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 safe_read(int fd, void *buffer, unsigned size, int options)
 108 {
 109         ssize_t ret = read_in_full(fd, buffer, size);
 110         if (ret < 0)
 111                 die_errno("read error");
 112         else if (ret < size) {
 113                 if (options & PACKET_READ_GENTLE_ON_EOF)
 114                         return -1;
 115
 116                 die("The remote end hung up unexpectedly");
 117         }
 118
 119         return ret;
 120 }
 121
 122 static int packet_length(const char *linelen)
 123 {
 124         int n;
 125         int len = 0;
 126
 127         for (n = 0; n < 4; n++) {
 128                 unsigned char c = linelen[n];
 129                 len <<= 4;
 130                 if (c >= '0' && c <= '9') {
 131                         len += c - '0';
 132                         continue;
 133                 }
 134                 if (c >= 'a' && c <= 'f') {
 135                         len += c - 'a' + 10;
 136                         continue;
 137                 }
 138                 if (c >= 'A' && c <= 'F') {
 139                         len += c - 'A' + 10;
 140                         continue;
 141                 }
 142                 return -1;
 143         }
 144         return len;
 145 }
 146
 147 int packet_read(int fd, char *buffer, unsigned size, int options)
 148 {
 149         int len, ret;
 150         char linelen[4];
 151
 152         ret = safe_read(fd, linelen, 4, options);
 153         if (ret < 0)
 154                 return ret;
 155         len = packet_length(linelen);
 156         if (len < 0)
 157                 die("protocol error: bad line length character: %.4s", linelen);
 158         if (!len) {
 159                 packet_trace("0000", 4, 0);
 160                 return 0;
 161         }
 162         len -= 4;
 163         if (len >= size)
 164                 die("protocol error: bad line length %d", len);
 165         ret = safe_read(fd, buffer, len, options);
 166         if (ret < 0)
 167                 return ret;
 168
 169         if ((options & PACKET_READ_CHOMP_NEWLINE) &&
 170             len && buffer[len-1] == '\n')
 171                 len--;
 172
 173         buffer[len] = 0;
 174         packet_trace(buffer, len, 0);
 175         return len;
 176 }
 177
 178 char *packet_read_line(int fd, int *len_p)
 179 {
 180         int len = packet_read(fd, packet_buffer, sizeof(packet_buffer),
 181                               PACKET_READ_CHOMP_NEWLINE);
 182         if (len_p)
 183                 *len_p = len;
 184         return len ? packet_buffer : NULL;
 185 }
 186
 187 int packet_get_line(struct strbuf *out,
 188         char **src_buf, size_t *src_len)
 189 {
 190         int len;
 191
 192         if (*src_len < 4)
 193                 return -1;
 194         len = packet_length(*src_buf);
 195         if (len < 0)
 196                 return -1;
 197         if (!len) {
 198                 *src_buf += 4;
 199                 *src_len -= 4;
 200                 packet_trace("0000", 4, 0);
 201                 return 0;
 202         }
 203         if (*src_len < len)
 204                 return -2;
 205
 206         *src_buf += 4;
 207         *src_len -= 4;
 208         len -= 4;
 209
 210         strbuf_add(out, *src_buf, len);
 211         *src_buf += len;
 212         *src_len -= len;
 213         packet_trace(out->buf, out->len, 0);
 214         return len;
 215 }