Move getopt() variables into TLS

getopt() in the FLAT build environment is not thread safe.  This is because global variables that are process-specific in Unix are truly global in the FLAT build.  Moving the getopt() variables into TLS resolves this issue.

No side-effects are expected other than to getopt()

Tested with sim:nsh

include/nuttx/lib/getopt.h

@@ -0,0 +1,89 @@
+/****************************************************************************
+ * include/nuttx/lib/getopt.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_LIB_GETOPT_H
+#define __INCLUDE_NUTTX_LIB_GETOPT_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdbool.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define GETOPT_INIITIALIZER() = \
+  { \
+    NULL, \
+    0, \
+    1, \
+    '?' \
+    NULL, \
+    false \
+  }
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/* This structure encapsulates all variables associated with getopt(). */
+
+struct getopt_s
+{
+  /* Part of the implementation of the public getopt() interface */
+
+  FAR char *go_optarg;       /* Optional argument following option */
+  int       go_opterr;       /* Print error message */
+  int       go_optind;       /* Index into argv */
+  int       go_optopt;       /* unrecognized option character */
+
+  /* Internal getopt() state */
+
+  FAR char *go_optptr;       /* Current parsing location */
+  bool      go_binitialized; /* true:  getopt() has been initialized */
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __INCLUDE_NUTTX_LIB_GETOPT_H */

include/nuttx/lib/libvars.h

@@ -0,0 +1,76 @@
+/****************************************************************************
+ * include/nuttx/lib/libvars.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_LIB_LIBVARS_H
+#define __INCLUDE_NUTTX_LIB_LIBVARS_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdbool.h>
+
+#include <nuttx/lib/getopt.h>
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+#ifndef CONFIG_BUILD_KERNEL
+/* This structure encapsulates all task-specific variables needed by the C
+ * Library.  This structure is retained at the beginning of the main thread
+ * of and is accessed via a reference stored in the TLS of all threads in
+ * the task group.
+ *
+ * NOTE: task-specific variables are not needed in the KERNEL build.  In
+ * that build mode, all global variables are inherently process-specific.
+ */
+
+struct libvars_s
+{
+  struct getopt_s lv_getopt; /* Globals used by getopt() */
+};
+#endif
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __INCLUDE_NUTTX_LIB_LIBVARS_H */

include/nuttx/sched.h

@@ -38,6 +38,7 @@
 #include <nuttx/clock.h>
 #include <nuttx/irq.h>
 #include <nuttx/wdog.h>
+#include <nuttx/lib/libvars.h>
 #include <nuttx/mm/shm.h>
 #include <nuttx/fs/fs.h>
 #include <nuttx/net/net.h>
@@ -529,6 +530,12 @@ struct task_group_s
   tls_ndxset_t tg_tlsset;           /* Set of TLS data indexes allocated        */
 #endif
 
+  /* Task-specific Data *********************************************************/
+
+#ifndef CONFIG_BUILD_KERNEL
+  FAR struct libvars_s *tg_libvars; /* C library global variables */
+#endif
+
   /* POSIX Signal Control Fields ************************************************/
 
   sq_queue_t tg_sigactionq;         /* List of actions for signals              */

include/nuttx/tls.h

@@ -78,6 +78,7 @@ struct tls_info_s
 #if CONFIG_TLS_NELEM > 0
   uintptr_t tl_elem[CONFIG_TLS_NELEM]; /* TLS elements */
 #endif
+  FAR struct libvars_s *tl_libvars;    /* Task-specific C library data */
   int tl_errno;                        /* Per-thread error number */
 };
 

include/unistd.h

@@ -260,6 +260,13 @@
 #define getdtablesize(f)                 ((int)sysconf(_SC_OPEN_MAX))
 #define getpagesize(f)                   ((int)sysconf(_SC_PAGESIZE))
 
+/* Accessor functions associated with getopt(). */
+
+#define optarg  (*(getoptargp()))
+#define opterr  (*(getopterrp()))
+#define optind  (*(getoptindp()))
+#define optopt  (*(getoptoptp()))
+
 /****************************************************************************
  * Public Data
  ****************************************************************************/
@@ -273,23 +280,6 @@ extern "C"
 #define EXTERN extern
 #endif
 
-/* Used by getopt (obviously NOT thread safe!).  These variables cannot be
- * accessed directly by an external NXFLAT module.  In that case, accessor
- * functions must be used.
- */
-
-#ifndef __NXFLAT__
-EXTERN FAR char *optarg; /* Optional argument following option */
-EXTERN int       opterr; /* Print error message */
-EXTERN int       optind; /* Index into argv */
-EXTERN int       optopt; /* Unrecognized option character */
-#else
-#  define optarg  (*(getoptargp()))
-#  define opterr  (*(getopterrp()))
-#  define optind  (*(getoptindp()))
-#  define optopt  (*(getoptoptp()))
-#endif
-
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/
@@ -372,10 +362,7 @@ void    swab(FAR const void *src, FAR void *dest, ssize_t nbytes);
 
 int     getopt(int argc, FAR char * const argv[], FAR const char *optstring);
 
-/* Accessor functions intended for use only by external NXFLAT
+/* Accessor functions associated with getopt(). */
- * modules.  The global variables optarg, optind, and optopt cannot
- * be referenced directly from external modules.
- */
 
 FAR char **getoptargp(void);  /* Optional argument following option */
 FAR int   *getopterrp(void);  /* Print error message */

libs/libc/unistd/Make.defs

@@ -21,8 +21,9 @@
 # Add the unistd C files to the build
 
 CSRCS += lib_access.c lib_daemon.c lib_swab.c lib_pathconf.c lib_sysconf.c
-CSRCS += lib_getopt.c lib_getoptargp.c lib_getopterrp.c lib_getoptindp.c
+CSRCS += lib_getopt.c lib_getoptvars.c lib_getoptargp.c lib_getopterrp.c
-CSRCS += lib_getoptoptp.c lib_alarm.c lib_fstatvfs.c lib_statvfs.c lib_sleep.c
+CSRCS += lib_getoptindp.c lib_getoptoptp.c
+CSRCS += lib_alarm.c lib_fstatvfs.c lib_statvfs.c lib_sleep.c
 CSRCS += lib_usleep.c lib_seteuid.c lib_setegid.c lib_geteuid.c lib_getegid.c
 CSRCS += lib_setreuid.c lib_setregid.c
 CSRCS += lib_getrusage.c lib_utimes.c

libs/libc/unistd/lib_getopt.c

@@ -28,27 +28,16 @@
 #include <getopt.h>
 #include <string.h>
 
+#include "unistd.h"
+
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
 
-/****************************************************************************
+#undef optarg
- * Public Data
+#undef opterr
- ****************************************************************************/
+#undef optind
-
+#undef optopt
-FAR char *optarg; /* Optional argument following option */
-int opterr = 0;   /* Print error message */
-int optind = 1;   /* Index into argv */
-int optopt = '?'; /* unrecognized option character */
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
-static FAR char         *g_optptr       = NULL;
-static FAR char * const *g_argv         = NULL;
-static int               g_argc         = 0;
-static bool              g_binitialized = false;
 
 /****************************************************************************
  * Public Functions
@@ -103,18 +92,12 @@ static bool              g_binitialized = false;
 
 int getopt(int argc, FAR char * const argv[], FAR const char *optstring)
 {
-  /* Were new argc or argv passed in?  This detects misuse of getopt() by
+  /* Get thread-specific getopt() variables */
-   * applications that break out of the getopt() loop before getop() returns
-   * -1.
-   */
 
-  if (argc != g_argc || argv != g_argv)
+  FAR struct getopt_s *go = getoptvars();
+  if (go == NULL)
     {
-      /* Yes, clear the internal state */
+      return '?';
-
-      g_binitialized = false;
-      g_argc         = argc;
-      g_argv         = argv;
     }
 
   /* Verify input parameters. */
@@ -128,13 +111,13 @@ int getopt(int argc, FAR char * const argv[], FAR const char *optstring)
        * the program, optind must be reset to some value <= 1.
        */
 
-      if (optind < 1 || !g_binitialized)
+      if (go->go_optind < 1 || !go->go_binitialized)
         {
-          optarg         = NULL;
+          go->go_optarg       = NULL;
-          optind         = 1;     /* Skip over the program name */
+          go->go_optind       = 1;     /* Skip over the program name */
-          optopt         = '?';
+          go->go_optopt       = '?';
-          g_optptr       = NULL;  /* Start at the beginning of the first argument */
+          go->go_optptr       = NULL;  /* Start at the beginning of the first argument */
-          g_binitialized = true;  /* Now we are initialized */
+          go->go_binitialized = true;  /* Now we are initialized */
         }
 
       /* If the first character of opstring s ':', then ':' is in the event
@@ -148,34 +131,34 @@ int getopt(int argc, FAR char * const argv[], FAR const char *optstring)
         }
 
       /* Are we resuming in the middle, or at the end of a string of
-       * arguments? g_optptr == NULL means that we are started at the
+       * arguments? optptr == NULL means that we are started at the
-       * beginning of argv[optind]; *g_optptr == \0 means that we are
+       * beginning of argv[optind]; *optptr == \0 means that we are
        * starting at the beginning of optind+1
        */
 
-      while (!g_optptr || !*g_optptr)
+      while (!go->go_optptr || !*go->go_optptr)
         {
           /* We need to start at the beginning of the next argv. Check if we
            * need to increment optind
            */
 
-          if (g_optptr)
+          if (go->go_optptr)
             {
               /* Yes.. Increment it and check for the case where where we
                * have processed everything in the argv[] array.
                */
 
-              optind++;
+              go->go_optind++;
             }
 
           /* Check for the end of the argument list */
 
-          g_optptr = argv[optind];
+          go->go_optptr = argv[go->go_optind];
-          if (!g_optptr)
+          if (!go->go_optptr)
             {
               /* There are no more arguments, we are finished */
 
-              g_binitialized = false;
+              go->go_binitialized = false;
               return ERROR;
             }
 
@@ -183,47 +166,47 @@ int getopt(int argc, FAR char * const argv[], FAR const char *optstring)
            * the first character must be '-'
            */
 
-          if (*g_optptr != '-')
+          if (*go->go_optptr != '-')
             {
               /* The argument does not start with '-', we are finished */
 
-              g_binitialized = false;
+              go->go_binitialized = false;
               return ERROR;
             }
 
           /* Skip over the '-' */
 
-          g_optptr++;
+          go->go_optptr++;
         }
 
       /* Special case handling of "-" and "-:" */
 
-      if (!*g_optptr)
+      if (!*go->go_optptr)
         {
-          optopt = '\0'; /* We'll fix up g_optptr the next time we are called */
+          go->go_optopt = '\0'; /* We'll fix up optptr the next time we are called */
           return '?';
         }
 
       /* Handle the case of "-:" */
 
-      if (*g_optptr == ':')
+      if (*go->go_optptr == ':')
         {
-          optopt = ':';
+          go->go_optopt = ':';
-          g_optptr++;
+          go->go_optptr++;
           return '?';
         }
 
-      /* g_optptr now points at the next option and it is not something
+      /* go->go_optptr now points at the next option and it is not something
        * crazy. check if the option is in the list of valid options.
        */
 
-      optchar = strchr(optstring, *g_optptr);
+      optchar = strchr(optstring, *go->go_optptr);
       if (!optchar)
         {
           /* No this character is not in the list of valid options */
 
-          optopt = *g_optptr;
+          go->go_optopt = *go->go_optptr;
-          g_optptr++;
+          go->go_optptr++;
           return '?';
         }
 
@@ -235,7 +218,7 @@ int getopt(int argc, FAR char * const argv[], FAR const char *optstring)
         {
           /* No, no arguments. Just return the character that we found */
 
-          g_optptr++;
+          go->go_optptr++;
           return *optchar;
         }
 
@@ -243,40 +226,40 @@ int getopt(int argc, FAR char * const argv[], FAR const char *optstring)
        * immediately after the command in this same argument?
        */
 
-      if (g_optptr[1] != '\0')
+      if (go->go_optptr[1] != '\0')
         {
           /* Yes, return a pointer into the current argument */
 
-          optarg = &g_optptr[1];
+          go->go_optarg = &go->go_optptr[1];
-          optind++;
+          go->go_optind++;
-          g_optptr = NULL;
+          go->go_optptr = NULL;
           return *optchar;
         }
 
       /* No.. is the optional argument the next argument in argv[] ? */
 
-      if (argv[optind + 1] && *argv[optind + 1] != '-')
+      if (argv[go->go_optind + 1] && *argv[go->go_optind + 1] != '-')
         {
           /* Yes.. return that */
 
-          optarg = argv[optind + 1];
+          go->go_optarg = argv[go->go_optind + 1];
-          optind += 2;
+          go->go_optind += 2;
-          g_optptr = NULL;
+          go->go_optptr = NULL;
           return *optchar;
         }
 
       /* No argument was supplied */
 
-      g_optptr = NULL;
+      go->go_optptr = NULL;
-      optarg   = NULL;
+      go->go_optarg = NULL;
-      optopt   = *optchar;
+      go->go_optopt = *optchar;
-      optind++;
+      go->go_optind++;
       return noarg_ret;
     }
 
   /* Restore the initial, uninitialized state */
 
-  g_binitialized = false;
+  go->go_binitialized = false;
   return ERROR;
 }
 

libs/libc/unistd/lib_getoptargp.c

@@ -26,17 +26,7 @@
 
 #include <unistd.h>
 
-/****************************************************************************
+#include "unistd.h"
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Public Data
- ****************************************************************************/
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
 
 /****************************************************************************
  * Public Functions
@@ -53,5 +43,6 @@
 
 FAR char **getoptargp(void)
 {
-  return &optarg;
+  FAR struct getopt_s *go = getoptvars();
+  return &go->go_optarg;
 }

libs/libc/unistd/lib_getopterrp.c

@@ -26,6 +26,8 @@
 
 #include <unistd.h>
 
+#include "unistd.h"
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -41,5 +43,6 @@
 
 FAR int *getopterrp(void)
 {
-  return &opterr;
+  FAR struct getopt_s *go = getoptvars();
+  return &go->go_opterr;
 }

libs/libc/unistd/lib_getoptindp.c

@@ -26,17 +26,7 @@
 
 #include <unistd.h>
 
-/****************************************************************************
+#include "unistd.h"
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Public Data
- ****************************************************************************/
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
 
 /****************************************************************************
  * Public Functions
@@ -53,5 +43,6 @@
 
 int *getoptindp(void)
 {
-  return &optind;
+  FAR struct getopt_s *go = getoptvars();
+  return &go->go_optind;
 }

libs/libc/unistd/lib_getoptoptp.c

@@ -26,17 +26,7 @@
 
 #include <unistd.h>
 
-/****************************************************************************
+#include "unistd.h"
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Public Data
- ****************************************************************************/
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
 
 /****************************************************************************
  * Public Functions
@@ -53,5 +43,6 @@
 
 int *getoptoptp(void)
 {
-  return &optopt;
+  FAR struct getopt_s *go = getoptvars();
+  return &go->go_optopt;
 }

libs/libc/unistd/lib_getoptvars.c

@@ -0,0 +1,83 @@
+/****************************************************************************
+ * libs/libc/unistd/lib_getoptvars.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <unistd.h>
+#include <assert.h>
+
+#include <nuttx/tls.h>
+#include <nuttx/lib/libvars.h>
+
+#include <arch/tls.h>
+
+#include "unistd.h"
+#include "libc.h"
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+#ifdef CONFIG_BUILD_KERNEL
+/* Data is naturally process-specific in the KERNEL build so no special
+ * access to process-specific global data is needed.
+ */
+
+FAR struct getopt_s g_getopt_vars =
+{
+  NULL,
+  0,
+  1,
+  '?',
+  NULL,
+  false
+};
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: getoptvars
+ *
+ * Description:
+ *   Returns a pointer to to the thread-specific getopt() data.
+ *
+ ****************************************************************************/
+
+FAR struct getopt_s *getoptvars(void)
+{
+#ifndef CONFIG_BUILD_KERNEL
+  FAR struct tls_info_s *tlsinfo;
+
+  /* Get the structure of getopt() variables using the key. */
+
+  tlsinfo = up_tls_info();
+  DEBUGASSERT(tlsinfo != NULL && tlsinfo->tl_libvars != NULL);
+  return &tlsinfo->tl_libvars->lv_getopt;
+#else
+  return &g_getopt_vars;
+#endif
+}

libs/libc/unistd/unistd.h

@@ -0,0 +1,66 @@
+/****************************************************************************
+ * libs/libc/unistd/unistd.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __LIBC_UNISTD_UNISTD_H
+#define __LIBC_UNISTD_UNISTD_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdbool.h>
+
+#include <nuttx/lib/getopt.h>
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: getoptvars
+ *
+ * Description:
+ *   Returns a pointer to to the thread-specific getopt() data.
+ *
+ ****************************************************************************/
+
+FAR struct getopt_s *getoptvars(void);
+
+#undef EXTERN
+#if defined(__cplusplus)
+}
+#endif
+
+#endif /* __LIBC_UNISTD_UNISTD_H */

sched/group/Make.defs

@@ -57,6 +57,10 @@ ifneq ($(CONFIG_TLS_NELEM),0)
 CSRCS += group_tlsalloc.c group_tlsfree.c
 endif
 
+ifndef CONFIG_BUILD_KERNEL
+CSRCS += group_taskdata.c
+endif
+
 # Include group build support
 
 DEPPATH += --dep-path group

sched/group/group.h

@@ -140,4 +140,10 @@ int  group_setuptaskfiles(FAR struct task_tcb_s *tcb);
 int  group_setupstreams(FAR struct task_tcb_s *tcb);
 #endif
 
+#ifndef CONFIG_BUILD_KERNEL
+/* Task specific data */
+
+void tls_set_taskdata(FAR struct tcb_s *tcb);
+#endif
+
 #endif /* __SCHED_GROUP_GROUP_H */

sched/group/group_taskdata.c

@@ -0,0 +1,75 @@
+/****************************************************************************
+ * sched/group/group_taskdata.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <assert.h>
+
+#include <nuttx/tls.h>
+
+#include "group/group.h"
+
+#ifndef CONFIG_BUILD_KERNEL
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: tls_set_taskdata
+ *
+ * Description:
+ *   Set task-specific data pointer in TLS.
+ *
+ * Input Parameters:
+ *   tcb - Identifies task to set TLS data
+ *
+ * Returned Value:
+ *   None
+ *
+ ****************************************************************************/
+
+void tls_set_taskdata(FAR struct tcb_s *tcb)
+{
+  FAR struct tls_info_s *info;
+  FAR struct task_group_s *group;
+
+  DEBUGASSERT(tcb != NULL && tcb->group != NULL);
+  group = tcb->group;
+
+  /* This currently assumes a push-down stack.  The TLS data lies at the
+   * lowest address of the stack allocation.
+   */
+
+  info = (FAR struct tls_info_s *)tcb->stack_alloc_ptr;
+
+  /* Copy the task data point buffer in the group structure into the
+   * thread's TLS data.
+   */
+
+  info->tl_libvars = group->tg_libvars;
+}
+
+#endif /* !CONFIG_BUILD_KERNEL */

sched/pthread/pthread_create.c

@@ -301,6 +301,12 @@ int pthread_create(FAR pthread_t *thread, FAR const pthread_attr_t *attr,
       goto errout_with_join;
     }
 
+#ifndef CONFIG_BUILD_KERNEL
+  /* Save the allocated task data in TLS */
+
+  tls_set_taskdata(&ptcb->cmn);
+#endif
+
   /* Should we use the priority and scheduler specified in the pthread
    * attributes?  Or should we use the current thread's priority and
    * scheduler?

sched/task/task_init.c

@@ -32,6 +32,7 @@
 
 #include <nuttx/arch.h>
 #include <nuttx/sched.h>
+#include <nuttx/lib/libvars.h>
 
 #include "sched/sched.h"
 #include "group/group.h"
@@ -84,11 +85,14 @@ int nxtask_init(FAR struct task_tcb_s *tcb, const char *name, int priority,
                 main_t entry, FAR char * const argv[])
 {
   uint8_t ttype = tcb->cmn.flags & TCB_FLAG_TTYPE_MASK;
+#ifndef CONFIG_BUILD_KERNEL
+  FAR struct task_group_s *group;
+#endif
   int ret;
 
+#ifndef CONFIG_DISABLE_PTHREAD
   /* Only tasks and kernel threads can be initialized in this way */
 
-#ifndef CONFIG_DISABLE_PTHREAD
   DEBUGASSERT(tcb && ttype != TCB_FLAG_TTYPE_PTHREAD);
 #endif
 
@@ -126,6 +130,18 @@ int nxtask_init(FAR struct task_tcb_s *tcb, const char *name, int priority,
       goto errout_with_group;
     }
 
+#ifndef CONFIG_BUILD_KERNEL
+  /* Allocate a stack frame to hold task-specific data */
+
+  group = tcb->cmn.group;
+  group->tg_libvars = up_stack_frame(&tcb->cmn, sizeof(struct libvars_s));
+  DEBUGASSERT(group->tg_libvars != NULL);
+
+  /* Save the allocated task data in TLS */
+
+  tls_set_taskdata(&tcb->cmn);
+#endif
+
   /* Initialize the task control block */
 
   ret = nxtask_setup_scheduler(tcb, priority, nxtask_start,