find command

Makefile

@@ -116,6 +116,7 @@ mkfs/mkfs: mkfs/mkfs.c $K/fs.h $K/param.h
 .PRECIOUS: %.o
 
 UPROGS=\
+	$U/_find\
 	$U/_cat\
 	$U/_echo\
 	$U/_forktest\
@@ -133,8 +134,8 @@ UPROGS=\
 	$U/_wc\
 	$U/_zombie\
 
-fs.img: mkfs/mkfs README.md $(UPROGS)
-	mkfs/mkfs fs.img README.md $(UPROGS)
+fs.img: mkfs/mkfs README.md $(UPROGS) tester.txt
+	mkfs/mkfs fs.img README.md $(UPROGS) tester.txt
 
 -include kernel/*.d user/*.d
 

tester.txt

@@ -0,0 +1,17 @@
+  ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⣤⡤⠤⠤⠤⣤⣄⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⡤⠞⠋⠁⠀⠀⠀⠀⠀⠀⠀⠉⠛⢦⣤⠶⠦⣤⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⠀⢀⣴⠞⢋⡽⠋⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠃⠀⠀⠙⢶⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⣰⠟⠁⠀⠘⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢰⡀⠀⠀⠉⠓⠦⣤⣤⣤⣤⣤⣤⣄⣀⠀⠀⠀
+⠀⠀⠀⠀⣠⠞⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣴⣷⡄⠀⠀⢻⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠻⣆⠀
+⠀⠀⣠⠞⠁⠀⠀⣀⣠⣏⡀⠀⢠⣶⣄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠹⠿⡃⠀⠀⠀⣧⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠸⡆
+⢀⡞⠁⠀⣠⠶⠛⠉⠉⠉⠙⢦⡸⣿⡿⠀⠀⠀⡄⢀⣀⣀⡶⠀⠀⠀⢀⡄⣀⠀⣢⠟⢦⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣸⠃
+⡞⠀⠀⠸⠁⠀⠀⠀⠀⠀⠀⢳⢀⣠⠀⠀⠀⠉⠉⠀⠀⣀⠀⠀⠀⢀⣠⡴⠞⠁⠀⠀⠈⠓⠦⣄⣀⠀⠀⠀⠀⣀⣤⠞⠁⠀
+⣧⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⠀⠁⠀⢀⣀⣀⡴⠋⢻⡉⠙⠾⡟⢿⣅⠀⠀⠀⠀⠀⠀⠀⠀⠀⠉⠉⠙⠛⠉⠉⠀⠀⠀⠀
+⠘⣦⡀⠀⠀⠀⠀⠀⠀⣀⣤⠞⢉⣹⣯⣍⣿⠉⠟⠀⠀⣸⠳⣄⡀⠀⠀⠙⢧⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠈⠙⠒⠒⠒⠒⠚⠋⠁⠀⡴⠋⢀⡀⢠⡇⠀⠀⠀⠀⠃⠀⠀⠀⠀⠀⢀⡾⠋⢻⡄⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⡇⠀⢸⡀⠸⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⠀⠀⢠⡇⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣇⠀⠀⠉⠋⠻⣄⠀⠀⠀⠀⠀⣀⣠⣴⠞⠋⠳⠶⠞⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠳⠦⢤⠤⠶⠋⠙⠳⣆⣀⣈⡿⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠉⠉⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
+
+⠀Hi I'm testing the find command right now!

user/find.c

@@ -0,0 +1,147 @@
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+#include "kernel/fcntl.h"
+#include "stdbool.h"
+#include "kernel/fs.h"
+
+//goal: to recursively search thru directories to find a file
+// cite/research: https://www.geeksforgeeks.org/find-command-in-linux-with-examples/
+
+/**
+ * checks if pattern (file name or other symbols) matches target string
+ * patterns include: * or ?
+ *
+ * @param str file/directory name 
+ * @param pattern target provided
+ * @return true if file/directory matches name or pattern 
+ */
+bool matches(const char *str, const char *pattern) {
+	const char *tmp_pattern = pattern;
+	const char *tmp_str = str;
+	int star = -1;
+	int last_match = -1;
+
+	for (int i = 0; *tmp_str; i++) {
+		// move pattern pointer to next if a match or contains ? character
+		if (*tmp_pattern == *tmp_str || *tmp_pattern == '?') {
+			tmp_pattern++; 
+		// save position of * when found and save index of last match if string contains * character
+		} else if (*tmp_pattern == '*') {
+			// star position
+			star = i;
+			tmp_pattern++;
+			last_match = i;
+		// check if theres a mismatch after * character and revisit to last matched char
+		} else if (star != -1) {
+			i = last_match;
+			tmp_pattern = pattern + (tmp_pattern - pattern);
+		// no match found
+		} else {
+			return false;
+		}
+		tmp_str++;
+	}
+
+	// condition added to skip other chars after * in the pattern
+	while (*tmp_pattern == '*') {
+		tmp_pattern++;
+	}
+
+	// return if pattern matches strings
+	return *tmp_pattern == '\0';
+}
+
+/**
+ * finds path towards specific files or directories (some restrictions include)
+ *
+ * @param path starting directory for search
+ * @param flag settings or conditions 
+ * @param target pattern or file/directory name
+ */
+void find(const char *path, const char *flag, const char *target) {
+    int fd;
+    struct stat st;
+    struct dirent de;
+    char buf[512], *p;
+
+    if ((fd = open(path, O_RDONLY)) < 0) {
+        printf("find: cannot open %s\n", path);
+        return;
+    }
+
+    if (fstat(fd, &st) < 0) {
+        printf("find: cannot stat %s\n", path);
+        close(fd);
+        return;
+    }
+
+    // if it's a directory, traverse it
+    if (st.type == T_DIR) {
+        if (strlen(path) + 1 + DIRSIZ + 1 > sizeof(buf)) {
+            printf("find: path too long\n");
+            return;
+        }
+
+        strcpy(buf, path);
+        p = buf + strlen(buf);
+        *p++ = '/';
+
+      	while (read(fd, &de, sizeof(de)) == sizeof(de)) {
+            if (de.inum == 0)  // Skip invalid args
+                continue;
+
+            memmove(p, de.name, DIRSIZ);
+            p[DIRSIZ] = 0;
+
+            // skip "." and ".."
+            if (strcmp(de.name, ".") == 0 || strcmp(de.name, "..") == 0)
+                continue;
+
+            if (stat(buf, &st) < 0) {
+                printf("find: cannot stat %s\n", buf);
+                continue;
+            }
+
+			// prints all directory if argument is like "find path -type d"
+            if ((strcmp(target, "d") == 0) && (strcmp(flag, "-type") == 0) && (st.type == T_DIR)) {
+           		 printf("%s\n", buf);
+           	}
+
+			// prints all files if argument is like "find path -type f"
+           	if ((strcmp(target, "f") == 0) && (strcmp(flag, "-type") == 0) && (st.type == T_FILE)) {
+           		 printf("%s\n", buf);
+           	}
+
+            // if the file/directory name matches the target
+            // see if target includes any symbols like * or ?
+            if (strcmp(flag, "-name") == 0 && matches(de.name, target)) {
+            		printf("%s\n", buf);  // print if it matches
+            }
+
+            // recurse into it if it's a directory
+            if (st.type == T_DIR) {
+                find(buf, flag, target);
+            }
+        }
+    }
+
+    close(fd);
+}
+
+/**
+ * main method used for testing
+ *
+ * @param argc number of arguments
+ * @param argv array of arguments
+ * @return exit code
+ */
+int main(int argc, char *argv[]) {
+    if (argc < 3) {
+        printf("Usage: find <directory> <file_name>\n");
+        exit(1);
+    }
+
+    find(argv[1], argv[2], argv[3]);
+    exit(0);
+}