Rewrite ProcessConfigFile() to avoid misbehavior at EOF, as per report

from Andrus Moor.  The former state-machine-style coding wasn't actually
doing much except obscuring the control flow, and it didn't extend
readily to fix this case, so I just took it out.  Also, add a
YY_FLUSH_BUFFER call to ensure the lexer is reset correctly if the
previous scan failed partway through the file.

diff --git a/src/backend/utils/misc/guc-file.l b/src/backend/utils/misc/guc-file.l
index f5fed2e267ead0ec7054d8d568a3168ea2c2f8e0..69855a2d045964daf62ad0e831232bba83893ad6 100644 (file)
--- a/src/backend/utils/misc/guc-file.l
+++ b/src/backend/utils/misc/guc-file.l
@@ -4,7 +4,7 @@
  *
  * Copyright (c) 2000-2005, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.32 2005/09/21 20:33:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/misc/guc-file.l,v 1.33 2006/01/01 19:52:40 tgl Exp $
  */
 
 %{
@@ -126,7 +126,7 @@ void
 ProcessConfigFile(GucContext context)
 {
        int                     elevel;
-       int                     token, parse_state;
+       int                     token;
        char       *opt_name, *opt_value;
        struct name_value_pair *item, *head, *tail;
        FILE       *fp;
@@ -144,94 +144,93 @@ ProcessConfigFile(GucContext context)
        else
                elevel = ERROR;
 
-    fp = AllocateFile(ConfigFileName, "r");
-    if (!fp)
-    {
+       fp = AllocateFile(ConfigFileName, "r");
+       if (!fp)
+       {
                ereport(elevel,
                                (errcode_for_file_access(),
                                 errmsg("could not open configuration file \"%s\": %m",
                                                ConfigFileName)));
                return;
-    }
+       }
 
        /*
         * Parse
         */
        yyin = fp;
-    parse_state = 0;
+       YY_FLUSH_BUFFER;                        /* in case we abandoned a prior scan */
        head = tail = NULL;
        opt_name = opt_value = NULL;
        ConfigFileLineno = 1;
 
-    while ((token = yylex()))
+       /* This loop iterates once per logical line */
+       while ((token = yylex()))
        {
-        switch(parse_state)
-        {
-            case 0: /* no previous input */
-                if (token == GUC_EOL) /* empty line */
-                    continue;
-                if (token != GUC_ID && token != GUC_QUALIFIED_ID)
-                    goto parse_error;
-                opt_name = pstrdup(yytext);
-                parse_state = 1;
-                break;
-
-            case 1: /* found name */
-                /* ignore equals sign */
-                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;
-                               if (token == GUC_STRING)        /* strip quotes and escapes */
-                                       opt_value = GUC_scanstr(yytext);
-                               else
-                                       opt_value = pstrdup(yytext);
-                parse_state = 2;
-                break;
-
-            case 2: /* now we'd like an end of line */
-                               if (token != GUC_EOL)
-                                       goto parse_error;
-
-                               if (strcmp(opt_name, "custom_variable_classes") == 0)
-                               {
-                                       /*
-                                        * This variable must be processed first as it controls
-                                        * the validity of other variables; so apply immediately.
-                                        */
-                                       if (!set_config_option(opt_name, opt_value, context,
-                                                                                  PGC_S_FILE, false, true))
-                                       {
-                                               pfree(opt_name);
-                                               pfree(opt_value);
-                                               FreeFile(fp);
-                                               goto cleanup_exit;
-                                       }
-                                       pfree(opt_name);
-                                       pfree(opt_value);
-                               }
-                               else
-                               {
-                                       /* append to list */
-                                       item = palloc(sizeof *item);
-                                       item->name = opt_name;
-                                       item->value = opt_value;
-                                       item->next = NULL;
-                                       if (!head)
-                                               head = item;
-                                       else
-                                               tail->next = item;
-                                       tail = item;
-                               }
-
-                parse_state = 0;
-                break;
-        }
+               if (token == GUC_EOL)   /* empty or comment line */
+                       continue;
+
+               /* first token on line is option name */
+               if (token != GUC_ID && token != GUC_QUALIFIED_ID)
+                       goto parse_error;
+               opt_name = pstrdup(yytext);
+
+               /* next we have an optional equal sign; discard if present */
+               token = yylex();
+               if (token == GUC_EQUALS)
+                       token = yylex();
+
+               /* now we must have the option value */
+               if (token != GUC_ID &&
+                       token != GUC_STRING && 
+                       token != GUC_INTEGER && 
+                       token != GUC_REAL && 
+                       token != GUC_UNQUOTED_STRING)
+                       goto parse_error;
+               if (token == GUC_STRING)        /* strip quotes and escapes */
+                       opt_value = GUC_scanstr(yytext);
+               else
+                       opt_value = pstrdup(yytext);
+
+               /* now we'd like an end of line, or possibly EOF */
+               token = yylex();
+               if (token != GUC_EOL && token != 0)
+                       goto parse_error;
+
+               /* OK, save the option name and value */
+               if (strcmp(opt_name, "custom_variable_classes") == 0)
+               {
+                       /*
+                        * This variable must be processed first as it controls
+                        * the validity of other variables; so apply immediately.
+                        */
+                       if (!set_config_option(opt_name, opt_value, context,
+                                                                  PGC_S_FILE, false, true))
+                       {
+                               pfree(opt_name);
+                               pfree(opt_value);
+                               FreeFile(fp);
+                               goto cleanup_exit;
+                       }
+                       pfree(opt_name);
+                       pfree(opt_value);
+               }
+               else
+               {
+                       /* append to list */
+                       item = palloc(sizeof *item);
+                       item->name = opt_name;
+                       item->value = opt_value;
+                       item->next = NULL;
+                       if (!head)
+                               head = item;
+                       else
+                               tail->next = item;
+                       tail = item;
+               }
+
+               /* break out of loop if read EOF, else loop for next line */
+               if (token == 0)
+                       break;
        }
 
        FreeFile(fp);
@@ -239,14 +238,14 @@ ProcessConfigFile(GucContext context)
        /*
         * Check if all options are valid
         */
-    for(item = head; item; item=item->next)
+       for(item = head; item; item=item->next)
        {
                if (!set_config_option(item->name, item->value, context,
                                                           PGC_S_FILE, false, false))
                        goto cleanup_exit;
        }
 
-    /* If we got here all the options parsed okay, so apply them. */
+       /* If we got here all the options parsed okay, so apply them. */
        for(item = head; item; item=item->next)
        {
                set_config_option(item->name, item->value, context,
@@ -260,7 +259,7 @@ ProcessConfigFile(GucContext context)
  parse_error:
        FreeFile(fp);
        free_name_value_list(head);
-       if (token == GUC_EOL)
+       if (token == GUC_EOL || token == 0)
                ereport(elevel,
                                (errcode(ERRCODE_SYNTAX_ERROR),
                                 errmsg("syntax error in file \"%s\" line %u, near end of line",