Merge branch 'cow' into net

Conflicts:
	.gitignore
	Makefile
	conf/lab.mk
	kernel/defs.h
	kernel/syscall.c
	kernel/vm.c
	user/pingpong.c
	user/user.h
	user/usys.pl

1 files changed, 84 insertions, 0 deletions

diff --git a/user/find.c b/user/find.c
new file mode 100644
index 0000000..e185e9d
--- /dev/null
+++ b/user/find.c
@@ -0,0 +1,84 @@
+#include "kernel/types.h"
+
+#include "kernel/fcntl.h"
+#include "kernel/fs.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+char*
+fmtname(char* path)
+{
+  char* p;
+
+  // Find first character after last slash.
+  for (p = path + strlen(path); p >= path && *p != '/'; p--)
+    ;
+  p++;
+  return p;
+}
+
+void
+find(char* root_path, char* filename)
+{
+  static char buf[512];
+  char* p;
+  int fd;
+  struct dirent de;
+  struct stat st;
+
+  if ((fd = open(root_path, O_RDONLY)) < 0) {
+    fprintf(2, "find: cannot open %s\n", root_path);
+    return;
+  }
+  if (fstat(fd, &st) < 0) {
+    fprintf(2, "find: cannot stat %s\n", root_path);
+    close(fd);
+    return;
+  }
+
+  switch (st.type) {
+    case T_FILE:
+      if (!strcmp(fmtname(root_path), filename)) {
+        printf("%s\n", root_path);
+      }
+      break;
+    case T_DIR:
+      if (strlen(root_path) + 1 + DIRSIZ + 1 > sizeof(buf)) {
+        printf("find: path too long\n");
+        break;
+      }
+
+      strcpy(buf, root_path);
+
+      p = buf + strlen(buf);
+      *p++ = '/';
+      while (read(fd, &de, sizeof(de)) == sizeof(de)) {
+        if (de.inum == 0)
+          continue;
+        memmove(p, de.name, DIRSIZ);
+        p[DIRSIZ] = '\0';
+
+        // printf("i'm finding %s!\n", fmtname(buf));
+
+        if (!strcmp(fmtname(buf), ".") || !strcmp(fmtname(buf), "..")) {
+          continue;
+        }
+
+        find(buf, filename);
+      }
+  }
+  close(fd);
+}
+
+int
+main(int argc, char* argv[])
+{
+  if (argc < 3) {
+    fprintf(2, "usage: find [root_path] filename...\n");
+    exit(1);
+  }
+
+  for (int i = 2; i < argc; i++) {
+    find(argv[1], argv[i]);
+  }
+}