[Qemu-devel] [PATCH] Fix error checking and cleaning in path.c

[Jean-Christophe DUBOIS]

Very little error checking was done in path.c and we were
leaking some memories in case of error.

Signed-off-by: Jean-Christophe Dubois <address@hidden>
---
 path.c |   76 +++++++++++++++++++++++++++++++++++++++++++++++++++++----------
 1 files changed, 64 insertions(+), 12 deletions(-)

diff --git a/path.c b/path.c
index cc9e007..24e8fdd 100644
--- a/path.c
+++ b/path.c
@@ -40,15 +40,50 @@ static int strneq(const char *s1, unsigned int n, const 
char *s2)
 
 static struct pathelem *add_entry(struct pathelem *root, const char *name);
 
+static void free_entry(struct pathelem *ptr)
+{
+    if(ptr)
+    {
+        while(ptr->num_entries) {
+            if (ptr->entries[ptr->num_entries -1]) {
+                free_entry(ptr->entries[ptr->num_entries -1]);
+                qemu_free(ptr->entries[ptr->num_entries -1]);
+                ptr->entries[ptr->num_entries -1] = NULL;
+            }
+            ptr->num_entries--;
+        }
+
+        if (ptr->name) {
+            qemu_free(ptr->name);
+            ptr->name = NULL;
+        }
+
+        if (ptr->pathname) {
+            free(ptr->pathname);
+            ptr->pathname = NULL;
+        }
+    }
+}
+
 static struct pathelem *new_entry(const char *root,
                                   struct pathelem *parent,
                                   const char *name)
 {
-    struct pathelem *new = malloc(sizeof(*new));
-    new->name = strdup(name);
-    asprintf(&new->pathname, "%s/%s", root, name);
-    new->num_entries = 0;
+    struct pathelem *new = qemu_mallocz(sizeof(*new));
+
+    if (new) {
+        if (!(new->name = qemu_strdup(name)))
+            goto fail; 
+        if (asprintf(&new->pathname, "%s/%s", root, name) < 0)
+            goto fail; 
+        new->num_entries = 0;
+    }
     return new;
+
+fail:
+    free_entry(new);
+    qemu_free(new);
+    return NULL;
 }
 
 #define streq(a,b) (strcmp((a), (b)) == 0)
@@ -57,7 +92,7 @@ static struct pathelem *add_dir_maybe(struct pathelem *path)
 {
     DIR *dir;
 
-    if ((dir = opendir(path->pathname)) != NULL) {
+    if (path && ((dir = opendir(path->pathname)) != NULL)) {
         struct dirent *dirent;
 
         while ((dirent = readdir(dir)) != NULL) {
@@ -67,6 +102,7 @@ static struct pathelem *add_dir_maybe(struct pathelem *path)
         }
         closedir(dir);
     }
+
     return path;
 }
 
@@ -74,13 +110,25 @@ static struct pathelem *add_entry(struct pathelem *root, 
const char *name)
 {
     root->num_entries++;
 
-    root = realloc(root, sizeof(*root)
+    root = qemu_realloc(root, sizeof(*root)
                    + sizeof(root->entries[0])*root->num_entries);
 
-    root->entries[root->num_entries-1] = new_entry(root->pathname, root, name);
-    root->entries[root->num_entries-1]
-        = add_dir_maybe(root->entries[root->num_entries-1]);
+    if (root) {
+        root->entries[root->num_entries-1]
+            = add_dir_maybe(new_entry(root->pathname, root, name));
+
+        if (!root->entries[root->num_entries-1])
+            goto fail;
+    } else {
+        /* if realloc failed, we have leaked some memory and we can't recover 
it */
+    }
+
     return root;
+
+fail:
+    free_entry(root);
+    qemu_free(root);
+    return NULL;
 }
 
 /* This needs to be done after tree is stabilized (ie. no more reallocs!). */
@@ -140,10 +188,14 @@ void init_paths(const char *prefix)
     } else
         pstrcpy(pref_buf, sizeof(pref_buf), prefix + 1);
 
-    base = new_entry("", NULL, pref_buf);
-    base = add_dir_maybe(base);
+    base = add_dir_maybe(new_entry("", NULL, pref_buf));
+
+    if (!base)
+        abort();
+
     if (base->num_entries == 0) {
-        free (base);
+        free_entry(base);
+        qemu_free (base);
         base = NULL;
     } else {
         set_parents(base, base);
-- 
1.6.0.4