Add closefrom(2) from openssh-portable

[opendoas.git] / libopenbsd / closefrom.c

diff --git a/libopenbsd/closefrom.c b/libopenbsd/closefrom.c
new file mode 100644 (file)
index 0000000..9380b33
--- /dev/null
+++ b/libopenbsd/closefrom.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2004-2005 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * 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.
+ */
+
+#include "includes.h"
+
+#ifndef HAVE_CLOSEFROM
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <unistd.h>
+#include <stdio.h>
+#ifdef HAVE_FCNTL_H
+# include <fcntl.h>
+#endif
+#include <limits.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#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
+
+#ifndef OPEN_MAX
+# define OPEN_MAX      256
+#endif
+
+#if 0
+__unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
+#endif /* lint */
+
+/*
+ * Close all file descriptors greater than or equal to lowfd.
+ */
+#ifdef HAVE_FCNTL_CLOSEM
+void
+closefrom(int lowfd)
+{
+    (void) fcntl(lowfd, F_CLOSEM, 0);
+}
+#else
+void
+closefrom(int lowfd)
+{
+    long fd, maxfd;
+#if defined(HAVE_DIRFD) && defined(HAVE_PROC_PID)
+    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 > 0 && (size_t)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);
+       }
+       (void) closedir(dirp);
+    } else
+#endif
+    {
+       /*
+        * 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);
+#else
+       maxfd = getdtablesize();
+#endif /* HAVE_SYSCONF */
+       if (maxfd < 0)
+           maxfd = OPEN_MAX;
+
+       for (fd = lowfd; fd < maxfd; fd++)
+           (void) close((int) fd);
+    }
+}
+#endif /* !HAVE_FCNTL_CLOSEM */
+#endif /* HAVE_CLOSEFROM */