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authorjmallett <jmallett@FreeBSD.org>2012-03-29 03:13:43 +0000
committerjmallett <jmallett@FreeBSD.org>2012-03-29 03:13:43 +0000
commit0b5862156580ae2abf520982aca1e1085730d500 (patch)
treeea722f27f2dcefc1a0ae7ba943dd42b20b9207a5
parent299c847f0b109bdb3c5e20596f1ba2dc6f72e468 (diff)
downloadFreeBSD-src-0b5862156580ae2abf520982aca1e1085730d500.zip
FreeBSD-src-0b5862156580ae2abf520982aca1e1085730d500.tar.gz
Fix 32-bit libgeom consumers run on 64-bit kernels with COMPAT_FREEBSD32.
Kernel pointer values are used as opaque unique identifiers, which are then used to reconstruct references between various providers, classes, etc., inside libgeom from the source XML. Unfortunately, they're converted to pointer-width integers (in the form of pointers) to do this, and 32-bit userland pointers cannot hold sensible representations (however opaque) of 64-bit kernel pointers on all systems. In the case where the leading bits are zero and 32 distinct bits of pointer can be identified, this will happen to work. On systems where the upper 32-bits of kernel pointers are non-zero and the same for all kernel pointers, this will result in double frees and all kinds of bizarre crashes and linkage between objects inside libgeom. To mitigate this problem, treat the opaque identifiers in the XML as C strings instead, and internalize them to give unique and consistent per-object pointer values in userland for each identifier in the XML. This allows us to keep the libgeom logic the same with only minor changes to initial setup and parsing. It might be more sensible for speed reasons to treat the identifiers as numbers of a large size (uintmax_t, say) rather than strings, but strings seem fine for now. (As an added side-effect, this makes it slightly easier to identify unresolved references, but nothing has been added to inform the user of those.)
-rw-r--r--lib/libgeom/geom_xml2tree.c108
-rw-r--r--lib/libgeom/libgeom.h3
2 files changed, 82 insertions, 29 deletions
diff --git a/lib/libgeom/geom_xml2tree.c b/lib/libgeom/geom_xml2tree.c
index 24315cd..eb9a385 100644
--- a/lib/libgeom/geom_xml2tree.c
+++ b/lib/libgeom/geom_xml2tree.c
@@ -55,9 +55,56 @@ struct mystate {
int level;
struct sbuf *sbuf[20];
struct gconf *config;
- int nident;
+ unsigned nident;
};
+static void *
+internalize_ident(struct mystate *mt, const char *element, const char *str)
+{
+ struct gident *gip;
+ unsigned i;
+
+ if (mt->nident != 0 && mt->mesh->lg_ident == NULL) {
+ warn("Cannot continue due to previous memory exhaustion.");
+ return (NULL);
+ }
+
+ for (i = 0; i < mt->nident; i++) {
+ if (strcmp(mt->mesh->lg_ident[i].lg_id, str) != 0)
+ continue;
+ return ((void *)(uintptr_t)(i + 1));
+ }
+
+ i = mt->nident;
+ mt->nident++;
+ mt->mesh->lg_ident = reallocf(mt->mesh->lg_ident, (mt->nident + 1) * sizeof mt->mesh->lg_ident[0]);
+ if (mt->mesh->lg_ident == NULL) {
+ warn("Cannot allocate memory during processing of '%s' "
+ "element for identifier '%s'", element, str);
+ return (NULL);
+ }
+
+ gip = &mt->mesh->lg_ident[i];
+ gip->lg_id = strdup(str);
+ if (gip->lg_id == NULL) {
+ free(mt->mesh->lg_ident);
+ mt->mesh->lg_ident = NULL;
+ warn("Cannot allocate memory during processing of '%s' "
+ "element for identifier '%s'", element, str);
+ return (NULL);
+ }
+ gip->lg_ptr = NULL;
+ gip->lg_what = ISUNRESOLVED;
+
+ /* Terminator entry. */
+ gip = &mt->mesh->lg_ident[i + 1];
+ gip->lg_id = NULL;
+ gip->lg_ptr = NULL;
+ gip->lg_what = ISUNRESOLVED;
+
+ return ((void *)(uintptr_t)(i + 1));
+}
+
static void
StartElement(void *userData, const char *name, const char **attr)
{
@@ -73,10 +120,9 @@ StartElement(void *userData, const char *name, const char **attr)
ref = NULL;
for (i = 0; attr[i] != NULL; i += 2) {
if (!strcmp(attr[i], "id")) {
- id = (void *)strtoul(attr[i + 1], NULL, 0);
- mt->nident++;
+ id = internalize_ident(mt, name, attr[i + 1]);
} else if (!strcmp(attr[i], "ref")) {
- ref = (void *)strtoul(attr[i + 1], NULL, 0);
+ ref = internalize_ident(mt, name, attr[i + 1]);
} else
printf("%*.*s[%s = %s]\n",
mt->level + 1, mt->level + 1, "",
@@ -317,11 +363,16 @@ CharData(void *userData , const XML_Char *s , int len)
struct gident *
geom_lookupid(struct gmesh *gmp, const void *id)
{
- struct gident *gip;
+ unsigned i;
- for (gip = gmp->lg_ident; gip->lg_id != NULL; gip++)
- if (gip->lg_id == id)
- return (gip);
+ if (gmp->lg_ident == NULL)
+ return (NULL);
+
+ for (i = 0; gmp->lg_ident[i].lg_id != NULL; i++) {
+ if (i + 1 != (unsigned)(uintptr_t)id)
+ continue;
+ return (&gmp->lg_ident[i]);
+ }
return (NULL);
}
@@ -334,6 +385,7 @@ geom_xml2tree(struct gmesh *gmp, char *p)
struct ggeom *ge;
struct gprovider *pr;
struct gconsumer *co;
+ struct gident *gip;
int i;
memset(gmp, 0, sizeof *gmp);
@@ -356,33 +408,30 @@ geom_xml2tree(struct gmesh *gmp, char *p)
free(mt);
return (-1);
}
- gmp->lg_ident = calloc(sizeof *gmp->lg_ident, mt->nident + 1);
- free(mt);
- if (gmp->lg_ident == NULL)
+ if (gmp->lg_ident == NULL && mt->nident != 0) {
+ free(mt);
return (ENOMEM);
- i = 0;
+ }
+ free(mt);
/* Collect all identifiers */
LIST_FOREACH(cl, &gmp->lg_class, lg_class) {
- gmp->lg_ident[i].lg_id = cl->lg_id;
- gmp->lg_ident[i].lg_ptr = cl;
- gmp->lg_ident[i].lg_what = ISCLASS;
- i++;
+ gip = geom_lookupid(gmp, cl->lg_id);
+ gip->lg_ptr = cl;
+ gip->lg_what = ISCLASS;
+
LIST_FOREACH(ge, &cl->lg_geom, lg_geom) {
- gmp->lg_ident[i].lg_id = ge->lg_id;
- gmp->lg_ident[i].lg_ptr = ge;
- gmp->lg_ident[i].lg_what = ISGEOM;
- i++;
+ gip = geom_lookupid(gmp, ge->lg_id);
+ gip->lg_ptr = ge;
+ gip->lg_what = ISGEOM;
LIST_FOREACH(pr, &ge->lg_provider, lg_provider) {
- gmp->lg_ident[i].lg_id = pr->lg_id;
- gmp->lg_ident[i].lg_ptr = pr;
- gmp->lg_ident[i].lg_what = ISPROVIDER;
- i++;
+ gip = geom_lookupid(gmp, pr->lg_id);
+ gip->lg_ptr = pr;
+ gip->lg_what = ISPROVIDER;
}
LIST_FOREACH(co, &ge->lg_consumer, lg_consumer) {
- gmp->lg_ident[i].lg_id = co->lg_id;
- gmp->lg_ident[i].lg_ptr = co;
- gmp->lg_ident[i].lg_what = ISCONSUMER;
- i++;
+ gip = geom_lookupid(gmp, co->lg_id);
+ gip->lg_ptr = co;
+ gip->lg_what = ISCONSUMER;
}
}
}
@@ -449,7 +498,10 @@ geom_deletetree(struct gmesh *gmp)
struct ggeom *ge;
struct gprovider *pr;
struct gconsumer *co;
+ unsigned i;
+ for (i = 0; gmp->lg_ident[i].lg_id != NULL; i++)
+ free(gmp->lg_ident[i].lg_id);
free(gmp->lg_ident);
gmp->lg_ident = NULL;
for (;;) {
diff --git a/lib/libgeom/libgeom.h b/lib/libgeom/libgeom.h
index c951f25..5a38021 100644
--- a/lib/libgeom/libgeom.h
+++ b/lib/libgeom/libgeom.h
@@ -71,7 +71,8 @@ struct gident {
enum { ISCLASS,
ISGEOM,
ISPROVIDER,
- ISCONSUMER } lg_what;
+ ISCONSUMER,
+ ISUNRESOLVED } lg_what;
};
struct gmesh {
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