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[PATCH v4 1/7] util: Introduce qemu_get_runtime_dir()
From: |
Akihiko Odaki |
Subject: |
[PATCH v4 1/7] util: Introduce qemu_get_runtime_dir() |
Date: |
Tue, 16 Jul 2024 16:27:31 +0900 |
qemu_get_runtime_dir() returns a dynamically allocated directory path
that is appropriate for storing runtime files. It corresponds to "run"
directory in Unix.
With a tree-wide search, it was found that there are several cases
where such a functionality is implemented so let's have one as a common
utlity function.
A notable feature of qemu_get_runtime_dir() is that it uses
$XDG_RUNTIME_DIR if available. While the function is often called by
executables which requires root privileges, it is still possible that
they are called from a user without privilege to write the system
runtime directory. In fact, I decided to write this patch when I ran
virtiofsd in a Linux namespace created by a normal user and realized
it tries to write the system runtime directory, not writable in this
case. $XDG_RUNTIME_DIR should provide a writable directory in such
cases.
This function does not use qemu_get_local_state_dir() or its logic
for Windows. Actually the implementation of qemu_get_local_state_dir()
for Windows seems not right as it calls g_get_system_data_dirs(),
which refers to $XDG_DATA_DIRS. In Unix terminology, it is basically
"/usr/share", not "/var", which qemu_get_local_state_dir() is intended
to provide. Instead, this function try to use the following in order:
- $XDG_RUNTIME_DIR
- LocalAppData folder
- get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run")
This function does not use g_get_user_runtime_dir() either as it
falls back to g_get_user_cache_dir() when $XDG_DATA_DIRS is not
available. In the case, we rather use:
get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run")
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20230921075425.16738-2-akihiko.odaki@daynix.com>
---
include/qemu/osdep.h | 12 ++++++++++++
util/oslib-posix.c | 11 +++++++++++
util/oslib-win32.c | 26 ++++++++++++++++++++++++++
3 files changed, 49 insertions(+)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 191916f38e6d..fe8609fc1375 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -670,6 +670,18 @@ void qemu_set_cloexec(int fd);
*/
char *qemu_get_local_state_dir(void);
+/**
+ * qemu_get_runtime_dir:
+ *
+ * Return a dynamically allocated directory path that is appropriate for
storing
+ * runtime files. It corresponds to "run" directory in Unix, and uses
+ * $XDG_RUNTIME_DIR if available.
+ *
+ * The caller is responsible for releasing the value returned with g_free()
+ * after use.
+ */
+char *qemu_get_runtime_dir(void);
+
/**
* qemu_getauxval:
* @type: the auxiliary vector key to lookup
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index e76441695bdc..9599509a9aa7 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -278,6 +278,17 @@ qemu_get_local_state_dir(void)
return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR);
}
+char *
+qemu_get_runtime_dir(void)
+{
+ char *env = getenv("XDG_RUNTIME_DIR");
+ if (env) {
+ return g_strdup(env);
+ }
+
+ return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run");
+}
+
void qemu_set_tty_echo(int fd, bool echo)
{
struct termios tty;
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index b623830d624f..8c5a02ee881d 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -27,6 +27,8 @@
*/
#include "qemu/osdep.h"
+#include <shlobj.h>
+#include <wchar.h>
#include <windows.h>
#include "qapi/error.h"
#include "qemu/main-loop.h"
@@ -237,6 +239,30 @@ qemu_get_local_state_dir(void)
return g_strdup(data_dirs[0]);
}
+char *
+qemu_get_runtime_dir(void)
+{
+ size_t size = GetEnvironmentVariableA("XDG_RUNTIME_DIR", NULL, 0);
+ if (size) {
+ char *env = g_malloc(size);
+ GetEnvironmentVariableA("XDG_RUNTIME_DIR", env, size);
+ return env;
+ }
+
+ PWSTR wpath;
+ const wchar_t *cwpath;
+ if (!SHGetKnownFolderPath(&FOLDERID_LocalAppData, KF_FLAG_DEFAULT, NULL,
&wpath)) {
+ cwpath = wpath;
+ size = wcsrtombs(NULL, &cwpath, 0, &(mbstate_t){0}) + 1;
+ char *path = g_malloc(size);
+ wcsrtombs(path, &cwpath, size, &(mbstate_t){0});
+ CoTaskMemFree(wpath);
+ return path;
+ }
+
+ return get_relocated_path(CONFIG_QEMU_LOCALSTATEDIR "/run");
+}
+
void qemu_set_tty_echo(int fd, bool echo)
{
HANDLE handle = (HANDLE)_get_osfhandle(fd);
--
2.45.2
[PATCH v4 2/7] ivshmem-server: Use qemu_get_runtime_dir(), Akihiko Odaki, 2024/07/16
[PATCH v4 4/7] scsi: Use qemu_get_runtime_dir(), Akihiko Odaki, 2024/07/16
[PATCH v4 5/7] module: Use qemu_get_runtime_dir(), Akihiko Odaki, 2024/07/16
[PATCH v4 3/7] qga: Use qemu_get_runtime_dir(), Akihiko Odaki, 2024/07/16
[PATCH v4 6/7] util: Remove qemu_get_local_state_dir(), Akihiko Odaki, 2024/07/16
[PATCH v4 7/7] spice-app: Use qemu_get_runtime_dir(), Akihiko Odaki, 2024/07/16