dev(shell): implement basic shell tools

fixed(file-system): fixed read and write bugs

1 files changed, 48 insertions, 0 deletions

diff --git a/src/user/cat.cc b/src/user/cat.cc
new file mode 100644
index 0000000..67feb1c
--- /dev/null
+++ b/src/user/cat.cc
@@ -0,0 +1,48 @@
+#include "ulib/stdio.h"
+#include "ulib/stdlib.h"
+#include "ulib/string.h"
+#include "user/user.h"
+#include "common/fcntl.h"
+
+char buf[512];
+
+void cat(int fd)
+{
+    int n;
+    while ((n = read(fd, buf, sizeof(buf))) > 0)
+    {
+        if (write(1, buf, n) != n)
+        {
+            printf("cat: write error\n");
+            exit(1);
+        }
+    }
+    if (n < 0)
+    {
+        printf("cat: read error\n");
+        exit(1);
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    int fd, i;
+
+    if (argc <= 1)
+    {
+        cat(0);
+        exit(0);
+    }
+
+    for (i = 1; i < argc; i++)
+    {
+        if ((fd = open(argv[i], O_RDONLY)) < 0)
+        {
+            printf("cat: cannot open %s\n", argv[i]);
+            exit(1);
+        }
+        cat(fd);
+        close(fd);
+    }
+    exit(0);
+}
\ No newline at end of file