Use standard declarations of string functions

Now they agree between kernel, user, and Linux. (This was motivated by link errors in mtrace caused by disagreements between xv6 kernel and user code, but also seems like the right thing to do.)

Use standard declarations of string functions
3ab59330 · Austin Clements · 6266bd9a · 3ab59330 · 3ab59330 · 3ab59330
--- a/include/kernel.hh
+++ b/include/kernel.hh
@@ -215,14 +215,14 @@ int             kmemcpy(void*, void*, u64);
 u64             syscall(u64 a0, u64 a1, u64 a2, u64 a3, u64 a4, u64 num);
 // string.c
-extern  "C" int  memcmp(const void*, const void*, u32);
+extern  "C" int  memcmp(const void*, const void*, size_t);
-void*           memmove(void*, const void*, u32);
+void*           memmove(void*, const void*, size_t);
-extern "C" void* memset(void*, int, u32);
+extern "C" void* memset(void*, int, size_t);
-extern "C" void* memcpy(void*, const void *, u32);
+extern "C" void* memcpy(void*, const void *, size_t);
-char*           safestrcpy(char*, const char*, u32);
+char*           safestrcpy(char*, const char*, size_t);
 extern "C" unsigned int strlen(const char*);
-int             strncmp(const char*, const char*, u32);
+int             strncmp(const char*, const char*, size_t);
-char*           strncpy(char*, const char*, u32);
+char*           strncpy(char*, const char*, size_t);
 int             strcmp(const char *p, const char *q);
 // swtch.S

--- a/include/mtrace.h
+++ b/include/mtrace.h
@@ -11,8 +11,8 @@ typedef unsigned long long uint64_t;
 typedef __PTRDIFF_TYPE__ intptr_t;
 typedef unsigned __PTRDIFF_TYPE__ uintptr_t;
-void* memcpy(void *dst, const void *src, u32 n);
+void* memcpy(void *dst, const void *src, size_t n);
-char* strncpy(char *s, const char *t, int n);
+char* strncpy(char *s, const char *t, size_t n);
 #define RET_IP() ((unsigned long)__builtin_return_address(0))

--- a/include/user.h
+++ b/include/user.h
@@ -36,10 +36,10 @@ int setfs(u64 base);
 int stat(char*, struct stat*);
 int fstatat(int dirfd, const char*, struct stat*);
 char* strcpy(char*, const char*);
-void *memmove(void*, const void*, int);
+void* memmove(void*, const void*, size_t);
 char* strchr(const char*, char c);
 int strcmp(const char*, const char*);
-int strncmp(const char *p, const char *q, u32 n);
+int strncmp(const char *p, const char *q, size_t n);
 int open(const char*, int);
 char* gets(char*, int max);

--- a/kernel/string.cc
+++ b/kernel/string.cc
@@ -3,14 +3,14 @@
 #include "kernel.hh"
 void*
-memset(void *dst, int c, u32 n)
+memset(void *dst, int c, size_t n)
 {
  stosb(dst, c, n);
  return dst;
 }
 int
-memcmp(const void *v1, const void *v2, u32 n)
+memcmp(const void *v1, const void *v2, size_t n)
 {
  const u8 *s1, *s2;
@@ -26,7 +26,7 @@ memcmp(const void *v1, const void *v2, u32 n)
 }
 void*
-memmove(void *dst, const void *src, u32 n)
+memmove(void *dst, const void *src, size_t n)
 {
  const char *s;
  char *d;
@@ -47,13 +47,13 @@ memmove(void *dst, const void *src, u32 n)
 // memcpy exists to placate GCC.  Use memmove.
 void*
-memcpy(void *dst, const void *src, u32 n)
+memcpy(void *dst, const void *src, size_t n)
 {
  return memmove(dst, src, n);
 }
 int
-strncmp(const char *p, const char *q, u32 n)
+strncmp(const char *p, const char *q, size_t n)
 {
  while(n > 0 && *p && *p == *q)
    n--, p++, q++;
@@ -63,7 +63,7 @@ strncmp(const char *p, const char *q, u32 n)
 }
 char*
-strncpy(char *s, const char *t, u32 n)
+strncpy(char *s, const char *t, size_t n)
 {
  char *os;
@@ -77,7 +77,7 @@ strncpy(char *s, const char *t, u32 n)
 // Like strncpy but guaranteed to NUL-terminate.
 char*
-safestrcpy(char *s, const char *t, u32 n)
+safestrcpy(char *s, const char *t, size_t n)
 {
  char *os;

--- a/lib/ulib.c
+++ b/lib/ulib.c
@@ -5,7 +5,7 @@
 #include "amd64.h"
 char*
-strncpy(char *s, const char *t, int n)
+strncpy(char *s, const char *t, size_t n)
 {
  int tlen = strlen((char *)t);
  memmove(s, (char *)t, n > tlen ? tlen : n);
@@ -34,7 +34,7 @@ strcmp(const char *p, const char *q)
 }
 int
-strncmp(const char *p, const char *q, u32 n)
+strncmp(const char *p, const char *q, size_t n)
 {
  while(n > 0 && *p && *p == *q)
    n--, p++, q++;
@@ -127,13 +127,13 @@ atoi(const char *s)
 }
 void*
-memcpy(void *dst, const void *src, unsigned int n)
+memcpy(void *dst, const void *src, size_t n)
 {
  return memmove(dst, (void *)src, n);
 }
 void*
-memmove(void *vdst, const void *vsrc, int n)
+memmove(void *vdst, const void *vsrc, size_t n)
 {
  const char *src;
  char *dst;