diff --git a/Userland/Libraries/LibC/stdlib.cpp b/Userland/Libraries/LibC/stdlib.cpp
index d56dfc03d1..d9e7d73ead 100644
--- a/Userland/Libraries/LibC/stdlib.cpp
+++ b/Userland/Libraries/LibC/stdlib.cpp
@@ -24,8 +24,11 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/internals.h>
+#include <sys/ioctl.h>
+#include <sys/ioctl_numbers.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
+#include <sys/sysmacros.h>
 #include <sys/wait.h>
 #include <syscall.h>
 #include <unistd.h>
@@ -724,8 +727,39 @@ char* ptsname(int fd)
 
 int ptsname_r(int fd, char* buffer, size_t size)
 {
-    int rc = syscall(SC_ptsname, fd, buffer, size);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
+    struct stat stat;
+    if (fstat(fd, &stat) < 0)
+        return -1;
+
+    StringBuilder devpts_path_builder;
+    devpts_path_builder.append("/dev/pts/"sv);
+
+    int master_pty_index = 0;
+    // Note: When the user opens a PTY from /dev/ptmx with posix_openpt(), the open file descriptor
+    // points to /dev/ptmx, (major number is 5 and minor number is 2), but internally
+    // in the kernel, it points to a new MasterPTY device. When we do ioctl with TIOCGPTN option
+    // on the open file descriptor, it actually asks the MasterPTY what is the assigned index
+    // of it when the PTYMultiplexer created it.
+    if (ioctl(fd, TIOCGPTN, &master_pty_index) < 0)
+        return -1;
+
+    if (master_pty_index < 0) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    devpts_path_builder.appendff("{:d}", master_pty_index);
+    if (devpts_path_builder.length() > size) {
+        errno = ERANGE;
+        return -1;
+    }
+    memset(buffer, 0, devpts_path_builder.length() + 1);
+    auto full_devpts_path_string = devpts_path_builder.build();
+    if (!full_devpts_path_string.copy_characters_to_buffer(buffer, size)) {
+        errno = ERANGE;
+        return -1;
+    }
+    return 0;
 }
 
 static unsigned long s_next_rand = 1;
diff --git a/Userland/Libraries/LibC/unistd.cpp b/Userland/Libraries/LibC/unistd.cpp
index b05f7e62e8..c7caea4678 100644
--- a/Userland/Libraries/LibC/unistd.cpp
+++ b/Userland/Libraries/LibC/unistd.cpp
@@ -4,12 +4,14 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <AK/ScopeGuard.h>
 #include <AK/ScopedValueRollback.h>
 #include <AK/String.h>
 #include <AK/Vector.h>
 #include <alloca.h>
 #include <assert.h>
 #include <bits/pthread_integration.h>
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <getopt.h>
@@ -22,6 +24,8 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/select.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
 #include <sys/types.h>
 #include <syscall.h>
 #include <termios.h>
@@ -398,11 +402,72 @@ ssize_t pwrite(int fd, const void* buf, size_t count, off_t offset)
     return nwritten;
 }
 
+// Note: Be sure to send to directory_name parameter a directory name ended with trailing slash.
+static int ttyname_r_for_directory(const char* directory_name, dev_t device_mode, ino_t inode_number, char* buffer, size_t size)
+{
+    DIR* dirstream = opendir(directory_name);
+    if (!dirstream) {
+        return -1;
+    }
+
+    auto close_dir_stream_on_exit = ScopeGuard([dirstream] {
+        closedir(dirstream);
+    });
+
+    struct dirent* entry = nullptr;
+    char* name_path = nullptr;
+
+    // FIXME: Use LibCore DirIterator here instead
+    while ((entry = readdir(dirstream)) != nullptr) {
+        if (((ino_t)entry->d_ino == inode_number)
+            && strcmp(entry->d_name, "stdin")
+            && strcmp(entry->d_name, "stdout")
+            && strcmp(entry->d_name, "stderr")) {
+
+            size_t name_length = strlen(directory_name) + strlen(entry->d_name) + 1;
+
+            if (name_length > size) {
+                errno = ERANGE;
+                return -1;
+            }
+
+            name_path = (char*)malloc(name_length);
+            memset(name_path, 0, name_length);
+            memcpy(name_path, directory_name, strlen(directory_name));
+            memcpy(&name_path[strlen(directory_name)], entry->d_name, strlen(entry->d_name));
+            struct stat st;
+            if (lstat(name_path, &st) < 0) {
+                free(name_path);
+                continue;
+            }
+
+            if (device_mode == st.st_rdev) {
+                memset(buffer, 0, name_length);
+                memcpy(buffer, name_path, name_length);
+                free(name_path);
+                return 0;
+            }
+        }
+    }
+    free(name_path);
+    return -1;
+}
+
 // https://pubs.opengroup.org/onlinepubs/9699919799/functions/ttyname_r.html
 int ttyname_r(int fd, char* buffer, size_t size)
 {
-    int rc = syscall(SC_ttyname, fd, buffer, size);
-    __RETURN_WITH_ERRNO(rc, rc, -1);
+    struct stat stat;
+    if (fstat(fd, &stat) < 0)
+        return -1;
+    dev_t major_minor_numbers = stat.st_rdev;
+    ino_t inode_number = stat.st_ino;
+    if (ttyname_r_for_directory("/dev/", major_minor_numbers, inode_number, buffer, size) < 0) {
+        if (ttyname_r_for_directory("/dev/pts/", major_minor_numbers, inode_number, buffer, size) < 0) {
+            errno = ENOTTY;
+            return -1;
+        }
+    }
+    return 0;
 }
 
 static char ttyname_buf[32];