apps: Add a 'stat' utility

apps/Makefile

@@ -1,4 +1,4 @@
-APPS := init sym sh crash uname uptime hello ps ls args cat
+APPS := init sym sh crash uname uptime hello ps ls args cat stat
 
 APPS_DIR := $(LUNA_ROOT)/apps
 APPS_SRC := $(APPS_DIR)/src

apps/src/stat.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+
+const char* mode_to_string(mode_t mode)
+{
+    static char mode_string[12];
+
+    char mode_set[12] = {'s', 'g', 'r', 'w', 'x', 'r', 'w', 'x', 'r', 'w', 'x', 0};
+    mode_t mode_val[12] = {S_ISUID, S_ISGID, S_IRUSR, S_IWUSR, S_IXUSR, S_IRGRP,
+                           S_IWGRP, S_IXGRP, S_IROTH, S_IWOTH, S_IXOTH, S_IFMT};
+
+    for (int i = 0; i < 12; i++)
+    {
+        if (mode & mode_val[i]) mode_string[i] = mode_set[i];
+        else
+            mode_string[i] = '-';
+    }
+
+    return mode_string;
+}
+
+int main(int argc, char** argv)
+{
+    if (argc == 1)
+    {
+        fprintf(stderr, "Usage: stat [file]\n");
+        return EXIT_FAILURE;
+    }
+
+    struct stat st;
+    if (stat(argv[1], &st) < 0)
+    {
+        perror("stat");
+        return EXIT_FAILURE;
+    }
+
+    printf("Type: ");
+
+    switch (st.st_mode & S_IFMT)
+    {
+    case S_IFREG: puts("Regular file"); break;
+    case S_IFDIR: puts("Directory"); break;
+    case S_IFCHR: puts("Character device"); break;
+    default: puts("Unknown"); break;
+    }
+
+    printf("Length: %ld\n", st.st_size);
+    printf("Inode: %ld\n", st.st_ino);
+    printf("UID: %d\n", st.st_uid);
+    printf("GID: %d\n", st.st_gid);
+    printf("Mode: %s\n", mode_to_string(st.st_mode));
+
+    return EXIT_SUCCESS;
+}