libopenbsd/closefrom.c: sync with sudo

diff --git a/libopenbsd/closefrom.c b/libopenbsd/closefrom.c
index ef7d611b003853b7955b7ec838fa0a9600ea7ea5..8f6608485ef6be1e4fecd5af2d4efa434d163855 100644 (file)
--- a/libopenbsd/closefrom.c
+++ b/libopenbsd/closefrom.c
@@ -1,5 +1,8 @@
 /*
- * Copyright (c) 2004-2005 Todd C. Miller <Todd.Miller@courtesan.com>
+ * SPDX-License-Identifier: ISC
+ *
+ * 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
@@ -14,96 +17,121 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#include "includes.h"
+/*
+ * 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 <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)
+#include <fcntl.h>
+#include <limits.h>
+#ifdef HAVE_PSTAT_GETPROC
+# include <sys/pstat.h>
 #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
+# include <dirent.h>
 #endif
 
-#ifndef OPEN_MAX
-# define OPEN_MAX      256
-#endif
+#include "openbsd.h"
 
-#if 0
-__unused static const char rcsid[] = "$Sudo: closefrom.c,v 1.11 2006/08/17 15:26:54 millert Exp $";
-#endif /* lint */
+#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.
  */
-#ifdef HAVE_FCNTL_CLOSEM
-void
-closefrom(int lowfd)
+static void
+closefrom_fallback(int lowfd)
 {
-    (void) fcntl(lowfd, F_CLOSEM, 0);
-}
+    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
 closefrom(int lowfd)
 {
-    long fd, maxfd;
-#if defined(HAVE_PROC_PID)
-    char fdpath[PATH_MAX], *endp;
-    struct dirent *dent;
+#if defined(HAVE_PSTAT_GETPROC)
+    struct pst_status pstat;
+#elif defined(HAVE_DIRFD)
+    const char *path;
     DIR *dirp;
-    int len;
+#endif
 
-    /* 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))) {
+    /* 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)
+    /*
+     * EOVERFLOW is not a fatal error for the fields we use.
+     * See the "EOVERFLOW Error" section of pstat_getvminfo(3).
+     */
+    if (pstat_getproc(&pstat, sizeof(pstat), 0, getpid()) != -1 ||
+       errno == EOVERFLOW) {
+       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 macOS) if it exists. */
+# ifdef __APPLE__
+    path = _PATH_DEV "fd";
+# else
+    path = "/proc/self/fd";
+# endif
+    if ((dirp = opendir(path)) != NULL) {
+       struct dirent *dent;
        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);
+           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);
-    } 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);
+       return;
     }
+#endif /* HAVE_DIRFD */
+
+    /* Do things the slow way. */
+    closefrom_fallback(lowfd);
 }
-#endif /* !HAVE_FCNTL_CLOSEM */
+
 #endif /* HAVE_CLOSEFROM */