http-push: fix check condition on http.c::finish_http_pack_request()
[git/git.git] / pkt-line.c
CommitLineData
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1#include "cache.h"
2#include "pkt-line.h"
3
4/*
5 * Write a packetized stream, where each line is preceded by
6 * its length (including the header) as a 4-byte hex number.
7 * A length of 'zero' means end of stream (and a length of 1-3
a6080a0a 8 * would be an error).
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9 *
10 * This is all pretty stupid, but we use this packetized line
11 * format to make a streaming format possible without ever
12 * over-running the read buffers. That way we'll never read
13 * into what might be the pack data (which should go to another
14 * process entirely).
15 *
16 * The writing side could use stdio, but since the reading
17 * side can't, we stay with pure read/write interfaces.
18 */
583b7ea3 19ssize_t safe_write(int fd, const void *buf, ssize_t n)
f3a3214e 20{
583b7ea3 21 ssize_t nn = n;
f3a3214e 22 while (n) {
1c15afb9 23 int ret = xwrite(fd, buf, n);
f3a3214e 24 if (ret > 0) {
1d7f171c 25 buf = (char *) buf + ret;
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26 n -= ret;
27 continue;
28 }
29 if (!ret)
30 die("write error (disk full?)");
d824cbba 31 die_errno("write error");
f3a3214e 32 }
583b7ea3 33 return nn;
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34}
35
36/*
37 * If we buffered things up above (we don't, but we should),
38 * we'd flush it here
39 */
40void packet_flush(int fd)
41{
42 safe_write(fd, "0000", 4);
43}
44
45#define hex(a) (hexchar[(a) & 15])
46void packet_write(int fd, const char *fmt, ...)
47{
48 static char buffer[1000];
49 static char hexchar[] = "0123456789abcdef";
50 va_list args;
51 unsigned n;
52
53 va_start(args, fmt);
54 n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
55 va_end(args);
56 if (n >= sizeof(buffer)-4)
57 die("protocol error: impossibly long line");
58 n += 4;
59 buffer[0] = hex(n >> 12);
60 buffer[1] = hex(n >> 8);
61 buffer[2] = hex(n >> 4);
62 buffer[3] = hex(n);
63 safe_write(fd, buffer, n);
64}
65
66static void safe_read(int fd, void *buffer, unsigned size)
67{
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68 ssize_t ret = read_in_full(fd, buffer, size);
69 if (ret < 0)
d824cbba 70 die_errno("read error");
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71 else if (ret < size)
72 die("The remote end hung up unexpectedly");
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73}
74
75int packet_read_line(int fd, char *buffer, unsigned size)
76{
77 int n;
78 unsigned len;
79 char linelen[4];
80
81 safe_read(fd, linelen, 4);
82
83 len = 0;
84 for (n = 0; n < 4; n++) {
85 unsigned char c = linelen[n];
86 len <<= 4;
87 if (c >= '0' && c <= '9') {
88 len += c - '0';
89 continue;
90 }
91 if (c >= 'a' && c <= 'f') {
92 len += c - 'a' + 10;
93 continue;
94 }
95 if (c >= 'A' && c <= 'F') {
96 len += c - 'A' + 10;
97 continue;
98 }
99 die("protocol error: bad line length character");
100 }
101 if (!len)
102 return 0;
103 len -= 4;
104 if (len >= size)
105 die("protocol error: bad line length %d", len);
106 safe_read(fd, buffer, len);
107 buffer[len] = 0;
108 return len;
109}