On Sun, Sep 9, 2018 at 2:47 PM Hongxu Jia <hongxu.jia@windriver.com> wrote:
The lack of random_r in musl:
[snip]
|main.c:1393:7: warning: implicit declaration of function 'random_r';
did you mean 'random'? [-Wimplicit-function-declaration]
|  rv = random_r(&rand_data, &val);
|       ^~~~~~~~
|       random
|main.c:1408:30: error: invalid application of 'sizeof' to incomplete
type 'struct random_data'
|  memset(&rand_data, 0, sizeof(rand_data));
[snip]

s/random_r/random/, s/initstate_r/initstate/ and remove `static struct
random_data rand_data'

Here is the man of `random_r()':
[snip]
The random_r() function is like random(3), except that instead of using
state information maintained in a global variable
[snip]

So use random without state information is OK.

But random(3) says:

The random() function should not be used in multithreaded programs
       where reproducible behavior is required.  Use random_r(3) for that
       purpose.
 

Signed-off-by: Hongxu Jia <hongxu.jia@windriver.com>
---
 src/main.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/main.c b/src/main.c
index f60b4d3..602c400 100644
--- a/src/main.c
+++ b/src/main.c
@@ -84,7 +84,6 @@ static char command[COMMAND_MAX];
 static int cmd_argc;
 static char **cmd_argv;
 static struct thread_pool pool;
-static struct random_data rand_data;
 static char rand_state[32];
 static pthread_mutex_t rand_mutex = PTHREAD_MUTEX_INITIALIZER;
 static const char *run_dir = NULL;
@@ -1386,16 +1385,15 @@ int get_rand(int a, int b);

 int get_rand(int a, int b)
 {
-       int32_t val;
-       int rv;
+       long int rv;

        pthread_mutex_lock(&rand_mutex);
-       rv = random_r(&rand_data, &val);
+       rv = random();
        pthread_mutex_unlock(&rand_mutex); 
        if (rv < 0)
                return rv;

But random_r() is accessed only via get_rand, using a mutex, so it looks
like we can replace it with random.

But why not use random() only when random_r() is not available?

Nir
 

-       return a + (int) (((float)(b - a + 1)) * val / (RAND_MAX+1.0));
+       return a + (int) (((float)(b - a + 1)) * rv / (RAND_MAX+1.0));
 }

 static void setup_host_name(void)
@@ -1405,9 +1403,7 @@ static void setup_host_name(void)
        uuid_t uu;

        memset(rand_state, 0, sizeof(rand_state));
-       memset(&rand_data, 0, sizeof(rand_data));
-
-       initstate_r(time(NULL), rand_state, sizeof(rand_state), &rand_data);
+       initstate(time(NULL), rand_state, sizeof(rand_state));

        /* use host name from command line */

--
2.8.1
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