dmesg; support level names (e.g. --console-level=alert)

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

diff --git a/sys-utils/dmesg.1 b/sys-utils/dmesg.1
index a593485c1a798208a59b44c7abbab93f40373fbd..8f61b86154541f851bd01ff267a113775f0b3ec3 100644 (file)
--- a/sys-utils/dmesg.1
+++ b/sys-utils/dmesg.1
@@ -41,9 +41,17 @@ Print a help text and exit.
 .IP "\fB\-n, \-\-console-level \fIlevel\fP
 Set the
 .I level
-at which logging of messages is done to the console.  For example,
+at which logging of messages is done to the console. The 
+.I level
+is a level number or abbreviation of the level name. For all supported levels see
+.B dmesg \-\-help
+output.
+.sp
+For example,
 .B \-n 1
-prevents all messages, except panic messages, from appearing on the
+or
+.B \-n alert
+prevents all messages, except emergency (panic) messages, from appearing on the
 console.  All levels of messages are still written to
 .IR /proc/kmsg ,
 so

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index fde11100fe360e71bda35d578fbdc512d6482d39..94309fd59afa1033ce7fabeef32aa814558a3fed 100644 (file)
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -16,6 +16,7 @@
 #include <getopt.h>
 #include <stdlib.h>
 #include <sys/klog.h>
+#include <sys/syslog.h>
 #include <ctype.h>
 
 #include "c.h"
@@ -46,11 +47,33 @@
 /* Return size of the log buffer */
 #define SYSLOG_ACTION_SIZE_BUFFER   10
 
+/*
+ * Priority names, based on sys/syslog.h
+ */
+struct dmesg_name {
+       const char *name;
+       const char *help;
+};
+
+static const struct dmesg_name level_names[] =
+{
+       [LOG_EMERG]   = { "emerg", N_("system is unusable") },
+       [LOG_ALERT]   = { "alert", N_("action must be taken immediately") },
+       [LOG_CRIT]    = { "crit",  N_("critical conditions") },
+       [LOG_ERR]     = { "err",   N_("error conditions") },
+       [LOG_WARNING] = { "warn",  N_("warning conditions") },
+       [LOG_NOTICE]  = { "notice",N_("normal but significant condition") },
+       [LOG_INFO]    = { "info",  N_("informational") },
+       [LOG_DEBUG]   = { "debug", N_("debug-level messages") }
+};
+
 /* dmesg flags */
 #define DMESG_FL_RAW   (1 << 1)
 
 static void __attribute__((__noreturn__)) usage(FILE *out)
 {
+       int i;
+
        fprintf(out, _(
                "\nUsage:\n"
                " %s [options]\n"), program_invocation_short_name);
@@ -67,9 +90,31 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
                " -s, --buffer-size=SIZE    buffer size to query the kernel ring buffer\n"
                " -V, --version             output version information and exit\n\n"));
 
+       fprintf(out, _("Supported log levels (priorities):\n"));
+       for (i = 0; i < ARRAY_SIZE(level_names); i++) {
+               fprintf(stderr, " <%d> %7s - %s\n", i,
+                               level_names[i].name,
+                               _(level_names[i].help));
+       }
+
+       fputc('\n', out);
+
        exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
 }
 
+static int string_to_level(const char *name)
+{
+       int i;
+
+       if (!name)
+               return -1;
+
+       for (i = 0; i < ARRAY_SIZE(level_names); i++)
+               if (strcasecmp(name, level_names[i].name) == 0)
+                       return i;
+       return -1;
+}
+
 static int get_buffer_size()
 {
        int n = klogctl(SYSLOG_ACTION_SIZE_BUFFER, NULL, 0);
@@ -177,8 +222,16 @@ int main(int argc, char *argv[])
                        break;
                case 'n':
                        cmd = SYSLOG_ACTION_CONSOLE_LEVEL;
-                       console_level = strtol_or_err(optarg,
+                       if (isdigit(*optarg)) {
+                               console_level = strtol_or_err(optarg,
                                                _("failed to parse level"));
+                       } else {
+                               console_level = string_to_level(optarg);
+                               if (console_level < 0)
+                                       errx(EXIT_FAILURE,
+                                               _("%s: unknown log level"),
+                                               optarg);
+                       }
                        break;
                case 'r':
                        flags |= DMESG_FL_RAW;