5138f47b645325592b3403b48b2282b94b5269d7
   1#include "cache.h"
   2#include "pkt-line.h"
   3
   4static const char *packet_trace_prefix = "git";
   5static const char trace_key[] = "GIT_TRACE_PACKET";
   6
   7void packet_trace_identity(const char *prog)
   8{
   9        packet_trace_prefix = xstrdup(prog);
  10}
  11
  12static 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
  49ssize_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 */
  70void packet_flush(int fd)
  71{
  72        packet_trace("0000", 4, 1);
  73        safe_write(fd, "0000", 4);
  74}
  75
  76void 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])
  83static char buffer[1000];
  84static 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
 101void 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
 112void 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
 123static 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
 138static 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
 163static 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
 189int packet_read(int fd, char *buffer, unsigned size)
 190{
 191        return packet_read_internal(fd, buffer, size, 1);
 192}
 193
 194int packet_read_line(int fd, char *buffer, unsigned size)
 195{
 196        return packet_read_internal(fd, buffer, size, 0);
 197}
 198
 199int 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}