Re: Syslog Facility Patch - Mailing list pgsql-hackers

* Peter Eisentraut <peter_e@gmx.net> [001115 10:26]:
> Larry Rosenman writes:
> 
> > Ok, so what I think(?) needs to happen is the FIXME: tag needs to be
> > handled.  We need to code a version of src/backend/parser/scansup.c
> > that doesn't use palloc, and also strips the apostrophes from the
> > front and end of the string?  This doesn't look that hard. Do I have 
> > "permission" to play with it, and submit a patch when I've got it
> > fixed? 
> 
> Some background information:  The current
> 
>   name = value
> 
> syntax is lexically compatible with the syntax of the SET command.  
> Therefore you can't have "funny" characters in 'value' unless
> single-quoted.
I added period(.), hyphen(-), and underscore(_).
> 
> Now in the context of the config file this seems overly restrictive.  
> Therefore I'd agree that we relax that a bit and allow more characters to
> go into 'value' unquoted.  I'm not quite sure which, but to prevent
> confusion I'd prefer no semicolons, whitespace, or equal signs, possibly
> others.
> 
> This would require making 'value' a different token type from 'name',
> because the latter should not accept these characters.
done, as GUC_UNQUOTED_STRING.
> 
> Additionally, the FIXME ought to be done.  I'd prefer it if it accepted
> the exact same escapes and all as does the SQL parser/scanner.  So it
> ought to be a copy and paste from scansup.c.  I'm not excited about
> allowing double-quotes though.
Done.  Added as GUC_scanstr. 

Here is a patch.  Comments? 

Index: src/backend/utils/misc/guc-file.l
===================================================================
RCS file: /home/projects/pgsql/cvsroot/pgsql/src/backend/utils/misc/guc-file.l,v
retrieving revision 1.4
diff -c -r1.4 guc-file.l
*** src/backend/utils/misc/guc-file.l    2000/07/27 19:49:18    1.4
--- src/backend/utils/misc/guc-file.l    2000/11/15 18:13:20
***************
*** 16,21 ****
--- 16,22 ---- #include <sys/stat.h> #include <unistd.h> #include <errno.h>
+ #include <ctype.h>  #include "miscadmin.h" #include "storage/fd.h"
***************
*** 32,37 ****
--- 33,39 ----     GUC_INTEGER = 3,     GUC_REAL = 4,     GUC_EQUALS = 5,
+     GUC_UNQUOTED_STRING = 6,     GUC_EOL = 99,     GUC_ERROR = 100 };
***************
*** 45,51 ****  /* prototype, so compiler is happy with our high warnings setting */ int GUC_yylex(void);
!  %}  SIGN            ("-"|"+")
--- 47,53 ----  /* prototype, so compiler is happy with our high warnings setting */ int GUC_yylex(void);
! char *GUC_scanstr(char *); %}  SIGN            ("-"|"+")
***************
*** 69,76 ****  * work right. Now there are no string options, and if there were then  * the unquoted (`ID') tokens
shouldstill work. Of course this only  * affects the configuration file.  */
 
! STRING          \'([^'\n]|\\.)*'  %% 
--- 71,83 ----  * work right. Now there are no string options, and if there were then  * the unquoted (`ID') tokens
shouldstill work. Of course this only  * affects the configuration file.
 
+  * LER 14NOV2000: I set it up to accept either a quoted string or a string
+  * in apostrophes.  I then kill off the 1st and last characters.  There is 
+  * no special handling for doubled terminators or 'C' escapes. 
+  * this allows most other characters to be used.  */
! UNQUOTED_STRING {LETTER}({LETTER_OR_DIGIT}|[-._])*
! STRING          (\'|\")([^'"\n]|\\.)*(\'|\")  %% 
***************
*** 80,85 ****
--- 87,93 ----  {ID}            return GUC_ID; {STRING}        return GUC_STRING;
+ {UNQUOTED_STRING} return GUC_UNQUOTED_STRING; {INTEGER}       return GUC_INTEGER; {REAL}          return GUC_REAL; =
            return GUC_EQUALS;
 
***************
*** 210,220 ****                 if (token == GUC_EQUALS)                     token = yylex(); 
!                 if (token != GUC_ID && token != GUC_STRING && token != GUC_INTEGER && token != GUC_REAL)
      goto parse_error;                 opt_value = strdup(yytext);                 if (opt_value == NULL)
      goto out_of_memory;                 parse_state = 2;                 break; 
 
--- 218,239 ----                 if (token == GUC_EQUALS)                     token = yylex(); 
!                 if (token != GUC_ID && token != GUC_STRING && token != GUC_INTEGER && token != GUC_REAL && token !=
GUC_UNQUOTED_STRING)                    goto parse_error;                 opt_value = strdup(yytext);
if(opt_value == NULL)                     goto out_of_memory;
 
+         if (token == GUC_STRING)
+         {
+             /* remove the beginning and ending quote/apostrophe */
+             /* first: shift the whole shooting match down one
+              character */
+             memmove(opt_value,opt_value+1,strlen(opt_value)-1);
+             /* second: null out the 2 characters we shifted */
+                         opt_value[strlen(opt_value)-2]='\0';
+             /* do the escape thing.  free()'s the strdup above */
+             opt_value=GUC_scanstr(opt_value);
+         }                 parse_state = 2;                 break; 
***************
*** 283,286 ****
--- 302,400 ---- yywrap(void) {     return 1;
+ }
+ 
+ /* ----------------
+  *        scanstr
+  *
+  * if the string passed in has escaped codes, map the escape codes to actual
+  * chars
+  *
+  * the string returned is palloc'd and should eventually be pfree'd by the
+  * caller!
+  * ----------------
+  */
+ 
+ char *
+ GUC_scanstr(char *s)
+ {
+     char       *newStr;
+     int            len,
+                 i,
+                 j;
+ 
+     if (s == NULL || s[0] == '\0')
+     {
+         if (s != NULL) free (s);
+         return strdup("");
+ 
+     }
+     len = strlen(s);
+ 
+     newStr = malloc(len + 1);    /* string cannot get longer */
+ 
+     for (i = 0, j = 0; i < len; i++)
+     {
+         if (s[i] == '\'')
+         {
+ 
+             /*
+              * Note: if scanner is working right, unescaped quotes can
+              * only appear in pairs, so there should be another character.
+              */
+             i++;
+             newStr[j] = s[i];
+         }
+         else if (s[i] == '\\')
+         {
+             i++;
+             switch (s[i])
+             {
+                 case 'b':
+                     newStr[j] = '\b';
+                     break;
+                 case 'f':
+                     newStr[j] = '\f';
+                     break;
+                 case 'n':
+                     newStr[j] = '\n';
+                     break;
+                 case 'r':
+                     newStr[j] = '\r';
+                     break;
+                 case 't':
+                     newStr[j] = '\t';
+                     break;
+                 case '0':
+                 case '1':
+                 case '2':
+                 case '3':
+                 case '4':
+                 case '5':
+                 case '6':
+                 case '7':
+                     {
+                         int            k;
+                         long        octVal = 0;
+ 
+                         for (k = 0;
+                              s[i + k] >= '0' && s[i + k] <= '7' && k < 3;
+                              k++)
+                             octVal = (octVal << 3) + (s[i + k] - '0');
+                         i += k - 1;
+                         newStr[j] = ((char) octVal);
+                     }
+                     break;
+                 default:
+                     newStr[j] = s[i];
+                     break;
+             }                    /* switch */
+         }                        /* s[i] == '\\' */
+         else
+             newStr[j] = s[i];
+         j++;
+     }
+     newStr[j] = '\0';
+     free(s);
+     return newStr; }

-- 
Larry Rosenman                      http://www.lerctr.org/~ler
Phone: +1 972-414-9812 (voice) Internet: ler@lerctr.org
US Mail: 1905 Steamboat Springs Drive, Garland, TX 75044-6749