1 files changed, 108 insertions, 0 deletions
diff --git a/user/bin/ls.c b/user/bin/ls.c
new file mode 100644
index 0000000..e04b39f
--- /dev/null
+++ b/user/bin/ls.c
@@ -0,0 +1,108 @@
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <errno.h>
+
+static int do_ls(const char *dir)
+{
+    int fd;
+    struct dirent *dirent;
+    int nbytes;
+    char tmpbuf[256];
+    stat_t sbuf;
+
+    union {
+        struct dirent dirent;
+        char buf[4096];
+    } lsb;
+
+    fd = open(dir, O_RDONLY, 0600);
+    if (fd < 0)
+    {
+        fprintf(stderr, "ls: unable to open \"%s\": errno %d\n", dir, errno);
+        return 1;
+    }
+
+    while ((nbytes = getdents(fd, &lsb.dirent, sizeof(lsb))) > 0)
+    {
+        dirent = &lsb.dirent;
+
+        if (nbytes % sizeof(struct dirent))
+        {
+            fprintf(stderr,
+                    "ls: incorrect return value from getdents (%d):"
+                    " not a multiple of sizeof(struct dirent) (%ld)\n",
+                    nbytes, sizeof(struct dirent));
+            return 1;
+        }
+        do
+        {
+            int reclen;
+            int size;
+
+            snprintf(tmpbuf, sizeof(tmpbuf), "%s/%s", dir, dirent->d_name);
+            if (0 == stat(tmpbuf, &sbuf))
+            {
+                size = sbuf.st_size;
+            }
+            else
+            {
+                size = 0;
+            }
+
+            reclen = sizeof(struct dirent);
+            fprintf(stdout, "%7d  %-20s   %d\n", size, dirent->d_name,
+                    dirent->d_ino);
+            dirent = (struct dirent *)(((char *)dirent) + reclen);
+            nbytes -= reclen;
+        } while (nbytes);
+    }
+    if (nbytes < 0)
+    {
+        if (errno == ENOTDIR)
+        {
+            fprintf(stdout, "%s\n", dir);
+        }
+        else
+        {
+            fprintf(stderr, "ls: couldn't list %s: errno %d\n", dir, errno);
+        }
+    }
+
+    if (close(fd) < 0)
+    {
+        fprintf(stderr, "ls: close %s: errno %d\n", dir, errno);
+    }
+    return 0;
+}
+
+int main(int argc, char **argv)
+{
+    int ret;
+
+    if (argc < 2)
+    {
+        ret = do_ls(".");
+    }
+    else if (argc < 3)
+    {
+        ret = do_ls(argv[1]);
+    }
+    else
+    {
+        int error;
+        int argn;
+
+        error = 0;
+        for (argn = 1; argn < argc; argn++)
+        {
+            fprintf(stdout, "%s:\n", argv[argn]);
+            error += do_ls(argv[argn]);
+            fprintf(stdout, "\n");
+        }
+        ret = error;
+    }
+    return ret;
+}