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authorLukas Larsson <[email protected]>2014-12-10 10:36:51 +0100
committerLukas Larsson <[email protected]>2014-12-12 15:28:14 +0100
commitfb064173870a75d80402c3ad1e48dbaf59f086fb (patch)
tree38b48c4646a7c62ff359eee60606b5ea7c4c11bb /erts/emulator
parent0f4b940cd6173a1e991c2bce7a6004d95c52c088 (diff)
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erts: Make sure IOV_MAX is enforced for writev
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/sys/unix/sys.c26
1 files changed, 15 insertions, 11 deletions
diff --git a/erts/emulator/sys/unix/sys.c b/erts/emulator/sys/unix/sys.c
index eed93cb2a0..c51954be38 100644
--- a/erts/emulator/sys/unix/sys.c
+++ b/erts/emulator/sys/unix/sys.c
@@ -86,6 +86,14 @@ static erts_smp_rwmtx_t environ_rwmtx;
#define DISABLE_VFORK 0
#endif
+#if defined IOV_MAX
+#define MAXIOV IOV_MAX
+#elif defined UIO_MAXIOV
+#define MAXIOV UIO_MAXIOV
+#else
+#define MAXIOV 16
+#endif
+
#ifdef USE_THREADS
# ifdef ENABLE_CHILD_WAITER_THREAD
# define CHLDWTHR ENABLE_CHILD_WAITER_THREAD
@@ -2524,32 +2532,28 @@ fd_async(void *async_data)
SysIOVec *iov0;
SysIOVec *iov;
int iovlen;
- int iovcnt;
- int p;
+ int err;
/* much of this code is stolen from efile_drv:invoke_writev */
driver_pdl_lock(dd->blocking->pdl);
iov0 = driver_peekq(dd->port_num, &iovlen);
- /* Calculate iovcnt */
- for (p = 0, iovcnt = 0; iovcnt < iovlen;
- p += iov0[iovcnt++].iov_len)
- ;
+ iovlen = iovlen < MAXIOV ? iovlen : MAXIOV;
iov = erts_alloc_fnf(ERTS_ALC_T_SYS_WRITE_BUF,
- sizeof(SysIOVec)*iovcnt);
+ sizeof(SysIOVec)*iovlen);
if (!iov) {
res = -1;
- errno = ENOMEM;
- erts_free(ERTS_ALC_T_SYS_WRITE_BUF, iov);
+ err = ENOMEM;
driver_pdl_unlock(dd->blocking->pdl);
} else {
- memcpy(iov,iov0,iovcnt*sizeof(SysIOVec));
+ memcpy(iov,iov0,iovlen*sizeof(SysIOVec));
driver_pdl_unlock(dd->blocking->pdl);
res = writev(dd->ofd, iov, iovlen);
+ err = errno;
erts_free(ERTS_ALC_T_SYS_WRITE_BUF, iov);
}
dd->blocking->res = res;
- dd->blocking->err = errno;
+ dd->blocking->err = err;
}
void fd_ready_async(ErlDrvData drv_data,