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authorMagnus Reftel <reftel@spotify.com>2014-10-14 17:18:17 +0200
committerRiku Voipio <riku.voipio@linaro.org>2014-11-03 11:03:34 +0200
commitc5e4a5a95e6de549fdf131c77c0f8d25b6ee7f30 (patch)
tree8e60a241f11aa81e134dce384c5aa40715dcd2da /linux-user
parent0a2923f8488498000eec54871456aa64a4391da4 (diff)
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linux-user: Let user specify random seed
This patch introduces the -seed command line option and the QEMU_RAND_SEED environment variable for setting the random seed, which is used for the AT_RANDOM ELF aux entry. Signed-off-by: Magnus Reftel <reftel@spotify.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/elfload.c1
-rw-r--r--linux-user/main.c19
2 files changed, 19 insertions, 1 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 1c04fcf..f2e2197 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1539,7 +1539,6 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
* Generate 16 random bytes for userspace PRNG seeding (not
* cryptically secure but it's not the aim of QEMU).
*/
- srand((unsigned int) time(NULL));
for (i = 0; i < 16; i++) {
k_rand_bytes[i] = rand();
}
diff --git a/linux-user/main.c b/linux-user/main.c
index 483eb3f..5887022 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3546,6 +3546,17 @@ static void handle_arg_pagesize(const char *arg)
}
}
+static void handle_arg_randseed(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(1);
+ }
+ srand(seed);
+}
+
static void handle_arg_gdb(const char *arg)
{
gdbstub_port = atoi(arg);
@@ -3674,6 +3685,8 @@ 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 for pseudo-random number generator"},
{"version", "QEMU_VERSION", false, handle_arg_version,
"", "display version information and exit"},
{NULL, NULL, false, NULL, NULL, NULL}
@@ -3856,6 +3869,8 @@ int main(int argc, char **argv, char **envp)
cpudef_setup(); /* parse cpu definitions in target config file (TBD) */
#endif
+ srand(time(NULL));
+
optind = parse_args(argc, argv);
/* Zero out regs */
@@ -3926,6 +3941,10 @@ int main(int argc, char **argv, char **envp)
do_strace = 1;
}
+ if (getenv("QEMU_RAND_SEED")) {
+ handle_arg_randseed(getenv("QEMU_RAND_SEED"));
+ }
+
target_environ = envlist_to_environ(envlist, NULL);
envlist_free(envlist);