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") V2 -> V3: Rebase to the current master. Dropped patch "qga: Remove platform GUID definitions" since it is irrelevant. V1 -> V2: Rebased to the current master since Patchew complains. Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com> --- Changes in v4: - Rebased. - Link to v3: https://lore.kernel.org/r/20230921075425.16738-1-akihiko.od...@daynix.com --- Akihiko Odaki (7): util: Introduce qemu_get_runtime_dir() ivshmem-server: Use qemu_get_runtime_dir() qga: Use qemu_get_runtime_dir() scsi: Use qemu_get_runtime_dir() module: Use qemu_get_runtime_dir() util: Remove qemu_get_local_state_dir() spice-app: Use qemu_get_runtime_dir() include/qemu/osdep.h | 10 +++++++--- contrib/ivshmem-server/main.c | 20 ++++++++++++++++---- qga/main.c | 9 ++++----- scsi/qemu-pr-helper.c | 6 +++--- ui/spice-app.c | 4 ++-- util/module.c | 3 ++- util/oslib-posix.c | 9 +++++++-- util/oslib-win32.c | 24 ++++++++++++++++++++---- 8 files changed, 61 insertions(+), 24 deletions(-) --- base-commit: f2cb4026fccfe073f84a4b440e41d3ed0c3134f6 change-id: 20240218-run-6f0d91ec7439 Best regards, -- Akihiko Odaki <akihiko.od...@daynix.com>
