When the -seed option is given, call qemu_guest_random_seed_main, putting the subsystem into deterministic mode. Pass derived seeds to each cpu created during clone; which is a no-op unless the subsystem is in deterministic mode.
Reviewed-by: Laurent Vivier <lviv...@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com> Signed-off-by: Richard Henderson <richard.hender...@linaro.org> --- v5: Retain srand() until last user goes away. --- linux-user/main.c | 30 +++++++++++++++++++----------- linux-user/syscall.c | 3 +++ 2 files changed, 22 insertions(+), 11 deletions(-) diff --git a/linux-user/main.c b/linux-user/main.c index 3d2230320b..7e704845c0 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -34,6 +34,7 @@ #include "tcg.h" #include "qemu/timer.h" #include "qemu/envlist.h" +#include "qemu/guest-random.h" #include "elf.h" #include "trace/control.h" #include "target_elf.h" @@ -48,6 +49,7 @@ static int gdbstub_port; static envlist_t *envlist; static const char *cpu_model; static const char *cpu_type; +static const char *seed_optarg; unsigned long mmap_min_addr; unsigned long guest_base; int have_guest_base; @@ -290,15 +292,9 @@ static void handle_arg_pagesize(const char *arg) } } -static void handle_arg_randseed(const char *arg) +static void handle_arg_seed(const char *arg) { - unsigned long long seed; - - if (parse_uint_full(arg, &seed, 0) != 0 || seed > UINT_MAX) { - fprintf(stderr, "Invalid seed number: %s\n", arg); - exit(EXIT_FAILURE); - } - srand(seed); + seed_optarg = arg; } static void handle_arg_gdb(const char *arg) @@ -433,7 +429,7 @@ static const struct qemu_argument arg_table[] = { "", "run in singlestep mode"}, {"strace", "QEMU_STRACE", false, handle_arg_strace, "", "log system calls"}, - {"seed", "QEMU_RAND_SEED", true, handle_arg_randseed, + {"seed", "QEMU_RAND_SEED", true, handle_arg_seed, "", "Seed for pseudo-random number generator"}, {"trace", "QEMU_TRACE", true, handle_arg_trace, "", "[[enable=]<pattern>][,events=<file>][,file=<file>]"}, @@ -689,8 +685,20 @@ int main(int argc, char **argv, char **envp) do_strace = 1; } - if (getenv("QEMU_RAND_SEED")) { - handle_arg_randseed(getenv("QEMU_RAND_SEED")); + if (seed_optarg == NULL) { + seed_optarg = getenv("QEMU_RAND_SEED"); + } + if (seed_optarg != NULL) { + unsigned long long seed; + + /* This will go away with the last user of rand(). */ + if (parse_uint_full(seed_optarg, &seed, 0) != 0) { + fprintf(stderr, "Invalid seed number: %s\n", seed_optarg); + exit(EXIT_FAILURE); + } + srand(seed); + + qemu_guest_random_seed_main(seed_optarg, &error_fatal); } target_environ = envlist_to_environ(envlist, NULL); diff --git a/linux-user/syscall.c b/linux-user/syscall.c index f5ff6f5dc8..96f20886ce 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -107,6 +107,7 @@ #include "uname.h" #include "qemu.h" +#include "qemu/guest-random.h" #include "fd-trans.h" #ifndef CLONE_IO @@ -5482,6 +5483,7 @@ static void *clone_func(void *arg) put_user_u32(info->tid, info->child_tidptr); if (info->parent_tidptr) put_user_u32(info->tid, info->parent_tidptr); + qemu_guest_random_seed_thread_part2(cpu->random_seed); /* Enable signals. */ sigprocmask(SIG_SETMASK, &info->sigmask, NULL); /* Signal to the parent that we're ready. */ @@ -5568,6 +5570,7 @@ static int do_fork(CPUArchState *env, unsigned int flags, abi_ulong newsp, initializing, so temporarily block all signals. */ sigfillset(&sigmask); sigprocmask(SIG_BLOCK, &sigmask, &info.sigmask); + cpu->random_seed = qemu_guest_random_seed_thread_part1(); /* If this is our first additional thread, we need to ensure we * generate code for parallel execution and flush old translations. -- 2.17.1