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 ssize_t safe_write(int fd, const void *buf, ssize_t n)
  50 {
  51         ssize_t nn = n;
  52         while (n) {
  53                 int ret = xwrite(fd, buf, n);
  54                 if (ret > 0) {
  55                         buf = (char *) buf + ret;
  56                         n -= ret;
  57                         continue;
  58                 }
  59                 if (!ret)
  60                         die("write error (disk full?)");
  61                 die_errno("write error");
  62         }
  63         return nn;
  64 }
  65
  66 /*
  67  * If we buffered things up above (we don't, but we should),
  68  * we'd flush it here
  69  */
  70 void packet_flush(int fd)
  71 {
  72         packet_trace("0000", 4, 1);
  73         safe_write(fd, "0000", 4);
  74 }
  75
  76 void packet_buf_flush(struct strbuf *buf)
  77 {
  78         packet_trace("0000", 4, 1);
  79         strbuf_add(buf, "0000", 4);
  80 }
  81
  82 #define hex(a) (hexchar[(a) & 15])
  83 static char buffer[1000];
  84 static unsigned format_packet(const char *fmt, va_list args)
  85 {
  86         static char hexchar[] = "0123456789abcdef";
  87         unsigned n;
  88
  89         n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
  90         if (n >= sizeof(buffer)-4)
  91                 die("protocol error: impossibly long line");
  92         n += 4;
  93         buffer[0] = hex(n >> 12);
  94         buffer[1] = hex(n >> 8);
  95         buffer[2] = hex(n >> 4);
  96         buffer[3] = hex(n);
  97         packet_trace(buffer+4, n-4, 1);
  98         return n;
  99 }
 100
 101 void packet_write(int fd, const char *fmt, ...)
 102 {
 103         va_list args;
 104         unsigned n;
 105
 106         va_start(args, fmt);
 107         n = format_packet(fmt, args);
 108         va_end(args);
 109         safe_write(fd, buffer, n);
 110 }
 111
 112 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
 113 {
 114         va_list args;
 115         unsigned n;
 116
 117         va_start(args, fmt);
 118         n = format_packet(fmt, args);
 119         va_end(args);
 120         strbuf_add(buf, buffer, n);
 121 }
 122
 123 static int safe_read(int fd, void *buffer, unsigned size, int return_line_fail)
 124 {
 125         ssize_t ret = read_in_full(fd, buffer, size);
 126         if (ret < 0)
 127                 die_errno("read error");
 128         else if (ret < size) {
 129                 if (return_line_fail)
 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 static int packet_read_internal(int fd, char *buffer, unsigned size, int return_line_fail)
 164 {
 165         int len, ret;
 166         char linelen[4];
 167
 168         ret = safe_read(fd, linelen, 4, return_line_fail);
 169         if (return_line_fail && ret < 0)
 170                 return ret;
 171         len = packet_length(linelen);
 172         if (len < 0)
 173                 die("protocol error: bad line length character: %.4s", linelen);
 174         if (!len) {
 175                 packet_trace("0000", 4, 0);
 176                 return 0;
 177         }
 178         len -= 4;
 179         if (len >= size)
 180                 die("protocol error: bad line length %d", len);
 181         ret = safe_read(fd, buffer, len, return_line_fail);
 182         if (return_line_fail && ret < 0)
 183                 return ret;
 184         buffer[len] = 0;
 185         packet_trace(buffer, len, 0);
 186         return len;
 187 }
 188
 189 int packet_read(int fd, char *buffer, unsigned size)
 190 {
 191         return packet_read_internal(fd, buffer, size, 1);
 192 }
 193
 194 int packet_read_line(int fd, char *buffer, unsigned size)
 195 {
 196         return packet_read_internal(fd, buffer, size, 0);
 197 }
 198
 199 int packet_get_line(struct strbuf *out,
 200         char **src_buf, size_t *src_len)
 201 {
 202         int len;
 203
 204         if (*src_len < 4)
 205                 return -1;
 206         len = packet_length(*src_buf);
 207         if (len < 0)
 208                 return -1;
 209         if (!len) {
 210                 *src_buf += 4;
 211                 *src_len -= 4;
 212                 packet_trace("0000", 4, 0);
 213                 return 0;
 214         }
 215         if (*src_len < len)
 216                 return -2;
 217
 218         *src_buf += 4;
 219         *src_len -= 4;
 220         len -= 4;
 221
 222         strbuf_add(out, *src_buf, len);
 223         *src_buf += len;
 224         *src_len -= len;
 225         packet_trace(out->buf, out->len, 0);
 226         return len;
 227 }