Merge openenclave#3775

3775: Add ftruncate r=mingweishih a=thomasten Added support for the ftruncate syscall. Co-authored-by: Thomas Tendyck <[email protected]>
BRMcLaren · Dec 28, 2020 · 3b6f413 · 3b6f413
2 parents 6ece1bc + 00fb310
commit 3b6f413
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diff --git a/docs/SystemEdls.md b/docs/SystemEdls.md
@@ -83,6 +83,7 @@ oe_syscall_link_ocall | link | - |
 oe_syscall_unlink_ocall | unlink | - |
 oe_syscall_rename_ocall | rename | - |
 oe_syscall_truncate_ocall | truncate | - |
+oe_syscall_ftruncate_ocall | ftruncate | - |
 oe_syscall_mkdir_ocall | mkdir | - |
 oe_syscall_rmdir_ocall | rmdir | - |
 oe_syscall_fcntl_ocall | fcntl | - |

diff --git a/docs/UsingTheIOSubsystem.md b/docs/UsingTheIOSubsystem.md
@@ -382,6 +382,7 @@ functions.
 | dup2              | none                                                     |
 | fdatasync         | none                                                     |
 | fsync             | none                                                     |
+| ftruncate         | none                                                     |
 | getcwd            | none                                                     |
 | getdomainname     | none                                                     |
 | getegid           | none                                                     |
@@ -401,6 +402,7 @@ functions.
 | read              | none                                                     |
 | rmdir             | none                                                     |
 | sleep             | none                                                     |
+| truncate          | none                                                     |
 | unlink            | none                                                     |
 | write             | none                                                     |
 |                   | <img width="1000">                                       |

diff --git a/host/linux/syscall.c b/host/linux/syscall.c
@@ -389,6 +389,13 @@ int oe_syscall_truncate_ocall(const char* path, oe_off_t length)
     return truncate(path, length);
 }
 
+int oe_syscall_ftruncate_ocall(oe_host_fd_t fd, oe_off_t length)
+{
+    errno = 0;
+
+    return ftruncate((int)fd, length);
+}
+
 int oe_syscall_mkdir_ocall(const char* pathname, oe_mode_t mode)
 {
     errno = 0;

diff --git a/host/windows/syscall.c b/host/windows/syscall.c
@@ -2032,6 +2032,41 @@ int oe_syscall_truncate_ocall(const char* pathname, oe_off_t length)
     return ret;
 }
 
+int oe_syscall_ftruncate_ocall(oe_host_fd_t fd, oe_off_t length)
+{
+    const HANDLE h = (HANDLE)fd;
+    LARGE_INTEGER new_offset = {0};
+    LARGE_INTEGER old_offset = {0};
+
+    if (!SetFilePointerEx(h, new_offset, &old_offset, FILE_CURRENT))
+    {
+        _set_errno(_winerr_to_errno(GetLastError()));
+        return -1;
+    }
+
+    new_offset.QuadPart = length;
+    if (!SetFilePointerEx(h, new_offset, NULL, FILE_BEGIN))
+    {
+        _set_errno(_winerr_to_errno(GetLastError()));
+        return -1;
+    }
+
+    if (!SetEndOfFile(h))
+    {
+        _set_errno(_winerr_to_errno(GetLastError()));
+        SetFilePointerEx(h, old_offset, NULL, FILE_BEGIN);
+        return -1;
+    }
+
+    if (!SetFilePointerEx(h, old_offset, NULL, FILE_BEGIN))
+    {
+        _set_errno(_winerr_to_errno(GetLastError()));
+        return -1;
+    }
+
+    return 0;
+}
+
 int oe_syscall_mkdir_ocall(const char* pathname, oe_mode_t mode)
 {
     int ret = -1;

diff --git a/include/openenclave/edl/fcntl.edl b/include/openenclave/edl/fcntl.edl
@@ -177,6 +177,11 @@ enclave
             oe_off_t length)
             propagate_errno;
 
+        int oe_syscall_ftruncate_ocall(
+            oe_host_fd_t fd,
+            oe_off_t length)
+            propagate_errno;
+
         int oe_syscall_mkdir_ocall(
             [in, string] const char* pathname,
             oe_mode_t mode)

diff --git a/include/openenclave/internal/syscall/declarations.h b/include/openenclave/internal/syscall/declarations.h
@@ -175,6 +175,7 @@ OE_DECLARE_SYSCALL2(SYS_flock);
 OE_DECLARE_SYSCALL2(SYS_fstat);
 OE_DECLARE_SYSCALL4(SYS_fstatat);
 OE_DECLARE_SYSCALL1_M(SYS_fsync);
+OE_DECLARE_SYSCALL2(SYS_ftruncate);
 // SYS_futex is needed for compiling musl/src/internal/pthread_impl.h
 // It doesn't have to be implemented.
 // It is called with 3 or 4 arguments.

diff --git a/include/openenclave/internal/syscall/fd.h b/include/openenclave/internal/syscall/fd.h
@@ -66,6 +66,8 @@ typedef struct _oe_file_ops
 
     int (*fstat)(oe_fd_t* file, struct oe_stat_t* buf);
 
+    int (*ftruncate)(oe_fd_t* file, oe_off_t length);
+
     int (*fsync)(oe_fd_t* file);
     int (*fdatasync)(oe_fd_t* file);
 } oe_file_ops_t;

diff --git a/include/openenclave/internal/syscall/unistd.h b/include/openenclave/internal/syscall/unistd.h
@@ -52,6 +52,8 @@ int oe_truncate(const char* path, oe_off_t length);
 
 int oe_truncate_d(uint64_t devid, const char* path, oe_off_t length);
 
+int oe_ftruncate(int fd, oe_off_t length);
+
 #endif /* !defined(WIN32) */
 
 int oe_link(const char* oldpath, const char* newpath);

diff --git a/libc/CMakeLists.txt b/libc/CMakeLists.txt
@@ -782,6 +782,7 @@ add_enclave_library(
   ${MUSLSRC}/unistd/close.c
   ${MUSLSRC}/unistd/fdatasync.c
   ${MUSLSRC}/unistd/fsync.c
+  ${MUSLSRC}/unistd/ftruncate.c
   ${MUSLSRC}/unistd/getgid.c
   ${MUSLSRC}/unistd/getegid.c
   ${MUSLSRC}/unistd/getuid.c

diff --git a/syscall/consolefs.c b/syscall/consolefs.c
@@ -490,6 +490,15 @@ static int _consolefs_fstat(oe_fd_t* file, struct oe_stat_t* buf)
     return -1;
 }
 
+static int _consolefs_ftruncate(oe_fd_t* file, oe_off_t length)
+{
+    OE_UNUSED(file);
+    OE_UNUSED(length);
+    OE_RAISE_ERRNO(OE_EINVAL);
+done:
+    return -1;
+}
+
 static int _consolefs_fsync(oe_fd_t* file)
 {
     OE_UNUSED(file);
@@ -513,6 +522,7 @@ static oe_file_ops_t _ops = {
     .pwrite = _consolefs_pwrite,
     .getdents64 = _consolefs_getdents64,
     .fstat = _consolefs_fstat,
+    .ftruncate = _consolefs_ftruncate,
     .fsync = _consolefs_fsync,
     .fdatasync = _consolefs_fsync,
 };

diff --git a/syscall/devices/hostfs/hostfs.c b/syscall/devices/hostfs/hostfs.c
@@ -1359,6 +1359,24 @@ static int _hostfs_truncate(
     return ret;
 }
 
+static int _hostfs_ftruncate(oe_fd_t* desc, oe_off_t length)
+{
+    int ret = -1;
+    const file_t* const file = _cast_file(desc);
+    int retval = -1;
+
+    if (!file)
+        OE_RAISE_ERRNO(OE_EINVAL);
+
+    if (oe_syscall_ftruncate_ocall(&retval, file->host_fd, length) != OE_OK)
+        OE_RAISE_ERRNO(OE_EINVAL);
+
+    ret = retval;
+
+done:
+    return ret;
+}
+
 static int _hostfs_mkdir(
     oe_device_t* device,
     const char* pathname,
@@ -1441,6 +1459,7 @@ static oe_file_ops_t _file_ops =
     .pwrite = _hostfs_pwrite,
     .getdents64 = _hostfs_getdents64,
     .fstat = _hostfs_fstat,
+    .ftruncate = _hostfs_ftruncate,
     .fsync = _hostfs_fsync,
     .fdatasync = _hostfs_fdatasync,
 };

diff --git a/syscall/fdtable.c b/syscall/fdtable.c
@@ -170,6 +170,7 @@ static void _assert_fd(oe_fd_t* desc)
             oe_assert(desc->ops.file.pwrite);
             oe_assert(desc->ops.file.getdents64);
             oe_assert(desc->ops.file.fstat);
+            oe_assert(desc->ops.file.ftruncate);
             oe_assert(desc->ops.file.fsync);
             oe_assert(desc->ops.file.fdatasync);
             break;

diff --git a/syscall/syscall.c b/syscall/syscall.c
@@ -316,6 +316,14 @@ OE_WEAK OE_DEFINE_SYSCALL1_M(SYS_fsync)
     return oe_fsync(fd);
 }
 
+OE_WEAK OE_DEFINE_SYSCALL2(SYS_ftruncate)
+{
+    oe_errno = 0;
+    const int fd = (int)arg1;
+    const ssize_t length = (ssize_t)arg2;
+    return oe_ftruncate(fd, length);
+}
+
 OE_WEAK OE_DEFINE_SYSCALL3_M(SYS_futex)
 {
     OE_UNUSED(arg1);
@@ -1107,6 +1115,7 @@ static long _syscall(
         OE_SYSCALL_DISPATCH(SYS_flock, arg1, arg2);
         OE_SYSCALL_DISPATCH(SYS_fstat, arg1, arg2);
         OE_SYSCALL_DISPATCH(SYS_fsync, arg1);
+        OE_SYSCALL_DISPATCH(SYS_ftruncate, arg1, arg2);
         OE_SYSCALL_DISPATCH(SYS_getcwd, arg1, arg2);
         OE_SYSCALL_DISPATCH(SYS_getdents64, arg1, arg2, arg3);
         OE_SYSCALL_DISPATCH(SYS_getegid);

diff --git a/syscall/unistd.c b/syscall/unistd.c
@@ -545,6 +545,20 @@ int oe_truncate_d(uint64_t devid, const char* path, oe_off_t length)
     return ret;
 }
 
+int oe_ftruncate(int fd, oe_off_t length)
+{
+    int ret = -1;
+    oe_fd_t* file;
+
+    if (!(file = oe_fdtable_get(fd, OE_FD_TYPE_FILE)))
+        OE_RAISE_ERRNO(oe_errno);
+
+    ret = file->ops.file.ftruncate(file, length);
+
+done:
+    return ret;
+}
+
 oe_off_t oe_lseek(int fd, oe_off_t offset, int whence)
 {
     oe_off_t ret = -1;

diff --git a/tests/syscall/fs/enc/enc.cpp b/tests/syscall/fs/enc/enc.cpp
@@ -397,14 +397,35 @@ static void test_truncate_file(FILE_SYSTEM& fs, const char* tmp_dir)
 
     mkpath(path, tmp_dir, "alphabet");
 
-    /* Remove the file. */
+    /* Truncate the file. */
     OE_TEST(fs.truncate(path, 5) == 0);
 
     /* Stat the file. */
     OE_TEST(fs.stat(path, &buf) == 0);
     OE_TEST(buf.st_size == 5);
 }
 
+template <class FILE_SYSTEM>
+static void test_ftruncate_file(FILE_SYSTEM& fs, const char* tmp_dir)
+{
+    char path[OE_PAGE_SIZE];
+    typename FILE_SYSTEM::stat_type buf;
+
+    printf("--- %s()\n", __FUNCTION__);
+
+    mkpath(path, tmp_dir, "alphabet");
+
+    /* Truncate the file. */
+    const auto file = fs.open(path, O_WRONLY, 0);
+    OE_TEST(file);
+    OE_TEST(fs.ftruncate(file, 4) == 0);
+    OE_TEST(fs.close(file) == 0);
+
+    /* Stat the file. */
+    OE_TEST(fs.stat(path, &buf) == 0);
+    OE_TEST(buf.st_size == 4);
+}
+
 template <class FILE_SYSTEM>
 static void test_unlink_file(FILE_SYSTEM& fs, const char* tmp_dir)
 {
@@ -444,6 +465,7 @@ void test_common(FILE_SYSTEM& fs, const char* tmp_dir)
     test_rename_file(fs, tmp_dir);
     test_readdir(fs, tmp_dir);
     test_truncate_file(fs, tmp_dir);
+    test_ftruncate_file(fs, tmp_dir);
     test_unlink_file(fs, tmp_dir);
     test_invalid_path(fs);
     cleanup(fs, tmp_dir);

diff --git a/tests/syscall/fs/enc/file_system.h b/tests/syscall/fs/enc/file_system.h
@@ -146,6 +146,11 @@ class oe_fd_file_system
         return oe_truncate(path, length);
     }
 
+    int ftruncate(file_handle file, off_t length)
+    {
+        return oe_ftruncate(file, length);
+    }
+
   private:
 };
 
@@ -306,6 +311,11 @@ class fd_file_system
         return ::truncate(path, length);
     }
 
+    int ftruncate(file_handle file, off_t length)
+    {
+        return ::ftruncate(file, length);
+    }
+
   private:
 };
 
@@ -584,6 +594,11 @@ class stream_file_system
         return ::truncate(path, length);
     }
 
+    int ftruncate(file_handle file, off_t length)
+    {
+        return ::ftruncate(fileno(file), length);
+    }
+
   private:
 };