Subject: Re: kern/29133: Fault in Kernelfunction findsym
To: None <cube@netbsd.org, gnats-admin@netbsd.org, netbsd-bugs@netbsd.org>
From: Quentin Garnier <cube@cubidou.net>
List: netbsd-bugs
Date: 01/27/2005 21:17:01
The following reply was made to PR kern/29133; it has been noted by GNATS.
From: Quentin Garnier <cube@cubidou.net>
To: gnats-bugs@netbsd.org
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org,
netbsd-bugs@netbsd.org
Subject: Re: kern/29133: Fault in Kernelfunction findsym
Date: Thu, 27 Jan 2005 22:16:39 +0100
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On Thu, Jan 27, 2005 at 01:54:00PM +0000, kessi@teles.de wrote:
> >Number: 29133
> >Category: kern
> >Synopsis: Fault in Kernelfunction findsym
Please try the attached patch.
--=20
Quentin Garnier - cube@cubidou.net - cube@NetBSD.org
"Commala-come-five! / Even when the shadows rise!
To see the world and walk the world / Makes ya glad to be alive."
Susannah's Song, The Dark Tower VI, Stephen King, 2004.
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Index: ddb/db_sym.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /cvsroot/src/sys/ddb/db_sym.c,v
retrieving revision 1.45
diff -u -r1.45 db_sym.c
--- ddb/db_sym.c 17 Nov 2003 10:16:18 -0000 1.45
+++ ddb/db_sym.c 27 Jan 2005 21:13:42 -0000
@@ -109,12 +109,12 @@
}
#endif
db_symsplit(name, &mod, &sym);
- if (ksyms_getval_from_kernel(mod, sym, &uval, KSYMS_EXTERN) =3D=3D 0) {
+ if (ksyms_getval(mod, sym, &uval, KSYMS_EXTERN) =3D=3D 0) {
val =3D (long) uval;
*valuep =3D (db_expr_t)val;
return TRUE;
}
- if (ksyms_getval_from_kernel(mod, sym, &uval, KSYMS_ANY) =3D=3D 0) {
+ if (ksyms_getval(mod, sym, &uval, KSYMS_ANY) =3D=3D 0) {
val =3D (long) uval;
*valuep =3D (db_expr_t)val;
return TRUE;
@@ -229,7 +229,7 @@
#endif
=20
if (ksyms_getname(&mod, &sym, (vaddr_t)val, strategy) =3D=3D 0) {
- (void)ksyms_getval_from_kernel(mod, sym, &naddr, KSYMS_ANY);
+ (void)ksyms_getval(mod, sym, &naddr, KSYMS_ANY);
diff =3D val - (db_addr_t)naddr;
ret =3D (db_sym_t)naddr;
} else
@@ -337,7 +337,7 @@
#endif
if (ksyms_getname(&mod, &name, (vaddr_t)off,
strategy|KSYMS_CLOSEST) =3D=3D 0) {
- (void)ksyms_getval_from_kernel(mod, name, &val, KSYMS_ANY);
+ (void)ksyms_getval(mod, name, &val, KSYMS_ANY);
if (((off - val) < db_maxoff) && val) {
sprintf(buf, "%s:%s", mod, name);
if (off - val) {
@@ -407,7 +407,7 @@
#endif
if (ksyms_getname(&mod, &name, (vaddr_t)off,
strategy|KSYMS_CLOSEST) =3D=3D 0) {
- (void)ksyms_getval_from_kernel(mod, name, &uval, KSYMS_ANY);
+ (void)ksyms_getval(mod, name, &uval, KSYMS_ANY);
val =3D (long) uval;
if (((off - val) < db_maxoff) && val) {
(*pr)("%s:%s", mod, name);
Index: kern/kern_ksyms.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /cvsroot/src/sys/kern/kern_ksyms.c,v
retrieving revision 1.21
diff -u -r1.21 kern_ksyms.c
--- kern/kern_ksyms.c 19 Feb 2004 03:42:01 -0000 1.21
+++ kern/kern_ksyms.c 27 Jan 2005 21:13:42 -0000
@@ -269,12 +269,12 @@
* Finds a certain symbol name in a certain symbol table.
*/
static Elf_Sym *
-findsym(char *name, struct symtab *table, int userreq)
+findsym(char *name, struct symtab *table)
{
Elf_Sym *start =3D table->sd_symstart;
int i, sz =3D table->sd_symsize/sizeof(Elf_Sym);
char *np;
- caddr_t realstart =3D table->sd_strstart - (userreq ? 0 : table->sd_usrof=
fset);
+ caddr_t realstart =3D table->sd_strstart - table->sd_usroffset;
=20
#ifdef USE_PTREE
if (table =3D=3D &kernel_symtab && (i =3D ptree_find(name)) !=3D 0)
@@ -497,7 +497,7 @@
* Returns 0 if success or ENOENT if no such entry.
*/
int
-ksyms_getval(const char *mod, char *sym, unsigned long *val, int type, int=
userreq)
+ksyms_getval(const char *mod, char *sym, unsigned long *val, int type)
{
struct symtab *st;
Elf_Sym *es;
@@ -513,7 +513,7 @@
CIRCLEQ_FOREACH(st, &symtab_queue, sd_queue) {
if (mod && strcmp(st->sd_name, mod))
continue;
- if ((es =3D findsym(sym, st, userreq)) =3D=3D NULL)
+ if ((es =3D findsym(sym, st)) =3D=3D NULL)
continue;
=20
/* Skip if bad binding */
@@ -583,6 +583,17 @@
#if NKSYMS
static int symsz, strsz;
=20
+/*
+ * In case we exposing the symbol table to the userland using the pseudo-
+ * device /dev/ksyms, it is easier to provide all the tables as one.
+ * However, it means we have to change all the st_name fields for the
+ * symbols so they match the ELF image that the userland will read
+ * through the device.
+ *
+ * The actual (correct) value of st_name is preserved through a global
+ * offset stored in the symbol table structure.
+ */
+
static void
ksyms_sizes_calc(void)
{ =20
@@ -732,8 +743,7 @@
continue;
=09
/* Check if the symbol exists */
- if (ksyms_getval_from_kernel(NULL, symname,
- &rval, KSYMS_EXTERN) =3D=3D 0) {
+ if (ksyms_getval(NULL, symname, &rval, KSYMS_EXTERN) =3D=3D 0) {
/* Check (and complain) about differing values */
if (sym[i].st_value !=3D rval) {
if (specialsym(symname)) {
@@ -777,8 +787,7 @@
continue;
=09
/* Check if the symbol exists */
- if (ksyms_getval_from_kernel(NULL, symname,
- &rval, KSYMS_EXTERN) =3D=3D 0) {
+ if (ksyms_getval(NULL, symname, &rval, KSYMS_EXTERN) =3D=3D 0) {
if ((sym[i].st_value !=3D rval) && specialsym(symname)) {
addsym(&info, &sym[i], symname, mod);
}
@@ -1135,7 +1144,7 @@
*/
if ((error =3D copyinstr(kg->kg_name, str, ksyms_maxlen, NULL)))
break;
- if ((error =3D ksyms_getval_from_userland(NULL, str, &val, KSYMS_EXTERN)=
))
+ if ((error =3D ksyms_getval(NULL, str, &val, KSYMS_EXTERN)))
break;
error =3D copyout(&val, kg->kg_value, sizeof(long));
break;
@@ -1148,7 +1157,7 @@
if ((error =3D copyinstr(kg->kg_name, str, ksyms_maxlen, NULL)))
break;
CIRCLEQ_FOREACH(st, &symtab_queue, sd_queue) {
- if ((sym =3D findsym(str, st, 1)) =3D=3D NULL) /* from userland */
+ if ((sym =3D findsym(str, st)) =3D=3D NULL) /* from userland */
continue;
=20
/* Skip if bad binding */
@@ -1158,6 +1167,12 @@
}
break;
}
+ /*
+ * XXX which value of sym->st_name should be returned? The real
+ * one, or the one that matches what reading /dev/ksyms get?
+ *
+ * Currently, we're returning the /dev/ksyms one.
+ */
if (sym !=3D NULL)
error =3D copyout(sym, kg->kg_sym, sizeof(Elf_Sym));
else
Index: kern/kern_sysctl.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /cvsroot/src/sys/kern/kern_sysctl.c,v
retrieving revision 1.169.2.6
diff -u -r1.169.2.6 kern_sysctl.c
--- kern/kern_sysctl.c 14 May 2004 06:18:39 -0000 1.169.2.6
+++ kern/kern_sysctl.c 27 Jan 2005 21:13:44 -0000
@@ -1006,8 +1006,8 @@
sizeof(symname), &symlen);
if (error)
return (error);
- error =3D ksyms_getval_from_kernel(NULL,
- symname, &symaddr, KSYMS_EXTERN);
+ error =3D ksyms_getval(NULL, symname,
+ &symaddr, KSYMS_EXTERN);
if (error)
return (error); /* EINVAL? */
nnode.sysctl_data =3D (void*)symaddr;
Index: sys/ksyms.h
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
RCS file: /cvsroot/src/sys/sys/ksyms.h,v
retrieving revision 1.8
diff -u -r1.8 ksyms.h
--- sys/ksyms.h 17 Nov 2003 10:16:18 -0000 1.8
+++ sys/ksyms.h 27 Jan 2005 21:13:44 -0000
@@ -60,9 +60,7 @@
* Prototypes
*/
int ksyms_getname(const char **, char **, vaddr_t, int);
-int ksyms_getval(const char *, char *, unsigned long *, int, int);
-#define ksyms_getval_from_kernel(a,b,c,d) ksyms_getval(a,b,c,d,0)
-#define ksyms_getval_from_userland(a,b,c,d) ksyms_getval(a,b,c,d,1)
+int ksyms_getval(const char *, char *, unsigned long *, int);
int ksyms_addsymtab(const char *, void *, vsize_t, char *, vsize_t);
int ksyms_delsymtab(const char *);
int ksyms_rensymtab(const char *, const char*);
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