log: allow filtering messages with a regexp pattern

This allows printing/streaming/writing messages matching a specified
basic regular expression only.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>

diff --git a/log/logread.c b/log/logread.c
index 625540822160cbd686aaac46e4b690f7464e1682..dcf3c08a624d5d57eda56dd6f65a1cb56439dca4 100644 (file)
--- a/log/logread.c
+++ b/log/logread.c
@@ -17,6 +17,7 @@
 
 #include <fcntl.h>
 #include <time.h>
+#include <regex.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <sys/types.h>
@@ -57,7 +58,8 @@ static const struct blobmsg_policy log_policy[] = {
 
 static struct uloop_timeout retry;
 static struct uloop_fd sender;
-static const char *log_file, *log_ip, *log_port, *log_prefix, *pid_file, *hostname;
+static regex_t regexp_preg;
+static const char *log_file, *log_ip, *log_port, *log_prefix, *pid_file, *hostname, *regexp_pattern;
 static int log_type = LOG_STDOUT;
 static int log_size, log_udp, log_follow, log_trailer_null = 0;
 
@@ -128,6 +130,9 @@ static int log_notify(struct blob_attr *msg)
        }
 
        m = blobmsg_get_string(tb[LOG_MSG]);
+       if (regexp_pattern &&
+           regexec(&regexp_preg, m, 0, NULL, 0) == REG_NOMATCH)
+               return 0;
        t = blobmsg_get_u64(tb[LOG_TIME]) / 1000;
        c = ctime(&t);
        p = blobmsg_get_u32(tb[LOG_PRIO]);
@@ -186,6 +191,7 @@ static int usage(const char *prog)
                "Options:\n"
                "    -s <path>          Path to ubus socket\n"
                "    -l <count>         Got only the last 'count' messages\n"
+               "    -e <pattern>       Filter messages with a regexp\n"
                "    -r <server> <port> Stream message to a server\n"
                "    -F <file>          Log file\n"
                "    -S <bytes>         Log size\n"
@@ -235,7 +241,7 @@ int main(int argc, char **argv)
 
        signal(SIGPIPE, SIG_IGN);
 
-       while ((ch = getopt(argc, argv, "u0fcs:l:r:F:p:S:P:h:")) != -1) {
+       while ((ch = getopt(argc, argv, "u0fcs:l:r:F:p:S:P:h:e:")) != -1) {
                switch (ch) {
                case 'u':
                        log_udp = 1;
@@ -274,6 +280,11 @@ int main(int argc, char **argv)
                case 'h':
                        hostname = optarg;
                        break;
+               case 'e':
+                       if (!regcomp(&regexp_preg, optarg, REG_NOSUB)) {
+                               regexp_pattern = optarg;
+                       }
+                       break;
                default:
                        return usage(*argv);
                }