dmesg: add --level=<list>

For example

	dmesg --level=err,warn

will print only error and warning messages.

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

diff --git a/sys-utils/dmesg.1 b/sys-utils/dmesg.1
index 8f61b86154541f851bd01ff267a113775f0b3ec3..9518ecb64b34664adae7e10bb0bfc933546ae03f 100644 (file)
--- a/sys-utils/dmesg.1
+++ b/sys-utils/dmesg.1
@@ -38,6 +38,12 @@ Disable printing messages to the console.
 Enable printing messages to the console.
 .IP "\fB\-h, \-\-help\fP"
 Print a help text and exit.
+.IP "\fB\-l, \-\-level \fIlist\fP"
+Restrict output to defined (comma separated) list of levels. For exmaple
+.sp
+  dmesg --level=err,warn
+.sp
+will print error and warning messages only.
 .IP "\fB\-n, \-\-console-level \fIlevel\fP
 Set the
 .I level

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index baf959d89bd408b9ac2b33b9770bad3babc3c5c9..c7f5cd65f42915b53e596e1d70ea36a459ef6147 100644 (file)
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -25,6 +25,7 @@
 #include "xalloc.h"
 #include "widechar.h"
 #include "writeall.h"
+#include "bitops.h"
 
 /* Close the log.  Currently a NOP. */
 #define SYSLOG_ACTION_CLOSE          0
@@ -49,6 +50,18 @@
 /* Return size of the log buffer */
 #define SYSLOG_ACTION_SIZE_BUFFER   10
 
+#ifndef LOG_PRIMASK
+#define        LOG_PRIMASK     0x07    /* mask to extract priority part (internal) */
+                               /* extract priority */
+#define        LOG_PRI(p)      ((p) & LOG_PRIMASK)
+#endif
+
+#ifndef LOG_FACMASK
+#define        LOG_FACMASK     0x03f8  /* mask to extract facility part */
+                               /* facility of pri */
+#define        LOG_FAC(p)      (((p) & LOG_FACMASK) >> 3)
+#endif
+
 /*
  * Priority names, based on sys/syslog.h
  */
@@ -89,6 +102,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
                " -d, --console-off         disable printing messages to console\n"
                " -e, --console-on          enable printing messages to console\n"
                " -h, --help                display this help and exit\n"
+               " -l, --level=LIST          restrict output to defined levels\n"
                " -n, --console-level=LEVEL set level of messages printed to console\n"
                " -r, --raw                 print the raw message buffer\n"
                " -s, --buffer-size=SIZE    buffer size to query the kernel ring buffer\n"
@@ -139,6 +153,58 @@ static int parse_level(const char *str, size_t len)
        return -1;
 }
 
+static const char *parse_faclev(const char *str, int *fac, int *lev)
+{
+       long num;
+       char *end = NULL;
+
+       if (!str)
+               return str;
+
+       errno = 0;
+       num = strtol(str, &end, 10);
+
+       if (!errno && end && end > str) {
+               *fac = LOG_FAC(num);
+               *lev = LOG_PRI(num);
+               return end + 1;         /* skip '<' */
+       }
+
+       return str;
+}
+
+static int list_to_bitarray(const char *list,
+                           int (*name2id)(const char *name, size_t namesz),
+                           char *ary)
+{
+       const char *begin = NULL, *p;
+
+       for (p = list; p && *p; p++) {
+               const char *end = NULL;
+               int id;
+
+               if (!begin)
+                       begin = p;              /* begin of the level name */
+               if (*p == ',')
+                       end = p;                /* terminate the name */
+               if (*(p + 1) == '\0')
+                       end = p + 1;            /* end of string */
+               if (!begin || !end)
+                       continue;
+               if (end <= begin)
+                       return -1;
+
+               id = name2id(begin, end - begin);
+               if (id < 0)
+                       return id;
+               setbit(ary, id);
+               begin = NULL;
+               if (end && !*end)
+                       break;
+       }
+       return 0;
+}
+
 static int get_buffer_size()
 {
        int n = klogctl(SYSLOG_ACTION_SIZE_BUFFER, NULL, 0);
@@ -228,7 +294,7 @@ static void safe_fwrite(const char *buf, size_t size, FILE *out)
        }
 }
 
-static void print_buffer(const char *buf, size_t size, int flags)
+static void print_buffer(const char *buf, size_t size, int flags, char *levels)
 {
        int i;
        const char *begin = NULL;
@@ -243,6 +309,7 @@ static void print_buffer(const char *buf, size_t size, int flags)
 
        for (i = 0; i < size; i++) {
                const char *p = buf + i, *end = NULL;
+               int fac = 0, lev = 0;
 
                if (!begin)
                        begin = p;
@@ -257,19 +324,22 @@ static void print_buffer(const char *buf, size_t size, int flags)
                if (end <= begin)
                        continue;       /* error or empty line? */
 
-               if ((flags & DMESG_FL_LEVEL) || (flags & DMESG_FL_FACILITY)) {
-                       /* parse facility and level */
-                       ;
-               } else if (*begin == '<') {
-                       /* ignore facility and level */
-                       while (begin < end) {
-                               begin++;
-                               if (*(begin - 1) == '>')
-                                       break;
+               if (*begin == '<') {
+                       if ((flags & DMESG_FL_LEVEL) || (flags & DMESG_FL_FACILITY)) {
+                               /* parse facility and level */
+                               begin = parse_faclev(begin + 1, &fac, &lev);
+                       } else {
+                               /* ignore facility and level */
+                               while (begin < end) {
+                                       begin++;
+                                       if (*(begin - 1) == '>')
+                                               break;
+                               }
                        }
                }
 
-               if (begin < end) {
+               if (begin < end &&
+                   (!lev || !levels || isset(levels, lev))) {
                        size_t sz =  end - begin;
 
                        safe_fwrite(begin, sz, stdout);
@@ -289,6 +359,7 @@ int main(int argc, char *argv[])
        int  console_level = 0;
        int  cmd = -1;
        int  flags = 0;
+       char levels[ARRAY_SIZE(level_names) / NBBY + 1] = { 0 };
 
        static const struct option longopts[] = {
                { "clear",         no_argument,       NULL, 'C' },
@@ -296,6 +367,7 @@ int main(int argc, char *argv[])
                { "raw",           no_argument,       NULL, 'r' },
                { "buffer-size",   required_argument, NULL, 's' },
                { "console-level", required_argument, NULL, 'n' },
+               { "level",         required_argument, NULL, 'l' },
                { "console-off",   no_argument,       NULL, 'd' },
                { "console-on",    no_argument,       NULL, 'e' },
                { "version",       no_argument,       NULL, 'V' },
@@ -307,7 +379,7 @@ int main(int argc, char *argv[])
        bindtextdomain(PACKAGE, LOCALEDIR);
        textdomain(PACKAGE);
 
-       while ((c = getopt_long(argc, argv, "Ccdehrn:s:V", longopts, NULL)) != -1) {
+       while ((c = getopt_long(argc, argv, "Ccdehl:rn:s:V", longopts, NULL)) != -1) {
 
                if (cmd != -1 && strchr("Ccnde", c))
                        errx(EXIT_FAILURE, "%s %s",
@@ -331,6 +403,10 @@ int main(int argc, char *argv[])
                        cmd = SYSLOG_ACTION_CONSOLE_LEVEL;
                        console_level = parse_level(optarg, 0);
                        break;
+               case 'l':
+                       flags |= DMESG_FL_LEVEL;
+                       list_to_bitarray(optarg, parse_level, levels);
+                       break;
                case 'r':
                        flags |= DMESG_FL_RAW;
                        break;
@@ -368,7 +444,7 @@ int main(int argc, char *argv[])
                        bufsize = get_buffer_size();
                n = read_buffer(&buf, bufsize, cmd == SYSLOG_ACTION_READ_CLEAR);
                if (n > 0)
-                       print_buffer(buf, n, flags);
+                       print_buffer(buf, n, flags, levels);
                free(buf);
                break;
        case SYSLOG_ACTION_CLEAR: