[PATCH 1/6] isolation, util: Fold close_open_files() into isolate_initial()

[David Gibson <david@gibson.dropbear.id.au>]

Most functions in util.c are, well, utilities, that are useful in a bunch
of places.  close_open_files(), however, is very specific, it's only called
from isolate_initial(), and really only can be called from there - it's
logic encodes a very specific action we want to take at that point.

So, remove it from util.c and fold into isolate_initial().

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 isolation.c | 37 ++++++++++++++++++++++++++++++++++++-
 util.c      | 49 -------------------------------------------------
 util.h      |  1 -
 3 files changed, 36 insertions(+), 51 deletions(-)

diff --git a/isolation.c b/isolation.c
index c868e668..07b281bb 100644
--- a/isolation.c
+++ b/isolation.c
@@ -58,6 +58,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <getopt.h>
 #include <grp.h>
 #include <inttypes.h>
 #include <limits.h>
@@ -88,6 +89,7 @@
 #include "passt.h"
 #include "log.h"
 #include "isolation.h"
+#include "conf.h"
 
 #define CAP_VERSION	_LINUX_CAPABILITY_VERSION_3
 #define CAP_WORDS	_LINUX_CAPABILITY_U32S_3
@@ -204,6 +206,9 @@ static int move_root(void)
  */
 void isolate_initial(int argc, char **argv)
 {
+	const struct option optfd[] = { { "fd", required_argument, NULL, 'F' },
+					{ 0 }, };
+	int name, rc, fd_tap = -1;
 	uint64_t keep;
 
 	/* We want to keep CAP_NET_BIND_SERVICE in the initial
@@ -244,7 +249,37 @@ void isolate_initial(int argc, char **argv)
 
 	drop_caps_ep_except(keep);
 
-	close_open_files(argc, argv);
+	do {
+		name = getopt_long(argc, argv, "-:F:", optfd, NULL);
+
+		if (name == 'F')
+			fd_tap = conf_tap_fd(optarg);
+	} while (name != -1);
+
+	if (fd_tap == -1) {
+		rc = close_range(STDERR_FILENO + 1, ~0U, CLOSE_RANGE_UNSHARE);
+	} else if (fd_tap == STDERR_FILENO + 1) { /* Still a single range */
+		rc = close_range(STDERR_FILENO + 2, ~0U, CLOSE_RANGE_UNSHARE);
+	} else {
+		rc = close_range(STDERR_FILENO + 1, fd_tap - 1,
+				 CLOSE_RANGE_UNSHARE);
+		if (!rc)
+			rc = close_range(fd_tap + 1, ~0U, CLOSE_RANGE_UNSHARE);
+	}
+
+	if (rc) {
+		if (errno == ENOSYS || errno == EINVAL) {
+			/* This probably means close_range() or the
+			 * CLOSE_RANGE_UNSHARE flag is not supported by the
+			 * kernel.  Not much we can do here except carry on and
+			 * hope for the best.
+			 */
+			warn(
+"Can't use close_range() to ensure no files leaked by parent");
+		} else {
+			die_perror("Failed to close files leaked by parent");
+		}
+	}
 }
 
 /**
diff --git a/util.c b/util.c
index 4bc5d6f8..ce5021a9 100644
--- a/util.c
+++ b/util.c
@@ -26,7 +26,6 @@
 #include <stdbool.h>
 #include <linux/errqueue.h>
 #include <linux/in6.h>
-#include <getopt.h>
 
 #include "linux_dep.h"
 #include "util.h"
@@ -38,7 +37,6 @@
 #include "epoll_ctl.h"
 #include "pasta.h"
 #include "serialise.h"
-#include "conf.h"
 #ifdef HAS_GETRANDOM
 #include <sys/random.h>
 #endif
@@ -924,53 +922,6 @@ const char *str_ee_origin(const struct sock_extended_err *ee)
 	return "<invalid>";
 }
 
-/**
- * close_open_files() - Close leaked files, but not --fd, stdin, stdout, stderr
- * @argc:	Argument count
- * @argv:	Command line options, as we need to skip any file given via --fd
- */
-void close_open_files(int argc, char **argv)
-{
-	const struct option optfd[] = { { "fd", required_argument, NULL, 'F' },
-					{ 0 },
-				      };
-	long fd = -1;
-	int name, rc;
-
-	do {
-		name = getopt_long(argc, argv, "-:F:", optfd, NULL);
-
-		if (name == 'F')
-			fd = conf_tap_fd(optarg);
-	} while (name != -1);
-
-	if (fd == -1) {
-		rc = close_range(STDERR_FILENO + 1, ~0U, CLOSE_RANGE_UNSHARE);
-	} else if (fd == STDERR_FILENO + 1) { /* Still a single range */
-		rc = close_range(STDERR_FILENO + 2, ~0U, CLOSE_RANGE_UNSHARE);
-	} else {
-		rc = close_range(STDERR_FILENO + 1, fd - 1,
-				 CLOSE_RANGE_UNSHARE);
-		if (!rc)
-			rc = close_range(fd + 1, ~0U, CLOSE_RANGE_UNSHARE);
-	}
-
-	if (rc) {
-		if (errno == ENOSYS || errno == EINVAL) {
-			/* This probably means close_range() or the
-			 * CLOSE_RANGE_UNSHARE flag is not supported by the
-			 * kernel.  Not much we can do here except carry on and
-			 * hope for the best.
-			 */
-			warn(
-"Can't use close_range() to ensure no files leaked by parent");
-		} else {
-			die_perror("Failed to close files leaked by parent");
-		}
-	}
-
-}
-
 /**
  * snprintf_check() - snprintf() wrapper, checking for truncation and errors
  * @str:	Output buffer
diff --git a/util.h b/util.h
index 90e8a20d..2435f536 100644
--- a/util.h
+++ b/util.h
@@ -168,7 +168,6 @@ intmax_t read_file_integer(const char *path, intmax_t fallback);
 int write_remainder(int fd, const struct iovec *iov, size_t iovcnt,
 		    size_t skip, size_t length);
 int read_remainder(int fd, const struct iovec *iov, size_t cnt, size_t skip);
-void close_open_files(int argc, char **argv);
 bool snprintf_check(char *str, size_t size, const char *format, ...);
 long clamped_scale(long x, long y, long lo, long hi, long f);
 
-- 
2.55.0