From cad19d531164a4a0946848043e74b4e78e677886 Mon Sep 17 00:00:00 2001
From: seantywork <seantywork@gmail.com>
Date: Fri, 21 Nov 2025 03:36:31 +0000
Subject: [PATCH] kproc md

---
 kproc/2025-1121.xyz.md | 119 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 kproc/2025-1121.xyz.md

diff --git a/kproc/2025-1121.xyz.md b/kproc/2025-1121.xyz.md
new file mode 100644
index 0000000..29f1dd6
--- /dev/null
+++ b/kproc/2025-1121.xyz.md
@@ -0,0 +1,119 @@
+
+
+# find out context 
+
+```c
+static void show_proc_context(char* buf){
+    unsigned int uid;
+    if(likely(in_task())){
+        uid = from_kuid(&init_user_ns, current_uid());
+        snprintf(buf, KPROC_BUFF_LEN, "kproc: ctx: process: uid: %u: pid: %d", uid, task_pid_nr(current));
+    } else {
+        snprintf(buf, KPROC_BUFF_LEN, "kproc: ctx: interrupt");
+    }
+}
+
+```
+
+# kernel syscall handling
+
+```c
+static ssize_t device_read(struct file *filp, char *buffer, size_t len, loff_t *offset){
+    char tmp_msg_buffer[KPROC_BUFF_LEN] = {0};
+    show_proc_context(tmp_msg_buffer);
+    ssize_t n = copy_to_user(buffer, tmp_msg_buffer, KPROC_BUFF_LEN);
+    (*offset) += KPROC_BUFF_LEN;
+    return KPROC_BUFF_LEN - n;
+}
+
+```
+
+# kernel interrupt handling
+
+```c
+
+#define IRQ_1 1
+#define IRQ_1_DEV "keyboard"
+#define IRQ_1_ID "0001"
+
+// ...
+
+char tmp_msg_buffer[KPROC_BUFF_LEN] = {0};
+
+static irq_handler_t irq_1_handler(unsigned int irq, void* dev_id, struct pt_regs *regs){
+    show_proc_context(tmp_msg_buffer);
+    printk("kproc: isr: %s\n", tmp_msg_buffer);
+    memset(tmp_msg_buffer, 0, KPROC_BUFF_LEN);
+    return (irq_handler_t)IRQ_HANDLED;
+}
+```
+
+# insmod kproc.ko
+```shell
+[Nov21 03:22] kproc: hello
+```
+
+# ./user/user.out
+
+```shell
+devices:
+Character devices:
+  1 mem
+  4 /dev/vc/0
+  4 tty
+  4 ttyS
+  5 /dev/tty
+  5 /dev/console
+  5 /dev/ptmx
+  5 ttyprintk
+  7 vcs
+ 10 misc
+ ...
+
+```
+
+```shell
+239 kproc_f
+target major: 239
+main: kproc: ctx: process: uid: 0: pid: 109635
+thread: kproc: ctx: process: uid: 0: pid: 109636
+main: kproc: ctx: process: uid: 0: pid: 109635
+thread: kproc: ctx: process: uid: 0: pid: 109636
+main: kproc: ctx: process: uid: 0: pid: 109635
+thread: kproc: ctx: process: uid: 0: pid: 109636
+main: kproc: ctx: process: uid: 0: pid: 109635
+thread: kproc: ctx: process: uid: 0: pid: 109636
+main: kproc: ctx: process: uid: 0: pid: 109635
+thread: kproc: ctx: process: uid: 0: pid: 109636
+main: kproc: ctx: process: uid: 0: pid: 109635
+thread: kproc: ctx: process: uid: 0: pid: 109636
+^CSIG: 2
+```
+
+```shell
+[Nov21 03:23] file opened: 1
+[  +5.292114] file closed: 0
+```
+
+# interrupt on another terminal
+
+```shell
+[Nov21 03:25] kproc: isr: kproc: ctx: interrupt
+[  +0.000136] kproc: isr: kproc: ctx: interrupt
+[  +0.184034] kproc: isr: kproc: ctx: interrupt
+[  +0.000194] kproc: isr: kproc: ctx: interrupt
+[  +1.263342] kproc: isr: kproc: ctx: interrupt
+[  +0.000102] kproc: isr: kproc: ctx: interrupt
+[  +0.143710] kproc: isr: kproc: ctx: interrupt
+[  +0.000103] kproc: isr: kproc: ctx: interrupt
+[  +9.776542] kproc: isr: kproc: ctx: interrupt
+[  +0.151752] kproc: isr: kproc: ctx: interrupt
+[  +0.151249] kproc: isr: kproc: ctx: interrupt
+
+```
+
+# rmmod 
+
+```shell
+[ +30.320705] kproc: bye
+```
\ No newline at end of file
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