32a471e4d
Denis Vlasenko
2007-09-23
Subject
httpd: simplify CGI i/o loop. -200 bytes.
Binary
No binary (build failed)
Architecture & Compiler Flags
—
Build Log
(log yok)
Commit Diff GitHub →
networking/httpd.c+183 -168
| @@ -104,12 +104,15 @@ | |
| //#define DEBUG 1 | |
| #define DEBUG 0 | |
| + | #define IOBUF_SIZE 8192 /* IO buffer */ |
| + | |
| /* amount of buffering in a pipe */ | |
| #ifndef PIPE_BUF | |
| # define PIPE_BUF 4096 | |
| #endif | |
| - | |
| - | #define IOBUF_SIZE 8192 /* IO buffer */ |
| + | #if PIPE_BUF >= IOBUF_SIZE |
| + | # error "PIPE_BUF >= IOBUF_SIZE" |
| + | #endif |
| #define HEADER_READ_TIMEOUT 60 | |
| @@ -1029,6 +1032,173 @@ static int get_line(void) | |
| } | |
| #if ENABLE_FEATURE_HTTPD_CGI | |
| + | |
| + | /* gcc 4.2.1 fares better with NOINLINE */ |
| + | static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post_len) ATTRIBUTE_NORETURN; |
| + | static NOINLINE void cgi_io_loop_and_exit(int fromCgi_rd, int toCgi_wr, int post_len) |
| + | { |
| + | enum { FROM_CGI = 1, TO_CGI = 2 }; /* indexes in pfd[] */ |
| + | struct pollfd pfd[3]; |
| + | int out_cnt; /* we buffer a bit of initial CGI output */ |
| + | int count; |
| + | |
| + | /* iobuf is used for CGI -> network data, |
| + | * hdr_buf is for network -> CGI data (POSTDATA) */ |
| + | |
| + | /* If CGI dies, we still want to correctly finish reading its output |
| + | * and send it to the peer. So please no SIGPIPEs! */ |
| + | signal(SIGPIPE, SIG_IGN); |
| + | |
| + | /* NB: breaking out of this loop jumps to log_and_exit() */ |
| + | out_cnt = 0; |
| + | while (1) { |
| + | memset(pfd, 0, sizeof(pfd)); |
| + | |
| + | pfd[FROM_CGI].fd = fromCgi_rd; |
| + | pfd[FROM_CGI].events = POLLIN; |
| + | |
| + | if (toCgi_wr) { |
| + | pfd[TO_CGI].fd = toCgi_wr; |
| + | if (hdr_cnt > 0) { |
| + | pfd[TO_CGI].events = POLLOUT; |
| + | } else if (post_len > 0) { |
| + | pfd[0].events = POLLIN; |
| + | } else { |
| + | /* post_len <= 0 && hdr_cnt <= 0: |
| + | * no more POST data to CGI, |
| + | * let CGI see EOF on CGI's stdin */ |
| + | close(toCgi_wr); |
| + | toCgi_wr = 0; |
| + | } |
| + | } |
| + | |
| + | /* Now wait on the set of sockets */ |
| + | count = poll(pfd, 3, -1); |
| + | if (count <= 0) { |
| + | #if 0 |
| + | if (errno == EINTR) |
| + | continue; |
| + | #endif |
| + | #if 0 |
| + | if (waitpid(pid, &status, WNOHANG) <= 0) { |
| + | /* Weird. CGI didn't exit and no fd's |
| + | * are ready, yet poll returned?! */ |
| + | continue; |
| + | } |
| + | if (DEBUG && WIFEXITED(status)) |
| + | bb_error_msg("CGI exited, status=%d", WEXITSTATUS(status)); |
| + | if (DEBUG && WIFSIGNALED(status)) |
| + | bb_error_msg("CGI killed, signal=%d", WTERMSIG(status)); |
| + | #endif |
| + | break; |
| + | } |
| + | |
| + | if (pfd[TO_CGI].revents) { |
| + | /* hdr_cnt > 0 here due to the way pfd[TO_CGI].events set */ |
| + | /* Have data from peer and can write to CGI */ |
| + | count = safe_write(toCgi_wr, hdr_ptr, hdr_cnt); |
| + | /* Doesn't happen, we dont use nonblocking IO here |
| + | *if (count < 0 && errno == EAGAIN) { |
| + | * ... |
| + | *} else */ |
| + | if (count > 0) { |
| + | hdr_ptr += count; |
| + | hdr_cnt -= count; |
| + | } else { |
| + | /* EOF/broken pipe to CGI, stop piping POST data */ |
| + | hdr_cnt = post_len = 0; |
| + | } |
| + | } |
| + | |
| + | if (pfd[0].revents) { |
| + | /* post_len > 0 && hdr_cnt == 0 here */ |
| + | /* We expect data, prev data portion is eaten by CGI |
| + | * and there *is* data to read from the peer |
| + | * (POSTDATA) */ |
| + | //count = post_len > (int)sizeof(hdr_buf) ? (int)sizeof(hdr_buf) : post_len; |
| + | //count = safe_read(0, hdr_buf, count); |
| + | count = safe_read(0, hdr_buf, sizeof(hdr_buf)); |
| + | if (count > 0) { |
| + | hdr_cnt = count; |
| + | hdr_ptr = hdr_buf; |
| + | post_len -= count; |
| + | } else { |
| + | /* no more POST data can be read */ |
| + | post_len = 0; |
| + | } |
| + | } |
| + | |
| + | if (pfd[FROM_CGI].revents) { |
| + | /* There is something to read from CGI */ |
| + | char *rbuf = iobuf; |
| + | |
| + | /* Are we still buffering CGI output? */ |
| + | if (out_cnt >= 0) { |
| + | /* HTTP_200[] has single "\r\n" at the end. |
| + | * According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html, |
| + | * CGI scripts MUST send their own header terminated by |
| + | * empty line, then data. That's why we have only one |
| + | * <cr><lf> pair here. We will output "200 OK" line |
| + | * if needed, but CGI still has to provide blank line |
| + | * between header and body */ |
| + | |
| + | /* Must use safe_read, not full_read, because |
| + | * CGI may output a few first bytes and then wait |
| + | * for POSTDATA without closing stdout. |
| + | * With full_read we may wait here forever. */ |
| + | count = safe_read(fromCgi_rd, rbuf + out_cnt, PIPE_BUF - 8); |
| + | if (count <= 0) { |
| + | /* eof (or error) and there was no "HTTP", |
| + | * so write it, then write received data */ |
| + | if (out_cnt) { |
| + | full_write(1, HTTP_200, sizeof(HTTP_200)-1); |
| + | full_write(1, rbuf, out_cnt); |
| + | } |
| + | break; /* CGI stdout is closed, exiting */ |
| + | } |
| + | out_cnt += count; |
| + | count = 0; |
| + | /* "Status" header format is: "Status: 302 Redirected\r\n" */ |
| + | if (out_cnt >= 8 && memcmp(rbuf, "Status: ", 8) == 0) { |
| + | /* send "HTTP/1.0 " */ |
| + | if (full_write(1, HTTP_200, 9) != 9) |
| + | break; |
| + | rbuf += 8; /* skip "Status: " */ |
| + | count = out_cnt - 8; |
| + | out_cnt = -1; /* buffering off */ |
| + | } else if (out_cnt >= 4) { |
| + | /* Did CGI add "HTTP"? */ |
| + | if (memcmp(rbuf, HTTP_200, 4) != 0) { |
| + | /* there is no "HTTP", do it ourself */ |
| + | if (full_write(1, HTTP_200, sizeof(HTTP_200)-1) != sizeof(HTTP_200)-1) |
| + | break; |
| + | } |
| + | /* Commented out: |
| + | if (!strstr(rbuf, "ontent-")) { |
| + | full_write(s, "Content-type: text/plain\r\n\r\n", 28); |
| + | } |
| + | * Counter-example of valid CGI without Content-type: |
| + | * echo -en "HTTP/1.0 302 Found\r\n" |
| + | * echo -en "Location: http://www.busybox.net\r\n" |
| + | * echo -en "\r\n" |
| + | */ |
| + | count = out_cnt; |
| + | out_cnt = -1; /* buffering off */ |
| + | } |
| + | } else { |
| + | count = safe_read(fromCgi_rd, rbuf, PIPE_BUF); |
| + | if (count <= 0) |
| + | break; /* eof (or error) */ |
| + | } |
| + | if (full_write(1, rbuf, count) != count) |
| + | break; |
| + | if (DEBUG) |
| + | fprintf(stderr, "cgi read %d bytes: '%.*s'\n", count, count, rbuf); |
| + | } /* if (pfd[FROM_CGI].revents) */ |
| + | } /* while (1) */ |
| + | log_and_exit(); |
| + | } |
| + | |
| static void setenv1(const char *name, const char *value) | |
| { | |
| setenv(name, value ? value : "", 1); | |
| @@ -1038,25 +1208,25 @@ static void setenv1(const char *name, const char *value) | |
| * Spawn CGI script, forward CGI's stdin/out <=> network | |
| * | |
| * Environment variables are set up and the script is invoked with pipes | |
| - | * for stdin/stdout. If a post is being done the script is fed the POST |
| + | * for stdin/stdout. If a POST is being done the script is fed the POST |
| * data in addition to setting the QUERY_STRING variable (for GETs or POSTs). | |
| * | |
| * Parameters: | |
| * const char *url The requested URL (with leading /). | |
| - | * int bodyLen Length of the post body. |
| + | * int post_len Length of the POST body. |
| * const char *cookie For set HTTP_COOKIE. | |
| * const char *content_type For set CONTENT_TYPE. | |
| */ | |
| static void send_cgi_and_exit( | |
| const char *url, | |
| const char *request, | |
| - | int bodyLen, |
| + | int post_len, |
| const char *cookie, | |
| const char *content_type) ATTRIBUTE_NORETURN; | |
| static void send_cgi_and_exit( | |
| const char *url, | |
| const char *request, | |
| - | int bodyLen, |
| + | int post_len, |
| const char *cookie, | |
| const char *content_type) | |
| { | |
| @@ -1065,9 +1235,7 @@ static void send_cgi_and_exit( | |
| char *fullpath; | |
| char *script; | |
| char *purl; | |
| - | int buf_count; |
| - | int status; |
| - | int pid = 0; |
| + | int pid; |
| /* | |
| * We are mucking with environment _first_ and then vfork/exec, | |
| @@ -1138,8 +1306,8 @@ static void send_cgi_and_exit( | |
| } | |
| } | |
| setenv1("HTTP_USER_AGENT", user_agent); | |
| - | if (bodyLen) |
| - | putenv(xasprintf("CONTENT_LENGTH=%d", bodyLen)); |
| + | if (post_len) |
| + | putenv(xasprintf("CONTENT_LENGTH=%d", post_len)); |
| if (cookie) | |
| setenv1("HTTP_COOKIE", cookie); | |
| if (content_type) | |
| @@ -1215,168 +1383,15 @@ static void send_cgi_and_exit( | |
| /* Parent process */ | |
| - | /* First, restore variables possibly changed by child */ |
| + | /* Restore variables possibly changed by child */ |
| xfunc_error_retval = 0; | |
| - | /* Prepare for pumping data. |
| - | * iobuf is used for CGI -> network data, |
| - | * hdr_buf is for network -> CGI data (POSTDATA) */ |
| - | buf_count = 0; |
| + | /* Pump data */ |
| close(fromCgi.wr); | |
| close(toCgi.rd); | |
| - | |
| - | /* If CGI dies, we still want to correctly finish reading its output |
| - | * and send it to the peer. So please no SIGPIPEs! */ |
| - | signal(SIGPIPE, SIG_IGN); |
| - | |
| - | /* This loop still looks messy. What is an exit criteria? |
| - | * "CGI's output closed"? Or "CGI has exited"? |
| - | * What to do if CGI has closed both input and output, but |
| - | * didn't exit? etc... */ |
| - | |
| - | /* NB: breaking out of this loop jumps to log_and_exit() */ |
| - | while (1) { |
| - | fd_set readSet; |
| - | fd_set writeSet; |
| - | int nfound; |
| - | int count; |
| - | |
| - | FD_ZERO(&readSet); |
| - | FD_ZERO(&writeSet); |
| - | FD_SET(fromCgi.rd, &readSet); |
| - | if (bodyLen > 0 || hdr_cnt > 0) { |
| - | FD_SET(toCgi.wr, &writeSet); |
| - | nfound = toCgi.wr > fromCgi.rd ? toCgi.wr : fromCgi.rd; |
| - | if (hdr_cnt <= 0) |
| - | FD_SET(0, &readSet); |
| - | /* Now wait on the set of sockets! */ |
| - | nfound = select(nfound + 1, &readSet, &writeSet, NULL, NULL); |
| - | } else { |
| - | if (!bodyLen) { |
| - | close(toCgi.wr); /* no more POST data to CGI */ |
| - | bodyLen = -1; |
| - | } |
| - | nfound = select(fromCgi.rd + 1, &readSet, NULL, NULL, NULL); |
| - | } |
| - | |
| - | if (nfound <= 0) { |
| - | if (waitpid(pid, &status, WNOHANG) <= 0) { |
| - | /* Weird. CGI didn't exit and no fd's |
| - | * are ready, yet select returned?! */ |
| - | continue; |
| - | } |
| - | close(fromCgi.rd); |
| - | if (DEBUG && WIFEXITED(status)) |
| - | bb_error_msg("CGI exited, status=%d", WEXITSTATUS(status)); |
| - | if (DEBUG && WIFSIGNALED(status)) |
| - | bb_error_msg("CGI killed, signal=%d", WTERMSIG(status)); |
| - | break; |
| - | } |
| - | |
| - | if (hdr_cnt > 0 && FD_ISSET(toCgi.wr, &writeSet)) { |
| - | /* Have data from peer and can write to CGI */ |
| - | count = safe_write(toCgi.wr, hdr_ptr, hdr_cnt); |
| - | /* Doesn't happen, we dont use nonblocking IO here |
| - | *if (count < 0 && errno == EAGAIN) { |
| - | * ... |
| - | *} else */ |
| - | if (count > 0) { |
| - | hdr_ptr += count; |
| - | hdr_cnt -= count; |
| - | } else { |
| - | hdr_cnt = bodyLen = 0; /* EOF/broken pipe to CGI */ |
| - | } |
| - | } else if (bodyLen > 0 && hdr_cnt == 0 |
| - | && FD_ISSET(0, &readSet) |
| - | ) { |
| - | /* We expect data, prev data portion is eaten by CGI |
| - | * and there *is* data to read from the peer |
| - | * (POSTDATA?) */ |
| - | count = bodyLen > (int)sizeof(hdr_buf) ? (int)sizeof(hdr_buf) : bodyLen; |
| - | count = safe_read(0, hdr_buf, count); |
| - | if (count > 0) { |
| - | hdr_cnt = count; |
| - | hdr_ptr = hdr_buf; |
| - | bodyLen -= count; |
| - | } else { |
| - | bodyLen = 0; /* closed */ |
| - | } |
| - | } |
| - | |
| - | #define PIPESIZE PIPE_BUF |
| - | #if PIPESIZE >= IOBUF_SIZE |
| - | # error "PIPESIZE >= IOBUF_SIZE" |
| - | #endif |
| - | if (FD_ISSET(fromCgi.rd, &readSet)) { |
| - | /* There is something to read from CGI */ |
| - | char *rbuf = iobuf; |
| - | |
| - | /* Are we still buffering CGI output? */ |
| - | if (buf_count >= 0) { |
| - | /* HTTP_200[] has single "\r\n" at the end. |
| - | * According to http://hoohoo.ncsa.uiuc.edu/cgi/out.html, |
| - | * CGI scripts MUST send their own header terminated by |
| - | * empty line, then data. That's why we have only one |
| - | * <cr><lf> pair here. We will output "200 OK" line |
| - | * if needed, but CGI still has to provide blank line |
| - | * between header and body */ |
| - | |
| - | /* Must use safe_read, not full_read, because |
| - | * CGI may output a few first bytes and then wait |
| - | * for POSTDATA without closing stdout. |
| - | * With full_read we may wait here forever. */ |
| - | count = safe_read(fromCgi.rd, rbuf + buf_count, PIPESIZE - 8); |
| - | if (count <= 0) { |
| - | /* eof (or error) and there was no "HTTP", |
| - | * so write it, then write received data */ |
| - | if (buf_count) { |
| - | full_write(1, HTTP_200, sizeof(HTTP_200)-1); |
| - | full_write(1, rbuf, buf_count); |
| - | } |
| - | break; /* CGI stdout is closed, exiting */ |
| - | } |
| - | buf_count += count; |
| - | count = 0; |
| - | /* "Status" header format is: "Status: 302 Redirected\r\n" */ |
| - | if (buf_count >= 8 && memcmp(rbuf, "Status: ", 8) == 0) { |
| - | /* send "HTTP/1.0 " */ |
| - | if (full_write(1, HTTP_200, 9) != 9) |
| - | break; |
| - | rbuf += 8; /* skip "Status: " */ |
| - | count = buf_count - 8; |
| - | buf_count = -1; /* buffering off */ |
| - | } else if (buf_count >= 4) { |
| - | /* Did CGI add "HTTP"? */ |
| - | if (memcmp(rbuf, HTTP_200, 4) != 0) { |
| - | /* there is no "HTTP", do it ourself */ |
| - | if (full_write(1, HTTP_200, sizeof(HTTP_200)-1) != sizeof(HTTP_200)-1) |
| - | break; |
| - | } |
| - | /* Commented out: |
| - | if (!strstr(rbuf, "ontent-")) { |
| - | full_write(s, "Content-type: text/plain\r\n\r\n", 28); |
| - | } |
| - | * Counter-example of valid CGI without Content-type: |
| - | * echo -en "HTTP/1.0 302 Found\r\n" |
| - | * echo -en "Location: http://www.busybox.net\r\n" |
| - | * echo -en "\r\n" |
| - | */ |
| - | count = buf_count; |
| - | buf_count = -1; /* buffering off */ |
| - | } |
| - | } else { |
| - | count = safe_read(fromCgi.rd, rbuf, PIPESIZE); |
| - | if (count <= 0) |
| - | break; /* eof (or error) */ |
| - | } |
| - | if (full_write(1, rbuf, count) != count) |
| - | break; |
| - | if (DEBUG) |
| - | fprintf(stderr, "cgi read %d bytes: '%.*s'\n", count, count, rbuf); |
| - | } /* if (FD_ISSET(fromCgi.rd)) */ |
| - | } /* while (1) */ |
| - | log_and_exit(); |
| + | cgi_io_loop_and_exit(fromCgi.rd, toCgi.wr, post_len); |
| } | |
| + | |
| #endif /* FEATURE_HTTPD_CGI */ | |
| /* | |