wdctl: default to /dev/watchdog0

Let's use miscdev /dev/watchdog as fallback only. We need (if possible)
cdev /dev/watchdog0 as this device has entry in /sys/class/watchdog.

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/include/pathnames.h b/include/pathnames.h
index ee470ee4b0dbb8ac3512322db45835ee7a586f1b..6f091d5f061cac302a10bd28eadc8ded150e65d6 100644 (file)
--- a/include/pathnames.h
+++ b/include/pathnames.h
@@ -167,9 +167,6 @@
 /* deprecated */
 #define _PATH_RAWDEVCTL_OLD    "/dev/rawctl"
 
-/* wdctl path */
-#define _PATH_WATCHDOG_DEV     "/dev/watchdog"
-
 /* ipc paths */
 #define _PATH_PROC_SYSV_MSG    "/proc/sysvipc/msg"
 #define _PATH_PROC_SYSV_SEM    "/proc/sysvipc/sem"

diff --git a/sys-utils/wdctl.c b/sys-utils/wdctl.c
index b4f2c6b56e75db9ddaca6517a3a0f9b293e8d8b1..772e6b9685d1e389cc3227627075d78124879461 100644 (file)
--- a/sys-utils/wdctl.c
+++ b/sys-utils/wdctl.c
@@ -105,7 +105,7 @@ static int columns[ARRAY_SIZE(infos) * 2];
 static int ncolumns;
 
 struct wd_device {
-       char            *devpath;
+       const char      *devpath;
 
        int             timeout;
        int             timeleft;
@@ -170,10 +170,32 @@ static struct colinfo *get_column_info(unsigned num)
        return &infos[ get_column_id(num) ];
 }
 
+/* We preffer cdev /dev/watchdog0 as this device has node in
+ * /sys/class/watchdog/. The old miscdev /dev/watchdog is fallback for old
+ * systemds only.
+ */
+static const char *get_default_device(void)
+{
+       const char **p;
+       static const char *devs[] = {
+               "/dev/watchdog0",
+               "/dev/watchdog",
+               NULL
+       };
+
+       for (p = devs; *p; p++) {
+               if (access(*p, F_OK) == 0)
+                       return *p;
+       }
+
+       return NULL;
+}
+
 static void __attribute__((__noreturn__)) usage(void)
 {
        FILE *out = stdout;
        size_t i;
+       const char *dflt = get_default_device();
 
        fputs(USAGE_HEADER, out);
        fprintf(out,
@@ -198,7 +220,10 @@ static void __attribute__((__noreturn__)) usage(void)
        printf(USAGE_HELP_OPTIONS(24));
        fputs(USAGE_SEPARATOR, out);
 
-       fprintf(out, _("The default device is %s.\n"), _PATH_WATCHDOG_DEV);
+       if (dflt)
+               fprintf(out, _("The default device is %s.\n"), dflt);
+       else
+               fprintf(out, _("No default device is available.\n"));
 
        fputs(USAGE_COLUMNS, out);
        for (i = 0; i < ARRAY_SIZE(infos); i++)
@@ -507,6 +532,7 @@ int main(int argc, char *argv[])
        int c, res = EXIT_SUCCESS, count = 0;
        uint32_t wanted = 0;
        int timeout = 0;
+       const char *dflt_device = NULL;
 
        static const struct option long_opts[] = {
                { "flags",      required_argument, NULL, 'f' },
@@ -595,15 +621,18 @@ int main(int argc, char *argv[])
                columns[ncolumns++] = COL_BSTATUS;
        }
 
+       /* Device no specified, use default. */
+       if (optind == argc) {
+               dflt_device = get_default_device();
+               if (!dflt_device)
+                       err(EXIT_FAILURE, _("No default device is available."));
+       }
+
        do {
                int rc;
 
                memset(&wd, 0, sizeof(wd));
-
-               if (optind == argc)
-                       wd.devpath = _PATH_WATCHDOG_DEV;
-               else
-                       wd.devpath = argv[optind++];
+               wd.devpath = dflt_device ? dflt_device : argv[optind++];
 
                if (count)
                        fputc('\n', stdout);