hwclock: add debugging to open_rtc()

Earlier when open_rtc() returned -1 the char *rtc_dev_name end up having
NULL that made it unsuitable to be used in error message.  Now one can debug
what paths the open_rtc() tries to use when one has to debug why 'cannot
open rtc device' happen.

Reviewed-by: J William Piggott <elseifthen@gmx.com>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/sys-utils/hwclock-rtc.c b/sys-utils/hwclock-rtc.c
index 48a6f4d586d15601118601162952ae1d04fa3371..5e11aeebd32cdbabd5c2a1ed3914c1656a656470 100644 (file)
--- a/sys-utils/hwclock-rtc.c
+++ b/sys-utils/hwclock-rtc.c
@@ -92,7 +92,7 @@ struct linux_rtc_time {
  */
 
 /* default or user defined dev (by hwclock --rtc=<path>) */
-static char *rtc_dev_name;
+static const char *rtc_dev_name;
 static int rtc_dev_fd = -1;
 
 static void close_rtc(void)
@@ -104,17 +104,16 @@ static void close_rtc(void)
 
 static int open_rtc(const struct hwclock_control *ctl)
 {
-       char *fls[] = {
+       static const char *fls[] = {
 #ifdef __ia64__
                "/dev/efirtc",
                "/dev/misc/efirtc",
 #endif
                "/dev/rtc",
                "/dev/rtc0",
-               "/dev/misc/rtc",
-               NULL
+               "/dev/misc/rtc"
        };
-       char **p;
+       size_t i;
 
        if (rtc_dev_fd != -1)
                return rtc_dev_fd;
@@ -124,19 +123,20 @@ static int open_rtc(const struct hwclock_control *ctl)
                rtc_dev_name = ctl->rtc_dev_name;
                rtc_dev_fd = open(rtc_dev_name, O_RDONLY);
        } else {
-               for (p = fls; *p; ++p) {
-                       rtc_dev_fd = open(*p, O_RDONLY);
+               for (i = 0; i < ARRAY_SIZE(fls); i++) {
+                       if (ctl->debug)
+                               printf(_("Trying to open: %s\n"), fls[i]);
+                       rtc_dev_fd = open(fls[i], O_RDONLY);
 
                        if (rtc_dev_fd < 0
                            && (errno == ENOENT || errno == ENODEV))
                                continue;
-                       rtc_dev_name = *p;
+                       rtc_dev_name = fls[i];
                        break;
                }
                if (rtc_dev_fd < 0)
                        rtc_dev_name = *fls;    /* default for error messages */
        }
-
        if (rtc_dev_fd != 1)
                atexit(close_rtc);
        return rtc_dev_fd;
@@ -147,7 +147,7 @@ static int open_rtc_or_exit(const struct hwclock_control *ctl)
        int rtc_fd = open_rtc(ctl);
 
        if (rtc_fd < 0) {
-               warn(_("cannot open %s"), rtc_dev_name);
+               warn(_("cannot open rtc device"));
                hwclock_exit(ctl, EX_OSFILE);
        }
        return rtc_fd;
@@ -242,7 +242,7 @@ static int synchronize_to_clock_tick_rtc(const struct hwclock_control *ctl)
 
        rtc_fd = open_rtc(ctl);
        if (rtc_fd == -1) {
-               warn(_("cannot open %s"), rtc_dev_name);
+               warn(_("cannot open rtc device"));
                ret = 1;
        } else {
                int rc;         /* Return code from ioctl */
@@ -389,7 +389,7 @@ struct clock_ops *probe_for_rtc_clock(const struct hwclock_control *ctl)
        if (rtc_fd >= 0)
                return &rtc;
        if (ctl->debug)
-               warn(_("cannot open %s"), ctl->rtc_dev_name);
+               warn(_("cannot open rtc device"));
        return NULL;
 }
 
@@ -408,10 +408,9 @@ int get_epoch_rtc(const struct hwclock_control *ctl, unsigned long *epoch_p,
                                warnx(_
                                      ("To manipulate the epoch value in the kernel, we must "
                                       "access the Linux 'rtc' device driver via the device special "
-                                      "file %s.  This file does not exist on this system."),
-                                     rtc_dev_name);
+                                      "file.  This file does not exist on this system."));
                        else
-                               warn(_("cannot open %s"), rtc_dev_name);
+                               warn(_("cannot open rtc device"));
                }
                return 1;
        }
@@ -455,10 +454,9 @@ int set_epoch_rtc(const struct hwclock_control *ctl)
                        warnx(_
                              ("To manipulate the epoch value in the kernel, we must "
                               "access the Linux 'rtc' device driver via the device special "
-                              "file %s.  This file does not exist on this system."),
-                             rtc_dev_name);
+                              "file.  This file does not exist on this system."));
                else
-                       warn(_("cannot open %s"), ctl->rtc_dev_name);
+                       warn(_("cannot open rtc device"));
                return 1;
        }