pingpong finished

user/pingpong.c

@@ -0,0 +1,21 @@
+#include "kernel/types.h"
+#include "user/user.h"
+
+int main(int argc, char *argv[]) {
+  int proc_f2s[2], proc_s2f[2];
+  char buffer[8];
+  pipe(proc_f2s);
+  pipe(proc_s2f);
+
+  if (fork() == 0) {
+    read(proc_s2f[0], buffer, 4);
+    printf("%d: received %s\n", getpid(), buffer);
+    write(proc_f2s[1], "pong", strlen("pong"));
+  } else {
+    write(proc_s2f[1], "ping", strlen("ping"));
+    read(proc_f2s[0], buffer, 4);
+    printf("%d: received %s\n", getpid(), buffer);
+  }
+
+  exit(0);
+}

user/ulib.c

@@ -1,134 +1,112 @@
-#include "kernel/types.h"
-#include "kernel/stat.h"
 #include "kernel/fcntl.h"
+#include "kernel/stat.h"
+#include "kernel/types.h"
 #include "user/user.h"
 
 //
 // wrapper so that it's OK if main() does not call exit().
 //
-void
-_main()
-{
+void _main() {
   extern int main();
   main();
   exit(0);
 }
 
-char*
-strcpy(char *s, const char *t)
-{
+char *strcpy(char *s, const char *t) {
   char *os;
 
   os = s;
-  while((*s++ = *t++) != 0)
+  while ((*s++ = *t++) != 0)
     ;
   return os;
 }
 
-int
-strcmp(const char *p, const char *q)
-{
-  while(*p && *p == *q)
+int strcmp(const char *p, const char *q) {
+  while (*p && *p == *q)
     p++, q++;
   return (uchar)*p - (uchar)*q;
 }
 
-uint
-strlen(const char *s)
-{
+uint strlen(const char *s) {
   int n;
 
-  for(n = 0; s[n]; n++)
+  for (n = 0; s[n]; n++)
     ;
   return n;
 }
 
-void*
-memset(void *dst, int c, uint n)
-{
-  char *cdst = (char *) dst;
+void *memset(void *dst, int c, uint n) {
+  char *cdst = (char *)dst;
   int i;
-  for(i = 0; i < n; i++){
+  for (i = 0; i < n; i++) {
     cdst[i] = c;
   }
   return dst;
 }
 
-char*
-strchr(const char *s, char c)
-{
-  for(; *s; s++)
-    if(*s == c)
-      return (char*)s;
+char *strchr(const char *s, char c) {
+  for (; *s; s++)
+    if (*s == c)
+      return (char *)s;
   return 0;
 }
 
-char*
-gets(char *buf, int max)
-{
+char *gets(char *buf, int max) {
   int i, cc;
   char c;
 
-  for(i=0; i+1 < max; ){
+  for (i = 0; i + 1 < max;) {
     cc = read(0, &c, 1);
-    if(cc < 1)
+    if (cc < 1)
       break;
     buf[i++] = c;
-    if(c == '\n' || c == '\r')
+    if (c == '\n' || c == '\r')
       break;
   }
   buf[i] = '\0';
   return buf;
 }
 
-int
-stat(const char *n, struct stat *st)
-{
+int stat(const char *n, struct stat *st) {
   int fd;
   int r;
 
   fd = open(n, O_RDONLY);
-  if(fd < 0)
+  if (fd < 0)
     return -1;
   r = fstat(fd, st);
   close(fd);
   return r;
 }
 
-int
-atoi(const char *s)
-{
+int atoi(const char *s) {
   int n;
 
   n = 0;
-  while('0' <= *s && *s <= '9')
-    n = n*10 + *s++ - '0';
+  while ('0' <= *s && *s <= '9')
+    n = n * 10 + *s++ - '0';
   return n;
 }
 
-void*
-memmove(void *vdst, const void *vsrc, int n)
-{
+void *memmove(void *vdst, const void *vsrc, int n) {
   char *dst;
   const char *src;
 
   dst = vdst;
   src = vsrc;
   if (src > dst) {
-    while(n-- > 0)
+    while (n-- > 0)
       *dst++ = *src++;
   } else {
     dst += n;
     src += n;
-    while(n-- > 0)
+    while (n-- > 0)
       *--dst = *--src;
   }
   return vdst;
 }
 
-int
-memcmp(const void *s1, const void *s2, uint n)
-{
+int memcmp(const void *s1, const void *s2, uint n) {
   const char *p1 = s1, *p2 = s2;
   while (n-- > 0) {
     if (*p1 != *p2) {
@@ -140,8 +118,6 @@ memcmp(const void *s1, const void *s2, uint n)
   return 0;
 }
 
-void *
-memcpy(void *dst, const void *src, uint n)
-{
+void *memcpy(void *dst, const void *src, uint n) {
   return memmove(dst, src, n);
 }

user/user.h

@@ -1,41 +1,42 @@
+#include "kernel/types.h"
 struct stat;
 
 // system calls
 int fork(void);
 int exit(int) __attribute__((noreturn));
-int wait(int*);
-int pipe(int*);
-int write(int, const void*, int);
-int read(int, void*, int);
+int wait(int *);
+int pipe(int *);
+int write(int, const void *, int);
+int read(int, void *, int);
 int close(int);
 int kill(int);
-int exec(const char*, char**);
-int open(const char*, int);
-int mknod(const char*, short, short);
-int unlink(const char*);
-int fstat(int fd, struct stat*);
-int link(const char*, const char*);
-int mkdir(const char*);
-int chdir(const char*);
+int exec(const char *, char **);
+int open(const char *, int);
+int mknod(const char *, short, short);
+int unlink(const char *);
+int fstat(int fd, struct stat *);
+int link(const char *, const char *);
+int mkdir(const char *);
+int chdir(const char *);
 int dup(int);
 int getpid(void);
-char* sbrk(int);
+char *sbrk(int);
 int sleep(int);
 int uptime(void);
 
 // ulib.c
-int stat(const char*, struct stat*);
-char* strcpy(char*, const char*);
-void *memmove(void*, const void*, int);
-char* strchr(const char*, char c);
-int strcmp(const char*, const char*);
-void fprintf(int, const char*, ...);
-void printf(const char*, ...);
-char* gets(char*, int max);
-uint strlen(const char*);
-void* memset(void*, int, uint);
-void* malloc(uint);
-void free(void*);
-int atoi(const char*);
+int stat(const char *, struct stat *);
+char *strcpy(char *, const char *);
+void *memmove(void *, const void *, int);
+char *strchr(const char *, char c);
+int strcmp(const char *, const char *);
+void fprintf(int, const char *, ...);
+void printf(const char *, ...);
+char *gets(char *, int max);
+uint strlen(const char *);
+void *memset(void *, int, uint);
+void *malloc(uint);
+void free(void *);
+int atoi(const char *);
 int memcmp(const void *, const void *, uint);
 void *memcpy(void *, const void *, uint);