From d79358f91cc4340b71b7d4e83fa432e8c98a7b22 Mon Sep 17 00:00:00 2001
From: Peter Gerwinski <peter.gerwinski@hs-bochum.de>
Date: Sun, 31 May 2015 23:29:44 +0200
Subject: [PATCH] Notizen zu den Lehrveranstaltungen vom 11. und 18. Mai 2015
---
slides/bs-20150511.txt | 58 ++++++++++++++++++++++++++++++++++++++++++
slides/bs-20150518.txt | 13 ++++++++++
2 files changed, 71 insertions(+)
create mode 100644 slides/bs-20150511.txt
create mode 100644 slides/bs-20150518.txt
diff --git a/slides/bs-20150511.txt b/slides/bs-20150511.txt
new file mode 100644
index 0000000..33cd162
--- /dev/null
+++ b/slides/bs-20150511.txt
@@ -0,0 +1,58 @@
+Verzeichnis: Linux-Quelltext
+$ find . -name "*syscall*"
+$ vi -R ./arch/x86/kernel/syscall_64.c
+--> Definition von "sys_call_table" über wiederholte Includes
+$ find . -name syscalls_64.h
+$ vi -R ./arch/sh/include/asm/syscalls_64.h
+$ vi -R ./arch/x86/um/shared/sysdep/syscalls_64.h
+--> beides nicht sehr erhellend
+$ locate syscalls_64.h
+$ vi -R /usr/src/linux-headers-3.16.0-4-amd64/arch/x86/include/generated/asm/syscalls_64.h
+$ grep -R syscalls_64\.h *
+$ vi -R arch/x86/syscalls/Makefile
+$ find . -name syscall_64.tbl
+$ vi -R ./arch/x86/syscalls/syscall_64.tbl
+--> :-)
+$ vi -R ./arch/x86/kernel/syscall_64.c
+--> Die 2. Spalte ("sym") bezeichnet den Funktionsnamen.
+ - Wie findet der "syscall"-Befehl die Tabelle?
+ - Wo wird die Funktion deklariert?
+$ grep -R sys_call_table arch/x86/*
+$ vi -R arch/x86/kernel/entry_64.S
+--> :-)
+$ grep -wr write *
+--> :-(
+# DuckDuckGo --> http://www.usmanacademy.com/2012/07/linux-system-call-implementation.html
+$ find . -name "*write*"
+$ vi -R ./fs/read_write.c
+--> SYSCALL_DEFINE3(write, ...)
+ struct fd
+ vfs_write()
+$ vi -R include/linux/file.h
+--> struct file *file;
+$ grep -r "struct file {" $(find . -name "*.h")
+$ vi -R ./include/linux/fs.h
+--> const struct file_operations *f_op;
+--> ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *);
+--> :-)
+$ vi -R ./fs/read_write.c
+--> vfs_write():
+ if (file->f_op->write)
+ ret = file->f_op->write(file, buf, count, pos);
+
+Beim Öffnen der Datei werden die file_operations in der struct file hinterlegt.
+
+Skript, 11.05.2015, 13:58:25
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ - \usepackage{hyperref}
+ - Daemon schreibt in log-Datei: In welche?
+
+sprintf, 11.05.2015, 14:49:56
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ char buf[42];
+ sprintf (buf, "%s", "Hello");
+ sprintf (buf + 5, "%s\n", ", world!");
+
+oder besser:
+
+ sprintf (buf + strlen (buf), "%s\n", ", world!");
diff --git a/slides/bs-20150518.txt b/slides/bs-20150518.txt
new file mode 100644
index 0000000..55f30dd
--- /dev/null
+++ b/slides/bs-20150518.txt
@@ -0,0 +1,13 @@
+Merlin Klaßen, 18.05.2015, 11:38:37
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+device_write()
+
+cdev_init()
+cdev_add()
+device_create()
+
+device_destroy()
+class_destroy()
+cdev_del()
+
+--> Der udev-deamon kümmert sich um das Anlegen und Entfernen der char-Device.
--
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