diff --git a/libc/bionic/strtol.cpp b/libc/bionic/strtol.cpp
new file mode 100644
index 0000000..f83a317
--- /dev/null
+++ b/libc/bionic/strtol.cpp
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 1992 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdlib.h>
+
+template <typename T, T Min, T Max> T StrToI(const char* nptr, char** endptr, int base) {
+  // Ensure that base is between 2 and 36 inclusive, or the special value of 0.
+  if (base < 0 || base == 1 || base > 36) {
+    if (endptr != nullptr) *endptr = const_cast<char*>(nptr);
+    errno = EINVAL;
+    return 0;
+  }
+
+  // Skip white space and pick up leading +/- sign if any.
+  // If base is 0, allow 0x for hex and 0 for octal, else
+  // assume decimal; if base is already 16, allow 0x.
+  const char* s = nptr;
+  int c;
+  do {
+    c = static_cast<unsigned char>(*s++);
+  } while (isspace(c));
+  int neg;
+  if (c == '-') {
+    neg = 1;
+    c = *s++;
+  } else {
+    neg = 0;
+    if (c == '+') c = *s++;
+  }
+  if ((base == 0 || base == 16) && c == '0' &&
+      (*s == 'x' || *s == 'X') && isxdigit(static_cast<unsigned char>(s[1]))) {
+    c = s[1];
+    s += 2;
+    base = 16;
+  }
+  if (base == 0) base = (c == '0') ? 8 : 10;
+
+  // Compute the cutoff value between legal numbers and illegal
+  // numbers.  That is the largest legal value, divided by the
+  // base.  An input number that is greater than this value, if
+  // followed by a legal input character, is too big.  One that
+  // is equal to this value may be valid or not; the limit
+  // between valid and invalid numbers is then based on the last
+  // digit.  For instance, if the range for intmax_t is
+  // [-9223372036854775808..9223372036854775807] and the input base
+  // is 10, cutoff will be set to 922337203685477580 and cutlim to
+  // either 7 (neg==0) or 8 (neg==1), meaning that if we have
+  // accumulated a value > 922337203685477580, or equal but the
+  // next digit is > 7 (or 8), the number is too big, and we will
+  // return a range error.
+  T cutoff = neg ? Min : Max;
+  int cutlim = cutoff % base;
+  cutoff /= base;
+  if (neg) {
+    if (cutlim > 0) {
+      cutlim -= base;
+      cutoff += 1;
+    }
+    cutlim = -cutlim;
+  }
+
+  // Set `any` if any digits consumed; make it negative to indicate overflow.
+  int any = 0;
+  T acc = 0;
+  for (; ; c = static_cast<unsigned char>(*s++)) {
+    if (isdigit(c)) {
+      c -= '0';
+    } else if (isalpha(c)) {
+      c -= isupper(c) ? 'A' - 10 : 'a' - 10;
+    } else {
+      break;
+    }
+    if (c >= base) break;
+    if (any < 0) continue;
+    if (neg) {
+      if (acc < cutoff || (acc == cutoff && c > cutlim)) {
+        any = -1;
+        acc = Min;
+        errno = ERANGE;
+      } else {
+        any = 1;
+        acc *= base;
+        acc -= c;
+      }
+    } else {
+      if (acc > cutoff || (acc == cutoff && c > cutlim)) {
+        any = -1;
+        acc = Max;
+        errno = ERANGE;
+      } else {
+        any = 1;
+        acc *= base;
+        acc += c;
+      }
+    }
+  }
+  if (endptr != nullptr) *endptr = const_cast<char*>(any ? s - 1 : nptr);
+  return acc;
+}
+
+template <typename T, T Max> T StrToU(const char* nptr, char** endptr, int base) {
+  if (base < 0 || base == 1 || base > 36) {
+    if (endptr != nullptr) *endptr = const_cast<char*>(nptr);
+    errno = EINVAL;
+    return 0;
+  }
+
+  const char* s = nptr;
+  int c;
+  do {
+    c = static_cast<unsigned char>(*s++);
+  } while (isspace(c));
+  int neg;
+  if (c == '-') {
+    neg = 1;
+    c = *s++;
+  } else {
+    neg = 0;
+    if (c == '+') c = *s++;
+  }
+  if ((base == 0 || base == 16) && c == '0' &&
+      (*s == 'x' || *s == 'X') && isxdigit(static_cast<unsigned char>(s[1]))) {
+    c = s[1];
+    s += 2;
+    base = 16;
+  }
+  if (base == 0) base = (c == '0') ? 8 : 10;
+
+  T cutoff = Max / static_cast<T>(base);
+  int cutlim = Max % static_cast<T>(base);
+  T acc = 0;
+  int any = 0;
+  for (; ; c = static_cast<unsigned char>(*s++)) {
+    if (isdigit(c)) {
+      c -= '0';
+    } else if (isalpha(c)) {
+      c -= isupper(c) ? 'A' - 10 : 'a' - 10;
+    } else {
+      break;
+    }
+    if (c >= base) break;
+    if (any < 0) continue;
+    if (acc > cutoff || (acc == cutoff && c > cutlim)) {
+      any = -1;
+      acc = Max;
+      errno = ERANGE;
+    } else {
+      any = 1;
+      acc *= static_cast<T>(base);
+      acc += c;
+    }
+  }
+  if (neg && any > 0) acc = -acc;
+  if (endptr != nullptr) *endptr = const_cast<char*>(any ? s - 1 : nptr);
+  return acc;
+}
+
+int atoi(const char* s) {
+  return strtol(s, nullptr, 10);
+}
+
+long atol(const char* s) {
+  return strtol(s, nullptr, 10);
+}
+
+long long atoll(const char* s) {
+  return strtoll(s, nullptr, 10);
+}
+
+intmax_t strtoimax(const char* s, char** end, int base) {
+  return StrToI<intmax_t, INTMAX_MIN, INTMAX_MAX>(s, end, base);
+}
+
+long strtol(const char* s, char** end, int base) {
+  return StrToI<long, LONG_MIN, LONG_MAX>(s, end, base);
+}
+
+long long strtoll(const char* s, char** end, int base) {
+  return StrToI<long long, LLONG_MIN, LLONG_MAX>(s, end, base);
+}
+
+// Public API since L, but not in any header.
+extern "C" long long strtoq(const char* s, char** end, int base) {
+  return strtoll(s, end, base);
+}
+
+unsigned long strtoul(const char* s, char** end, int base) {
+  return StrToU<unsigned long, ULONG_MAX>(s, end, base);
+}
+
+unsigned long long strtoull(const char* s, char** end, int base) {
+  return StrToU<unsigned long long, ULLONG_MAX>(s, end, base);
+}
+
+uintmax_t strtoumax(const char* s, char** end, int base) {
+  return StrToU<uintmax_t, UINTMAX_MAX>(s, end, base);
+}
+
+// Public API since L, but not in any header.
+extern "C" unsigned long long strtouq(const char* s, char** end, int base) {
+  return strtoull(s, end, base);
+}