musl/src/stdio/__stdio_write.c
Rich Felker b7a2761780 also ensure that write buffer is bounded when __stdio_write returns
assuming other code is correct, this should be a no-op, but better to
be safe...
2012-04-17 11:08:11 -04:00

45 lines
1 KiB
C

#include "stdio_impl.h"
#include <pthread.h>
static void cleanup(void *p)
{
FILE *f = p;
if (!f->lockcount) __unlockfile(f);
}
size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
{
struct iovec iovs[2] = {
{ .iov_base = f->wbase, .iov_len = f->wpos-f->wbase },
{ .iov_base = (void *)buf, .iov_len = len }
};
struct iovec *iov = iovs;
size_t rem = iov[0].iov_len + iov[1].iov_len;
int iovcnt = 2;
ssize_t cnt;
for (;;) {
pthread_cleanup_push(cleanup, f);
cnt = syscall_cp(SYS_writev, f->fd, iov, iovcnt);
pthread_cleanup_pop(0);
if (cnt == rem) {
f->wend = f->buf + f->buf_size;
f->wpos = f->wbase = f->buf;
return len;
}
if (cnt < 0) {
f->wpos = f->wbase = f->wend = 0;
f->flags |= F_ERR;
return iovcnt == 2 ? 0 : len-iov[0].iov_len;
}
rem -= cnt;
if (cnt > iov[0].iov_len) {
f->wpos = f->wbase = f->buf;
cnt -= iov[0].iov_len;
iov++; iovcnt--;
} else if (iovcnt == 2) {
f->wbase += cnt;
}
iov[0].iov_base = (char *)iov[0].iov_base + cnt;
iov[0].iov_len -= cnt;
}
}