fix(os): Ubuntu 18.04 timezone error.

source/os/src/osTimezone.c

@@ -172,106 +172,108 @@ void taosGetSystemTimezone(char *outTimezoneStr, enum TdTimezone *tsTimezone) {
            -timezone / 3600);
 #else
 
-  if (taosCheckExistFile("/etc/timezone")) {
-    /*
-    * NOTE: do not remove it.
-    * Enforce set the correct daylight saving time(DST) flag according
-    * to current time
-    */
-    time_t    tx1 = taosGetTimestampSec();
-    struct tm tm1;
-    taosLocalTime(&tx1, &tm1);
-    /* load time zone string from /etc/timezone */
-    // FILE *f = fopen("/etc/timezone", "r");
-    errno = 0;
-    TdFilePtr pFile = taosOpenFile("/etc/timezone", TD_FILE_READ);
-    char  buf[68] = {0};
-    if (pFile != NULL) {
-      int len = taosReadFile(pFile, buf, 64);
-      if (len < 64 && taosGetErrorFile(pFile)) {
-        taosCloseFile(&pFile);
-        printf("read /etc/timezone error, reason:%s", strerror(errno));
-        return;
-      }
+  char  buf[4096] = {0};
+  char *tz = NULL;
+  {
+    int n = readlink("/etc/localtime", buf, sizeof(buf));
+    if (n < 0) {
+      printf("read /etc/localtime error, reason:%s", strerror(errno));
+      
+      if (taosCheckExistFile("/etc/timezone")) {
+        /*
+        * NOTE: do not remove it.
+        * Enforce set the correct daylight saving time(DST) flag according
+        * to current time
+        */
+        time_t    tx1 = taosGetTimestampSec();
+        struct tm tm1;
+        taosLocalTime(&tx1, &tm1);
+        /* load time zone string from /etc/timezone */
+        // FILE *f = fopen("/etc/timezone", "r");
+        errno = 0;
+        TdFilePtr pFile = taosOpenFile("/etc/timezone", TD_FILE_READ);
+        char  buf[68] = {0};
+        if (pFile != NULL) {
+          int len = taosReadFile(pFile, buf, 64);
+          if (len < 64 && taosGetErrorFile(pFile)) {
+            taosCloseFile(&pFile);
+            printf("read /etc/timezone error, reason:%s", strerror(errno));
+            return;
+          }
 
-      taosCloseFile(&pFile);
+          taosCloseFile(&pFile);
 
-      buf[sizeof(buf) - 1] = 0;
-      char *lineEnd = strstr(buf, "\n");
-      if (lineEnd != NULL) {
-        *lineEnd = 0;
-      }
+          buf[sizeof(buf) - 1] = 0;
+          char *lineEnd = strstr(buf, "\n");
+          if (lineEnd != NULL) {
+            *lineEnd = 0;
+          }
 
-      // for CentOS system, /etc/timezone does not exist. Ignore the TZ environment variables
-      if (strlen(buf) > 0) {
-        setenv("TZ", buf, 1);
-      }
-    }
-    // get and set default timezone
-    tzset();
-    /*
-    * get CURRENT time zone.
-    * system current time zone is affected by daylight saving time(DST)
-    *
-    * e.g., the local time zone of London in DST is GMT+01:00,
-    * otherwise is GMT+00:00
-    */
-    int32_t tz = (-timezone * MILLISECOND_PER_SECOND) / MILLISECOND_PER_HOUR;
-    *tsTimezone = tz;
-    tz += daylight;
+          // for CentOS system, /etc/timezone does not exist. Ignore the TZ environment variables
+          if (strlen(buf) > 0) {
+            setenv("TZ", buf, 1);
+          }
+        }
+        // get and set default timezone
+        tzset();
+        /*
+        * get CURRENT time zone.
+        * system current time zone is affected by daylight saving time(DST)
+        *
+        * e.g., the local time zone of London in DST is GMT+01:00,
+        * otherwise is GMT+00:00
+        */
+        int32_t tz = (-timezone * MILLISECOND_PER_SECOND) / MILLISECOND_PER_HOUR;
+        *tsTimezone = tz;
+        tz += daylight;
 
-    /*
-    * format example:
-    *
-    * Asia/Shanghai   (CST, +0800)
-    * Europe/London   (BST, +0100)
-    */
-    snprintf(outTimezoneStr, TD_TIMEZONE_LEN, "%s (%s, %s%02d00)", buf, tzname[daylight], tz >= 0 ? "+" : "-", abs(tz));
-  } else {
-    char  buf[4096] = {0};
-    char *tz = NULL;
-    {
-      int n = readlink("/etc/localtime", buf, sizeof(buf));
-      if (n < 0) {
-        printf("read /etc/localtime error, reason:%s", strerror(errno));
-        return;
+        /*
+        * format example:
+        *
+        * Asia/Shanghai   (CST, +0800)
+        * Europe/London   (BST, +0100)
+        */
+        snprintf(outTimezoneStr, TD_TIMEZONE_LEN, "%s (%s, %s%02d00)", buf, tzname[daylight], tz >= 0 ? "+" : "-", abs(tz));
+      } else {
+        printf("There is not /etc/timezone.\n");
       }
-      buf[n] = '\0';
-      for (int i = n - 1; i >= 0; --i) {
-        if (buf[i] == '/') {
-          if (tz) {
-            tz = buf + i + 1;
-            break;
-          }
+      return;
+    }
+    buf[n] = '\0';
+    for (int i = n - 1; i >= 0; --i) {
+      if (buf[i] == '/') {
+        if (tz) {
           tz = buf + i + 1;
+          break;
         }
+        tz = buf + i + 1;
       }
-      if (!tz || 0 == strchr(tz, '/')) {
-        printf("parsing /etc/localtime failed");
-        return;
-      }
-
-      setenv("TZ", tz, 1);
-      tzset();
+    }
+    if (!tz || 0 == strchr(tz, '/')) {
+      printf("parsing /etc/localtime failed");
+      return;
     }
 
-    /*
-    * NOTE: do not remove it.
-    * Enforce set the correct daylight saving time(DST) flag according
-    * to current time
-    */
-    time_t    tx1 = taosGetTimestampSec();
-    struct tm tm1;
-    taosLocalTime(&tx1, &tm1);
-
-    /*
-    * format example:
-    *
-    * Asia/Shanghai   (CST, +0800)
-    * Europe/London   (BST, +0100)
-    */
-    snprintf(outTimezoneStr, TD_TIMEZONE_LEN, "%s (%s, %+03ld00)", tz, tm1.tm_isdst ? tzname[daylight] : tzname[0],
-            -timezone / 3600);
+    setenv("TZ", tz, 1);
+    tzset();
   }
+
+  /*
+  * NOTE: do not remove it.
+  * Enforce set the correct daylight saving time(DST) flag according
+  * to current time
+  */
+  time_t    tx1 = taosGetTimestampSec();
+  struct tm tm1;
+  taosLocalTime(&tx1, &tm1);
+
+  /*
+  * format example:
+  *
+  * Asia/Shanghai   (CST, +0800)
+  * Europe/London   (BST, +0100)
+  */
+  snprintf(outTimezoneStr, TD_TIMEZONE_LEN, "%s (%s, %+03ld00)", tz, tm1.tm_isdst ? tzname[daylight] : tzname[0],
+          -timezone / 3600);
 #endif
 }