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 int packet_flush_gently(int fd); 33 int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); 34 int write_packetized_from_fd_no_flush(int fd_in, int fd_out); 35 int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out); 36 37 /* 38 * Stdio versions of packet_write functions. When mixing these with fd 39 * based functions, take care to call fflush(3) before doing fd writes or 40 * closing the fd. 41 */ 42 void packet_fwrite(FILE *f, const char *buf, size_t size); 43 void packet_fwrite_fmt(FILE *f, const char *fmt, ...) __attribute__((format (printf, 2, 3))); 44 45 /* packet_fflush writes a flush packet and flushes the stdio buffer of f */ 46 void packet_fflush(FILE *f); 47 48 /* 49 * Read a packetized line into the buffer, which must be at least size bytes 50 * long. The return value specifies the number of bytes read into the buffer. 51 * 52 * If src_buffer and *src_buffer are not NULL, it should point to a buffer 53 * containing the packet data to parse, of at least *src_len bytes. After the 54 * function returns, src_buf will be incremented and src_len decremented by the 55 * number of bytes consumed. 56 * 57 * If src_buffer (or *src_buffer) is NULL, then data is read from the 58 * descriptor "fd". 59 * 60 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any 61 * of the following conditions: 62 * 63 * 1. Read error from descriptor. 64 * 65 * 2. Protocol error from the remote (e.g., bogus length characters). 66 * 67 * 3. Receiving a packet larger than "size" bytes. 68 * 69 * 4. Truncated output from the remote (e.g., we expected a packet but got 70 * EOF, or we got a partial packet followed by EOF). 71 * 72 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on 73 * condition 4 (truncated input), but instead return -1. However, we will still 74 * die for the other 3 conditions. 75 * 76 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if 77 * present) is removed from the buffer before returning. 78 * 79 * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an 80 * ERR packet. 81 * 82 * If options contains PACKET_READ_GENTLE_ON_READ_ERROR, we will not die 83 * on read errors, but instead return -1. However, we may still die on an 84 * ERR packet (if requested). 85 */ 86 #define PACKET_READ_GENTLE_ON_EOF (1u<<0) 87 #define PACKET_READ_CHOMP_NEWLINE (1u<<1) 88 #define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2) 89 #define PACKET_READ_GENTLE_ON_READ_ERROR (1u<<3) 90 int packet_read(int fd, char *buffer, unsigned size, int options); 91 92 /* 93 * Convert a four hex digit packet line length header into its numeric 94 * representation. 95 * 96 * If lenbuf_hex contains non-hex characters, return -1. Otherwise, return the 97 * numeric value of the length header. 98 */ 99 int packet_length(const char lenbuf_hex[4]); 100 101 /* 102 * Read a packetized line into a buffer like the 'packet_read()' function but 103 * returns an 'enum packet_read_status' which indicates the status of the read. 104 * The number of bytes read will be assigned to *pktlen if the status of the 105 * read was 'PACKET_READ_NORMAL'. 106 */ 107 enum packet_read_status { 108 PACKET_READ_EOF, 109 PACKET_READ_NORMAL, 110 PACKET_READ_FLUSH, 111 PACKET_READ_DELIM, 112 PACKET_READ_RESPONSE_END, 113 }; 114 enum packet_read_status packet_read_with_status(int fd, char **src_buffer, 115 size_t *src_len, char *buffer, 116 unsigned size, int *pktlen, 117 int options); 118 119 /* 120 * Convenience wrapper for packet_read that is not gentle, and sets the 121 * CHOMP_NEWLINE option. The return value is NULL for a flush packet, 122 * and otherwise points to a static buffer (that may be overwritten by 123 * subsequent calls). If the size parameter is not NULL, the length of the 124 * packet is written to it. 125 */ 126 char *packet_read_line(int fd, int *size); 127 128 /* 129 * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF 130 * and CHOMP_NEWLINE options. The return value specifies the number of bytes 131 * read into the buffer or -1 on truncated input. If the *dst_line parameter 132 * is not NULL it will return NULL for a flush packet or when the number of 133 * bytes copied is zero and otherwise points to a static buffer (that may be 134 * overwritten by subsequent calls). If the size parameter is not NULL, the 135 * length of the packet is written to it. 136 */ 137 int packet_read_line_gently(int fd, int *size, char **dst_line); 138 139 /* 140 * Reads a stream of variable sized packets until a flush packet is detected. 141 */ 142 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options); 143 144 /* 145 * Receive multiplexed output stream over git native protocol. 146 * in_stream is the input stream from the remote, which carries data 147 * in pkt_line format with band designator. Demultiplex it into out 148 * and err and return error appropriately. Band #1 carries the 149 * primary payload. Things coming over band #2 is not necessarily 150 * error; they are usually informative message on the standard error 151 * stream, aka "verbose"). A message over band #3 is a signal that 152 * the remote died unexpectedly. A flush() concludes the stream. 153 * 154 * Returns SIDEBAND_FLUSH upon a normal conclusion, and SIDEBAND_PROTOCOL_ERROR 155 * or SIDEBAND_REMOTE_ERROR if an error occurred. 156 */ 157 int recv_sideband(const char *me, int in_stream, int out); 158 159 struct packet_reader { 160 /* source file descriptor */ 161 int fd; 162 163 /* source buffer and its size */ 164 char *src_buffer; 165 size_t src_len; 166 167 /* buffer that pkt-lines are read into and its size */ 168 char *buffer; 169 unsigned buffer_size; 170 171 /* options to be used during reads */ 172 int options; 173 174 /* status of the last read */ 175 enum packet_read_status status; 176 177 /* length of data read during the last read */ 178 int pktlen; 179 180 /* the last line read */ 181 const char *line; 182 183 /* indicates if a line has been peeked */ 184 int line_peeked; 185 186 unsigned use_sideband : 1; 187 const char *me; 188 189 /* hash algorithm in use */ 190 const struct git_hash_algo *hash_algo; 191 }; 192 193 /* 194 * Initialize a 'struct packet_reader' object which is an 195 * abstraction around the 'packet_read_with_status()' function. 196 */ 197 void packet_reader_init(struct packet_reader *reader, int fd, 198 char *src_buffer, size_t src_len, 199 int options); 200 201 /* 202 * Perform a packet read and return the status of the read. 203 * The values of 'pktlen' and 'line' are updated based on the status of the 204 * read as follows: 205 * 206 * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL 207 * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read 208 * 'line' is set to point at the read line 209 * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL 210 */ 211 enum packet_read_status packet_reader_read(struct packet_reader *reader); 212 213 /* 214 * Peek the next packet line without consuming it and return the status. 215 * The next call to 'packet_reader_read()' will perform a read of the same line 216 * that was peeked, consuming the line. 217 * 218 * Peeking multiple times without calling 'packet_reader_read()' will return 219 * the same result. 220 */ 221 enum packet_read_status packet_reader_peek(struct packet_reader *reader); 222 223 #define DEFAULT_PACKET_MAX 1000 224 #define LARGE_PACKET_MAX 65520 225 #define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4) 226 extern char packet_buffer[LARGE_PACKET_MAX]; 227 228 struct packet_writer { 229 int dest_fd; 230 unsigned use_sideband : 1; 231 }; 232 233 void packet_writer_init(struct packet_writer *writer, int dest_fd); 234 235 /* These functions die upon failure. */ 236 __attribute__((format (printf, 2, 3))) 237 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...); 238 __attribute__((format (printf, 2, 3))) 239 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...); 240 void packet_writer_delim(struct packet_writer *writer); 241 void packet_writer_flush(struct packet_writer *writer); 242 243 #endif 244