From e2a573d6cce4c9e1298236d0e2e0518e2e94ac9b Mon Sep 17 00:00:00 2001
From: "Todd C. Miller" <Todd.Miller@courtesan.com>
Date: Tue, 1 Jun 2004 16:44:14 +0000
Subject: [PATCH] If there is a /proc/$$/fd directory, behave like the Solaris
closefrom() and only close the descriptors listed therein.
---
closefrom.c | 76 ++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 60 insertions(+), 16 deletions(-)
diff --git a/closefrom.c b/closefrom.c
index 05bef4945..6cc7a8ec1 100644
--- a/closefrom.c
+++ b/closefrom.c
@@ -14,41 +14,85 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
+#include "config.h"
+
#include <sys/types.h>
-#include <limits.h>
+#include <sys/param.h>
#include <unistd.h>
+#include <stdio.h>
+#ifdef STDC_HEADERS
+# include <stdlib.h>
+# include <stddef.h>
+#else
+# ifdef HAVE_STDLIB_H
+# include <stdlib.h>
+# endif
+#endif /* STDC_HEADERS */
+#ifdef HAVE_DIRENT_H
+# include <dirent.h>
+# define NAMLEN(dirent) strlen((dirent)->d_name)
+#else
+# define dirent direct
+# define NAMLEN(dirent) (dirent)->d_namlen
+# ifdef HAVE_SYS_NDIR_H
+# include <sys/ndir.h>
+# endif
+# ifdef HAVE_SYS_DIR_H
+# include <sys/dir.h>
+# endif
+# ifdef HAVE_NDIR_H
+# include <ndir.h>
+# endif
+#endif
-#include "config.h"
+#include "sudo.h"
+
+#ifndef dirfd
+# define dirfd(dirp) ((dirp)->dd_fd)
+#endif
#ifndef lint
static const char rcsid[] = "$Sudo$";
#endif /* lint */
-#ifndef OPEN_MAX
-# define OPEN_MAX 256
-#endif
-
/*
* Close all file descriptors greater than or equal to lowfd.
- * We cannot rely on resource limits since it is possible to
- * open a file descriptor and then drop the rlimit such that
- * it is below the open fd.
*/
void
closefrom(lowfd)
int lowfd;
{
long fd, maxfd;
+ char fdpath[PATH_MAX], *endp;
+ struct dirent *dent;
+ DIR *dirp;
+ int len;
+ /* Check for a /proc/$$/fd directory. */
+ len = snprintf(fdpath, sizeof(fdpath), "/proc/%ld/fd", (long)getpid());
+ if (len != -1 && len <= sizeof(fdpath) && (dirp = opendir(fdpath))) {
+ while ((dent = readdir(dirp)) != NULL) {
+ fd = strtol(dent->d_name, &endp, 10);
+ if (dent->d_name != endp && *endp == '\0' &&
+ fd >= 0 && fd < INT_MAX && fd >= lowfd && fd != dirfd(dirp))
+ (void) close((int) fd);
+ }
+ closedir(dirp);
+ } else {
+ /*
+ * Fall back on sysconf() or getdtablesize(). We avoid checking
+ * resource limits since it is possible to open a file descriptor
+ * and then drop the rlimit such that it is below the open fd.
+ */
#ifdef HAVE_SYSCONF
- maxfd = sysconf(_SC_OPEN_MAX);
+ maxfd = sysconf(_SC_OPEN_MAX);
#else
- maxfd = getdtablesize();
+ maxfd = getdtablesize();
#endif /* HAVE_SYSCONF */
- if (maxfd < 0)
- maxfd = OPEN_MAX;
+ if (maxfd < 0)
+ maxfd = OPEN_MAX;
- for (fd = lowfd; fd < maxfd; fd++)
- (void) close(fd);
- return;
+ for (fd = lowfd; fd < maxfd; fd++)
+ (void) close((int) fd);
+ }
}
--
2.40.0