diff --git a/arm-software/embedded/llvmlibc-support/semihost/semihost.cpp b/arm-software/embedded/llvmlibc-support/semihost/semihost.cpp
index db0781dfefa4..e51bfd08b7dc 100644
--- a/arm-software/embedded/llvmlibc-support/semihost/semihost.cpp
+++ b/arm-software/embedded/llvmlibc-support/semihost/semihost.cpp
@@ -1,29 +1,168 @@
 //
-// Copyright (c) 2022-2025, Arm Limited and affiliates.
+// Copyright (c) 2022-2026, Arm Limited and affiliates.
 //
-// Part of the Arm Toolchain project, under the Apache License v2.0 with LLVM Exceptions. 
-// See https://llvm.org/LICENSE.txt for license information.
+// Part of the Arm Toolchain project, under the Apache License v2.0 with LLVM
+// Exceptions. See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 
 #include "semihost.h"
 #include "platform.h"
 
+#include <errno.h>
 #include <stddef.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 
 namespace {
+// File cookies
+inline constexpr size_t DEFAULT_FILE_COOKIE_COUNT = 4;
+__llvm_libc_semihost_file_cookie
+    default_file_cookies[DEFAULT_FILE_COOKIE_COUNT];
+} // namespace
 
-void stdio_open(struct __llvm_libc_stdio_cookie *cookie, size_t mode) {
-  const char std_stream_name[] = ":tt";
+extern "C" {
+// Override this weak definition with a pool backed by an application-owned
+// array to change the maximum number of simultaneously open files.
+__attribute__((weak)) __llvm_libc_semihost_file_cookie_pool
+    __llvm_libc_semihost_file_cookie_storage = {default_file_cookies,
+                                                DEFAULT_FILE_COOKIE_COUNT};
+struct __llvm_libc_stdio_cookie __llvm_libc_stdin_cookie;
+struct __llvm_libc_stdio_cookie __llvm_libc_stdout_cookie;
+struct __llvm_libc_stdio_cookie __llvm_libc_stderr_cookie;
+}
+
+namespace {
+// File cookie helpers
+bool is_std_stream(void *cookie) {
+  return cookie == &__llvm_libc_stdin_cookie ||
+         cookie == &__llvm_libc_stdout_cookie ||
+         cookie == &__llvm_libc_stderr_cookie;
+}
+
+size_t get_handle(void *cookie) {
+  return static_cast<__llvm_libc_stdio_cookie *>(cookie)->handle;
+}
+
+__llvm_libc_semihost_file_cookie *allocate_file() {
+  for (size_t i = 0; i < __llvm_libc_semihost_file_cookie_storage.size; ++i) {
+    auto *cookie = &__llvm_libc_semihost_file_cookie_storage.cookies[i];
+    if (!cookie->in_use) {
+      cookie->in_use = true;
+      cookie->position = 0;
+      return cookie;
+    }
+  }
+  return nullptr;
+}
+
+void release_file(void *cookie) {
+  static_cast<__llvm_libc_semihost_file_cookie *>(cookie)->in_use = false;
+}
+
+off_t get_file_position(void *cookie) {
+  return static_cast<__llvm_libc_semihost_file_cookie *>(cookie)->position;
+}
+
+void set_file_position(void *cookie, off_t position) {
+  static_cast<__llvm_libc_semihost_file_cookie *>(cookie)->position = position;
+}
+
+void advance_file_position(void *cookie, size_t amount) {
+  set_file_position(cookie,
+                    get_file_position(cookie) + static_cast<off_t>(amount));
+}
+} // namespace
+
+namespace {
+// Helper functions implemented here to avoid dependency on libc which is not
+// available in LLVM libc hermetic testing.
+int _isspace(char ch) {
+  return ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' || ch == '\v' ||
+         ch == '\f';
+}
+
+__attribute__((no_builtin("strlen"))) size_t _strlen(const char *str) {
+  const char *end = str;
+  while (*end)
+    ++end;
+  return static_cast<size_t>(end - str);
+}
+
+// Semihosting helpers
+int semihost_errno_negative() {
+  int error = semihosting_call(SYS_ERRNO, nullptr);
+  return error > 0 ? -error : -EIO;
+}
+
+off_t semihost_file_length(size_t handle) {
+  size_t args[] = {handle};
+  off_t length = semihosting_call(SYS_FLEN, args);
+  return length < 0 ? semihost_errno_negative() : length;
+}
+
+ssize_t semihost_read(size_t handle, char *buf, size_t size) {
   size_t args[] = {
-      reinterpret_cast<size_t>(std_stream_name),
+      handle,
+      reinterpret_cast<size_t>(buf),
+      size,
+  };
+  ssize_t not_read = semihosting_call(SYS_READ, args);
+  return not_read < 0 ? semihost_errno_negative()
+                      : static_cast<ssize_t>(size) - not_read;
+}
+
+ssize_t semihost_read_console(char *buf, size_t size) {
+  for (size_t i = 0; i < size; ++i) {
+    long ch = semihosting_call(SYS_READC, nullptr);
+    buf[i] = static_cast<char>(ch & 0xff);
+    if (buf[i] == '\r')
+      buf[i] = '\n';
+  }
+  return static_cast<ssize_t>(size);
+}
+
+ssize_t semihost_write(size_t handle, const char *buf, size_t size) {
+  size_t args[] = {
+      handle,
+      reinterpret_cast<size_t>(buf),
+      size,
+  };
+  ssize_t not_written = semihosting_call(SYS_WRITE, args);
+  return not_written < 0 ? semihost_errno_negative()
+                         : static_cast<ssize_t>(size) - not_written;
+}
+
+int semihost_seek(size_t handle, off_t position) {
+  size_t args[] = {
+      handle,
+      static_cast<size_t>(position),
+  };
+  return semihosting_call(SYS_SEEK, args) == 0 ? 0 : semihost_errno_negative();
+}
+
+long semihost_open(const char *path, size_t length, size_t mode) {
+  size_t args[] = {
+      reinterpret_cast<size_t>(path),
       mode,
-      sizeof(std_stream_name) - 1UL,
+      length,
   };
-  cookie->handle = semihosting_call(SYS_OPEN, args);
+  long handle = semihosting_call(SYS_OPEN, args);
+  return handle < 0 ? semihost_errno_negative() : handle;
+}
+
+int semihost_close(size_t handle) {
+  size_t args[] = {handle};
+  return semihosting_call(SYS_CLOSE, args);
 }
+
+void stdio_cookie_open(struct __llvm_libc_stdio_cookie *cookie, size_t mode) {
+  const char std_stream_name[] = ":tt";
+  cookie->handle = static_cast<size_t>(
+      semihost_open(std_stream_name, sizeof(std_stream_name) - 1, mode));
+}
+
 } // namespace
 
 extern "C" {
@@ -55,41 +194,105 @@ void __llvm_libc_exit(int status) {
   semihosting_call_exit(status);
 }
 
-struct __llvm_libc_stdio_cookie __llvm_libc_stdin_cookie;
-struct __llvm_libc_stdio_cookie __llvm_libc_stdout_cookie;
-struct __llvm_libc_stdio_cookie __llvm_libc_stderr_cookie;
+ssize_t __llvm_libc_stdio_read(void *cookie, char *buf, size_t size) {
+  if (cookie == &__llvm_libc_stdin_cookie)
+    return semihost_read_console(buf, size);
+  if (is_std_stream(cookie))
+    return -EBADF;
+
+  ssize_t result = semihost_read(get_handle(cookie), buf, size);
+  if (result < 0)
+    return result;
+  advance_file_position(cookie, static_cast<size_t>(result));
+  return result;
+}
 
-// Currently only supports reading from stdin.
-// We use SYS_READC for reading from stdin as QEMUs SYS_READ does not block.
-// For other files SYS_READ should be used as SYS_READC is intended for console
-// input and may block indefinitely in QEMU.
-// TODO: Extend to handle regular files when implemented in LLVM libc.
+ssize_t __llvm_libc_stdio_write(void *cookie, const char *buf, size_t size) {
+  ssize_t result = semihost_write(get_handle(cookie), buf, size);
+  if (result < 0)
+    return result;
+  if (!is_std_stream(cookie))
+    advance_file_position(cookie, static_cast<size_t>(result));
+  return result;
+}
 
-ssize_t __llvm_libc_stdio_read(struct __llvm_libc_stdio_cookie *cookie,
-                               char *buf, size_t size) {
-  if (cookie != &__llvm_libc_stdin_cookie)
-    return -1;
-  
-  for (size_t i = 0; i < size; ++i) {
-    long ch = semihosting_call(SYS_READC, nullptr);
-    buf[i] = static_cast<char>(ch & 0xff);
-    if (buf[i] == '\r')
-      buf[i] = '\n';
+int __llvm_libc_stdio_open(const char *path, const char *mode, void **cookie) {
+  auto *file_cookie = allocate_file();
+  if (!file_cookie)
+    return -EMFILE;
+
+  size_t open_mode = OPENMODE_R;
+  if (mode[0] == 'w')
+    open_mode = OPENMODE_W;
+  else if (mode[0] == 'a')
+    open_mode = OPENMODE_A;
+  for (const char *option = mode + 1; *option != '\0'; ++option) {
+    if (*option == '+')
+      open_mode |= OPENMODE_PLUS;
+    else if (*option == 'b')
+      open_mode |= OPENMODE_B;
+  }
+
+  long handle = semihost_open(path, _strlen(path), open_mode);
+  if (handle < 0) {
+    release_file(file_cookie);
+    return static_cast<int>(handle);
   }
-  return size;
+  file_cookie->stdio_cookie.handle = static_cast<size_t>(handle);
+  if (mode[0] == 'a') {
+    off_t length = semihost_file_length(get_handle(file_cookie));
+    if (length < 0) {
+      semihost_close(get_handle(file_cookie));
+      release_file(file_cookie);
+      return static_cast<int>(length);
+    }
+    set_file_position(file_cookie, length);
+  }
+  *cookie = file_cookie;
+  return 0;
 }
 
-ssize_t __llvm_libc_stdio_write(struct __llvm_libc_stdio_cookie *cookie,
-                                const char *buf, size_t size) {
-  size_t args[] = {
-      static_cast<size_t>(cookie->handle),
-      reinterpret_cast<size_t>(buf),
-      size,
-  };
-  ssize_t retval = semihosting_call(SYS_WRITE, args);
-  if (retval >= 0)
-    retval = size - retval;
-  return retval;
+off_t __llvm_libc_stdio_seek(void *cookie, off_t offset, int whence) {
+  if (is_std_stream(cookie))
+    return -ESPIPE;
+
+  off_t base;
+  if (whence == SEEK_SET)
+    base = 0;
+  else if (whence == SEEK_CUR)
+    base = get_file_position(cookie);
+  else if (whence == SEEK_END) {
+    base = semihost_file_length(get_handle(cookie));
+    if (base < 0)
+      return base;
+  } else
+    return -EINVAL;
+
+  off_t position = base + offset;
+  if (position < 0)
+    return -EINVAL;
+  int error = semihost_seek(get_handle(cookie), position);
+  if (error)
+    return error;
+  set_file_position(cookie, position);
+  return position;
+}
+
+int __llvm_libc_stdio_set_buffer(void *, char *, size_t, int) {
+  // Semihost streams are unbuffered.
+  return 0;
+}
+
+int __llvm_libc_stdio_flush(void *) {
+  // Semihost streams are unbuffered.
+  return 0;
+}
+
+int __llvm_libc_stdio_close(void *cookie) {
+  int result = semihost_close(get_handle(cookie));
+  if (!is_std_stream(cookie))
+    release_file(cookie);
+  return result;
 }
 
 bool __llvm_libc_timespec_get_active(struct timespec *ts) {
@@ -114,9 +317,9 @@ bool __llvm_libc_timespec_get_utc(struct timespec *ts) {
 
 // Entry point
 void _platform_init(void) {
-  stdio_open(&__llvm_libc_stdin_cookie, OPENMODE_R);
-  stdio_open(&__llvm_libc_stdout_cookie, OPENMODE_W);
-  stdio_open(&__llvm_libc_stderr_cookie, OPENMODE_W);
+  stdio_cookie_open(&__llvm_libc_stdin_cookie, OPENMODE_R);
+  stdio_cookie_open(&__llvm_libc_stdout_cookie, OPENMODE_W);
+  stdio_cookie_open(&__llvm_libc_stderr_cookie, OPENMODE_W);
 }
 
 // Debug output
@@ -135,21 +338,6 @@ void _platform_debug_putc(int c) {
 // - Escape sequences: \ copies next char as-is unless inside ' quotes
 //   or at the end of the string.
 
-// Helper functions implemented here to avoid dependency on libc which is not
-// available in LLVM libc hermetic testing.
-static int _isspace(char ch) {
-  return ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n' || ch == '\v' ||
-         ch == '\f';
-}
-
-__attribute__((no_builtin("strlen"))) static size_t _strlen(const char *str) {
-  const char *pend = str;
-  while (*pend) {
-    pend++;
-  }
-  return (size_t)(pend - str);
-}
-
 static inline void skip_spaces(const char *&p) {
   while (_isspace(*p))
     ++p;
diff --git a/arm-software/embedded/llvmlibc-support/semihost/semihost.h b/arm-software/embedded/llvmlibc-support/semihost/semihost.h
index d21ee2ecdaa3..600b78fb0cca 100644
--- a/arm-software/embedded/llvmlibc-support/semihost/semihost.h
+++ b/arm-software/embedded/llvmlibc-support/semihost/semihost.h
@@ -13,6 +13,8 @@
 #ifndef LLVMET_LLVMLIBC_SUPPORT_SEMIHOST_H
 #define LLVMET_LLVMLIBC_SUPPORT_SEMIHOST_H
 
+#include <llvm-libc-types/off_t.h>
+#include <llvm-libc-types/size_t.h>
 #include <llvm-libc-types/ssize_t.h>
 #include <stdint.h>
 
@@ -112,6 +114,22 @@ inline constexpr uint32_t OPENMODE_B = 1;
 inline constexpr uint32_t OPENMODE_PLUS = 2;
 } // namespace
 
-struct __llvm_libc_stdio_cookie { int handle; };
+struct __llvm_libc_stdio_cookie {
+  size_t handle;
+};
+
+struct __llvm_libc_semihost_file_cookie {
+  __llvm_libc_stdio_cookie stdio_cookie;
+  bool in_use;
+  off_t position;
+};
+
+struct __llvm_libc_semihost_file_cookie_pool {
+  __llvm_libc_semihost_file_cookie *cookies;
+  size_t size;
+};
+
+extern "C" __llvm_libc_semihost_file_cookie_pool
+    __llvm_libc_semihost_file_cookie_storage;
 
 #endif // LLVMET_LLVMLIBC_SUPPORT_SEMIHOST_H
diff --git a/libc/config/baremetal/aarch64/entrypoints.txt b/libc/config/baremetal/aarch64/entrypoints.txt
index 6c9733799f01..255bbf577ffa 100644
--- a/libc/config/baremetal/aarch64/entrypoints.txt
+++ b/libc/config/baremetal/aarch64/entrypoints.txt
@@ -128,14 +128,22 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.feof
     libc.src.stdio.ferror
     libc.src.stdio.fflush
+    libc.src.stdio.fclose
     libc.src.stdio.fgetc
     libc.src.stdio.fgets
     libc.src.stdio.fprintf
     libc.src.stdio.fputc
     libc.src.stdio.fputs
+    libc.src.stdio.fopen
     libc.src.stdio.fread
     libc.src.stdio.fscanf
     libc.src.stdio.fwrite
+    libc.src.stdio.fseek
+    libc.src.stdio.fseeko
+    libc.src.stdio.ftell
+    libc.src.stdio.ftello
+    libc.src.stdio.setbuf
+    libc.src.stdio.setvbuf
     libc.src.stdio.getc
     libc.src.stdio.getchar
     libc.src.stdio.printf
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
index a6b0dc50d030..81b1cb90687c 100644
--- a/libc/config/baremetal/arm/entrypoints.txt
+++ b/libc/config/baremetal/arm/entrypoints.txt
@@ -128,14 +128,22 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.stdio.feof
     libc.src.stdio.ferror
     libc.src.stdio.fflush
+    libc.src.stdio.fclose
     libc.src.stdio.fgetc
     libc.src.stdio.fgets
     libc.src.stdio.fprintf
     libc.src.stdio.fputc
     libc.src.stdio.fputs
+    libc.src.stdio.fopen
     libc.src.stdio.fread
     libc.src.stdio.fscanf
     libc.src.stdio.fwrite
+    libc.src.stdio.fseek
+    libc.src.stdio.fseeko
+    libc.src.stdio.ftell
+    libc.src.stdio.ftello
+    libc.src.stdio.setbuf
+    libc.src.stdio.setvbuf
     libc.src.stdio.getc
     libc.src.stdio.getchar
     libc.src.stdio.printf
diff --git a/libc/src/__support/OSUtil/baremetal/io.h b/libc/src/__support/OSUtil/baremetal/io.h
index 5e691f26060e..bb270b4b7b6e 100644
--- a/libc/src/__support/OSUtil/baremetal/io.h
+++ b/libc/src/__support/OSUtil/baremetal/io.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_BAREMETAL_IO_H
 #define LLVM_LIBC_SRC___SUPPORT_OSUTIL_BAREMETAL_IO_H
 
+#include "include/llvm-libc-types/off_t.h"
 #include "include/llvm-libc-types/size_t.h"
 #include "include/llvm-libc-types/ssize_t.h"
 #include "src/__support/CPP/string_view.h"
@@ -47,10 +48,36 @@ namespace LIBC_NAMESPACE_DECL {
 
 struct __llvm_libc_stdio_cookie;
 
+// On success, store a non-null application-owned cookie in `cookie` and return
+// 0. On failure, return a negative errno value.
+extern "C" int __llvm_libc_stdio_open(const char *path, const char *mode,
+                                      void **cookie);
+
+// Return the number of bytes read, which can be less than `size` and is zero at
+// end-of-file. On failure, return a negative errno value.
 extern "C" ssize_t __llvm_libc_stdio_read(void *cookie, char *buf, size_t size);
+
+// Return the number of bytes written, which can be less than `size`. On
+// failure, return a negative errno value.
 extern "C" ssize_t __llvm_libc_stdio_write(void *cookie, const char *buf,
                                            size_t size);
 
+// Return the resulting absolute file position on success. On failure, return a
+// negative errno value.
+extern "C" off_t __llvm_libc_stdio_seek(void *cookie, off_t offset, int whence);
+
+// Configure buffering for `cookie`. Return 0 on success or nonzero on failure,
+// matching setvbuf. The application owns any supplied buffer.
+extern "C" int __llvm_libc_stdio_set_buffer(void *cookie, char *buffer,
+                                            size_t size, int mode);
+
+// Flush buffered output for `cookie`, or all output streams if `cookie` is
+// null. Return 0 on success or EOF on failure, matching fflush.
+extern "C" int __llvm_libc_stdio_flush(void *cookie);
+
+// Return 0 on success or EOF on failure, matching fclose.
+extern "C" int __llvm_libc_stdio_close(void *cookie);
+
 void write_to_stderr(cpp::string_view msg);
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/CMakeLists.txt b/libc/src/stdio/CMakeLists.txt
index 68ee57fae646..c4db9834e7ce 100644
--- a/libc/src/stdio/CMakeLists.txt
+++ b/libc/src/stdio/CMakeLists.txt
@@ -67,32 +67,6 @@ add_entrypoint_object(
     libc.src.__support.File.file
 )
 
-add_entrypoint_object(
-  setbuf
-  SRCS
-    setbuf.cpp
-  HDRS
-    setbuf.h
-  DEPENDS
-    libc.src.errno.errno
-    libc.hdr.types.off_t
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
-add_entrypoint_object(
-  setvbuf
-  SRCS
-    setvbuf.cpp
-  HDRS
-    setvbuf.h
-  DEPENDS
-    libc.src.errno.errno
-    libc.hdr.types.FILE
-    libc.src.__support.File.file
-    libc.src.__support.File.platform_file
-)
-
 add_entrypoint_object(
   sscanf
   SRCS
@@ -274,6 +248,8 @@ add_stdio_entrypoint_object(ftell)
 add_stdio_entrypoint_object(fseeko)
 add_stdio_entrypoint_object(fileno)
 add_stdio_entrypoint_object(ftello)
+add_stdio_entrypoint_object(setbuf)
+add_stdio_entrypoint_object(setvbuf)
 add_stdio_entrypoint_object(fflush)
 add_stdio_entrypoint_object(clearerr)
 add_stdio_entrypoint_object(clearerr_unlocked)
diff --git a/libc/src/stdio/baremetal/CMakeLists.txt b/libc/src/stdio/baremetal/CMakeLists.txt
index d26cdbb0f9d5..d0734d5531dd 100644
--- a/libc/src/stdio/baremetal/CMakeLists.txt
+++ b/libc/src/stdio/baremetal/CMakeLists.txt
@@ -10,6 +10,62 @@ add_object_library(
     libc.src.__support.OSUtil.osutil
 )
 
+add_entrypoint_object(
+  fopen
+  SRCS fopen.cpp
+  HDRS ../fopen.h
+  DEPENDS libc.hdr.errno_macros libc.src.__support.OSUtil.osutil libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  fclose
+  SRCS fclose.cpp
+  HDRS ../fclose.h
+  DEPENDS libc.src.__support.OSUtil.osutil
+)
+
+add_entrypoint_object(
+  fseek
+  SRCS fseek.cpp
+  HDRS ../fseek.h
+  DEPENDS libc.hdr.errno_macros libc.src.__support.OSUtil.osutil libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  ftell
+  SRCS ftell.cpp
+  HDRS ../ftell.h
+  DEPENDS libc.hdr.errno_macros libc.hdr.stdio_macros libc.src.__support.OSUtil.osutil libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  fseeko
+  SRCS fseeko.cpp
+  HDRS ../fseeko.h
+  DEPENDS libc.hdr.errno_macros libc.src.__support.OSUtil.osutil libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  ftello
+  SRCS ftello.cpp
+  HDRS ../ftello.h
+  DEPENDS libc.hdr.errno_macros libc.hdr.stdio_macros libc.src.__support.OSUtil.osutil libc.src.errno.errno
+)
+
+add_entrypoint_object(
+  setbuf
+  SRCS setbuf.cpp
+  HDRS ../setbuf.h
+  DEPENDS libc.hdr.stdio_macros libc.hdr.types.FILE libc.src.__support.OSUtil.osutil
+)
+
+add_entrypoint_object(
+  setvbuf
+  SRCS setvbuf.cpp
+  HDRS ../setvbuf.h
+  DEPENDS libc.hdr.types.FILE libc.src.__support.OSUtil.osutil
+)
+
 add_header_library(
   vfprintf_internal
   HDRS
@@ -98,6 +154,7 @@ add_entrypoint_object(
     ../fflush.h
   DEPENDS
     .file_internal
+    libc.src.__support.OSUtil.osutil
 )
 
 add_entrypoint_object(
diff --git a/libc/src/stdio/baremetal/fclose.cpp b/libc/src/stdio/baremetal/fclose.cpp
new file mode 100644
index 000000000000..2714a11c681c
--- /dev/null
+++ b/libc/src/stdio/baremetal/fclose.cpp
@@ -0,0 +1,12 @@
+#include "src/stdio/fclose.h"
+
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, fclose, (::FILE * stream)) {
+  return __llvm_libc_stdio_close(stream);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/fflush.cpp b/libc/src/stdio/baremetal/fflush.cpp
index 4a39c25ae11c..136e98cc7dae 100644
--- a/libc/src/stdio/baremetal/fflush.cpp
+++ b/libc/src/stdio/baremetal/fflush.cpp
@@ -8,15 +8,13 @@
 
 #include "src/stdio/fflush.h"
 
+#include "src/__support/OSUtil/io.h"
 #include "src/__support/common.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-// Baremetal uses unbuffered I/O, so there is nothing to flush.
 LLVM_LIBC_FUNCTION(int, fflush, (::FILE * stream)) {
-  (void)stream;
-  // TODO: Shall we have an embedding API for fflush?
-  return 0;
+  return __llvm_libc_stdio_flush(stream);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/fopen.cpp b/libc/src/stdio/baremetal/fopen.cpp
new file mode 100644
index 000000000000..1d7cfe98f2cb
--- /dev/null
+++ b/libc/src/stdio/baremetal/fopen.cpp
@@ -0,0 +1,25 @@
+#include "src/stdio/fopen.h"
+
+#include "hdr/errno_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(::FILE *, fopen,
+                   (const char *__restrict path, const char *__restrict mode)) {
+  if (path == nullptr || mode == nullptr || mode[0] == '\0') {
+    libc_errno = EINVAL;
+    return nullptr;
+  }
+  void *cookie = nullptr;
+  int result = __llvm_libc_stdio_open(path, mode, &cookie);
+  if (result != 0 || cookie == nullptr) {
+    libc_errno = result != 0 ? -result : EINVAL;
+    return nullptr;
+  }
+  return reinterpret_cast<::FILE *>(cookie);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/fseek.cpp b/libc/src/stdio/baremetal/fseek.cpp
new file mode 100644
index 000000000000..f7db74786fd3
--- /dev/null
+++ b/libc/src/stdio/baremetal/fseek.cpp
@@ -0,0 +1,23 @@
+#include "src/stdio/fseek.h"
+
+#include "hdr/errno_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, fseek, (::FILE * stream, long offset, int whence)) {
+  if (stream == nullptr) {
+    libc_errno = EINVAL;
+    return -1;
+  }
+  off_t result = __llvm_libc_stdio_seek(stream, offset, whence);
+  if (result < 0) {
+    libc_errno = static_cast<int>(-result);
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/fseeko.cpp b/libc/src/stdio/baremetal/fseeko.cpp
new file mode 100644
index 000000000000..c5b32b1158e1
--- /dev/null
+++ b/libc/src/stdio/baremetal/fseeko.cpp
@@ -0,0 +1,31 @@
+//===-- Implementation of fseeko for baremetal -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/fseeko.h"
+
+#include "hdr/errno_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, fseeko, (::FILE * stream, off_t offset, int whence)) {
+  if (stream == nullptr) {
+    libc_errno = EINVAL;
+    return -1;
+  }
+  off_t result = __llvm_libc_stdio_seek(stream, offset, whence);
+  if (result < 0) {
+    libc_errno = static_cast<int>(-result);
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/ftell.cpp b/libc/src/stdio/baremetal/ftell.cpp
new file mode 100644
index 000000000000..7ebb4d059622
--- /dev/null
+++ b/libc/src/stdio/baremetal/ftell.cpp
@@ -0,0 +1,24 @@
+#include "src/stdio/ftell.h"
+
+#include "hdr/errno_macros.h"
+#include "hdr/stdio_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(long, ftell, (::FILE * stream)) {
+  if (stream == nullptr) {
+    libc_errno = EINVAL;
+    return -1;
+  }
+  off_t result = __llvm_libc_stdio_seek(stream, 0, SEEK_CUR);
+  if (result < 0) {
+    libc_errno = static_cast<int>(-result);
+    return -1;
+  }
+  return static_cast<long>(result);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/ftello.cpp b/libc/src/stdio/baremetal/ftello.cpp
new file mode 100644
index 000000000000..84ae74a72da7
--- /dev/null
+++ b/libc/src/stdio/baremetal/ftello.cpp
@@ -0,0 +1,32 @@
+//===-- Implementation of ftello for baremetal -----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/ftello.h"
+
+#include "hdr/errno_macros.h"
+#include "hdr/stdio_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(off_t, ftello, (::FILE * stream)) {
+  if (stream == nullptr) {
+    libc_errno = EINVAL;
+    return static_cast<off_t>(-1);
+  }
+  off_t result = __llvm_libc_stdio_seek(stream, 0, SEEK_CUR);
+  if (result < 0) {
+    libc_errno = static_cast<int>(-result);
+    return static_cast<off_t>(-1);
+  }
+  return result;
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/setbuf.cpp b/libc/src/stdio/baremetal/setbuf.cpp
new file mode 100644
index 000000000000..482f0ac43c75
--- /dev/null
+++ b/libc/src/stdio/baremetal/setbuf.cpp
@@ -0,0 +1,22 @@
+//===-- Bare-metal implementation of setbuf ------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/setbuf.h"
+#include "hdr/stdio_macros.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(void, setbuf,
+                   (::FILE *__restrict stream, char *__restrict buffer)) {
+  __llvm_libc_stdio_set_buffer(stream, buffer, BUFSIZ,
+                               buffer == nullptr ? _IONBF : _IOFBF);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/baremetal/setvbuf.cpp b/libc/src/stdio/baremetal/setvbuf.cpp
new file mode 100644
index 000000000000..4235230a10ef
--- /dev/null
+++ b/libc/src/stdio/baremetal/setvbuf.cpp
@@ -0,0 +1,21 @@
+//===-- Bare-metal implementation of setvbuf -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdio/setvbuf.h"
+#include "src/__support/OSUtil/io.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, setvbuf,
+                   (::FILE *__restrict stream, char *__restrict buffer,
+                    int mode, size_t size)) {
+  return __llvm_libc_stdio_set_buffer(stream, buffer, size, mode);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/stdio/generic/CMakeLists.txt b/libc/src/stdio/generic/CMakeLists.txt
index b6bb41b5053a..3df8ab501c4a 100644
--- a/libc/src/stdio/generic/CMakeLists.txt
+++ b/libc/src/stdio/generic/CMakeLists.txt
@@ -10,6 +10,32 @@ function(add_generic_entrypoint_object name)
   endif()
 endfunction()
 
+add_generic_entrypoint_object(
+  setbuf
+  SRCS
+    ../setbuf.cpp
+  HDRS
+    ../setbuf.h
+  DEPENDS
+    libc.src.errno.errno
+    libc.hdr.types.off_t
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
+add_generic_entrypoint_object(
+  setvbuf
+  SRCS
+    ../setvbuf.cpp
+  HDRS
+    ../setvbuf.h
+  DEPENDS
+    libc.src.errno.errno
+    libc.hdr.types.FILE
+    libc.src.__support.File.file
+    libc.src.__support.File.platform_file
+)
+
 add_generic_entrypoint_object(
   clearerr
   SRCS
diff --git a/libcxx/include/fstream b/libcxx/include/fstream
index c2296fe42729..fc06b2965b8c 100644
--- a/libcxx/include/fstream
+++ b/libcxx/include/fstream
@@ -192,7 +192,7 @@ typedef basic_fstream<wchar_t> wfstream;
 #  include <__config>
 
 // Downstream issue: #375 (Enable fstream independently of filesystem)
-#  if _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION || _LIBCPP_LIBC_NEWLIB
+#  if _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION || _LIBCPP_LIBC_NEWLIB || _LIBCPP_LIBC_LLVM_LIBC
 
 #    include <__algorithm/max.h>
 #    include <__assert>
@@ -242,6 +242,8 @@ public:
   using native_handle_type = void*; // HANDLE
 #      elif __has_include(<unistd.h>)
   using native_handle_type = int; // POSIX file descriptor
+#      elif _LIBCPP_LIBC_LLVM_LIBC
+  using native_handle_type = FILE*;
 #      else
 #        error "Provide a native file handle!"
 #      endif
@@ -278,6 +280,8 @@ public:
     return std::__filebuf_windows_native_handle(__file_);
 #      elif __has_include(<unistd.h>)
     return fileno(__file_);
+#      elif _LIBCPP_LIBC_LLVM_LIBC
+    return __file_;
 #      else
 #        error "Provide a way to determine the file native handle!"
 #      endif
@@ -1640,7 +1644,7 @@ _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
-#  endif // _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION
+#  endif // _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION || _LIBCPP_LIBC_NEWLIB || _LIBCPP_LIBC_LLVM_LIBC
 
 #endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
 
diff --git a/libcxx/src/ios.instantiations.cpp b/libcxx/src/ios.instantiations.cpp
index a6e56395617a..98d6f53f7802 100644
--- a/libcxx/src/ios.instantiations.cpp
+++ b/libcxx/src/ios.instantiations.cpp
@@ -58,7 +58,7 @@ template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ostringstream<char
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_istringstream<char>;
 
 // Downstream issue: #375 (Enable fstream independently of filesystem)
-#if _LIBCPP_HAS_FILESYSTEM || _LIBCPP_LIBC_NEWLIB
+#if _LIBCPP_HAS_FILESYSTEM || _LIBCPP_LIBC_NEWLIB || _LIBCPP_LIBC_LLVM_LIBC
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ifstream<char>;
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_ofstream<char>;
 template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS basic_filebuf<char>;