Replace config file parser for "xl"

This provides a replacement config file parser for "xl" based on bison
and flex.

Benefits:
  * proper error reporting with line numbers
  * parser can understand nearly all "xm" configuration files directly
     (doesn't understand Python code but should do everything else)
  * parser also understands the ;-infested "xl" style files
  * removes the dependency on libconfig
  * better checking for certain kinds of mistakes
  * eliminates the strange "massage file and try again" code

This is intended to support all config files currently supported by
"xl" and almost all files supported by "xm".  (NB that whether a
feature works depends on the implementation of that feature in
xl/libxl of course.)

This patch also introduces a new library "libxlutil" which is mainly
for the benefit of "xl".  Users of libxl do not need to use libxlutil,
but they can do so if they want to parse "xl" files without being
"xl".

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Vincent Hanquez <vincent.hanquez@eu.citrix.com>

11 files changed, 702 insertions, 130 deletions

diff --git a/.hgignore b/.hgignore
index 92df552894..b40ca44c0c 100644
--- a/.hgignore
+++ b/.hgignore
@@ -180,7 +180,8 @@
 ^tools/libxen/libxenapi-
 ^tools/libxen/test/test_bindings$
 ^tools/libxen/test/test_event_handling$
-^tools/libxl/libconfig.*$
+^tools/libxl/libxlu_cfg_[yl]\.[ch]$
+^tools/libxl/libxlu_cfg_y\.output
 ^tools/libxl/xl$
 ^tools/libaio/src/.*\.ol$
 ^tools/libaio/src/.*\.os$
diff --git a/Config.mk b/Config.mk
index cd27af756d..1cebb31004 100644
--- a/Config.mk
+++ b/Config.mk
@@ -35,6 +35,9 @@ EXTRA_INCLUDES += $(EXTRA_PREFIX)/include
 EXTRA_LIB += $(EXTRA_PREFIX)/$(LIBLEAFDIR)
 endif
 
+BISON	?= bison
+FLEX	?= flex
+
 PYTHON      ?= python
 PYTHON_PREFIX_ARG ?= --prefix="$(PREFIX)"
 # The above requires that PREFIX contains *no spaces*. This variable is here
diff --git a/README b/README
index e32cd680f5..9869e911b0 100644
--- a/README
+++ b/README
@@ -49,6 +49,7 @@ provided by your Linux distributor:
     * bridge-utils package (/sbin/brctl)
     * iproute package (/sbin/ip)
     * hotplug or udev
+    * GNU bison and GNU flex
 
 [NB. Unless noted otherwise, all the following steps should be
 performed with root privileges.]
diff --git a/tools/libxl/Makefile b/tools/libxl/Makefile
index 3ddcd48513..dbf8c436d1 100644
--- a/tools/libxl/Makefile
+++ b/tools/libxl/Makefile
@@ -8,24 +8,40 @@ include $(XEN_ROOT)/tools/Rules.mk
 MAJOR = 1.0
 MINOR = 0
 
+XLUMAJOR = 1.0
+XLUMINOR = 0
+
 #CFLAGS += -Werror
 CFLAGS += -I. -fPIC
 CFLAGS += $(CFLAGS_libxenctrl) $(CFLAGS_libxenguest) $(CFLAGS_libxenstore)
 
 LIBS = $(LDFLAGS_libxenctrl) $(LDFLAGS_libxenguest) $(LDFLAGS_libxenstore)
 
-#LIBCONFIG_URL ?= http://www.hyperrealm.com/libconfig
-LIBCONFIG_URL = $(XEN_EXTFILES_URL)
-LIBCONFIG_SOURCE = libconfig-1.3.2
-LIBCONFIG_OUTPUT = $(LIBCONFIG_SOURCE)/.libs
-
 LIBXL_OBJS-y = osdeps.o
 LIBXL_OBJS = flexarray.o libxl.o libxl_dom.o libxl_exec.o libxl_xshelp.o libxl_device.o libxl_internal.o xenguest.o libxl_utils.o $(LIBXL_OBJS-y)
 
+AUTOINCS= libxlu_cfg_y.h libxlu_cfg_l.h
+AUTOSRCS= libxlu_cfg_y.c libxlu_cfg_l.c
+LIBXLU_OBJS = libxlu_cfg_y.o libxlu_cfg_l.o libxlu_cfg.o
+
 CLIENTS = xl
 
 .PHONY: all
-all: $(CLIENTS) libxenlight.so libxenlight.a
+all: $(CLIENTS) libxenlight.so libxenlight.a libxlutil.so libxlutil.a \
+	$(AUTOSRCS) $(AUTOINCS)
+
+$(AUTOINCS): $(AUTOSRCS)
+
+#%_y.h: %_y.c
+#%_l.h: %_l.c
+
+$(LIBXLU_OBJS): $(AUTOINCS)
+
+%.c: %.y
+	$(BISON) --output=$@ $<
+
+%.c: %.l
+	$(FLEX) --header-file=$*.h --outfile=$@ $<
 
 libxenlight.so: libxenlight.so.$(MAJOR)
 	ln -sf $< $@
@@ -39,18 +55,23 @@ libxenlight.so.$(MAJOR).$(MINOR): $(LIBXL_OBJS)
 libxenlight.a: $(LIBXL_OBJS)
 	$(AR) rcs libxenlight.a $^
 
-$(LIBCONFIG_SOURCE).tar.gz:
-	$(WGET) $(LIBCONFIG_URL)/$@
+libxlutil.so: libxlutil.so.$(XLUMAJOR)
+	ln -sf $< $@
+
+libxlutil.so.$(XLUMAJOR): libxlutil.so.$(XLUMAJOR).$(XLUMINOR)
+	ln -sf $< $@
+
+libxlutil.so.$(XLUMAJOR).$(XLUMINOR): $(LIBXLU_OBJS)
+	$(CC) $(CFLAGS) $(LDFLAGS) -Wl,$(SONAME_LDFLAG) -Wl,libxlutil.so.$(XLUMAJOR) $(SHLIB_CFLAGS) -o $@ $^
 
-$(LIBCONFIG_OUTPUT)/libconfig.so: $(LIBCONFIG_SOURCE).tar.gz
-	[ ! -d "$(LIBCONFIG_SOURCE)" ] && tar xzf $<
-	cd $(LIBCONFIG_SOURCE) && ./configure --prefix=$(PREFIX) --libdir=$(LIBDIR) --disable-cxx && $(MAKE)
+libxlutil.a: $(LIBXLU_OBJS)
+	$(AR) rcs libxlutil.a $^
 
-xl.o: $(LIBCONFIG_OUTPUT)/libconfig.so xl.c
-	$(CC) $(CFLAGS) -I$(LIBCONFIG_SOURCE) -c xl.c
+xl.o: xl.c
+	$(CC) $(CFLAGS) -c xl.c
 
-$(CLIENTS): xl.o libxenlight.so $(LIBCONFIG_OUTPUT)/libconfig.so
-	$(CC) $(LDFLAGS) -o $@ $< $(LIBS) -L . -lxenlight -L$(LIBCONFIG_OUTPUT) -lconfig
+$(CLIENTS): xl.o libxlutil.so libxenlight.so
+	$(CC) $(LDFLAGS) -o $@ $^ $(LIBS)
 
 .PHONY: install
 install: all
@@ -59,15 +80,17 @@ install: all
 	ln -sf libxenlight.so.$(MAJOR).$(MINOR) $(DESTDIR)$(LIBDIR)/libxenlight.so.$(MAJOR)
 	ln -sf libxenlight.so.$(MAJOR) $(DESTDIR)$(LIBDIR)/libxenlight.so
 	$(INSTALL_DATA) libxenlight.a $(DESTDIR)$(LIBDIR)
+	$(INSTALL_PROG) libxlutil.so.$(XLUMAJOR).$(XLUMINOR) $(DESTDIR)$(LIBDIR)
+	ln -sf libxlutil.so.$(XLUMAJOR).$(XLUMINOR) $(DESTDIR)$(LIBDIR)/libxlutil.so.$(XLUMAJOR)
+	ln -sf libxlutil.so.$(XLUMAJOR) $(DESTDIR)$(LIBDIR)/libxlutil.so
+	$(INSTALL_DATA) libxlutil.a $(DESTDIR)$(LIBDIR)
 	$(INSTALL_DATA) libxl.h $(DESTDIR)$(INCLUDEDIR)
-	cd $(LIBCONFIG_SOURCE) && DESTDIR=$(DESTDIR) $(MAKE) install
 
 .PHONY: clean
 clean:
 	$(RM) -f *.o *.so* *.a $(CLIENTS) $(DEPS)
-	$(RM) -rf $(LIBCONFIG_SOURCE)
+	$(RM) -f $(AUTOSRCS) $(AUTOINCS)
 
 distclean: clean
-	$(RM) -f $(LIBCONFIG_SOURCE).tar.gz
 
 -include $(DEPS)
diff --git a/tools/libxl/libxlu_cfg.c b/tools/libxl/libxlu_cfg.c
new file mode 100644
index 0000000000..632c371cf5
--- /dev/null
+++ b/tools/libxl/libxlu_cfg.c
@@ -0,0 +1,341 @@
+
+#include "libxlu_internal.h"
+#include "libxlu_cfg_y.h"
+#include "libxlu_cfg_l.h"
+#include "libxlu_cfg_i.h"
+
+XLU_Config *xlu_cfg_init(FILE *report, const char *report_filename) {
+    XLU_Config *cfg;
+
+    cfg= malloc(sizeof(*cfg));
+    if (!cfg) return 0;
+
+    cfg->report= report;
+    cfg->filename= strdup(report_filename);
+    if (!cfg->filename) { free(cfg); return 0; }
+
+    cfg->settings= 0;
+    return cfg;
+}
+
+int xlu_cfg_readfile(XLU_Config *cfg, const char *real_filename) {
+    CfgParseContext ctx;
+    FILE *f;
+    int e, r;
+
+    ctx.cfg= cfg;
+    ctx.err= 0;
+    ctx.lexerrlineno= -1;
+    
+    f= fopen(real_filename, "r");
+    if (!f) {
+        e= errno;
+        fprintf(cfg->report,"%s: unable to open configuration file: %s\n",
+                real_filename, strerror(e));
+        return e;
+    }
+
+    e= xlu__cfg_yylex_init_extra(&ctx, &ctx.scanner);
+    if (e) {
+        fprintf(cfg->report,"%s: unable to create scanner: %s\n",
+                cfg->filename, strerror(e));
+        return e;
+    }
+
+    xlu__cfg_yyrestart(f, ctx.scanner);
+
+    r= xlu__cfg_yyparse(&ctx);
+    if (r) assert(ctx.err);
+
+    xlu__cfg_yylex_destroy(ctx.scanner);
+    fclose(f);
+
+    return ctx.err;
+}
+
+void xlu__cfg_set_free(XLU_ConfigSetting *set) {
+    free(set->name);
+    free(set->values);
+    free(set);
+}
+
+void xlu_cfg_destroy(XLU_Config *cfg) {
+    XLU_ConfigSetting *set, *set_next;
+
+    for (set= cfg->settings;
+         set;
+         set= set_next) {
+        set_next= set->next;
+        xlu__cfg_set_free(set);
+    }
+    free(cfg->filename);
+    free(cfg);
+}
+
+static XLU_ConfigSetting *find(const XLU_Config *cfg, const char *n) {
+    XLU_ConfigSetting *set;
+
+    for (set= cfg->settings;
+         set;
+         set= set->next)
+        if (!strcmp(set->name, n))
+            return set;
+    return 0;
+}
+
+static int find_atom(const XLU_Config *cfg, const char *n,
+                     XLU_ConfigSetting **set_r) {
+    XLU_ConfigSetting *set;
+
+    set= find(cfg,n);
+    if (!set) return ESRCH;
+
+    if (set->avalues!=1) {
+        fprintf(cfg->report,
+                "%s:%d: warning: parameter `%s' is"
+                " a list but should be a single value\n",
+                cfg->filename, set->lineno, n);
+        return EINVAL;
+    }
+    *set_r= set;
+    return 0;
+}
+
+int xlu_cfg_get_string(const XLU_Config *cfg, const char *n,
+                       const char **value_r) {
+    XLU_ConfigSetting *set;
+    int e;
+
+    e= find_atom(cfg,n,&set);  if (e) return e;
+    *value_r= set->values[0];
+    return 0;
+}
+        
+int xlu_cfg_get_long(const XLU_Config *cfg, const char *n,
+                     long *value_r) {
+    long l;
+    XLU_ConfigSetting *set;
+    int e;
+    char *ep;
+
+    e= find_atom(cfg,n,&set);  if (e) return e;
+    errno= 0; l= strtol(set->values[0], &ep, 0);
+    e= errno;
+    if (errno) {
+        e= errno;
+        assert(e==EINVAL || e==ERANGE);
+        fprintf(cfg->report,
+                "%s:%d: warning: parameter `%s' could not be parsed"
+                " as a number: %s\n",
+                cfg->filename, set->lineno, n, strerror(e));
+        return e;
+    }
+    if (*ep || ep==set->values[0]) {
+        fprintf(cfg->report,
+                "%s:%d: warning: parameter `%s' is not a valid number\n",
+                cfg->filename, set->lineno, n);
+        return EINVAL;
+    }
+    *value_r= l;
+    return 0;
+}
+        
+
+int xlu_cfg_get_list(const XLU_Config *cfg, const char *n,
+                     XLU_ConfigList **list_r, int *entries_r) {
+    XLU_ConfigSetting *set;
+    set= find(cfg,n);  if (!set) return ESRCH;
+    if (set->avalues==1) {
+        fprintf(cfg->report,
+                "%s:%d: warning: parameter `%s' is a single value"
+                " but should be a list\n",
+                cfg->filename, set->lineno, n);
+        return EINVAL;
+    }
+    if (list_r) *list_r= set;
+    if (entries_r) *entries_r= set->nvalues;
+    return 0;
+}
+
+const char *xlu_cfg_get_listitem(const XLU_ConfigList *set, int entry) {
+    if (entry < 0 || entry >= set->nvalues) return 0;
+    return set->values[entry];
+}
+
+
+XLU_ConfigSetting *xlu__cfg_set_mk(CfgParseContext *ctx,
+                                   int alloc, char *atom) {
+    XLU_ConfigSetting *set= 0;
+
+    if (ctx->err) goto x;
+    assert(!!alloc == !!atom);
+
+    set= malloc(sizeof(*set));
+    if (!set) goto xe;
+
+    set->name= 0; /* tbd */
+    set->avalues= alloc;
+    
+    if (!alloc) {
+        set->nvalues= 0;
+        set->values= 0;
+    } else {
+        set->values= malloc(sizeof(*set->values) * alloc);
+        if (!set->values) goto xe;
+
+        set->nvalues= 1;
+        set->values[0]= atom;
+    }
+    return set;
+
+ xe:
+    ctx->err= errno;
+ x:
+    free(set);
+    free(atom);
+    return 0;
+}
+
+void xlu__cfg_set_add(CfgParseContext *ctx, XLU_ConfigSetting *set,
+                      char *atom) {
+    if (ctx->err) return;
+
+    assert(atom);
+    
+    if (set->nvalues >= set->avalues) {
+        int new_avalues;
+        char **new_values;
+        
+        if (set->avalues > INT_MAX / 100) { ctx->err= ERANGE; return; }
+        new_avalues= set->avalues * 4;
+        new_values= realloc(set->values,
+                            sizeof(*new_values) * new_avalues);
+        if (!new_values) { ctx->err= errno; free(atom); return; }
+        set->values= new_values;
+        set->avalues= new_avalues;
+    }
+    set->values[set->nvalues++]= atom;
+}
+
+void xlu__cfg_set_store(CfgParseContext *ctx, char *name,
+                        XLU_ConfigSetting *set, int lineno) {
+    if (ctx->err) return;
+
+    assert(name);
+    set->name= name;
+    set->lineno= lineno;
+    set->next= ctx->cfg->settings;
+    ctx->cfg->settings= set;
+}
+
+char *xlu__cfgl_strdup(CfgParseContext *ctx, const char *src) {
+    char *result;
+    
+    if (ctx->err) return 0;
+    result= strdup(src);
+    if (!result) ctx->err= errno;
+    return result;
+}
+
+char *xlu__cfgl_dequote(CfgParseContext *ctx, const char *src) {
+    char *result;
+    const char *p;
+    char *q;
+    int len, c, nc;
+
+    if (ctx->err) return 0;
+
+    len= strlen(src);
+    assert(len>=2 && src[0]==src[len-1]);
+
+    result= malloc(len-1);
+    if (!result) { ctx->err= errno; return 0; }
+
+    q= result;
+
+    for (p= src+1;
+         p < src+len-1;
+         ) {
+        c= *p++;
+        if (c=='\\') {
+            assert(p < src+len-1);
+            nc= *p++;
+            if (nc=='"' || nc=='\'' || nc=='\\') {
+                *q++= nc;
+            } else if (nc=='a') { *q++= '\007';
+            } else if (nc=='b') { *q++= '\010';
+            } else if (nc=='f') { *q++= '\014';
+            } else if (nc=='n') { *q++= '\n';
+            } else if (nc=='r') { *q++= '\r';
+            } else if (nc=='t') { *q++= '\t';
+            } else if (nc=='v') { *q++= '\013';
+            } else if (nc=='x') {
+
+#define NUMERIC_CHAR(minlen,maxlen,base,basetext) do{                        \
+                char numbuf[(maxlen)+1], *ep;                                \
+                unsigned long val;                                           \
+                                                                             \
+                strncpy(numbuf,p,(maxlen));                                  \
+                numbuf[(maxlen)]= 0;                                         \
+                val= strtoul(numbuf, &ep, (base));                           \
+                if (ep <= numbuf+(minlen)) {                                 \
+                    xlu__cfgl_lexicalerror(ctx,"invalid digit after"         \
+                         " backslash " basetext "numerical character escape" \
+                         " in quoted string");                               \
+                    ctx->err= EINVAL;                                        \
+                    goto x;                                                  \
+                }                                                            \
+                p += (ep - numbuf);                                          \
+ }while(0) 
+
+                p++;
+                NUMERIC_CHAR(2,2,16,"hex");
+            } else if (nc>='0' && nc<='7') {
+                NUMERIC_CHAR(1,3,10,"octal");
+            }
+            assert(p <= src+len-1);
+        } else {
+            *q++= c;
+        }
+    }
+
+ x:
+    *q++= 0;
+    return result;
+}
+
+void xlu__cfgl_lexicalerror(CfgParseContext *ctx, char const *msg) {
+    YYLTYPE loc;
+    loc.first_line= xlu__cfg_yyget_lineno(ctx->scanner);
+    xlu__cfg_yyerror(&loc, ctx, msg);
+    ctx->lexerrlineno= loc.first_line;
+}
+
+void xlu__cfg_yyerror(YYLTYPE *loc, CfgParseContext *ctx, char const *msg) {
+    const char *text, *newline;
+    int len, lineno;
+
+    lineno= loc->first_line;
+    if (lineno <= ctx->lexerrlineno) return;
+
+    text= xlu__cfg_yyget_text(ctx->scanner);
+    len= xlu__cfg_yyget_leng(ctx->scanner);
+    newline= "";
+    if (len>0 && text[len-1]=='\n') {
+        len--;
+        lineno--;
+        if (!len) {
+            newline= "<newline>";
+        }
+    }
+    while (len>0 && (text[len-1]=='\t' || text[len-1]==' ')) {
+        len--;
+    }
+
+    fprintf(ctx->cfg->report,
+            "%s:%d: config parsing error near %s%.*s%s%s: %s\n",
+            ctx->cfg->filename, lineno,
+            len?"`":"", len, text, len?"'":"", newline,
+            msg);
+    if (!ctx->err) ctx->err= EINVAL;
+}
diff --git a/tools/libxl/libxlu_cfg_i.h b/tools/libxl/libxlu_cfg_i.h
new file mode 100644
index 0000000000..f6b241cf09
--- /dev/null
+++ b/tools/libxl/libxlu_cfg_i.h
@@ -0,0 +1,25 @@
+#ifndef LIBXLU_CFG_I_H
+#define LIBXLU_CFG_I_H
+
+#include "libxlu_internal.h"
+#include "libxlu_cfg_y.h"
+
+void xlu__cfg_set_free(XLU_ConfigSetting *set);
+XLU_ConfigSetting *xlu__cfg_set_mk(CfgParseContext*, int alloc, char *atom);
+void xlu__cfg_set_add(CfgParseContext*, XLU_ConfigSetting *set, char *atom);
+void xlu__cfg_set_store(CfgParseContext*, char *name,
+                        XLU_ConfigSetting *set, int lineno);
+
+char *xlu__cfgl_strdup(CfgParseContext*, const char *src);
+char *xlu__cfgl_dequote(CfgParseContext*, const char *src);
+
+void xlu__cfg_yyerror(YYLTYPE *locp, CfgParseContext*, char const *msg);
+void xlu__cfgl_lexicalerror(CfgParseContext*, char const *msg);
+
+
+
+/* Why oh why does bison not declare this in its autogenerated .h ? */
+int xlu__cfg_yyparse(CfgParseContext *ctx);
+
+
+#endif /*LIBXLU_CFG_I_H*/
diff --git a/tools/libxl/libxlu_cfg_l.l b/tools/libxl/libxlu_cfg_l.l
new file mode 100644
index 0000000000..b3700281cb
--- /dev/null
+++ b/tools/libxl/libxlu_cfg_l.l
@@ -0,0 +1,74 @@
+/* -*- fundamental -*- */
+
+%{
+#include "libxlu_cfg_i.h"
+
+#define ctx ((CfgParseContext*)yyextra)
+#define YY_NO_INPUT
+
+#define GOT(x) do{                \
+    yylloc->first_line= yylineno; \
+    return (x);                   \
+  }while(0)
+
+%}
+
+%option warn
+%option nodefault
+%option batch
+%option 8bit
+%option yylineno
+%option noyywrap
+%option bison-bridge
+%option bison-locations
+%option reentrant
+%option prefix="xlu__cfg_yy"
+%option nounput
+
+%x lexerr
+
+%%
+
+[a-z][_0-9a-z]*         {
+                          yylval->string= xlu__cfgl_strdup(ctx,yytext);
+                          GOT(IDENT);
+                        }
+[0-9][0-9a-fx]*         {
+                          yylval->string= xlu__cfgl_strdup(ctx,yytext);
+                          GOT(NUMBER);
+                        }
+
+[ \t]
+
+,                       { GOT(','); }
+\[                      { GOT('['); }
+\]                      { GOT(']'); }
+\=                      { GOT('='); }
+\;                      { GOT(';'); }
+
+\n|\#.*\n               { yylloc->first_line= yylineno-1; return NEWLINE; }
+
+\'([^\'\\\n]|\\.)*\'    {
+                          yylval->string= xlu__cfgl_dequote(ctx,yytext);
+                          GOT(STRING);
+                        }
+\"([^\"\\\n]|\\.)*\"    {
+                          yylval->string= xlu__cfgl_dequote(ctx,yytext);
+                          GOT(STRING);
+                        }
+
+.                       {
+                          BEGIN(lexerr);
+                          yymore();
+                        }
+
+<lexerr>[^ \t\n]*|[ \t] {
+                          xlu__cfgl_lexicalerror(ctx,"lexical error");
+                          BEGIN(0);
+                        }
+
+<lexerr>\n              {
+                          xlu__cfgl_lexicalerror(ctx,"lexical error");
+                          BEGIN(0);
+                          GOT(NEWLINE);
+                        }
diff --git a/tools/libxl/libxlu_cfg_y.y b/tools/libxl/libxlu_cfg_y.y
new file mode 100644
index 0000000000..cdf8e0b66c
--- /dev/null
+++ b/tools/libxl/libxlu_cfg_y.y
@@ -0,0 +1,57 @@
+/* -*- fundamental -*- */
+
+%{
+#define YYLEX_PARAM ctx->scanner
+#include "libxlu_cfg_i.h"
+#include "libxlu_cfg_l.h"
+%}
+
+%union {
+  char *string;
+  XLU_ConfigSetting *setting;
+}
+
+%locations
+%pure-parser
+%defines
+%error-verbose
+%name-prefix="xlu__cfg_yy"
+%parse-param { CfgParseContext *ctx }
+%lex-param { void *scanner }
+
+%token <string>                IDENT STRING NUMBER NEWLINE
+%type <string>            atom
+%destructor { free($$); } atom IDENT STRING NUMBER
+
+%type <setting>                         value valuelist values
+%destructor { xlu__cfg_set_free($$); }  value valuelist values
+
+%%
+
+file: /* empty */
+ |     file setting           
+
+setting: IDENT '=' value      { xlu__cfg_set_store(ctx,$1,$3,@3.first_line); }
+                     endstmt
+ |      endstmt
+ |      error NEWLINE
+
+endstmt: NEWLINE
+ |      ';'
+
+value:  atom                         { $$= xlu__cfg_set_mk(ctx,1,$1); }
+ |      '[' nlok valuelist ']'       { $$= $3; }
+
+atom:   STRING                   { $$= $1; }
+ |      NUMBER                   { $$= $1; }
+
+valuelist: /* empty */           { $$= xlu__cfg_set_mk(ctx,0,0); }
+ |      values                  { $$= $1; }
+ |      values ',' nlok         { $$= $1; }
+
+values: atom nlok                  { $$= xlu__cfg_set_mk(ctx,2,$1); }
+ |      values ',' nlok atom nlok  { xlu__cfg_set_add(ctx,$1,$4); $$= $1; }
+
+nlok:
+        /* nothing */
+ |      nlok NEWLINE
diff --git a/tools/libxl/libxlu_internal.h b/tools/libxl/libxlu_internal.h
new file mode 100644
index 0000000000..fd7addcfd6
--- /dev/null
+++ b/tools/libxl/libxlu_internal.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2010      Citrix Ltd.
+ * Author Ian Jackson <ian.jackson@eu.citrix.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * 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 Lesser General Public License for more details.
+ */
+
+#ifndef LIBXLU_INTERNAL_H
+#define LIBXLU_INTERNAL_H
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+
+#define XLU_ConfigList XLU_ConfigSetting
+
+#include "libxlutil.h"
+
+struct XLU_ConfigSetting { /* transparent */
+    struct XLU_ConfigSetting *next;
+    char *name;
+    int nvalues, avalues; /* lists have avalues>1 */
+    char **values;
+    int lineno;
+};
+
+struct XLU_Config {
+    XLU_ConfigSetting *settings;
+    FILE *report;
+    char *filename;
+};
+
+typedef struct {
+    XLU_Config *cfg;
+    int err, lexerrlineno;
+    void *scanner;
+} CfgParseContext;
+
+#endif /*LIBXLU_INTERNAL_H*/
diff --git a/tools/libxl/libxlutil.h b/tools/libxl/libxlutil.h
new file mode 100644
index 0000000000..97b16aa134
--- /dev/null
+++ b/tools/libxl/libxlutil.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2010      Citrix Ltd.
+ * Author Ian Jackson <ian.jackson@eu.citrix.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; version 2.1 only. with the special
+ * exception on linking described in file LICENSE.
+ *
+ * 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 Lesser General Public License for more details.
+ */
+
+#ifndef LIBXLUTIL_H
+#define LIBXLUTIL_H
+
+#include <stdio.h>
+
+#include "libxl.h"
+
+/* Unless otherwise stated, all functions return an errno value. */
+typedef struct XLU_Config XLU_Config;
+typedef struct XLU_ConfigList XLU_ConfigList;
+
+XLU_Config *xlu_cfg_init(FILE *report, const char *report_filename);
+  /* 0 means we got ENOMEM. */
+  /* report_filename is copied; report is saved and must remain valid
+   *  until the Config is destroyed. */
+
+int xlu_cfg_readfile(XLU_Config*, const char *real_filename);
+  /* If this fails, then it is undefined behaviour to call xlu_cfg_get_...
+   * functions.  You have to just xlu_cfg_destroy. */
+ 
+void xlu_cfg_destroy(XLU_Config*);
+
+
+/* All of the following print warnings to "report" if there is a problem.
+ * Return values are:
+ *   0        OK
+ *   ESRCH    not defined
+ *   EINVAL   value found but wrong format for request (prints warning)
+ *   ERANGE   value out of range (from strtol)
+ */
+
+int xlu_cfg_get_string(const XLU_Config*, const char *n, const char **value_r);
+int xlu_cfg_get_long(const XLU_Config*, const char *n, long *value_r);
+
+int xlu_cfg_get_list(const XLU_Config*, const char *n,
+                     XLU_ConfigList **list_r /* may be 0 */,
+                     int *entries_r /* may be 0 */);
+  /* there is no need to free *list_r; lifetime is that of the XLU_Config */
+const char *xlu_cfg_get_listitem(const XLU_ConfigList*, int entry);
+  /* xlu_cfg_get_listitem cannot fail, except that if entry is
+   * out of range it returns 0 (not setting errno) */
+
+#endif /* LIBXLUTIL_H */
diff --git a/tools/libxl/xl.c b/tools/libxl/xl.c
index 823c8177ec..6e88c6ee6a 100644
--- a/tools/libxl/xl.c
+++ b/tools/libxl/xl.c
@@ -19,7 +19,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <libconfig.h>
 #include <unistd.h>
 #include <sys/time.h> /* for time */
 #include <getopt.h>
@@ -34,6 +33,7 @@
 
 #include "libxl.h"
 #include "libxl_utils.h"
+#include "libxlutil.h"
 
 #define UUID_FMT "%02hhx%02hhx%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx-%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
 
@@ -320,63 +320,6 @@ static void printf_info(libxl_domain_create_info *c_info,
     }
 }
 
-static char* compat_config_file(const char *filename)
-{
-    char t;
-    char *newfile = (char*) malloc(strlen(filename) + 4);
-    char *buf = (char *) malloc(2048);
-    int size = 2048, i;
-    FILE *s;
-    FILE *d;
-
-    sprintf(newfile, "%s.xl", filename);
-
-    s = fopen(filename, "r");
-    if (!s) {
-        perror("cannot open file for reading");
-        return NULL;
-    }
-    d = fopen(newfile, "w");
-    if (!d) {
-        fclose(s);
-        perror("cannot open file for writting");
-        return NULL;
-    }
-
-    while (!feof(s)) {
-        buf[0] = 0;
-        fgets(buf, size, s);
-        while (buf[strlen(buf) - 1] != '\n' && !feof(s)) {
-            size += 1024;
-            buf = realloc(buf, size + 1024);
-            fgets(buf + (size - 1025), 1025, s);
-        }
-        for (i = 0; i < strlen(buf); i++)
-            if (buf[i] == '\'')
-                buf[i] = '\"';
-        if (strchr(buf, '=') != NULL) {
-            if ((buf[strlen(buf) - 1] == '\n' && buf[strlen(buf) - 2] == ';') ||
-                    buf[strlen(buf) - 1] == ';') {
-                fputs(buf, d);
-            } else {
-                t = buf[strlen(buf) - 1];
-                buf[strlen(buf) - 1] = ';';
-                fputs(buf, d);
-                fputc(t, d);
-            }
-        } else if (buf[0] == '#' || buf[0] == ' ' || buf[0] == '\n') {
-            fputs(buf, d);
-        }
-    }
-
-    fclose(s);
-    fclose(d);
-
-    free(buf);
-
-    return newfile;
-}
-
 static void parse_config_file(const char *filename,
                               libxl_domain_create_info *c_info,
                               libxl_domain_build_info *b_info,
@@ -394,35 +337,33 @@ static void parse_config_file(const char *filename,
 {
     const char *buf;
     long l;
-    struct config_t config;
-    struct config_setting_t *vbds, *nics, *pcis, *cvfbs;
+    XLU_Config *config;
+    XLU_ConfigList *vbds, *nics, *pcis, *cvfbs;
     int pci_power_mgmt = 0;
     int pci_msitranslate = 1;
-    int i;
+    int i, e;
 
-    config_init (&config);
+    config= xlu_cfg_init(stderr, filename);
+    if (!config) {
+        fprintf(stderr, "Failed to allocate for configuration\n");
+        exit(1);
+    }
 
-    if (!config_read_file(&config, filename)) {
-        char *newfilename;
-        config_destroy(&config);
-        newfilename = compat_config_file(filename);
-        config_init (&config);
-        if (!config_read_file(&config, newfilename)) {
-            fprintf(stderr, "Failed to parse config file %s on line %d, try removing any embedded python code\n", config_error_text(&config), config_error_line(&config));
-            exit(1);
-        }
-        free(newfilename);
+    e= xlu_cfg_readfile (config, filename);
+    if (e) {
+        fprintf(stderr, "Failed to parse config file: %s\n", strerror(e));
+        exit(1);
     }
 
     init_create_info(c_info);
 
     c_info->hvm = 0;
-    if ((config_lookup_string (&config, "builder", &buf) == CONFIG_TRUE) &&
+    if (!xlu_cfg_get_string (config, "builder", &buf) &&
         !strncmp(buf, "hvm", strlen(buf)))
         c_info->hvm = 1;
 
     /* hap is missing */
-    if (config_lookup_string (&config, "name", &buf) == CONFIG_TRUE)
+    if (!xlu_cfg_get_string (config, "name", &buf))
         c_info->name = strdup(buf);
     else
         c_info->name = "test";
@@ -433,48 +374,48 @@ static void parse_config_file(const char *filename,
     init_build_info(b_info, c_info);
 
     /* the following is the actual config parsing with overriding values in the structures */
-    if (config_lookup_int (&config, "vcpus", &l) == CONFIG_TRUE)
+    if (!xlu_cfg_get_long (config, "vcpus", &l))
         b_info->max_vcpus = l;
 
-    if (config_lookup_int (&config, "memory", &l) == CONFIG_TRUE) {
+    if (!xlu_cfg_get_long (config, "memory", &l)) {
         b_info->max_memkb = l * 1024;
         b_info->target_memkb = b_info->max_memkb;
     }
 
-    if (config_lookup_int (&config, "shadow_memory", &l) == CONFIG_TRUE)
+    if (!xlu_cfg_get_long (config, "shadow_memory", &l))
         b_info->shadow_memkb = l * 1024;
 
-    if (config_lookup_int (&config, "videoram", &l) == CONFIG_TRUE)
+    if (!xlu_cfg_get_long (config, "videoram", &l))
         b_info->video_memkb = l * 1024;
 
-    if (config_lookup_string (&config, "kernel", &buf) == CONFIG_TRUE)
+    if (!xlu_cfg_get_string (config, "kernel", &buf))
         b_info->kernel = strdup(buf);
 
     if (c_info->hvm == 1) {
-        if (config_lookup_int (&config, "pae", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "pae", &l))
             b_info->u.hvm.pae = l;
-        if (config_lookup_int (&config, "apic", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "apic", &l))
             b_info->u.hvm.apic = l;
-        if (config_lookup_int (&config, "acpi", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "acpi", &l))
             b_info->u.hvm.acpi = l;
-        if (config_lookup_int (&config, "nx", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "nx", &l))
             b_info->u.hvm.nx = l;
-        if (config_lookup_int (&config, "viridian", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "viridian", &l))
             b_info->u.hvm.viridian = l;
     } else {
         char *cmdline;
-        if (config_lookup_string (&config, "root", &buf) == CONFIG_TRUE) {
+        if (!xlu_cfg_get_string (config, "root", &buf)) {
             asprintf(&cmdline, "root=%s", buf);
             b_info->u.pv.cmdline = cmdline;
         }
-        if (config_lookup_string (&config, "ramdisk", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "ramdisk", &buf))
             b_info->u.pv.ramdisk = strdup(buf);
     }
 
-    if ((vbds = config_lookup (&config, "disk")) != NULL) {
+    if (!xlu_cfg_get_list (config, "disk", &vbds, 0)) {
         *num_disks = 0;
         *disks = NULL;
-        while ((buf = config_setting_get_string_elem (vbds, *num_disks)) != NULL) {
+        while ((buf = xlu_cfg_get_listitem (vbds, *num_disks)) != NULL) {
             char *buf2 = strdup(buf);
             char *p, *p2;
             *disks = (libxl_device_disk *) realloc(*disks, sizeof (libxl_device_disk) * ((*num_disks) + 1));
@@ -530,10 +471,10 @@ static void parse_config_file(const char *filename,
         }
     }
 
-    if ((nics = config_lookup (&config, "vif")) != NULL) {
+    if (!xlu_cfg_get_list (config, "vif", &nics, 0)) {
         *num_vifs = 0;
         *vifs = NULL;
-        while ((buf = config_setting_get_string_elem (nics, *num_vifs)) != NULL) {
+        while ((buf = xlu_cfg_get_listitem (nics, *num_vifs)) != NULL) {
             char *buf2 = strdup(buf);
             char *p, *p2;
             *vifs = (libxl_device_nic *) realloc(*vifs, sizeof (libxl_device_nic) * ((*num_vifs) + 1));
@@ -593,12 +534,12 @@ skip:
         }
     }
 
-    if ((cvfbs = config_lookup (&config, "vfb")) != NULL) {
+    if (!xlu_cfg_get_list (config, "vfb", &cvfbs, 0)) {
         *num_vfbs = 0;
         *num_vkbs = 0;
         *vfbs = NULL;
         *vkbs = NULL;
-        while ((buf = config_setting_get_string_elem (cvfbs, *num_vfbs)) != NULL) {
+        while ((buf = xlu_cfg_get_listitem (cvfbs, *num_vfbs)) != NULL) {
             char *buf2 = strdup(buf);
             char *p, *p2;
             *vfbs = (libxl_device_vfb *) realloc(*vfbs, sizeof(libxl_device_vfb) * ((*num_vfbs) + 1));
@@ -643,16 +584,16 @@ skip_vfb:
         }
     }
 
-    if (config_lookup_int (&config, "pci_msitranslate", &l) == CONFIG_TRUE)
+    if (!xlu_cfg_get_long (config, "pci_msitranslate", &l))
         pci_msitranslate = l;
 
-    if (config_lookup_int (&config, "pci_power_mgmt", &l) == CONFIG_TRUE)
+    if (!xlu_cfg_get_long (config, "pci_power_mgmt", &l))
         pci_power_mgmt = l;
 
-    if ((pcis = config_lookup (&config, "pci")) != NULL) {
+    if (xlu_cfg_get_list (config, "pci", &pcis, 0)) {
         *num_pcidevs = 0;
         *pcidevs = NULL;
-        while ((buf = config_setting_get_string_elem (pcis, *num_pcidevs)) != NULL) {
+        while ((buf = xlu_cfg_get_listitem (pcis, *num_pcidevs)) != NULL) {
             unsigned int domain = 0, bus = 0, dev = 0, func = 0, vdevfn = 0;
             char *buf2 = strdup(buf);
             char *p;
@@ -690,37 +631,37 @@ skip_pci:
         init_dm_info(dm_info, c_info, b_info);
 
         /* then process config related to dm */
-        if (config_lookup_string (&config, "device_model", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "device_model", &buf))
             dm_info->device_model = strdup(buf);
-        if (config_lookup_int (&config, "stdvga", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "stdvga", &l))
             dm_info->stdvga = l;
-        if (config_lookup_int (&config, "vnc", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "vnc", &l))
             dm_info->vnc = l;
-        if (config_lookup_string (&config, "vnclisten", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "vnclisten", &buf))
             dm_info->vnclisten = strdup(buf);
-        if (config_lookup_int (&config, "vncdisplay", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "vncdisplay", &l))
             dm_info->vncdisplay = l;
-        if (config_lookup_int (&config, "vncunused", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "vncunused", &l))
             dm_info->vncunused = l;
-        if (config_lookup_string (&config, "keymap", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "keymap", &buf))
             dm_info->keymap = strdup(buf);
-        if (config_lookup_int (&config, "sdl", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "sdl", &l))
             dm_info->sdl = l;
-        if (config_lookup_int (&config, "opengl", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "opengl", &l))
             dm_info->opengl = l;
-        if (config_lookup_int (&config, "nographic", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "nographic", &l))
             dm_info->nographic = l;
-        if (config_lookup_string (&config, "serial", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "serial", &buf))
             dm_info->serial = strdup(buf);
-        if (config_lookup_string (&config, "boot", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "boot", &buf))
             dm_info->boot = strdup(buf);
-        if (config_lookup_int (&config, "usb", &l) == CONFIG_TRUE)
+        if (!xlu_cfg_get_long (config, "usb", &l))
             dm_info->usb = l;
-        if (config_lookup_string (&config, "usbdevice", &buf) == CONFIG_TRUE)
+        if (!xlu_cfg_get_string (config, "usbdevice", &buf))
             dm_info->usbdevice = strdup(buf);
     }
 
-    config_destroy(&config);
+    xlu_cfg_destroy(config);
 }
 
 #define MUST( call ) ({                                                 \