Initial work to set CLOEXEC on all possible fds

Still to go: some pipes, all stdio files.

1 files changed, 37 insertions, 4 deletions

diff --git a/src/common/compat.c b/src/common/compat.c
index b7f4f17ca..e3a76e8df 100644
--- a/src/common/compat.c
+++ b/src/common/compat.c
@@ -101,6 +101,23 @@
 #include "strlcat.c"
 #endif
 
+/** As open(path, flags, mode), but return an fd with the close-on-exec mode
+ * set. */
+int
+tor_open_cloexec(const char *path, int flags, unsigned mode)
+{
+#ifdef O_CLOEXEC
+  return open(path, flags|O_CLOEXEC, mode);
+#else
+  int fd = open(path, flags, mode);
+#ifdef FD_CLOEXEC
+  if (fd >= 0)
+        fcntl(s, F_SETFD, FD_CLOEXEC);
+#endif
+  return fd;
+#endif
+}
+
 #ifdef HAVE_SYS_MMAN_H
 /** Try to create a memory mapping for <b>filename</b> and return it.  On
  * failure, return NULL.  Sets errno properly, using ERANGE to mean
@@ -116,7 +133,7 @@ tor_mmap_file(const char *filename)
 
   tor_assert(filename);
 
-  fd = open(filename, O_RDONLY, 0);
+  fd = tor_open_cloexec(filename, O_RDONLY, 0);
   if (fd<0) {
     int save_errno = errno;
     int severity = (errno == ENOENT) ? LOG_INFO : LOG_WARN;
@@ -685,7 +702,7 @@ tor_lockfile_lock(const char *filename, int blocking, int *locked_out)
   *locked_out = 0;
 
   log_info(LD_FS, "Locking \"%s\"", filename);
-  fd = open(filename, O_RDWR|O_CREAT|O_TRUNC, 0600);
+  fd = tor_open_cloexec(filename, O_RDWR|O_CREAT|O_TRUNC, 0600);
   if (fd < 0) {
     log_warn(LD_FS,"Couldn't open \"%s\" for locking: %s", filename,
              strerror(errno));
@@ -904,8 +921,15 @@ mark_socket_open(int s)
 int
 tor_open_socket(int domain, int type, int protocol)
 {
-  int s = socket(domain, type, protocol);
+  int s;
+#ifdef SOCK_CLOEXEC
+  type |= SOCK_CLOEXEC;
+#endif
+  s = socket(domain, type, protocol);
   if (s >= 0) {
+#ifdef FD_CLOEXEC
+    fcntl(s, F_SETFD, FD_CLOEXEC);
+#endif
     socket_accounting_lock();
     ++n_sockets_open;
     mark_socket_open(s);
@@ -918,8 +942,17 @@ tor_open_socket(int domain, int type, int protocol)
 int
 tor_accept_socket(int sockfd, struct sockaddr *addr, socklen_t *len)
 {
-  int s = accept(sockfd, addr, len);
+  int s;
+#if defined(HAVE_ACCEPT4) && defined(SOCK_CLOEXEC)
+#define LINUX_CLOEXEC_ACCEPT
+  s = accept4(sockfd, addr, len, SOCK_CLOEXEC);
+#else
+  s = accept(sockfd, addr, len);
+#endif
   if (s >= 0) {
+#if !defined(LINUX_CLOEXEC_ACCEPT) && defined(FD_CLOEXEC)
+    fcntl(s, F_SETFD, FD_CLOEXEC);
+#endif
     socket_accounting_lock();
     ++n_sockets_open;
     mark_socket_open(s);