October 2017
Intermediate to advanced
354 pages
9h 28m
English
Content preview from Mastering Linux Kernel Development
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do_fork() and copy_process()
All of the process/thread creation calls discussed so far invoke different system calls (except create_thread) to step into kernel mode. All of those system calls in turn converge into the common kernel function _do_fork(), which is invoked with distinct CLONE_* flags. do_fork() internally falls back on copy_process() to complete the task. The following figure sums up the call sequence for process creation:
/* kernel/fork.c *//* * Create a kernel thread. */
pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags){ return _do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn, (unsigned long)arg, NULL, NULL, 0);}/* sys_fork: create a child process by duplicating caller */SYSCALL_DEFINE0(fork)Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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