Merge branch 'maint'
[git] / sideband.c
1 #include "pkt-line.h"
2 #include "sideband.h"
3
4 /*
5  * Receive multiplexed output stream over git native protocol.
6  * in_stream is the input stream from the remote, which carries data
7  * in pkt_line format with band designator.  Demultiplex it into out
8  * and err and return error appropriately.  Band #1 carries the
9  * primary payload.  Things coming over band #2 is not necessarily
10  * error; they are usually informative message on the standard error
11  * stream, aka "verbose").  A message over band #3 is a signal that
12  * the remote died unexpectedly.  A flush() concludes the stream.
13  */
14
15 #define PREFIX "remote:"
16
17 #define ANSI_SUFFIX "\033[K"
18 #define DUMB_SUFFIX "        "
19
20 #define FIX_SIZE 10  /* large enough for any of the above */
21
22 int recv_sideband(const char *me, int in_stream, int out, int err)
23 {
24         unsigned pf = strlen(PREFIX);
25         unsigned sf;
26         char buf[LARGE_PACKET_MAX + 2*FIX_SIZE];
27         char *suffix, *term;
28         int skip_pf = 0;
29
30         memcpy(buf, PREFIX, pf);
31         term = getenv("TERM");
32         if (term && strcmp(term, "dumb"))
33                 suffix = ANSI_SUFFIX;
34         else
35                 suffix = DUMB_SUFFIX;
36         sf = strlen(suffix);
37
38         while (1) {
39                 int band, len;
40                 len = packet_read_line(in_stream, buf + pf, LARGE_PACKET_MAX);
41                 if (len == 0)
42                         break;
43                 if (len < 1) {
44                         len = sprintf(buf, "%s: protocol error: no band designator\n", me);
45                         safe_write(err, buf, len);
46                         return SIDEBAND_PROTOCOL_ERROR;
47                 }
48                 band = buf[pf] & 0xff;
49                 len--;
50                 switch (band) {
51                 case 3:
52                         buf[pf] = ' ';
53                         buf[pf+1+len] = '\n';
54                         safe_write(err, buf, pf+1+len+1);
55                         return SIDEBAND_REMOTE_ERROR;
56                 case 2:
57                         buf[pf] = ' ';
58                         do {
59                                 char *b = buf;
60                                 int brk = 0;
61
62                                 /*
63                                  * If the last buffer didn't end with a line
64                                  * break then we should not print a prefix
65                                  * this time around.
66                                  */
67                                 if (skip_pf) {
68                                         b += pf+1;
69                                 } else {
70                                         len += pf+1;
71                                         brk += pf+1;
72                                 }
73
74                                 /* Look for a line break. */
75                                 for (;;) {
76                                         brk++;
77                                         if (brk > len) {
78                                                 brk = 0;
79                                                 break;
80                                         }
81                                         if (b[brk-1] == '\n' ||
82                                             b[brk-1] == '\r')
83                                                 break;
84                                 }
85
86                                 /*
87                                  * Let's insert a suffix to clear the end
88                                  * of the screen line if a line break was
89                                  * found.  Also, if we don't skip the
90                                  * prefix, then a non-empty string must be
91                                  * present too.
92                                  */
93                                 if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
94                                         char save[FIX_SIZE];
95                                         memcpy(save, b + brk, sf);
96                                         b[brk + sf - 1] = b[brk - 1];
97                                         memcpy(b + brk - 1, suffix, sf);
98                                         safe_write(err, b, brk + sf);
99                                         memcpy(b + brk, save, sf);
100                                         len -= brk;
101                                 } else {
102                                         int l = brk ? brk : len;
103                                         safe_write(err, b, l);
104                                         len -= l;
105                                 }
106
107                                 skip_pf = !brk;
108                                 memmove(buf + pf+1, b + brk, len);
109                         } while (len);
110                         continue;
111                 case 1:
112                         safe_write(out, buf + pf+1, len);
113                         continue;
114                 default:
115                         len = sprintf(buf,
116                                       "%s: protocol error: bad band #%d\n",
117                                       me, band);
118                         safe_write(err, buf, len);
119                         return SIDEBAND_PROTOCOL_ERROR;
120                 }
121         }
122         return 0;
123 }
124
125 /*
126  * fd is connected to the remote side; send the sideband data
127  * over multiplexed packet stream.
128  */
129 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
130 {
131         ssize_t ssz = sz;
132         const char *p = data;
133
134         while (sz) {
135                 unsigned n;
136                 char hdr[5];
137
138                 n = sz;
139                 if (packet_max - 5 < n)
140                         n = packet_max - 5;
141                 sprintf(hdr, "%04x", n + 5);
142                 hdr[4] = band;
143                 safe_write(fd, hdr, 5);
144                 safe_write(fd, p, n);
145                 p += n;
146                 sz -= n;
147         }
148         return ssz;
149 }