apps: Add ps (uses pstat)

apps/Makefile

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

apps/src/block.c

@@ -1,34 +0,0 @@
-#include <fcntl.h>
-#include <stdio.h>
-#include <unistd.h>
-
-int main()
-{
-    int fd = open("/dev/kbd", O_RDONLY | O_NONBLOCK);
-    if (fd < 0)
-    {
-        perror("open");
-        return 1;
-    }
-
-    FILE* fp = fdopen(fd, "r");
-    if (!fp)
-    {
-        perror("fdopen");
-        close(fd);
-        return 1;
-    }
-
-    char buf[32];
-    fread(buf, sizeof(buf) - 1, 1, fp);
-    if (ferror(fp))
-    {
-        perror("fread");
-        fclose(fp);
-        return 1;
-    }
-
-    fclose(fp);
-
-    return 0;
-}

apps/src/ps.c

@@ -0,0 +1,44 @@
+#include <errno.h>
+#include <luna/pstat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+pid_t get_current_max_threads()
+{
+    pid_t result = pstat(-1, NULL);
+    if (result < 0)
+    {
+        perror("pstat(-1)");
+        exit(1);
+    }
+    return result;
+}
+
+void display_process(struct pstat* pstatbuf)
+{
+    printf("%ld %ld %s %s (%ld ms)\n", pstatbuf->pt_pid, pstatbuf->pt_ppid, pstatbuf->pt_name, pstname(pstatbuf),
+           pstatbuf->pt_time);
+}
+
+int try_pstat(pid_t pid, struct pstat* pstatbuf)
+{
+    pid_t result = pstat(pid, pstatbuf);
+    if (result < 0)
+    {
+        if (errno == ESRCH) return 0;
+        perror("pstat");
+        exit(1);
+    }
+    return 1;
+}
+
+int main()
+{
+    struct pstat pst;
+    pid_t max = get_current_max_threads();
+    for (pid_t pid = 0; pid <= max; pid++)
+    {
+        if (try_pstat(pid, &pst)) { display_process(&pst); }
+    }
+}