diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2b8b274..024f37c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -25,7 +25,7 @@ set(CMAKE_EXE_LINKER_FLAGS
 
 set(malloc_impl dlmalloc)
 set(photon_libc_sources "")
-set(generic_dirs string stdio stdlib errno internal)
+set(generic_dirs string stdio stdlib errno internal ctype)
 
 message(STATUS "Memory allocator: ${malloc_impl}")
 
diff --git a/photon/libc/ctype/ctype.c b/photon/libc/ctype/ctype.c
new file mode 100644
index 0000000..1aaba3e
--- /dev/null
+++ b/photon/libc/ctype/ctype.c
@@ -0,0 +1,46 @@
+#include <stdbool.h>
+
+static unsigned int random_seed = 53455346;
+
+int isupper(int c) { return (c >= 65 && c <= 90); }
+
+int islower(int c) { return (c >= 97 && c <= 122); }
+
+int toupper(int c) {
+    if (!islower(c)) {
+        return c;
+    }
+
+    return c - 32;
+}
+
+int tolower(int c) {
+    if (!isupper(c)) {
+        return c;
+    }
+
+    return c + 32;
+}
+
+int isdigit(int c) { return (c >= 48 && c <= 57); }
+
+int isalpha(int c) { return (c >= 65 && c <= 90) || (c >= 97 && c <= 122); }
+
+int isalnum(int c) { return isalpha(c) | isdigit(c); }
+
+int iscntrl(int c) { return (c <= 31) || (c == 127); }
+
+int isprint(int c) { return (c >= 32 && c <= 126) || (c >= 128 && c <= 254); }
+
+int isgraph(int c) { return isprint(c) && c != 32; }
+
+int ispunct(int c) { return isgraph(c) && !isalnum(c); }
+
+int isspace(int c) {
+    return (c == ' ') || (c == '\t') || (c == '\n') || (c == '\v') ||
+           (c == '\f') || (c == '\r');
+}
+
+int isxdigit(int c) {
+    return isdigit(c) || (c >= 65 && c <= 70) || (c >= 97 && c <= 102);
+}
diff --git a/photon/libc/include/ctype.h b/photon/libc/include/ctype.h
new file mode 100644
index 0000000..ef78c6f
--- /dev/null
+++ b/photon/libc/include/ctype.h
@@ -0,0 +1,27 @@
+#ifndef TYPES_H_
+#define TYPES_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern int isalnum(int c);
+extern int isalpha(int c);
+extern int iscntrl(int c);
+extern int isdigit(int c);
+extern int isgraph(int c);
+extern int islower(int c);
+extern int isprint(int c);
+extern int ispunct(int c);
+extern int isspace(int c);
+extern int isupper(int c);
+extern int isxdigit(int c);
+extern int tolower(int c);
+extern int toupper(int c);
+extern int fill_random(unsigned char *buffer, unsigned int size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/photon/libc/include/limits.h b/photon/libc/include/limits.h
new file mode 100644
index 0000000..1defa10
--- /dev/null
+++ b/photon/libc/include/limits.h
@@ -0,0 +1,24 @@
+#ifndef LIMITS_H_
+#define LIMITS_H_
+
+#define CHAR_BIT 8
+#define SCHAR_MIN -127
+#define SCHAR_MAX 127
+#define UCHAR_MAX 255
+#define CHAR_MIN SCHAR_MIN
+#define CHAR_MAX SCHAR_MAX
+#define MB_LEN_MAX 1
+#define SHRT_MIN -32767
+#define SHRT_MAX 32767
+#define USHRT_MAX 65535
+#define INT_MIN -2147483648
+#define INT_MAX 2147483648
+#define UINT_MAX 4294967295
+#define LONG_MIN -2147483648
+#define LONG_MAX 2147483648
+#define ULONG_MAX 4294967295
+#define _I64_MIN -9223372036854775808
+#define _I64_MAX 9223372036854775808
+#define _UI64_MAX 18446744073709551615
+
+#endif /* LIMITS_H_ */
diff --git a/photon/libc/include/stddef.h b/photon/libc/include/stddef.h
index 73c6622..a2525fc 100644
--- a/photon/libc/include/stddef.h
+++ b/photon/libc/include/stddef.h
@@ -4,7 +4,7 @@
 #include "machine/_stdint.h"
 
 #define NULL ((void *)0)
-#define offsetof(t, m) ((size_t)(&(t *)0)->m)
+#define offsetof(t, m) ((size_t)&(((t *)0)->m))
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/photon/libc/include/stdio.h b/photon/libc/include/stdio.h
index ef062c0..de4e4a8 100644
--- a/photon/libc/include/stdio.h
+++ b/photon/libc/include/stdio.h
@@ -29,13 +29,22 @@ extern FILE *stderr;
 
 extern FILE *fopen(const char *path, const char *mode);
 extern FILE *freopen(const char *path, const char *mode, FILE *fp);
+#ifdef __magenta__
+extern FILE *fdopen(mx_handle_t fd, const char *mode);
+#else
 extern FILE *fdopen(int fd, const char *mode);
+#endif
 extern int fclose(FILE *fp);
 extern int fflush(FILE *fp);
+extern size_t fread(void *ptr, size_t size, size_t count, FILE *fp);
+extern size_t fwrite(const void *ptr, size_t size, size_t count, FILE *fp);
 
 extern int fileno(FILE *fp);
 extern int fputs(const char *str, FILE *fp);
 extern int fputc(int c, FILE *fp);
+extern int fgetc(FILE *fp);
+
+extern int ungetc(int c, FILE *fp);
 
 extern int printf(const char *restrict format, ...);
 extern int fprintf(FILE *fp, const char *restrict format, ...);
diff --git a/photon/libc/include/stdlib.h b/photon/libc/include/stdlib.h
index 93b033f..a0d4ac7 100644
--- a/photon/libc/include/stdlib.h
+++ b/photon/libc/include/stdlib.h
@@ -12,6 +12,11 @@ extern _Noreturn void exit(int code);
 extern void *malloc(size_t sz);
 extern void free(void *ptr);
 
+extern int atoi(const char *str);
+extern double atof(const char *str);
+extern long int strtol(const char *str, char **endptr, int base);
+extern double strtod(const char *str, char **endptr);
+
 #if defined(__cplusplus)
 } /* extern "C" */
 #endif
diff --git a/photon/libc/include/string.h b/photon/libc/include/string.h
index b123a81..a0be36a 100644
--- a/photon/libc/include/string.h
+++ b/photon/libc/include/string.h
@@ -16,6 +16,11 @@ extern size_t strlen(const char *str);
 extern int strcmp(const char *a, const char *b);
 extern int strncmp(const char *a, const char *b, size_t sz);
 
+extern char *strcpy(char *dest, const char *src);
+extern char *strncpy(char *dest, const char *src, size_t sz);
+
+extern char *strdup(const char *s);
+
 #if defined(__cplusplus)
 } /* extern "C" */
 #endif
diff --git a/photon/libc/stdio/fdopen.c b/photon/libc/stdio/fdopen.c
index d379308..45bc696 100644
--- a/photon/libc/stdio/fdopen.c
+++ b/photon/libc/stdio/fdopen.c
@@ -1,10 +1,17 @@
 #include <stdio.h>
+#include <string.h>
 #include <stdlib.h>
 #include <__fio.h>
 
+#ifdef __magenta__
+FILE *fdopen(mx_handle_t fd, const char *mode)
+#else
 FILE *fdopen(int fd, const char *mode)
+#endif
 {
     struct __io_file *fp = malloc(sizeof(*fp));
+    memset(fp, 0x0, sizeof(*fp));
+
     int res = __fio_fdopen(fd, mode, fp);
     if (res != 0) {
         free(fp);
diff --git a/photon/libc/stdio/fgetc.c b/photon/libc/stdio/fgetc.c
new file mode 100644
index 0000000..7f37fb8
--- /dev/null
+++ b/photon/libc/stdio/fgetc.c
@@ -0,0 +1,13 @@
+#include <stdio.h>
+#include <__fio.h>
+
+int fgetc(FILE *fp)
+{
+    char ch = 0;
+    __fio_read(fp, &ch, 1);
+    if (__fio_error(fp)) {
+        return EOF;
+    }
+
+    return ch;
+}
diff --git a/photon/libc/stdio/fopen.c b/photon/libc/stdio/fopen.c
index e671015..0afe20c 100644
--- a/photon/libc/stdio/fopen.c
+++ b/photon/libc/stdio/fopen.c
@@ -1,10 +1,13 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <__fio.h>
 
 FILE *fopen(const char *path, const char *mode)
 {
     struct __io_file *fp = malloc(sizeof(*fp));
+    memset(fp, 0x0, sizeof(*fp));
+
     int res = __fio_fopen(path, mode, fp);
     if (res != 0) {
         free(fp);
diff --git a/photon/libc/stdio/fwrite.c b/photon/libc/stdio/fwrite.c
new file mode 100644
index 0000000..1afc42e
--- /dev/null
+++ b/photon/libc/stdio/fwrite.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <__fio.h>
+
+size_t fwrite(const void *ptr, size_t size, size_t count, FILE *fp)
+{
+    if (!size || !count) {
+        return 0;
+    }
+
+    unsigned int written = __fio_write(fp, ptr, size * count);
+    return written / size;
+}
diff --git a/photon/libc/stdio/ungetc.c b/photon/libc/stdio/ungetc.c
new file mode 100644
index 0000000..b8fdea0
--- /dev/null
+++ b/photon/libc/stdio/ungetc.c
@@ -0,0 +1,8 @@
+#include <stdio.h>
+#include <__fio.h>
+
+int ungetc(int c, FILE *fp)
+{
+    int res = __fio_ungetc(fp, c);
+    return res == -1 ? EOF : c;
+}
diff --git a/photon/libc/stdlib/atof.c b/photon/libc/stdlib/atof.c
new file mode 100644
index 0000000..1c909b1
--- /dev/null
+++ b/photon/libc/stdlib/atof.c
@@ -0,0 +1,42 @@
+#include <ctype.h>
+
+double atof(const char *s)
+{
+    double a = 0.0;
+    int e = 0;
+    int c;
+    while ((c = *s++) != '\0' && isdigit(c)) {
+        a = a*10.0 + (c - '0');
+    }
+    if (c == '.') {
+        while ((c = *s++) != '\0' && isdigit(c)) {
+            a = a*10.0 + (c - '0');
+            e = e-1;
+        }
+    }
+    if (c == 'e' || c == 'E') {
+        int sign = 1;
+        int i = 0;
+        c = *s++;
+        if (c == '+')
+            c = *s++;
+        else if (c == '-') {
+            c = *s++;
+            sign = -1;
+        }
+        while (isdigit(c)) {
+            i = i*10 + (c - '0');
+            c = *s++;
+        }
+        e += i*sign;
+    }
+    while (e > 0) {
+        a *= 10.0;
+        e--;
+    }
+    while (e < 0) {
+        a *= 0.1;
+        e++;
+    }
+    return a;
+}
diff --git a/photon/libc/stdlib/atoi.c b/photon/libc/stdlib/atoi.c
new file mode 100644
index 0000000..e69de29
diff --git a/photon/libc/stdlib/strtod.c b/photon/libc/stdlib/strtod.c
new file mode 100644
index 0000000..a88b4ec
--- /dev/null
+++ b/photon/libc/stdlib/strtod.c
@@ -0,0 +1,91 @@
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+double strtod(const char *str, char **ptr)
+{
+    if (ptr == (char **)0) {
+        return atof(str);
+    }
+
+    size_t len = strlen(str);
+    char rstr[len + 1];
+    strcpy(rstr, str);
+
+    char *p = rstr;
+
+    while (isspace(*p)) {
+        ++p;
+    }
+
+    if (*p == '+' || *p == '-') {
+        ++p;
+    }
+
+    if ((p[0] == 'i' || p[0] == 'I')
+            && (p[1] == 'n' || p[1] == 'N')
+            && (p[2] == 'f' || p[2] == 'F')) {
+        if ((p[3] == 'i' || p[3] == 'I')
+                && (p[4] == 'n' || p[4] == 'N')
+                && (p[5] == 'i' || p[5] == 'I')
+                && (p[6] == 't' || p[6] == 'T')
+                && (p[7] == 'y' || p[7] == 'Y')) {
+            *ptr = p + 8;
+            return atof(str);
+        } else {
+            *ptr = p + 3;
+            return atof(str);
+        }
+    }
+
+    if ((p[0] == 'n' || p[0] == 'N')
+            && (p[1] == 'a' || p[1] == 'A')
+            && (p[2] == 'n' || p[2] == 'N')) {
+        p += 3;
+        if (*p == '(') {
+            ++p;
+            while (*p != '\0' && *p != ')') {
+                ++p;
+            }
+
+            if (*p == ')') {
+                ++p;
+            }
+        }
+
+        *ptr = p;
+        return atof(str);
+    }
+
+    if (isdigit(*p) || *p == '.') {
+        int got_dot = 0;
+        while (isdigit(*p) || (!got_dot && *p == '.')) {
+            if (*p == '.')
+                got_dot = 1;
+            ++p;
+        }
+
+        if (*p == 'e' || *p == 'E') {
+            int i;
+            i = 1;
+            if (p[i] == '+' || p[i] == '-') {
+                ++i;
+            }
+
+            if (isdigit (p[i])) {
+                while (isdigit (p[i])) {
+                    ++i;
+                }
+
+                *ptr = p + i;
+                return atof(str);
+            }
+        }
+
+        *ptr = p;
+        return atof(str);
+    }
+
+    *ptr = (char *)str;
+    return 0.0;
+}
diff --git a/photon/libc/stdlib/strtol.c b/photon/libc/stdlib/strtol.c
new file mode 100644
index 0000000..40f5cc2
--- /dev/null
+++ b/photon/libc/stdlib/strtol.c
@@ -0,0 +1,85 @@
+#include <ctype.h>
+#include <stdint.h>
+#include <limits.h>
+
+long strtol(const char *nptr, char **endptr, int base)
+{
+    const char *s = nptr;
+    unsigned long acc;
+    int c;
+    unsigned long cutoff;
+    int neg = 0, any, cutlim;
+
+    /*
+     * 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.
+     */
+    do {
+        c = *s++;
+    } while (isspace(c));
+
+    if (c == '-') {
+        neg = 1;
+        c = *s++;
+    } else if (c == '+')
+        c = *s++;
+    if ((base == 0 || base == 16) &&
+        c == '0' && (*s == 'x' || *s == 'X')) {
+        c = s[1];
+        s += 2;
+        base = 16;
+    } else if ((base == 0 || base == 2) &&
+        c == '0' && (*s == 'b' || *s == 'B')) {
+        c = s[1];
+        s += 2;
+        base = 2;
+    }
+    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 longs is
+     * [-2147483648..2147483647] and the input base is 10,
+     * cutoff will be set to 214748364 and cutlim to either
+     * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
+     * a value > 214748364, or equal but the next digit is > 7 (or 8),
+     * the number is too big, and we will return a range error.
+     *
+     * Set any if any `digits' consumed; make it negative to indicate
+     * overflow.
+     */
+    cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
+    cutlim = cutoff % (unsigned long)base;
+    cutoff /= (unsigned long)base;
+    for (acc = 0, any = 0;; c = *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 || acc > cutoff || acc == cutoff && c > cutlim)
+            any = -1;
+        else {
+            any = 1;
+            acc *= base;
+            acc += c;
+        }
+    }
+    if (any < 0) {
+        acc = neg ? LONG_MIN : LONG_MAX;
+    } else if (neg)
+        acc = -acc;
+    if (endptr != 0)
+        *endptr = (char *)(any ? s - 1 : nptr);
+    return (acc);
+}
diff --git a/photon/libc/string/fread.c b/photon/libc/string/fread.c
new file mode 100644
index 0000000..5fe5e52
--- /dev/null
+++ b/photon/libc/string/fread.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include <__fio.h>
+
+size_t fread(void *ptr, size_t size, size_t count, FILE *fp)
+{
+    if (!size || !count) {
+        return 0;
+    }
+
+    unsigned int written = __fio_read(fp, ptr, size * count);
+    return written / size;
+}
diff --git a/photon/libc/string/fwrite.c b/photon/libc/string/fwrite.c
new file mode 100644
index 0000000..e69de29
diff --git a/photon/libc/string/strcmp.c b/photon/libc/string/strcmp.c
new file mode 100644
index 0000000..42aea66
--- /dev/null
+++ b/photon/libc/string/strcmp.c
@@ -0,0 +1,19 @@
+int strcmp(const char *s1, const char *s2)
+{
+    int i;
+    for (i = 0; s1[i] == s2[i]; i++)
+        if (s1[i] == '\0')
+            return 0;
+
+    return s1[i] - s2[i];
+}
+
+int strncmp(const char *s1, const char *s2, unsigned int n)
+{
+    for (; n > 0; s1++, s2++, --n)
+        if (*s1 != *s2)
+            return ((*(unsigned char *)s1 < *(unsigned char *)s2) ? -1 : 1);
+        else if (*s1 == '\0')
+            return 0;
+    return 0;
+}
diff --git a/photon/libc/string/strcpy.c b/photon/libc/string/strcpy.c
new file mode 100644
index 0000000..6e85814
--- /dev/null
+++ b/photon/libc/string/strcpy.c
@@ -0,0 +1,26 @@
+char *strcpy(char *output, const char *input)
+{
+    unsigned int i;
+    for (i = 0; input[i] != 0; i++) {
+        output[i] = input[i];
+    }
+
+    output[i] = '\0';
+    return output;
+}
+
+char *strncpy(char *output, const char *input, unsigned int count)
+{
+    unsigned int size = count;
+    unsigned int i;
+    for (i = 0; i < size; i++) {
+        output[i] = input[i];
+
+        if (input[i] == 0) {
+            break;
+        }
+    }
+
+    output[i] = '\0';
+    return output;
+}
diff --git a/photon/libc/string/strdup.c b/photon/libc/string/strdup.c
new file mode 100644
index 0000000..5b706ad
--- /dev/null
+++ b/photon/libc/string/strdup.c
@@ -0,0 +1,11 @@
+#include <string.h>
+#include <stdlib.h>
+
+char *strdup(const char *str)
+{
+    size_t len = strlen(str);
+    char *out = malloc(len + 1);
+    memcpy(out, str, len);
+    out[len] = 0;
+    return out;
+}
diff --git a/photon/libc/sys/magenta/__fio.h b/photon/libc/sys/magenta/__fio.h
index aa7c3b2..2c8287e 100644
--- a/photon/libc/sys/magenta/__fio.h
+++ b/photon/libc/sys/magenta/__fio.h
@@ -14,17 +14,20 @@ struct __io_file {
     unsigned long buf_idx;
     mx_handle_t handle;
     char err;
+    char unget;
 };
 
 extern int __fileno(struct __io_file *f);
 extern void __fio_init(mx_handle_t in, mx_handle_t out, mx_handle_t err);
+extern unsigned int __fio_read(struct __io_file *f, char *buf, unsigned int sz);
 extern unsigned int __fio_write(struct __io_file *f, const char *buf, unsigned int sz);
 extern unsigned int __fio_flush(struct __io_file *f);
 extern int __fio_error(struct __io_file *f);
+extern int __fio_ungetc(struct __io_file *f, char c);
 
 extern int __fio_fopen(const char *path, const char *mode, struct __io_file *out);
 extern int __fio_fclose(struct __io_file *in);
-extern int __fio_fdopen(int fd, const char *mode, struct __io_file *out);
+extern int __fio_fdopen(mx_handle_t fd, const char *mode, struct __io_file *out);
 
 #if defined(__cplusplus)
 }
diff --git a/photon/libc/sys/magenta/fio.c b/photon/libc/sys/magenta/fio.c
index f1feb6f..8c2cbc8 100644
--- a/photon/libc/sys/magenta/fio.c
+++ b/photon/libc/sys/magenta/fio.c
@@ -9,6 +9,38 @@ struct __io_file *stdin = &__stdin;
 struct __io_file *stdout = &__stdout;
 struct __io_file *stderr = &__stderr;
 
+static mx_flags_t flags_from_mode(const char *r)
+{
+    mx_flags_t out = 0;
+
+    while (*r) {
+        switch (*r) {
+        case 'r':
+            out |= MX_FILE_READ;
+            break;
+        case 'w':
+            out |= MX_FILE_WRITE;
+            break;
+        case '+':
+            out |= (MX_FILE_READ | MX_FILE_WRITE);
+            break;
+        case 'a':
+            out |= MX_FILE_APPEND;
+            break;
+        case 'b':
+            /* TODO */
+            break;
+        default:
+            out = 0;
+            return out;
+        }
+
+        r++;
+    }
+
+    return out;
+}
+
 void __fio_init(mx_handle_t in, mx_handle_t out, mx_handle_t err)
 {
     __stdin.handle = in;
@@ -16,11 +48,59 @@ void __fio_init(mx_handle_t in, mx_handle_t out, mx_handle_t err)
     __stderr.handle = err;
 }
 
+int __fio_fopen(const char *path, const char *mode, struct __io_file *fp)
+{
+    mx_handle_t h = MX_NULL_HANDLE;
+    mx_status_t stat = mx_open(MX_NULL_HANDLE, path, 0, &h);
+
+    if (stat != MX_OK) {
+        return -1;
+    }
+
+    fp->handle = h;
+    return 0;
+}
+
+int __fio_fdopen(mx_handle_t fd, const char *mode, struct __io_file *fp)
+{
+    /* TODO validate handle and mode */
+    fp->handle = fd;
+    return 0;
+}
+
 int __fileno(struct __io_file *f)
 {
     return (int)f->handle;
 }
 
+unsigned int __fio_read(struct __io_file *f, char *buf, unsigned int sz)
+{
+    if (!sz) {
+        return 0;
+    }
+
+    size_t i = 0;
+    unsigned long real_sz = 0;
+
+    if (f->unget) {
+        buf[i++] = f->unget;
+        f->unget = 0;
+        sz--;
+    }
+
+    if (!sz) {
+        return real_sz;
+    }
+
+    mx_status_t err = mx_read(f->handle, sz, buf + i, &real_sz);
+
+    if (err != MX_OK || real_sz != sz) {
+        f->err = 1;
+    }
+
+    return real_sz + i;
+}
+
 unsigned int __fio_write(struct __io_file *f, const char *buf, unsigned int sz)
 {
     for (unsigned int i = 0; i < sz; i++) {
@@ -37,6 +117,16 @@ unsigned int __fio_write(struct __io_file *f, const char *buf, unsigned int sz)
     return sz;
 }
 
+int __fio_ungetc(struct __io_file *f, char c)
+{
+    if (f->unget) {
+        return -1;
+    }
+
+    f->unget = c;
+    return 0;
+}
+
 unsigned int __fio_flush(struct __io_file *f)
 {
     unsigned long written = 0;