httpd: simplify CGI i/o loop. -200 bytes.
This commit is contained in:
Denis Vlasenko
parent
9a4e08eaa8
commit
32a471e4db
@ -104,12 +104,15 @@
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//#define DEBUG 1
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#define DEBUG 0
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#define IOBUF_SIZE 8192 /* IO buffer */
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/* amount of buffering in a pipe */
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#ifndef PIPE_BUF
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# define PIPE_BUF 4096
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#endif
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#define IOBUF_SIZE 8192 /* IO buffer */
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#if PIPE_BUF >= IOBUF_SIZE
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# error "PIPE_BUF >= IOBUF_SIZE"
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#endif
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#define HEADER_READ_TIMEOUT 60
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@ -1029,6 +1032,173 @@ static int get_line(void)
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}
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#if ENABLE_FEATURE_HTTPD_CGI
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/* gcc 4.2.1 fares better with NOINLINE */
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static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post_len) ATTRIBUTE_NORETURN;
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static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post_len)
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{
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enum { FROM_CGI = 1, TO_CGI = 2 }; /* indexes in pfd[] */
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struct pollfd pfd[3];
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int out_cnt; /* we buffer a bit of initial CGI output */
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int count;
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/* iobuf is used for CGI -> network data,
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* hdr_buf is for network -> CGI data (POSTDATA) */
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/* If CGI dies, we still want to correctly finish reading its output
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* and send it to the peer. So please no SIGPIPEs! */
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signal(SIGPIPE, SIG_IGN);
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/* NB: breaking out of this loop jumps to log_and_exit() */
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out_cnt = 0;
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while (1) {
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memset(pfd, 0, sizeof(pfd));
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pfd[FROM_CGI].fd = fromCgi_rd;
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pfd[FROM_CGI].events = POLLIN;
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if (toCgi_wr) {
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pfd[TO_CGI].fd = toCgi_wr;
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if (hdr_cnt > 0) {
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pfd[TO_CGI].events = POLLOUT;
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} else if (post_len > 0) {
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pfd[0].events = POLLIN;
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} else {
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/* post_len <= 0 && hdr_cnt <= 0:
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* no more POST data to CGI,
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* let CGI see EOF on CGI's stdin */
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close(toCgi_wr);
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toCgi_wr = 0;
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}
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}
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/* Now wait on the set of sockets */
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count = poll(pfd, 3, -1);
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if (count <= 0) {
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#if 0
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if (errno == EINTR)
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continue;
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#endif
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#if 0
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if (waitpid(pid, &status, WNOHANG) <= 0) {
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/* Weird. CGI didn't exit and no fd's
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* are ready, yet poll returned?! */
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continue;
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}
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if (DEBUG && WIFEXITED(status))
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bb_error_msg("CGI exited, status=%d", WEXITSTATUS(status));
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if (DEBUG && WIFSIGNALED(status))
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bb_error_msg("CGI killed, signal=%d", WTERMSIG(status));
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#endif
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break;
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}
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if (pfd[TO_CGI].revents) {
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/* hdr_cnt > 0 here due to the way pfd[TO_CGI].events set */
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/* Have data from peer and can write to CGI */
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count = safe_write(toCgi_wr, hdr_ptr, hdr_cnt);
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/* Doesn't happen, we dont use nonblocking IO here
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*if (count < 0 && errno == EAGAIN) {
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* ...
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*} else */
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if (count > 0) {
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hdr_ptr += count;
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hdr_cnt -= count;
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} else {
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/* EOF/broken pipe to CGI, stop piping POST data */
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hdr_cnt = post_len = 0;
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}
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}
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if (pfd[0].revents) {
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/* post_len > 0 && hdr_cnt == 0 here */
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/* We expect data, prev data portion is eaten by CGI
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* and there *is* data to read from the peer
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* (POSTDATA) */
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//count = post_len > (int)sizeof(hdr_buf) ? (int)sizeof(hdr_buf) : post_len;
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//count = safe_read(0, hdr_buf, count);
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count = safe_read(0, hdr_buf, sizeof(hdr_buf));
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if (count > 0) {
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hdr_cnt = count;
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hdr_ptr = hdr_buf;
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post_len -= count;
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} else {
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/* no more POST data can be read */
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post_len = 0;
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}
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}
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if (pfd[FROM_CGI].revents) {
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/* There is something to read from CGI */
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char *rbuf = iobuf;
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/* Are we still buffering CGI output? */
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if (out_cnt >= 0) {
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/* HTTP_200[] has single "\r\n" at the end.
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* According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html,
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* CGI scripts MUST send their own header terminated by
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* empty line, then data. That's why we have only one
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* <cr><lf> pair here. We will output "200 OK" line
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* if needed, but CGI still has to provide blank line
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* between header and body */
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/* Must use safe_read, not full_read, because
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* CGI may output a few first bytes and then wait
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* for POSTDATA without closing stdout.
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* With full_read we may wait here forever. */
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count = safe_read(fromCgi_rd, rbuf + out_cnt, PIPE_BUF - 8);
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if (count <= 0) {
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/* eof (or error) and there was no "HTTP",
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* so write it, then write received data */
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if (out_cnt) {
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full_write(1, HTTP_200, sizeof(HTTP_200)-1);
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full_write(1, rbuf, out_cnt);
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}
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break; /* CGI stdout is closed, exiting */
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}
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out_cnt += count;
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count = 0;
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/* "Status" header format is: "Status: 302 Redirected\r\n" */
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if (out_cnt >= 8 && memcmp(rbuf, "Status: ", 8) == 0) {
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/* send "HTTP/1.0 " */
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if (full_write(1, HTTP_200, 9) != 9)
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break;
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rbuf += 8; /* skip "Status: " */
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count = out_cnt - 8;
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out_cnt = -1; /* buffering off */
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} else if (out_cnt >= 4) {
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/* Did CGI add "HTTP"? */
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if (memcmp(rbuf, HTTP_200, 4) != 0) {
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/* there is no "HTTP", do it ourself */
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if (full_write(1, HTTP_200, sizeof(HTTP_200)-1) != sizeof(HTTP_200)-1)
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break;
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}
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/* Commented out:
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if (!strstr(rbuf, "ontent-")) {
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full_write(s, "Content-type: text/plain\r\n\r\n", 28);
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}
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* Counter-example of valid CGI without Content-type:
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* echo -en "HTTP/1.0 302 Found\r\n"
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* echo -en "Location: http://www.busybox.net\r\n"
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* echo -en "\r\n"
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*/
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count = out_cnt;
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out_cnt = -1; /* buffering off */
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}
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} else {
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count = safe_read(fromCgi_rd, rbuf, PIPE_BUF);
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if (count <= 0)
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break; /* eof (or error) */
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}
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if (full_write(1, rbuf, count) != count)
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break;
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if (DEBUG)
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fprintf(stderr, "cgi read %d bytes: '%.*s'\n", count, count, rbuf);
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} /* if (pfd[FROM_CGI].revents) */
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} /* while (1) */
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log_and_exit();
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}
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static void setenv1(const char *name, const char *value)
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{
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setenv(name, value ? value : "", 1);
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@ -1038,25 +1208,25 @@ static void setenv1(const char *name, const char *value)
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* Spawn CGI script, forward CGI's stdin/out <=> network
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*
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* Environment variables are set up and the script is invoked with pipes
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* for stdin/stdout. If a post is being done the script is fed the POST
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* for stdin/stdout. If a POST is being done the script is fed the POST
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* data in addition to setting the QUERY_STRING variable (for GETs or POSTs).
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*
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* Parameters:
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* const char *url The requested URL (with leading /).
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* int bodyLen Length of the post body.
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* int post_len Length of the POST body.
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* const char *cookie For set HTTP_COOKIE.
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* const char *content_type For set CONTENT_TYPE.
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*/
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static void send_cgi_and_exit(
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const char *url,
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const char *request,
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int bodyLen,
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int post_len,
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const char *cookie,
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const char *content_type) ATTRIBUTE_NORETURN;
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static void send_cgi_and_exit(
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const char *url,
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const char *request,
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int bodyLen,
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int post_len,
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const char *cookie,
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const char *content_type)
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{
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@ -1065,9 +1235,7 @@ static void send_cgi_and_exit(
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char *fullpath;
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char *script;
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char *purl;
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int buf_count;
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int status;
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int pid = 0;
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int pid;
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/*
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* We are mucking with environment _first_ and then vfork/exec,
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@ -1138,8 +1306,8 @@ static void send_cgi_and_exit(
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}
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}
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setenv1("HTTP_USER_AGENT", user_agent);
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if (bodyLen)
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putenv(xasprintf("CONTENT_LENGTH=%d", bodyLen));
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if (post_len)
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putenv(xasprintf("CONTENT_LENGTH=%d", post_len));
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if (cookie)
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setenv1("HTTP_COOKIE", cookie);
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if (content_type)
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@ -1215,168 +1383,15 @@ static void send_cgi_and_exit(
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/* Parent process */
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/* First, restore variables possibly changed by child */
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/* Restore variables possibly changed by child */
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xfunc_error_retval = 0;
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/* Prepare for pumping data.
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* iobuf is used for CGI -> network data,
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* hdr_buf is for network -> CGI data (POSTDATA) */
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buf_count = 0;
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/* Pump data */
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close(fromCgi.wr);
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close(toCgi.rd);
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/* If CGI dies, we still want to correctly finish reading its output
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* and send it to the peer. So please no SIGPIPEs! */
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signal(SIGPIPE, SIG_IGN);
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/* This loop still looks messy. What is an exit criteria?
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* "CGI's output closed"? Or "CGI has exited"?
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* What to do if CGI has closed both input and output, but
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* didn't exit? etc... */
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/* NB: breaking out of this loop jumps to log_and_exit() */
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while (1) {
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fd_set readSet;
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fd_set writeSet;
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int nfound;
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int count;
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FD_ZERO(&readSet);
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FD_ZERO(&writeSet);
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FD_SET(fromCgi.rd, &readSet);
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if (bodyLen > 0 || hdr_cnt > 0) {
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FD_SET(toCgi.wr, &writeSet);
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nfound = toCgi.wr > fromCgi.rd ? toCgi.wr : fromCgi.rd;
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if (hdr_cnt <= 0)
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FD_SET(0, &readSet);
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/* Now wait on the set of sockets! */
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nfound = select(nfound + 1, &readSet, &writeSet, NULL, NULL);
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} else {
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if (!bodyLen) {
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close(toCgi.wr); /* no more POST data to CGI */
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bodyLen = -1;
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}
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nfound = select(fromCgi.rd + 1, &readSet, NULL, NULL, NULL);
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}
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if (nfound <= 0) {
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if (waitpid(pid, &status, WNOHANG) <= 0) {
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/* Weird. CGI didn't exit and no fd's
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* are ready, yet select returned?! */
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continue;
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}
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close(fromCgi.rd);
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if (DEBUG && WIFEXITED(status))
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bb_error_msg("CGI exited, status=%d", WEXITSTATUS(status));
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if (DEBUG && WIFSIGNALED(status))
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bb_error_msg("CGI killed, signal=%d", WTERMSIG(status));
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break;
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}
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if (hdr_cnt > 0 && FD_ISSET(toCgi.wr, &writeSet)) {
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/* Have data from peer and can write to CGI */
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count = safe_write(toCgi.wr, hdr_ptr, hdr_cnt);
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/* Doesn't happen, we dont use nonblocking IO here
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*if (count < 0 && errno == EAGAIN) {
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* ...
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*} else */
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if (count > 0) {
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hdr_ptr += count;
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hdr_cnt -= count;
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} else {
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hdr_cnt = bodyLen = 0; /* EOF/broken pipe to CGI */
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}
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} else if (bodyLen > 0 && hdr_cnt == 0
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&& FD_ISSET(0, &readSet)
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) {
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/* We expect data, prev data portion is eaten by CGI
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* and there *is* data to read from the peer
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* (POSTDATA?) */
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count = bodyLen > (int)sizeof(hdr_buf) ? (int)sizeof(hdr_buf) : bodyLen;
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count = safe_read(0, hdr_buf, count);
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if (count > 0) {
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hdr_cnt = count;
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hdr_ptr = hdr_buf;
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bodyLen -= count;
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} else {
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bodyLen = 0; /* closed */
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}
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}
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#define PIPESIZE PIPE_BUF
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#if PIPESIZE >= IOBUF_SIZE
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# error "PIPESIZE >= IOBUF_SIZE"
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#endif
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if (FD_ISSET(fromCgi.rd, &readSet)) {
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/* There is something to read from CGI */
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char *rbuf = iobuf;
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/* Are we still buffering CGI output? */
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if (buf_count >= 0) {
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/* HTTP_200[] has single "\r\n" at the end.
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* According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html,
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* CGI scripts MUST send their own header terminated by
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* empty line, then data. That's why we have only one
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* <cr><lf> pair here. We will output "200 OK" line
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* if needed, but CGI still has to provide blank line
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* between header and body */
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/* Must use safe_read, not full_read, because
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* CGI may output a few first bytes and then wait
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* for POSTDATA without closing stdout.
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* With full_read we may wait here forever. */
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count = safe_read(fromCgi.rd, rbuf + buf_count, PIPESIZE - 8);
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if (count <= 0) {
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/* eof (or error) and there was no "HTTP",
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* so write it, then write received data */
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if (buf_count) {
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full_write(1, HTTP_200, sizeof(HTTP_200)-1);
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full_write(1, rbuf, buf_count);
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}
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break; /* CGI stdout is closed, exiting */
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}
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buf_count += count;
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count = 0;
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/* "Status" header format is: "Status: 302 Redirected\r\n" */
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if (buf_count >= 8 && memcmp(rbuf, "Status: ", 8) == 0) {
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/* send "HTTP/1.0 " */
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if (full_write(1, HTTP_200, 9) != 9)
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break;
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rbuf += 8; /* skip "Status: " */
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count = buf_count - 8;
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buf_count = -1; /* buffering off */
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} else if (buf_count >= 4) {
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/* Did CGI add "HTTP"? */
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if (memcmp(rbuf, HTTP_200, 4) != 0) {
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/* there is no "HTTP", do it ourself */
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if (full_write(1, HTTP_200, sizeof(HTTP_200)-1) != sizeof(HTTP_200)-1)
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break;
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}
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/* Commented out:
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if (!strstr(rbuf, "ontent-")) {
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full_write(s, "Content-type: text/plain\r\n\r\n", 28);
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}
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* Counter-example of valid CGI without Content-type:
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* echo -en "HTTP/1.0 302 Found\r\n"
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* echo -en "Location: http://www.busybox.net\r\n"
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* echo -en "\r\n"
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*/
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count = buf_count;
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buf_count = -1; /* buffering off */
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}
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} else {
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count = safe_read(fromCgi.rd, rbuf, PIPESIZE);
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if (count <= 0)
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break; /* eof (or error) */
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}
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if (full_write(1, rbuf, count) != count)
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break;
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if (DEBUG)
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fprintf(stderr, "cgi read %d bytes: '%.*s'\n", count, count, rbuf);
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} /* if (FD_ISSET(fromCgi.rd)) */
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} /* while (1) */
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log_and_exit();
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cgi_io_loop_and_exit(fromCgi.rd, toCgi.wr, post_len);
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}
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#endif /* FEATURE_HTTPD_CGI */
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/*
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