diff options
Diffstat (limited to 'pkt-line.c')
| -rw-r--r-- | pkt-line.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/pkt-line.c b/pkt-line.c new file mode 100644 index 0000000000..5a04984ea3 --- /dev/null +++ b/pkt-line.c @@ -0,0 +1,222 @@ +#include "cache.h" +#include "pkt-line.h" + +static const char *packet_trace_prefix = "git"; +static const char trace_key[] = "GIT_TRACE_PACKET"; + +void packet_trace_identity(const char *prog) +{ + packet_trace_prefix = xstrdup(prog); +} + +static void packet_trace(const char *buf, unsigned int len, int write) +{ + int i; + struct strbuf out; + + if (!trace_want(trace_key)) + return; + + /* +32 is just a guess for header + quoting */ + strbuf_init(&out, len+32); + + strbuf_addf(&out, "packet: %12s%c ", + packet_trace_prefix, write ? '>' : '<'); + + if ((len >= 4 && !prefixcmp(buf, "PACK")) || + (len >= 5 && !prefixcmp(buf+1, "PACK"))) { + strbuf_addstr(&out, "PACK ..."); + unsetenv(trace_key); + } + else { + /* XXX we should really handle printable utf8 */ + for (i = 0; i < len; i++) { + /* suppress newlines */ + if (buf[i] == '\n') + continue; + if (buf[i] >= 0x20 && buf[i] <= 0x7e) + strbuf_addch(&out, buf[i]); + else + strbuf_addf(&out, "\\%o", buf[i]); + } + } + + strbuf_addch(&out, '\n'); + trace_strbuf(trace_key, &out); + strbuf_release(&out); +} + +/* + * 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. + */ +ssize_t safe_write(int fd, const void *buf, ssize_t n) +{ + ssize_t nn = n; + while (n) { + int ret = xwrite(fd, buf, n); + if (ret > 0) { + buf = (char *) buf + ret; + n -= ret; + continue; + } + if (!ret) + die("write error (disk full?)"); + die_errno("write error"); + } + return nn; +} + +/* + * If we buffered things up above (we don't, but we should), + * we'd flush it here + */ +void packet_flush(int fd) +{ + packet_trace("0000", 4, 1); + safe_write(fd, "0000", 4); +} + +void packet_buf_flush(struct strbuf *buf) +{ + packet_trace("0000", 4, 1); + strbuf_add(buf, "0000", 4); +} + +#define hex(a) (hexchar[(a) & 15]) +static char buffer[1000]; +static unsigned format_packet(const char *fmt, va_list args) +{ + static char hexchar[] = "0123456789abcdef"; + unsigned n; + + n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args); + if (n >= sizeof(buffer)-4) + die("protocol error: impossibly long line"); + n += 4; + buffer[0] = hex(n >> 12); + buffer[1] = hex(n >> 8); + buffer[2] = hex(n >> 4); + buffer[3] = hex(n); + packet_trace(buffer+4, n-4, 1); + return n; +} + +void packet_write(int fd, const char *fmt, ...) +{ + va_list args; + unsigned n; + + va_start(args, fmt); + n = format_packet(fmt, args); + va_end(args); + safe_write(fd, buffer, n); +} + +void packet_buf_write(struct strbuf *buf, const char *fmt, ...) +{ + va_list args; + unsigned n; + + va_start(args, fmt); + n = format_packet(fmt, args); + va_end(args); + strbuf_add(buf, buffer, n); +} + +static void safe_read(int fd, void *buffer, unsigned size) +{ + ssize_t ret = read_in_full(fd, buffer, size); + if (ret < 0) + die_errno("read error"); + else if (ret < size) + die("The remote end hung up unexpectedly"); +} + +static int packet_length(const char *linelen) +{ + int n; + int len = 0; + + for (n = 0; n < 4; n++) { + unsigned char c = linelen[n]; + len <<= 4; + if (c >= '0' && c <= '9') { + len += c - '0'; + continue; + } + if (c >= 'a' && c <= 'f') { + len += c - 'a' + 10; + continue; + } + if (c >= 'A' && c <= 'F') { + len += c - 'A' + 10; + continue; + } + return -1; + } + return len; +} + +int packet_read_line(int fd, char *buffer, unsigned size) +{ + int len; + char linelen[4]; + + safe_read(fd, linelen, 4); + len = packet_length(linelen); + if (len < 0) + die("protocol error: bad line length character: %.4s", linelen); + if (!len) { + packet_trace("0000", 4, 0); + return 0; + } + len -= 4; + if (len >= size) + die("protocol error: bad line length %d", len); + safe_read(fd, buffer, len); + buffer[len] = 0; + packet_trace(buffer, len, 0); + return len; +} + +int packet_get_line(struct strbuf *out, + char **src_buf, size_t *src_len) +{ + 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; + + strbuf_add(out, *src_buf, len); + *src_buf += len; + *src_len -= len; + packet_trace(out->buf, out->len, 0); + return len; +} |