ksw_get_config() exposes the configuration pointer as const.

Signed-off-by: Jinchao Wang <redacted>
---
 mm/kstackwatch/kernel.c      | 77 +++++++++++++++++++++++++++++++++++-
 mm/kstackwatch/kstackwatch.h |  3 ++
 2 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/mm/kstackwatch/kernel.c b/mm/kstackwatch/kernel.c
index 3b7009033dd4..4a06ddadd9c7 100644
--- a/mm/kstackwatch/kernel.c
+++ b/mm/kstackwatch/kernel.c

@@ -3,11 +3,15 @@

 #include <linux/kstrtox.h>
 #include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
 #include <linux/string.h>
+#include <linux/uaccess.h>

 #include "kstackwatch.h"

 static struct ksw_config *ksw_config;
+static atomic_t config_file_busy = ATOMIC_INIT(0);

 struct param_map {
        const char *name;       /* long name */

@@ -74,7 +78,7 @@ static int ksw_parse_param(struct ksw_config *config, const char *key,
  * - sp_offset  |so (u16) : offset from stack pointer at func_offset
  * - watch_len  |wl (u16) : watch length (1,2,4,8)
  */
-static int __maybe_unused ksw_parse_config(char *buf, struct ksw_config *config)
+static int ksw_parse_config(char *buf, struct ksw_config *config)
 {
        char *part, *key, *val;
        int ret;

@@ -109,18 +113,89 @@ static int __maybe_unused ksw_parse_config(char *buf, struct ksw_config *config)
        return 0;
 }

+static ssize_t kstackwatch_proc_write(struct file *file,
+                                     const char __user *buffer, size_t count,
+                                     loff_t *pos)
+{
+       char input[MAX_CONFIG_STR_LEN];
+       int ret;
+
+       if (count == 0 || count >= sizeof(input))
+               return -EINVAL;
+
+       if (copy_from_user(input, buffer, count))
+               return -EFAULT;
+
+       input[count] = '\0';
+       strim(input);
+
+       if (!strlen(input)) {
+               pr_info("config cleared\n");
+               return count;
+       }
+
+       ret = ksw_parse_config(input, ksw_config);
+       if (ret) {
+               pr_err("Failed to parse config %d\n", ret);
+               return ret;
+       }
+
+       return count;
+}
+
+static int kstackwatch_proc_show(struct seq_file *m, void *v)
+{
+       seq_printf(m, "%s\n", ksw_config->user_input);
+       return 0;
+}
+
+static int kstackwatch_proc_open(struct inode *inode, struct file *file)
+{
+       if (atomic_cmpxchg(&config_file_busy, 0, 1))
+               return -EBUSY;
+
+       return single_open(file, kstackwatch_proc_show, NULL);
+}
+
+static int kstackwatch_proc_release(struct inode *inode, struct file *file)
+{
+       atomic_set(&config_file_busy, 0);
+       return single_release(inode, file);
+}
+
+static const struct proc_ops kstackwatch_proc_ops = {
+       .proc_open = kstackwatch_proc_open,
+       .proc_read = seq_read,
+       .proc_write = kstackwatch_proc_write,
+       .proc_lseek = seq_lseek,
+       .proc_release = kstackwatch_proc_release,
+};
+
+const struct ksw_config *ksw_get_config(void)
+{
+       return ksw_config;
+}
 static int __init kstackwatch_init(void)
 {
        ksw_config = kzalloc(sizeof(*ksw_config), GFP_KERNEL);
        if (!ksw_config)
                return -ENOMEM;

+       if (!proc_create("kstackwatch", 0600, NULL, &kstackwatch_proc_ops)) {
+               pr_err("create proc kstackwatch fail");
+               kfree(ksw_config);
+               return -ENOMEM;
+       }
+
        pr_info("module loaded\n");
        return 0;
 }

 static void __exit kstackwatch_exit(void)
 {
+       remove_proc_entry("kstackwatch", NULL);
+       kfree(ksw_config->func_name);
+       kfree(ksw_config->user_input);
        kfree(ksw_config);

        pr_info("module unloaded\n");

diff --git a/mm/kstackwatch/kstackwatch.h b/mm/kstackwatch/kstackwatch.h
index a7bad207f863..983125d5cf18 100644
--- a/mm/kstackwatch/kstackwatch.h
+++ b/mm/kstackwatch/kstackwatch.h

@@ -29,4 +29,7 @@ struct ksw_config {
        char *user_input;
 };

+// singleton, only modified in kernel.c
+const struct ksw_config *ksw_get_config(void);
+
 #endif /* _KSTACKWATCH_H */
--

2.43.0

--
You received this message because you are subscribed to the Google Groups "kasan-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
To view this discussion visit https://groups.google.com/d/msgid/kasan-dev/20250924115124.194940-7-wangjinchao600%40gmail.com.