qga: move linux suspend command impls to commands-linux.c

The qmp_guest_suspend_{disk,ram,hybrid} command impls in
commands-posix.c are surrounded by '#ifdef __linux__' so should
instead live in commands-linux.c

Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Konstantin Kostiuk <kkostiuk@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20240712132459.3974109-4-berrange@redhat.com>
Signed-off-by: Konstantin Kostiuk <kkostiuk@redhat.com>

1 files changed, 265 insertions, 0 deletions

diff --git a/qga/commands-linux.c b/qga/commands-linux.c
index 78580ac39d..3fabf54882 100644
--- a/qga/commands-linux.c
+++ b/qga/commands-linux.c
@@ -286,6 +286,271 @@ int qmp_guest_fsfreeze_do_thaw(Error **errp)
 }
 #endif /* CONFIG_FSFREEZE */
 
+
+#define LINUX_SYS_STATE_FILE "/sys/power/state"
+#define SUSPEND_SUPPORTED 0
+#define SUSPEND_NOT_SUPPORTED 1
+
+typedef enum {
+    SUSPEND_MODE_DISK = 0,
+    SUSPEND_MODE_RAM = 1,
+    SUSPEND_MODE_HYBRID = 2,
+} SuspendMode;
+
+/*
+ * Executes a command in a child process using g_spawn_sync,
+ * returning an int >= 0 representing the exit status of the
+ * process.
+ *
+ * If the program wasn't found in path, returns -1.
+ *
+ * If a problem happened when creating the child process,
+ * returns -1 and errp is set.
+ */
+static int run_process_child(const char *command[], Error **errp)
+{
+    int exit_status, spawn_flag;
+    GError *g_err = NULL;
+    bool success;
+
+    spawn_flag = G_SPAWN_SEARCH_PATH | G_SPAWN_STDOUT_TO_DEV_NULL |
+                 G_SPAWN_STDERR_TO_DEV_NULL;
+
+    success =  g_spawn_sync(NULL, (char **)command, NULL, spawn_flag,
+                            NULL, NULL, NULL, NULL,
+                            &exit_status, &g_err);
+
+    if (success) {
+        return WEXITSTATUS(exit_status);
+    }
+
+    if (g_err && (g_err->code != G_SPAWN_ERROR_NOENT)) {
+        error_setg(errp, "failed to create child process, error '%s'",
+                   g_err->message);
+    }
+
+    g_error_free(g_err);
+    return -1;
+}
+
+static bool systemd_supports_mode(SuspendMode mode, Error **errp)
+{
+    const char *systemctl_args[3] = {"systemd-hibernate", "systemd-suspend",
+                                     "systemd-hybrid-sleep"};
+    const char *cmd[4] = {"systemctl", "status", systemctl_args[mode], NULL};
+    int status;
+
+    status = run_process_child(cmd, errp);
+
+    /*
+     * systemctl status uses LSB return codes so we can expect
+     * status > 0 and be ok. To assert if the guest has support
+     * for the selected suspend mode, status should be < 4. 4 is
+     * the code for unknown service status, the return value when
+     * the service does not exist. A common value is status = 3
+     * (program is not running).
+     */
+    if (status > 0 && status < 4) {
+        return true;
+    }
+
+    return false;
+}
+
+static void systemd_suspend(SuspendMode mode, Error **errp)
+{
+    Error *local_err = NULL;
+    const char *systemctl_args[3] = {"hibernate", "suspend", "hybrid-sleep"};
+    const char *cmd[3] = {"systemctl", systemctl_args[mode], NULL};
+    int status;
+
+    status = run_process_child(cmd, &local_err);
+
+    if (status == 0) {
+        return;
+    }
+
+    if ((status == -1) && !local_err) {
+        error_setg(errp, "the helper program 'systemctl %s' was not found",
+                   systemctl_args[mode]);
+        return;
+    }
+
+    if (local_err) {
+        error_propagate(errp, local_err);
+    } else {
+        error_setg(errp, "the helper program 'systemctl %s' returned an "
+                   "unexpected exit status code (%d)",
+                   systemctl_args[mode], status);
+    }
+}
+
+static bool pmutils_supports_mode(SuspendMode mode, Error **errp)
+{
+    Error *local_err = NULL;
+    const char *pmutils_args[3] = {"--hibernate", "--suspend",
+                                   "--suspend-hybrid"};
+    const char *cmd[3] = {"pm-is-supported", pmutils_args[mode], NULL};
+    int status;
+
+    status = run_process_child(cmd, &local_err);
+
+    if (status == SUSPEND_SUPPORTED) {
+        return true;
+    }
+
+    if ((status == -1) && !local_err) {
+        return false;
+    }
+
+    if (local_err) {
+        error_propagate(errp, local_err);
+    } else {
+        error_setg(errp,
+                   "the helper program '%s' returned an unexpected exit"
+                   " status code (%d)", "pm-is-supported", status);
+    }
+
+    return false;
+}
+
+static void pmutils_suspend(SuspendMode mode, Error **errp)
+{
+    Error *local_err = NULL;
+    const char *pmutils_binaries[3] = {"pm-hibernate", "pm-suspend",
+                                       "pm-suspend-hybrid"};
+    const char *cmd[2] = {pmutils_binaries[mode], NULL};
+    int status;
+
+    status = run_process_child(cmd, &local_err);
+
+    if (status == 0) {
+        return;
+    }
+
+    if ((status == -1) && !local_err) {
+        error_setg(errp, "the helper program '%s' was not found",
+                   pmutils_binaries[mode]);
+        return;
+    }
+
+    if (local_err) {
+        error_propagate(errp, local_err);
+    } else {
+        error_setg(errp,
+                   "the helper program '%s' returned an unexpected exit"
+                   " status code (%d)", pmutils_binaries[mode], status);
+    }
+}
+
+static bool linux_sys_state_supports_mode(SuspendMode mode, Error **errp)
+{
+    const char *sysfile_strs[3] = {"disk", "mem", NULL};
+    const char *sysfile_str = sysfile_strs[mode];
+    char buf[32]; /* hopefully big enough */
+    int fd;
+    ssize_t ret;
+
+    if (!sysfile_str) {
+        error_setg(errp, "unknown guest suspend mode");
+        return false;
+    }
+
+    fd = open(LINUX_SYS_STATE_FILE, O_RDONLY);
+    if (fd < 0) {
+        return false;
+    }
+
+    ret = read(fd, buf, sizeof(buf) - 1);
+    close(fd);
+    if (ret <= 0) {
+        return false;
+    }
+    buf[ret] = '\0';
+
+    if (strstr(buf, sysfile_str)) {
+        return true;
+    }
+    return false;
+}
+
+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];
+
+    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;
+    }
+}
+
+static void guest_suspend(SuspendMode mode, Error **errp)
+{
+    Error *local_err = NULL;
+    bool mode_supported = false;
+
+    if (systemd_supports_mode(mode, &local_err)) {
+        mode_supported = true;
+        systemd_suspend(mode, &local_err);
+
+        if (!local_err) {
+            return;
+        }
+    }
+
+    error_free(local_err);
+    local_err = NULL;
+
+    if (pmutils_supports_mode(mode, &local_err)) {
+        mode_supported = true;
+        pmutils_suspend(mode, &local_err);
+
+        if (!local_err) {
+            return;
+        }
+    }
+
+    error_free(local_err);
+    local_err = NULL;
+
+    if (linux_sys_state_supports_mode(mode, &local_err)) {
+        mode_supported = true;
+        linux_sys_state_suspend(mode, &local_err);
+    }
+
+    if (!mode_supported) {
+        error_free(local_err);
+        error_setg(errp,
+                   "the requested suspend mode is not supported by the guest");
+    } else {
+        error_propagate(errp, local_err);
+    }
+}
+
+void qmp_guest_suspend_disk(Error **errp)
+{
+    guest_suspend(SUSPEND_MODE_DISK, errp);
+}
+
+void qmp_guest_suspend_ram(Error **errp)
+{
+    guest_suspend(SUSPEND_MODE_RAM, errp);
+}
+
+void qmp_guest_suspend_hybrid(Error **errp)
+{
+    guest_suspend(SUSPEND_MODE_HYBRID, errp);
+}
+
 /* Transfer online/offline status between @vcpu and the guest system.
  *
  * On input either @errp or *@errp must be NULL.