oslib: do not call g_strdup from qemu_get_exec_dir

Just return the directory without requiring the caller to free it.
This also removes a bogus check for NULL in os_find_datadir and
module_load_one; g_strdup of a static variable cannot return NULL.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/qemu/osdep.h

@@ -597,12 +597,8 @@ char *qemu_get_local_state_pathname(const char *relative_pathname);
  * Try OS specific API first, if not working, parse from argv0. */
 void qemu_init_exec_dir(const char *argv0);
 
-/* Get the saved exec dir.
- *
- * The caller is responsible for releasing the value returned with g_free()
- * after use.
- */
-char *qemu_get_exec_dir(void);
+/* Get the saved exec dir.  */
+const char *qemu_get_exec_dir(void);
 
 /**
  * qemu_getauxval:

os-posix.c

@@ -90,13 +90,9 @@ void os_setup_signal_handling(void)
  */
 char *os_find_datadir(void)
 {
-    g_autofree char *exec_dir = NULL;
     g_autofree char *dir = NULL;
 
-    exec_dir = qemu_get_exec_dir();
-    g_return_val_if_fail(exec_dir != NULL, NULL);
-
-    dir = g_build_filename(exec_dir, "pc-bios", NULL);
+    dir = g_build_filename(qemu_get_exec_dir(), "pc-bios", NULL);
     if (g_file_test(dir, G_FILE_TEST_IS_DIR)) {
         return g_steal_pointer(&dir);
     }

os-win32.c

@@ -65,7 +65,7 @@ void os_setup_early_signal_handling(void)
  */
 char *os_find_datadir(void)
 {
-    return qemu_get_exec_dir();
+    return g_strdup(qemu_get_exec_dir());
 }
 
 void os_set_line_buffering(void)

tests/qtest/fuzz/fuzz.c

@@ -143,7 +143,8 @@ int LLVMFuzzerInitialize(int *argc, char ***argv, char ***envp)
 {
 
     char *target_name;
-    char *bindir, *datadir;
+    const char *bindir;
+    char *datadir;
     bool serialize = false;
 
     /* Initialize qgraph and modules */
@@ -166,7 +167,6 @@ int LLVMFuzzerInitialize(int *argc, char ***argv, char ***envp)
          */
         bindir = g_path_get_dirname(**argv);
         datadir = g_build_filename(bindir, "pc-bios", NULL);
-        g_free(bindir);
         if (g_file_test(datadir, G_FILE_TEST_IS_DIR)) {
             qemu_add_data_dir(datadir);
         }

util/module.c

@@ -172,7 +172,6 @@ bool module_load_one(const char *prefix, const char *lib_name)
 
 #ifdef CONFIG_MODULES
     char *fname = NULL;
-    char *exec_dir;
 #ifdef CONFIG_MODULE_UPGRADES
     char *version_dir;
 #endif
@@ -199,13 +198,12 @@ bool module_load_one(const char *prefix, const char *lib_name)
         return true;
     }
 
-    exec_dir = qemu_get_exec_dir();
     search_dir = getenv("QEMU_MODULE_DIR");
     if (search_dir != NULL) {
         dirs[n_dirs++] = g_strdup_printf("%s", search_dir);
     }
     dirs[n_dirs++] = g_strdup_printf("%s", CONFIG_QEMU_MODDIR);
-    dirs[n_dirs++] = g_strdup_printf("%s", exec_dir ? : "");
+    dirs[n_dirs++] = g_strdup(qemu_get_exec_dir());
 
 #ifdef CONFIG_MODULE_UPGRADES
     version_dir = g_strcanon(g_strdup(QEMU_PKGVERSION),
@@ -216,9 +214,6 @@ bool module_load_one(const char *prefix, const char *lib_name)
 
     assert(n_dirs <= ARRAY_SIZE(dirs));
 
-    g_free(exec_dir);
-    exec_dir = NULL;
-
     for (i = 0; i < n_dirs; i++) {
         fname = g_strdup_printf("%s/%s%s",
                 dirs[i], module_name, CONFIG_HOST_DSOSUF);

util/oslib-posix.c

@@ -366,7 +366,9 @@ void qemu_init_exec_dir(const char *argv0)
     char *p = NULL;
     char buf[PATH_MAX];
 
-    assert(!exec_dir[0]);
+    if (exec_dir[0]) {
+        return;
+    }
 
 #if defined(__linux__)
     {
@@ -439,9 +441,9 @@ void qemu_init_exec_dir(const char *argv0)
     g_free(dir);
 }
 
-char *qemu_get_exec_dir(void)
+const char *qemu_get_exec_dir(void)
 {
-    return g_strdup(exec_dir);
+    return exec_dir;
 }
 
 static void sigbus_handler(int signal)

util/oslib-win32.c

@@ -315,7 +315,7 @@ void qemu_set_tty_echo(int fd, bool echo)
     }
 }
 
-static char exec_dir[PATH_MAX];
+static char *exec_dir;
 
 void qemu_init_exec_dir(const char *argv0)
 {
@@ -324,6 +324,10 @@ void qemu_init_exec_dir(const char *argv0)
     char buf[MAX_PATH];
     DWORD len;
 
+    if (exec_dir) {
+        return;
+    }
+
     len = GetModuleFileName(NULL, buf, sizeof(buf) - 1);
     if (len == 0) {
         return;
@@ -336,13 +340,13 @@ void qemu_init_exec_dir(const char *argv0)
     }
     *p = 0;
     if (access(buf, R_OK) == 0) {
-        pstrcpy(exec_dir, sizeof(exec_dir), buf);
+        exec_dir = g_strdup(buf);
     }
 }
 
-char *qemu_get_exec_dir(void)
+const char *qemu_get_exec_dir(void)
 {
-    return g_strdup(exec_dir);
+    return exec_dir;
 }
 
 #if !GLIB_CHECK_VERSION(2, 50, 0)