CS 3733 Operating Systems, Fall 2003 Assignment 1 Comments

• perror prints an error message based on the value of errno.
  You cannot use it if errno is not set.
  Do not use it when getinfo returns -1.
• The getinfo function should not write anything to startard output or standard error. Error message should be printed by the calling program.
• It is not necessary to allocate an extra array in getinfo
• If getinfo calls malloc (it should not have to) then it must free any memory it allocates.
• Whenever you do a malloc you must check for errors.
• sizeof(int) is not the number of bytes in a string that is used to print an integer.
• time(...) returns the current time. It cannot be used in this assignment.
• You must remove all lint warnings of the form:
  implicitly declared to return int
  function argument ( number ) used inconsistently
• One of the things you were supposed to do in this assignment was to read the man page for snprintf. You should specifically look at the section on RETURN VALUES.
• Below is a simple implementation of getinfo
  Note that you do not need an extra array and most of the work is done by snprintf.

  #include <stdio.h>
  #include <string.h>
  #include <time.h>
  #include <sys/stat.h>
  
  int getinfo(char *path, char *buf, int bufsize) {
     int i;
     struct stat statbuf;
     int needed;
  
     if (stat(path, &statbuf) == -1)
        return -1;
     needed = snprintf(buf,bufsize,"%s %lld %lld\n",path,
                     (long long)statbuf.st_mtime, (long long)statbuf.st_size);
     if (needed >= bufsize)
        return -1;
     for (i=0;i<strlen(path);i++)
        if (buf[i] == ' ')
           buf[i] = '%';
     return 0;
  }