diff options
Diffstat (limited to 'stdlib/exit.c')
| -rw-r--r-- | stdlib/exit.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/stdlib/exit.c b/stdlib/exit.c index c0b6d666c7..b74f1825f0 100644 --- a/stdlib/exit.c +++ b/stdlib/exit.c @@ -19,11 +19,16 @@ #include <stdlib.h> #include <unistd.h> #include <sysdep.h> +#include <libc-lock.h> #include "exit.h" #include "set-hooks.h" DEFINE_HOOK (__libc_atexit, (void)) +/* Initialize the flag that indicates exit function processing + is complete. See concurrency notes in stdlib/exit.h where + __exit_funcs_lock is declared. */ +bool __exit_funcs_done = false; /* Call all functions registered with `atexit' and `on_exit', in the reverse of the order in which they were registered @@ -44,14 +49,32 @@ __run_exit_handlers (int status, struct exit_function_list **listp, the functions registered with `atexit' and `on_exit'. We call everyone on the list and use the status value in the last exit (). */ - while (*listp != NULL) + while (true) { - struct exit_function_list *cur = *listp; + struct exit_function_list *cur; + + __libc_lock_lock (__exit_funcs_lock); + + restart: + cur = *listp; + + if (cur == NULL) + { + /* Exit processing complete. We will not allow any more + atexit/on_exit registrations. */ + __exit_funcs_done = true; + __libc_lock_unlock (__exit_funcs_lock); + break; + } while (cur->idx > 0) { const struct exit_function *const f = &cur->fns[--cur->idx]; + const uint64_t new_exitfn_called = __new_exitfn_called; + + /* Unlock the list while we call a foreign function. */ + __libc_lock_unlock (__exit_funcs_lock); switch (f->flavor) { void (*atfct) (void); @@ -83,6 +106,13 @@ __run_exit_handlers (int status, struct exit_function_list **listp, cxafct (f->func.cxa.arg, status); break; } + /* Re-lock again before looking at global state. */ + __libc_lock_lock (__exit_funcs_lock); + + if (__glibc_unlikely (new_exitfn_called != __new_exitfn_called)) + /* The last exit function, or another thread, has registered + more exit functions. Start the loop over. */ + goto restart; } *listp = cur->next; @@ -90,6 +120,8 @@ __run_exit_handlers (int status, struct exit_function_list **listp, /* Don't free the last element in the chain, this is the statically allocate element. */ free (cur); + + __libc_lock_unlock (__exit_funcs_lock); } if (run_list_atexit) |