nshlib: support dd with conv=notrunc,nocreat

refs to: https://man7.org/linux/man-pages/man1/dd.1.html

Signed-off-by: dongjiuzhu1 <[email protected]>

Author: Donny9

nshlib/nsh_command.c

@@ -188,7 +188,7 @@ static const struct cmdmap_s g_cmdmap[] =
 #ifndef CONFIG_NSH_DISABLE_DD
   CMD_MAP("dd",       cmd_dd,       3, 7,
     "if=<infile> of=<outfile> [bs=<sectsize>] [count=<sectors>] "
-    "[skip=<sectors>] [seek=<sectors>] [verify]"),
+    "[skip=<sectors>] [seek=<sectors>] [verify] [conv=<nocreat,notrunc>]"),
 #endif
 
 #if defined(CONFIG_NET) && defined(CONFIG_NET_ROUTE) && !defined(CONFIG_NSH_DISABLE_DELROUTE)

nshlib/nsh_ddcmd.c

@@ -76,8 +76,8 @@ struct dd_s
   uint32_t     nsectors;   /* Number of sectors to transfer */
   uint32_t     skip;       /* The number of sectors skipped on input */
   uint32_t     seek;       /* The number of bytes skipped on output */
+  int          oflags;     /* The open flags on output deivce */
   bool         eof;        /* true: The end of the input or output file has been hit */
-  bool         verify;     /* true: Verify infile and outfile correctness */
   size_t       sectsize;   /* Size of one sector */
   size_t       nbytes;     /* Number of valid bytes in the buffer */
   FAR uint8_t *buffer;     /* Buffer of data to write to the output file */
@@ -170,8 +170,7 @@ static inline int dd_infopen(FAR const char *name, FAR struct dd_s *dd)
 
 static inline int dd_outfopen(FAR const char *name, FAR struct dd_s *dd)
 {
-  dd->outfd = open(name, (dd->verify ? O_RDWR : O_WRONLY) |
-                          O_CREAT | O_TRUNC, 0644);
+  dd->outfd = open(name, dd->oflags, 0644);
   if (dd->outfd < 0)
     {
       FAR struct nsh_vtbl_s *vtbl = dd->vtbl;
@@ -282,6 +281,7 @@ int cmd_dd(FAR struct nsh_vtbl_s *vtbl, int argc, FAR char **argv)
   dd.vtbl      = vtbl;              /* For nsh_output */
   dd.sectsize  = DEFAULT_SECTSIZE;  /* Sector size if 'bs=' not provided */
   dd.nsectors  = 0xffffffff;        /* MAX_UINT32 */
+  dd.oflags    = O_WRONLY | O_CREAT | O_TRUNC;
 
   /* If no IF= option is provided on the command line, then read
    * from stdin.
@@ -339,7 +339,18 @@ int cmd_dd(FAR struct nsh_vtbl_s *vtbl, int argc, FAR char **argv)
         }
       else if (strncmp(argv[i], "verify", 6) == 0)
         {
-          dd.verify = true;
+          dd.oflags |= O_RDONLY;
+        }
+      else if (strncmp(argv[i], "conv=", 5) == 0)
+        {
+          if (strstr(argv[i], "nocreat") != NULL)
+            {
+              dd.oflags &= ~(O_CREAT | O_TRUNC);
+            }
+          else if (strstr(argv[i], "notrunc") != NULL)
+            {
+              dd.oflags &= ~O_TRUNC;
+            }
         }
     }
 
@@ -450,7 +461,7 @@ int cmd_dd(FAR struct nsh_vtbl_s *vtbl, int argc, FAR char **argv)
              / ((double)elapsed / USEC_PER_SEC)));
 #endif
 
-  if (ret == 0 && dd.verify)
+  if (ret == 0 && (dd.oflags & O_RDONLY) != 0)
     {
       ret = dd_verify(infile, outfile, &dd);
     }