mirror of
https://github.com/git/git
synced 2024-11-05 18:59:29 +00:00
4981fe750b
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>
82 lines
3 KiB
C
82 lines
3 KiB
C
#ifndef PKTLINE_H
|
|
#define PKTLINE_H
|
|
|
|
#include "git-compat-util.h"
|
|
#include "strbuf.h"
|
|
|
|
/*
|
|
* Write a packetized stream, where each line is preceded by
|
|
* its length (including the header) as a 4-byte hex number.
|
|
* A length of 'zero' means end of stream (and a length of 1-3
|
|
* would be an error).
|
|
*
|
|
* This is all pretty stupid, but we use this packetized line
|
|
* format to make a streaming format possible without ever
|
|
* over-running the read buffers. That way we'll never read
|
|
* into what might be the pack data (which should go to another
|
|
* process entirely).
|
|
*
|
|
* The writing side could use stdio, but since the reading
|
|
* side can't, we stay with pure read/write interfaces.
|
|
*/
|
|
void packet_flush(int fd);
|
|
void packet_write(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
|
|
void packet_buf_flush(struct strbuf *buf);
|
|
void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
|
|
|
|
/*
|
|
* 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:
|
|
*
|
|
* 1. Read error from descriptor.
|
|
*
|
|
* 2. Protocol error from the remote (e.g., bogus length characters).
|
|
*
|
|
* 3. Receiving a packet larger than "size" bytes.
|
|
*
|
|
* 4. Truncated output from the remote (e.g., we expected a packet but got
|
|
* EOF, or we got a partial packet followed by EOF).
|
|
*
|
|
* If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
|
|
* condition 4 (truncated input), but instead return -1. However, we will still
|
|
* die for the other 3 conditions.
|
|
*
|
|
* If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
|
|
* present) is removed from the buffer before returning.
|
|
*/
|
|
#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
|
|
#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
|
|
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
|
|
* CHOMP_NEWLINE option. The return value is NULL for a flush packet,
|
|
* and otherwise points to a static buffer (that may be overwritten by
|
|
* subsequent calls). If the size parameter is not NULL, the length of the
|
|
* packet is written to it.
|
|
*/
|
|
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];
|
|
|
|
#endif
|