- Simplify the procedure of retrieving XML-data from the kernel.

- Fix a number of potential memory leaks in libgeom related to doing realloc
  without freeing old pointer if things go wrong.
- Fix a number of places in libgeom where malloc and calloc return values
  were not checked.
- Check malloc return value and provide sufficient warning messages when XML
  parsing fails.

PR:		kern/83464
Submitted by:	Dan Lukes <dan - at - obluda.cz>
Approved by:	kib (mentor)

lib/libgeom/geom_ctl.c

@@ -45,6 +45,12 @@
 #define GCTL_TABLE 1
 #include <libgeom.h>
 
+/* 
+ * Global pointer to a string that is used to avoid an errorneous free in
+ * gctl_free.
+ */
+static char nomemmsg[] = "Could not allocate memory";
+
 void
 gctl_dump(struct gctl_req *req, FILE *f)
 {
@@ -105,11 +111,12 @@ gctl_set_error(struct gctl_req *req, const char *error, ...)
 static void
 gctl_check_alloc(struct gctl_req *req, void *ptr)
 {
+
 	if (ptr != NULL)
 		return;
-	gctl_set_error(req, "Could not allocate memory");
+	gctl_set_error(req, nomemmsg);
 	if (req->error == NULL)
-		req->error = "Could not allocate memory";
+		req->error = nomemmsg;
 }
 
 /*
@@ -134,7 +141,7 @@ gctl_new_arg(struct gctl_req *req)
 	struct gctl_req_arg *ap;
 
 	req->narg++;
-	req->arg = realloc(req->arg, sizeof *ap * req->narg);
+	req->arg = reallocf(req->arg, sizeof *ap * req->narg);
 	gctl_check_alloc(req, req->arg);
 	if (req->arg == NULL) {
 		req->narg = 0;
@@ -157,6 +164,8 @@ gctl_ro_param(struct gctl_req *req, const char *name, int len, const void* value
 		return;
 	ap->name = strdup(name);
 	gctl_check_alloc(req, ap->name);
+	if (ap->name == NULL)
+		return;
 	ap->nlen = strlen(ap->name) + 1;
 	ap->value = __DECONST(void *, value);
 	ap->flag = GCTL_PARAM_RD;
@@ -180,6 +189,8 @@ gctl_rw_param(struct gctl_req *req, const char *name, int len, void* value)
 		return;
 	ap->name = strdup(name);
 	gctl_check_alloc(req, ap->name);
+	if (ap->name == NULL)
+		return;
 	ap->nlen = strlen(ap->name) + 1;
 	ap->value = value;
 	ap->flag = GCTL_PARAM_RW;
@@ -201,12 +212,11 @@ gctl_issue(struct gctl_req *req)
 
 	req->version = GCTL_VERSION;
 	req->lerror = BUFSIZ;		/* XXX: arbitrary number */
-	req->error = malloc(req->lerror);
+	req->error = calloc(1, req->lerror);
 	if (req->error == NULL) {
 		gctl_check_alloc(req, req->error);
 		return (req->error);
 	}
-	memset(req->error, 0, req->lerror);
 	req->lerror--;
 	fd = open(_PATH_DEV PATH_GEOM_CTL, O_RDONLY);
 	if (fd < 0)
@@ -232,7 +242,7 @@ gctl_free(struct gctl_req *req)
 			free(req->arg[i].name);
 	}
 	free(req->arg);
-	if (req->error != NULL)
+	if (req->error != NULL && req->error != nomemmsg)
 		free(req->error);
 	free(req);
 }

lib/libgeom/geom_getxml.c

@@ -39,28 +39,22 @@ char *
 geom_getxml()
 {
 	char *p;
-	size_t l;
-	int i;
+	size_t l = 0;
+	int mib[3];
+	size_t sizep;
 
-	l = 1024 * 1024;	/* Start big, realloc back */
-	p = malloc(l);
-	if (p) {
-		i = sysctlbyname("kern.geom.confxml", p, &l, NULL, 0);
-		if (i == 0) {
-			p = realloc(p, strlen(p) + 1);
-			return (p);
-		}
-		free(p);
-	}
-	l = 0;
-	i = sysctlbyname("kern.geom.confxml", NULL, &l, NULL, 0);
-	if (i != 0)
+	sizep = sizeof(mib) / sizeof(*mib);
+	if (sysctlnametomib("kern.geom.confxml", mib, &sizep) != 0)
+		return (NULL);
+	if (sysctl(mib, sizep, NULL, &l, NULL, 0) != 0)
+		return (NULL);
+	l += 4096;
+	p = malloc(l);
+	if (p == NULL)
+		return (NULL);
+	if (sysctl(mib, sizep, p, &l, NULL, 0) != 0) {
+		free(p);
 		return (NULL);
-	p = malloc(l + 4096);
-	i = sysctlbyname("kern.geom.confxml", p, &l, NULL, 0);
-	if (i == 0) {
-		p = realloc(p, strlen(p) + 1);
-		return (p);
 	}
-	return (NULL);
+	return (reallocf(p, strlen(p) + 1));
 }

lib/libgeom/geom_xml2tree.c

@@ -84,6 +84,11 @@ StartElement(void *userData, const char *name, const char **attr)
 	}
 	if (!strcmp(name, "class") && mt->class == NULL) {
 		mt->class = calloc(1, sizeof *mt->class);
+		if (mt->class == NULL) {
+			warn("Cannot allocate memory during processing of '%s' "
+			    "element", name);
+			return;
+		}
 		mt->class->lg_id = id;
 		LIST_INSERT_HEAD(&mt->mesh->lg_class, mt->class, lg_class);
 		LIST_INIT(&mt->class->lg_geom);
@@ -92,6 +97,11 @@ StartElement(void *userData, const char *name, const char **attr)
 	}
 	if (!strcmp(name, "geom") && mt->geom == NULL) {
 		mt->geom = calloc(1, sizeof *mt->geom);
+		if (mt->geom == NULL) {
+			warn("Cannot allocate memory during processing of '%s' "
+			    "element", name);
+			return;
+		}
 		mt->geom->lg_id = id;
 		LIST_INSERT_HEAD(&mt->class->lg_geom, mt->geom, lg_geom);
 		LIST_INIT(&mt->geom->lg_provider);
@@ -105,6 +115,11 @@ StartElement(void *userData, const char *name, const char **attr)
 	}
 	if (!strcmp(name, "consumer") && mt->consumer == NULL) {
 		mt->consumer = calloc(1, sizeof *mt->consumer);
+		if (mt->consumer == NULL) {
+			warn("Cannot allocate memory during processing of '%s' "
+			    "element", name);
+			return;
+		}
 		mt->consumer->lg_id = id;
 		LIST_INSERT_HEAD(&mt->geom->lg_consumer, mt->consumer,
 		    lg_consumer);
@@ -121,6 +136,11 @@ StartElement(void *userData, const char *name, const char **attr)
 	}
 	if (!strcmp(name, "provider") && mt->provider == NULL) {
 		mt->provider = calloc(1, sizeof *mt->provider);
+		if (mt->provider == NULL) {
+			warn("Cannot allocate memory during processing of '%s' "
+			    "element", name);
+			return;
+		}
 		mt->provider->lg_id = id;
 		LIST_INSERT_HEAD(&mt->geom->lg_provider, mt->provider,
 		    lg_provider);
@@ -162,6 +182,11 @@ EndElement(void *userData, const char *name)
 	mt = userData;
 	sbuf_finish(mt->sbuf[mt->level]);
 	p = strdup(sbuf_data(mt->sbuf[mt->level]));
+	if (p == NULL) {
+		warn("Cannot allocate memory during processing of '%s' "
+		    "element", name);
+		return;
+	}
 	sbuf_delete(mt->sbuf[mt->level]);
 	mt->sbuf[mt->level] = NULL;
 	mt->level--;
@@ -212,8 +237,18 @@ EndElement(void *userData, const char *name)
 	}
 
 	if (mt->config != NULL) {
-		gc = calloc(sizeof *gc, 1);
+		gc = calloc(1, sizeof *gc);
+		if (gc == NULL) {
+			warn("Cannot allocate memory during processing of '%s' "
+			    "element", name);
+			return;
+		}
 		gc->lg_name = strdup(name);
+		if (gc->lg_name == NULL) {
+			warn("Cannot allocate memory during processing of '%s' "
+			    "element", name);
+			return;
+		}
 		gc->lg_val = p;
 		LIST_INSERT_HEAD(mt->config, gc, lg_config);
 		return;