Add wallclock time handling

New application and new example.
We use the built-in timer routines and add an offset to get the
wallclock time. The offset can be set by time-changing routines
(currently only settimeofday).
We also maintain an offset for timezone handling but this isn't
currently fully implemented.

apps/time/Makefile.time

@@ -0,0 +1 @@
+time_src = time.c resource_gmtime.c resource_timestamp.c

apps/time/resource_gmtime.c

@@ -0,0 +1,126 @@
+/**
+ * \file
+ *      Resource for gmtime (utc) / localtime handling
+ * \author
+ *      Ralf Schlatterbeck <rsc@runtux.com>
+ *
+ * \brief get time as a string in utc or localtime
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "contiki.h"
+#include "time.h"
+#include "time_resource.h"
+#include "jsonparse.h"
+/* Only coap 13 for now */
+#include "er-coap-13.h"
+
+RESOURCE \
+    ( localtime
+    , METHOD_GET
+    , "clock/localtime"
+    , "title=\"Time\";rt=\"localtime\""
+    );
+
+RESOURCE \
+    ( gmtime
+    , METHOD_GET
+    , "clock/utc"
+    , "title=\"Time\";rt=\"utc\""
+    );
+
+void
+time_handler
+    ( void* request
+    , void* response
+    , uint8_t *buffer
+    , uint16_t preferred_size
+    , int32_t *offset
+    , struct tm *(*method)(const time_t *,struct tm *)
+    )
+{
+  int success = 1;
+
+  char temp[100];
+  int index = 0;
+  int length = 0; /*           |<-------->| */
+  struct timeval tv;
+  struct tm tm;
+  int i = 0;
+  int n_acc = 0;
+  const uint16_t *accept = NULL;
+  uint16_t a_ctype = REST.type.APPLICATION_JSON; /* for now json is default */
+
+  /* Looks like accepted content-type isn't currently supported */
+  n_acc = REST.get_header_accept (request, &accept);
+  for (i=0; i<n_acc; i++) {
+    if  (  accept [i] == REST.type.TEXT_PLAIN
+        || accept [i] == REST.type.APPLICATION_JSON
+        )
+    {
+      a_ctype = accept [i];
+      break;
+    }
+  }
+
+  switch(REST.get_method_type(request)){
+    case METHOD_GET:
+      gettimeofday (&tv, NULL);
+      method (&tv.tv_sec, &tm);
+      if (a_ctype == REST.type.TEXT_PLAIN) {
+        index += sprintf
+          ( temp + index
+          , "%lu-%02u-%02u %02u:%02u:%02u\n"
+          , 1900 + tm.tm_year
+          , tm.tm_mon, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec
+          );
+      } else { // jSON Format
+        index += sprintf
+          ( temp + index
+          ,"{\n \"localtime\" : \"%lu-%02u-%02u %02u:%02u:%02u\"\n"
+          , 1900 + tm.tm_year
+          , tm.tm_mon, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec
+          );
+        index += sprintf(temp + index,"}\n");
+      }
+      length = strlen(temp);
+      memcpy (buffer, temp, length);
+      REST.set_header_content_type (response, REST.type.APPLICATION_JSON);
+      REST.set_response_payload (response, buffer, length);
+
+      break;
+    default:
+      success = 0;
+  }
+  if (!success) {
+    REST.set_response_status(response, REST.status.BAD_REQUEST);
+  }
+}
+
+void
+localtime_handler
+    ( void* request
+    , void* response
+    , uint8_t *buffer
+    , uint16_t preferred_size
+    , int32_t *offset
+    )
+{
+    return time_handler
+        (request, response, buffer, preferred_size, offset, &localtime_r);
+}
+
+void
+gmtime_handler
+    ( void* request
+    , void* response
+    , uint8_t *buffer
+    , uint16_t preferred_size
+    , int32_t *offset
+    )
+{
+    return time_handler
+        (request, response, buffer, preferred_size, offset, &gmtime_r);
+}

apps/time/resource_timestamp.c

@@ -0,0 +1,158 @@
+/**
+ * \file
+ *      Resource for timestamp handling
+ * \author
+ *      Ralf Schlatterbeck <rsc@runtux.com>
+ *
+ * \brief get/put time in seconds since 1970 (UNIX time)
+ * Note: the internal format of the time in seconds is a 64bit number
+ * unfortunately javascript (json) will only support double for which
+ * the mantissa isn't long enough for representing that number. So we're
+ * back to 32 bit and have a year 2038 problem.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "contiki.h"
+#include "time.h"
+#include "time_resource.h"
+#include "jsonparse.h"
+/* Only coap 13 for now */
+#include "er-coap-13.h"
+
+/* Error-handling macro */
+# define BYE(_exp, _tag) \
+   do {                                  \
+     PRINTF("Expect "_exp": %d\n",_tag); \
+     success=0;                          \
+     goto bye;                           \
+   } while(0)
+
+#define DEBUG 1
+#if DEBUG
+#define PRINTF(...) printf(__VA_ARGS__)
+#else
+#define PRINTF(...)
+#endif
+
+RESOURCE \
+    ( timestamp, METHOD_GET | METHOD_PUT
+    , "clock/timestamp"
+    , "title=\"Time\";rt=\"timestamp\""
+    );
+
+void
+timestamp_handler
+    ( void* request
+    , void* response
+    , uint8_t *buffer
+    , uint16_t preferred_size
+    , int32_t *offset
+    )
+{
+  int success = 1;
+
+  int i;
+  char temp[100];
+  int index = 0;
+  int length = 0;
+  int tag = 0;
+  const uint8_t *bytes = NULL;
+  size_t len = 0;
+  struct timeval tv;
+  int n_acc = 0;
+  const uint16_t *accept = NULL;
+  uint16_t a_ctype = REST.type.APPLICATION_JSON;
+  uint16_t c_ctype = REST.get_header_content_type (request);
+
+  /* Seems like accepted type is currently unsupported? */
+  n_acc = REST.get_header_accept (request, &accept);
+  for (i=0; i<n_acc; i++) {
+    if  (  accept [i] == REST.type.TEXT_PLAIN
+        || accept [i] == REST.type.APPLICATION_JSON
+        )
+    {
+      a_ctype = accept [i];
+      break;
+    }
+  }
+
+  switch(REST.get_method_type(request)) {
+    case METHOD_GET:
+      gettimeofday (&tv, NULL);
+      // TEXT format
+      if (a_ctype == REST.type.TEXT_PLAIN) {
+        index += sprintf (temp + index, "%ld\n", (long)tv.tv_sec);
+      } else { // jSON Format
+        // FIXME: Platform doesn't seem to support long long printing
+        // We get empty string
+        index += sprintf
+          ( temp + index
+          ,"{\n \"timestamp\" : \"%ld\"\n}\n"
+          , (long)tv.tv_sec
+          );
+      }
+      length = strlen(temp);
+      memcpy (buffer, temp, length);
+      REST.set_header_content_type (response, a_ctype);
+      REST.set_response_payload (response, buffer, length);
+
+      break;
+    case METHOD_PUT:
+      if ((len = coap_get_payload(request, &bytes))) {
+        if (c_ctype == REST.type.TEXT_PLAIN) {
+          temp [sizeof (temp) - 1] = 0;
+          strncpy (temp, (char *)bytes, MIN (len, sizeof (temp) - 1));
+        } else { // jSON Format
+          struct jsonparse_state state;
+          struct jsonparse_state *parser = &state;
+          PRINTF ("PUT: len: %d, %s\n", len, (char *)bytes);
+          jsonparse_setup (parser, (char *)bytes, len);
+          if ((tag = jsonparse_next (parser)) != JSON_TYPE_OBJECT) {
+            BYE ("OBJECT", tag);
+          }
+          if ((tag = jsonparse_next (parser)) != JSON_TYPE_PAIR_NAME) {
+            BYE ("PAIR_NAME", tag);
+          }
+          while (jsonparse_strcmp_value (parser, "timestamp") != 0) {
+            tag = jsonparse_next (parser);
+            if (tag != JSON_TYPE_PAIR) {
+              BYE ("PAIR", tag);
+            }
+            tag = jsonparse_next (parser);
+            tag = jsonparse_next (parser);
+            if (tag != ',') {
+              BYE (",", tag);
+            }
+            tag = jsonparse_next (parser);
+            if (tag != JSON_TYPE_PAIR_NAME) {
+              BYE ("PAIR_NAME", tag);
+            }
+          }
+          tag = jsonparse_next (parser);
+          if (tag != JSON_TYPE_PAIR) {
+            BYE ("PAIR", tag);
+          }
+          tag = jsonparse_next (parser);
+          if (tag != JSON_TYPE_STRING) {
+            BYE ("STRING", tag);
+          }
+          jsonparse_copy_value (parser, temp, sizeof (temp));
+        }
+        // FIXME: Platform has no strtoll (long long)?
+        tv.tv_sec = strtol (temp, NULL, 10);
+        settimeofday (&tv, NULL);
+        REST.set_response_status(response, REST.status.CHANGED);
+      } else {
+        success = 0;
+      }
+      bye :
+      break;
+    default:
+      success = 0;
+  }
+  if (!success) {
+    REST.set_response_status(response, REST.status.BAD_REQUEST);
+  }
+}

apps/time/time.c

@@ -0,0 +1,165 @@
+/**
+ * \addgroup Time related functions
+ *
+ * @{
+ */
+#include <errno.h>
+#include "contiki.h"
+#include "contiki-lib.h"
+#include "time.h"
+
+/* Used for gmtime and localtime, according to manpage on linux the
+ * internal value may be overwritten "by subsequent calls to any of the
+ * date  and  time  functions".
+ */
+static struct tm tm;
+
+/*
+ * Internal variables to manage offset of utc from the contiki clock
+ * and timezone offset from utc in minutes.
+ * For now we don't manage the sub-second offset -- time of setting the
+ * clock and the precisiont of the clock in use don't warrant this
+ * effort.
+ * The last_seconds is used to check if we had a seconds overflow,
+ * although this happens only every 136 years :-)
+ */
+time_t   clock_offset;
+uint32_t last_seconds;
+int16_t  minuteswest;
+
+# define LEAP_YEAR(_year) \
+    ((_year % 4) == 0 && (_year % 100 != 0 || _year % 400 == 0))
+# define YDAYS(_year) (LEAP_YEAR(year) ? 366 : 365)
+
+struct tm *
+gmtime_r (const time_t *timep, struct tm *ptm)
+{
+    unsigned int year;
+    int days, month, month_len;
+    time_t t = *timep;
+    ptm->tm_sec = t % 60;
+    t /= 60;
+    ptm->tm_min = t % 60;
+    t /= 60;
+    ptm->tm_hour = t % 24;
+    t /= 24;
+    ptm->tm_wday = (t+4) % 7;
+    year = 70;
+    days =  0;
+    while ((days += YDAYS (year)) <= t)
+    {
+        year++;
+    }
+    ptm->tm_year = year;
+    days -= YDAYS(year);
+    t    -= days;
+    ptm->tm_yday = t;
+    for (month=0; month<12; month++)
+    {
+        if (month == 1)
+        {
+            month_len = LEAP_YEAR(year) ? 29 : 28;
+        }
+        else
+        {
+            int m = month;
+            if (m >= 7)
+            {
+                m -= 1;
+            }
+            m &= 1;
+            month_len = m ? 30 : 31;
+        }
+        if (t >= month_len)
+        {
+            t -= month_len;
+        }
+        else
+        {
+            break;
+        }
+    }
+    ptm->tm_mon   = month;
+    ptm->tm_mday  = t + 1;
+    ptm->tm_isdst = 0;
+    return ptm;
+}
+
+struct tm *
+gmtime (const time_t *timep)
+{
+    return gmtime_r (timep, &tm);
+}
+
+struct tm *
+localtime_r (const time_t *timep, struct tm *ptm)
+{
+    time_t t = *timep;
+    t += minuteswest * 60;
+    return gmtime_r (&t, ptm);
+}
+
+struct tm *
+localtime (const time_t *timep)
+{
+    return localtime_r (timep, &tm);
+}
+
+/**
+ * \brief Get time in seconds and microseconds
+ * gettimeofday will return the clock time as the microseconds part
+ * while settimeofday will *ignore* the microseconds part (for now).
+ * Note that the contiki clock interface is broken anyway, we can't read
+ * seconds and sub-seconds atomically. We try to work around this by
+ * repeatedly reading seconds, sub-seconds, seconds until first and
+ * second read of seconds match.
+ */
+int
+gettimeofday (struct timeval *tv, struct timezone *tz)
+{
+    uint32_t cs;
+    if (tz) {
+        tz->tz_minuteswest = minuteswest;
+        tz->tz_dsttime     = 0;
+    }
+    if (tv) {
+        int i;
+        /* Limit tries to get the same second twice to two */
+        for (i=0; i<2; i++) {
+            cs = clock_seconds ();
+            if (cs < last_seconds) {
+                clock_offset += 0xFFFFFFFFL;
+                clock_offset ++;
+            }
+            last_seconds = cs;
+            tv->tv_sec = cs + clock_offset;
+            tv->tv_usec = ((time_t)(clock_time () % CLOCK_SECOND))
+                        * 1000000L / CLOCK_SECOND;
+            if (cs == clock_seconds ()) {
+                break;
+            }
+        }
+    }
+    return 0;
+}
+
+/**
+ * \brief Set time in seconds, microseconds ignored for now
+ */
+int
+settimeofday (const struct timeval *tv, const struct timezone *tz)
+{
+    /* Don't allow setting timezone */
+    if (tz) {
+        errno = ERANGE;
+        return -1;
+    }
+    if (tv) {
+        uint32_t cs;
+        cs = clock_seconds ();
+        clock_offset = tv->tv_sec - cs;
+    }
+    return 0;
+}
+
+/** @} */

apps/time/time.h

@@ -0,0 +1,65 @@
+/**
+ * \defgroup Time related functions
+ *
+ * This rolls the necessary definition for getting/setting time and
+ * managing local time into one include file, on posix systems this
+ * lives in at least two include files, time.h and sys/time.h
+ *
+ * @{
+ */
+
+/**
+ * \file
+ *         Definitions for the time module
+ *      
+ * \author
+ *         Ralf Schlatterbeck <rsc@tux.runtux.com>
+ */
+
+#ifndef time_h
+#define time_h
+
+
+typedef signed long long time_t;
+typedef signed long      suseconds_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct tm {
+    uint32_t tm_year;        /* year */
+    uint16_t tm_yday;        /* day in the year */
+    uint8_t  tm_sec;         /* seconds */
+    uint8_t  tm_min;         /* minutes */
+    uint8_t  tm_hour;        /* hours */
+    uint8_t  tm_mday;        /* day of the month */
+    uint8_t  tm_mon;         /* month */
+    uint8_t  tm_wday;        /* day of the week */
+    uint8_t  tm_isdst;       /* daylight saving time */
+};
+
+struct timeval {
+    time_t      tv_sec;     /* seconds */
+    suseconds_t tv_usec;    /* microseconds */
+};
+
+struct timezone {
+    int16_t tz_minuteswest;     /* minutes west of Greenwich */
+    int     tz_dsttime;         /* type of DST correction, unused */
+};
+
+struct tm *gmtime      (const time_t *timep);
+struct tm *gmtime_r    (const time_t *timep, struct tm *result);
+struct tm *localtime   (const time_t *timep);
+struct tm *localtime_r (const time_t *timep, struct tm *result);
+
+int gettimeofday       (struct timeval *tv, struct timezone *tz);
+int settimeofday       (const struct timeval *tv, const struct timezone *tz);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // time_h
+/** @} */

apps/time/time_resource.h

@@ -0,0 +1,27 @@
+/**
+ * \addgroup Time related functions
+ *
+ * Resource definitions for time module
+ *
+ * @{
+ */
+
+/**
+ * \file
+ *         Resource definitions for the time module
+ *      
+ * \author
+ *         Ralf Schlatterbeck <rsc@tux.runtux.com>
+ */
+
+#ifndef time_resource_h
+#define time_resource_h
+#include "contiki.h"
+#include "erbium.h"
+
+extern resource_t resource_timestamp;
+extern resource_t resource_localtime;
+extern resource_t resource_gmtime;
+
+#endif // time_resource_h
+/** @} */