizeof(sel_union));
        node->u[0].tty = cached_tty;
        node->typecode = SEL_TTY;
        node->n = 1;
        node->next = selection_list;
        selection_list = node;
        return NULL;
      }
      err=parse_list(arg, parse_tty);
      if(err) return err;
      selection_list->typecode = SEL_TTY;
      return NULL; /* can't have any more options */
    case 'u':
      trace("u Display user-oriented\n");
      format_flags |= FF_Bu;
      break;
    case 'v':
      trace("v Display virtual memory\n");
      format_flags |= FF_Bv;
      break;
    case 'w':
      trace("w wide output\n");
      w_count++;
      break;
    case 'x':
      trace("x Select processes without controlling ttys\n");
      simple_select |= SS_B_x;
      break;
#if 0
    case 'y':
      // DragonFlyBSD iac (interactivity measure) format
      // uid,pid,ppid,cpu,pri,iac,nice,wchan,state,tt,time,command
      // (they use 'Y' to sort by this "iac" thing; 'y' implies 'Y')
      // Range is -127 .. 127, with lower numbers being more
      // interactive and higher numbers more batch-like.
      trace("y Display interactivity measure\n");
      format_flags |= FF_Bv;
      break;
#endif
    case '-':
      return "Embedded '-' among BSD options makes no sense.";
      break;
    case '\0':
      return "Please report the \"BSD \\0 can't happen\" bug.";
      break;
    default:
      return "Unsupported option (BSD syntax)";
    } /* switch */
  } /* while */
  return NULL;
}

/*************** gnu long options **********************/

/*
 * Return the argument or NULL
 */
static const char *grab_gnu_arg(void){
  switch(*flagptr){     /* argument is part of ps_argv[thisarg] */
  default:
    return NULL;                     /* something bad */
  case '=': case ':':
    if(*++flagptr) return flagptr;   /* found it */
    return NULL;                     /* empty '=' or ':' */
  case '\0': /* try next argv[] */
    ;
  }
  if(thisarg+2 > ps_argc) return NULL;   /* there is nothing left */
  /* argument follows ps_argv[thisarg] */
  if(*(ps_argv[thisarg+1]) == '\0') return NULL;
  return ps_argv[++thisarg];
}

typedef struct gnu_table_struct {
  const char *name; /* long option name */
  const void *jump; /* See gcc extension info.   :-)   */
} gnu_table_struct;

static int compare_gnu_table_structs(const void *a, const void *b){
  return strcmp(((const gnu_table_struct*)a)->name,((const gnu_table_struct*)b)->name);
}

/* Option arguments are after ':', after '=', or in argv[n+1] */
static const char *parse_gnu_option(void){
  const char *arg;
  const char *err;
  char *s;
  size_t sl;
  char buf[16];
  gnu_table_struct findme = { buf, NULL};
  gnu_table_struct *found;
  static const gnu_table_struct gnu_table[] = {
  {"Group",         &&case_Group},       /* rgid */
  {"User",          &&case_User},        /* ruid */
  {"cols",          &&case_cols},
  {"columns",       &&case_columns},
  {"context",       &&case_context},
  {"cumulative",    &&case_cumulative},
  {"deselect",      &&case_deselect},    /* -N */
  {"forest",        &&case_forest},      /* f -H */
  {"format",        &&case_format},
  {"group",         &&case_group},       /* egid */
  {"header",        &&case_header},
  {"headers",       &&case_headers},
  {"heading",       &&case_heading},
  {"headings",      &&case_headings},
  {"help",          &&case_help},
  {"info",          &&case_info},
  {"lines",         &&case_lines},
  {"no-header",     &&case_no_header},
  {"no-headers",    &&case_no_headers},
  {"no-heading",    &&case_no_heading},
  {"no-headings",   &&case_no_headings},
  {"noheader",      &&case_noheader},
  {"noheaders",     &&case_noheaders},
  {"noheading",     &&case_noheading},
  {"noheadings",    &&case_noheadings},
  {"pid",           &&case_pid},
  {"ppid",          &&case_ppid},
  {"rows",          &&case_rows},
  {"sid",           &&case_sid},
  {"sort",          &&case_sort},
  {"tty",           &&case_tty},
  {"user",          &&case_user},        /* euid */
  {"version",       &&case_version},
  {"width",         &&case_width},
  };
  const int gnu_table_count = sizeof(gnu_table)/sizeof(gnu_table_struct);

  s = ps_argv[thisarg]+2;
  sl = strcspn(s,":=");
  if(sl > 15) return "Unknown gnu long option.";
  strncpy(buf, s, sl);
  buf[sl] = '\0';
  flagptr = s+sl;

  found = bsearch(&findme, gnu_table, gnu_table_count,