PROC_FDINFO plugin for workshop

plugin/proc_info/mysql-test/proc_info/fdinfo.test

+SHOW CREATE TABLE INFORMATION_SCHEMA.PROC_FDINFO;
+query_vertical SELECT PLUGIN_NAME, PLUGIN_VERSION, PLUGIN_TYPE, PLUGIN_AUTHOR, PLUGIN_DESCRIPTION, PLUGIN_LICENSE, PLUGIN_MATURITY FROM INFORMATION_SCHEMA.PLUGINS WHERE PLUGIN_NAME='proc_fdinfo';
+SELECT * FROM INFORMATION_SCHEMA.PROC_FDINFO;
+FLUSH TABLES;
+SELECT * FROM INFORMATION_SCHEMA.PROC_FDINFO;

plugin/proc_info/proc_info.cc

@@ -3,6 +3,7 @@
 #include <sql_show.h>
 #include <sql_class.h>
 #include <mysql/plugin.h>
+#include <dirent.h>
 
 
 static ST_FIELD_INFO meminfo_fields[]=
@@ -58,6 +59,77 @@ static struct st_mysql_information_schema meminfo_plugin=
 { MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION };
 
 
+static ST_FIELD_INFO fdinfo_fields[]=
+{
+  { "NAME", 100, MYSQL_TYPE_STRING, 0, 0, 0, SKIP_OPEN_TABLE },
+  { "VALUE", FN_REFLEN, MYSQL_TYPE_STRING, 0, MY_I_S_MAYBE_NULL, 0,
+    SKIP_OPEN_TABLE },
+  { 0, 0, MYSQL_TYPE_STRING, 0, 0, 0, 0 }
+};
+
+
+static int fdinfo_fill(MYSQL_THD thd, TABLE_LIST *tables, COND *cond)
+{
+  TABLE *table= tables->table;
+  int fd;
+  DIR *dir;
+  struct dirent dirbuf, *result;
+
+  if ((fd= open("/proc/self/fd", O_DIRECTORY)) < 0)
+    return 1;
+  if (!(dir= fdopendir(fd)))
+  {
+    close(fd);
+    return 1;
+  }
+
+  while (readdir_r(dir, &dirbuf, &result) == 0 && result)
+  {
+    char buf[FN_REFLEN];
+    ssize_t len;
+
+    if (result->d_name[0] == '.')
+      continue;
+    len= readlinkat(fd, result->d_name, buf, sizeof(buf));
+
+    table->field[0]->store(result->d_name, strlen(result->d_name), system_charset_info);
+    if (len < 0)
+      table->field[1]->set_null();
+    else
+    {
+      table->field[1]->store(buf, len, system_charset_info);
+      table->field[1]->set_notnull();
+    }
+
+    if (schema_table_store_record(thd, table))
+    {
+      close(fd);
+      closedir(dir);
+      return 1;
+    }
+  }
+  close(fd);
+  closedir(dir);
+
+  return 0;
+}
+
+
+static int fdinfo_init(void *p)
+{
+  ST_SCHEMA_TABLE *schema= (ST_SCHEMA_TABLE *) p;
+
+  schema->fields_info= fdinfo_fields;
+  schema->fill_table= fdinfo_fill;
+
+  return 0;
+}
+
+
+static struct st_mysql_information_schema fdinfo_plugin=
+{ MYSQL_INFORMATION_SCHEMA_INTERFACE_VERSION };
+
+
 maria_declare_plugin(proc_info)
 {
   MYSQL_INFORMATION_SCHEMA_PLUGIN, /* type                */
@@ -73,5 +145,20 @@ maria_declare_plugin(proc_info)
   NULL,                            /* system variables    */
   "1.0",                           /* version as a string */
   MariaDB_PLUGIN_MATURITY_EXPERIMENTAL
+},
+{
+  MYSQL_INFORMATION_SCHEMA_PLUGIN, /* type                */
+  &fdinfo_plugin,                  /* information schema  */
+  "PROC_FDINFO",                   /* name                */
+  ""      ,                        /* author              */
+  "Useful information from /proc", /* description         */
+  PLUGIN_LICENSE_BSD,              /* license             */
+  fdinfo_init,                     /* init callback       */
+  0,                               /* deinit callback     */
+  0x0100,                          /* version as hex      */
+  NULL,                            /* status variables    */
+  NULL,                            /* system variables    */
+  "1.0",                           /* version as a string */
+  MariaDB_PLUGIN_MATURITY_EXPERIMENTAL
 }
 maria_declare_plugin_end;