optional added

user/find.c

@@ -3,20 +3,48 @@
 #include "kernel/types.h"
 #include "user/user.h"
 
-void find(char *path, char *filename) {
-  int fd = open(path, 0);
+int match_pattern(const char *name, const char *pattern) {
+  const char *star = 0;
+  const char *name_ptr = name;
+  const char *pattern_ptr = pattern;
+
+  while (1) {
+    if (*pattern_ptr == '*') {
+      star = pattern_ptr++;
+      name_ptr = name;
+      continue;
+    }
+
+    if (!*name)
+      return (!*pattern_ptr || (star && !*++pattern_ptr));
+    if (*pattern_ptr == '?' || *pattern_ptr == *name) {
+      pattern_ptr++;
+      name++;
+      continue;
+    }
+
+    if (star) {
+      pattern_ptr = star + 1;
+      name = ++name_ptr;
+      continue;
+    }
+    return 0;
+  }
+}
+
+void find(char *path, char *pattern) {
   char buf[512], *p;
+  int fd;
   struct dirent de;
   struct stat st;
 
-  if (fd < 0 || strlen(path) + 1 + DIRSIZ + 1 >= sizeof(buf)) {
-    fprintf(2, "find: Invalid path: %s\n", path);
-    // close(fd);
+  if ((fd = open(path, 0)) < 0) {
+    fprintf(2, "find: cannot open %s\n", path);
     return;
   }
 
   if (fstat(fd, &st) < 0) {
-    fprintf(2, "find: Failed to stat %s\n", path);
+    fprintf(2, "find: cannot stat %s\n", path);
     close(fd);
     return;
   }
@@ -27,36 +55,42 @@ void find(char *path, char *filename) {
     return;
   }
 
-  strncpy(buf, path, strlen(path) + 1);
-  p = buf + strlen(path);
+  if (strlen(path) + 1 + DIRSIZ + 1 > sizeof buf) {
+    fprintf(2, "find: path too long\n");
+    close(fd);
+    return;
+  }
+
+  strcpy(buf, path);
+  p = buf + strlen(buf);
   *p++ = '/';
+
   while (read(fd, &de, sizeof(de)) == sizeof(de)) {
-    if (de.inum == 0)
-      continue;
-    if (!strcmp(de.name, ".") || !strcmp(de.name, ".."))
+    if (de.inum == 0 || !strcmp(de.name, ".") || !strcmp(de.name, ".."))
       continue;
 
     memmove(p, de.name, DIRSIZ);
     p[DIRSIZ] = 0;
 
     if (stat(buf, &st) < 0) {
-      fprintf(2, "find: Failed to stat %s\n", buf);
+      fprintf(2, "find: cannot stat %s\n", buf);
       continue;
     }
 
     if (st.type == T_DIR) {
-      find(buf, filename);
+      find(buf, pattern);
     } else if (st.type == T_FILE) {
-      if (!strcmp(filename, "*") || !strcmp(filename, de.name)) {
-        printf("%s\n", buf);
+      if (match_pattern(de.name, pattern)) {
+        fprintf(1, "%s\n", buf);
       }
     }
   }
+  close(fd);
 }
 
 int main(int argc, char *argv[]) {
   if (argc != 3) {
-    printf("Usage: find path filename\n");
+    fprintf(2, "Usage: find <path> <pattern>\n");
     exit(1);
   }
   find(argv[1], argv[2]);