diff options
Diffstat (limited to 'bwchat_cgi.c')
| -rw-r--r-- | bwchat_cgi.c | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/bwchat_cgi.c b/bwchat_cgi.c new file mode 100644 index 0000000..6ae0e04 --- /dev/null +++ b/bwchat_cgi.c @@ -0,0 +1,630 @@ +/** + @file bwchat_cgi.c + @brief bwchat CGI + @author defanor <defanor@thunix.net> + @date 2024 + @copyright MIT license +*/ + +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <libgen.h> +#include <fcntl.h> +#include <time.h> +#include <unistd.h> +#include <syslog.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <errno.h> +#include <sys/select.h> +#include <argp.h> + +#include "bwchat.h" + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif +#ifdef HAVE_FCGI +#include "fcgi_stdio.h" +#endif + +#define BOUNDARY_LENGTH 128 +#define FIELD_NAME_LENGTH 128 +#define FILENAME_LENGTH 128 + +enum form_data_parsing_state { + FORM_PARSE_START, + FORM_PARSE_DONE, + FORM_PARSE_FAIL, + FORM_PARSE_HEADER, + FORM_PARSE_DATA +}; + +enum param_read_state { + PARAM_READ_SEARCH, + PARAM_READ_FOUND_COLON, + PARAM_READ_FOUND_PARAM, + PARAM_READ_QUOTED, + PARAM_READ_UNQUOTED, + PARAM_READ_SKIP_QUOTED +}; + +/* Global state */ +int sock = -1; + +/* Settings */ +const char *upload_dir_url = "upload/"; +const char *js_url = "bwchat.js"; +const char *sock_path = "bwchat-socket"; +int log_stderr = 0; + +char *html_escape (char *dst, const char *src, size_t sz) { + size_t i, j; + for (i = 0, j = 0; (i < (sz - 1)) && (j < (sz - 1)); i++, j++) { + if (src[i] == '<') { + strncpy(dst + j, "<", sz - j); + j += 3; + } else if (src[i] == '>') { + strncpy(dst + j, ">", sz - j); + j += 3; + } else if (src[i] == '"') { + strncpy(dst + j, """, sz - j); + j += 5; + } else if (src[i] == '&') { + strncpy(dst + j, "&", sz - j); + j += 4; + } else { + dst[j] = src[i]; + } + } + dst[j] = '\0'; + return dst; +} + +/* + https://www.rfc-editor.org/rfc/rfc822 -- Internet text messages + https://www.rfc-editor.org/rfc/rfc2183 -- Content-Disposition + https://www.rfc-editor.org/rfc/rfc7578 -- multipart/form-data +*/ +char *read_param (const char *line, const char *name, char *dst, size_t sz) { + size_t i, j; + size_t line_len = strlen(line); + size_t name_len = strlen(name); + enum param_read_state s = PARAM_READ_SEARCH; + dst[0] = '\0'; + for (i = 0, j = 0; i < line_len && j < sz; i++) { + if (s == PARAM_READ_SEARCH) { + if (line[i] == ';') { + s = PARAM_READ_FOUND_COLON; + } else if (line[i] == '"') { + s = PARAM_READ_SKIP_QUOTED; + } + } else if (s == PARAM_READ_FOUND_COLON && line[i] != ' ') { + if (i + name_len + 1 < line_len && + strncmp(line + i, name, name_len) == 0 && + line[i + name_len] == '=') { + s = PARAM_READ_FOUND_PARAM; + i += name_len; + } + } else if (s == PARAM_READ_FOUND_PARAM) { + if (line[i] == '"') { + s = PARAM_READ_QUOTED; + } else { + s = PARAM_READ_UNQUOTED; + dst[j] = line[i]; + j++; + } + } else if (s == PARAM_READ_SKIP_QUOTED) { + if (line[i] == '\\') { + i++; + } else if (line[i] == '"') { + s = PARAM_READ_SEARCH; + } + } else if (s == PARAM_READ_UNQUOTED) { + if (line[i] == '\r' || line[i] == '\n' || + line[i] == ';' || line[i] == ' ') { + dst[j] = '\0'; + return dst; + } + dst[j] = line[i]; + j++; + } else if (s == PARAM_READ_QUOTED) { + if (line[i] == '\\') { + i++; + } else if (line[i] == '"') { + dst[j] = '\0'; + return dst; + } + dst[j] = line[i]; + j++; + } + } + if (j > 0) { + dst[j] = '\0'; + return dst; + } + return NULL; +} + + +/* Reads data until a given substring is found. Aims successive calls, + to read data in chunks. The zero byte is inserted after the data, + making it suitable for textual data reading. */ +int read_till (const char *end, + char *out, + size_t out_buf_len, + size_t *out_data_len, + size_t *matched) +{ + size_t end_len = strlen(end); + + /* Check for a previous iteration's leftover, move it. */ + if (*out_data_len > 0) { + memmove(out, out + *out_data_len, *matched); + *out_data_len = 0; + } + + while (*out_data_len + *matched < out_buf_len) { + int c = getchar(); + if (c == -1) { + return -1; + } + out[*out_data_len + *matched] = c; + if (out[*out_data_len + *matched] == end[*matched]) { + /* Extending the match */ + *matched = *matched + 1; + } else { + /* Not matching: find the new matching prefix */ + *out_data_len = *out_data_len + 1; + while (*matched > 0 && + strncmp(out + *out_data_len, end, *matched) != 0) { + *matched = *matched - 1; + *out_data_len = *out_data_len + 1; + } + } + + /* Found the match */ + if (end_len == *matched) { + out[*out_data_len] = '\0'; + return 0; + } + } + /* Not found yet: the caller should consume the read bytes and keep + iterating. */ + return 1; +} + + +int sock_conn() { + struct sockaddr_un addr; + socklen_t addr_size; + sock = socket(AF_UNIX, SOCK_SEQPACKET, 0); + if (sock < 0) { + return -1; + } + addr.sun_family = AF_UNIX; + strncpy(addr.sun_path, sock_path, sizeof(addr.sun_path) - 1); + addr_size = sizeof(struct sockaddr_un); + if (connect(sock, (struct sockaddr *) &addr, addr_size) < 0) { + return -1; + } + return sock; +} + +int print_message (struct bwchat_message *msg) { + char nick[BWC_NICK_LENGTH]; + char message[BWC_MESSAGE_LENGTH]; + struct tm *btime; + + if (msg->type == BWC_MESSAGE_NONE) { + return 0; + } + btime = localtime(&(msg->timestamp)); + strftime(message, BWC_MESSAGE_LENGTH, "%H:%M", btime); + html_escape(nick, msg->nick, BWC_NICK_LENGTH); + if (printf(" <div>%s <b>%s</b>: ", message, nick) < 0) { + return -1; + } + if (msg->type == BWC_MESSAGE_TEXT) { + html_escape(message, msg->data, BWC_MESSAGE_LENGTH); + if (printf("%s", message) < 0) { + return -1; + } + } else if (msg->type == BWC_MESSAGE_UPLOAD) { + html_escape(message, msg->data, BWC_MESSAGE_LENGTH); + if (printf("<a href=\"%s%s\">%s</a>", upload_dir_url, + message, message) < 0) { + return -1; + } + } else if (msg->type == BWC_MESSAGE_AUDIO) { + if (printf + ("<audio controls=\"\" preload=\"none\" src=\"stream?%s\"></audio>", + nick) < 0) { + return -1; + } + } + if (puts("</div>") < 0) { + return -1; + } + return 0; +} + +int print_messages () { + struct bwchat_message msg; + ssize_t len; + char c = BWC_CMD_ALL_MESSAGES; + if (printf(" <div id=\"messages\">\n") < 0) { + return -1; + } + write(sock, &c, 1); + while (1) { + len = read(sock, &msg, sizeof(msg)); + if (len == 0) { + break; + } + if (len < (ssize_t)sizeof(msg)) { + return -1; + } + if (print_message(&msg) != 0) { + return -1; + } + } + if (printf(" </div>\n") < 0) { + return -1; + } + return 0; +} + + +int serve_messages () { + fd_set rset; + struct timeval timeout; + struct bwchat_message msg; + char c = BWC_CMD_NEW_MESSAGES; + int ret; + if (printf("Content-type: text/html\r\n" + "Cache-Control: no-cache\r\n" + "X-Accel-Buffering: no\r\n" + "\r\n") < 0) { + return -1; + } + write(sock, &c, 1); + + while (1) { + timeout.tv_sec = 10; + timeout.tv_usec = 0; + FD_ZERO(&rset); + FD_SET(sock, &rset); + ret = select(sock + 1, &rset, NULL, NULL, &timeout); + if (ret == 0) { + /* Timeout, send a ping. Primarily to see if the client is still + there, though it would also let the client know that the + connection is live, and possibly help to avoid gateway + timeouts. */ + if (puts("") < 0) { + break; + } + } else if (ret == 1) { + /* Input available */ + if (read(sock, &msg, sizeof(msg)) != sizeof(msg)) { + syslog(LOG_WARNING, "serve_messages: bwchat-server is gone"); + return 0; + } + if (print_message(&msg) != 0) { + break; + } + } else if (ret == -1) { + /* Error */ + syslog(LOG_ERR, "select() error in serve_messages"); + break; + } + if (fflush(stdout) < 0) { + break; + } + } + syslog(LOG_DEBUG, "a message listener is gone"); + return 0; +} + +int serve_stream () { + fd_set rset; + struct timeval timeout; + char *query_string = getenv("QUERY_STRING"); + char buf[BWC_MESSAGE_LENGTH]; + size_t len; + int ret; + buf[0] = BWC_CMD_AUDIO_STREAM; + strncpy(buf + 1, query_string, BWC_NICK_LENGTH); + write(sock, buf, BWC_NICK_LENGTH + 1); + + /* Send HTTP headers */ + printf("Content-type: audio/ogg\r\n" + "Cache-Control: no-cache\r\n" + "X-Accel-Buffering: no\r\n" + "\r\n"); + + /* Wait for new stream chunks, pass them to the client */ + while (1) { + timeout.tv_sec = 10; + timeout.tv_usec = 0; + FD_ZERO(&rset); + FD_SET(sock, &rset); + ret = select(sock + 1, &rset, NULL, NULL, &timeout); + if (ret != 1) { + /* Timeout or error: break. */ + break; + } + len = read(sock, &buf, sizeof(buf)); + if (len <= 0) { + syslog(LOG_WARNING, "serve_stream: bwchat-server is gone"); + return 0; + } + if (fwrite(buf, 1, len, stdout) < len) { + break; + } + if (fflush(stdout) < 0) { + break; + } + } + syslog(LOG_DEBUG, "an audio stream listener is gone"); + return 0; +} + +int handle_chat () { + size_t message_len = 0, matched = 0, len = 0; + enum form_data_parsing_state ps = FORM_PARSE_START; + char + *request_method = getenv("REQUEST_METHOD"), + *content_type = getenv("CONTENT_TYPE"), + message[BWC_MESSAGE_LENGTH + BOUNDARY_LENGTH + 4] = "\0", + nick[BWC_NICK_LENGTH + BOUNDARY_LENGTH + 4] = "\0", + filename[FILENAME_LENGTH] = "\0", + boundary[BOUNDARY_LENGTH + 4], + field_name[FIELD_NAME_LENGTH], + buf[4096]; + int stream = 0; + + if (strcmp(request_method, "POST") == 0) { + if (content_type != NULL && + strncmp(content_type, "multipart/form-data;", 20) == 0) { + /* Parse form data: nick, message, file, stream */ + strcpy(boundary, "\r\n--"); + read_param(content_type, "boundary", + boundary + 4, BOUNDARY_LENGTH - 2); + if (read_till(boundary + 2, buf, 4096, &len, &matched) != 0) { + syslog(LOG_ERR, "No initial boundary found"); + ps = FORM_PARSE_FAIL; + } + while (ps != FORM_PARSE_FAIL && ps != FORM_PARSE_DONE) { + len = 0; + matched = 0; + if (ps == FORM_PARSE_START) { + if (read_till("\r\n", buf, 4096, &len, &matched) == 0) { + if (len == 0) { + ps = FORM_PARSE_HEADER; + } else if (len == 2 && strcmp(buf, "--") == 0) { + ps = FORM_PARSE_DONE; + } + } else { + syslog(LOG_ERR, "Failed to start parsing"); + ps = FORM_PARSE_FAIL; + } + } else if (ps == FORM_PARSE_HEADER) { + if (read_till("\r\n", buf, 4096, &len, &matched) == 0) { + if (strncmp(buf, "Content-Disposition: form-data;", 31) == 0) { + read_param(buf, "name", field_name, FIELD_NAME_LENGTH); + read_param(buf, "filename", filename, FILENAME_LENGTH); + } else if (len == 0) { + ps = FORM_PARSE_DATA; + } + } else { + syslog(LOG_ERR, "Failed to parse a header"); + ps = FORM_PARSE_FAIL; + } + } else if (ps == FORM_PARSE_DATA) { + if (strcmp(field_name, "nick") == 0) { + if (read_till(boundary, nick, + BWC_NICK_LENGTH + BOUNDARY_LENGTH + 4, + &len, &matched) == 0) { + ps = FORM_PARSE_START; + } else { + syslog(LOG_ERR, "No boundary after nick"); + ps = FORM_PARSE_FAIL; + } + } else if (strcmp(field_name, "message") == 0) { + if (read_till(boundary, message, + BWC_MESSAGE_LENGTH + BOUNDARY_LENGTH + 4, + &message_len, &matched) == 0) { + ps = FORM_PARSE_START; + } else { + syslog(LOG_ERR, "No boundary after message"); + ps = FORM_PARSE_FAIL; + } + } else if (strcmp(field_name, "file") == 0 && + filename[0] != '\0') { + FILE *f = fopen(basename(filename), "w"); + if (f == NULL) { + syslog(LOG_ERR, "Failed to open a file: %s", strerror(errno)); + } else { + int r; + do { + r = read_till(boundary, buf, 4096, &len, &matched); + if (r >= 0) { + if (fwrite(buf, 1, len, f) < len) { + syslog(LOG_ERR, "Failed to write into a file: %s", + strerror(errno)); + break; + } + } else { + syslog(LOG_ERR, "No boundary after file contents"); + } + } while (r > 0); + if (fclose(f) != 0) { + syslog(LOG_ERR, "Failed to close a file: %s", strerror(errno)); + } + } + ps = FORM_PARSE_START; + } else if (strcmp(field_name, "stream") == 0) { + if (read_till(boundary, buf, 4096, &len, &matched) == 0) { + stream = 1; + ps = FORM_PARSE_START; + } else { + syslog(LOG_ERR, "No boundary after stream"); + ps = FORM_PARSE_FAIL; + } + } else { + /* Skip unknown fields */ + while (read_till(boundary, buf, 4096, &len, &matched) > 0); + ps = FORM_PARSE_START; + } + } + } + + /* Process the parsed form data */ + if (nick[0] != '\0') { + char buf[sizeof(struct bwchat_message) + 1]; + struct bwchat_message *msg = (struct bwchat_message *)(buf + 1); + time(&(msg->timestamp)); + strncpy(msg->nick, nick, BWC_NICK_LENGTH); + msg->nick[sizeof(msg->nick) - 1] = '\0'; + buf[0] = BWC_CMD_ADD_MESSAGE; + if (stream && message_len > 0) { + /* A chunk of stream */ + msg->type = BWC_MESSAGE_AUDIO; + msg->data_len = message_len; + memcpy(msg->data, message, BWC_MESSAGE_LENGTH); + len = write(sock, buf, sizeof(buf)); + } else if (message[0] != '\0' || filename[0] != '\0') { + /* A new message: either textual or file upload. */ + if (message[0] != '\0') { + /* New text message */ + msg->type = BWC_MESSAGE_TEXT; + strncpy(msg->data, message, BWC_MESSAGE_LENGTH); + msg->data[sizeof(msg->data) - 1] = '\0'; + } else if (filename[0] != '\0') { + /* New file upload message */ + msg->type = BWC_MESSAGE_UPLOAD; + strncpy(msg->data, filename, FILENAME_LENGTH); + } + msg->data_len = strlen(msg->data); + if (write(sock, buf, sizeof(buf)) != sizeof(buf)) { + syslog(LOG_ERR, "Failed to submit a new message: %s", + strerror(errno)); + } + /* Reopen the socket, since we will request messages after. */ + if (close(sock) < 0) { + syslog(LOG_ERR, "Socket closing error: %s", strerror(errno)); + } + if (sock_conn() < 0) { + syslog(LOG_ERR, "Failed to reconnect to the chat server: %s", + strerror(errno)); + return -1; + } + } + } + } + } + + /* Send a response to the client */ + if (stream) { + printf("Content-type: text/html\r\n" + "\r\n"); + } else { + printf + ("Content-type: text/html\r\n" + "\r\n" + "<!DOCTYPE html>\n" + "<html>\n" + " <head>\n" + " <title>Chat</title>\n" + " <script src=\"%s\"></script>\n" + " </head>\n" + " <body>\n", + js_url); + print_messages(); + printf + (" <form id=\"chatInputForm\" method=\"post\"" + " enctype=\"multipart/form-data\" >\n" + " <input type=\"text\" name=\"nick\" value=\"%s\" />\n" + " <input type=\"text\" name=\"message\" autofocus=\"\"" + " size=\"60\" />\n" + " <input type=\"file\" name=\"file\" />\n" + " <input type=\"submit\" />\n" + " </form>\n" + " </body>\n" + "</html>\n", + (nick[0] != '\0') ? nick : "Anonymous"); + } + return 0; +} + +static struct argp_option options[] = { + {"js-url", 'j', "URL", 0, + "JavaScript (bwchat.js) URL to reference from HTML", 0 }, + {"log-stderr", 'l', 0, 0, + "Write logs into stderr, in addition to syslog", 0 }, + {"socket-path", 's', "PATH", 0, + "The bwchat-server's Unix domain socket path", 0 }, + {"upload-dir-url", 'u', "URL", 0, + "The URL to use in hyperlinks", 0 }, + { 0 } +}; +static error_t parse_opt (int key, char *arg, struct argp_state *state) { + (void)state; + switch (key) { + case 'u': + upload_dir_url = arg; + break; + case 'j': + js_url = arg; + break; + case 's': + sock_path = arg; + break; + case 'l': + log_stderr = LOG_PERROR; + break; + default: + return ARGP_ERR_UNKNOWN; + } + return 0; +} +static struct argp argp = + { options, parse_opt, 0, "A basic web chat, the CGI program", 0, 0, 0 }; + +int main (int argc, char **argv) { + argp_parse(&argp, argc, argv, 0, 0, 0); + openlog("bwchat-cgi", LOG_PID | log_stderr, 0); + +#ifdef HAVE_FCGI + while (FCGI_Accept() >= 0) { +#endif + char *script_name, *script_bname; + if (sock_conn() < 0) { + syslog(LOG_DEBUG, + "Failed to connect to the chat server at %s: %s", + sock_path, strerror(errno)); +#ifdef HAVE_FCGI + continue; +#else + return -1; +#endif + } + script_name = getenv("SCRIPT_NAME"); + script_bname = basename(script_name); + if (strcmp(script_bname, "stream") == 0) { + serve_stream(); + } else if (strcmp(script_bname, "messages") == 0) { + serve_messages(); + } else { + handle_chat(); + } + if (close(sock) < 0) { + syslog(LOG_ERR, "Socket closing error: %s", strerror(errno)); + } +#ifdef HAVE_FCGI + } +#endif + return 0; +} |