logd: missing klogd content

- regression in log_strtok_r (part deux) In commit
      'logd: fix kernel logline stutter'
  2c3b300fd8307e8da13608197d0a89bc613de5fb we introduced log_strtok_r.
  as a replacement for strtok_r that dealt with a problem with
  some kernel log messages. Fix is to refine definition of
  is_timestamp to not match on patterns like [0], requiring
  a single period. Another fix is to refine definition of
  is_prio to properly escape non-digit content.
- Missing content because SYSLOG_ACTION_SIZE_BUFFER with added logging
  is too short for full read of SYSLOG_ACTION_READ_ALL dropping
  initial content. Add a margin for additional 1024 bytes.
- Absolute _first_ log entry has sequence number of 1, which is
  specifically dropped, start sequence count at 1 rather than 0.
- Remove trailing space for efficiency.
- If tag exists but no content, trick into kernel logging.

Bug: 21851884
Change-Id: I0867a555a3bca09bbf18d18e75e41dffffe57a23

1 files changed, 19 insertions, 9 deletions

diff --git a/logd/LogKlog.cpp b/logd/LogKlog.cpp
index 7d1464899..d578c04db 100644
--- a/logd/LogKlog.cpp
+++ b/logd/LogKlog.cpp
@@ -45,8 +45,8 @@ static char *is_prio(char *s) {
     }
     char c;
     while ((c = *s++)) {
-        if (!isdigit(c) && (c == '>')) {
-            return s;
+        if (!isdigit(c)) {
+            return (c == '>') ? s : NULL;
         }
     }
     return NULL;
@@ -65,17 +65,15 @@ static char *is_timestamp(char *s) {
     while ((c = *s++)) {
         if ((c == '.') && first_period) {
             first_period = false;
-            continue;
-        }
-        if (!isdigit(c) && (c == ']')) {
-            return s;
+        } else if (!isdigit(c)) {
+            return ((c == ']') && !first_period && (*s == ' ')) ? s : NULL;
         }
     }
     return NULL;
 }
 
 // Like strtok_r with "\r\n" except that we look for log signatures (regex)
-//   \(\(<[0-9]+>\)\([[] *[0-9]+[]]\)\{0,1\}\|[[] *[0-9]+[]]\)
+// \(\(<[0-9]+>\)\([[] *[0-9]+[.][0-9]+[]] \)\{0,1\}\|[[] *[0-9]+[.][0-9]+[]] \)
 // and split if we see a second one without a newline.
 
 #define SIGNATURE_MASK     0xF0
@@ -547,10 +545,21 @@ int LogKlog::log(const char *buf) {
         }
     }
     size_t l = etag - tag;
+    // skip leading space
     while (isspace(*buf)) {
         ++buf;
     }
-    size_t n = 1 + l + 1 + strlen(buf) + 1;
+    // truncate trailing space
+    size_t b = strlen(buf);
+    while (b && isspace(buf[b-1])) {
+        --b;
+    }
+    // trick ... allow tag with empty content to be logged. log() drops empty
+    if (!b && l) {
+        buf = " ";
+        b = 1;
+    }
+    size_t n = 1 + l + 1 + b + 1;
 
     // Allocate a buffer to hold the interpreted log message
     int rc = n;
@@ -572,7 +581,8 @@ int LogKlog::log(const char *buf) {
     ++np;
 
     // Copy main message to the remainder
-    strcpy(np, buf);
+    strncpy(np, buf, b);
+    np[b] = '\0';
 
     // Log message
     rc = logbuf->log(LOG_ID_KERNEL, now, uid, pid, tid, newstr,