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1 | #ifndef PKTLINE_H | |
2 | #define PKTLINE_H | |
3 | ||
4 | #include "git-compat-util.h" | |
5 | #include "strbuf.h" | |
6 | #include "sideband.h" | |
7 | ||
8 | /* | |
9 | * Write a packetized stream, where each line is preceded by | |
10 | * its length (including the header) as a 4-byte hex number. | |
11 | * A length of 'zero' means end of stream (and a length of 1-3 | |
12 | * would be an error). | |
13 | * | |
14 | * This is all pretty stupid, but we use this packetized line | |
15 | * format to make a streaming format possible without ever | |
16 | * over-running the read buffers. That way we'll never read | |
17 | * into what might be the pack data (which should go to another | |
18 | * process entirely). | |
19 | * | |
20 | * The writing side could use stdio, but since the reading | |
21 | * side can't, we stay with pure read/write interfaces. | |
22 | */ | |
23 | void packet_flush(int fd); | |
24 | void packet_delim(int fd); | |
25 | void packet_response_end(int fd); | |
26 | void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); | |
27 | void packet_buf_flush(struct strbuf *buf); | |
28 | void packet_buf_delim(struct strbuf *buf); | |
29 | void set_packet_header(char *buf, int size); | |
30 | void packet_write(int fd_out, const char *buf, size_t size); | |
31 | void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3))); | |
32 | void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len); | |
33 | int packet_flush_gently(int fd); | |
34 | int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); | |
35 | int write_packetized_from_fd(int fd_in, int fd_out); | |
36 | int write_packetized_from_buf(const char *src_in, size_t len, int fd_out); | |
37 | ||
38 | /* | |
39 | * Read a packetized line into the buffer, which must be at least size bytes | |
40 | * long. The return value specifies the number of bytes read into the buffer. | |
41 | * | |
42 | * If src_buffer and *src_buffer are not NULL, it should point to a buffer | |
43 | * containing the packet data to parse, of at least *src_len bytes. After the | |
44 | * function returns, src_buf will be incremented and src_len decremented by the | |
45 | * number of bytes consumed. | |
46 | * | |
47 | * If src_buffer (or *src_buffer) is NULL, then data is read from the | |
48 | * descriptor "fd". | |
49 | * | |
50 | * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any | |
51 | * of the following conditions: | |
52 | * | |
53 | * 1. Read error from descriptor. | |
54 | * | |
55 | * 2. Protocol error from the remote (e.g., bogus length characters). | |
56 | * | |
57 | * 3. Receiving a packet larger than "size" bytes. | |
58 | * | |
59 | * 4. Truncated output from the remote (e.g., we expected a packet but got | |
60 | * EOF, or we got a partial packet followed by EOF). | |
61 | * | |
62 | * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on | |
63 | * condition 4 (truncated input), but instead return -1. However, we will still | |
64 | * die for the other 3 conditions. | |
65 | * | |
66 | * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if | |
67 | * present) is removed from the buffer before returning. | |
68 | * | |
69 | * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an | |
70 | * ERR packet. | |
71 | */ | |
72 | #define PACKET_READ_GENTLE_ON_EOF (1u<<0) | |
73 | #define PACKET_READ_CHOMP_NEWLINE (1u<<1) | |
74 | #define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2) | |
75 | int packet_read(int fd, char **src_buffer, size_t *src_len, char | |
76 | *buffer, unsigned size, int options); | |
77 | ||
78 | /* | |
79 | * Convert a four hex digit packet line length header into its numeric | |
80 | * representation. | |
81 | * | |
82 | * If lenbuf_hex contains non-hex characters, return -1. Otherwise, return the | |
83 | * numeric value of the length header. | |
84 | */ | |
85 | int packet_length(const char lenbuf_hex[4]); | |
86 | ||
87 | /* | |
88 | * Read a packetized line into a buffer like the 'packet_read()' function but | |
89 | * returns an 'enum packet_read_status' which indicates the status of the read. | |
90 | * The number of bytes read will be assigned to *pktlen if the status of the | |
91 | * read was 'PACKET_READ_NORMAL'. | |
92 | */ | |
93 | enum packet_read_status { | |
94 | PACKET_READ_EOF, | |
95 | PACKET_READ_NORMAL, | |
96 | PACKET_READ_FLUSH, | |
97 | PACKET_READ_DELIM, | |
98 | PACKET_READ_RESPONSE_END, | |
99 | }; | |
100 | enum packet_read_status packet_read_with_status(int fd, char **src_buffer, | |
101 | size_t *src_len, char *buffer, | |
102 | unsigned size, int *pktlen, | |
103 | int options); | |
104 | ||
105 | /* | |
106 | * Convenience wrapper for packet_read that is not gentle, and sets the | |
107 | * CHOMP_NEWLINE option. The return value is NULL for a flush packet, | |
108 | * and otherwise points to a static buffer (that may be overwritten by | |
109 | * subsequent calls). If the size parameter is not NULL, the length of the | |
110 | * packet is written to it. | |
111 | */ | |
112 | char *packet_read_line(int fd, int *size); | |
113 | ||
114 | /* | |
115 | * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF | |
116 | * and CHOMP_NEWLINE options. The return value specifies the number of bytes | |
117 | * read into the buffer or -1 on truncated input. If the *dst_line parameter | |
118 | * is not NULL it will return NULL for a flush packet or when the number of | |
119 | * bytes copied is zero and otherwise points to a static buffer (that may be | |
120 | * overwritten by subsequent calls). If the size parameter is not NULL, the | |
121 | * length of the packet is written to it. | |
122 | */ | |
123 | int packet_read_line_gently(int fd, int *size, char **dst_line); | |
124 | ||
125 | /* | |
126 | * Same as packet_read_line, but read from a buf rather than a descriptor; | |
127 | * see packet_read for details on how src_* is used. | |
128 | */ | |
129 | char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size); | |
130 | ||
131 | /* | |
132 | * Reads a stream of variable sized packets until a flush packet is detected. | |
133 | */ | |
134 | ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out); | |
135 | ||
136 | /* | |
137 | * Receive multiplexed output stream over git native protocol. | |
138 | * in_stream is the input stream from the remote, which carries data | |
139 | * in pkt_line format with band designator. Demultiplex it into out | |
140 | * and err and return error appropriately. Band #1 carries the | |
141 | * primary payload. Things coming over band #2 is not necessarily | |
142 | * error; they are usually informative message on the standard error | |
143 | * stream, aka "verbose"). A message over band #3 is a signal that | |
144 | * the remote died unexpectedly. A flush() concludes the stream. | |
145 | * | |
146 | * Returns SIDEBAND_FLUSH upon a normal conclusion, and SIDEBAND_PROTOCOL_ERROR | |
147 | * or SIDEBAND_REMOTE_ERROR if an error occurred. | |
148 | */ | |
149 | int recv_sideband(const char *me, int in_stream, int out); | |
150 | ||
151 | struct packet_reader { | |
152 | /* source file descriptor */ | |
153 | int fd; | |
154 | ||
155 | /* source buffer and its size */ | |
156 | char *src_buffer; | |
157 | size_t src_len; | |
158 | ||
159 | /* buffer that pkt-lines are read into and its size */ | |
160 | char *buffer; | |
161 | unsigned buffer_size; | |
162 | ||
163 | /* options to be used during reads */ | |
164 | int options; | |
165 | ||
166 | /* status of the last read */ | |
167 | enum packet_read_status status; | |
168 | ||
169 | /* length of data read during the last read */ | |
170 | int pktlen; | |
171 | ||
172 | /* the last line read */ | |
173 | const char *line; | |
174 | ||
175 | /* indicates if a line has been peeked */ | |
176 | int line_peeked; | |
177 | ||
178 | unsigned use_sideband : 1; | |
179 | const char *me; | |
180 | ||
181 | /* hash algorithm in use */ | |
182 | const struct git_hash_algo *hash_algo; | |
183 | }; | |
184 | ||
185 | /* | |
186 | * Initialize a 'struct packet_reader' object which is an | |
187 | * abstraction around the 'packet_read_with_status()' function. | |
188 | */ | |
189 | void packet_reader_init(struct packet_reader *reader, int fd, | |
190 | char *src_buffer, size_t src_len, | |
191 | int options); | |
192 | ||
193 | /* | |
194 | * Perform a packet read and return the status of the read. | |
195 | * The values of 'pktlen' and 'line' are updated based on the status of the | |
196 | * read as follows: | |
197 | * | |
198 | * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL | |
199 | * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read | |
200 | * 'line' is set to point at the read line | |
201 | * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL | |
202 | */ | |
203 | enum packet_read_status packet_reader_read(struct packet_reader *reader); | |
204 | ||
205 | /* | |
206 | * Peek the next packet line without consuming it and return the status. | |
207 | * The next call to 'packet_reader_read()' will perform a read of the same line | |
208 | * that was peeked, consuming the line. | |
209 | * | |
210 | * Peeking multiple times without calling 'packet_reader_read()' will return | |
211 | * the same result. | |
212 | */ | |
213 | enum packet_read_status packet_reader_peek(struct packet_reader *reader); | |
214 | ||
215 | #define DEFAULT_PACKET_MAX 1000 | |
216 | #define LARGE_PACKET_MAX 65520 | |
217 | #define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4) | |
218 | extern char packet_buffer[LARGE_PACKET_MAX]; | |
219 | ||
220 | struct packet_writer { | |
221 | int dest_fd; | |
222 | unsigned use_sideband : 1; | |
223 | }; | |
224 | ||
225 | void packet_writer_init(struct packet_writer *writer, int dest_fd); | |
226 | ||
227 | /* These functions die upon failure. */ | |
228 | __attribute__((format (printf, 2, 3))) | |
229 | void packet_writer_write(struct packet_writer *writer, const char *fmt, ...); | |
230 | __attribute__((format (printf, 2, 3))) | |
231 | void packet_writer_error(struct packet_writer *writer, const char *fmt, ...); | |
232 | void packet_writer_delim(struct packet_writer *writer); | |
233 | void packet_writer_flush(struct packet_writer *writer); | |
234 | ||
235 | #endif |