1 files changed, 122 insertions, 0 deletions
diff --git a/pgm3/accessed.c b/pgm3/accessed.c
new file mode 100644
index 0000000..b1007a9
--- /dev/null
+++ b/pgm3/accessed.c
@@ -0,0 +1,122 @@
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <time.h>
+#include <unistd.h>
+
+#define FALSE 0
+#define FILE_BUFF 4096
+#define TRUE  1
+
+struct NODE {
+    char filename[FILE_BUFF];
+    int inode;
+    long atime;
+    struct NODE *next;
+};
+
+int makeList(struct NODE **head) {
+    /*
+     * makeList builds a linked list of nodes representing the filenames
+     * given on stdin and their access time.
+     */
+    char filename[FILE_BUFF];
+    int inList = FALSE;
+    struct NODE *currentNode = NULL;
+    struct NODE *newNode = NULL;
+    struct stat statData;
+
+    while (scanf(" %s", filename) == 1) {
+
+        if (stat(filename, &statData) == 0 && S_ISREG(statData.st_mode)) {
+            inList = FALSE;
+
+            for (currentNode = *head; currentNode != NULL; currentNode = currentNode->next) {
+
+                if (currentNode->inode == statData.st_ino) {
+                    inList = TRUE;
+                }
+
+            }
+
+            if (!inList) {
+                newNode = (struct NODE *) malloc(sizeof(struct NODE));
+                newNode->inode = statData.st_ino;
+                strcpy(newNode->filename, filename);
+                newNode->atime = (time(NULL) - statData.st_atime) / 86400;
+                newNode->next = *head;
+                *head = newNode;
+            }
+
+        }
+
+    }
+
+    return 0;
+}
+
+int main(int argc, char *argv[]) {
+    /*
+     * accessed takes in filenames from stdin and one command line argument,
+     * "num". It then builds a linked list of the unique, regular files and
+     * prints out those files not accessed in "num" days (if num is positive)
+     * or prints out those files accesssed within "num" days (if num is
+     * negative).
+     */
+    int accessedNum = 0;
+    struct NODE *currentNode = NULL;
+    struct NODE *list = NULL;
+
+    // Go through args
+    if (argc != 2) {
+        fprintf(stderr, "accessed: usage: ./accessed [num days]\n");
+        exit(1);
+    }
+
+    accessedNum = strtol(argv[1], NULL, 10);
+
+    if (errno == EINVAL) {
+        fprintf(stderr, "accessed: error: num must be integer type.\n");
+        exit(1);
+    }
+    else if (errno == ERANGE) {
+        fprintf(stderr, "accessed: error: num must be of integer size.\n");
+        exit(1);
+    }
+    else if (accessedNum == 0) {
+        fprintf(stderr, "accessed: error: num must be nonzero integer.\n");
+        exit(1);
+    }
+
+    if (makeList(&list) != 0) {
+        fprintf(stderr, "accessed: error: could not build linked list.\n");
+        exit(1);
+    }
+
+    // print out filenames that match requested access time
+    for (currentNode = list; currentNode != NULL; currentNode = currentNode->next) {
+
+        if (accessedNum > 0 && currentNode->atime > accessedNum) { // not within num days
+            printf("%s\n", currentNode->filename);
+        }
+
+        if (accessedNum < 0 && currentNode->atime <= (accessedNum * -1)) { // within num days
+            printf("%s\n", currentNode->filename);
+        }
+
+    }
+
+    // free list
+    while (currentNode != NULL) {
+        currentNode = list;
+        list = list->next;
+        free(currentNode);
+    }
+
+    exit(0);
+}