Merge pull request #13 from seekbytes/uptime

Added uptime command

programs/CMakeLists.txt

@@ -68,6 +68,7 @@ set(PROGRAMS
     sleep.c
     man.c
     edit.c
+    uptime.c
 )
 foreach(PROGRAM ${PROGRAMS})
     # Prepare the program name.

programs/uptime.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/unistd.h>
+#include <sys/stat.h>
+
+int main(){
+  int uptime_fd = open("/proc/uptime", O_RDONLY, 0600);
+  if(uptime_fd == -1){
+    printf("Impossible to retrieve /proc/uptime file");
+    return -1;
+  }
+  
+  // Read the content of /proc/uptime
+  
+  char buffer[64];
+  if(read(uptime_fd, buffer, sizeof(char)*64) == -1){
+    printf("Impossible to read /proc/uptime content");
+    return -1;
+  }
+  
+  int uptime = atoi(buffer);
+  
+  // Transform uptime into hours, days, mins, and seconds
+  
+  int updays = uptime / 86400;
+  int uphours = (uptime - (updays * 86400)) / 3600;
+  int upmins = (uptime - (updays * 86400) - (uphours * 3600)) / 60;
+  int upseconds = (uptime - (updays * 86400) - (uphours * 3600) - (upmins * 60));
+  
+  printf("Days: %d Hours: %d Minutes: %d Seconds: %d \n", updays, uphours, upmins, upseconds);
+  close(uptime_fd);
+  return 0;
+}