rtcwake: do not overwrite device name

This improves error messaging, and removes a memory leak.

Reviewed-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/sys-utils/rtcwake.c b/sys-utils/rtcwake.c
index 31c1eee6e7b2657a7bd0c6af5a00aea6e066c2a8..4b9483cc5b34d5b77624f1b9f496efb93b41d80b 100644 (file)
--- a/sys-utils/rtcwake.c
+++ b/sys-utils/rtcwake.c
@@ -49,7 +49,7 @@
 
 #define ADJTIME_ZONE_STRLEN    8
 
-#define RTC_PATH               "/sys/class/rtc/%s/device/power/wakeup"
+#define SYS_WAKEUP_PATH_TEMPLATE       "/sys/class/rtc/%s/device/power/wakeup"
 #define SYS_POWER_STATE_PATH   "/sys/power/state"
 #define DEFAULT_DEVICE         "/dev/rtc0"
 
@@ -136,9 +136,11 @@ static int is_wakeup_enabled(const char *devname)
 {
        char    buf[128], *s;
        FILE    *f;
+       size_t  skip = 0;
 
-       /* strip the '/dev/' from the devname here */
-       snprintf(buf, sizeof buf, RTC_PATH, devname + strlen("/dev/"));
+       if (startswith(devname, "/dev/"))
+               skip = 5;
+       snprintf(buf, sizeof buf, SYS_WAKEUP_PATH_TEMPLATE, devname + skip);
        f = fopen(buf, "r");
        if (!f) {
                warn(_("cannot open %s"), buf);
@@ -377,6 +379,22 @@ static int get_mode(const char *optarg)
        return -EINVAL;
 }
 
+static int open_dev_rtc(const char *devname)
+{
+       int fd;
+       char *devpath = NULL;
+
+       if (startswith(devname, "/dev"))
+               devpath = xstrdup(devname);
+       else
+               xasprintf(&devpath, "/dev/%s", devname);
+       fd = open(devpath, O_RDONLY | O_CLOEXEC);
+       if (fd < 0)
+               err(EXIT_FAILURE, _("%s: unable to find device"), devpath);
+       free(devpath);
+       return fd;
+}
+
 int main(int argc, char **argv)
 {
        struct rtcwake_control ctl = {
@@ -503,29 +521,12 @@ int main(int argc, char **argv)
                usage(stderr);
        }
 
-       /* when devname doesn't start with /dev, append it */
-       if (strncmp(devname, "/dev/", strlen("/dev/")) != 0) {
-               char *new_devname;
-
-               new_devname = xmalloc(strlen(devname) + strlen("/dev/") + 1);
-
-               strcpy(new_devname, "/dev/");
-               strcat(new_devname, devname);
-               devname = new_devname;
-       }
+       /* device must exist and (if we'll sleep) be wakeup-enabled */
+       fd = open_dev_rtc(devname);
 
        if (suspend != ON_MODE && suspend != NO_MODE && !is_wakeup_enabled(devname))
                errx(EXIT_FAILURE, _("%s not enabled for wakeup events"), devname);
 
-       /* this RTC must exist and (if we'll sleep) be wakeup-enabled */
-#ifdef O_CLOEXEC
-       fd = open(devname, O_RDONLY | O_CLOEXEC);
-#else
-       fd = open(devname, O_RDONLY);
-#endif
-       if (fd < 0)
-               err(EXIT_FAILURE, _("cannot open %s"), devname);
-
        /* relative or absolute alarm time, normalized to time_t */
        if (get_basetimes(&ctl, fd) < 0)
                exit(EXIT_FAILURE);