configuration parsing and loading code for rsyncd. This is based

on the Samba config code, so you'll find that the config files will
be eerily familiar if you have ever worked with Samba.

1 files changed, 560 insertions, 0 deletions

diff --git a/params.c b/params.c
new file mode 100644
index 00000000..b89d034c
--- /dev/null
+++ b/params.c
@@ -0,0 +1,560 @@
+/*
+  This modules is based on the params.c module from Samba, written by Karl Auer
+  and much modifed by Christopher Hertel.
+
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * -------------------------------------------------------------------------- **
+ *
+ * Module name: params
+ *
+ * -------------------------------------------------------------------------- **
+ *
+ *  This module performs lexical analysis and initial parsing of a
+ *  Windows-like parameter file.  It recognizes and handles four token
+ *  types:  section-name, parameter-name, parameter-value, and
+ *  end-of-file.  Comments and line continuation are handled
+ *  internally.
+ *
+ *  The entry point to the module is function pm_process().  This
+ *  function opens the source file, calls the Parse() function to parse
+ *  the input, and then closes the file when either the EOF is reached
+ *  or a fatal error is encountered.
+ *
+ *  A sample parameter file might look like this:
+ *
+ *  [section one]
+ *  parameter one = value string
+ *  parameter two = another value
+ *  [section two]
+ *  new parameter = some value or t'other
+ *
+ *  The parameter file is divided into sections by section headers:
+ *  section names enclosed in square brackets (eg. [section one]).
+ *  Each section contains parameter lines, each of which consist of a
+ *  parameter name and value delimited by an equal sign.  Roughly, the
+ *  syntax is:
+ *
+ *    <file>            :==  { <section> } EOF
+ *
+ *    <section>         :==  <section header> { <parameter line> }
+ *
+ *    <section header>  :==  '[' NAME ']'
+ *
+ *    <parameter line>  :==  NAME '=' VALUE '\n'
+ *
+ *  Blank lines and comment lines are ignored.  Comment lines are lines
+ *  beginning with either a semicolon (';') or a pound sign ('#').
+ *
+ *  All whitespace in section names and parameter names is compressed
+ *  to single spaces.  Leading and trailing whitespace is stipped from
+ *  both names and values.
+ *
+ *  Only the first equals sign in a parameter line is significant.
+ *  Parameter values may contain equals signs, square brackets and
+ *  semicolons.  Internal whitespace is retained in parameter values,
+ *  with the exception of the '\r' character, which is stripped for
+ *  historic reasons.  Parameter names may not start with a left square
+ *  bracket, an equal sign, a pound sign, or a semicolon, because these
+ *  are used to identify other tokens.
+ *
+ * -------------------------------------------------------------------------- **
+ */
+
+#include "rsync.h"
+#define BOOL int
+#define False 0
+#define True 1
+#define Realloc realloc
+
+/* -------------------------------------------------------------------------- **
+ * Constants...
+ */
+
+#define BUFR_INC 1024
+
+
+/* -------------------------------------------------------------------------- **
+ * Variables...
+ *
+ *  bufr        - pointer to a global buffer.  This is probably a kludge,
+ *                but it was the nicest kludge I could think of (for now).
+ *  bSize       - The size of the global buffer <bufr>.
+ */
+
+static char *bufr  = NULL;
+static int   bSize = 0;
+
+/* -------------------------------------------------------------------------- **
+ * Functions...
+ */
+
+static int EatWhitespace( FILE *InFile )
+  /* ------------------------------------------------------------------------ **
+   * Scan past whitespace (see ctype(3C)) and return the first non-whitespace
+   * character, or newline, or EOF.
+   *
+   *  Input:  InFile  - Input source.
+   *
+   *  Output: The next non-whitespace character in the input stream.
+   *
+   *  Notes:  Because the config files use a line-oriented grammar, we
+   *          explicitly exclude the newline character from the list of
+   *          whitespace characters.
+   *        - Note that both EOF (-1) and the nul character ('\0') are
+   *          considered end-of-file markers.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  int c;
+
+  for( c = getc( InFile ); isspace( c ) && ('\n' != c); c = getc( InFile ) )
+    ;
+  return( c );
+  } /* EatWhitespace */
+
+static int EatComment( FILE *InFile )
+  /* ------------------------------------------------------------------------ **
+   * Scan to the end of a comment.
+   *
+   *  Input:  InFile  - Input source.
+   *
+   *  Output: The character that marks the end of the comment.  Normally,
+   *          this will be a newline, but it *might* be an EOF.
+   *
+   *  Notes:  Because the config files use a line-oriented grammar, we
+   *          explicitly exclude the newline character from the list of
+   *          whitespace characters.
+   *        - Note that both EOF (-1) and the nul character ('\0') are
+   *          considered end-of-file markers.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  int c;
+
+  for( c = getc( InFile ); ('\n'!=c) && (EOF!=c) && (c>0); c = getc( InFile ) )
+    ;
+  return( c );
+  } /* EatComment */
+
+static int Continuation( char *line, int pos )
+  /* ------------------------------------------------------------------------ **
+   * Scan backards within a string to discover if the last non-whitespace
+   * character is a line-continuation character ('\\').
+   *
+   *  Input:  line  - A pointer to a buffer containing the string to be
+   *                  scanned.
+   *          pos   - This is taken to be the offset of the end of the
+   *                  string.  This position is *not* scanned.
+   *
+   *  Output: The offset of the '\\' character if it was found, or -1 to
+   *          indicate that it was not.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  pos--;
+  while( (pos >= 0) && isspace(line[pos]) )
+     pos--;
+
+  return( ((pos >= 0) && ('\\' == line[pos])) ? pos : -1 );
+  } /* Continuation */
+
+
+static BOOL Section( FILE *InFile, BOOL (*sfunc)(char *) )
+  /* ------------------------------------------------------------------------ **
+   * Scan a section name, and pass the name to function sfunc().
+   *
+   *  Input:  InFile  - Input source.
+   *          sfunc   - Pointer to the function to be called if the section
+   *                    name is successfully read.
+   *
+   *  Output: True if the section name was read and True was returned from
+   *          <sfunc>.  False if <sfunc> failed or if a lexical error was
+   *          encountered.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  int   c;
+  int   i;
+  int   end;
+  char *func  = "params.c:Section() -";
+
+  i = 0;      /* <i> is the offset of the next free byte in bufr[] and  */
+  end = 0;    /* <end> is the current "end of string" offset.  In most  */
+              /* cases these will be the same, but if the last          */
+              /* character written to bufr[] is a space, then <end>     */
+              /* will be one less than <i>.                             */
+
+  c = EatWhitespace( InFile );    /* We've already got the '['.  Scan */
+                                  /* past initial white space.        */
+
+  while( (EOF != c) && (c > 0) )
+    {
+
+    /* Check that the buffer is big enough for the next character. */
+    if( i > (bSize - 2) )
+      {
+      bSize += BUFR_INC;
+      bufr   = Realloc( bufr, bSize );
+      if( NULL == bufr )
+        {
+        rprintf(FERROR, "%s Memory re-allocation failure.", func);
+        return( False );
+        }
+      }
+
+    /* Handle a single character. */
+    switch( c )
+      {
+      case ']':                       /* Found the closing bracket.         */
+        bufr[end] = '\0';
+        if( 0 == end )                  /* Don't allow an empty name.       */
+          {
+          rprintf(FERROR, "%s Empty section name in configuration file.\n", func );
+          return( False );
+          }
+        if( !sfunc( bufr ) )            /* Got a valid name.  Deal with it. */
+          return( False );
+        (void)EatComment( InFile );     /* Finish off the line.             */
+        return( True );
+
+      case '\n':                      /* Got newline before closing ']'.    */
+        i = Continuation( bufr, i );    /* Check for line continuation.     */
+        if( i < 0 )
+          {
+          bufr[end] = '\0';
+          rprintf(FERROR, "%s Badly formed line in configuration file: %s\n",
+                   func, bufr );
+          return( False );
+          }
+        end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
+        c = getc( InFile );             /* Continue with next line.         */
+        break;
+
+      default:                        /* All else are a valid name chars.   */
+        if( isspace( c ) )              /* One space per whitespace region. */
+          {
+          bufr[end] = ' ';
+          i = end + 1;
+          c = EatWhitespace( InFile );
+          }
+        else                            /* All others copy verbatim.        */
+          {
+          bufr[i++] = c;
+          end = i;
+          c = getc( InFile );
+          }
+      }
+    }
+
+  /* We arrive here if we've met the EOF before the closing bracket. */
+  rprintf(FERROR, "%s Unexpected EOF in the configuration file: %s\n", func, bufr );
+  return( False );
+  } /* Section */
+
+static BOOL Parameter( FILE *InFile, BOOL (*pfunc)(char *, char *), int c )
+  /* ------------------------------------------------------------------------ **
+   * Scan a parameter name and value, and pass these two fields to pfunc().
+   *
+   *  Input:  InFile  - The input source.
+   *          pfunc   - A pointer to the function that will be called to
+   *                    process the parameter, once it has been scanned.
+   *          c       - The first character of the parameter name, which
+   *                    would have been read by Parse().  Unlike a comment
+   *                    line or a section header, there is no lead-in
+   *                    character that can be discarded.
+   *
+   *  Output: True if the parameter name and value were scanned and processed
+   *          successfully, else False.
+   *
+   *  Notes:  This function is in two parts.  The first loop scans the
+   *          parameter name.  Internal whitespace is compressed, and an
+   *          equal sign (=) terminates the token.  Leading and trailing
+   *          whitespace is discarded.  The second loop scans the parameter
+   *          value.  When both have been successfully identified, they are
+   *          passed to pfunc() for processing.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  int   i       = 0;    /* Position within bufr. */
+  int   end     = 0;    /* bufr[end] is current end-of-string. */
+  int   vstart  = 0;    /* Starting position of the parameter value. */
+  char *func    = "params.c:Parameter() -";
+
+  /* Read the parameter name. */
+  while( 0 == vstart )  /* Loop until we've found the start of the value. */
+    {
+
+    if( i > (bSize - 2) )       /* Ensure there's space for next char.    */
+      {
+      bSize += BUFR_INC;
+      bufr   = Realloc( bufr, bSize );
+      if( NULL == bufr )
+        {
+        rprintf(FERROR, "%s Memory re-allocation failure.", func) ;
+        return( False );
+        }
+      }
+
+    switch( c )
+      {
+      case '=':                 /* Equal sign marks end of param name. */
+        if( 0 == end )              /* Don't allow an empty name.      */
+          {
+          rprintf(FERROR, "%s Invalid parameter name in config. file.\n", func );
+          return( False );
+          }
+        bufr[end++] = '\0';         /* Mark end of string & advance.   */
+        i       = end;              /* New string starts here.         */
+        vstart  = end;              /* New string is parameter value.  */
+        bufr[i] = '\0';             /* New string is nul, for now.     */
+        break;
+
+      case '\n':                /* Find continuation char, else error. */
+        i = Continuation( bufr, i );
+        if( i < 0 )
+          {
+          bufr[end] = '\0';
+          rprintf(FERROR, "%s Ignoring badly formed line in configuration file: %s\n",
+                   func, bufr );
+          return( True );
+          }
+        end = ( (i > 0) && (' ' == bufr[i - 1]) ) ? (i - 1) : (i);
+        c = getc( InFile );       /* Read past eoln.                   */
+        break;
+
+      case '\0':                /* Shouldn't have EOF within param name. */
+      case EOF:
+        bufr[i] = '\0';
+        rprintf(FERROR, "%s Unexpected end-of-file at: %s\n", func, bufr );
+        return( True );
+
+      default:
+        if( isspace( c ) )     /* One ' ' per whitespace region.       */
+          {
+          bufr[end] = ' ';
+          i = end + 1;
+          c = EatWhitespace( InFile );
+          }
+        else                   /* All others verbatim.                 */
+          {
+          bufr[i++] = c;
+          end = i;
+          c = getc( InFile );
+          }
+      }
+    }
+
+  /* Now parse the value. */
+  c = EatWhitespace( InFile );  /* Again, trim leading whitespace. */
+  while( (EOF !=c) && (c > 0) )
+    {
+
+    if( i > (bSize - 2) )       /* Make sure there's enough room. */
+      {
+      bSize += BUFR_INC;
+      bufr   = Realloc( bufr, bSize );
+      if( NULL == bufr )
+        {
+        rprintf(FERROR, "%s Memory re-allocation failure.", func) ;
+        return( False );
+        }
+      }
+
+    switch( c )
+      {
+      case '\r':              /* Explicitly remove '\r' because the older */
+        c = getc( InFile );   /* version called fgets_slash() which also  */
+        break;                /* removes them.                            */
+
+      case '\n':              /* Marks end of value unless there's a '\'. */
+        i = Continuation( bufr, i );
+        if( i < 0 )
+          c = 0;
+        else
+          {
+          for( end = i; (end >= 0) && isspace(bufr[end]); end-- )
+            ;
+          c = getc( InFile );
+          }
+        break;
+
+      default:               /* All others verbatim.  Note that spaces do */
+        bufr[i++] = c;       /* not advance <end>.  This allows trimming  */
+        if( !isspace( c ) )  /* of whitespace at the end of the line.     */
+          end = i;
+        c = getc( InFile );
+        break;
+      }
+    }
+  bufr[end] = '\0';          /* End of value. */
+
+  return( pfunc( bufr, &bufr[vstart] ) );   /* Pass name & value to pfunc().  */
+  } /* Parameter */
+
+static BOOL Parse( FILE *InFile,
+                   BOOL (*sfunc)(char *),
+                   BOOL (*pfunc)(char *, char *) )
+  /* ------------------------------------------------------------------------ **
+   * Scan & parse the input.
+   *
+   *  Input:  InFile  - Input source.
+   *          sfunc   - Function to be called when a section name is scanned.
+   *                    See Section().
+   *          pfunc   - Function to be called when a parameter is scanned.
+   *                    See Parameter().
+   *
+   *  Output: True if the file was successfully scanned, else False.
+   *
+   *  Notes:  The input can be viewed in terms of 'lines'.  There are four
+   *          types of lines:
+   *            Blank      - May contain whitespace, otherwise empty.
+   *            Comment    - First non-whitespace character is a ';' or '#'.
+   *                         The remainder of the line is ignored.
+   *            Section    - First non-whitespace character is a '['.
+   *            Parameter  - The default case.
+   * 
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  int    c;
+
+  c = EatWhitespace( InFile );
+  while( (EOF != c) && (c > 0) )
+    {
+    switch( c )
+      {
+      case '\n':                        /* Blank line. */
+        c = EatWhitespace( InFile );
+        break;
+
+      case ';':                         /* Comment line. */
+      case '#':
+        c = EatComment( InFile );
+        break;
+
+      case '[':                         /* Section Header. */
+        if( !Section( InFile, sfunc ) )
+          return( False );
+        c = EatWhitespace( InFile );
+        break;
+
+      case '\\':                        /* Bogus backslash. */
+        c = EatWhitespace( InFile );
+        break;
+
+      default:                          /* Parameter line. */
+        if( !Parameter( InFile, pfunc, c ) )
+          return( False );
+        c = EatWhitespace( InFile );
+        break;
+      }
+    }
+  return( True );
+  } /* Parse */
+
+static FILE *OpenConfFile( char *FileName )
+  /* ------------------------------------------------------------------------ **
+   * Open a configuration file.
+   *
+   *  Input:  FileName  - The pathname of the config file to be opened.
+   *
+   *  Output: A pointer of type (FILE *) to the opened file, or NULL if the
+   *          file could not be opened.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  FILE *OpenedFile;
+  char *func = "params.c:OpenConfFile() -";
+
+  if( NULL == FileName || 0 == *FileName )
+    {
+    rprintf(FERROR,"%s No configuration filename specified.\n", func);
+    return( NULL );
+    }
+
+  OpenedFile = fopen( FileName, "r" );
+  if( NULL == OpenedFile )
+    {
+    rprintf(FERROR,"%s Unable to open configuration file \"%s\":\n\t%s\n",
+	    func, FileName, strerror(errno));
+    }
+
+  return( OpenedFile );
+  } /* OpenConfFile */
+
+BOOL pm_process( char *FileName,
+                 BOOL (*sfunc)(char *),
+                 BOOL (*pfunc)(char *, char *) )
+  /* ------------------------------------------------------------------------ **
+   * Process the named parameter file.
+   *
+   *  Input:  FileName  - The pathname of the parameter file to be opened.
+   *          sfunc     - A pointer to a function that will be called when
+   *                      a section name is discovered.
+   *          pfunc     - A pointer to a function that will be called when
+   *                      a parameter name and value are discovered.
+   *
+   *  Output: TRUE if the file was successfully parsed, else FALSE.
+   *
+   * ------------------------------------------------------------------------ **
+   */
+  {
+  int   result;
+  FILE *InFile;
+  char *func = "params.c:pm_process() -";
+
+  InFile = OpenConfFile( FileName );          /* Open the config file. */
+  if( NULL == InFile )
+    return( False );
+
+  if( NULL != bufr )                          /* If we already have a buffer */
+    result = Parse( InFile, sfunc, pfunc );   /* (recursive call), then just */
+                                              /* use it.                     */
+
+  else                                        /* If we don't have a buffer   */
+    {                                         /* allocate one, then parse,   */
+    bSize = BUFR_INC;                         /* then free.                  */
+    bufr = (char *)malloc( bSize );
+    if( NULL == bufr )
+      {
+      rprintf(FERROR,"%s memory allocation failure.\n", func);
+      fclose(InFile);
+      return( False );
+      }
+    result = Parse( InFile, sfunc, pfunc );
+    free( bufr );
+    bufr  = NULL;
+    bSize = 0;
+    }
+
+  fclose(InFile);
+
+  if( !result )                               /* Generic failure. */
+    {
+    rprintf(FERROR,"%s Failed.  Error returned from params.c:parse().\n", func);
+    return( False );
+    }
+
+  return( True );                             /* Generic success. */
+  } /* pm_process */
+
+/* -------------------------------------------------------------------------- */