Fix fdopendir so dirfd stays open until closedir (for fstatat etc)

Makefile

@@ -54,7 +54,7 @@ FORCE_ARCH      ?=
 ARCHFLAGS       ?=
 LIPO            ?= lipo
 CC              ?= cc $(ARCHFLAGS)
-CFLAGS          ?= -Os -Wall
+CFLAGS          ?= -Os -Wall -Wno-deprecated-declarations
 DLIBCFLAGS      ?= -fPIC
 SLIBCFLAGS      ?=
 CXX             ?= c++ $(ARCHFLAGS)
@@ -84,7 +84,7 @@ FIND_LIBHEADERS := find $(SRCINCDIR) -type f \( -name '*.h' -o \
 LIBHEADERS      := $(shell $(FIND_LIBHEADERS))
 ALLHEADERS      := $(LIBHEADERS) $(wildcard $(SRCDIR)/*.h)
 
-MULTISRCS       := $(SRCDIR)/fdopendir.c
+MULTISRCS       := # Used to have $(SRCDIR)/fdopendir.c because it used struct stat
 ADDSRCS         := $(SRCDIR)/add_symbols.c
 LIBSRCS         := $(filter-out $(MULTISRCS) $(ADDSRCS),$(wildcard $(SRCDIR)/*.c))
 

README.md

@@ -41,7 +41,10 @@ Wrapped headers and replaced functions are:
   </tr>
   <tr>
     <td><code>dirent.h</code></td>
-    <td>Adds <code>fdopendir</code> function</td>
+    <td>Adds <code>fdopendir</code> function, and wraps <code>opendir</code>,
+    <code>readdir</code>, <code>readdir_r</code>, <code>rewinddir</code>,
+    <code>seekdir</code>, <code>telldir</code>, <code>dirfd</code>, and
+    <code>closedir</code>, to support <code>fdopendir</code></td>
     <td>OSX10.9</td>
   </tr>
   <tr>

include/dirent.h

@@ -1,6 +1,7 @@
 
 /*
  * Copyright (c) 2019
+ * Copyright (c) 2023 raf <raf@raf.org>, Tavian Barnes <tavianator@tavianator.com>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -27,6 +28,14 @@
 /* fdopendir */
 #if __MP_LEGACY_SUPPORT_FDOPENDIR__
 
+/* Wrapper struct for DIR */
+typedef struct __MP_LEGACY_SUPPORT_DIR __MP_LEGACY_SUPPORT_DIR;
+struct __MP_LEGACY_SUPPORT_DIR {
+    DIR *__mpls_dir;
+    int __mpls_dirfd;
+};
+#define DIR __MP_LEGACY_SUPPORT_DIR
+
 __MP__BEGIN_DECLS
 
 #ifndef __DARWIN_ALIAS_I
@@ -35,7 +44,47 @@ extern DIR *fdopendir(int fd) __DARWIN_ALIAS(fdopendir);
 extern DIR *fdopendir(int fd) __DARWIN_ALIAS_I(fdopendir);
 #endif
 
-__MP__END_DECLS
+/* Wrapper functions/macros to support fdopendir */
+extern DIR *__mpls_opendir(const char *name);
+extern int __mpls_closedir(DIR *dir);
+extern int __mpls_dirfd(DIR *dir);
+
+#define opendir(name)      __mpls_opendir(name)
+#define closedir(dir)      __mpls_closedir(dir)
+
+#ifndef __MP_LEGACY_SUPPORT_NO_DIRFD_MACRO
+#undef dirfd
+#define dirfd(dir)         __mpls_dirfd(dir)
 #endif
 
+static inline struct dirent *__mpls_readdir(DIR *dir) {
+    return readdir(dir->__mpls_dir);
+}
+
+static inline int __mpls_readdir_r(DIR *dir, struct dirent *entry, struct dirent **result) {
+    return readdir_r(dir->__mpls_dir, entry, result);
+}
+
+static inline void __mpls_rewinddir(DIR *dir) {
+    rewinddir(dir->__mpls_dir);
+}
+
+static inline void __mpls_seekdir(DIR *dir, long loc) {
+    seekdir(dir->__mpls_dir, loc);
+}
+
+static inline long __mpls_telldir(DIR *dir) {
+    return telldir(dir->__mpls_dir);
+}
+
+#define readdir __mpls_readdir
+#define readdir_r __mpls_readdir_r
+#define rewinddir __mpls_rewinddir
+#define seekdir __mpls_seekdir
+#define telldir __mpls_telldir
+
+__MP__END_DECLS
+
+#endif /* __MP_LEGACY_SUPPORT_FDOPENDIR__ */
+
 #endif /* _MACPORTS_DIRENT_H_ */

src/best_fchdir.c

@@ -1,5 +1,6 @@
 /*-
  * Copyright (c) 2019
+ * Copyright (c) 2023 raf <raf@raf.org>
  *
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
@@ -30,7 +31,10 @@ int best_fchdir(int dirfd)
   return syscall(SYS___pthread_fchdir, dirfd);
 #else
 /* Tiger does not have kernel support for __pthread_fchdir, so we have to fall back to fchdir */
-/* unless we can come up with a per-thread compatible implementation that works on Tiger */
+/* unless we can come up with a per-thread compatible implementation that works on Tiger. */
+/* Accept dirfd == -1 (which is meaningful for __pthread_fchdir) but do nothing with it. */
+  if (dirfd == -1)
+    return 0;
   return syscall(SYS_fchdir, dirfd);
 #endif
 }

src/fdopendir.c

@@ -1,6 +1,7 @@
 
-/*-
+/*
  * Copyright (c) 2019
+ * Copyright (c) 2023 raf <raf@raf.org>, Tavian Barnes <tavianator@tavianator.com>
  *
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
@@ -22,74 +23,123 @@
 
 #include "common-priv.h"
 
+#define __MP_LEGACY_SUPPORT_NO_DIRFD_MACRO
+
+#include <stdlib.h>
 #include <dirent.h>
 #include <sys/errno.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <fcntl.h>
+
+#undef DIR
+#undef opendir
+#undef closedir
 
 
 /*
  * Implementation behavior largely follows these man page descriptions:
  *
  * https://www.freebsd.org/cgi/man.cgi?query=fdopendir&sektion=3
  * https://linux.die.net/man/3/fdopendir
+ *
+ * On success, this function returns allocated memory that must be
+ * deallocated by __mpls_closedir() (see closedir() macro in <dirent.h>).
  */
 
-DIR *fdopendir(int dirfd) {
-    DIR *dir;
-    struct stat st;
-    int oldCWD = -1;
+__MP_LEGACY_SUPPORT_DIR *fdopendir(int dirfd) {
 
-    if (fstat(dirfd, &st) < 0)
-        return 0;
+    /* Check dirfd here (for macos-10.4, see _ATCALL() and best_fchdir()) */
 
-    if (!S_ISDIR(st.st_mode)) {
-        errno = ENOTDIR;
+    if (dirfd != AT_FDCWD && dirfd < 0) {
+        errno = EBADF;
         return 0;
     }
 
-    if (dirfd == AT_FDCWD) {
-        dir = opendir (".");
-        /* dirfd can be closed only upon success */
-        if (dir) PROTECT_ERRNO(close(dirfd));
-        return dir;
-    }
+    /* Open the supplied directory safely */
 
-    oldCWD = open(".", O_RDONLY);
-    if (oldCWD == -1)
+    DIR *dir = _ATCALL(dirfd, ".", NULL, opendir("."));
+    if (!dir)
         return 0;
 
-    if(best_fchdir(dirfd) < 0) {
-        if (oldCWD != -1) PROTECT_ERRNO(close(oldCWD));
+    /* Wrap it and return it (with the supplied directory file descriptor) */
+
+    __MP_LEGACY_SUPPORT_DIR *mplsdir = malloc(sizeof(*mplsdir));
+    if (!mplsdir) {
+        (void)closedir(dir);
+        errno = ENOMEM;
         return 0;
     }
 
-    dir = opendir (".");
+    mplsdir->__mpls_dir = dir;
+    mplsdir->__mpls_dirfd = dirfd;
+
+    return mplsdir;
+}
 
-    if (best_fchdir(oldCWD) < 0) {
-        if (dir) PROTECT_ERRNO(closedir(dir));
-        if (oldCWD != -1) PROTECT_ERRNO(close(oldCWD));
+/*
+ * Wrapped version of opendir() for fdopendir() compatibility
+ *
+ * On success, this function returns allocated memory that must be
+ * deallocated by __mpls_closedir() (see closedir() macro in <dirent.h>).
+ */
+
+__MP_LEGACY_SUPPORT_DIR *__mpls_opendir(const char *name) {
+
+    DIR *dir = opendir(name);
+    if (!dir)
+        return 0;
+
+    __MP_LEGACY_SUPPORT_DIR *mplsdir = malloc(sizeof(*mplsdir));
+    if (!mplsdir) {
+        (void)closedir(dir);
+        errno = ENOMEM;
         return 0;
     }
 
-    if (oldCWD != -1)
-        PROTECT_ERRNO(close(oldCWD));
+    mplsdir->__mpls_dir = dir;
+    mplsdir->__mpls_dirfd = -1;
+
+    return mplsdir;
+}
+
+/*
+ * Wrapped version of closedir() for fdopendir() compatibility (see
+ * closedir() macro in <dirent.h>).
+ *
+ * This function deallocates memory that was allocated by fdopendir() or
+ * __mpls_opendir().
+ */
+
+int __mpls_closedir(__MP_LEGACY_SUPPORT_DIR *mplsdir) {
+
+    if (!mplsdir) {
+        errno = EBADF;
+        return -1;
+    }
+
+    int rc = closedir(mplsdir->__mpls_dir);
+
+    if (mplsdir->__mpls_dirfd != AT_FDCWD && mplsdir->__mpls_dirfd != -1)
+        PROTECT_ERRNO(close(mplsdir->__mpls_dirfd));
+
+    free(mplsdir);
+
+    return rc;
+}
+
+/*
+ * Wrapped version of dirfd() for fdopendir() compatibility because dirfd()
+ * itself is already a macro (see dirfd() macro in <dirent.h>).
+ */
+
+int __mpls_dirfd(__MP_LEGACY_SUPPORT_DIR *mplsdir) {
 
+    /* Return the supplied directory file descriptor if there was one */
 
-    /*
-     * FIXME -- this recently added bit makes the fdopendir tests fail on Tiger.
-     * check the whole commit where it was added to make sure it is
-     * doing the proper thing on all systems. Probably need more extensive tests
-     * to execise the whole system more aggressively.
-     */
+    if (mplsdir->__mpls_dirfd != AT_FDCWD && mplsdir->__mpls_dirfd != -1)
+        return mplsdir->__mpls_dirfd;
 
-#if __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050
-    /* dirfd can be closed only upon success */
-    if (dir && dirfd != -1) PROTECT_ERRNO(close(dirfd));
-#endif
+    /* Otherwise call the underlying dirfd() macro */
 
-    return dir;
+    return dirfd(mplsdir->__mpls_dir);
 }
 
 #endif /* __MP_LEGACY_SUPPORT_FDOPENDIR__ */

test/test_fdopendir.c

@@ -1,6 +1,7 @@
 
 /*
  * Copyright (c) 2019
+ * Copyright (c) 2023 raf <raf@raf.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -15,9 +16,11 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#include <stdlib.h>
 #include <dirent.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/errno.h>
 #include <unistd.h>
 #include <limits.h>
 #include <fcntl.h>
@@ -55,6 +58,29 @@ int main() {
     }
 
     close(dfd);
+
+    /* Try to use fdopendir with stdin - Should fail with ENOTDIR */
+
+    if ((dir = fdopendir(STDIN_FILENO))) {
+        fprintf(stderr, "fdopendir(stdin) should have failed\n");
+        (void)closedir(dir);
+        return 1;
+    } else if (errno != ENOTDIR) {
+        perror("fdopendir(stdin) should have failed with ENOTDIR");
+        return 1;
+    }
+
+    /* Try to use fdopendir with -1 - Should fail with EBADF */
+
+    if ((dir = fdopendir(-1))) {
+        fprintf(stderr, "fdopendir(-1) should have failed\n");
+        (void)closedir(dir);
+        return 1;
+    } else if (errno != EBADF) {
+        perror("fdopendir(-1) should have failed with EBADF");
+        return 1;
+    }
+
     return 0;
 }
 

test/test_fmemopen.c

@@ -108,10 +108,10 @@ test_autoalloc()
      * Let fmemopen allocate the buffer.
      */
 
-    char str[] = "A quick test";
+    /* char str[] = "A quick test"; */
     FILE *fp;
     long pos;
-    size_t nofw, nofr, i;
+    size_t nofw, i;
     int rc;
 
     /* Open a FILE * using fmemopen. */