linux-kernel - [PATCH 82/99] fbdev/tgafb: Duplicate video-mode option string

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Message-Id: <20230306160016.4459-83-tzimmermann@suse.de>
Date:   Mon,  6 Mar 2023 16:59:59 +0100
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     deller@....de, paulus@...ba.org, benh@...nel.crashing.org,
        linux@...linux.org.uk, pjones@...hat.com, timur@...nel.org,
        adaplas@...il.com, s.hauer@...gutronix.de, shawnguo@...nel.org,
        mbroemme@...mpq.org, thomas@...ischhofer.net,
        James.Bottomley@...senPartnership.com, spock@...too.org,
        sudipm.mukherjee@...il.com, teddy.wang@...iconmotion.com,
        geert+renesas@...der.be, corbet@....net
Cc:     linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: [PATCH 82/99] fbdev/tgafb: Duplicate video-mode option string

Assume that the driver does not own the option string or its substrings
and hence duplicate the option string for the video mode. The driver only
parses the option string once as part of module initialization, so use
a static buffer to store the duplicated mode option. Linux automatically
frees the memory upon releasing the module.

Done in preparation of switching the driver to struct option_iter and
constifying the option string.

Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
---
 drivers/video/fbdev/tgafb.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/tgafb.c b/drivers/video/fbdev/tgafb.c
index 14d37c49633c..a412fdddfd8c 100644
--- a/drivers/video/fbdev/tgafb.c
+++ b/drivers/video/fbdev/tgafb.c
@@ -1579,9 +1579,21 @@ static int tgafb_setup(char *arg)
 		while ((this_opt = strsep(&arg, ","))) {
 			if (!*this_opt)
 				continue;
-			if (!strncmp(this_opt, "mode:", 5))
-				mode_option = this_opt+5;
-			else
+			if (!strncmp(this_opt, "mode:", 5)) {
+				static char mode_option_buf[256];
+				int ret;
+
+				ret = snprintf(mode_option_buf, sizeof(mode_option_buf), "%s",
+					       this_opt + 5);
+				if (WARN(ret < 0,
+					 "tgafb: ignoring invalid option, ret=%d\n",
+					 ret))
+					continue;
+				if (WARN(ret >= sizeof(mode_option_buf),
+					 "tgafb: option too long\n"))
+					continue;
+				mode_option = mode_option_buf;
+			} else
 				printk(KERN_ERR
 				       "tgafb: unknown parameter %s\n",
 				       this_opt);
-- 
2.39.2