Yiannis Marangos <yiannis.marangos@xxxxxxxxx> writes:
> xpread() and xpwrite() pay attention to EAGAIN/EINTR, so they will resume
> automatically on interrupted call.
We do not even use pwrite(); please don't add anything unnecessary
and unexercised, like xpwrite(), as potential bugs in it will go
unnoticed long after its introduction until it first gets used.
> diff --git a/builtin/index-pack.c b/builtin/index-pack.c
> index b9f6e12..1bac0f5 100644
> --- a/builtin/index-pack.c
> +++ b/builtin/index-pack.c
> @@ -542,7 +542,7 @@ static void *unpack_data(struct object_entry *obj,
>
> do {
> ssize_t n = (len < 64*1024) ? len : 64*1024;
> - n = pread(pack_fd, inbuf, n, from);
> + n = xpread(pack_fd, inbuf, n, from);
> if (n < 0)
> die_errno(_("cannot pread pack file"));
> if (!n)
OK.
> diff --git a/compat/mmap.c b/compat/mmap.c
> index c9d46d1..7f662fe 100644
> --- a/compat/mmap.c
> +++ b/compat/mmap.c
> @@ -14,7 +14,7 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
> }
>
> while (n < length) {
> - ssize_t count = pread(fd, (char *)start + n, length - n, offset + n);
> + ssize_t count = xpread(fd, (char *)start + n, length - n, offset + n);
>
> if (count == 0) {
> memset((char *)start+n, 0, length-n);
> @@ -22,8 +22,6 @@ void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t of
> }
>
> if (count < 0) {
> - if (errno == EAGAIN || errno == EINTR)
> - continue;
> free(start);
> errno = EACCES;
> return MAP_FAILED;
OK.
> diff --git a/wrapper.c b/wrapper.c
> index 0cc5636..25b7419 100644
> --- a/wrapper.c
> +++ b/wrapper.c
> @@ -174,6 +174,42 @@ ssize_t xwrite(int fd, const void *buf, size_t len)
> }
> }
>
> +/*
> + * xpread() is the same as pread(), but it automatically restarts pread()
> + * operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
> + * NOT GUARANTEE that "len" bytes is read even if the data is available.
> + */
> +ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
> +{
> + ssize_t nr;
> + if (len > MAX_IO_SIZE)
> + len = MAX_IO_SIZE;
> + while (1) {
> + nr = pread(fd, buf, len, offset);
> + if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
> + continue;
> + return nr;
> + }
> +}
OK.
Thanks.
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