1 files changed, 43 insertions, 150 deletions

diff --git a/util/path.c b/util/path.c
index 7f9fc272fb..8e174eb436 100644
--- a/util/path.c
+++ b/util/path.c
@@ -8,170 +8,63 @@
 #include <dirent.h>
 #include "qemu/cutils.h"
 #include "qemu/path.h"
+#include "qemu/thread.h"
 
-struct pathelem
-{
-    /* Name of this, eg. lib */
-    char *name;
-    /* Full path name, eg. /usr/gnemul/x86-linux/lib. */
-    char *pathname;
-    struct pathelem *parent;
-    /* Children */
-    unsigned int num_entries;
-    struct pathelem *entries[0];
-};
-
-static struct pathelem *base;
-
-/* First N chars of S1 match S2, and S2 is N chars long. */
-static int strneq(const char *s1, unsigned int n, const char *s2)
-{
-    unsigned int i;
-
-    for (i = 0; i < n; i++)
-        if (s1[i] != s2[i])
-            return 0;
-    return s2[i] == 0;
-}
-
-static struct pathelem *add_entry(struct pathelem *root, const char *name,
-                                  unsigned type);
+static const char *base;
+static GHashTable *hash;
+static QemuMutex lock;
 
-static struct pathelem *new_entry(const char *root,
-                                  struct pathelem *parent,
-                                  const char *name)
-{
-    struct pathelem *new = g_malloc(sizeof(*new));
-    new->name = g_strdup(name);
-    new->pathname = g_strdup_printf("%s/%s", root, name);
-    new->num_entries = 0;
-    return new;
-}
-
-#define streq(a,b) (strcmp((a), (b)) == 0)
-
-/* Not all systems provide this feature */
-#if defined(DT_DIR) && defined(DT_UNKNOWN) && defined(DT_LNK)
-# define dirent_type(dirent) ((dirent)->d_type)
-# define is_dir_maybe(type) \
-    ((type) == DT_DIR || (type) == DT_UNKNOWN || (type) == DT_LNK)
-#else
-# define dirent_type(dirent) (1)
-# define is_dir_maybe(type)  (type)
-#endif
-
-static struct pathelem *add_dir_maybe(struct pathelem *path)
+void init_paths(const char *prefix)
 {
-    DIR *dir;
-
-    if ((dir = opendir(path->pathname)) != NULL) {
-        struct dirent *dirent;
-
-        while ((dirent = readdir(dir)) != NULL) {
-            if (!streq(dirent->d_name,".") && !streq(dirent->d_name,"..")){
-                path = add_entry(path, dirent->d_name, dirent_type(dirent));
-            }
-        }
-        closedir(dir);
+    if (prefix[0] == '\0' || !strcmp(prefix, "/")) {
+        return;
     }
-    return path;
-}
-
-static struct pathelem *add_entry(struct pathelem *root, const char *name,
-                                  unsigned type)
-{
-    struct pathelem **e;
-
-    root->num_entries++;
-
-    root = g_realloc(root, sizeof(*root)
-                   + sizeof(root->entries[0])*root->num_entries);
-    e = &root->entries[root->num_entries-1];
 
-    *e = new_entry(root->pathname, root, name);
-    if (is_dir_maybe(type)) {
-        *e = add_dir_maybe(*e);
+    if (prefix[0] == '/') {
+        base = g_strdup(prefix);
+    } else {
+        char *cwd = g_get_current_dir();
+        base = g_build_filename(cwd, prefix, NULL);
+        g_free(cwd);
     }
 
-    return root;
-}
-
-/* This needs to be done after tree is stabilized (ie. no more reallocs!). */
-static void set_parents(struct pathelem *child, struct pathelem *parent)
-{
-    unsigned int i;
-
-    child->parent = parent;
-    for (i = 0; i < child->num_entries; i++)
-        set_parents(child->entries[i], child);
+    hash = g_hash_table_new(g_str_hash, g_str_equal);
+    qemu_mutex_init(&lock);
 }
 
-/* FIXME: Doesn't handle DIR/.. where DIR is not in emulated dir. */
-static const char *
-follow_path(const struct pathelem *cursor, const char *name)
-{
-    unsigned int i, namelen;
-
-    name += strspn(name, "/");
-    namelen = strcspn(name, "/");
-
-    if (namelen == 0)
-        return cursor->pathname;
-
-    if (strneq(name, namelen, ".."))
-        return follow_path(cursor->parent, name + namelen);
-
-    if (strneq(name, namelen, "."))
-        return follow_path(cursor, name + namelen);
-
-    for (i = 0; i < cursor->num_entries; i++)
-        if (strneq(name, namelen, cursor->entries[i]->name))
-            return follow_path(cursor->entries[i], name + namelen);
-
-    /* Not found */
-    return NULL;
-}
-
-void init_paths(const char *prefix)
+/* Look for path in emulation dir, otherwise return name. */
+const char *path(const char *name)
 {
-    char pref_buf[PATH_MAX];
-
-    if (prefix[0] == '\0' ||
-        !strcmp(prefix, "/"))
-        return;
+    gpointer key, value;
+    const char *ret;
 
-    if (prefix[0] != '/') {
-        char *cwd = getcwd(NULL, 0);
-        size_t pref_buf_len = sizeof(pref_buf);
+    /* Only do absolute paths: quick and dirty, but should mostly be OK.  */
+    if (!base || !name || name[0] != '/') {
+        return name;
+    }
 
-        if (!cwd)
-            abort();
-        pstrcpy(pref_buf, sizeof(pref_buf), cwd);
-        pstrcat(pref_buf, pref_buf_len, "/");
-        pstrcat(pref_buf, pref_buf_len, prefix);
-        free(cwd);
-    } else
-        pstrcpy(pref_buf, sizeof(pref_buf), prefix + 1);
+    qemu_mutex_lock(&lock);
 
-    base = new_entry("", NULL, pref_buf);
-    base = add_dir_maybe(base);
-    if (base->num_entries == 0) {
-        g_free(base->pathname);
-        g_free(base->name);
-        g_free(base);
-        base = NULL;
+    /* Have we looked up this file before?  */
+    if (g_hash_table_lookup_extended(hash, name, &key, &value)) {
+        ret = value ? value : name;
     } else {
-        set_parents(base, base);
+        char *save = g_strdup(name);
+        char *full = g_build_filename(base, name, NULL);
+
+        /* Look for the path; record the result, pass or fail.  */
+        if (access(full, F_OK) == 0) {
+            /* Exists.  */
+            g_hash_table_insert(hash, save, full);
+            ret = full;
+        } else {
+            /* Does not exist.  */
+            g_free(full);
+            g_hash_table_insert(hash, save, NULL);
+            ret = name;
+        }
     }
-}
-
-/* Look for path in emulation dir, otherwise return name. */
-const char *path(const char *name)
-{
-    /* Only do absolute paths: quick and dirty, but should mostly be OK.
-       Could do relative by tracking cwd. */
-    if (!base || !name || name[0] != '/')
-        return name;
 
-    return follow_path(base, name) ?: name;
+    qemu_mutex_unlock(&lock);
+    return ret;
 }