1 files changed, 131 insertions, 0 deletions
diff --git a/lib/util/closefrom.c b/lib/util/closefrom.c
new file mode 100644
index 0000000..6cfe320
--- /dev/null
+++ b/lib/util/closefrom.c
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2004-2005, 2007, 2010, 2012-2015, 2017-2018
+ *	Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#ifndef HAVE_CLOSEFROM
+
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <limits.h>
+#ifdef HAVE_PSTAT_GETPROC
+# include <sys/pstat.h>
+#else
+# include <dirent.h>
+#endif
+
+#include "sudo_compat.h"
+#include "pathnames.h"
+
+#ifndef _POSIX_OPEN_MAX
+# define _POSIX_OPEN_MAX	20
+#endif
+
+/*
+ * Close all file descriptors greater than or equal to lowfd.
+ * This is the expensive (fallback) method.
+ */
+static void
+closefrom_fallback(int lowfd)
+{
+    long fd, maxfd;
+
+    /*
+     * Fall back on sysconf(_SC_OPEN_MAX).  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.
+     */
+    maxfd = sysconf(_SC_OPEN_MAX);
+    if (maxfd < 0)
+	maxfd = _POSIX_OPEN_MAX;
+
+    for (fd = lowfd; fd < maxfd; fd++) {
+#ifdef __APPLE__
+	/* Avoid potential libdispatch crash when we close its fds. */
+	(void) fcntl((int) fd, F_SETFD, FD_CLOEXEC);
+#else
+	(void) close((int) fd);
+#endif
+    }
+}
+
+/*
+ * Close all file descriptors greater than or equal to lowfd.
+ * We try the fast way first, falling back on the slow method.
+ */
+void
+sudo_closefrom(int lowfd)
+{
+#if defined(HAVE_PSTAT_GETPROC)
+    struct pst_status pstat;
+#elif defined(HAVE_DIRFD)
+    const char *path;
+    DIR *dirp;
+#endif
+
+    /* Try the fast method first, if possible. */
+#if defined(HAVE_FCNTL_CLOSEM)
+    if (fcntl(lowfd, F_CLOSEM, 0) != -1)
+	return;
+#endif
+#if defined(HAVE_PSTAT_GETPROC)
+    if (pstat_getproc(&pstat, sizeof(pstat), 0, getpid()) != -1) {
+	int fd;
+
+	for (fd = lowfd; fd <= pstat.pst_highestfd; fd++)
+	    (void) close(fd);
+	return;
+    }
+#elif defined(HAVE_DIRFD)
+    /* Use /proc/self/fd (or /dev/fd on FreeBSD) if it exists. */
+# if defined(__FreeBSD__) || defined(__APPLE__)
+    path = _PATH_DEV "fd";
+# else
+    path = "/proc/self/fd";
+# endif
+    if ((dirp = opendir(path)) != NULL) {
+	struct dirent *dent;
+	while ((dent = readdir(dirp)) != NULL) {
+	    const char *errstr;
+	    int fd = strtonum(dent->d_name, lowfd, INT_MAX, &errstr);
+	    if (errstr == NULL && fd != dirfd(dirp)) {
+# ifdef __APPLE__
+		/* Avoid potential libdispatch crash when we close its fds. */
+		(void) fcntl(fd, F_SETFD, FD_CLOEXEC);
+# else
+		(void) close(fd);
+# endif
+	    }
+	}
+	(void) closedir(dirp);
+	return;
+    }
+#endif /* HAVE_DIRFD */
+
+    /* Do things the slow way. */
+    closefrom_fallback(lowfd);
+}
+
+#endif /* HAVE_CLOSEFROM */