sendfile() can return after a short read/write, so we may need to call
it more than once. Furthermore, not all files support sendfile(), so we
may need to fall back to read/write.
On the read/write path, use write_in_full which deals with short writes.
Signed-off-by: Hristo Venev <hri...@venev.name>
---
cache.c | 46 ++++++++++++++++++++++++----------------------
1 file changed, 24 insertions(+), 22 deletions(-)
diff --git a/cache.c b/cache.c
index 55199e8..85cfbd9 100644
--- a/cache.c
+++ b/cache.c
@@ -85,40 +85,42 @@ static int close_slot(struct cache_slot *slot)
/* Print the content of the active cache slot (but skip the key). */
static int print_slot(struct cache_slot *slot)
{
-#ifdef HAVE_LINUX_SENDFILE
- off_t start_off;
- int ret;
+ off_t off;
+ ssize_t i;
+
+ off = slot->keylen + 1;
- start_off = slot->keylen + 1;
+#ifdef HAVE_LINUX_SENDFILE
+ off_t size;
+ size = slot->cache_st.st_size;
do {
- ret = sendfile(STDOUT_FILENO, slot->cache_fd, &start_off,
- slot->cache_st.st_size - start_off);
- if (ret < 0) {
+ i = sendfile(STDOUT_FILENO, slot->cache_fd, &off, size - off);
+ if (i < 0) {
if (errno == EAGAIN || errno == EINTR)
continue;
+ /* Fall back to read/write on EINVAL */
+ if (errno == EINVAL)
+ break;
return errno;
}
- return 0;
+ if (off == size)
+ return 0;
} while (1);
-#else
- ssize_t i, j;
+#endif
- i = lseek(slot->cache_fd, slot->keylen + 1, SEEK_SET);
- if (i != slot->keylen + 1)
+ if (lseek(slot->cache_fd, off, SEEK_SET) != off)
return errno;
do {
- i = j = xread(slot->cache_fd, slot->buf, sizeof(slot->buf));
- if (i > 0)
- j = xwrite(STDOUT_FILENO, slot->buf, i);
- } while (i > 0 && j == i);
-
- if (i < 0 || j != i)
- return errno;
- else
- return 0;
-#endif
+ i = xread(slot->cache_fd, slot->buf, sizeof(slot->buf));
+ if (i < 0)
+ return errno;
+ if (i == 0)
+ return 0;
+ if (write_in_full(STDOUT_FILENO, slot->buf, i) < 0)
+ return errno;
+ } while (1);
}
/* Check if the slot has expired */
--
2.31.1
