[LEDE-DEV] [PATCH ubox] Add template support to logread

Henry Chang mr.changyuheng at gmail.com
Wed Apr 26 22:23:58 PDT 2017 

Hi,

I would like to integrate logd to the cloud logging service. The
service only accepts special format of syslog, so then I make logread
support template.

Here's the usage:

logread -T "<%priority%> %source% %message% %timestamp%"

Currently supports 4 keywords: priority, source, message, timestamp.
The keywords should be surrounded by percent signs as showed above.

Regards,

Henry Chang



Signed-off-by: Henry Chang <mr.changyuheng at gmail.com>
---
 log/logread.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 102 insertions(+), 27 deletions(-)

diff --git a/log/logread.c b/log/logread.c
index edac1d9..ddb4f12 100644
--- a/log/logread.c
+++ b/log/logread.c
@@ -56,10 +56,22 @@ static const struct blobmsg_policy log_policy[] = {
  [LOG_TIME] = { .name = "time", .type = BLOBMSG_TYPE_INT64 },
 };

+static const char TP_FIELD_MESSAGE[] = "%message%";
+static const char TP_FIELD_PRIORITY[] = "%priority%";
+static const char TP_FIELD_SOURCE[] = "%source%";
+static const char TP_FIELD_TIMESTAMP[] = "%timestamp%";
+static const char *TP_FIELD_NAMES[] = {
+ TP_FIELD_MESSAGE,
+ TP_FIELD_PRIORITY,
+ TP_FIELD_SOURCE,
+ TP_FIELD_TIMESTAMP,
+};
+
 static struct uloop_timeout retry;
 static struct uloop_fd sender;
 static regex_t regexp_preg;
 static const char *log_file, *log_ip, *log_port, *log_prefix,
*pid_file, *hostname, *regexp_pattern;
+static const char *log_template;
 static int log_type = LOG_STDOUT;
 static int log_size, log_udp, log_follow, log_trailer_null = 0;
 static int log_timestamp;
@@ -101,13 +113,16 @@ static int log_notify(struct blob_attr *msg)
  struct blob_attr *tb[__LOG_MAX];
  struct stat s;
  char buf[512];
+ char buf2[512];
  char buf_ts[32];
+ char buf_p[32];
  uint32_t p;
- char *str;
+ char *str, *substr, *field;
  time_t t;
  uint32_t t_ms = 0;
  char *c, *m;
  int ret = 0;
+ int i, j;

  if (sender.fd < 0)
  return 0;
@@ -137,34 +152,83 @@ static int log_notify(struct blob_attr *msg)
     regexec(&regexp_preg, m, 0, NULL, 0) == REG_NOMATCH)
  return 0;
  t = blobmsg_get_u64(tb[LOG_TIME]) / 1000;
- if (log_timestamp) {
- t_ms = blobmsg_get_u64(tb[LOG_TIME]) % 1000;
- snprintf(buf_ts, sizeof(buf_ts), "[%lu.%03u] ",
- (unsigned long)t, t_ms);
- }
+ t_ms = blobmsg_get_u64(tb[LOG_TIME]) % 1000;
+ snprintf(buf_ts, sizeof(buf_ts), "[%lu.%03u] ", (unsigned long) t, t_ms);
  c = ctime(&t);
  p = blobmsg_get_u32(tb[LOG_PRIO]);
  c[strlen(c) - 1] = '\0';
  str = blobmsg_format_json(msg, true);
+ snprintf(buf_p, sizeof buf_p, "%u", p);
+
+ if (log_template) {
+ *buf = '\0';
+ *buf2 = '\0';
+ if ((j = strlen(log_template)) + 1 > sizeof buf) {
+ fprintf(stderr, "template is larger than the internal buffer\n");
+ return 1;
+ }
+ strncat(buf, log_template, j);
+ for (i = 0; i < sizeof TP_FIELD_NAMES / sizeof (char *); ++i) {
+ field = NULL;
+ if (!strcmp(TP_FIELD_NAMES[i], TP_FIELD_MESSAGE)) {
+ field = m;
+ } else if (!strcmp(TP_FIELD_NAMES[i], TP_FIELD_PRIORITY)) {
+ field = buf_p;
+ } else if (!strcmp(TP_FIELD_NAMES[i], TP_FIELD_SOURCE)) {
+ switch (blobmsg_get_u32(tb[LOG_SOURCE])) {
+ case SOURCE_KLOG:
+ field = "kernel";
+ break;
+ case SOURCE_SYSLOG:
+ field = "syslog";
+ break;
+ case SOURCE_INTERNAL:
+ field = "internal";
+ break;
+ default:
+ field = "-";
+ }
+ } else if (!strcmp(TP_FIELD_NAMES[i], TP_FIELD_TIMESTAMP)) {
+ field = buf_ts;
+ }
+ while (field && (substr = strstr(buf, TP_FIELD_NAMES[i]))) {
+ if (strlen(field) + strlen(buf) - strlen(TP_FIELD_NAMES[i]) + 1 >
+ sizeof buf) {
+ fprintf(stderr, "content to fill template is larger than buffer\n");
+ return 1;
+ }
+ *buf2 = '\0';
+ strncat(buf2, buf, substr - buf);
+ strncat(buf2, field, strlen(field));
+ strncat(buf2, substr + strlen(TP_FIELD_NAMES[i]),
+ strlen(buf) - (substr - buf) - strlen(TP_FIELD_NAMES[i]));
+ *buf = '\0';
+ strncat(buf, buf2, strlen(buf2));
+ }
+ }
+ }
+
  if (log_type == LOG_NET) {
  int err;

- snprintf(buf, sizeof(buf), "<%u>", p);
- strncat(buf, c + 4, 16);
- if (log_timestamp) {
- strncat(buf, buf_ts, sizeof(buf) - strlen(buf) - 1);
+ if (!log_template) {
+ snprintf(buf, sizeof(buf), "<%u>", p);
+ strncat(buf, c + 4, 16);
+ if (log_timestamp) {
+ strncat(buf, buf_ts, sizeof(buf) - strlen(buf) - 1);
+ }
+ if (hostname) {
+ strncat(buf, hostname, sizeof(buf) - strlen(buf) - 1);
+ strncat(buf, " ", sizeof(buf) - strlen(buf) - 1);
+ }
+ if (log_prefix) {
+ strncat(buf, log_prefix, sizeof(buf) - strlen(buf) - 1);
+ strncat(buf, ": ", sizeof(buf) - strlen(buf) - 1);
+ }
+ if (blobmsg_get_u32(tb[LOG_SOURCE]) == SOURCE_KLOG)
+ strncat(buf, "kernel: ", sizeof(buf) - strlen(buf) - 1);
+ strncat(buf, m, sizeof(buf) - strlen(buf) - 1);
  }
- if (hostname) {
- strncat(buf, hostname, sizeof(buf) - strlen(buf) - 1);
- strncat(buf, " ", sizeof(buf) - strlen(buf) - 1);
- }
- if (log_prefix) {
- strncat(buf, log_prefix, sizeof(buf) - strlen(buf) - 1);
- strncat(buf, ": ", sizeof(buf) - strlen(buf) - 1);
- }
- if (blobmsg_get_u32(tb[LOG_SOURCE]) == SOURCE_KLOG)
- strncat(buf, "kernel: ", sizeof(buf) - strlen(buf) - 1);
- strncat(buf, m, sizeof(buf) - strlen(buf) - 1);
  if (log_udp)
  err = write(sender.fd, buf, strlen(buf));
  else {
@@ -183,11 +247,18 @@ static int log_notify(struct blob_attr *msg)
  uloop_timeout_set(&retry, 1000);
  }
  } else {
- snprintf(buf, sizeof(buf), "%s %s%s.%s%s %s\n",
- c, log_timestamp ? buf_ts : "",
- getcodetext(LOG_FAC(p) << 3, facilitynames),
- getcodetext(LOG_PRI(p), prioritynames),
- (blobmsg_get_u32(tb[LOG_SOURCE])) ? ("") : (" kernel:"), m);
+ if (!log_template) {
+ snprintf(buf, sizeof(buf), "%s %s%s.%s%s %s\n",
+ c, log_timestamp ? buf_ts : "",
+ getcodetext(LOG_FAC(p) << 3, facilitynames),
+ getcodetext(LOG_PRI(p), prioritynames),
+ (blobmsg_get_u32(tb[LOG_SOURCE])) ? ("") : (" kernel:"), m);
+ } else {
+ size_t buflen = strlen(buf);
+ buflen = buflen <= sizeof buf - 2 ? buflen : sizeof buf - 2;
+ buf[buflen] = '\n';
+ buf[buflen+1] = '\0';
+ }
  ret = write(sender.fd, buf, strlen(buf));
  }

@@ -211,6 +282,7 @@ static int usage(const char *prog)
  "    -p <file> PID file\n"
  "    -h <hostname> Add hostname to the message\n"
  "    -P <prefix> Prefix custom text to streamed messages\n"
+ "    -T <template> Custom log output template\n"
  "    -f Follow log messages\n"
  "    -u Use UDP as the protocol\n"
  "    -t Add an extra timestamp\n"
@@ -260,7 +332,7 @@ int main(int argc, char **argv)

  signal(SIGPIPE, SIG_IGN);

- while ((ch = getopt(argc, argv, "u0fcs:l:r:F:p:S:P:h:e:t")) != -1) {
+ while ((ch = getopt(argc, argv, "u0fcs:l:r:F:p:S:P:h:e:tT:")) != -1) {
  switch (ch) {
  case 'u':
  log_udp = 1;
@@ -307,6 +379,9 @@ int main(int argc, char **argv)
  case 't':
  log_timestamp = 1;
  break;
+ case 'T':
+ log_template = optarg;
+ break;
  default:
  return usage(*argv);
  }
-- 
2.7.4

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