Commit 0a0cc459 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Tweak continuation-and-comment logic 

I think there was a read-off-the-end-of-the-buffer bug that I fixed.
At least I added some good comments, I hope.
parent 1d29ad89

changes/torrc_continuation

+1 −1
Original line number Diff line number Diff line
@@ -2,5 +2,5 @@ 
    - Support line continuations in torrc.  If a line ends with a

      single backslash character, the newline is ignored, and the

      configuration value is treated as continuing on the next line.

      Implements bug 1929.

      Resolves bug 1929.

src/common/util.c

+42 −4
Original line number Diff line number Diff line
@@ -2284,6 +2284,36 @@ unescape_string(const char *s, char **result, size_t *size_out) 
const char *

parse_config_line_from_str(const char *line, char **key_out, char **value_out)

{

  /* I believe the file format here is supposed to be:

     FILE = (EMPTYLINE | LINE)*



     EMPTYLINE = SPACE* NL | COMMENT NL

     SPACE = ' ' | '\r' | '\t'

     COMMENT = '#' NOT-NL*

     NOT-NL = Any character except '\n'

     NL = '\n'



     LINE = SPACE* KEY SPACE* VALUES NL

     KEY = KEYCHAR+

     KEYCHAR = Any character except ' ', '\r', '\n', '\t', '#', "\"



     VALUES = QUOTEDVALUE | NORMALVALUE

     QUOTEDVALUE = QUOTE QVITEM* QUOTE EOLSPACE?

     QUOTE = '"'

     QVCHAR = KEYCHAR | ESC ('n' | 't' | 'r' | '"' | ESC |'\'' | OCTAL | HEX)

     ESC = "\\"

     OCTAL = ODIGIT (ODIGIT ODIGIT?)?

     HEX = ('x' | 'X') HEXDIGIT HEXDIGIT

     ODIGIT = '0' .. '7'

     HEXDIGIT = '0'..'9' | 'a' .. 'f' | 'A' .. 'F'

     EOLSPACE = SPACE* COMMENT?



     NORMALVALUE = (VALCHAR | ESC ESC_IGNORE | CONTINUATION)* EOLSPACE?

     VALCHAR = Any character except ESC, '#', and '\n'

     ESC_IGNORE = Any character except '#' or '\n'

     CONTINUATION = ESC NL ( COMMENT NL )*

   */



  const char *key, *val, *cp;

  int continuation = 0;
@@ -2323,7 +2353,7 @@ parse_config_line_from_str(const char *line, char **key_out, char **value_out) 
  val = line;



  /* Find the end of the line. */

  if (*line == '\"') { // XXX No continuation here

  if (*line == '\"') { // XXX No continuation handling is done here

    if (!(line = unescape_string(line, value_out, NULL)))

       return NULL;

    while (*line == ' ' || *line == '\t')
@@ -2331,27 +2361,34 @@ parse_config_line_from_str(const char *line, char **key_out, char **value_out) 
    if (*line && *line != '#' && *line != '\n')

      return NULL;

  } else {

    /* Look for the end of the line. */

    while (*line && *line != '\n' && (*line != '#' || continuation)) {

      if (*line == '\\' && line[1] == '\n') {

        continuation = 1;

        ++line;

        line += 2;

      } else if (*line == '#') {

        do {

          ++line;

        } while (*line && *line != '\n');

      }

        if (*line == '\n')

          ++line;

      } else {

        ++line;

      }

    }



    if (*line == '\n') {

      cp = line++;

    } else {

      cp = line;

    }

    /* Now back cp up to be the last nonspace character */

    while (cp>val && TOR_ISSPACE(*(cp-1)))

      --cp;



    tor_assert(cp >= val);



    /* Now copy out and decode the value. */

    *value_out = tor_strndup(val, cp-val);

    if (continuation) {

      char *v_out, *v_in;
@@ -2361,6 +2398,7 @@ parse_config_line_from_str(const char *line, char **key_out, char **value_out) 
          do {

            ++v_in;

          } while (*v_in && *v_in != '\n');

          if (*v_in == '\n')

            ++v_in;

        } else if (v_in[0] == '\\' && v_in[1] == '\n') {

          v_in += 2;