git: e2279d5ba9a9 - main - tcpdrop: improve handling of -C and -S

The branch main has been updated by tuexen:

URL: https://cgit.FreeBSD.org/src/commit/?id=e2279d5ba9a91407239cba4bed80abff73b15798

commit e2279d5ba9a91407239cba4bed80abff73b15798
Author:     Michael Tuexen <tuexen@FreeBSD.org>
AuthorDate: 2026-10-01 19:09:11 +0000
Commit:     Michael Tuexen <tuexen@FreeBSD.org>
CommitDate: 2026-10-01 19:14:11 +0000

    tcpdrop: improve handling of -C and -S
    
    Handle empty strings for -Cand -S correctly.
    
    Reported by:            maxim
    Reviewed by:            maxim
    MFC after:              1 week
    MFC to:                 stable/14
    MFC to:                 stable/15
    Sponsored by:           Netflix, Inc.
    Differential Revision:  https://reviews.freebsd.org/D60210
---
 usr.sbin/tcpdrop/tcpdrop.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/usr.sbin/tcpdrop/tcpdrop.c b/usr.sbin/tcpdrop/tcpdrop.c
index 6f6b94789df1..00404cb98794 100644
--- a/usr.sbin/tcpdrop/tcpdrop.c
+++ b/usr.sbin/tcpdrop/tcpdrop.c
@@ -63,16 +63,16 @@ static void usage(void) __dead2;
 int
 main(int argc, char *argv[])
 {
-	char stack[TCP_FUNCTION_NAME_LEN_MAX];
-	char ca_name[TCP_CA_NAME_MAX];
-	char *lport, *fport;
+	char stack_buf[TCP_FUNCTION_NAME_LEN_MAX];
+	char ca_name_buf[TCP_CA_NAME_MAX];
+	char *stack, *ca_name, *lport, *fport;
 	bool dropall, dropspecific;
 	int ch, state;
 
 	dropall = false;
 	dropspecific = false;
-	ca_name[0] = '\0';
-	stack[0] = '\0';
+	ca_name = NULL;
+	stack = NULL;
 	state = -1;
 
 	while ((ch = getopt(argc, argv, "aC:lS:s:")) != -1) {
@@ -82,14 +82,16 @@ main(int argc, char *argv[])
 			break;
 		case 'C':
 			dropspecific = true;
-			strlcpy(ca_name, optarg, sizeof(ca_name));
+			strlcpy(ca_name_buf, optarg, sizeof(ca_name_buf));
+			ca_name = ca_name_buf;
 			break;
 		case 'l':
 			tcpdrop_list_commands = true;
 			break;
 		case 'S':
 			dropspecific = true;
-			strlcpy(stack, optarg, sizeof(stack));
+			strlcpy(stack_buf, optarg, sizeof(stack_buf));
+			stack = stack_buf;
 			break;
 		case 's':
 			dropspecific = true;
@@ -266,12 +268,12 @@ tcpdropall(const char *ca_name, const char *stack, int state)
 		 * If requested, skip sockets not having the requested
 		 * congestion control algorithm.
 		 */
-		if (ca_name[0] != '\0' &&
+		if (ca_name != NULL &&
 		    strncmp(xtp->xt_cc, ca_name, TCP_CA_NAME_MAX))
 			continue;
 
 		/* If requested, skip sockets not having the requested stack. */
-		if (stack[0] != '\0' &&
+		if (stack != NULL &&
 		    strncmp(xtp->xt_stack, stack, TCP_FUNCTION_NAME_LEN_MAX))
 			continue;