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 static struct trace_key trace_pack = TRACE_KEY_INIT(PACKFILE);
   8
   9 void packet_trace_identity(const char *prog)
  10 {
  11         packet_trace_prefix = xstrdup(prog);
  12 }
  13
  14 static int packet_trace_pack(const char *buf, unsigned int len, int sideband)
  15 {
  16         if (!sideband) {
  17                 trace_verbatim(&trace_pack, buf, len);
  18                 return 1;
  19         } else if (len && *buf == '\1') {
  20                 trace_verbatim(&trace_pack, buf + 1, len - 1);
  21                 return 1;
  22         } else {
  23                 /* it's another non-pack sideband */
  24                 return 0;
  25         }
  26 }
  27
  28 static void packet_trace(const char *buf, unsigned int len, int write)
  29 {
  30         int i;
  31         struct strbuf out;
  32         static int in_pack, sideband;
  33
  34         if (!trace_want(&trace_packet) && !trace_want(&trace_pack))
  35                 return;
  36
  37         if (in_pack) {
  38                 if (packet_trace_pack(buf, len, sideband))
  39                         return;
  40         } else if (starts_with(buf, "PACK") || starts_with(buf, "\1PACK")) {
  41                 in_pack = 1;
  42                 sideband = *buf == '\1';
  43                 packet_trace_pack(buf, len, sideband);
  44
  45                 /*
  46                  * Make a note in the human-readable trace that the pack data
  47                  * started.
  48                  */
  49                 buf = "PACK ...";
  50                 len = strlen(buf);
  51         }
  52
  53         if (!trace_want(&trace_packet))
  54                 return;
  55
  56         /* +32 is just a guess for header + quoting */
  57         strbuf_init(&out, len+32);
  58
  59         strbuf_addf(&out, "packet: %12s%c ",
  60                     packet_trace_prefix, write ? '>' : '<');
  61
  62         /* XXX we should really handle printable utf8 */
  63         for (i = 0; i < len; i++) {
  64                 /* suppress newlines */
  65                 if (buf[i] == '\n')
  66                         continue;
  67                 if (buf[i] >= 0x20 && buf[i] <= 0x7e)
  68                         strbuf_addch(&out, buf[i]);
  69                 else
  70                         strbuf_addf(&out, "\\%o", buf[i]);
  71         }
  72
  73         strbuf_addch(&out, '\n');
  74         trace_strbuf(&trace_packet, &out);
  75         strbuf_release(&out);
  76 }
  77
  78 /*
  79  * If we buffered things up above (we don't, but we should),
  80  * we'd flush it here
  81  */
  82 void packet_flush(int fd)
  83 {
  84         packet_trace("0000", 4, 1);
  85         write_or_die(fd, "0000", 4);
  86 }
  87
  88 void packet_buf_flush(struct strbuf *buf)
  89 {
  90         packet_trace("0000", 4, 1);
  91         strbuf_add(buf, "0000", 4);
  92 }
  93
  94 #define hex(a) (hexchar[(a) & 15])
  95 static void format_packet(struct strbuf *out, const char *fmt, va_list args)
  96 {
  97         static char hexchar[] = "0123456789abcdef";
  98         size_t orig_len, n;
  99
 100         orig_len = out->len;
 101         strbuf_addstr(out, "0000");
 102         strbuf_vaddf(out, fmt, args);
 103         n = out->len - orig_len;
 104
 105         if (n > LARGE_PACKET_MAX)
 106                 die("protocol error: impossibly long line");
 107
 108         out->buf[orig_len + 0] = hex(n >> 12);
 109         out->buf[orig_len + 1] = hex(n >> 8);
 110         out->buf[orig_len + 2] = hex(n >> 4);
 111         out->buf[orig_len + 3] = hex(n);
 112         packet_trace(out->buf + orig_len + 4, n - 4, 1);
 113 }
 114
 115 void packet_write(int fd, const char *fmt, ...)
 116 {
 117         static struct strbuf buf = STRBUF_INIT;
 118         va_list args;
 119
 120         strbuf_reset(&buf);
 121         va_start(args, fmt);
 122         format_packet(&buf, fmt, args);
 123         va_end(args);
 124         write_or_die(fd, buf.buf, buf.len);
 125 }
 126
 127 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 128 {
 129         va_list args;
 130
 131         va_start(args, fmt);
 132         format_packet(buf, fmt, args);
 133         va_end(args);
 134 }
 135
 136 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 137                            void *dst, unsigned size, int options)
 138 {
 139         ssize_t ret;
 140
 141         if (fd >= 0 && src_buf && *src_buf)
 142                 die("BUG: multiple sources given to packet_read");
 143
 144         /* Read up to "size" bytes from our source, whatever it is. */
 145         if (src_buf && *src_buf) {
 146                 ret = size < *src_size ? size : *src_size;
 147                 memcpy(dst, *src_buf, ret);
 148                 *src_buf += ret;
 149                 *src_size -= ret;
 150         } else {
 151                 ret = read_in_full(fd, dst, size);
 152                 if (ret < 0)
 153                         die_errno("read error");
 154         }
 155
 156         /* And complain if we didn't get enough bytes to satisfy the read. */
 157         if (ret < size) {
 158                 if (options & PACKET_READ_GENTLE_ON_EOF)
 159                         return -1;
 160
 161                 die("The remote end hung up unexpectedly");
 162         }
 163
 164         return ret;
 165 }
 166
 167 static int packet_length(const char *linelen)
 168 {
 169         int n;
 170         int len = 0;
 171
 172         for (n = 0; n < 4; n++) {
 173                 unsigned char c = linelen[n];
 174                 len <<= 4;
 175                 if (c >= '0' && c <= '9') {
 176                         len += c - '0';
 177                         continue;
 178                 }
 179                 if (c >= 'a' && c <= 'f') {
 180                         len += c - 'a' + 10;
 181                         continue;
 182                 }
 183                 if (c >= 'A' && c <= 'F') {
 184                         len += c - 'A' + 10;
 185                         continue;
 186                 }
 187                 return -1;
 188         }
 189         return len;
 190 }
 191
 192 int packet_read(int fd, char **src_buf, size_t *src_len,
 193                 char *buffer, unsigned size, int options)
 194 {
 195         int len, ret;
 196         char linelen[4];
 197
 198         ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
 199         if (ret < 0)
 200                 return ret;
 201         len = packet_length(linelen);
 202         if (len < 0)
 203                 die("protocol error: bad line length character: %.4s", linelen);
 204         if (!len) {
 205                 packet_trace("0000", 4, 0);
 206                 return 0;
 207         }
 208         len -= 4;
 209         if (len >= size)
 210                 die("protocol error: bad line length %d", len);
 211         ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
 212         if (ret < 0)
 213                 return ret;
 214
 215         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 216             len && buffer[len-1] == '\n')
 217                 len--;
 218
 219         buffer[len] = 0;
 220         packet_trace(buffer, len, 0);
 221         return len;
 222 }
 223
 224 static char *packet_read_line_generic(int fd,
 225                                       char **src, size_t *src_len,
 226                                       int *dst_len)
 227 {
 228         int len = packet_read(fd, src, src_len,
 229                               packet_buffer, sizeof(packet_buffer),
 230                               PACKET_READ_CHOMP_NEWLINE);
 231         if (dst_len)
 232                 *dst_len = len;
 233         return len ? packet_buffer : NULL;
 234 }
 235
 236 char *packet_read_line(int fd, int *len_p)
 237 {
 238         return packet_read_line_generic(fd, NULL, NULL, len_p);
 239 }
 240
 241 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 242 {
 243         return packet_read_line_generic(-1, src, src_len, dst_len);
 244 }