NSH: Add support for the 'ln' command.

nshlib/Kconfig

@@ -316,6 +316,11 @@ config NSH_DISABLE_LOSMART
 	default y if DEFAULT_SMALL || !MTD_SMART
 	default n if !DEFAULT_SMALL && MTD_SMART
 
+config NSH_DISABLE_LN
+	bool "Disable ln"
+	default n
+	depends on PSEUDOFS_SOFTLINKS
+
 config NSH_DISABLE_LS
 	bool "Disable ls"
 	default n

nshlib/README.txt

@@ -613,6 +613,19 @@ o losetup [-d <dev-path>] | [[-o <offset>] [-r] <ldev-path> <file-path>]
     This is a test
     nsh>
 
+o ln [-s] <target> <link>
+
+  The link command will create a new symbolic link at <link> for the
+  existing file or directory, <target>.  This implementation is simplied
+  for use with NuttX in these ways:
+
+    - Links may be created only within the NuttX top-level, pseudo file
+      system.  No file system currently supported by NuttX provides
+      symbolic links.
+    - For the same reason, only soft links are implemented.
+    - File privileges are ignored.
+    - c_time is not updated.
+
 o ls [-lRs] <dir-path>
 
   Show the contents of the directory at <dir-path>.  NOTE:
@@ -1195,6 +1208,7 @@ Command Dependencies on Configuration Settings
   insmod     CONFIG_MODULE
   kill       !CONFIG_DISABLE_SIGNALS
   losetup    !CONFIG_DISABLE_MOUNTPOINT && CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_DEV_LOOP
+  ln         CONFIG_NFILE_DESCRIPTORS > 0 && CONFIG_PSEUDOFS_SOFTLINK
   ls         CONFIG_NFILE_DESCRIPTORS > 0
   lsmod      CONFIG_MODULE && CONFIG_FS_PROCFS && !CONFIG_FS_PROCFS_EXCLUDE_MODULE
   md5        CONFIG_NETUTILS_CODECS && CONFIG_CODECS_HASH_MD5
@@ -1257,20 +1271,20 @@ also allow it to squeeze into very small memory footprints.
   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_LS,        CONFIG_NSH_DISABLE_MD5,
+  CONFIG_NSH_DISABLE_LOSETUP,   CONFIG_NSH_DISABLE_LN,        CONFIG_NSH_DISABLE_LS,
-  CONFIG_NSH_DISABLE_MB,        CONFIG_NSH_DISABLE_MKDIR,     CONFIG_NSH_DISABLE_MKFATFS,
+  CONFIG_NSH_DISABLE_MD5,       CONFIG_NSH_DISABLE_MB,        CONFIG_NSH_DISABLE_MKDIR,
-  CONFIG_NSH_DISABLE_MKFIFO,    CONFIG_NSH_DISABLE_MKRD,      CONFIG_NSH_DISABLE_MH,
+  CONFIG_NSH_DISABLE_MKFATFS,   CONFIG_NSH_DISABLE_MKFIFO,    CONFIG_NSH_DISABLE_MKRD,
-  CONFIG_NSH_DISABLE_MODCMDS,   CONFIG_NSH_DISABLE_MOUNT,     CONFIG_NSH_DISABLE_MW,
+  CONFIG_NSH_DISABLE_MH,        CONFIG_NSH_DISABLE_MODCMDS,   CONFIG_NSH_DISABLE_MOUNT,
-  CONFIG_NSH_DISABLE_MV,        CONFIG_NSH_DISABLE_NFSMOUNT,  CONFIG_NSH_DISABLE_NSLOOKUP,
+  CONFIG_NSH_DISABLE_MW,        CONFIG_NSH_DISABLE_MV,        CONFIG_NSH_DISABLE_NFSMOUNT,
-  CONFIG_NSH_DISABLE_PASSWD,    CONFIG_NSH_DISABLE_PING,      CONFIG_NSH_DISABLE_PING6,
+  CONFIG_NSH_DISABLE_NSLOOKUP,  CONFIG_NSH_DISABLE_PASSWD,    CONFIG_NSH_DISABLE_PING,
-  CONFIG_NSH_DISABLE_POWEROFF,  CONFIG_NSH_DISABLE_PS,        CONFIG_NSH_DISABLE_PUT,
+  CONFIG_NSH_DISABLE_PING6,     CONFIG_NSH_DISABLE_POWEROFF,  CONFIG_NSH_DISABLE_PS,
-  CONFIG_NSH_DISABLE_PWD,       CONFIG_NSH_DISABLE_REBOOT,    CONFIG_NSH_DISABLE_RM,
+  CONFIG_NSH_DISABLE_PUT,       CONFIG_NSH_DISABLE_PWD,       CONFIG_NSH_DISABLE_REBOOT,
-  CONFIG_NSH_DISABLE_RMDIR,     CONFIG_NSH_DISABLE_SET,       CONFIG_NSH_DISABLE_SH,
+  CONFIG_NSH_DISABLE_RM,        CONFIG_NSH_DISABLE_RMDIR,     CONFIG_NSH_DISABLE_SET,
-  CONFIG_NSH_DISABLE_SHUTDOWN,  CONFIG_NSH_DISABLE_SLEEP,     CONFIG_NSH_DISABLE_TEST,
+  CONFIG_NSH_DISABLE_SH,        CONFIG_NSH_DISABLE_SHUTDOWN,  CONFIG_NSH_DISABLE_SLEEP,
-  CONFIG_NSH_DIABLE_TIME,       CONFIG_NSH_DISABLE_UMOUNT,    CONFIG_NSH_DISABLE_UNSET,
+  CONFIG_NSH_DISABLE_TEST,      CONFIG_NSH_DIABLE_TIME,       CONFIG_NSH_DISABLE_UMOUNT,
-  CONFIG_NSH_DISABLE_URLDECODE, CONFIG_NSH_DISABLE_URLENCODE, CONFIG_NSH_DISABLE_USERADD,
+  CONFIG_NSH_DISABLE_UNSET,     CONFIG_NSH_DISABLE_URLDECODE, CONFIG_NSH_DISABLE_URLENCODE,
-  CONFIG_NSH_DISABLE_USERDEL,   CONFIG_NSH_DISABLE_USLEEP,    CONFIG_NSH_DISABLE_WGET,
+  CONFIG_NSH_DISABLE_USERADD,   CONFIG_NSH_DISABLE_USERDEL,   CONFIG_NSH_DISABLE_USLEEP,
-  CONFIG_NSH_DISABLE_XD
+  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

@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh.h
  *
- *   Copyright (C) 2007-2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -1008,6 +1008,9 @@ int cmd_lsmod(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #  ifndef CONFIG_NSH_DISABLE_HEXDUMP
       int cmd_hexdump(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #   endif
+#  if !defined(CONFIG_NSH_DISABLE_LN) && defined(CONFIG_PSEUDOFS_SOFTLINKS)
+      int cmd_ln(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
+#  endif
 #  ifndef CONFIG_NSH_DISABLE_LS
       int cmd_ls(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv);
 #  endif

nshlib/nsh_command.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh_command.c
  *
- *   Copyright (C) 2007-2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -270,6 +270,12 @@ static const struct cmdmap_s g_cmdmap[] =
 # endif
 #endif
 
+#if CONFIG_NFILE_DESCRIPTORS > 0
+#  if !defined(CONFIG_NSH_DISABLE_LN) && defined(CONFIG_PSEUDOFS_SOFTLINKS)
+  { "ln",       cmd_ln,       3, 4, "[-s] <target> <link>" },
+# endif
+#endif
+
 #if CONFIG_NFILE_DESCRIPTORS > 0
 # ifndef CONFIG_NSH_DISABLE_LS
   { "ls",       cmd_ls,       1, 5, "[-lRs] <dir-path>" },

nshlib/nsh_fscmds.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * apps/nshlib/nsh_fscmds.c
  *
- *   Copyright (C) 2007-2009, 2011-2014 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011-2014, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -936,6 +936,59 @@ errout_with_paths:
 #endif
 #endif
 
+/****************************************************************************
+ * Name: cmd_ln
+ ****************************************************************************/
+
+#if CONFIG_NFILE_DESCRIPTORS > 0
+#  if !defined(CONFIG_NSH_DISABLE_LN) && defined(CONFIG_PSEUDOFS_SOFTLINKS)
+int cmd_ln(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
+{
+  FAR char *fullpath;
+  FAR char *target;
+  int ndx;
+  int ret;
+
+  /* ln [-s] <target> <link> */
+
+  if (argc == 4)
+    {
+      if (strcmp(argv[1], "-s") != 0)
+        {
+          nsh_output(vtbl, g_fmtarginvalid, argv[0]);
+          return ERROR;
+        }
+
+      ndx = 2;
+    }
+  else
+    {
+      ndx = 1;
+    }
+
+  /* Get the fullpath to the directory */
+
+  target   = argv[ndx];
+  fullpath = nsh_getfullpath(vtbl, argv[ndx + 1]);
+
+  if (!fullpath)
+    {
+      return ERROR;
+    }
+
+  ret = link(target, fullpath);
+  if (ret < 0)
+    {
+      nsh_output(vtbl, g_fmtcmdfailed, argv[0], "link", NSH_ERRNO);
+      return ERROR;
+    }
+
+  nsh_freefullpath(fullpath);
+  return ret;
+}
+#endif
+#endif
+
 /****************************************************************************
  * Name: cmd_ls
  ****************************************************************************/
@@ -945,9 +998,9 @@ errout_with_paths:
 int cmd_ls(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 {
   struct stat st;
-  const char *relpath;
+  FAR const char *relpath;
   unsigned int lsflags = 0;
-  char *fullpath;
+  FAR char *fullpath;
   bool badarg = false;
   int len;
   int ret;
@@ -1083,6 +1136,7 @@ int cmd_mkdir(FAR struct nsh_vtbl_s *vtbl, int argc, char **argv)
 
       nsh_freefullpath(fullpath);
     }
+
   return ret;
 }
 #endif