@@ -208,7 +208,7 @@ static inline abi_long do_freebsd_fork(void *cpu_env)
*/
set_second_rval(cpu_env, child_flag);
- fork_end(child_flag);
+ fork_end(ret);
return ret;
}
@@ -252,7 +252,7 @@ static inline abi_long do_freebsd_rfork(void *cpu_env, abi_long flags)
* value: 0 for parent process, 1 for child process.
*/
set_second_rval(cpu_env, child_flag);
- fork_end(child_flag);
+ fork_end(ret);
return ret;
@@ -285,7 +285,7 @@ static inline abi_long do_freebsd_pdfork(void *cpu_env, abi_ulong target_fdp,
* value: 0 for parent process, 1 for child process.
*/
set_second_rval(cpu_env, child_flag);
- fork_end(child_flag);
+ fork_end(ret);
return ret;
}
@@ -106,10 +106,13 @@ void fork_start(void)
start_exclusive();
cpu_list_lock();
mmap_fork_start();
+ gdbserver_fork_start();
}
-void fork_end(int child)
+void fork_end(abi_long pid)
{
+ int child = pid == 0;
+
if (child) {
CPUState *cpu, *next_cpu;
/*
@@ -127,10 +130,11 @@ void fork_end(int child)
* state, so we don't need to end_exclusive() here.
*/
qemu_init_cpu_list();
- gdbserver_fork(thread_cpu);
+ gdbserver_fork_end(pid);
} else {
mmap_fork_end(child);
cpu_list_unlock();
+ gdbserver_fork_end(pid);
end_exclusive();
}
}
@@ -180,7 +180,7 @@ void cpu_loop(CPUArchState *env);
char *target_strerror(int err);
int get_osversion(void);
void fork_start(void);
-void fork_end(int child);
+void fork_end(abi_long pid);
#include "qemu/log.h"
@@ -356,16 +356,29 @@ int gdbserver_start(const char *port_or_path)
return -1;
}
+void gdbserver_fork_start(void)
+{
+}
+
+static void disable_gdbstub(void)
+{
+ CPUState *cpu;
+
+ close(gdbserver_user_state.fd);
+ gdbserver_user_state.fd = -1;
+ CPU_FOREACH(cpu) {
+ cpu_breakpoint_remove_all(cpu, BP_GDB);
+ /* no cpu_watchpoint_remove_all for user-mode */
+ }
+}
+
/* Disable gdb stub for child processes. */
-void gdbserver_fork(CPUState *cpu)
+void gdbserver_fork_end(pid_t pid)
{
- if (!gdbserver_state.init || gdbserver_user_state.fd < 0) {
+ if (pid != 0 || !gdbserver_state.init || gdbserver_user_state.fd < 0) {
return;
}
- close(gdbserver_user_state.fd);
- gdbserver_user_state.fd = -1;
- cpu_breakpoint_remove_all(cpu, BP_GDB);
- /* no cpu_watchpoint_remove_all for user-mode */
+ disable_gdbstub();
}
/*
@@ -46,10 +46,15 @@ static inline int gdb_handlesig(CPUState *cpu, int sig)
void gdb_signalled(CPUArchState *as, int sig);
/**
- * gdbserver_fork() - disable gdb stub for child processes.
- * @cs: CPU
+ * gdbserver_fork_start() - inform gdb of the upcoming fork()
+ */
+void gdbserver_fork_start(void);
+
+/**
+ * gdbserver_fork_end() - disable gdb stub for child processes.
+ * @pid: 0 if in child process, -1 if fork failed, child process pid otherwise
*/
-void gdbserver_fork(CPUState *cs);
+void gdbserver_fork_end(pid_t pid);
/**
* gdb_syscall_entry() - inform gdb of syscall entry and yield control to it
@@ -144,10 +144,13 @@ void fork_start(void)
mmap_fork_start();
cpu_list_lock();
qemu_plugin_user_prefork_lock();
+ gdbserver_fork_start();
}
-void fork_end(int child)
+void fork_end(abi_long pid)
{
+ int child = pid == 0;
+
qemu_plugin_user_postfork(child);
mmap_fork_end(child);
if (child) {
@@ -160,10 +163,11 @@ void fork_end(int child)
}
}
qemu_init_cpu_list();
- gdbserver_fork(thread_cpu);
+ ((TaskState *)thread_cpu->opaque)->ts_tid = (pid_t)syscall(SYS_gettid);
} else {
cpu_list_unlock();
}
+ gdbserver_fork_end(pid);
/*
* qemu_init_cpu_list() reinitialized the child exclusive state, but we
* also need to keep current_cpu consistent, so call end_exclusive() for
@@ -6669,7 +6669,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
if (ret == 0) {
/* Child Process. */
cpu_clone_regs_child(env, newsp, flags);
- fork_end(1);
+ fork_end(ret);
/* There is a race condition here. The parent process could
theoretically read the TID in the child process before the child
tid is set. This would require using either ptrace
@@ -6701,7 +6701,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp,
#endif
put_user_u32(pid_fd, parent_tidptr);
}
- fork_end(0);
+ fork_end(ret);
}
g_assert(!cpu_in_exclusive_context(cpu));
}
@@ -71,7 +71,7 @@ const char *target_strerror(int err);
int get_osversion(void);
void init_qemu_uname_release(void);
void fork_start(void);
-void fork_end(int child);
+void fork_end(abi_long pid);
/**
* probe_guest_base:
Prepare for implementing follow-fork-mode child: * Introduce gdbserver_fork_start(), which for now is a no-op. * Rename gdbserver_fork() to gdbserver_fork_end(), call it in both parent and child processes, and pass the fork()'s return value to it. * Factor out disable_gdbstub(). * Update ts_tid in the forked child. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- bsd-user/freebsd/os-proc.h | 6 +++--- bsd-user/main.c | 8 ++++++-- bsd-user/qemu.h | 2 +- gdbstub/user.c | 25 +++++++++++++++++++------ include/gdbstub/user.h | 11 ++++++++--- linux-user/main.c | 8 ++++++-- linux-user/syscall.c | 4 ++-- linux-user/user-internals.h | 2 +- 8 files changed, 46 insertions(+), 20 deletions(-)