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![Lars Schneider](/assets/img/avatar_default.png)
write_packetized_from_fd() and write_packetized_from_buf() write a stream of packets. All content packets use the maximal packet size except for the last one. After the last content packet a `flush` control packet is written. read_packetized_to_strbuf() reads arbitrary sized packets until it detects a `flush` packet. Signed-off-by: Lars Schneider <larsxschneider@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
362 lines
8.2 KiB
C
362 lines
8.2 KiB
C
#include "cache.h"
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#include "pkt-line.h"
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#include "run-command.h"
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char packet_buffer[LARGE_PACKET_MAX];
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static const char *packet_trace_prefix = "git";
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static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
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static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);
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void packet_trace_identity(const char *prog)
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{
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packet_trace_prefix = xstrdup(prog);
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}
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static const char *get_trace_prefix(void)
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{
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return in_async() ? "sideband" : packet_trace_prefix;
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}
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static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
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{
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if (!sideband) {
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trace_verbatim(&trace_pack, buf, len);
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return 1;
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} else if (len && *buf == '\1') {
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trace_verbatim(&trace_pack, buf + 1, len - 1);
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return 1;
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} else {
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/* it's another non-pack sideband */
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return 0;
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}
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}
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static void packet_trace(const char *buf, unsigned int len, int write)
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{
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int i;
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struct strbuf out;
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static int in_pack, sideband;
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if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
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return;
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if (in_pack) {
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if (packet_trace_pack(buf, len, sideband))
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return;
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} else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
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in_pack = 1;
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sideband = *buf == '\1';
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packet_trace_pack(buf, len, sideband);
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/*
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* Make a note in the human-readable trace that the pack data
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* started.
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*/
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buf = "PACK ...";
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len = strlen(buf);
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}
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if (!trace_want(&trace_packet))
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return;
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/* +32 is just a guess for header + quoting */
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strbuf_init(&out, len+32);
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strbuf_addf(&out, "packet: %12s%c ",
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get_trace_prefix(), write ? '>' : '<');
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/* XXX we should really handle printable utf8 */
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for (i = 0; i < len; i++) {
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/* suppress newlines */
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if (buf[i] == '\n')
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continue;
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if (buf[i] >= 0x20 && buf[i] <= 0x7e)
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strbuf_addch(&out, buf[i]);
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else
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strbuf_addf(&out, "\\%o", buf[i]);
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}
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strbuf_addch(&out, '\n');
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trace_strbuf(&trace_packet, &out);
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strbuf_release(&out);
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}
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/*
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* If we buffered things up above (we don't, but we should),
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* we'd flush it here
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*/
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void packet_flush(int fd)
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{
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packet_trace("0000", 4, 1);
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write_or_die(fd, "0000", 4);
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}
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int packet_flush_gently(int fd)
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{
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packet_trace("0000", 4, 1);
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if (write_in_full(fd, "0000", 4) == 4)
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return 0;
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return error("flush packet write failed");
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}
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void packet_buf_flush(struct strbuf *buf)
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{
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packet_trace("0000", 4, 1);
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strbuf_add(buf, "0000", 4);
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}
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static void set_packet_header(char *buf, const int size)
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{
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static char hexchar[] = "0123456789abcdef";
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#define hex(a) (hexchar[(a) & 15])
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buf[0] = hex(size >> 12);
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buf[1] = hex(size >> 8);
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buf[2] = hex(size >> 4);
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buf[3] = hex(size);
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#undef hex
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}
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static void format_packet(struct strbuf *out, const char *fmt, va_list args)
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{
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size_t orig_len, n;
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orig_len = out->len;
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strbuf_addstr(out, "0000");
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strbuf_vaddf(out, fmt, args);
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n = out->len - orig_len;
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if (n > LARGE_PACKET_MAX)
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die("protocol error: impossibly long line");
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set_packet_header(&out->buf[orig_len], n);
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packet_trace(out->buf + orig_len + 4, n - 4, 1);
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}
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static int packet_write_fmt_1(int fd, int gently,
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const char *fmt, va_list args)
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{
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struct strbuf buf = STRBUF_INIT;
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ssize_t count;
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format_packet(&buf, fmt, args);
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count = write_in_full(fd, buf.buf, buf.len);
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if (count == buf.len)
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return 0;
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if (!gently) {
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check_pipe(errno);
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die_errno("packet write with format failed");
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}
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return error("packet write with format failed");
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}
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void packet_write_fmt(int fd, const char *fmt, ...)
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{
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va_list args;
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va_start(args, fmt);
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packet_write_fmt_1(fd, 0, fmt, args);
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va_end(args);
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}
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int packet_write_fmt_gently(int fd, const char *fmt, ...)
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{
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int status;
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va_list args;
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va_start(args, fmt);
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status = packet_write_fmt_1(fd, 1, fmt, args);
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va_end(args);
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return status;
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}
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static int packet_write_gently(const int fd_out, const char *buf, size_t size)
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{
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static char packet_write_buffer[LARGE_PACKET_MAX];
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size_t packet_size;
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if (size > sizeof(packet_write_buffer) - 4)
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return error("packet write failed - data exceeds max packet size");
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packet_trace(buf, size, 1);
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packet_size = size + 4;
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set_packet_header(packet_write_buffer, packet_size);
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memcpy(packet_write_buffer + 4, buf, size);
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if (write_in_full(fd_out, packet_write_buffer, packet_size) == packet_size)
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return 0;
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return error("packet write failed");
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}
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void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
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{
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va_list args;
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va_start(args, fmt);
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format_packet(buf, fmt, args);
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va_end(args);
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}
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int write_packetized_from_fd(int fd_in, int fd_out)
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{
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static char buf[LARGE_PACKET_DATA_MAX];
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int err = 0;
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ssize_t bytes_to_write;
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while (!err) {
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bytes_to_write = xread(fd_in, buf, sizeof(buf));
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if (bytes_to_write < 0)
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return COPY_READ_ERROR;
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if (bytes_to_write == 0)
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break;
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err = packet_write_gently(fd_out, buf, bytes_to_write);
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}
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if (!err)
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err = packet_flush_gently(fd_out);
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return err;
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}
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int write_packetized_from_buf(const char *src_in, size_t len, int fd_out)
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{
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int err = 0;
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size_t bytes_written = 0;
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size_t bytes_to_write;
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while (!err) {
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if ((len - bytes_written) > LARGE_PACKET_DATA_MAX)
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bytes_to_write = LARGE_PACKET_DATA_MAX;
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else
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bytes_to_write = len - bytes_written;
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if (bytes_to_write == 0)
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break;
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err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write);
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bytes_written += bytes_to_write;
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}
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if (!err)
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err = packet_flush_gently(fd_out);
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return err;
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}
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static int get_packet_data(int fd, char **src_buf, size_t *src_size,
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void *dst, unsigned size, int options)
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{
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ssize_t ret;
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if (fd >= 0 && src_buf && *src_buf)
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die("BUG: multiple sources given to packet_read");
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/* Read up to "size" bytes from our source, whatever it is. */
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if (src_buf && *src_buf) {
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ret = size < *src_size ? size : *src_size;
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memcpy(dst, *src_buf, ret);
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*src_buf += ret;
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*src_size -= ret;
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} else {
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ret = read_in_full(fd, dst, size);
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if (ret < 0)
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die_errno("read error");
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}
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/* And complain if we didn't get enough bytes to satisfy the read. */
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if (ret < size) {
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if (options & PACKET_READ_GENTLE_ON_EOF)
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return -1;
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die("The remote end hung up unexpectedly");
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}
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return ret;
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}
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static int packet_length(const char *linelen)
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{
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int val = hex2chr(linelen);
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return (val < 0) ? val : (val << 8) | hex2chr(linelen + 2);
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}
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int packet_read(int fd, char **src_buf, size_t *src_len,
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char *buffer, unsigned size, int options)
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{
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int len, ret;
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char linelen[4];
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ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
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if (ret < 0)
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return ret;
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len = packet_length(linelen);
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if (len < 0)
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die("protocol error: bad line length character: %.4s", linelen);
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if (!len) {
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packet_trace("0000", 4, 0);
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return 0;
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}
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len -= 4;
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if (len >= size)
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die("protocol error: bad line length %d", len);
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ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
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if (ret < 0)
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return ret;
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if ((options & PACKET_READ_CHOMP_NEWLINE) &&
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len && buffer[len-1] == '\n')
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len--;
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buffer[len] = 0;
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packet_trace(buffer, len, 0);
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return len;
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}
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static char *packet_read_line_generic(int fd,
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char **src, size_t *src_len,
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int *dst_len)
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{
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int len = packet_read(fd, src, src_len,
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packet_buffer, sizeof(packet_buffer),
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PACKET_READ_CHOMP_NEWLINE);
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if (dst_len)
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*dst_len = len;
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return len ? packet_buffer : NULL;
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}
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char *packet_read_line(int fd, int *len_p)
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{
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return packet_read_line_generic(fd, NULL, NULL, len_p);
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}
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char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
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{
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return packet_read_line_generic(-1, src, src_len, dst_len);
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}
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ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out)
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{
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int packet_len;
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size_t orig_len = sb_out->len;
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size_t orig_alloc = sb_out->alloc;
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for (;;) {
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strbuf_grow(sb_out, LARGE_PACKET_DATA_MAX);
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packet_len = packet_read(fd_in, NULL, NULL,
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/* strbuf_grow() above always allocates one extra byte to
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* store a '\0' at the end of the string. packet_read()
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* writes a '\0' extra byte at the end, too. Let it know
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* that there is already room for the extra byte.
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*/
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sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1,
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PACKET_READ_GENTLE_ON_EOF);
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if (packet_len <= 0)
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break;
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sb_out->len += packet_len;
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}
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if (packet_len < 0) {
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if (orig_alloc == 0)
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strbuf_release(sb_out);
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else
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strbuf_setlen(sb_out, orig_len);
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return packet_len;
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}
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return sb_out->len - orig_len;
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}
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