tftp: on download, open local file only when first bit of data arrived
No reason to potentially clobber existing file before absolutely necessary. function old new delta tftp_protocol 1947 2020 +73 tftp_main 393 376 -17 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/1 up/down: 73/-17) Total: 56 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
parent
0c4e5977df
commit
adc540f0db
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@ -319,7 +319,7 @@ static int tftp_protocol(
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uint16_t opcode;
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uint16_t block_nr;
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uint16_t recv_blk;
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int open_mode, local_fd;
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int local_fd = -1;
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int retries, waittime_ms;
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int io_bufsize = blksize + 4;
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char *cp;
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@ -354,19 +354,6 @@ static int tftp_protocol(
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}
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}
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/* Prepare open mode */
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if (CMD_PUT(option_mask32)) {
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open_mode = O_RDONLY;
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} else {
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open_mode = O_WRONLY | O_TRUNC | O_CREAT;
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#if ENABLE_TFTPD
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if ((option_mask32 & (TFTPD_OPT+TFTPD_OPT_c)) == TFTPD_OPT) {
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/* tftpd without -c */
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open_mode = O_WRONLY | O_TRUNC;
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}
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#endif
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}
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/* Examples of network traffic.
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* Note two cases when ACKs with block# of 0 are sent.
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*
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@ -400,6 +387,14 @@ static int tftp_protocol(
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if (!ENABLE_TFTP || our_lsa) { /* tftpd */
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/* Open file (must be after changing user) */
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int open_mode = O_RDONLY;
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if (CMD_GET(option_mask32)) {
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open_mode = O_WRONLY | O_TRUNC | O_CREAT;
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if ((option_mask32 & (TFTPD_OPT+TFTPD_OPT_c)) == TFTPD_OPT) {
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/* tftpd without -c */
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open_mode = O_WRONLY | O_TRUNC;
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}
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}
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local_fd = open(local_file, open_mode, 0666);
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if (local_fd < 0) {
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/* sanitize name, it came from untrusted remote side */
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@ -414,6 +409,7 @@ static int tftp_protocol(
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strcpy(G_error_pkt_str, "can't open file");
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goto send_err_pkt_nomsg;
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}
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/* gcc 4.3.1 would NOT optimize it out as it should! */
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#if ENABLE_FEATURE_TFTP_BLOCKSIZE
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if (blksize != TFTP_BLKSIZE_DEFAULT || want_transfer_size) {
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@ -432,10 +428,11 @@ static int tftp_protocol(
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block_nr = 0;
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}
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} else { /* tftp */
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/* Open file (must be after changing user) */
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local_fd = CMD_GET(option_mask32) ? STDOUT_FILENO : STDIN_FILENO;
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if (NOT_LONE_DASH(local_file))
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local_fd = xopen(local_file, open_mode);
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if (CMD_PUT(option_mask32)) {
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local_fd = STDIN_FILENO;
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if (local_file)
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local_fd = xopen(local_file, O_RDONLY);
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}
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/* Removing #if, or using if() statement instead of #if may lead to
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* "warning: null argument where non-null required": */
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#if ENABLE_TFTP
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@ -491,7 +488,7 @@ static int tftp_protocol(
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}
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if (want_transfer_size) {
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/* add "tsize", <nul>, size, <nul> (see RFC2349) */
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/* if tftp and downloading, we send "0" (since we opened local_fd with O_TRUNC)
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/* if tftp and downloading, we send "0" (local_fd is not open yet)
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* and this makes server to send "tsize" option with the size */
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/* if tftp and uploading, we send file size (maybe dont, to not confuse old servers???) */
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/* if tftpd and downloading, we are answering to client's request */
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@ -500,7 +497,8 @@ static int tftp_protocol(
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strcpy(cp, "tsize");
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cp += sizeof("tsize");
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st.st_size = 0;
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fstat(local_fd, &st);
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if (local_fd >= 0)
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fstat(local_fd, &st);
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cp += sprintf(cp, "%"OFF_FMT"u", (off_t)st.st_size) + 1;
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# if ENABLE_FEATURE_TFTP_PROGRESS_BAR
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/* Save for progress bar. If 0 (tftp downloading),
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@ -690,7 +688,13 @@ static int tftp_protocol(
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if (CMD_GET(option_mask32) && (opcode == TFTP_DATA)) {
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if (recv_blk == block_nr) {
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int sz = full_write(local_fd, &rbuf[4], len - 4);
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int sz;
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if (local_fd == -1) {
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local_fd = STDOUT_FILENO;
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if (local_file)
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local_fd = xopen(local_file, O_WRONLY | O_TRUNC | O_CREAT);
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}
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sz = full_write(local_fd, &rbuf[4], len - 4);
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if (sz != len - 4) {
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strcpy(G_error_pkt_str, bb_msg_write_error);
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G_error_pkt_reason = ERR_WRITE;
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@ -739,7 +743,9 @@ static int tftp_protocol(
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free(xbuf);
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free(rbuf);
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}
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return finished == 0; /* returns 1 on failure */
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if (!finished)
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goto err;
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return EXIT_SUCCESS;
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send_read_err_pkt:
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strcpy(G_error_pkt_str, bb_msg_read_error);
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@ -750,6 +756,9 @@ static int tftp_protocol(
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G.error_pkt[1] = TFTP_ERROR;
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xsendto(socket_fd, G.error_pkt, 4 + 1 + strlen(G_error_pkt_str),
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&peer_lsa->u.sa, peer_lsa->len);
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err:
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if (local_fd >= 0 && CMD_GET(option_mask32) && local_file)
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unlink(local_file);
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return EXIT_FAILURE;
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#undef remote_file
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}
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@ -767,7 +776,6 @@ int tftp_main(int argc UNUSED_PARAM, char **argv)
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# endif
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int result;
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int port;
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IF_GETPUT(int opt;)
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INIT_G();
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@ -808,7 +816,7 @@ int tftp_main(int argc UNUSED_PARAM, char **argv)
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}
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}
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IF_GETPUT(opt =) getopt32(argv, "^"
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getopt32(argv, "^"
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IF_FEATURE_TFTP_GET("g") IF_FEATURE_TFTP_PUT("p")
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"l:r:" IF_FEATURE_TFTP_BLOCKSIZE("b:")
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IF_FEATURE_TFTP_HPA_COMPAT("m:")
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@ -859,15 +867,12 @@ int tftp_main(int argc UNUSED_PARAM, char **argv)
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# endif
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result = tftp_protocol(
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NULL /*our_lsa*/, peer_lsa,
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local_file, remote_file
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(LONE_DASH(local_file) ? NULL : local_file), remote_file
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IF_FEATURE_TFTP_BLOCKSIZE(, 1 /* want_transfer_size */)
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IF_FEATURE_TFTP_BLOCKSIZE(, blksize)
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);
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tftp_progress_done();
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if (result != EXIT_SUCCESS && NOT_LONE_DASH(local_file) && CMD_GET(opt)) {
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unlink(local_file);
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}
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return result;
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}
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#endif /* ENABLE_TFTP */
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