logd: initial checkin.

* Create a new userspace log daemon for handling logging messages.

Original-Change-Id: I75267df16359684490121e6c31cca48614d79856
Signed-off-by: Nick Kralevich <nnk@google.com>

* Merge conflicts
* rename new syslog daemon to logd to prevent confusion with bionic syslog
* replace racy getGroups call with KISS call to client->getGid()
* Timestamps are filed at logging source
* insert entries into list in timestamp order
* Added LogTimeEntry tail filtration handling
* Added region locking around LogWriter list
* separate threads for each writer
* /dev/socket/logd* permissions

Signed-off-by: Mark Salyzyn <salyzyn@google.com>

(cherry picked from commit 3e76e0a49760c4970b7cda6153e51026af98e4f3)

Author: Nick Kralevich <nnk@google.com>
Change-Id: Ice88b1412d8f9daa7f9119b2b5aaf684a5e28098

3 files changed, 22 insertions, 8 deletions

diff --git a/include/log/log_read.h b/include/log/log_read.h
index 861c192..2601622 100644
--- a/include/log/log_read.h
+++ b/include/log/log_read.h
@@ -23,12 +23,12 @@
 #ifdef __cplusplus
 struct log_time : public timespec {
 public:
-    log_time(timespec &T)
+    log_time(const timespec &T)
     {
         tv_sec = T.tv_sec;
         tv_nsec = T.tv_nsec;
     }
-    log_time(void)
+    log_time()
     {
     }
     log_time(clockid_t id)
@@ -67,7 +67,7 @@ public:
     {
         return !(*this > T);
     }
-    uint64_t nsec(void) const
+    uint64_t nsec() const
     {
         return static_cast<uint64_t>(tv_sec) * NS_PER_SEC + tv_nsec;
     }
diff --git a/include/log/logger.h b/include/log/logger.h
index 966397a..6414d84 100644
--- a/include/log/logger.h
+++ b/include/log/logger.h
@@ -35,7 +35,7 @@ struct logger_entry {
 /*
  * The userspace structure for version 2 of the logger_entry ABI.
  * This structure is returned to userspace if ioctl(LOGGER_SET_VERSION)
- * is called with version==2
+ * is called with version==2; or used with the user space log daemon.
  */
 struct logger_entry_v2 {
     uint16_t    len;       /* length of the payload */
@@ -48,6 +48,17 @@ struct logger_entry_v2 {
     char        msg[0];    /* the entry's payload */
 };
 
+struct logger_entry_v3 {
+    uint16_t    len;       /* length of the payload */
+    uint16_t    hdr_size;  /* sizeof(struct logger_entry_v2) */
+    int32_t     pid;       /* generating process's pid */
+    int32_t     tid;       /* generating process's tid */
+    int32_t     sec;       /* seconds since Epoch */
+    int32_t     nsec;      /* nanoseconds */
+    uint32_t    lid;       /* log id of the payload */
+    char        msg[0];    /* the entry's payload */
+};
+
 /*
  * The maximum size of the log entry payload that can be
  * written to the kernel logger driver. An attempt to write
@@ -69,6 +80,7 @@ struct log_msg {
     union {
         unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1];
         struct logger_entry_v2 entry;
+        struct logger_entry_v3 entry_v3;
         struct logger_entry_v2 entry_v2;
         struct logger_entry    entry_v1;
         struct {
@@ -106,21 +118,21 @@ struct log_msg {
     {
         return !(*this > T);
     }
-    uint64_t nsec(void) const
+    uint64_t nsec() const
     {
         return static_cast<uint64_t>(entry.sec) * NS_PER_SEC + entry.nsec;
     }
 
     /* packet methods */
-    log_id_t id(void)
+    log_id_t id()
     {
         return extra.id;
     }
-    char *msg(void)
+    char *msg()
     {
         return entry.hdr_size ? (char *) buf + entry.hdr_size : entry_v1.msg;
     }
-    unsigned int len(void)
+    unsigned int len()
     {
         return (entry.hdr_size ? entry.hdr_size : sizeof(entry_v1)) + entry.len;
     }
diff --git a/include/private/android_filesystem_config.h b/include/private/android_filesystem_config.h
index 0ed0d78..9c26baf 100644
--- a/include/private/android_filesystem_config.h
+++ b/include/private/android_filesystem_config.h
@@ -76,6 +76,7 @@
 #define AID_SDCARD_PICS   1033  /* external storage photos access */
 #define AID_SDCARD_AV     1034  /* external storage audio/video access */
 #define AID_SDCARD_ALL    1035  /* access all users external storage */
+#define AID_LOGD          1036  /* log daemon */
 
 #define AID_SHELL         2000  /* adb and debug shell user */
 #define AID_CACHE         2001  /* cache access */
@@ -151,6 +152,7 @@ static const struct android_id_info android_ids[] = {
     { "sdcard_pics",   AID_SDCARD_PICS, },
     { "sdcard_av",     AID_SDCARD_AV, },
     { "sdcard_all",    AID_SDCARD_ALL, },
+    { "logd",          AID_LOGD, },
 
     { "shell",         AID_SHELL, },
     { "cache",         AID_CACHE, },