tools/nxstyle: Verify relative path in the file header

tools/Makefile.host

@@ -131,7 +131,8 @@ endif
 # nxstyle - Check a file for compliance to NuttX coding style
 
 nxstyle$(HOSTEXEEXT): nxstyle.c
-	$(Q) $(HOSTCC) $(HOSTCFLAGS) -o nxstyle$(HOSTEXEEXT) nxstyle.c
+	$(Q) $(HOSTCC) $(HOSTCFLAGS) -DTOPDIR=\"$(realpath $(TOPDIR))\" \
+		-o nxstyle$(HOSTEXEEXT) nxstyle.c
 
 ifdef HOSTEXEEXT
 nxstyle: nxstyle$(HOSTEXEEXT)

tools/nxstyle.c

@@ -118,7 +118,6 @@ struct file_section_s
  * Private data
  ********************************************************************************/
 
-static char *g_file_name        = "";
 static enum file_e g_file_type  = UNKNOWN;
 static enum section_s g_section = NO_SECTION;
 static int g_maxline            = DEFAULT_WIDTH;
@@ -127,6 +126,7 @@ static int g_verbose            = 2;
 static int g_rangenumber        = 0;
 static int g_rangestart[RANGE_NUMBER];
 static int g_rangecount[RANGE_NUMBER];
+static char g_file_name[PATH_MAX];
 
 static const struct file_section_s g_section_info[] =
 {
@@ -677,7 +677,13 @@ int main(int argc, char **argv, char **envp)
       show_usage(argv[0], 1, "No file name given.");
     }
 
-  g_file_name = argv[optind];
+  /* Resolve the absolute path for the input file */
+
+  if (realpath(argv[optind], g_file_name) == NULL)
+    {
+      FATALFL("Failed to resolve absolute path.", g_file_name);
+      return 1;
+    }
 
   /* Are we parsing a header file? */
 
@@ -831,6 +837,108 @@ int main(int argc, char **argv, char **envp)
                ERROR("Missing file header comment block", lineno, 1);
             }
 
+          if (lineno == 2)
+            {
+              if (line[n] == '*' && line[n + 1] == '\n')
+                {
+                  ERROR("Missing relative file path in file header", lineno,
+                        n);
+                }
+              else if (isspace(line[n + 2]))
+                {
+                  ERROR("Too many whitespaces before relative file path",
+                        lineno, n);
+                }
+              else
+                {
+                  const char *apps_dir = "apps/";
+                  const size_t apps_len = strlen(apps_dir);
+                  size_t offset;
+
+#ifdef TOPDIR
+                  /* TOPDIR macro contains the absolute path to the "nuttx"
+                   * root directory. It should have been defined via Makefile
+                   * and it is required to accurately evaluate the relative
+                   * path contained in the file header. Otherwise, skip this
+                   * verification.
+                   */
+
+                  char *basedir = strstr(g_file_name, TOPDIR);
+                  if (basedir != NULL)
+                    {
+                      /* Add 1 to the offset for the slash character */
+
+                      offset = strlen(TOPDIR) + 1;
+
+                      /* Duplicate the line from the beginning of the
+                       * relative file path, removing the '\n' at the end of
+                       * the string.
+                       */
+
+                      char *line_dup = strndup(&line[n + 2],
+                                               strlen(&line[n + 2]) - 1);
+
+                      if (strcmp(line_dup, basedir + offset) != 0)
+                        {
+                          ERROR("Relative file path does not match actual file",
+                                lineno, n);
+                        }
+
+                      free(line_dup);
+                    }
+                  else if (strncmp(&line[n + 2], apps_dir, apps_len) != 0)
+                    {
+                      /* g_file_name neither belongs to "nuttx" repository
+                       * nor begins with the root dir of the other
+                       * repository (e.g. "apps/")
+                       */
+
+                      ERROR("Path relative to repository other than \"nuttx\" "
+                            "must begin with the root directory", lineno, n);
+                    }
+                  else
+                    {
+#endif
+
+                      offset = 0;
+
+                      if (strncmp(&line[n + 2], apps_dir, apps_len) == 0)
+                        {
+                          /* Input file belongs to the "apps" repository */
+
+                          /* Calculate the offset to the first directory
+                           * after the "apps/" folder.
+                           */
+
+                          offset += apps_len;
+                        }
+
+                      /* Duplicate the line from the beginning of the
+                       * relative file path, removing the '\n' at the end of
+                       * the string.
+                       */
+
+                      char *line_dup = strndup(&line[n + 2],
+                                              strlen(&line[n + 2]) - 1);
+
+                      ssize_t base =
+                        strlen(g_file_name) - strlen(&line_dup[offset]);
+
+                      if (base < 0 ||
+                          (base != 0 && g_file_name[base - 1] != '/') ||
+                          strcmp(&g_file_name[base], &line_dup[offset]) != 0)
+                        {
+                          ERROR("Relative file path does not match actual file",
+                                lineno, n);
+                        }
+
+                      free(line_dup);
+#ifdef TOPDIR
+                    }
+#endif
+                }
+            }
+
           /* Check for a blank line following a right brace */
 
           if (bfunctions && lineno == rbrace_lineno + 1)