apps/nshlib: Add support for the 'env' command.

nshlib/Kconfig

@@ -284,6 +284,10 @@ config NSH_DISABLE_ECHO
 	bool "Disable echo"
 	default n
 
+config NSH_DISABLE_ENV
+	bool "Disable env"
+	default n
+
 config NSH_DISABLE_EXEC
 	bool "Disable exec"
 	default y if DEFAULT_SMALL

nshlib/README.txt

@@ -481,6 +481,25 @@ o echo [-n] [<string|$name> [<string|$name>...]]
 
   The -n option will suppress the trailing newline character.
 
+o env
+
+  Show the current address environment.  Example:
+
+  nsh> env
+  PATH=/bin
+
+  nsh> set foo bar
+  nsh> env
+  PATH=/bin
+  foo=bar
+
+  nsh> unset PATH
+  nsh> env
+  env
+  foo=bar
+
+  nsh>
+
 o exec <hex-address>
 
   Execute the user logic at address <hex-address>.  NSH will pause
@@ -1347,6 +1366,7 @@ Command Dependencies on Configuration Settings
   df         !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_READABLE (see note 3)
   dirname    --
   echo       --
+  env        -- CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_FS_PROCFS && !CONFIG_DISABLE_ENVIRON && !CONFIG_PROCFS_EXCLUDE_ENVIRON
   exec       --
   exit       --
   free       --
@@ -1424,24 +1444,24 @@ also allow it to squeeze into very small memory footprints.
   CONFIG_NSH_DISABLE_BASENAME,  CONFIG_NSH_DISABLE_CAT,       CONFIG_NSH_DISABLE_CD,
   CONFIG_NSH_DISABLE_CP,        CONFIG_NSH_DISABLE_DD,        CONFIG_NSH_DISABLE_DELROUTE,
   CONFIG_NSH_DISABLE_DF,        CONFIG_NSH_DISABLE_DIRNAME,   CONFIG_NSH_DISABLE_ECHO,
-  CONFIG_NSH_DISABLE_EXEC,      CONFIG_NSH_DISABLE_EXIT,      CONFIG_NSH_DISABLE_FREE,
-  CONFIG_NSH_DISABLE_GET,       CONFIG_NSH_DISABLE_HELP,      CONFIG_NSH_DISABLE_HEXDUMP,
-  CONFIG_NSH_DISABLE_IFCONFIG,  CONFIG_NSH_DISABLE_IFUPDOWN,  CONFIG_NSH_DISABLE_KILL,
-  CONFIG_NSH_DISABLE_LOSETUP,   CONFIG_NSH_DISABLE_LN,        CONFIG_NSH_DISABLE_LS,
-  CONFIG_NSH_DISABLE_MD5,       CONFIG_NSH_DISABLE_MB,        CONFIG_NSH_DISABLE_MKDIR,
-  CONFIG_NSH_DISABLE_MKFATFS,   CONFIG_NSH_DISABLE_MKFIFO,    CONFIG_NSH_DISABLE_MKRD,
-  CONFIG_NSH_DISABLE_MH,        CONFIG_NSH_DISABLE_MODCMDS,   CONFIG_NSH_DISABLE_MOUNT,
-  CONFIG_NSH_DISABLE_MW,        CONFIG_NSH_DISABLE_MV,        CONFIG_NSH_DISABLE_NFSMOUNT,
-  CONFIG_NSH_DISABLE_NSLOOKUP,  CONFIG_NSH_DISABLE_PASSWD,    CONFIG_NSH_DISABLE_PING6,
-  CONFIG_NSH_DISABLE_POWEROFF,  CONFIG_NSH_DISABLE_PS,        CONFIG_NSH_DISABLE_PUT,
-  CONFIG_NSH_DISABLE_PWD,       CONFIG_NSH_DISABLE_READLINK,  CONFIG_NSH_DISABLE_REBOOT,
-  CONFIG_NSH_DISABLE_RM,        CONFIG_NSH_DISABLE_RMDIR,     CONFIG_NSH_DISABLE_ROUTE,
-  CONFIG_NSH_DISABLE_SET,       CONFIG_NSH_DISABLE_SH,        CONFIG_NSH_DISABLE_SHUTDOWN,
-  CONFIG_NSH_DISABLE_SLEEP,     CONFIG_NSH_DISABLE_TEST,      CONFIG_NSH_DIABLE_TIME,
-  CONFIG_NSH_DISABLE_TRUNCATE,  CONFIG_NSH_DISABLE_UMOUNT,    CONFIG_NSH_DISABLE_UNSET,
-  CONFIG_NSH_DISABLE_URLDECODE, CONFIG_NSH_DISABLE_URLENCODE, CONFIG_NSH_DISABLE_USERADD,
-  CONFIG_NSH_DISABLE_USERDEL,   CONFIG_NSH_DISABLE_USLEEP,    CONFIG_NSH_DISABLE_WGET,
-  CONFIG_NSH_DISABLE_XD
+  CONFIG_NSH_DISABLE_ENV,       CONFIG_NSH_DISABLE_EXEC,      CONFIG_NSH_DISABLE_EXIT,
+  CONFIG_NSH_DISABLE_FREE,      CONFIG_NSH_DISABLE_GET,       CONFIG_NSH_DISABLE_HELP,
+  CONFIG_NSH_DISABLE_HEXDUMP,   CONFIG_NSH_DISABLE_IFCONFIG,  CONFIG_NSH_DISABLE_IFUPDOWN,
+  CONFIG_NSH_DISABLE_KILL,      CONFIG_NSH_DISABLE_LOSETUP,   CONFIG_NSH_DISABLE_LN,
+  CONFIG_NSH_DISABLE_LS,        CONFIG_NSH_DISABLE_MD5,       CONFIG_NSH_DISABLE_MB,
+  CONFIG_NSH_DISABLE_MKDIR,     CONFIG_NSH_DISABLE_MKFATFS,   CONFIG_NSH_DISABLE_MKFIFO,
+  CONFIG_NSH_DISABLE_MKRD,      CONFIG_NSH_DISABLE_MH,        CONFIG_NSH_DISABLE_MODCMDS,
+  CONFIG_NSH_DISABLE_MOUNT,     CONFIG_NSH_DISABLE_MW,        CONFIG_NSH_DISABLE_MV,
+  CONFIG_NSH_DISABLE_NFSMOUNT,  CONFIG_NSH_DISABLE_NSLOOKUP,  CONFIG_NSH_DISABLE_PASSWD,
+  CONFIG_NSH_DISABLE_PING6,     CONFIG_NSH_DISABLE_POWEROFF,  CONFIG_NSH_DISABLE_PS,
+  CONFIG_NSH_DISABLE_PUT,       CONFIG_NSH_DISABLE_PWD,       CONFIG_NSH_DISABLE_READLINK,
+  CONFIG_NSH_DISABLE_REBOOT,    CONFIG_NSH_DISABLE_RM,        CONFIG_NSH_DISABLE_RMDIR,
+  CONFIG_NSH_DISABLE_ROUTE,     CONFIG_NSH_DISABLE_SET,       CONFIG_NSH_DISABLE_SH,
+  CONFIG_NSH_DISABLE_SHUTDOWN,  CONFIG_NSH_DISABLE_SLEEP,     CONFIG_NSH_DISABLE_TEST,
+  CONFIG_NSH_DIABLE_TIME,       CONFIG_NSH_DISABLE_TRUNCATE,  CONFIG_NSH_DISABLE_UMOUNT,
+  CONFIG_NSH_DISABLE_UNSET,     CONFIG_NSH_DISABLE_URLDECODE, CONFIG_NSH_DISABLE_URLENCODE,
+  CONFIG_NSH_DISABLE_USERADD,   CONFIG_NSH_DISABLE_USERDEL,   CONFIG_NSH_DISABLE_USLEEP,
+  CONFIG_NSH_DISABLE_WGET,      CONFIG_NSH_DISABLE_XD
 
 Verbose help output can be suppressed by defining CONFIG_NSH_HELP_TERSE.  In that
 case, the help command is still available but will be slightly smaller.

nshlib/nsh.h

@@ -677,14 +677,20 @@
 #  undef NSH_HAVE_TRIMDIR
 #endif
 
-/* nsh_catfile used by cat, ifconfig, ifup/down, df, free, irqinfo, and mount (with
- * no arguments).
+#if !defined(CONFIG_FS_PROCFS) || defined(CONFIG_DISABLE_ENVIRON) || \
+     defined(CONFIG_FS_PROCFS_EXCLUDE_ENVIRON) || !defined(NSH_HAVE_CATFILE)
+#  undef CONFIG_NSH_DISABLE_ENV
+#  define CONFIG_NSH_DISABLE_ENV 1
+#endif
+
+/* nsh_catfile used by cat, ifconfig, ifup/down, df, free, env, irqinfo, and
+ * mount (with no arguments).
  */
 
 #if !defined(CONFIG_NSH_DISABLE_CAT) && !defined(CONFIG_NSH_DISABLE_IFCONFIG) && \
     !defined(CONFIG_NSH_DISABLE_IFUPDOWN) && !defined(CONFIG_NSH_DISABLE_DF) && \
-    !defined(CONFIG_NSH_DISABLE_FREE) && !defined(HAVE_IRQINFO) && \
-    !defined(HAVE_MOUNT_LIST)
+    !defined(CONFIG_NSH_DISABLE_FREE) && !defined(CONFIG_NSH_DISABLE_ENV) && \
+    !defined(HAVE_IRQINFO) && !defined(HAVE_MOUNT_LIST)
 #  undef NSH_HAVE_CATFILE
 #endif
 
@@ -1166,6 +1172,10 @@ int cmd_irqinfo(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 # endif /* !CONFIG_DISABLE_MOUNTPOINT */
 #endif /* CONFIG_NFILE_DESCRIPTORS */
 
+#ifndef CONFIG_NSH_DISABLE_ENV
+int cmd_env(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#endif
+
 #if defined(CONFIG_NET)
 #  if defined(CONFIG_NET_ARP) && !defined(CONFIG_NSH_DISABLE_ARP)
       int cmd_arp(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);

nshlib/nsh_command.c

@@ -192,6 +192,10 @@ static const struct cmdmap_s g_cmdmap[] =
 # endif
 #endif
 
+#ifndef CONFIG_NSH_DISABLE_ENV
+  { "env",      cmd_env,      1, 1, NULL },
+#endif
+
 #ifndef CONFIG_NSH_DISABLE_EXEC
   { "exec",     cmd_exec,     2, 3, "<hex-address>" },
 #endif

nshlib/nsh_envcmds.c

@@ -292,6 +292,18 @@ int cmd_echo(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 }
 #endif
 
+/****************************************************************************
+ * Name: cmd_env
+ ****************************************************************************/
+
+#ifndef CONFIG_NSH_DISABLE_ENV
+int cmd_env(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  return nsh_catfile(vtbl, argv[0],
+                     CONFIG_NSH_PROC_MOUNTPOINT "/self/group/env");
+}
+#endif
+
 /****************************************************************************
  * Name: cmd_pwd
  ****************************************************************************/