pkt-line.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3
   4 char packet_buffer[LARGE_PACKET_MAX];
   5 static const char *packet_trace_prefix = "git";
   6 static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
   7
   8 void packet_trace_identity(const char *prog)
   9 {
  10         packet_trace_prefix = xstrdup(prog);
  11 }
  12
  13 static void packet_trace(const char *buf, unsigned int len, int write)
  14 {
  15         int i;
  16         struct strbuf out;
  17
  18         if (!trace_want(&trace_packet))
  19                 return;
  20
  21         /* +32 is just a guess for header + quoting */
  22         strbuf_init(&out, len+32);
  23
  24         strbuf_addf(&out, "packet: %12s%c ",
  25                     packet_trace_prefix, write ? '>' : '<');
  26
  27         if ((len >= 4 && starts_with(buf, "PACK")) ||
  28             (len >= 5 && starts_with(buf+1, "PACK"))) {
  29                 strbuf_addstr(&out, "PACK ...");
  30                 trace_disable(&trace_packet);
  31         }
  32         else {
  33                 /* XXX we should really handle printable utf8 */
  34                 for (i = 0; i < len; i++) {
  35                         /* suppress newlines */
  36                         if (buf[i] == '\n')
  37                                 continue;
  38                         if (buf[i] >= 0x20 && buf[i] <= 0x7e)
  39                                 strbuf_addch(&out, buf[i]);
  40                         else
  41                                 strbuf_addf(&out, "\\%o", buf[i]);
  42                 }
  43         }
  44
  45         strbuf_addch(&out, '\n');
  46         trace_strbuf(&trace_packet, &out);
  47         strbuf_release(&out);
  48 }
  49
  50 /*
  51  * If we buffered things up above (we don't, but we should),
  52  * we'd flush it here
  53  */
  54 void packet_flush(int fd)
  55 {
  56         packet_trace("0000", 4, 1);
  57         write_or_die(fd, "0000", 4);
  58 }
  59
  60 void packet_buf_flush(struct strbuf *buf)
  61 {
  62         packet_trace("0000", 4, 1);
  63         strbuf_add(buf, "0000", 4);
  64 }
  65
  66 #define hex(a) (hexchar[(a) & 15])
  67 static void format_packet(struct strbuf *out, const char *fmt, va_list args)
  68 {
  69         static char hexchar[] = "0123456789abcdef";
  70         size_t orig_len, n;
  71
  72         orig_len = out->len;
  73         strbuf_addstr(out, "0000");
  74         strbuf_vaddf(out, fmt, args);
  75         n = out->len - orig_len;
  76
  77         if (n > LARGE_PACKET_MAX)
  78                 die("protocol error: impossibly long line");
  79
  80         out->buf[orig_len + 0] = hex(n >> 12);
  81         out->buf[orig_len + 1] = hex(n >> 8);
  82         out->buf[orig_len + 2] = hex(n >> 4);
  83         out->buf[orig_len + 3] = hex(n);
  84         packet_trace(out->buf + orig_len + 4, n - 4, 1);
  85 }
  86
  87 void packet_write(int fd, const char *fmt, ...)
  88 {
  89         static struct strbuf buf = STRBUF_INIT;
  90         va_list args;
  91
  92         strbuf_reset(&buf);
  93         va_start(args, fmt);
  94         format_packet(&buf, fmt, args);
  95         va_end(args);
  96         write_or_die(fd, buf.buf, buf.len);
  97 }
  98
  99 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 100 {
 101         va_list args;
 102
 103         va_start(args, fmt);
 104         format_packet(buf, fmt, args);
 105         va_end(args);
 106 }
 107
 108 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 109                            void *dst, unsigned size, int options)
 110 {
 111         ssize_t ret;
 112
 113         if (fd >= 0 && src_buf && *src_buf)
 114                 die("BUG: multiple sources given to packet_read");
 115
 116         /* Read up to "size" bytes from our source, whatever it is. */
 117         if (src_buf && *src_buf) {
 118                 ret = size < *src_size ? size : *src_size;
 119                 memcpy(dst, *src_buf, ret);
 120                 *src_buf += ret;
 121                 *src_size -= ret;
 122         } else {
 123                 ret = read_in_full(fd, dst, size);
 124                 if (ret < 0)
 125                         die_errno("read error");
 126         }
 127
 128         /* And complain if we didn't get enough bytes to satisfy the read. */
 129         if (ret < size) {
 130                 if (options & PACKET_READ_GENTLE_ON_EOF)
 131                         return -1;
 132
 133                 die("The remote end hung up unexpectedly");
 134         }
 135
 136         return ret;
 137 }
 138
 139 static int packet_length(const char *linelen)
 140 {
 141         int n;
 142         int len = 0;
 143
 144         for (n = 0; n < 4; n++) {
 145                 unsigned char c = linelen[n];
 146                 len <<= 4;
 147                 if (c >= '0' && c <= '9') {
 148                         len += c - '0';
 149                         continue;
 150                 }
 151                 if (c >= 'a' && c <= 'f') {
 152                         len += c - 'a' + 10;
 153                         continue;
 154                 }
 155                 if (c >= 'A' && c <= 'F') {
 156                         len += c - 'A' + 10;
 157                         continue;
 158                 }
 159                 return -1;
 160         }
 161         return len;
 162 }
 163
 164 int packet_read(int fd, char **src_buf, size_t *src_len,
 165                 char *buffer, unsigned size, int options)
 166 {
 167         int len, ret;
 168         char linelen[4];
 169
 170         ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
 171         if (ret < 0)
 172                 return ret;
 173         len = packet_length(linelen);
 174         if (len < 0)
 175                 die("protocol error: bad line length character: %.4s", linelen);
 176         if (!len) {
 177                 packet_trace("0000", 4, 0);
 178                 return 0;
 179         }
 180         len -= 4;
 181         if (len >= size)
 182                 die("protocol error: bad line length %d", len);
 183         ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
 184         if (ret < 0)
 185                 return ret;
 186
 187         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 188             len && buffer[len-1] == '\n')
 189                 len--;
 190
 191         buffer[len] = 0;
 192         packet_trace(buffer, len, 0);
 193         return len;
 194 }
 195
 196 static char *packet_read_line_generic(int fd,
 197                                       char **src, size_t *src_len,
 198                                       int *dst_len)
 199 {
 200         int len = packet_read(fd, src, src_len,
 201                               packet_buffer, sizeof(packet_buffer),
 202                               PACKET_READ_CHOMP_NEWLINE);
 203         if (dst_len)
 204                 *dst_len = len;
 205         return len ? packet_buffer : NULL;
 206 }
 207
 208 char *packet_read_line(int fd, int *len_p)
 209 {
 210         return packet_read_line_generic(fd, NULL, NULL, len_p);
 211 }
 212
 213 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 214 {
 215         return packet_read_line_generic(-1, src, src_len, dst_len);
 216 }