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 const char trace_key[] = "GIT_TRACE_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_key))
  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 && !prefixcmp(buf, "PACK")) ||
  28             (len >= 5 && !prefixcmp(buf+1, "PACK"))) {
  29                 strbuf_addstr(&out, "PACK ...");
  30                 unsetenv(trace_key);
  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_key, &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 char buffer[1000];
  68 static unsigned format_packet(const char *fmt, va_list args)
  69 {
  70         static char hexchar[] = "0123456789abcdef";
  71         unsigned n;
  72
  73         n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
  74         if (n >= sizeof(buffer)-4)
  75                 die("protocol error: impossibly long line");
  76         n += 4;
  77         buffer[0] = hex(n >> 12);
  78         buffer[1] = hex(n >> 8);
  79         buffer[2] = hex(n >> 4);
  80         buffer[3] = hex(n);
  81         packet_trace(buffer+4, n-4, 1);
  82         return n;
  83 }
  84
  85 void packet_write(int fd, const char *fmt, ...)
  86 {
  87         va_list args;
  88         unsigned n;
  89
  90         va_start(args, fmt);
  91         n = format_packet(fmt, args);
  92         va_end(args);
  93         write_or_die(fd, buffer, n);
  94 }
  95
  96 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
  97 {
  98         va_list args;
  99         unsigned n;
 100
 101         va_start(args, fmt);
 102         n = format_packet(fmt, args);
 103         va_end(args);
 104         strbuf_add(buf, buffer, n);
 105 }
 106
 107 static int get_packet_data(int fd, char **src_buf, size_t *src_size,
 108                            void *dst, unsigned size, int options)
 109 {
 110         ssize_t ret;
 111
 112         if (fd >= 0 && src_buf && *src_buf)
 113                 die("BUG: multiple sources given to packet_read");
 114
 115         /* Read up to "size" bytes from our source, whatever it is. */
 116         if (src_buf && *src_buf) {
 117                 ret = size < *src_size ? size : *src_size;
 118                 memcpy(dst, *src_buf, ret);
 119                 *src_buf += ret;
 120                 *src_size -= ret;
 121         } else {
 122                 ret = read_in_full(fd, dst, size);
 123                 if (ret < 0)
 124                         die_errno("read error");
 125         }
 126
 127         /* And complain if we didn't get enough bytes to satisfy the read. */
 128         if (ret < size) {
 129                 if (options & PACKET_READ_GENTLE_ON_EOF)
 130                         return -1;
 131
 132                 die("The remote end hung up unexpectedly");
 133         }
 134
 135         return ret;
 136 }
 137
 138 static int packet_length(const char *linelen)
 139 {
 140         int n;
 141         int len = 0;
 142
 143         for (n = 0; n < 4; n++) {
 144                 unsigned char c = linelen[n];
 145                 len <<= 4;
 146                 if (c >= '0' && c <= '9') {
 147                         len += c - '0';
 148                         continue;
 149                 }
 150                 if (c >= 'a' && c <= 'f') {
 151                         len += c - 'a' + 10;
 152                         continue;
 153                 }
 154                 if (c >= 'A' && c <= 'F') {
 155                         len += c - 'A' + 10;
 156                         continue;
 157                 }
 158                 return -1;
 159         }
 160         return len;
 161 }
 162
 163 int packet_read(int fd, char **src_buf, size_t *src_len,
 164                 char *buffer, unsigned size, int options)
 165 {
 166         int len, ret;
 167         char linelen[4];
 168
 169         ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
 170         if (ret < 0)
 171                 return ret;
 172         len = packet_length(linelen);
 173         if (len < 0)
 174                 die("protocol error: bad line length character: %.4s", linelen);
 175         if (!len) {
 176                 packet_trace("0000", 4, 0);
 177                 return 0;
 178         }
 179         len -= 4;
 180         if (len >= size)
 181                 die("protocol error: bad line length %d", len);
 182         ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
 183         if (ret < 0)
 184                 return ret;
 185
 186         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 187             len && buffer[len-1] == '\n')
 188                 len--;
 189
 190         buffer[len] = 0;
 191         packet_trace(buffer, len, 0);
 192         return len;
 193 }
 194
 195 static char *packet_read_line_generic(int fd,
 196                                       char **src, size_t *src_len,
 197                                       int *dst_len)
 198 {
 199         int len = packet_read(fd, src, src_len,
 200                               packet_buffer, sizeof(packet_buffer),
 201                               PACKET_READ_CHOMP_NEWLINE);
 202         if (dst_len)
 203                 *dst_len = len;
 204         return len ? packet_buffer : NULL;
 205 }
 206
 207 char *packet_read_line(int fd, int *len_p)
 208 {
 209         return packet_read_line_generic(fd, NULL, NULL, len_p);
 210 }
 211
 212 char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
 213 {
 214         return packet_read_line_generic(-1, src, src_len, dst_len);
 215 }