Move openat() emulation to lib/util and at unlinkat() emulation.

MANIFEST

@@ -119,6 +119,7 @@ lib/util/mksigname.c
 lib/util/mksigname.h
 lib/util/mktemp.c
 lib/util/nanosleep.c
+lib/util/openat.c
 lib/util/parseln.c
 lib/util/pipe2.c
 lib/util/progname.c
@@ -195,6 +196,7 @@ lib/util/sudo_dso.c
 lib/util/term.c
 lib/util/ttyname_dev.c
 lib/util/ttysize.c
+lib/util/unlinkat.c
 lib/util/util.exp.in
 lib/util/utimens.c
 lib/util/vsyslog.c

config.h.in

@@ -861,6 +861,9 @@
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the `unlinkat' function. */
+#undef HAVE_UNLINKAT
+
 /* Define to 1 if you have the `unsetenv' function. */
 #undef HAVE_UNSETENV
 

configure

@@ -2881,7 +2881,6 @@ as_fn_append ac_func_list " killpg"
 as_fn_append ac_func_list " nl_langinfo"
 as_fn_append ac_func_list " pread"
 as_fn_append ac_func_list " pwrite"
-as_fn_append ac_func_list " openat"
 as_fn_append ac_func_list " faccessat"
 as_fn_append ac_func_list " wordexp"
 as_fn_append ac_func_list " getauxval"
@@ -19211,8 +19210,6 @@ done
 
 
 
-
-
 case "$host_os" in
     hpux*)
 	if test X"$ac_cv_func_pread" = X"yes"; then
@@ -20444,6 +20441,58 @@ esac
 fi
 
 
+fi
+done
+
+for ac_func in openat
+do :
+  ac_fn_c_check_func "$LINENO" "openat" "ac_cv_func_openat"
+if test "x$ac_cv_func_openat" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_OPENAT 1
+_ACEOF
+
+else
+
+    case " $LIBOBJS " in
+  *" openat.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS openat.$ac_objext"
+ ;;
+esac
+
+
+    for _sym in sudo_openat; do
+	COMPAT_EXP="${COMPAT_EXP}${_sym}
+"
+    done
+
+
+fi
+done
+
+for ac_func in unlinkat
+do :
+  ac_fn_c_check_func "$LINENO" "unlinkat" "ac_cv_func_unlinkat"
+if test "x$ac_cv_func_unlinkat" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_UNLINKAT 1
+_ACEOF
+
+else
+
+    case " $LIBOBJS " in
+  *" unlinkat.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS unlinkat.$ac_objext"
+ ;;
+esac
+
+
+    for _sym in sudo_unlinkat; do
+	COMPAT_EXP="${COMPAT_EXP}${_sym}
+"
+    done
+
+
 fi
 done
 

configure.ac

@@ -2506,7 +2506,7 @@ dnl
 dnl Function checks
 dnl
 AC_FUNC_GETGROUPS
-AC_CHECK_FUNCS_ONCE([fexecve killpg nl_langinfo pread pwrite openat faccessat wordexp getauxval])
+AC_CHECK_FUNCS_ONCE([fexecve killpg nl_langinfo pread pwrite faccessat wordexp getauxval])
 case "$host_os" in
     hpux*)
 	if test X"$ac_cv_func_pread" = X"yes"; then
@@ -2720,6 +2720,14 @@ AC_CHECK_FUNCS(nanosleep, [], [
 	SUDO_APPEND_COMPAT_EXP(sudo_nanosleep)
     ])
 ])
+AC_CHECK_FUNCS([openat], [], [
+    AC_LIBOBJ(openat)
+    SUDO_APPEND_COMPAT_EXP(sudo_openat)
+])
+AC_CHECK_FUNCS([unlinkat], [], [
+    AC_LIBOBJ(unlinkat)
+    SUDO_APPEND_COMPAT_EXP(sudo_unlinkat)
+])
 AC_CHECK_FUNCS([pipe2], [], [
     AC_LIBOBJ(pipe2)
     SUDO_APPEND_COMPAT_EXP(sudo_pipe2)

include/sudo_compat.h

@@ -479,7 +479,12 @@ __dso_public int sudo_mkstemps(char *path, int slen);
 __dso_public int sudo_nanosleep(const struct timespec *timeout, struct timespec *remainder);
 #undef nanosleep
 # define nanosleep(_a, _b) sudo_nanosleep((_a), (_b))
-#endif
+#endif /* HAVE_NANOSLEEP */
+#ifndef HAVE_OPENAT
+__dso_public int sudo_openat(int dfd, const char *path, int flags, mode_t mode);
+# undef openat
+# define openat(_a, _b, _c, _d) sudo_openat((_a), (_b), (_c), (_d))
+#endif /* HAVE_OPENAT */
 #ifndef HAVE_PW_DUP
 __dso_public struct passwd *sudo_pw_dup(const struct passwd *pw);
 # undef pw_dup
@@ -530,5 +535,10 @@ __dso_public int sudo_pipe2(int fildes[2], int flags);
 # undef pipe2
 # define pipe2(_a, _b) sudo_pipe2((_a), (_b))
 #endif /* HAVE_PIPE2 */
+#ifndef HAVE_UNLINKAT
+__dso_public int sudo_unlinkat(int dfd, const char *path, int flag);
+# undef unlinkat
+# define unlinkat(_a, _b, _c) sudo_unlinkat((_a), (_b), (_c))
+#endif /* HAVE_UNLINKAT */
 
 #endif /* SUDO_COMPAT_H */

lib/util/openat.c

@@ -0,0 +1,65 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2015, 2019 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>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "sudo_compat.h"
+
+#ifndef HAVE_OPENAT
+int
+sudo_openat(int dfd, const char *path, int flags, mode_t mode)
+{
+    int fd, odfd;
+
+    if (dfd == AT_FDCWD)
+	return open(path, flags, mode);
+
+    /* Save cwd */
+    if ((odfd = open(".", O_RDONLY)) == -1)
+	return -1;
+
+    if (fchdir(dfd) == -1) {
+	close(odfd);
+	return -1;
+    }
+
+    fd = open(path, flags, mode);
+
+    /* Restore cwd */
+    if (fchdir(odfd) == -1) {
+	/* Should not happen */
+	if (fd != -1) {
+	    close(fd);
+	    fd = -1;
+	}
+    }
+    close(odfd);
+
+    return fd;
+}
+#endif /* HAVE_OPENAT */

lib/util/unlinkat.c

@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2019 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>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "sudo_compat.h"
+
+#ifndef HAVE_UNLINKAT
+int
+sudo_unlinkat(int dfd, const char *path, int flag)
+{
+    int odfd, ret;
+
+    if (dfd == AT_FDCWD)
+	return unlink(path);
+
+    /* Save cwd */
+    if ((odfd = open(".", O_RDONLY)) == -1)
+	return -1;
+
+    if (fchdir(dfd) == -1) {
+	close(odfd);
+	return -1;
+    }
+
+    ret = unlink(path);
+
+    /* Restore cwd */
+    if (fchdir(odfd) == -1) {
+	/* Should not happen */
+	ret = -1;
+    }
+    close(odfd);
+
+    return ret;
+}
+#endif /* HAVE_UNLINKAT */

src/sudo_edit.c

@@ -262,37 +262,6 @@ sudo_edit_mktemp(const char *ofile, char **tfile)
     debug_return_int(tfd);
 }
 
-#ifndef HAVE_OPENAT
-static int
-sudo_openat(int dfd, const char *path, int flags, mode_t mode)
-{
-    int fd, odfd;
-    debug_decl(sudo_openat, SUDO_DEBUG_EDIT)
-
-    if (dfd == AT_FDCWD)
-	debug_return_int(open(path, flags, mode));
-
-    /* Save cwd */
-    if ((odfd = open(".", O_RDONLY)) == -1)
-	debug_return_int(-1);
-
-    if (fchdir(dfd) == -1) {
-	close(odfd);
-	debug_return_int(-1);
-    }
-
-    fd = open(path, flags, mode);
-
-    /* Restore cwd */
-    if (fchdir(odfd) == -1)
-	sudo_fatal(U_("unable to restore current working directory"));
-    close(odfd);
-
-    debug_return_int(fd);
-}
-#define openat sudo_openat
-#endif /* HAVE_OPENAT */
-
 #ifdef O_NOFOLLOW
 static int
 sudo_edit_openat_nofollow(int dfd, char *path, int oflags, mode_t mode)