add directory study

study/linux-travel/MINIX-1.5/1.5/Source/commands/passwd.c

@@ -0,0 +1,104 @@
+/* passwd - change a passwd		Author: Adri Koppes */
+
+#include <sys/types.h>
+#include <fcntl.h>
+#include <string.h>
+#include <signal.h>
+#include <pwd.h>
+
+char pwd_file[] = "/etc/passwd";
+char pw_tmp[] = "/etc/pwtemp";
+char bad[] = "Permission denied\n";
+char buf[512];
+
+main(argc, argv)
+int argc;
+char *argv[];
+{
+  int uid, cn, n;
+  int fpin, fpout;
+  long salt;
+  struct passwd *pwd, *getpwnam(), *getpwuid(), *getpwent();
+  char name[9], password[14], sl[2];
+  char *getpass(), *crypt(), *itoa();
+
+  uid = getuid();
+
+  if (!access(pw_tmp, 0)) {
+	std_err("Temporary file in use.\nTry again later\n");
+	exit(1);
+  }
+  if (argc < 2) {
+	pwd = getpwuid(uid);
+	strcpy(name, pwd->pw_name);
+  } else {
+	strcpy(name, argv[1]);
+	pwd = getpwnam(name);
+  }
+  if (!pwd || ((uid != pwd->pw_uid) && uid)) {
+	std_err(bad);
+	exit(1);
+  }
+  signal(SIGHUP, SIG_IGN);
+  signal(SIGINT, SIG_IGN);
+  signal(SIGQUIT, SIG_IGN);
+  signal(SIGTERM, SIG_IGN);
+  prints("Changing password for %s\n", name);
+  if (pwd->pw_passwd[0] && uid)
+	if (strcmp(pwd->pw_passwd, crypt(getpass("Old password: "), pwd->pw_passwd))) {
+		std_err(bad);
+		exit(1);
+	}
+  strcpy(password, getpass("New password: "));
+  if (password[0] == '\0') {
+	std_err("password cannot be null\n");
+	exit(1);
+  }
+  if (strcmp(password, getpass("Retype password: "))) {
+	std_err("Passwords don't match\n");
+	exit(1);
+  }
+  time(&salt);
+  sl[0] = (salt & 077) + '.';
+  sl[1] = ((salt >> 6) & 077) + '.';
+  for (cn = 0; cn < 2; cn++) {
+	if (sl[cn] > '9') sl[cn] += 7;
+	if (sl[cn] > 'Z') sl[cn] += 6;
+  }
+  if (password[0]) strcpy(password, crypt(password, sl));
+  umask(0);
+  close(1);
+  fpout = creat(pw_tmp, 0600);
+  if (fpout != 1) {
+	std_err("Can't create temporary file\n");
+	exit(1);
+  }
+  setpwent();
+  while ((pwd = getpwent()) != 0) {
+	if (!strcmp(name, pwd->pw_name)) pwd->pw_passwd = password;
+	prints("%s:%s:%s:", pwd->pw_name, pwd->pw_passwd, itoa(pwd->pw_uid));
+	prints("%s:%s:%s:%s\n", itoa(pwd->pw_gid), pwd->pw_gecos, pwd->pw_dir,
+	       pwd->pw_shell);
+  }
+  endpwent();
+  close(0);
+  if ((fpin = open(pw_tmp, 0)) != 0) {
+	std_err("Can't reopen temporary file\n");
+	exit(1);
+  }
+  close(fpout);
+  if ((fpout = open(pwd_file, O_RDWR)) < 0) {
+	std_err("Can't recreate password file\n");
+	unlink(pw_tmp);
+	exit(1);
+  }
+  while (1) {
+	n = read(fpin, buf, 512);
+	if (n <= 0) break;
+	write(1, buf, n);
+  }
+
+  close(fpin);
+  close(fpout);
+  unlink(pw_tmp);
+}