Bug 3330205 Thread safety for bignum powers of 5
Change-Id: I739a06f9037a9fb643276f61601f0f3e192581b8
diff --git a/libc/stdlib/strtod.c b/libc/stdlib/strtod.c
index 2851506..ab637a1 100644
--- a/libc/stdlib/strtod.c
+++ b/libc/stdlib/strtod.c
@@ -754,6 +754,7 @@
}
static Bigint *p5s;
+ static pthread_mutex_t p5s_mutex = PTHREAD_MUTEX_INITIALIZER;
static Bigint *
pow5mult
@@ -775,11 +776,13 @@
if (!(k = (unsigned int) k >> 2))
return b;
+ mutex_lock(&p5s_mutex);
if (!(p5 = p5s)) {
/* first time */
p5 = i2b(625);
if (p5 == BIGINT_INVALID) {
Bfree(b);
+ mutex_unlock(&p5s_mutex);
return p5;
}
p5s = p5;
@@ -797,6 +800,7 @@
p51 = mult(p5,p5);
if (p51 == BIGINT_INVALID) {
Bfree(b);
+ mutex_unlock(&p5s_mutex);
return p51;
}
p5->next = p51;
@@ -804,6 +808,7 @@
}
p5 = p51;
}
+ mutex_unlock(&p5s_mutex);
return b;
}