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linux-user: Initialize pseudo-random seeds for all guest cpus

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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 <lvivier@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2019-03-14 13:10:53 -07:00
parent 9c09a2518e
commit 5ebdd77494
2 changed files with 22 additions and 11 deletions
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30
linux-user/main.c
View File

@ -34,6 +34,7 @@
#include "tcg.h" #include "tcg.h"
#include "qemu/timer.h" #include "qemu/timer.h"
#include "qemu/envlist.h" #include "qemu/envlist.h"
#include "qemu/guest-random.h"
#include "elf.h" #include "elf.h"
#include "trace/control.h" #include "trace/control.h"
#include "target_elf.h" #include "target_elf.h"
@ -48,6 +49,7 @@ static int gdbstub_port;
static envlist_t *envlist; static envlist_t *envlist;
static const char *cpu_model; static const char *cpu_model;
static const char *cpu_type; static const char *cpu_type;
static const char *seed_optarg;
unsigned long mmap_min_addr; unsigned long mmap_min_addr;
unsigned long guest_base; unsigned long guest_base;
int have_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; seed_optarg = arg;
if (parse_uint_full(arg, &seed, 0) != 0 || seed > UINT_MAX) {
fprintf(stderr, "Invalid seed number: %s\n", arg);
exit(EXIT_FAILURE);
}
srand(seed);
} }
static void handle_arg_gdb(const char *arg) static void handle_arg_gdb(const char *arg)
@ -433,7 +429,7 @@ static const struct qemu_argument arg_table[] = {
"", "run in singlestep mode"}, "", "run in singlestep mode"},
{"strace", "QEMU_STRACE", false, handle_arg_strace, {"strace", "QEMU_STRACE", false, handle_arg_strace,
"", "log system calls"}, "", "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"}, "", "Seed for pseudo-random number generator"},
{"trace", "QEMU_TRACE", true, handle_arg_trace, {"trace", "QEMU_TRACE", true, handle_arg_trace,
"", "[[enable=]<pattern>][,events=<file>][,file=<file>]"}, "", "[[enable=]<pattern>][,events=<file>][,file=<file>]"},
@ -689,8 +685,20 @@ int main(int argc, char **argv, char **envp)
do_strace = 1; do_strace = 1;
} }
if (getenv("QEMU_RAND_SEED")) { if (seed_optarg == NULL) {
handle_arg_randseed(getenv("QEMU_RAND_SEED")); 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); target_environ = envlist_to_environ(envlist, NULL);

3
linux-user/syscall.c
View File

@ -107,6 +107,7 @@
#include "uname.h" #include "uname.h"
#include "qemu.h" #include "qemu.h"
#include "qemu/guest-random.h"
#include "fd-trans.h" #include "fd-trans.h"
#ifndef CLONE_IO #ifndef CLONE_IO
@ -5482,6 +5483,7 @@ static void *clone_func(void *arg)
put_user_u32(info->tid, info->child_tidptr); put_user_u32(info->tid, info->child_tidptr);
if (info->parent_tidptr) if (info->parent_tidptr)
put_user_u32(info->tid, info->parent_tidptr); put_user_u32(info->tid, info->parent_tidptr);
qemu_guest_random_seed_thread_part2(cpu->random_seed);
/* Enable signals. */ /* Enable signals. */
sigprocmask(SIG_SETMASK, &info->sigmask, NULL); sigprocmask(SIG_SETMASK, &info->sigmask, NULL);
/* Signal to the parent that we're ready. */ /* 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. */ initializing, so temporarily block all signals. */
sigfillset(&sigmask); sigfillset(&sigmask);
sigprocmask(SIG_BLOCK, &sigmask, &info.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 /* If this is our first additional thread, we need to ensure we
* generate code for parallel execution and flush old translations. * generate code for parallel execution and flush old translations.