Initial commit.

programming-assignment.c

@@ -0,0 +1,124 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+
+/**************************************************************************
+ * Authors: Gary Fleming, Amber McCloughan
+ * Class: CIS452 - Operating Systems Concepts
+ * Professor: Dr. Greg Wolffe
+ * Date: 4/19/2019
+ *
+ * Program that mimics the ln command's basic functionality.
+ * You can create soft links or hard links using this program.
+ *
+ * Arguments
+ * -------------------------------------------------------------------------
+ * -s               :   Specifies we're creating a soft link.
+ * [source]         :   Input a file that will be linked to. MUST COME
+ *                      FIRST!
+ * [destination]    :   Input a file name for the new link file. MUST
+ *                      COME LAST!
+ ***************************************************************************/
+
+#define MAX_BUF_SIZE 102
+
+/**
+ * Main function of the program. Takes in
+ * three possible arguments: -s, [source],
+ * and [destination].
+ *
+ * @param argc, number of arguments.
+ * @param argv, the actual arguments.
+ */
+int main(int argc, char *argv[])
+{
+    // Tracking if we're doing a symlink.
+    int sFlag = 0;
+
+    // For counting arguments.
+    int numCount = 0;
+
+    // Used in the for loop when checking arguments.
+    int i;
+
+    // Buffer for link source.
+    char *source = malloc(MAX_BUF_SIZE * sizeof(char));
+
+    // Buffer for the new link.
+    char *dest = malloc(MAX_BUF_SIZE * sizeof(char));
+
+    // Reading the program arguments.
+    for (i = 1; i < argc; i++)
+    {
+        // If we found the -s flag.
+        if (!strcmp(argv[i], "-s"))
+        {
+            sFlag = 1;
+        }
+        // For file path arguments.
+        else
+        {
+            // For the source file.
+            if (numCount == 0)
+            {
+                strcpy(source, argv[i]);
+                numCount++;
+            }
+            // For the destination file (link).
+            else if (numCount == 1)
+            {
+                strcpy(dest, argv[i]);
+                numCount++;
+            }
+            // There must have been too many arguments.
+            else
+            {
+                printf("Too many arguments provided!\n");
+                free(source);
+                free(dest);
+                return -1;
+            }
+        }
+    }
+
+    // There must have not been enough arguments.
+    if (numCount < 2)
+    {
+        printf("Not enough arguments provided!\n");
+        free(source);
+        free(dest);
+        return -1;
+    }
+
+    // If we're dealing with a hard link.
+    if (sFlag == 0)
+    {
+        if (link(source, dest) < 0)
+        {
+            perror("Huh?  There is... ");
+            free(source);
+            free(dest);
+            return -1;
+        }
+    }
+    // Otherwise, we're dealing with a soft link.
+    else
+    {
+        if (symlink(source, dest) < 0)
+        {
+            perror("Huh?  There is... ");
+            free(source);
+            free(dest);
+            return -1;
+        }
+    }
+
+    // Freeing resources.
+    free(source);
+    free(dest);
+
+    // Goodbye (for the semester)!
+    return 0;
+}