Merge pull request #203 from giuseppe/use-openat2

main: use openat2 where available
2025-09-08 23:07:28 -04:00 · 2020-04-22 08:52:24 -04:00 · 2020-04-22 08:52:24 -04:00 · e70b270460
commit e70b270460
parent f040ab0343 e7051f874b
5 changed files with 84 additions and 22 deletions
--- a/.travis.yml
+++ b/.travis.yml
@ -34,7 +34,7 @@ before_install:
  - (git clone --depth 1 -b 0.51.1 https://github.com/mesonbuild/meson.git; cd meson; sudo python3.5 ./setup.py install)
  - (git clone --depth 1 https://github.com/bats-core/bats-core; cd bats-core; sudo ./install.sh /usr/local)
  - ($GO get github.com/containers/storage; cd $GOPATH/src/github.com/containers/storage; sed -i -e 's|^AUTOTAGS.*$|AUTOTAGS := exclude_graphdriver_devicemapper exclude_graphdriver_btrfs|' Makefile; make GO=$GO GO111MODULE=on containers-storage)
-  - (wget https://github.com/libfuse/libfuse/releases/download/fuse-3.6.2/fuse-3.6.2.tar.xz; tar xf fuse-3.6.2.tar.xz; cd fuse-3.6.2; mkdir build; cd build; meson .. --prefix /usr && ninja && sudo ninja install)
+  - (wget https://github.com/libfuse/libfuse/releases/download/fuse-3.9.1/fuse-3.9.1.tar.xz; tar xf fuse-3.9.1.tar.xz; cd fuse-3.9.1; mkdir build; cd build; meson .. --prefix /usr && ninja && sudo ninja install)
 script:
  - ./autogen.sh || travis_terminate 1;
  - ./configure || travis_terminate 1;
--- a/direct.c
+++ b/direct.c
@ -129,7 +129,7 @@ direct_opendir (struct ovl_layer *l, const char *path)
  cleanup_close int cleanup_fd = -1;
  DIR *dp = NULL;

-  cleanup_fd = TEMP_FAILURE_RETRY (openat (l->fd, path, O_DIRECTORY));
+  cleanup_fd = TEMP_FAILURE_RETRY (safe_openat (l->fd, path, O_DIRECTORY, 0));
  if (cleanup_fd < 0)
    return NULL;

@ -151,7 +151,7 @@ direct_closedir (void *dirp)
 static int
 direct_openat (struct ovl_layer *l, const char *path, int flags, mode_t mode)
 {
-  return TEMP_FAILURE_RETRY (openat (l->fd, path, flags, mode));
+  return TEMP_FAILURE_RETRY (safe_openat (l->fd, path, flags, mode));
 }

 static ssize_t
--- a/main.c
+++ b/main.c
@ -494,7 +494,7 @@ set_fd_opaque (int fd)
          return -1;
    }
 create_opq_whiteout:
-  opq_whiteout_fd = TEMP_FAILURE_RETRY (openat (fd, OPAQUE_WHITEOUT, O_CREAT|O_WRONLY|O_NONBLOCK, 0700));
+  opq_whiteout_fd = TEMP_FAILURE_RETRY (safe_openat (fd, OPAQUE_WHITEOUT, O_CREAT|O_WRONLY|O_NONBLOCK, 0700));
  return (opq_whiteout_fd >= 0 || ret == 0) ? 0 : -1;
 }

@ -2445,7 +2445,7 @@ create_directory (struct ovl_data *lo, int dirfd, const char *name, const struct
  if (ret < 0)
    goto out;

-  ret = dfd = TEMP_FAILURE_RETRY (openat (lo->workdir_fd, wd_tmp_file_name, O_RDONLY));
+  ret = dfd = TEMP_FAILURE_RETRY (safe_openat (lo->workdir_fd, wd_tmp_file_name, O_RDONLY, 0));
  if (ret < 0)
    goto out;

@ -2645,11 +2645,11 @@ copyup (struct ovl_data *lo, struct ovl_node *node)
      goto success;
    }

-  ret = sfd = node->layer->ds->openat (node->layer, node->path, O_RDONLY|O_NONBLOCK, 0755);
+  ret = sfd = node->layer->ds->openat (node->layer, node->path, O_RDONLY|O_NONBLOCK, 0);
  if (sfd < 0)
    goto exit;

-  ret = dfd = TEMP_FAILURE_RETRY (openat (lo->workdir_fd, wd_tmp_file_name, O_CREAT|O_WRONLY, st.st_mode));
+  ret = dfd = TEMP_FAILURE_RETRY (safe_openat (lo->workdir_fd, wd_tmp_file_name, O_CREAT|O_WRONLY, st.st_mode));
  if (dfd < 0)
    goto exit;

@ -2865,7 +2865,7 @@ empty_dirfd (int fd)
            {
              int dfd;

-              dfd = openat (dirfd (dp), dent->d_name, O_DIRECTORY);
+              dfd = safe_openat (dirfd (dp), dent->d_name, O_DIRECTORY, 0);
              if (dfd < 0)
                return -1;

@ -2893,7 +2893,7 @@ empty_dir (struct ovl_layer *l, const char *path)
  cleanup_close int cleanup_fd = -1;
  int ret;

-  cleanup_fd = TEMP_FAILURE_RETRY (openat (l->fd, path, O_DIRECTORY));
+  cleanup_fd = TEMP_FAILURE_RETRY (safe_openat (l->fd, path, O_DIRECTORY, 0));
  if (cleanup_fd < 0)
    return -1;

@ -3171,7 +3171,7 @@ direct_create_file (struct ovl_layer *l, int dirfd, const char *path, uid_t uid,
  /* try to create directly the file if it doesn't need to be chowned.  */
  if (uid == lo->uid && gid == lo->gid)
    {
-      ret = TEMP_FAILURE_RETRY (openat (get_upper_layer (lo)->fd, path, flags, mode));
+      ret = TEMP_FAILURE_RETRY (safe_openat (get_upper_layer (lo)->fd, path, flags, mode));
      if (ret >= 0)
        return ret;
      /* if it fails (e.g. there is a whiteout) then fallback to create it in
@ -3180,7 +3180,7 @@ direct_create_file (struct ovl_layer *l, int dirfd, const char *path, uid_t uid,

  sprintf (wd_tmp_file_name, "%lu", get_next_wd_counter ());

-  fd = TEMP_FAILURE_RETRY (openat (lo->workdir_fd, wd_tmp_file_name, flags, mode));
+  fd = TEMP_FAILURE_RETRY (safe_openat (lo->workdir_fd, wd_tmp_file_name, flags, mode));
  if (fd < 0)
    return -1;
  if (uid != lo->uid || gid != lo->gid)
@ -3590,7 +3590,7 @@ ovl_setattr (fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, stru
      switch (mode & S_IFMT)
        {
        case S_IFREG:
-          cleaned_up_fd = fd = TEMP_FAILURE_RETRY (openat (dirfd, node->path, O_NOFOLLOW|O_NONBLOCK|(to_set & FUSE_SET_ATTR_SIZE ? O_WRONLY : 0)));
+          cleaned_up_fd = fd = TEMP_FAILURE_RETRY (safe_openat (dirfd, node->path, O_NOFOLLOW|O_NONBLOCK|(to_set & FUSE_SET_ATTR_SIZE ? O_WRONLY : 0), 0));
          if (fd < 0)
            {
              fuse_reply_err (req, errno);
@ -3599,7 +3599,7 @@ ovl_setattr (fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, stru
          break;

        case S_IFDIR:
-          cleaned_up_fd = fd = TEMP_FAILURE_RETRY (openat (dirfd, node->path, O_NOFOLLOW|O_NONBLOCK));
+          cleaned_up_fd = fd = TEMP_FAILURE_RETRY (safe_openat (dirfd, node->path, O_NOFOLLOW|O_NONBLOCK, 0));
          if (fd < 0)
            {
              if (errno != ELOOP)
@ -3611,7 +3611,7 @@ ovl_setattr (fuse_req_t req, fuse_ino_t ino, struct stat *attr, int to_set, stru
          break;

        case S_IFLNK:
-          cleaned_up_fd = TEMP_FAILURE_RETRY (openat (dirfd, node->path, O_PATH|O_NOFOLLOW|O_NONBLOCK));
+          cleaned_up_fd = TEMP_FAILURE_RETRY (safe_openat (dirfd, node->path, O_PATH|O_NOFOLLOW|O_NONBLOCK, 0));
          if (cleaned_up_fd < 0)
            {
              fuse_reply_err (req, errno);
@ -3981,7 +3981,7 @@ ovl_rename_exchange (fuse_req_t req, fuse_ino_t parent, const char *name,
  if (pnode == NULL)
    goto error;

-  ret = TEMP_FAILURE_RETRY (openat (node_dirfd (pnode), pnode->path, O_DIRECTORY));
+  ret = TEMP_FAILURE_RETRY (safe_openat (node_dirfd (pnode), pnode->path, O_DIRECTORY, 0));
  if (ret < 0)
    goto error;
  srcfd = ret;
@ -3990,7 +3990,7 @@ ovl_rename_exchange (fuse_req_t req, fuse_ino_t parent, const char *name,
  if (destpnode == NULL)
    goto error;

-  ret = TEMP_FAILURE_RETRY (openat (node_dirfd (destpnode), destpnode->path, O_DIRECTORY));
+  ret = TEMP_FAILURE_RETRY (safe_openat (node_dirfd (destpnode), destpnode->path, O_DIRECTORY, 0));
  if (ret < 0)
    goto error;
  destfd = ret;
@ -4106,7 +4106,7 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
  if (pnode == NULL)
    goto error;

-  ret = TEMP_FAILURE_RETRY (openat (node_dirfd (pnode), pnode->path, O_DIRECTORY));
+  ret = TEMP_FAILURE_RETRY (safe_openat (node_dirfd (pnode), pnode->path, O_DIRECTORY, 0));
  if (ret < 0)
    goto error;
  srcfd = ret;
@ -4115,7 +4115,7 @@ ovl_rename_direct (fuse_req_t req, fuse_ino_t parent, const char *name,
  if (destpnode == NULL)
    goto error;

-  ret = TEMP_FAILURE_RETRY (openat (node_dirfd (destpnode), destpnode->path, O_DIRECTORY));
+  ret = TEMP_FAILURE_RETRY (safe_openat (node_dirfd (destpnode), destpnode->path, O_DIRECTORY, 0));
  if (ret < 0)
    goto error;
  destfd = ret;
@ -4622,7 +4622,7 @@ direct_fsync (struct ovl_layer *l, int fd, const char *path, int datasync)

  if (fd < 0)
    {
-      cfd = openat (l->fd, path, O_NOFOLLOW|O_DIRECTORY);
+      cfd = safe_openat (l->fd, path, O_NOFOLLOW|O_DIRECTORY, 0);
      if (cfd < 0)
          return cfd;
      fd = cfd;
@ -4813,7 +4813,7 @@ ovl_fallocate (fuse_req_t req, fuse_ino_t ino, int mode, off_t offset, off_t len
    }

  dirfd = node_dirfd (node);
-  fd = openat (dirfd, node->path, O_NONBLOCK|O_NOFOLLOW|O_WRONLY, 0755);
+  fd = safe_openat (dirfd, node->path, O_NONBLOCK|O_NOFOLLOW|O_WRONLY, 0);
  if (fd < 0)
    {
      fuse_reply_err (req, errno);
@ -4878,7 +4878,7 @@ ovl_copy_file_range (fuse_req_t req, fuse_ino_t ino_in, off_t off_in, struct fus
      return;
    }

-  fd_dest = TEMP_FAILURE_RETRY (openat (node_dirfd (dnode), dnode->path, O_NONBLOCK|O_NOFOLLOW|O_WRONLY));
+  fd_dest = TEMP_FAILURE_RETRY (safe_openat (node_dirfd (dnode), dnode->path, O_NONBLOCK|O_NOFOLLOW|O_WRONLY, 0));
  if (fd_dest < 0)
    {
      fuse_reply_err (req, errno);
--- a/utils.c
+++ b/utils.c
@ -25,6 +25,10 @@
 #include <fcntl.h>
 #include <string.h>
 #include <sys/sysmacros.h>
+#include <sys/syscall.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/stat.h>

 #ifndef TEMP_FAILURE_RETRY
 #define TEMP_FAILURE_RETRY(expression) \
@ -35,6 +39,62 @@
       __result; }))
 #endif

+#ifndef RESOLVE_IN_ROOT
+# define RESOLVE_IN_ROOT		0x10
+#endif
+#ifndef __NR_openat2
+# define __NR_openat2 437
+#endif
+
+/* List of all valid flags for the open/openat flags argument: */
+#define VALID_OPEN_FLAGS \
+  (O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC | \
+   O_APPEND | O_NDELAY | O_NONBLOCK | O_NDELAY | O_SYNC | O_DSYNC |     \
+   FASYNC | O_DIRECT | O_LARGEFILE | O_DIRECTORY | O_NOFOLLOW |         \
+   O_NOATIME | O_CLOEXEC | O_PATH | O_TMPFILE)
+
+static int
+syscall_openat2 (int dirfd, const char *path, uint64_t flags, uint64_t mode, uint64_t resolve)
+{
+  struct openat2_open_how
+    {
+      uint64_t flags;
+      uint64_t mode;
+      uint64_t resolve;
+    }
+  how =
+    {
+     .flags = flags & VALID_OPEN_FLAGS,
+     .mode = (flags & O_CREAT) ? (mode & 07777) : 0,
+     .resolve = resolve,
+    };
+
+  return (int) syscall (__NR_openat2, dirfd, path, &how, sizeof (how), 0);
+}
+
+int
+safe_openat (int dirfd, const char *pathname, int flags, mode_t mode)
+{
+  static bool openat2_supported = true;
+
+  if (openat2_supported)
+    {
+      int ret;
+
+      ret = syscall_openat2 (dirfd, pathname, flags, mode, RESOLVE_IN_ROOT);
+      if (ret < 0)
+        {
+          if (errno == ENOSYS)
+            openat2_supported = false;
+          if (errno == ENOSYS || errno == EINVAL)
+            goto fallback;
+        }
+      return ret;
+    }
+ fallback:
+  return openat (dirfd, pathname, flags, mode);
+}
+
 int
 file_exists_at (int dirfd, const char *pathname)
 {
@ -148,7 +208,7 @@ open_fd_or_get_path (struct ovl_layer *l, const char *path, char *out, int *fd,
 {
  out[0] = '\0';

-  *fd = l->ds->openat (l, path, O_NONBLOCK|O_NOFOLLOW|flags, 0755);
+  *fd = l->ds->openat (l, path, O_NONBLOCK|O_NOFOLLOW|flags, 0);
  if (*fd < 0 && (errno == ELOOP || errno == EISDIR || errno == ENXIO))
    {
      strconcat3 (out, PATH_MAX, l->path, "/", path);
--- a/utils.h
+++ b/utils.h
@ -53,4 +53,6 @@ int open_fd_or_get_path (struct ovl_layer *l, const char *path, char *out, int *
 void statx_to_stat (struct statx *stx, struct stat *st);
 # endif

+int safe_openat (int dirfd, const char *pathname, int flags, mode_t mode);
+
 #endif