pkt-line.c

   1 #include "cache.h"
   2 #include "pkt-line.h"
   3
   4 static const char *packet_trace_prefix = "git";
   5 static const char trace_key[] = "GIT_TRACE_PACKET";
   6
   7 void packet_trace_identity(const char *prog)
   8 {
   9         packet_trace_prefix = xstrdup(prog);
  10 }
  11
  12 static void packet_trace(const char *buf, unsigned int len, int write)
  13 {
  14         int i;
  15         struct strbuf out;
  16
  17         if (!trace_want(trace_key))
  18                 return;
  19
  20         /* +32 is just a guess for header + quoting */
  21         strbuf_init(&out, len+32);
  22
  23         strbuf_addf(&out, "packet: %12s%c ",
  24                     packet_trace_prefix, write ? '>' : '<');
  25
  26         if ((len >= 4 && !prefixcmp(buf, "PACK")) ||
  27             (len >= 5 && !prefixcmp(buf+1, "PACK"))) {
  28                 strbuf_addstr(&out, "PACK ...");
  29                 unsetenv(trace_key);
  30         }
  31         else {
  32                 /* XXX we should really handle printable utf8 */
  33                 for (i = 0; i < len; i++) {
  34                         /* suppress newlines */
  35                         if (buf[i] == '\n')
  36                                 continue;
  37                         if (buf[i] >= 0x20 && buf[i] <= 0x7e)
  38                                 strbuf_addch(&out, buf[i]);
  39                         else
  40                                 strbuf_addf(&out, "\\%o", buf[i]);
  41                 }
  42         }
  43
  44         strbuf_addch(&out, '\n');
  45         trace_strbuf(trace_key, &out);
  46         strbuf_release(&out);
  47 }
  48
  49 /*
  50  * If we buffered things up above (we don't, but we should),
  51  * we'd flush it here
  52  */
  53 void packet_flush(int fd)
  54 {
  55         packet_trace("0000", 4, 1);
  56         write_or_die(fd, "0000", 4);
  57 }
  58
  59 void packet_buf_flush(struct strbuf *buf)
  60 {
  61         packet_trace("0000", 4, 1);
  62         strbuf_add(buf, "0000", 4);
  63 }
  64
  65 #define hex(a) (hexchar[(a) & 15])
  66 static char buffer[1000];
  67 static unsigned format_packet(const char *fmt, va_list args)
  68 {
  69         static char hexchar[] = "0123456789abcdef";
  70         unsigned n;
  71
  72         n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
  73         if (n >= sizeof(buffer)-4)
  74                 die("protocol error: impossibly long line");
  75         n += 4;
  76         buffer[0] = hex(n >> 12);
  77         buffer[1] = hex(n >> 8);
  78         buffer[2] = hex(n >> 4);
  79         buffer[3] = hex(n);
  80         packet_trace(buffer+4, n-4, 1);
  81         return n;
  82 }
  83
  84 void packet_write(int fd, const char *fmt, ...)
  85 {
  86         va_list args;
  87         unsigned n;
  88
  89         va_start(args, fmt);
  90         n = format_packet(fmt, args);
  91         va_end(args);
  92         write_or_die(fd, buffer, n);
  93 }
  94
  95 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
  96 {
  97         va_list args;
  98         unsigned n;
  99
 100         va_start(args, fmt);
 101         n = format_packet(fmt, args);
 102         va_end(args);
 103         strbuf_add(buf, buffer, n);
 104 }
 105
 106 static int safe_read(int fd, void *buffer, unsigned size, int options)
 107 {
 108         ssize_t ret = read_in_full(fd, buffer, size);
 109         if (ret < 0)
 110                 die_errno("read error");
 111         else if (ret < size) {
 112                 if (options & PACKET_READ_GENTLE_ON_EOF)
 113                         return -1;
 114
 115                 die("The remote end hung up unexpectedly");
 116         }
 117
 118         return ret;
 119 }
 120
 121 static int packet_length(const char *linelen)
 122 {
 123         int n;
 124         int len = 0;
 125
 126         for (n = 0; n < 4; n++) {
 127                 unsigned char c = linelen[n];
 128                 len <<= 4;
 129                 if (c >= '0' && c <= '9') {
 130                         len += c - '0';
 131                         continue;
 132                 }
 133                 if (c >= 'a' && c <= 'f') {
 134                         len += c - 'a' + 10;
 135                         continue;
 136                 }
 137                 if (c >= 'A' && c <= 'F') {
 138                         len += c - 'A' + 10;
 139                         continue;
 140                 }
 141                 return -1;
 142         }
 143         return len;
 144 }
 145
 146 int packet_read(int fd, char *buffer, unsigned size, int options)
 147 {
 148         int len, ret;
 149         char linelen[4];
 150
 151         ret = safe_read(fd, linelen, 4, options);
 152         if (ret < 0)
 153                 return ret;
 154         len = packet_length(linelen);
 155         if (len < 0)
 156                 die("protocol error: bad line length character: %.4s", linelen);
 157         if (!len) {
 158                 packet_trace("0000", 4, 0);
 159                 return 0;
 160         }
 161         len -= 4;
 162         if (len >= size)
 163                 die("protocol error: bad line length %d", len);
 164         ret = safe_read(fd, buffer, len, options);
 165         if (ret < 0)
 166                 return ret;
 167
 168         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 169             len && buffer[len-1] == '\n')
 170                 len--;
 171
 172         buffer[len] = 0;
 173         packet_trace(buffer, len, 0);
 174         return len;
 175 }
 176
 177 int packet_read_line(int fd, char *buffer, unsigned size)
 178 {
 179         return packet_read(fd, buffer, size, PACKET_READ_CHOMP_NEWLINE);
 180 }
 181
 182 int packet_get_line(struct strbuf *out,
 183         char **src_buf, size_t *src_len)
 184 {
 185         int len;
 186
 187         if (*src_len < 4)
 188                 return -1;
 189         len = packet_length(*src_buf);
 190         if (len < 0)
 191                 return -1;
 192         if (!len) {
 193                 *src_buf += 4;
 194                 *src_len -= 4;
 195                 packet_trace("0000", 4, 0);
 196                 return 0;
 197         }
 198         if (*src_len < len)
 199                 return -2;
 200
 201         *src_buf += 4;
 202         *src_len -= 4;
 203         len -= 4;
 204
 205         strbuf_add(out, *src_buf, len);
 206         *src_buf += len;
 207         *src_len -= len;
 208         packet_trace(out->buf, out->len, 0);
 209         return len;
 210 }