diff options
| -rw-r--r-- | lib/libthr/thread/thr_fork.c | 13 | ||||
| -rw-r--r-- | lib/libthr/thread/thr_rtld.c | 21 | ||||
| -rw-r--r-- | libexec/rtld-elf/rtld_lock.c | 16 |
3 files changed, 45 insertions, 5 deletions
diff --git a/lib/libthr/thread/thr_fork.c b/lib/libthr/thread/thr_fork.c index c26541e..fc87688 100644 --- a/lib/libthr/thread/thr_fork.c +++ b/lib/libthr/thread/thr_fork.c @@ -57,6 +57,7 @@ * */ +#include <sys/syscall.h> #include "namespace.h" #include <errno.h> #include <link.h> @@ -174,8 +175,15 @@ _fork(void) was_threaded = 0; } - /* Fork a new process: */ - if ((ret = __sys_fork()) == 0) { + /* + * Fork a new process. + * There is no easy way to pre-resolve the __sys_fork symbol + * without performing the fork. Use the syscall(2) + * indirection, the syscall symbol is resolved in + * _thr_rtld_init() with side-effect free call. + */ + ret = syscall(SYS_fork); + if (ret == 0) { /* Child process */ errsave = errno; curthread->cancel_pending = 0; @@ -250,6 +258,5 @@ _fork(void) } errno = errsave; - /* Return the process ID: */ return (ret); } diff --git a/lib/libthr/thread/thr_rtld.c b/lib/libthr/thread/thr_rtld.c index fd379d6..5d89988 100644 --- a/lib/libthr/thread/thr_rtld.c +++ b/lib/libthr/thread/thr_rtld.c @@ -32,10 +32,12 @@ */ #include <sys/cdefs.h> #include <sys/mman.h> +#include <sys/syscall.h> #include <link.h> #include <stdlib.h> #include <string.h> +#include "libc_private.h" #include "rtld_lock.h" #include "thr_private.h" @@ -207,7 +209,24 @@ _thr_rtld_init(void) li.thread_set_flag = _thr_rtld_set_flag; li.thread_clr_flag = _thr_rtld_clr_flag; li.at_fork = NULL; - + + /* + * Preresolve the symbols needed for the fork interposer. We + * call _rtld_atfork_pre() and _rtld_atfork_post() with NULL + * argument to indicate that no actual locking inside the + * functions should happen. Neither rtld compat locks nor + * libthr rtld locks cannot work there: + * - compat locks do not handle the case of two locks taken + * in write mode (the signal mask for the thread is corrupted); + * - libthr locks would work, but locked rtld_bind_lock prevents + * symbol resolution for _rtld_atfork_post. + */ + _rtld_atfork_pre(NULL); + _rtld_atfork_post(NULL); + _malloc_prefork(); + _malloc_postfork(); + syscall(SYS_getpid); + /* mask signals, also force to resolve __sys_sigprocmask PLT */ _thr_signal_block(curthread); _rtld_thread_init(&li); diff --git a/libexec/rtld-elf/rtld_lock.c b/libexec/rtld-elf/rtld_lock.c index d1563e5..ea16c4d 100644 --- a/libexec/rtld-elf/rtld_lock.c +++ b/libexec/rtld-elf/rtld_lock.c @@ -365,8 +365,19 @@ _rtld_atfork_pre(int *locks) { RtldLockState ls[2]; + if (locks == NULL) + return; + + /* + * Warning: this does not work with the rtld compat locks + * above, since the thread signal mask is corrupted (set to + * all signals blocked) if two locks are taken in write mode. + * The caller of the _rtld_atfork_pre() must provide the + * working implementation of the locks, and libthr locks are + * fine. + */ wlock_acquire(rtld_phdr_lock, &ls[0]); - rlock_acquire(rtld_bind_lock, &ls[1]); + wlock_acquire(rtld_bind_lock, &ls[1]); /* XXXKIB: I am really sorry for this. */ locks[0] = ls[1].lockstate; @@ -378,6 +389,9 @@ _rtld_atfork_post(int *locks) { RtldLockState ls[2]; + if (locks == NULL) + return; + bzero(ls, sizeof(ls)); ls[0].lockstate = locks[2]; ls[1].lockstate = locks[0]; |
