nsh: env variables expansion

1 files changed, 164 insertions, 0 deletions

diff --git a/apps/nshlib/nsh_parse.c b/apps/nshlib/nsh_parse.c
index 3f17149f5..6fd7c04cc 100644
--- a/apps/nshlib/nsh_parse.c
+++ b/apps/nshlib/nsh_parse.c
@@ -1311,6 +1311,140 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 #endif
   vtbl->np.np_redirect = false;
 
+#ifndef CONFIG_DISABLE_ENVIRON
+  /* Expand environment variables before parsing the line */
+
+  FAR char *cmdline_exp = NULL;
+  bool do_expand = false;
+  char *src_ptr = cmdline;
+  unsigned int res_size = 0;
+  char *var_name_start = NULL;
+  char *var_name_end;
+  bool bracket = false;
+
+  while (true) {
+    char c = *src_ptr++;
+    if (var_name_start) {
+      /* Parsing variable name */
+      if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '_') {
+        /* Valid variable char */
+        continue;
+      } else {
+        /* Not valid variable char */
+        if (src_ptr - var_name_start == 1) {
+          /* Empty, it was not a variable */
+          res_size++;
+          var_name_start = NULL;
+        } else {
+          /* End of variable name */
+          if (bracket == (c != '}')) {
+            /* Bad substitution */
+            goto errout;
+          }
+          do_expand = true;
+          var_name_end = src_ptr - 1;
+          char tmp_char = *var_name_end;
+          *var_name_end = '\0';
+          char *var_value = getenv(var_name_start);
+          *var_name_end = tmp_char;
+          res_size += strlen(var_value);
+          var_name_start = NULL;
+          if (c == '}') {
+            bracket = false;
+            continue;
+          }
+        }
+      }
+    }
+    if (c == '$') {
+      /* Start parsing variable */
+      if (*src_ptr == '{') {
+        bracket = true;
+        src_ptr++;
+      }
+      var_name_start = src_ptr;
+      continue;
+    }
+    /* Normal char */
+    res_size++;
+    if (c == '\0')
+      break;
+  }
+  if (do_expand) {
+    /* Second pass: allocate buffer and expand command line */
+
+    printf("Orig: %s", cmdline);
+    printf("Expand, size: %d\n", res_size);
+
+    cmdline_exp = (char*) malloc(res_size);
+
+    src_ptr = cmdline;
+    char *res_ptr = cmdline_exp;
+    var_name_start = NULL;
+
+    while (true) {
+      char c = *src_ptr++;
+      if (var_name_start) {
+        /* Parsing variable name */
+        if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || c == '_') {
+          /* Valid variable char */
+          continue;
+        } else {
+          /* Not valid variable char */
+          if (src_ptr - var_name_start == 1) {
+            /* Empty, it was not a variable */
+            *res_ptr++ = *(src_ptr - 1);
+            var_name_start = NULL;
+          } else {
+            /* End of variable name */
+            if (bracket == (c != '}')) {
+              /* Bad substitution */
+              goto errout;
+            }
+            do_expand = true;
+            var_name_end = src_ptr - 1;
+            char tmp_char = *var_name_end;
+            *var_name_end = '\0';
+            char *var_value = getenv(var_name_start);
+            printf("VAR: %s = %s\n", var_name_start, var_value);
+            *var_name_end = tmp_char;
+            //res_ptr = stpcpy(res_ptr, var_value);
+            if (var_value) {
+				for (int i = 0; true; i++) {
+					char a = var_value[i];
+					if (a == '\0')
+						break;
+					*res_ptr++ = a;
+				}
+            }
+            var_name_start = NULL;
+            if (c == '}') {
+              bracket = false;
+              continue;
+            }
+          }
+        }
+      }
+      if (c == '$') {
+        /* Start parsing variable */
+        if (*src_ptr == '{') {
+          bracket = true;
+          src_ptr++;
+        }
+        var_name_start = src_ptr;
+        continue;
+      }
+      /* Normal char */
+      *res_ptr++ = c;
+      if (c == '\0')
+        break;
+    }
+
+    printf("Expanded: %s", cmdline_exp);
+    cmdline = cmdline_exp;
+  }
+#endif
+
   /* Parse out the command at the beginning of the line */
 
   saveptr = cmdline;
@@ -1349,6 +1483,12 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
        * command status.
        */
 
+#ifndef CONFIG_DISABLE_ENVIRON
+      if (cmdline_exp != NULL) {
+        free(cmdline_exp);
+      }
+#endif
+
       return OK;
     }
 
@@ -1454,6 +1594,12 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 
       /* Save the result:  success if 0; failure if 1 */
 
+#ifndef CONFIG_DISABLE_ENVIRON
+      if (cmdline_exp != NULL) {
+        free(cmdline_exp);
+      }
+#endif
+
       return nsh_saveresult(vtbl, ret != OK);
     }
 
@@ -1497,6 +1643,12 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
 
       /* Save the result:  success if 0; failure if 1 */
 
+#ifndef CONFIG_DISABLE_ENVIRON
+      if (cmdline_exp != NULL) {
+        free(cmdline_exp);
+      }
+#endif
+
       return nsh_saveresult(vtbl, ret != OK);
     }
 
@@ -1673,6 +1825,12 @@ int nsh_parse(FAR struct nsh_vtbl_s *vtbl, char *cmdline)
    * command task succeeded).
    */
 
+#ifndef CONFIG_DISABLE_ENVIRON
+  if (cmdline_exp != NULL) {
+    free(cmdline_exp);
+  }
+#endif
+
   return nsh_saveresult(vtbl, false);
 
 #ifndef CONFIG_NSH_DISABLEBG
@@ -1683,5 +1841,11 @@ errout_with_redirect:
     }
 #endif
 errout:
+#ifndef CONFIG_DISABLE_ENVIRON
+  if (cmdline_exp != NULL) {
+    free(cmdline_exp);
+  }
+#endif
+
   return nsh_saveresult(vtbl, true);
 }