dmesg: inform user when klogctl() or read_buffer() fails

Fix to small regression which made 'dmesg --clear' not to error
when running without root privileges.  Same happen with '-D' and
few other options as well.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index c4d1f9f38e15c8254596d5662692ab6ec1755f44..a3d95f1b77773f3670d942b37df8587637a66ed7 100644 (file)
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -985,7 +985,7 @@ static int read_kmsg(struct dmesg_control *ctl)
 int main(int argc, char *argv[])
 {
        char *buf = NULL;
-       ssize_t  n;
+       ssize_t  n, r;
        int  c;
        int  console_level = 0;
        static struct dmesg_control ctl = {
@@ -1128,6 +1128,7 @@ int main(int argc, char *argv[])
        argc -= optind;
        argv += optind;
        n = 0;
+       r = 0;
 
        if (argc > 1)
                usage(stderr);
@@ -1148,9 +1149,9 @@ int main(int argc, char *argv[])
                if (ctl.method == DMESG_METHOD_KMSG && init_kmsg(&ctl) != 0)
                        ctl.method = DMESG_METHOD_SYSLOG;
 
-               n = read_buffer(&ctl, &buf);
-               if (n > 0)
-                       print_buffer(&ctl, buf, n);
+               r = read_buffer(&ctl, &buf);
+               if (r > 0)
+                       print_buffer(&ctl, buf, r);
                if (!ctl.mmap_buff)
                        free(buf);
                break;
@@ -1170,8 +1171,10 @@ int main(int argc, char *argv[])
        if (ctl.kmsg >= 0)
                close(ctl.kmsg);
 
-       if (n < 0 && ctl.method == DMESG_METHOD_SYSLOG)
+       if (n < 0)
                err(EXIT_FAILURE, _("klogctl failed"));
+       if (r < 0)
+               err(EXIT_FAILURE, _("read_buffer failed"));
 
        return EXIT_SUCCESS;
 }