Mercurial > hg > toybox
annotate toys/pending/tftpd.c @ 1126:2131db66a732 draft
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
| author | Rob Landley <rob@landley.net> |
|---|---|
| date | Wed, 20 Nov 2013 23:01:49 -0600 |
| parents | f7bec236efd3 |
| children | 6df194c6de88 |
| rev | line source |
|---|---|
| 1111 | 1 /* tftpd.c - TFTP server. |
| 2 * | |
| 3 * Copyright 2013 Ranjan Kumar <ranjankumar.bth@gmail.com> | |
| 4 * Copyright 2013 Kyungwan Han <asura321@gmail.com> | |
| 5 * | |
| 6 * No Standard. | |
| 7 | |
|
1126
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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diff
changeset
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8 USE_TFTPD(NEWTOY(tftpd, "rcu:l", TOYFLAG_BIN)) |
| 1111 | 9 |
| 10 config TFTPD | |
| 11 bool "tftpd" | |
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Stuff in pending should default n until cleaned up.
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12 default n |
| 1111 | 13 help |
| 14 usage: tftpd [-cr] [-u USER] [DIR] | |
| 15 | |
| 16 Transfer file from/to tftp server. | |
| 17 | |
| 18 -r Prohibit upload | |
| 19 -c Allow file creation via upload | |
| 20 -u Access files as USER | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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21 -l Log to syslog (inetd mode requires this) |
| 1111 | 22 */ |
| 23 #define FOR_tftpd | |
| 24 #include "toys.h" | |
| 25 | |
| 26 GLOBALS( | |
| 27 char *user; | |
| 28 long sfd; | |
| 29 struct passwd *pw; | |
| 30 ) | |
| 31 | |
| 32 #define TFTPD_BLKSIZE 512 // as per RFC 1350. | |
| 33 | |
| 34 // opcodes | |
| 35 #define TFTPD_OP_RRQ 1 // Read Request RFC 1350, RFC 2090 | |
| 36 #define TFTPD_OP_WRQ 2 // Write Request RFC 1350 | |
| 37 #define TFTPD_OP_DATA 3 // Data chunk RFC 1350 | |
| 38 #define TFTPD_OP_ACK 4 // Acknowledgement RFC 1350 | |
| 39 #define TFTPD_OP_ERR 5 // Error Message RFC 1350 | |
| 40 #define TFTPD_OP_OACK 6 // Option acknowledgment RFC 2347 | |
| 41 | |
| 42 // Error Codes: | |
| 43 #define TFTPD_ER_NOSUCHFILE 1 // File not found | |
| 44 #define TFTPD_ER_ACCESS 2 // Access violation | |
| 45 #define TFTPD_ER_FULL 3 // Disk full or allocation exceeded | |
| 46 #define TFTPD_ER_ILLEGALOP 4 // Illegal TFTP operation | |
| 47 #define TFTPD_ER_UNKID 5 // Unknown transfer ID | |
| 48 #define TFTPD_ER_EXISTS 6 // File already exists | |
| 49 #define TFTPD_ER_UNKUSER 7 // No such user | |
| 50 #define TFTPD_ER_NEGOTIATE 8 // Terminate transfer due to option negotiation | |
| 51 | |
| 52 /* TFTP Packet Formats | |
| 53 * Type Op # Format without header | |
| 54 * 2 bytes string 1 byte string 1 byte | |
| 55 * ----------------------------------------------- | |
| 56 * RRQ/ | 01/02 | Filename | 0 | Mode | 0 | | |
| 57 * WRQ ----------------------------------------------- | |
| 58 * 2 bytes 2 bytes n bytes | |
| 59 * --------------------------------- | |
| 60 * DATA | 03 | Block # | Data | | |
| 61 * --------------------------------- | |
| 62 * 2 bytes 2 bytes | |
| 63 * ------------------- | |
| 64 * ACK | 04 | Block # | | |
| 65 * -------------------- | |
| 66 * 2 bytes 2 bytes string 1 byte | |
| 67 * ---------------------------------------- | |
| 68 * ERROR | 05 | ErrorCode | ErrMsg | 0 | | |
| 69 * ---------------------------------------- | |
| 70 */ | |
| 71 | |
|
1126
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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diff
changeset
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72 static char *g_errpkt = toybuf + TFTPD_BLKSIZE; |
| 1111 | 73 |
| 74 // Create and send error packet. | |
| 75 static void send_errpkt(struct sockaddr *dstaddr, | |
| 76 socklen_t socklen, char *errmsg) | |
| 77 { | |
| 78 error_msg(errmsg); | |
| 79 g_errpkt[1] = TFTPD_OP_ERR; | |
| 80 strcpy(g_errpkt + 4, errmsg); | |
| 81 if (sendto(TT.sfd, g_errpkt, strlen(errmsg)+5, 0, dstaddr, socklen) < 0) | |
| 82 perror_exit("sendto failed"); | |
| 83 } | |
| 84 | |
| 85 // Used to send / receive packets. | |
| 86 static void do_action(struct sockaddr *srcaddr, struct sockaddr *dstaddr, | |
| 87 socklen_t socklen, char *file, int opcode, int tsize, int blksize) | |
| 88 { | |
| 89 int fd, done = 0, retry_count = 12, timeout = 100, len; | |
| 90 uint16_t blockno = 1, pktopcode, rblockno; | |
| 91 char *ptr, *spkt, *rpkt; | |
| 92 struct pollfd pollfds[1]; | |
| 93 | |
| 94 spkt = xzalloc(blksize + 4); | |
| 95 rpkt = xzalloc(blksize + 4); | |
| 96 ptr = spkt+2; //point after opcode. | |
| 97 | |
| 98 pollfds[0].fd = TT.sfd; | |
| 99 // initialize groups, setgid and setuid | |
| 100 if (TT.pw) { | |
| 101 if (change_identity(TT.pw)) perror_exit("Failed to change identity"); | |
| 102 endgrent(); | |
| 103 } | |
| 104 | |
| 105 if (opcode == TFTPD_OP_RRQ) fd = open(file, O_RDONLY, 0666); | |
| 106 else fd = open(file, ((toys.optflags & FLAG_c) ? | |
| 107 (O_WRONLY|O_TRUNC|O_CREAT) : (O_WRONLY|O_TRUNC)) , 0666); | |
| 108 if (fd < 0) { | |
| 109 g_errpkt[3] = TFTPD_ER_NOSUCHFILE; | |
| 110 send_errpkt(dstaddr, socklen, "can't open file"); | |
| 111 goto CLEAN_APP; | |
| 112 } | |
| 113 // For download -> blockno will be 1. | |
| 114 // 1st ACK will be from dst,which will have blockno-=1 | |
| 115 // Create and send ACK packet. | |
| 116 if (blksize != TFTPD_BLKSIZE || tsize) { | |
| 117 pktopcode = TFTPD_OP_OACK; | |
| 118 // add "blksize\000blksize_val\000" in send buffer. | |
| 119 if (blksize != TFTPD_BLKSIZE) { | |
| 120 strcpy(ptr, "blksize"); | |
| 121 ptr += strlen("blksize") + 1; | |
| 122 ptr += snprintf(ptr, 6, "%d", blksize) + 1; | |
| 123 } | |
| 124 if (tsize) {// add "tsize\000tsize_val\000" in send buffer. | |
| 125 struct stat sb; | |
| 126 | |
| 127 sb.st_size = 0; | |
| 128 fstat(fd, &sb); | |
| 129 strcpy(ptr, "tsize"); | |
| 130 ptr += strlen("tsize") + 1; | |
| 131 ptr += sprintf(ptr, "%lu", (unsigned long)sb.st_size)+1; | |
| 132 } | |
| 133 goto SEND_PKT; | |
| 134 } | |
| 135 // upload -> ACK 1st packet with filename, as it has blockno 0. | |
| 136 if (opcode == TFTPD_OP_WRQ) blockno = 0; | |
| 137 | |
| 138 // Prepare DATA and/or ACK pkt and send it. | |
| 139 for (;;) { | |
| 140 int poll_ret; | |
| 141 | |
| 142 retry_count = 12, timeout = 100, pktopcode = TFTPD_OP_ACK; | |
| 143 ptr = spkt+2; | |
| 144 *((uint16_t*)ptr) = htons(blockno); | |
| 145 blockno++; | |
| 146 ptr += 2; | |
| 147 if (opcode == TFTPD_OP_RRQ) { | |
| 148 pktopcode = TFTPD_OP_DATA; | |
| 149 len = readall(fd, ptr, blksize); | |
| 150 if (len < 0) { | |
| 151 send_errpkt(dstaddr, socklen, "read-error"); | |
| 152 break; | |
| 153 } | |
| 154 if (len != blksize) done = 1; //last pkt. | |
| 155 ptr += len; | |
| 156 } | |
| 157 SEND_PKT: | |
| 158 // 1st ACK will be from dst, which will have blockno-=1 | |
| 159 *((uint16_t*)spkt) = htons(pktopcode); //append send pkt's opcode. | |
| 160 RETRY_SEND: | |
| 161 if (sendto(TT.sfd, spkt, (ptr - spkt), 0, dstaddr, socklen) <0) | |
| 162 perror_exit("sendto failed"); | |
| 163 // if "block size < 512", send ACK and exit. | |
| 164 if ((pktopcode == TFTPD_OP_ACK) && done) break; | |
| 165 | |
| 166 POLL_IN: | |
| 167 pollfds[0].events = POLLIN; | |
| 168 pollfds[0].fd = TT.sfd; | |
| 169 poll_ret = poll(pollfds, 1, timeout); | |
| 170 if (poll_ret < 0 && (errno == EINTR || errno == ENOMEM)) goto POLL_IN; | |
| 171 if (!poll_ret) { | |
| 172 if (!--retry_count) { | |
| 173 error_msg("timeout"); | |
| 174 break; | |
| 175 } | |
| 176 timeout += 150; | |
| 177 goto RETRY_SEND; | |
| 178 } else if (poll_ret == 1) { | |
| 179 len = read(pollfds[0].fd, rpkt, blksize + 4); | |
| 180 if (len < 0) { | |
| 181 send_errpkt(dstaddr, socklen, "read-error"); | |
| 182 break; | |
| 183 } | |
| 184 if (len < 4) goto POLL_IN; | |
| 185 } else { | |
| 186 perror_msg("poll"); | |
| 187 break; | |
| 188 } | |
| 189 // Validate receive packet. | |
| 190 pktopcode = ntohs(((uint16_t*)rpkt)[0]); | |
| 191 rblockno = ntohs(((uint16_t*)rpkt)[1]); | |
| 192 if (pktopcode == TFTPD_OP_ERR) { | |
|
1126
2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
1112
diff
changeset
|
193 char *message = "DATA Check failure."; |
|
2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
1112
diff
changeset
|
194 char *arr[] = {"File not found", "Access violation", |
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2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
1112
diff
changeset
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195 "Disk full or allocation exceeded", "Illegal TFTP operation", |
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2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
1112
diff
changeset
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196 "Unknown transfer ID", "File already exists", |
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2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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diff
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197 "No such user", "Terminate transfer due to option negotiation"}; |
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2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
1112
diff
changeset
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198 |
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2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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diff
changeset
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199 if (rblockno && (rblockno < 9)) message = arr[rblockno - 1]; |
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2131db66a732
tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
1112
diff
changeset
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200 error_msg(message); |
| 1111 | 201 break; // Break the for loop. |
| 202 } | |
| 203 | |
| 204 // if download requested by client, | |
| 205 // server will send data pkt and will receive ACK pkt from client. | |
| 206 if ((opcode == TFTPD_OP_RRQ) && (pktopcode == TFTPD_OP_ACK)) { | |
| 207 if (rblockno == (uint16_t) (blockno - 1)) { | |
| 208 if (!done) continue; // Send next chunk of data. | |
| 209 break; | |
| 210 } | |
| 211 } | |
| 212 | |
| 213 // server will receive DATA pkt and write the data. | |
| 214 if ((opcode == TFTPD_OP_WRQ) && (pktopcode == TFTPD_OP_DATA)) { | |
| 215 if (rblockno == blockno) { | |
| 216 int nw = writeall(fd, &rpkt[4], len-4); | |
| 217 if (nw != len-4) { | |
| 218 g_errpkt[3] = TFTPD_ER_FULL; | |
| 219 send_errpkt(dstaddr, socklen, "write error"); | |
| 220 break; | |
| 221 } | |
| 222 | |
| 223 if (nw != blksize) done = 1; | |
| 224 } | |
| 225 continue; | |
| 226 } | |
| 227 goto POLL_IN; | |
| 228 } // end of loop | |
| 229 | |
| 230 CLEAN_APP: | |
| 231 if (CFG_TOYBOX_FREE) { | |
| 232 free(spkt); | |
| 233 free(rpkt); | |
| 234 close(fd); | |
| 235 } | |
| 236 } | |
| 237 | |
| 238 void tftpd_main(void) | |
| 239 { | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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240 int recvmsg_len, rbuflen, opcode, blksize = TFTPD_BLKSIZE, tsize = 0, set =1; |
| 1111 | 241 struct sockaddr_storage srcaddr, dstaddr; |
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parents:
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242 socklen_t socklen = sizeof(struct sockaddr_storage); |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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diff
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243 char *buf = toybuf; |
| 1111 | 244 |
| 245 TT.pw = NULL; | |
| 246 memset(&srcaddr, 0, sizeof(srcaddr)); | |
| 247 if (getsockname(STDIN_FILENO, (struct sockaddr*)&srcaddr, &socklen)) { | |
| 248 toys.exithelp = 1; | |
| 249 error_exit(NULL); | |
| 250 } | |
| 251 | |
| 252 if (toys.optflags & FLAG_u) { | |
| 253 struct passwd *pw = getpwnam(TT.user); | |
| 254 if (!pw) error_exit("unknown user %s", TT.user); | |
| 255 TT.pw = pw; | |
| 256 } | |
| 257 if (*toys.optargs) { | |
| 258 if (chroot(*toys.optargs)) | |
| 259 perror_exit("can't change root directory to '%s'", *toys.optargs); | |
| 260 if (chdir("/")) perror_exit("can't change directory to '/'"); | |
| 261 } | |
| 262 | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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263 recvmsg_len = recvfrom(STDIN_FILENO, toybuf, TFTPD_BLKSIZE, 0, |
| 1111 | 264 (struct sockaddr*)&dstaddr, &socklen); |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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265 |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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266 TT.sfd = xsocket(((struct sockaddr*)&dstaddr)->sa_family, SOCK_DGRAM, 0); |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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267 if (setsockopt(TT.sfd, SOL_SOCKET, SO_REUSEADDR, (const void *)&set, |
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parents:
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268 sizeof(set)) < 0) perror_exit("setsockopt failed"); |
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269 if (bind(TT.sfd, (struct sockaddr*)&srcaddr, socklen)) perror_exit("bind"); |
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parents:
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270 if (connect(TT.sfd, (struct sockaddr*)&dstaddr, socklen) < 0) |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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diff
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271 perror_exit("can't connect to remote host"); |
| 1111 | 272 // Error condition. |
| 273 if (recvmsg_len < 4 || recvmsg_len > TFTPD_BLKSIZE | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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diff
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274 || toybuf[recvmsg_len-1] != '\0') { |
| 1111 | 275 send_errpkt((struct sockaddr*)&dstaddr, socklen, "packet format error"); |
| 276 return; | |
| 277 } | |
| 278 | |
| 279 // request is either upload or Download. | |
| 280 opcode = ntohs(*(uint16_t*)buf); | |
| 281 if (((opcode != TFTPD_OP_RRQ) && (opcode != TFTPD_OP_WRQ)) | |
| 282 || ((opcode == TFTPD_OP_WRQ) && (toys.optflags & FLAG_r))) { | |
| 283 send_errpkt((struct sockaddr*)&dstaddr, socklen, | |
| 284 ((opcode == TFTPD_OP_WRQ) ? "write error" : "packet format error")); | |
| 285 return; | |
| 286 } | |
| 287 | |
| 288 buf += 2; | |
| 289 if (*buf == '.' || strstr(buf, "/.")) { | |
| 290 send_errpkt((struct sockaddr*)&dstaddr, socklen, "dot in filename"); | |
| 291 return; | |
| 292 } | |
| 293 | |
| 294 buf += strlen(buf) + 1; //1 '\0'. | |
| 295 // As per RFC 1350, mode is case in-sensitive. | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
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parents:
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296 if ((buf >= (toybuf + recvmsg_len)) || (strcasecmp(buf, "octet"))) { |
| 1111 | 297 send_errpkt((struct sockaddr*)&dstaddr, socklen, "packet format error"); |
| 298 return; | |
| 299 } | |
| 300 | |
| 301 //RFC2348. e.g. of size type: "ttype1\0ttype1_val\0...ttypeN\0ttypeN_val\0" | |
| 302 buf += strlen(buf) + 1; | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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303 rbuflen = toybuf + recvmsg_len - buf; |
| 1111 | 304 if (rbuflen) { |
| 305 int jump = 0, bflag = 0; | |
| 306 | |
| 307 for (; rbuflen; rbuflen -= jump, buf += jump) { | |
| 308 if (!bflag && !strcasecmp(buf, "blksize")) { //get blksize | |
| 309 errno = 0; | |
| 310 blksize = strtoul(buf, NULL, 10); | |
| 311 if (errno || blksize > 65564 || blksize < 8) blksize = TFTPD_BLKSIZE; | |
| 312 bflag ^= 1; | |
| 313 } else if (!tsize && !strcasecmp(buf, "tsize")) tsize ^= 1; | |
| 314 | |
| 315 jump += strlen(buf) + 1; | |
| 316 } | |
| 317 tsize &= (opcode == TFTPD_OP_RRQ); | |
| 318 } | |
| 319 | |
| 320 //do send / receive file. | |
| 321 do_action((struct sockaddr*)&srcaddr, (struct sockaddr*)&dstaddr, | |
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tftpd upgrade from Ashwini Sharma based on comments from Felix Janda.
Rob Landley <rob@landley.net>
parents:
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diff
changeset
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322 socklen, toybuf + 2, opcode, tsize, blksize); |
| 1111 | 323 if (CFG_TOYBOX_FREE) close(STDIN_FILENO); |
| 324 } |