Check whether source file is not a directory

Prevent directory.
Accept symbolic link.

テストで失敗する

src/as/as.c

@@ -450,8 +450,9 @@ int main(int argc, char *argv[]) {
 
   if (iarg < argc) {
     for (int i = iarg; i < argc; ++i) {
-      FILE *fp = fopen(argv[i], "r");
-      if (fp == NULL)
+      const char *filename = argv[i];
+      FILE *fp;
+      if (!is_file(filename) || (fp = fopen(filename, "r")) == NULL)
         error("Cannot open %s\n", argv[i]);
       parse_file(fp, argv[i], section_irs, &label_table);
       fclose(fp);

src/cc/cc1.c

@@ -76,8 +76,8 @@ int main(int argc, char *argv[]) {
   if (iarg < argc) {
     for (int i = iarg; i < argc; ++i) {
       const char *filename = argv[i];
-      FILE *ifp = fopen(filename, "r");
-      if (ifp == NULL)
+      FILE *ifp;
+      if (!is_file(filename) || (ifp = fopen(filename, "r")) == NULL)
         error("Cannot open file: %s\n", filename);
       compile1(ifp, filename, toplevel);
       fclose(ifp);

src/cpp/cpp.c

@@ -60,8 +60,8 @@ int main(int argc, char *argv[]) {
   if (iarg < argc) {
     for (int i = iarg; i < argc; ++i) {
       const char *filename = argv[i];
-      FILE *fp = fopen(filename, "r");
-      if (fp == NULL)
+      FILE *fp;
+      if (!is_file(filename) || (fp = fopen(filename, "r")) == NULL)
         error("Cannot open file: %s\n", filename);
       fprintf(ofp, "# 1 \"%s\" 1\n", filename);
       preprocess(fp, filename);

src/cpp/preprocessor.c

@@ -84,7 +84,7 @@ static FILE *search_sysinc_next(const char *dir, const char *path, char **pfn) {
       FILE *fp = NULL;
       char *fn = cat_path_cwd(v->data[idx], path);
       if (registered_pragma_once(fn) ||
-          (fp = fopen(fn, "r")) != NULL) {
+          (is_file(fn) && (fp = fopen(fn, "r")) != NULL)) {
         *pfn = fn;
         return fp;
       }
@@ -176,7 +176,8 @@ static void handle_include(const char *p, Stream *stream, bool next) {
     fn = cat_path_cwd(dir, path);
     if (registered_pragma_once(fn))
       return;
-    fp = fopen(fn, "r");
+    if (is_file(fn))
+      fp = fopen(fn, "r");
   }
   if (fp == NULL) {
     if (next) fp = search_sysinc_next(dir, path, &fn);

src/ld/archive.c

@@ -24,8 +24,8 @@ static uint32_t read4be(FILE *fp) {
 }
 
 Archive *load_archive(const char *filename) {
-  FILE *fp = fopen(filename, "r");
-  if (fp == NULL)
+  FILE *fp;
+  if (!is_file(filename) || (fp = fopen(filename, "r")) == NULL)
     return NULL;
 
   Archive *ar = malloc_or_die(sizeof(*ar));

src/ld/elfobj.c

@@ -134,8 +134,8 @@ void elfobj_init(ElfObj *elfobj) {
 }
 
 bool open_elf(const char *fn, ElfObj *elfobj) {
-  FILE *fp = fopen(fn, "r");
-  if (fp == NULL) {
+  FILE *fp;
+  if (!is_file(fn) || (fp = fopen(fn, "r")) == NULL) {
     fprintf(stderr, "cannot open: %s\n", fn);
   } else {
     if (read_elf(elfobj, fp, fn))

src/util/util.c

@@ -6,6 +6,7 @@
 #include <stdbool.h>
 #include <stdlib.h>  // malloc
 #include <string.h>  // strcmp
+#include <sys/stat.h>
 
 #include "../version.h"
 #include "table.h"
@@ -241,6 +242,11 @@ void put_padding(FILE *fp, uintptr_t start) {
   }
 }
 
+bool is_file(const char *path) {
+  struct stat st;
+  return stat(path, &st) == 0 && S_ISREG(st.st_mode);
+}
+
 void show_version(const char *exe) {
   printf("%s %s\n", exe, VERSION);
 }

src/util/util.h

@@ -34,6 +34,7 @@ char *join_paths(const char *paths[]);
 char *get_ext(const char *filename);
 char *change_ext(const char *path, const char *ext);
 void put_padding(FILE *fp, uintptr_t start);
+bool is_file(const char *path);
 
 void show_version(const char *exe);
 

src/wcc/wcc.c

@@ -1001,8 +1001,7 @@ static void preprocess_and_compile(FILE *ppout, Vector *sources) {
     const char *filename = sources->data[i];
     FILE *ifp;
     if (filename != NULL) {
-      ifp = fopen(filename, "r");
-      if (ifp == NULL)
+      if (!is_file(filename) || (ifp = fopen(filename, "r")) == NULL)
         error("Cannot open file: %s\n", filename);
     } else {
       ifp = stdin;

src/xcc/main.c

@@ -515,10 +515,8 @@ int main(int argc, char *argv[]) {
     }
 #endif
 
-    enum SourceType st = UnknownSource;
-    if (src == NULL) {
-      st = src_type;
-    } else {
+    enum SourceType st = src_type;
+    if (src != NULL) {
       char *ext = get_ext(src);
       if      (strcasecmp(ext, "c") == 0)  st = Clanguage;
       else if (strcasecmp(ext, "s") == 0)  st = Assembly;