my solution to lab5

lab/user/ls.c

@@ -0,0 +1,91 @@
+#include <inc/lib.h>
+
+int flag[256];
+
+void lsdir(const char*, const char*);
+void ls1(const char*, bool, off_t, const char*);
+
+void
+ls(const char *path, const char *prefix)
+{
+	int r;
+	struct Stat st;
+
+	if ((r = stat(path, &st)) < 0)
+		panic("stat %s: %e", path, r);
+	if (st.st_isdir && !flag['d'])
+		lsdir(path, prefix);
+	else
+		ls1(0, st.st_isdir, st.st_size, path);
+}
+
+void
+lsdir(const char *path, const char *prefix)
+{
+	int fd, n;
+	struct File f;
+
+	if ((fd = open(path, O_RDONLY)) < 0)
+		panic("open %s: %e", path, fd);
+	while ((n = readn(fd, &f, sizeof f)) == sizeof f)
+		if (f.f_name[0])
+			ls1(prefix, f.f_type==FTYPE_DIR, f.f_size, f.f_name);
+	if (n > 0)
+		panic("short read in directory %s", path);
+	if (n < 0)
+		panic("error reading directory %s: %e", path, n);
+}
+
+void
+ls1(const char *prefix, bool isdir, off_t size, const char *name)
+{
+	const char *sep;
+
+	if(flag['l'])
+		printf("%11d %c ", size, isdir ? 'd' : '-');
+	if(prefix) {
+		if (prefix[0] && prefix[strlen(prefix)-1] != '/')
+			sep = "/";
+		else
+			sep = "";
+		printf("%s%s", prefix, sep);
+	}
+	printf("%s", name);
+	if(flag['F'] && isdir)
+		printf("/");
+	printf("\n");
+}
+
+void
+usage(void)
+{
+	printf("usage: ls [-dFl] [file...]\n");
+	exit();
+}
+
+void
+umain(int argc, char **argv)
+{
+	int i;
+	struct Argstate args;
+
+	argstart(&argc, argv, &args);
+	while ((i = argnext(&args)) >= 0)
+		switch (i) {
+		case 'd':
+		case 'F':
+		case 'l':
+			flag[i]++;
+			break;
+		default:
+			usage();
+		}
+
+	if (argc == 1)
+		ls("/", "");
+	else {
+		for (i = 1; i < argc; i++)
+			ls(argv[i], argv[i]);
+	}
+}
+