/* vi: set sw=4 ts=4: */
/*
 * bare bones version of lpr & lpq: BSD printing utilities
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Original idea and code:
 *      Walter Harms <WHarms@bfs.de>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 *
 * See RFC 1179 for protocol description.
 */
//config:config LPR
//config:       bool "lpr"
//config:       default y
//config:       help
//config:         lpr sends files (or standard input) to a print spooling daemon.
//config:
//config:config LPQ
//config:       bool "lpq"
//config:       default y
//config:       help
//config:         lpq is a print spool queue examination and manipulation program.

//applet:IF_LPQ(APPLET_ODDNAME(lpq, lpqr, BB_DIR_USR_BIN, BB_SUID_DROP, lpq))
//applet:IF_LPR(APPLET_ODDNAME(lpr, lpqr, BB_DIR_USR_BIN, BB_SUID_DROP, lpr))

//kbuild:lib-$(CONFIG_LPR) += lpr.o
//kbuild:lib-$(CONFIG_LPQ) += lpr.o

//usage:#define lpr_trivial_usage
//usage:       "-P queue[@host[:port]] -U USERNAME -J TITLE -Vmh [FILE]..."
/* -C CLASS exists too, not shown.
 * CLASS is supposed to be printed on banner page, if one is requested */
//usage:#define lpr_full_usage "\n\n"
//usage:       "        -P      lp service to connect to (else uses $PRINTER)"
//usage:     "\n        -m      Send mail on completion"
//usage:     "\n        -h      Print banner page too"
//usage:     "\n        -V      Verbose"
//usage:
//usage:#define lpq_trivial_usage
//usage:       "[-P queue[@host[:port]]] [-U USERNAME] [-d JOBID]... [-fs]"
//usage:#define lpq_full_usage "\n\n"
//usage:       "        -P      lp service to connect to (else uses $PRINTER)"
//usage:     "\n        -d      Delete jobs"
//usage:     "\n        -f      Force any waiting job to be printed"
//usage:     "\n        -s      Short display"

#include "libbb.h"

/*
 * LPD returns binary 0 on success.
 * Otherwise it returns error message.
 */
static void get_response_or_say_and_die(int fd, const char *errmsg)
{
        ssize_t sz;
        char buf[128];

        buf[0] = ' ';
        sz = safe_read(fd, buf, 1);
        if ('\0' != buf[0]) {
                // request has failed
                // try to make sure last char is '\n', but do not add
                // superfluous one
                sz = full_read(fd, buf + 1, 126);
                bb_error_msg("error while %s%s", errmsg,
                                (sz > 0 ? ". Server said:" : ""));
                if (sz > 0) {
                        // sz = (bytes in buf) - 1
                        if (buf[sz] != '\n')
                                buf[++sz] = '\n';
                        safe_write(STDERR_FILENO, buf, sz + 1);
                }
                xfunc_die();
        }
}

int lpqr_main(int argc, char *argv[]) MAIN_EXTERNALLY_VISIBLE;
int lpqr_main(int argc UNUSED_PARAM, char *argv[])
{
        enum {
                OPT_P           = 1 << 0, // -P queue[@host[:port]]. If no -P is given use $PRINTER, then "lp@localhost:515"
                OPT_U           = 1 << 1, // -U username

                LPR_V           = 1 << 2, // -V: be verbose
                LPR_h           = 1 << 3, // -h: want banner printed
                LPR_C           = 1 << 4, // -C class: job "class" (? supposedly printed on banner)
                LPR_J           = 1 << 5, // -J title: the job title for the banner page
                LPR_m           = 1 << 6, // -m: send mail back to user

                LPQ_SHORT_FMT   = 1 << 2, // -s: short listing format
                LPQ_DELETE      = 1 << 3, // -d: delete job(s)
                LPQ_FORCE       = 1 << 4, // -f: force waiting job(s) to be printed
        };
        char tempfile[sizeof("/tmp/lprXXXXXX")];
        const char *job_title;
        const char *printer_class = "";   // printer class, max 32 char
        const char *queue;                // name of printer queue
        const char *server = "localhost"; // server[:port] of printer queue
        char *hostname;
        // N.B. IMHO getenv("USER") can be way easily spoofed!
        const char *user = xuid2uname(getuid());
        unsigned job;
        unsigned opts;
        int fd;

        queue = getenv("PRINTER");
        if (!queue)
                queue = "lp";

        // parse options
        // TODO: set opt_complementary: s,d,f are mutually exclusive
        opts = getopt32(argv,
                (/*lp*/'r' == applet_name[2]) ? "P:U:VhC:J:m" : "P:U:sdf"
                , &queue, &user
                , &printer_class, &job_title
        );
        argv += optind;

        {
                // queue name is to the left of '@'
                char *s = strchr(queue, '@');
                if (s) {
                        // server name is to the right of '@'
                        *s = '\0';
                        server = s + 1;
                }
        }

        // do connect
        fd = create_and_connect_stream_or_die(server, 515);

        //
        // LPQ ------------------------
        //
        if (/*lp*/'q' == applet_name[2]) {
                char cmd;
                // force printing of every job still in queue
                if (opts & LPQ_FORCE) {
                        cmd = 1;
                        goto command;
                // delete job(s)
                } else if (opts & LPQ_DELETE) {
                        fdprintf(fd, "\x5" "%s %s", queue, user);
                        while (*argv) {
                                fdprintf(fd, " %s", *argv++);
                        }
                        bb_putchar('\n');
                // dump current jobs status
                // N.B. periodical polling should be achieved
                // via "watch -n delay lpq"
                // They say it's the UNIX-way :)
                } else {
                        cmd = (opts & LPQ_SHORT_FMT) ? 3 : 4;
 command:
                        fdprintf(fd, "%c" "%s\n", cmd, queue);
                        bb_copyfd_eof(fd, STDOUT_FILENO);
                }

                return EXIT_SUCCESS;
        }

        //
        // LPR ------------------------
        //
        if (opts & LPR_V)
                bb_error_msg("connected to server");

        job = getpid() % 1000;
        hostname = safe_gethostname();

        // no files given on command line? -> use stdin
        if (!*argv)
                *--argv = (char *)"-";

        fdprintf(fd, "\x2" "%s\n", queue);
        get_response_or_say_and_die(fd, "setting queue");

        // process files
        do {
                unsigned cflen;
                int dfd;
                struct stat st;
                char *c;
                char *remote_filename;
                char *controlfile;

                // if data file is stdin, we need to dump it first
                if (LONE_DASH(*argv)) {
                        strcpy(tempfile, "/tmp/lprXXXXXX");
                        dfd = xmkstemp(tempfile);
                        bb_copyfd_eof(STDIN_FILENO, dfd);
                        xlseek(dfd, 0, SEEK_SET);
                        *argv = (char*)bb_msg_standard_input;
                } else {
                        dfd = xopen(*argv, O_RDONLY);
                }

                st.st_size = 0; /* paranoia: fstat may theoretically fail */
                fstat(dfd, &st);

                /* Apparently, some servers are buggy and won't accept 0-sized jobs.
                 * Standard lpr works around it by refusing to send such jobs:
                 */
                if (st.st_size == 0) {
                        bb_error_msg("nothing to print");
                        continue;
                }

                /* "The name ... should start with ASCII "cfA",
                 * followed by a three digit job number, followed
                 * by the host name which has constructed the file."
                 * We supply 'c' or 'd' as needed for control/data file. */
                remote_filename = xasprintf("fA%03u%s", job, hostname);

                // create control file
                // TODO: all lines but 2 last are constants! How we can use this fact?
                controlfile = xasprintf(
                        "H" "%.32s\n" "P" "%.32s\n" /* H HOST, P USER */
                        "C" "%.32s\n" /* C CLASS - printed on banner page (if L cmd is also given) */
                        "J" "%.99s\n" /* J JOBNAME */
                        /* "class name for banner page and job name
                         * for banner page commands must precede L command" */
                        "L" "%.32s\n" /* L USER - print banner page, with given user's name */
                        "M" "%.32s\n" /* M WHOM_TO_MAIL */
                        "l" "d%.31s\n" /* l DATA_FILE_NAME ("dfAxxx") */
                        , hostname, user
                        , printer_class /* can be "" */
                        , ((opts & LPR_J) ? job_title : *argv)
                        , (opts & LPR_h) ? user : ""
                        , (opts & LPR_m) ? user : ""
                        , remote_filename
                );
                // delete possible "\nX\n" (that is, one-char) patterns
                c = controlfile;
                while ((c = strchr(c, '\n')) != NULL) {
                        if (c[1] && c[2] == '\n') {
                                overlapping_strcpy(c, c+2);
                        } else {
                                c++;
                        }
                }

                // send control file
                if (opts & LPR_V)
                        bb_error_msg("sending control file");
                /* "Acknowledgement processing must occur as usual
                 * after the command is sent." */
                cflen = (unsigned)strlen(controlfile);
                fdprintf(fd, "\x2" "%u c%s\n", cflen, remote_filename);
                get_response_or_say_and_die(fd, "sending control file");
                /* "Once all of the contents have
                 * been delivered, an octet of zero bits is sent as
                 * an indication that the file being sent is complete.
                 * A second level of acknowledgement processing
                 * must occur at this point." */
                full_write(fd, controlfile, cflen + 1); /* writes NUL byte too */
                get_response_or_say_and_die(fd, "sending control file");

                // send data file, with name "dfaXXX"
                if (opts & LPR_V)
                        bb_error_msg("sending data file");
                fdprintf(fd, "\x3" "%"OFF_FMT"u d%s\n", st.st_size, remote_filename);
                get_response_or_say_and_die(fd, "sending data file");
                if (bb_copyfd_size(dfd, fd, st.st_size) != st.st_size) {
                        // We're screwed. We sent less bytes than we advertised.
                        bb_error_msg_and_die("local file changed size?!");
                }
                write(fd, "", 1); // send ACK
                get_response_or_say_and_die(fd, "sending data file");

                // delete temporary file if we dumped stdin
                if (*argv == (char*)bb_msg_standard_input)
                        unlink(tempfile);

                // cleanup
                close(fd);
                free(remote_filename);
                free(controlfile);

                // say job accepted
                if (opts & LPR_V)
                        bb_error_msg("job accepted");

                // next, please!
                job = (job + 1) % 1000;
        } while (*++argv);

        return EXIT_SUCCESS;
}