lab util grade 100

Makefile

@@ -188,6 +188,11 @@ UPROGS=\
 	$U/_grind\
 	$U/_wc\
 	$U/_zombie\
+	$U/_sleep\
+	$U/_pingpong\
+	$U/_primes\
+	$U/_find\
+	$U/_xargs\
 
 
 

time.txt

@@ -0,0 +1 @@
+6

user/find.c

@@ -0,0 +1,74 @@
+#include "kernel/types.h"
+#include "user/user.h"
+#include "kernel/stat.h"
+#include "kernel/fs.h"
+
+int fmtname(const char *path) {
+  int p;
+  for(p=strlen(path); p >= 0 && *(path + p) != '/'; p--);
+  p++;
+  return p;
+}
+
+void find(const char *path, const char* target) {
+    char buf[512], *p;
+    int fd;
+    struct dirent de;
+    struct stat st;
+    if((fd = open(path, 0)) < 0){
+        fprintf(2, "find: cannot open %s\n", path);
+        return;
+    }
+
+    if(fstat(fd, &st) < 0){
+        fprintf(2, "find: cannot stat %s\n", path);
+        close(fd);
+        return;
+    }
+
+    switch(st.type){
+    case T_DEVICE:
+    case T_FILE:
+        if (strcmp(path + fmtname(path), target) == 0) {
+            printf("%s\n", path);
+        }
+        break;
+
+    case T_DIR:
+        if (strcmp(path + fmtname(path), target) == 0) {
+            printf("%s\n", path);
+        }
+        if(strlen(path) + 1 + DIRSIZ + 1 > sizeof buf){
+            printf("find: path too long\n");
+            break;
+        }
+        strcpy(buf, path);
+        p = buf+strlen(buf);
+        *p++ = '/';
+        while(read(fd, &de, sizeof(de)) == sizeof(de)){
+            if(de.inum == 0)
+                continue;
+            if (strcmp(de.name, ".") == 0 || strcmp(de.name, "..") == 0)
+                continue;
+            memmove(p, de.name, DIRSIZ);
+            p[DIRSIZ] = 0;
+            if(stat(buf, &st) < 0){
+                printf("find: cannot stat %s\n", buf);
+                continue;
+            }
+            find(buf, target);
+        }
+        break;
+    }
+    close(fd);
+}
+
+int main(int argc, char** argv) {
+    if (argc != 3) {
+        printf("\x1b[31mInvalid arguments\x1b[0m\n");
+        printf("\x1b[32musage\x1b[0m: find <base directory> <file name to find>\n");
+        exit(0);
+    }
+    find(argv[1], argv[2]);
+    exit(0);
+}

user/pingpong.c

@@ -0,0 +1,27 @@
+#include "kernel/types.h"
+#include "user/user.h"
+
+int main(int argc, char** argv) {
+    int p[2]; // hell, read from p[0] and write to p[1] no matter in pa/ch
+    if (pipe(p) == -1) exit(1);
+    uint8 senddata[] = {0xAC};
+    uint8 recvdata[] = {0};
+    int pid = fork();
+    if (pid == 0) {
+        // child
+        if (read(p[0], recvdata, 1) != 1) printf("error child read\n");
+        close(p[0]);
+        printf("%d: received ping\n", getpid());
+        if (write(p[1], senddata, 1) != 1) printf("error child write\n");
+        close(p[1]);
+        exit(0);
+    }
+    else {
+        if (write(p[1], senddata, 1) != 1) printf("error parent write\n");
+        close(p[1]);
+        if (read(p[0], recvdata, 1) != 1) printf("error parent read\n");
+        printf("%d: received pong\n", getpid());
+        close(p[0]);
+        exit(0);
+    }
+}

user/primes.c

@@ -0,0 +1,51 @@
+#include "kernel/types.h"
+#include "user/user.h"
+
+void pipeline(int leftfd) {
+    int pipefd[2];
+    int p; read(leftfd, &p, sizeof(p));
+    printf("prime %d\n", p);
+    int n; 
+    int has_right = 0;
+    while (read(leftfd, &n, sizeof(n)) > 0) {
+        if (n % p != 0) {
+            if (!has_right) {
+                has_right = 1;
+                pipe(pipefd);
+                if (fork() == 0) {
+                    close(pipefd[1]);
+                    pipeline(pipefd[0]);
+                } else {
+                    close(pipefd[0]);
+                }
+            }
+            write(pipefd[1], &n, sizeof(n));
+        }
+    }
+    close(leftfd);
+    if (has_right) {
+        close(pipefd[1]);
+        while(wait(0) != -1);
+    }
+    exit(0);
+}
+
+int main(int argc, char** argv) {
+    int pipefd[2];
+    pipe(pipefd);
+    int pid = fork();
+    if (pid != 0) {
+        close(pipefd[0]); // no need to read in the feeding proc
+        for (int i = 2; i <= 35; ++ i) {
+            write(pipefd[1], &i, sizeof(i));
+        }
+        close(pipefd[1]);
+        while(wait(0) != -1);
+        exit(0);
+    }
+    else {
+        close(pipefd[1]);  // pipeline proc will have its own write pipe
+        pipeline(pipefd[0]);
+    }
+    exit(0);
+}

user/sleep.c

@@ -0,0 +1,17 @@
+#include "kernel/types.h"
+#include "user/user.h"
+
+int main(int argc, char** argv) {
+    if (argc != 2) {
+        printf("\x1b[31mUnexpected argument\x1b[0m\n");
+        printf("usage: sleep <ticks>\n");
+        exit(0);
+    }
+    int ticks = atoi(argv[1]);
+    int ret = sleep(ticks);
+    if (ret) {
+        printf("\x1b[31mFailed to sleep\x1b[0m\n");
+        exit(-1);
+    }
+    exit(0);
+}

user/xargs.c

@@ -0,0 +1,59 @@
+#include "kernel/param.h"
+#include "kernel/types.h"
+#include "user/user.h"
+
+static inline int is_ws(const char ch) {
+    return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r';
+}
+
+int main(int argc, char** argv) {
+    int STDIN = 0;
+    char linebuf[1024];
+    char* p = linebuf;
+    char* _argv[MAXARG];
+    while (read(STDIN, p, 1) > 0) {
+        if (*p == '\n') {
+            int i;
+            int in_ws = 1;
+            for (i = 0; i < argc - 1; ++i) {
+                _argv[i] = argv[i + 1];
+            }
+            for (char* p0 = linebuf; p0 <= p; ++p0) {
+                if (is_ws(*p0)) {
+                    if (!in_ws) {
+                        in_ws = 1;
+                        i++;
+                    }
+                    *p0 = '\0';
+                } else if (in_ws) {
+                    in_ws = 0;
+                    _argv[i] = p0;
+                }
+                if (i >= MAXARG) {
+                    printf("warning: too many arguments");
+                    break;
+                }
+            }
+            *p = '\0';
+            _argv[i] = 0;
+            // for (int j = 0; j < i; ++ j) {
+            //     printf("%s\n", _argv[j]);
+            // }
+            if (fork() == 0) {
+                exec(_argv[0], _argv);
+                exit(0);
+            } else {
+                p = linebuf;
+                while (wait(0) != -1)
+                    ;
+            }
+        } else {
+            p++;
+            if (p >= linebuf + sizeof(linebuf)) {
+                printf("line buffer exceeded\n");
+                exit(0);
+            }
+        }
+    }
+    exit(0);
+}