[PATCH] pkt-line: Fix sparse errors and warnings

[PATCH] pkt-line: Fix sparse errors and warnings

[Ramsay Jones]

Sparse issues the following error and warnings:

    pkt-line.c:209:51: warning: Using plain integer as NULL pointer
    sideband.c:41:52: warning: Using plain integer as NULL pointer
    daemon.c:615:39: warning: Using plain integer as NULL pointer
    remote-curl.c:220:75: error: incompatible types for operation (>)
    remote-curl.c:220:75:    left side has type char *
    remote-curl.c:220:75:    right side has type int
    remote-curl.c:291:53: warning: Using plain integer as NULL pointer
    remote-curl.c:408:43: warning: Using plain integer as NULL pointer
    remote-curl.c:562:47: warning: Using plain integer as NULL pointer

All of these complaints "blame" to commit 17243606 ("pkt-line: share
buffer/descriptor reading implementation", 20-02-2013).

In order to suppress the warnings, we simply replace the integer
constant 0 with NULL.

In order to suppress the error message, we simply remove the "> 0" from
the while loop controlling expression.

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
---

Hi Jeff,

When you next re-roll your 'jk/pkt-line-cleanup' patches, could you
please squash this (or something like it) into commit 17243606
("pkt-line: share buffer/descriptor reading implementation", 20-02-2013).

Please check the resolution of the sparse error, remote-curl.c:220, since
I didn't think too deeply about it, making some assumptions ... ;-)

Note: the commit message mentions an strbuf_get_line() function, but
that is supposed to be packet_get_line(), right?

In addition, that commit adds the following code as part of function
get_packet_data():

+       /* Read up to "size" bytes from our source, whatever it is. */
+       if (src_buf && *src_buf) {
+               ret = size < *src_size ? size : *src_size;
+               memcpy(dst, *src_buf, ret);
+               *src_buf += size;
............................^^^^^
+               *src_size -= size;
+       } else {
+

This could lead to the source buffer pointer being incremented past the
"one past the end" of the buffer; ie to undefined behaviour. That use
of 'size', along with the one on the following line, should be 'ret' no?

ATB,
Ramsay Jones

 daemon.c      | 2 +-
 pkt-line.c    | 2 +-
 remote-curl.c | 8 ++++----
 sideband.c    | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/daemon.c b/daemon.c
index 9a241d9..82d5bf5 100644
--- a/daemon.c
+++ b/daemon.c
@@ -612,7 +612,7 @@ static int execute(void)
 		loginfo("Connection from %s:%s", addr, port);
 
 	alarm(init_timeout ? init_timeout : timeout);
-	pktlen = packet_read(0, NULL, 0, packet_buffer, sizeof(packet_buffer), 0);
+	pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 	alarm(0);
 
 	len = strlen(line);
diff --git a/pkt-line.c b/pkt-line.c
index 116d5f1..2793ecb 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -206,7 +206,7 @@ static char *packet_read_line_generic(int fd,
 
 char *packet_read_line(int fd, int *len_p)
 {
-	return packet_read_line_generic(fd, NULL, 0, len_p);
+	return packet_read_line_generic(fd, NULL, NULL, len_p);
 }
 
 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
diff --git a/remote-curl.c b/remote-curl.c
index 3d2b194..93a09a6 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -217,7 +217,7 @@ static struct discovery* discover_refs(const char *service, int for_push)
 		 * until a packet flush marker.  Ignore these now, but
 		 * in the future we might start to scan them.
 		 */
-		while (packet_read_line_buf(&last->buf, &last->len, NULL) > 0)
+		while (packet_read_line_buf(&last->buf, &last->len, NULL))
 			;
 
 		last->proto_git = 1;
@@ -288,7 +288,7 @@ static size_t rpc_out(void *ptr, size_t eltsize,
 
 	if (!avail) {
 		rpc->initial_buffer = 0;
-		avail = packet_read(rpc->out, NULL, 0, rpc->buf, rpc->alloc, 0);
+		avail = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
 		if (!avail)
 			return 0;
 		rpc->pos = 0;
@@ -405,7 +405,7 @@ static int post_rpc(struct rpc_state *rpc)
 			break;
 		}
 
-		n = packet_read(rpc->out, 0, NULL, buf, left, 0);
+		n = packet_read(rpc->out, NULL, NULL, buf, left, 0);
 		if (!n)
 			break;
 		rpc->len += n;
@@ -559,7 +559,7 @@ static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
 	rpc->hdr_accept = strbuf_detach(&buf, NULL);
 
 	while (!err) {
-		int n = packet_read(rpc->out, 0, NULL, rpc->buf, rpc->alloc, 0);
+		int n = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
 		if (!n)
 			break;
 		rpc->pos = 0;
diff --git a/sideband.c b/sideband.c
index 857954c..d1125f5 100644
--- a/sideband.c
+++ b/sideband.c
@@ -38,7 +38,7 @@ int recv_sideband(const char *me, int in_stream, int out)
 
 	while (1) {
 		int band, len;
-		len = packet_read(in_stream, NULL, 0, buf + pf, LARGE_PACKET_MAX, 0);
+		len = packet_read(in_stream, NULL, NULL, buf + pf, LARGE_PACKET_MAX, 0);
 		if (len == 0)
 			break;
 		if (len < 1) {
-- 
1.8.1

Re: [PATCH] pkt-line: Fix sparse errors and warnings

[Jeff King]

On Sat, Feb 23, 2013 at 06:44:04PM +0000, Ramsay Jones wrote:

> Sparse issues the following error and warnings:
> 
>     pkt-line.c:209:51: warning: Using plain integer as NULL pointer
>     sideband.c:41:52: warning: Using plain integer as NULL pointer
>     daemon.c:615:39: warning: Using plain integer as NULL pointer
>     remote-curl.c:220:75: error: incompatible types for operation (>)
>     remote-curl.c:220:75:    left side has type char *
>     remote-curl.c:220:75:    right side has type int
>     remote-curl.c:291:53: warning: Using plain integer as NULL pointer
>     remote-curl.c:408:43: warning: Using plain integer as NULL pointer
>     remote-curl.c:562:47: warning: Using plain integer as NULL pointer
> 
> All of these complaints "blame" to commit 17243606 ("pkt-line: share
> buffer/descriptor reading implementation", 20-02-2013).
> 
> In order to suppress the warnings, we simply replace the integer
> constant 0 with NULL.

Thanks for catching. This was just a think-o on my part; we want to pass
(NULL, 0) as the (buf, len) pair, but of course we are passing pointers
to them, so it is actually (NULL, NULL). And yes, I made sure the
function correctly handles both a NULL pointer-to-buf and a NULL
pointer-to-pointer-to-buf (and we do not even care about the
pointer-to-len unless the buf pointer is valid).

So no bug, but definitely a reasonable cleanup.

Oddly, you seemed to miss the one in connect.c (which my sparse does
detect).

> In order to suppress the error message, we simply remove the "> 0" from
> the while loop controlling expression.

Yeah, that is the right thing to do. The code that's there isn't wrong,
but I agree that checking "ptr != NULL" (i.e., just "ptr") is much more
sane than "ptr > 0" (and is just a leftover that I missed during
refactoring the patch).

> When you next re-roll your 'jk/pkt-line-cleanup' patches, could you
> please squash this (or something like it) into commit 17243606
> ("pkt-line: share buffer/descriptor reading implementation", 20-02-2013).

I don't think we otherwise need a re-roll. Junio hasn't merged the
series to next yet, so I've included an updated patch 15 below with your
changes (your patch, the missing connect.c fix, the commit message fix,
and the size/ret thing below).

> In addition, that commit adds the following code as part of function
> get_packet_data():
> 
> +       /* Read up to "size" bytes from our source, whatever it is. */
> +       if (src_buf && *src_buf) {
> +               ret = size < *src_size ? size : *src_size;
> +               memcpy(dst, *src_buf, ret);
> +               *src_buf += size;
> ............................^^^^^
> +               *src_size -= size;
> +       } else {
> +
> 
> This could lead to the source buffer pointer being incremented past the
> "one past the end" of the buffer; ie to undefined behaviour. That use
> of 'size', along with the one on the following line, should be 'ret' no?

Yeah, thanks for catching. We just die immediately afterwards anyway,
and sane systems do not care what kind of junk you put into a pointer
unless you dereference. But clearly it is supposed to be "ret".

Thanks for the report. Clearly I should start running "make sparse" more
often (the reason I don't is that it produces dozens of complaints about
constants in /usr/include/bits/xopen_lim.h, which I could obviously care
less about; I should look into suppressing that).

Updated patch 15/19 is below.

-- >8 --
Subject: [PATCH] pkt-line: share buffer/descriptor reading implementation

The packet_read function reads from a descriptor. The
packet_get_line function is similar, but reads from an
in-memory buffer, and uses a completely separate
implementation. This patch teaches the generic packet_read
function to accept either source, and we can do away with
packet_get_line's implementation.

There are two other differences to account for between the
old and new functions. The first is that we used to read
into a strbuf, but now read into a fixed size buffer. The
only two callers are fine with that, and in fact it
simplifies their code, since they can use the same
static-buffer interface as the rest of the packet_read_line
callers (and we provide a similar convenience wrapper for
reading from a buffer rather than a descriptor).

This is technically an externally-visible behavior change in
that we used to accept arbitrary sized packets up to 65532
bytes, and now cap out at LARGE_PACKET_MAX, 65520. In
practice this doesn't matter, as we use it only for parsing
smart-http headers (of which there is exactly one defined,
and it is small and fixed-size). And any extension headers
would be breaking the protocol to go over LARGE_PACKET_MAX
anyway.

The other difference is that packet_get_line would return
on error rather than dying. However, both callers of
packet_get_line are actually improved by dying.

The first caller does its own error checking, but we can
drop that; as a result, we'll actually get more specific
reporting about protocol breakage when packet_read dies
internally. The only downside is that packet_read will not
print the smart-http URL that failed, but that's not a big
deal; anybody not debugging can already see the remote's URL
already, and anybody debugging would want to run with
GIT_CURL_VERBOSE anyway to see way more information.

The second caller, which is just trying to skip past any
extra smart-http headers (of which there are none defined,
but which we allow to keep room for future expansion), did
not error check at all. As a result, it would treat an error
just like a flush packet. The resulting mess would generally
cause an error later in get_remote_heads, but now we get
error reporting much closer to the source of the problem.

Brown-paper-bag-fixes-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 connect.c     |  3 ++-
 daemon.c      |  2 +-
 pkt-line.c    | 76 +++++++++++++++++++++++++++++------------------------------
 pkt-line.h    | 23 +++++++++++++-----
 remote-curl.c | 22 ++++++++---------
 sideband.c    |  2 +-
 6 files changed, 69 insertions(+), 59 deletions(-)

diff --git a/connect.c b/connect.c
index 611ffb4..3d99999 100644
--- a/connect.c
+++ b/connect.c
@@ -76,7 +76,8 @@ struct ref **get_remote_heads(int in, struct ref **list,
 		int len, name_len;
 		char *buffer = packet_buffer;
 
-		len = packet_read(in, packet_buffer, sizeof(packet_buffer),
+		len = packet_read(in, NULL, NULL,
+				  packet_buffer, sizeof(packet_buffer),
 				  PACKET_READ_GENTLE_ON_EOF |
 				  PACKET_READ_CHOMP_NEWLINE);
 		if (len < 0)
diff --git a/daemon.c b/daemon.c
index 3f70e79..82d5bf5 100644
--- a/daemon.c
+++ b/daemon.c
@@ -612,7 +612,7 @@ static int execute(void)
 		loginfo("Connection from %s:%s", addr, port);
 
 	alarm(init_timeout ? init_timeout : timeout);
-	pktlen = packet_read(0, packet_buffer, sizeof(packet_buffer), 0);
+	pktlen = packet_read(0, NULL, NULL, packet_buffer, sizeof(packet_buffer), 0);
 	alarm(0);
 
 	len = strlen(line);
diff --git a/pkt-line.c b/pkt-line.c
index 55fb688..70f1950 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -104,12 +104,28 @@ static int safe_read(int fd, void *buffer, unsigned size, int options)
 	strbuf_add(buf, buffer, n);
 }
 
-static int safe_read(int fd, void *buffer, unsigned size, int options)
+static int get_packet_data(int fd, char **src_buf, size_t *src_size,
+			   void *dst, unsigned size, int options)
 {
-	ssize_t ret = read_in_full(fd, buffer, size);
-	if (ret < 0)
-		die_errno("read error");
-	else if (ret < size) {
+	ssize_t ret;
+
+	if (fd >= 0 && src_buf && *src_buf)
+		die("BUG: multiple sources given to packet_read");
+
+	/* Read up to "size" bytes from our source, whatever it is. */
+	if (src_buf && *src_buf) {
+		ret = size < *src_size ? size : *src_size;
+		memcpy(dst, *src_buf, ret);
+		*src_buf += ret;
+		*src_size -= ret;
+	} else {
+		ret = read_in_full(fd, dst, size);
+		if (ret < 0)
+			die_errno("read error");
+	}
+
+	/* And complain if we didn't get enough bytes to satisfy the read. */
+	if (ret < size) {
 		if (options & PACKET_READ_GENTLE_ON_EOF)
 			return -1;
 
@@ -144,12 +160,13 @@ int packet_read(int fd, char *buffer, unsigned size, int options)
 	return len;
 }
 
-int packet_read(int fd, char *buffer, unsigned size, int options)
+int packet_read(int fd, char **src_buf, size_t *src_len,
+		char *buffer, unsigned size, int options)
 {
 	int len, ret;
 	char linelen[4];
 
-	ret = safe_read(fd, linelen, 4, options);
+	ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
 	if (ret < 0)
 		return ret;
 	len = packet_length(linelen);
@@ -162,7 +179,7 @@ int packet_read(int fd, char *buffer, unsigned size, int options)
 	len -= 4;
 	if (len >= size)
 		die("protocol error: bad line length %d", len);
-	ret = safe_read(fd, buffer, len, options);
+	ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
 	if (ret < 0)
 		return ret;
 
@@ -175,41 +192,24 @@ int packet_get_line(struct strbuf *out,
 	return len;
 }
 
-char *packet_read_line(int fd, int *len_p)
+static char *packet_read_line_generic(int fd,
+				      char **src, size_t *src_len,
+				      int *dst_len)
 {
-	int len = packet_read(fd, packet_buffer, sizeof(packet_buffer),
+	int len = packet_read(fd, src, src_len,
+			      packet_buffer, sizeof(packet_buffer),
 			      PACKET_READ_CHOMP_NEWLINE);
-	if (len_p)
-		*len_p = len;
+	if (dst_len)
+		*dst_len = len;
 	return len ? packet_buffer : NULL;
 }
 
-int packet_get_line(struct strbuf *out,
-	char **src_buf, size_t *src_len)
+char *packet_read_line(int fd, int *len_p)
 {
-	int len;
-
-	if (*src_len < 4)
-		return -1;
-	len = packet_length(*src_buf);
-	if (len < 0)
-		return -1;
-	if (!len) {
-		*src_buf += 4;
-		*src_len -= 4;
-		packet_trace("0000", 4, 0);
-		return 0;
-	}
-	if (*src_len < len)
-		return -2;
-
-	*src_buf += 4;
-	*src_len -= 4;
-	len -= 4;
+	return packet_read_line_generic(fd, NULL, NULL, len_p);
+}
 
-	strbuf_add(out, *src_buf, len);
-	*src_buf += len;
-	*src_len -= len;
-	packet_trace(out->buf, out->len, 0);
-	return len;
+char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
+{
+	return packet_read_line_generic(-1, src, src_len, dst_len);
 }
diff --git a/pkt-line.h b/pkt-line.h
index fa93e32..0a838d1 100644
--- a/pkt-line.h
+++ b/pkt-line.h
@@ -25,9 +25,16 @@ void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((f
 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
 
 /*
- * Read a packetized line from the descriptor into the buffer, which must be at
- * least size bytes long. The return value specifies the number of bytes read
- * into the buffer.
+ * Read a packetized line into the buffer, which must be at least size bytes
+ * long. The return value specifies the number of bytes read into the buffer.
+ *
+ * If src_buffer is not NULL (and nor is *src_buffer), it should point to a
+ * buffer containing the packet data to parse, of at least *src_len bytes.
+ * After the function returns, src_buf will be incremented and src_len
+ * decremented by the number of bytes consumed.
+ *
+ * If src_buffer (or *src_buffer) is NULL, then data is read from the
+ * descriptor "fd".
  *
  * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
  * of the following conditions:
@@ -50,7 +57,8 @@ void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((f
  */
 #define PACKET_READ_GENTLE_ON_EOF (1u<<0)
 #define PACKET_READ_CHOMP_NEWLINE (1u<<1)
-int packet_read(int fd, char *buffer, unsigned size, int options);
+int packet_read(int fd, char **src_buffer, size_t *src_len, char
+		*buffer, unsigned size, int options);
 
 /*
  * Convenience wrapper for packet_read that is not gentle, and sets the
@@ -61,11 +69,14 @@ extern char packet_buffer[LARGE_PACKET_MAX];
  */
 char *packet_read_line(int fd, int *size);
 
+/*
+ * Same as packet_read_line, but read from a buf rather than a descriptor;
+ * see packet_read for details on how src_* is used.
+ */
+char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
 
 #define DEFAULT_PACKET_MAX 1000
 #define LARGE_PACKET_MAX 65520
 extern char packet_buffer[LARGE_PACKET_MAX];
 
-int packet_get_line(struct strbuf *out, char **src_buf, size_t *src_len);
-
 #endif
diff --git a/remote-curl.c b/remote-curl.c
index b28f965..c8379a5 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -138,28 +138,26 @@ static struct discovery* discover_refs(const char *service)
 	if (maybe_smart &&
 	    (5 <= last->len && last->buf[4] == '#') &&
 	    !strbuf_cmp(&exp, &type)) {
+		char *line;
+
 		/*
 		 * smart HTTP response; validate that the service
 		 * pkt-line matches our request.
 		 */
-		if (packet_get_line(&buffer, &last->buf, &last->len) <= 0)
-			die("%s has invalid packet header", refs_url);
-		if (buffer.len && buffer.buf[buffer.len - 1] == '\n')
-			strbuf_setlen(&buffer, buffer.len - 1);
+		line = packet_read_line_buf(&last->buf, &last->len, NULL);
 
 		strbuf_reset(&exp);
 		strbuf_addf(&exp, "# service=%s", service);
-		if (strbuf_cmp(&exp, &buffer))
-			die("invalid server response; got '%s'", buffer.buf);
+		if (strcmp(line, exp.buf))
+			die("invalid server response; got '%s'", line);
 		strbuf_release(&exp);
 
 		/* The header can include additional metadata lines, up
 		 * until a packet flush marker.  Ignore these now, but
 		 * in the future we might start to scan them.
 		 */
-		strbuf_reset(&buffer);
-		while (packet_get_line(&buffer, &last->buf, &last->len) > 0)
-			strbuf_reset(&buffer);
+		while (packet_read_line_buf(&last->buf, &last->len, NULL))
+			;
 
 		last->proto_git = 1;
 	}
@@ -308,7 +306,7 @@ static size_t rpc_out(void *ptr, size_t eltsize,
 
 	if (!avail) {
 		rpc->initial_buffer = 0;
-		avail = packet_read(rpc->out, rpc->buf, rpc->alloc, 0);
+		avail = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
 		if (!avail)
 			return 0;
 		rpc->pos = 0;
@@ -425,7 +423,7 @@ static int post_rpc(struct rpc_state *rpc)
 			break;
 		}
 
-		n = packet_read(rpc->out, buf, left, 0);
+		n = packet_read(rpc->out, NULL, NULL, buf, left, 0);
 		if (!n)
 			break;
 		rpc->len += n;
@@ -579,7 +577,7 @@ static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
 	rpc->hdr_accept = strbuf_detach(&buf, NULL);
 
 	while (!err) {
-		int n = packet_read(rpc->out, rpc->buf, rpc->alloc, 0);
+		int n = packet_read(rpc->out, NULL, NULL, rpc->buf, rpc->alloc, 0);
 		if (!n)
 			break;
 		rpc->pos = 0;
diff --git a/sideband.c b/sideband.c
index 15cc1ae..d1125f5 100644
--- a/sideband.c
+++ b/sideband.c
@@ -38,7 +38,7 @@ int recv_sideband(const char *me, int in_stream, int out)
 
 	while (1) {
 		int band, len;
-		len = packet_read(in_stream, buf + pf, LARGE_PACKET_MAX, 0);
+		len = packet_read(in_stream, NULL, NULL, buf + pf, LARGE_PACKET_MAX, 0);
 		if (len == 0)
 			break;
 		if (len < 1) {
-- 
1.8.1.4.4.g265d2fa

Re: [PATCH] pkt-line: Fix sparse errors and warnings

[Jeff King]

On Sat, Feb 23, 2013 at 05:31:34PM -0500, Jeff King wrote:

> On Sat, Feb 23, 2013 at 06:44:04PM +0000, Ramsay Jones wrote:
> 
> > Sparse issues the following error and warnings:
> > 
> >     pkt-line.c:209:51: warning: Using plain integer as NULL pointer
> >     sideband.c:41:52: warning: Using plain integer as NULL pointer
> >     daemon.c:615:39: warning: Using plain integer as NULL pointer
> >     remote-curl.c:220:75: error: incompatible types for operation (>)
> >     remote-curl.c:220:75:    left side has type char *
> >     remote-curl.c:220:75:    right side has type int
> >     remote-curl.c:291:53: warning: Using plain integer as NULL pointer
> >     remote-curl.c:408:43: warning: Using plain integer as NULL pointer
> >     remote-curl.c:562:47: warning: Using plain integer as NULL pointer
> > 
> > All of these complaints "blame" to commit 17243606 ("pkt-line: share
> > buffer/descriptor reading implementation", 20-02-2013).
> > 
> > In order to suppress the warnings, we simply replace the integer
> > constant 0 with NULL.
> [...]
> Oddly, you seemed to miss the one in connect.c (which my sparse does
> detect).

Ah, I saw why as soon as I finished off the rebase: that (NULL, 0) goes
away in the very next patch, and you probably ran sparse just on the tip
of the topic (via pu). I still think it's worth fixing since we are
squashing anyway. Junio, it will give you a trivial conflict on patch
16, but you can just resolve in favor of what patch 16 does. If it's
easier, here's the revised patch 16:

-- >8 --
Subject: [PATCH] teach get_remote_heads to read from a memory buffer

Now that we can read packet data from memory as easily as a
descriptor, get_remote_heads can take either one as a
source. This will allow further refactoring in remote-curl.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/fetch-pack.c | 2 +-
 builtin/send-pack.c  | 2 +-
 cache.h              | 4 +++-
 connect.c            | 6 +++---
 remote-curl.c        | 2 +-
 transport.c          | 6 +++---
 6 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c
index c21cc2c..03ed2ca 100644
--- a/builtin/fetch-pack.c
+++ b/builtin/fetch-pack.c
@@ -125,7 +125,7 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
 				   args.verbose ? CONNECT_VERBOSE : 0);
 	}
 
-	get_remote_heads(fd[0], &ref, 0, NULL);
+	get_remote_heads(fd[0], NULL, 0, &ref, 0, NULL);
 
 	ref = fetch_pack(&args, fd, conn, ref, dest,
 			 &sought, pack_lockfile_ptr);
diff --git a/builtin/send-pack.c b/builtin/send-pack.c
index 8778519..152c4ea 100644
--- a/builtin/send-pack.c
+++ b/builtin/send-pack.c
@@ -207,7 +207,7 @@ int cmd_send_pack(int argc, const char **argv, const char *prefix)
 
 	memset(&extra_have, 0, sizeof(extra_have));
 
-	get_remote_heads(fd[0], &remote_refs, REF_NORMAL, &extra_have);
+	get_remote_heads(fd[0], NULL, 0, &remote_refs, REF_NORMAL, &extra_have);
 
 	transport_verify_remote_names(nr_refspecs, refspecs);
 
diff --git a/cache.h b/cache.h
index e493563..db646a2 100644
--- a/cache.h
+++ b/cache.h
@@ -1049,7 +1049,9 @@ struct extra_have_objects {
 	int nr, alloc;
 	unsigned char (*array)[20];
 };
-extern struct ref **get_remote_heads(int in, struct ref **list, unsigned int flags, struct extra_have_objects *);
+extern struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
+				     struct ref **list, unsigned int flags,
+				     struct extra_have_objects *);
 extern int server_supports(const char *feature);
 extern int parse_feature_request(const char *features, const char *feature);
 extern const char *server_feature_value(const char *feature, int *len_ret);
diff --git a/connect.c b/connect.c
index 3d99999..f57efd0 100644
--- a/connect.c
+++ b/connect.c
@@ -62,8 +62,8 @@ static void die_initial_contact(int got_at_least_one_head)
 /*
  * Read all the refs from the other end
  */
-struct ref **get_remote_heads(int in, struct ref **list,
-			      unsigned int flags,
+struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
+			      struct ref **list, unsigned int flags,
 			      struct extra_have_objects *extra_have)
 {
 	int got_at_least_one_head = 0;
@@ -76,7 +76,7 @@ struct ref **get_remote_heads(int in, struct ref **list,
 		int len, name_len;
 		char *buffer = packet_buffer;
 
-		len = packet_read(in, NULL, NULL,
+		len = packet_read(in, &src_buf, &src_len,
 				  packet_buffer, sizeof(packet_buffer),
 				  PACKET_READ_GENTLE_ON_EOF |
 				  PACKET_READ_CHOMP_NEWLINE);
diff --git a/remote-curl.c b/remote-curl.c
index c8379a5..24c8626 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -192,7 +192,7 @@ static struct ref *parse_git_refs(struct discovery *heads, int for_push)
 
 	if (start_async(&async))
 		die("cannot start thread to parse advertised refs");
-	get_remote_heads(async.out, &list,
+	get_remote_heads(async.out, NULL, 0, &list,
 			for_push ? REF_NORMAL : 0, NULL);
 	close(async.out);
 	if (finish_async(&async))
diff --git a/transport.c b/transport.c
index 886ffd8..62df466 100644
--- a/transport.c
+++ b/transport.c
@@ -507,7 +507,7 @@ static struct ref *get_refs_via_connect(struct transport *transport, int for_pus
 	struct ref *refs;
 
 	connect_setup(transport, for_push, 0);
-	get_remote_heads(data->fd[0], &refs,
+	get_remote_heads(data->fd[0], NULL, 0, &refs,
 			 for_push ? REF_NORMAL : 0, &data->extra_have);
 	data->got_remote_heads = 1;
 
@@ -541,7 +541,7 @@ static int fetch_refs_via_pack(struct transport *transport,
 
 	if (!data->got_remote_heads) {
 		connect_setup(transport, 0, 0);
-		get_remote_heads(data->fd[0], &refs_tmp, 0, NULL);
+		get_remote_heads(data->fd[0], NULL, 0, &refs_tmp, 0, NULL);
 		data->got_remote_heads = 1;
 	}
 
@@ -799,7 +799,7 @@ static int git_transport_push(struct transport *transport, struct ref *remote_re
 		struct ref *tmp_refs;
 		connect_setup(transport, 1, 0);
 
-		get_remote_heads(data->fd[0], &tmp_refs, REF_NORMAL, NULL);
+		get_remote_heads(data->fd[0], NULL, 0, &tmp_refs, REF_NORMAL, NULL);
 		data->got_remote_heads = 1;
 	}
 
-- 
1.8.1.4.4.g265d2fa

Re: [PATCH] pkt-line: Fix sparse errors and warnings

[Junio C Hamano]

Jeff King <peff@peff.net> writes:

>> Oddly, you seemed to miss the one in connect.c (which my sparse does
>> detect).
>
> Ah, I saw why as soon as I finished off the rebase: that (NULL, 0) goes
> away in the very next patch,...

Yeah, I noticed that myself while replacing 15.  The patch in the
message I am responding to seems to match byte-for-byte with the
result of my rebase, too.

Thanks.

Re: [PATCH] pkt-line: Fix sparse errors and warnings

[Ramsay Jones]

Jeff King wrote:
> On Sat, Feb 23, 2013 at 05:31:34PM -0500, Jeff King wrote:
> 
>> On Sat, Feb 23, 2013 at 06:44:04PM +0000, Ramsay Jones wrote:
>>
>>> Sparse issues the following error and warnings:
>>>
>>>     pkt-line.c:209:51: warning: Using plain integer as NULL pointer
>>>     sideband.c:41:52: warning: Using plain integer as NULL pointer
>>>     daemon.c:615:39: warning: Using plain integer as NULL pointer
>>>     remote-curl.c:220:75: error: incompatible types for operation (>)
>>>     remote-curl.c:220:75:    left side has type char *
>>>     remote-curl.c:220:75:    right side has type int
>>>     remote-curl.c:291:53: warning: Using plain integer as NULL pointer
>>>     remote-curl.c:408:43: warning: Using plain integer as NULL pointer
>>>     remote-curl.c:562:47: warning: Using plain integer as NULL pointer
>>>
>>> All of these complaints "blame" to commit 17243606 ("pkt-line: share
>>> buffer/descriptor reading implementation", 20-02-2013).
>>>
>>> In order to suppress the warnings, we simply replace the integer
>>> constant 0 with NULL.
>> [...]
>> Oddly, you seemed to miss the one in connect.c (which my sparse does
>> detect).
> 
> Ah, I saw why as soon as I finished off the rebase: that (NULL, 0) goes
> away in the very next patch, and you probably ran sparse just on the tip
> of the topic (via pu). 

Yes, sorry I should have mentioned that! Ahem, *blush* [Having created and
tested the patch (including running "make test") on the tip of pu, I applied
the patch directly to commit 17243606 (using git-am). Since it applied
cleanly and git-show looked OK, I said to myself "yep, that's OK, send it" ;-) ]

>                         I still think it's worth fixing since we are
> squashing anyway. Junio, it will give you a trivial conflict on patch
> 16, but you can just resolve in favor of what patch 16 does. If it's
> easier, here's the revised patch 16:

So, sorry for being a bit sloppy guys!

ATB,
Ramsay Jones

Re: [PATCH] pkt-line: Fix sparse errors and warnings

[Ramsay Jones]

Jeff King wrote:
> Thanks for the report. Clearly I should start running "make sparse" more
> often (the reason I don't is that it produces dozens of complaints about
> constants in /usr/include/bits/xopen_lim.h, which I could obviously care
> less about; I should look into suppressing that).

Hmm, I'm guessing you are on an 64bit system; if so, and you are running
the release version of sparse (v0.4.4 Nov 2011), I would clone the sparse
repo [1] and build from source. There have been many improvements to the
64bit support since the last release (I hear it was unusable). [Note: I
can't confirm that - I'm currently stuck on 32bits!]

ATB,
Ramsay Jones

[1] git://git.kernel.org/pub/scm/devel/sparse/sparse.git (which had been
dormant for quite some time, but sprang to life again last week).