On Wed, 2011-02-09 at 18:46 +0100, Lawrence Rust wrote:
> This patch adds a test to rtcwake to verify that the requested suspend
> mode (standby|mem|disk) is available. If not it exits with error.
>
> This avoids the current situation where a request to suspend with an
> unsupported mode fails quietly and rtcwake returns immediately.
>
> See linux-2.6.37/Documentation/power/interface.txt
Oops, looking at the kernel code some more:
linux-2.6.37/kernel/power/main.c function state_show()
It seems that reading /sys/power/state results in a space separated list
rather than the highest state supported as I had believed. This makes
the code somewhat easier. So here's the revised form
Signed-off-by: Lawrence Rust <lawrence(at)softsystem(dot)co(dot)uk>
--- a/sys-utils/rtcwake.c 2011-01-24 10:16:34.000000000 +0100
+++ b/sys-utils/rtcwake.c 2011-02-10 09:51:52.000000000 +0100
@@ -247,6 +247,24 @@ static int setup_alarm(int fd, time_t *w
return 0;
}
+static int is_suspend_available(const char *suspend)
+{
+ int rc;
+ char buf[32];
+ FILE *f = fopen(SYS_POWER_STATE_PATH, "r");
+
+ if (!f)
+ return -1;
+
+ if (fgets(buf, sizeof buf, f) == NULL)
+ rc = -1;
+ else
+ rc = strstr(buf, suspend) != NULL;
+
+ fclose(f);
+ return rc;
+}
+
static void suspend_system(const char *suspend)
{
FILE *f = fopen(SYS_POWER_STATE_PATH, "w");
@@ -501,6 +519,11 @@ int main(int argc, char **argv)
alarm, sys_time, rtc_time, seconds);
if (strcmp(suspend, "show") && strcmp(suspend, "disable")) {
+ if (strcmp(suspend, "no") && strcmp(suspend, "on") &&
+ strcmp(suspend, "off") && is_suspend_available(suspend) <= 0) {
+ errx(EXIT_FAILURE, _("suspend to \"%s\" unavailable"), suspend);
+ }
+
/* care about alarm setup only if the show|disable
* modes are not set
*/
--
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