From: Karel Zak <kzak@redhat.com>
Date: Thu, 7 Nov 2024 11:26:25 +0000 (+0100)
Subject: nsenter: support empty environ[]
X-Git-Tag: v2.40.3~62
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ee8235a65edd01a4899f2557dc9aa2cb9c6de7bc;p=thirdparty%2Futil-linux.git

nsenter: support empty environ[]

There is no error when the /proc/#/environ file does not contain any
NAME=value items.

Backport from master (v2.41) branch.

Fixes: https://github.com/util-linux/util-linux/issues/3270
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/lib/env.c b/lib/env.c
index 24ae90d00..f35006f3a 100644
--- a/lib/env.c
+++ b/lib/env.c
@@ -93,6 +93,7 @@ struct ul_env_list *env_from_fd(int fd)
 	ssize_t rc = 0;
 	struct ul_env_list *ls = NULL;
 
+	errno = 0;
 	if ((rc = read_all_alloc(fd, &buf)) < 1)
 		return NULL;
 	buf[rc] = '\0';
diff --git a/sys-utils/nsenter.c b/sys-utils/nsenter.c
index 8f7bac922..58130e932 100644
--- a/sys-utils/nsenter.c
+++ b/sys-utils/nsenter.c
@@ -365,7 +365,6 @@ int main(int argc, char *argv[])
 	uid_t uid = 0;
 	gid_t gid = 0;
 	int keepcaps = 0;
-	struct ul_env_list *envls;
 #ifdef HAVE_LIBSELINUX
 	bool selinux = 0;
 #endif
@@ -644,12 +643,15 @@ int main(int argc, char *argv[])
 
 	/* Pass environment variables of the target process to the spawned process */
 	if (env_fd >= 0) {
-		if ((envls = env_from_fd(env_fd)) == NULL)
+		struct ul_env_list *ls;
+
+		ls = env_from_fd(env_fd);
+		if (!ls && errno)
 			err(EXIT_FAILURE, _("failed to get environment variables"));
 		clearenv();
-		if (env_list_setenv(envls) < 0)
+		if (ls && env_list_setenv(ls) < 0)
 			err(EXIT_FAILURE, _("failed to set environment variables"));
-		env_list_free(envls);
+		env_list_free(ls);
 		close(env_fd);
 	}