From: Michael Tokarev Date: Fri, 1 Aug 2025 11:53:14 +0000 (+0300) Subject: qga: correctly write to /sys/power/state on linux X-Git-Tag: v10.1.0-rc2~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b217d987a3c5c6e2473956723b396bc1ff0f5b2b;p=thirdparty%2Fqemu.git qga: correctly write to /sys/power/state on linux Commit v9.0.0-343-g2048129625 introduced usage of g_file_set_contents() function to write to /sys/power/state. This function uses G_FILE_SET_CONTENTS_CONSISTENT flag to g_file_set_contents_full(), which is implemented by creating a temp file in the same directory and renaming it to the final destination. Which is not how sysfs works. Here, there's not a big deal to do open/write/close - it becomes almost the same as using g_file_set_contents[_full](). But it does not have surprises like this. Also, since this is linux code, it should be ok to use %m in the error reporting function. Fixes: 2048129625 "qga/commands-posix: don't do fork()/exec() when suspending via sysfs" Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3057 Signed-off-by: Michael Tokarev Reviewed-by: Stefan Hajnoczi Message-ID: <20250801115316.6845-1-mjt@tls.msk.ru> Signed-off-by: Stefan Hajnoczi --- diff --git a/qga/commands-linux.c b/qga/commands-linux.c index 9e8a934b9a..9dc0c82503 100644 --- a/qga/commands-linux.c +++ b/qga/commands-linux.c @@ -1400,20 +1400,22 @@ static bool linux_sys_state_supports_mode(SuspendMode mode, Error **errp) static void linux_sys_state_suspend(SuspendMode mode, Error **errp) { - g_autoptr(GError) local_gerr = NULL; const char *sysfile_strs[3] = {"disk", "mem", NULL}; const char *sysfile_str = sysfile_strs[mode]; + int fd; if (!sysfile_str) { error_setg(errp, "unknown guest suspend mode"); return; } - if (!g_file_set_contents(LINUX_SYS_STATE_FILE, sysfile_str, - -1, &local_gerr)) { - error_setg(errp, "suspend: cannot write to '%s': %s", - LINUX_SYS_STATE_FILE, local_gerr->message); - return; + fd = open(LINUX_SYS_STATE_FILE, O_WRONLY); + if (fd < 0 || write(fd, sysfile_str, strlen(sysfile_str)) < 0) { + error_setg(errp, "suspend: cannot write to '%s': %m", + LINUX_SYS_STATE_FILE); + } + if (fd >= 0) { + close(fd); } }