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| author | Hristo Venev <hristo@venev.name> | |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | |
| commit | ||
| parent | ||
| tree | ||
| download | ||
cache: tolerate short writes in print_slot
sendfile() can return after a short read/write, so we may need to call
it more than once. As suggested in the manual page, we fall back to
read/write if sendfile fails with EINVAL or ENOSYS.
On the read/write path, use write_in_full which deals with short writes.
Signed-off-by: Hristo Venev <hristo@venev.name>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
| -rw-r--r-- | cache.c | 45 |
1 file changed, 25 insertions, 20 deletions
@@ -85,40 +85,45 @@ 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) { + off_t off; #ifdef HAVE_LINUX_SENDFILE - off_t start_off; - int ret; + off_t size; +#endif + + off = slot->keylen + 1; - start_off = slot->keylen + 1; +#ifdef HAVE_LINUX_SENDFILE + size = slot->cache_st.st_size; do { - ret = sendfile(STDOUT_FILENO, slot->cache_fd, &start_off, - slot->cache_st.st_size - start_off); + ssize_t ret; + ret = sendfile(STDOUT_FILENO, slot->cache_fd, &off, size - off); if (ret < 0) { if (errno == EAGAIN || errno == EINTR) continue; + /* Fall back to read/write on EINVAL or ENOSYS */ + if (errno == EINVAL || errno == ENOSYS) + 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 + ssize_t ret; + ret = xread(slot->cache_fd, slot->buf, sizeof(slot->buf)); + if (ret < 0) + return errno; + if (ret == 0) + return 0; + if (write_in_full(STDOUT_FILENO, slot->buf, ret) < 0) + return errno; + } while (1); } /* Check if the slot has expired */ |