sparse: Fix errors and silence warnings
[git/git.git] / 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 /*
50 * Write a packetized stream, where each line is preceded by
51 * its length (including the header) as a 4-byte hex number.
52 * A length of 'zero' means end of stream (and a length of 1-3
53 * would be an error).
54 *
55 * This is all pretty stupid, but we use this packetized line
56 * format to make a streaming format possible without ever
57 * over-running the read buffers. That way we'll never read
58 * into what might be the pack data (which should go to another
59 * process entirely).
60 *
61 * The writing side could use stdio, but since the reading
62 * side can't, we stay with pure read/write interfaces.
63 */
64 ssize_t safe_write(int fd, const void *buf, ssize_t n)
65 {
66 ssize_t nn = n;
67 while (n) {
68 int ret = xwrite(fd, buf, n);
69 if (ret > 0) {
70 buf = (char *) buf + ret;
71 n -= ret;
72 continue;
73 }
74 if (!ret)
75 die("write error (disk full?)");
76 die_errno("write error");
77 }
78 return nn;
79 }
80
81 /*
82 * If we buffered things up above (we don't, but we should),
83 * we'd flush it here
84 */
85 void packet_flush(int fd)
86 {
87 packet_trace("0000", 4, 1);
88 safe_write(fd, "0000", 4);
89 }
90
91 void packet_buf_flush(struct strbuf *buf)
92 {
93 packet_trace("0000", 4, 1);
94 strbuf_add(buf, "0000", 4);
95 }
96
97 #define hex(a) (hexchar[(a) & 15])
98 static char buffer[1000];
99 static unsigned format_packet(const char *fmt, va_list args)
100 {
101 static char hexchar[] = "0123456789abcdef";
102 unsigned n;
103
104 n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
105 if (n >= sizeof(buffer)-4)
106 die("protocol error: impossibly long line");
107 n += 4;
108 buffer[0] = hex(n >> 12);
109 buffer[1] = hex(n >> 8);
110 buffer[2] = hex(n >> 4);
111 buffer[3] = hex(n);
112 packet_trace(buffer+4, n-4, 1);
113 return n;
114 }
115
116 void packet_write(int fd, const char *fmt, ...)
117 {
118 va_list args;
119 unsigned n;
120
121 va_start(args, fmt);
122 n = format_packet(fmt, args);
123 va_end(args);
124 safe_write(fd, buffer, n);
125 }
126
127 void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
128 {
129 va_list args;
130 unsigned n;
131
132 va_start(args, fmt);
133 n = format_packet(fmt, args);
134 va_end(args);
135 strbuf_add(buf, buffer, n);
136 }
137
138 static void safe_read(int fd, void *buffer, unsigned size)
139 {
140 ssize_t ret = read_in_full(fd, buffer, size);
141 if (ret < 0)
142 die_errno("read error");
143 else if (ret < size)
144 die("The remote end hung up unexpectedly");
145 }
146
147 static int packet_length(const char *linelen)
148 {
149 int n;
150 int len = 0;
151
152 for (n = 0; n < 4; n++) {
153 unsigned char c = linelen[n];
154 len <<= 4;
155 if (c >= '0' && c <= '9') {
156 len += c - '0';
157 continue;
158 }
159 if (c >= 'a' && c <= 'f') {
160 len += c - 'a' + 10;
161 continue;
162 }
163 if (c >= 'A' && c <= 'F') {
164 len += c - 'A' + 10;
165 continue;
166 }
167 return -1;
168 }
169 return len;
170 }
171
172 int packet_read_line(int fd, char *buffer, unsigned size)
173 {
174 int len;
175 char linelen[4];
176
177 safe_read(fd, linelen, 4);
178 len = packet_length(linelen);
179 if (len < 0)
180 die("protocol error: bad line length character: %.4s", linelen);
181 if (!len) {
182 packet_trace("0000", 4, 0);
183 return 0;
184 }
185 len -= 4;
186 if (len >= size)
187 die("protocol error: bad line length %d", len);
188 safe_read(fd, buffer, len);
189 buffer[len] = 0;
190 packet_trace(buffer, len, 0);
191 return len;
192 }
193
194 int packet_get_line(struct strbuf *out,
195 char **src_buf, size_t *src_len)
196 {
197 int len;
198
199 if (*src_len < 4)
200 return -1;
201 len = packet_length(*src_buf);
202 if (len < 0)
203 return -1;
204 if (!len) {
205 *src_buf += 4;
206 *src_len -= 4;
207 packet_trace("0000", 4, 0);
208 return 0;
209 }
210 if (*src_len < len)
211 return -2;
212
213 *src_buf += 4;
214 *src_len -= 4;
215 len -= 4;
216
217 strbuf_add(out, *src_buf, len);
218 *src_buf += len;
219 *src_len -= len;
220 packet_trace(out->buf, out->len, 0);
221 return len;
222 }