/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

/*
 * Copyright (c) 2018, Joyent, Inc.
 */

/*
 * csplit - Context or line file splitter
 * Compile: cc -O -s -o csplit csplit.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <regexpr.h>
#include <signal.h>
#include <locale.h>
#include <libintl.h>

#define LAST    0LL
#define ERR     -1
#define FALSE   0
#define TRUE    1
#define EXPMODE 2
#define LINMODE 3
#define LINSIZ  LINE_MAX        /* POSIX.2 - read lines LINE_MAX long */

        /* Globals */

char linbuf[LINSIZ];            /* Input line buffer */
char *expbuf;
char tmpbuf[BUFSIZ];            /* Temporary buffer for stdin */
char file[8192] = "xx";         /* File name buffer */
char *targ;                     /* Arg ptr for error messages */
char *sptr;
FILE *infile, *outfile;         /* I/O file streams */
int silent, keep, create;       /* Flags: -s(ilent), -k(eep), (create) */
int errflg;
int fiwidth = 2;                /* file index width (output file names) */
extern int optind;
extern char *optarg;
offset_t offset;                /* Regular expression offset value */
offset_t curline;               /* Current line in input file */

/*
 * These defines are needed for regexp handling(see regexp(7))
 */
#define PERROR(x)       fatal("%s: Illegal Regular Expression\n", targ);

static int asc_to_ll(char *, long long *);
static void closefile(void);
static void fatal(char *, char *);
static offset_t findline(char *, offset_t);
static void flush(void);
static FILE *getfile(void);
static char *getaline(int);
static void line_arg(char *);
static void num_arg(char *, int);
static void re_arg(char *);
static void sig(int);
static void to_line(offset_t);
static void usage(void);

int
main(int argc, char **argv)
{
        int ch, mode;
        char *ptr;

        (void) setlocale(LC_ALL, "");
#if !defined(TEXT_DOMAIN)               /* Should be defined by cc -D */
#define TEXT_DOMAIN     "SYS_TEST"      /* Use this only if it weren't */
#endif
        (void) textdomain(TEXT_DOMAIN);

        while ((ch = getopt(argc, argv, "skf:n:")) != EOF) {
                switch (ch) {
                        case 'f':
                                (void) strcpy(file, optarg);
                                if ((ptr = strrchr(optarg, '/')) == NULL)
                                        ptr = optarg;
                                else
                                        ptr++;

                                break;
                        case 'n':               /* POSIX.2 */
                                for (ptr = optarg; *ptr != '\0'; ptr++)
                                        if (!isdigit((int)*ptr))
                                                fatal("-n num\n", NULL);
                                fiwidth = atoi(optarg);
                                break;
                        case 'k':
                                keep++;
                                break;
                        case 's':
                                silent++;
                                break;
                        case '?':
                                errflg++;
                }
        }

        argv = &argv[optind];
        argc -= optind;
        if (argc <= 1 || errflg)
                usage();

        if (strcmp(*argv, "-") == 0) {
                infile = tmpfile();

                while (fread(tmpbuf, 1, BUFSIZ, stdin) != 0) {
                        if (fwrite(tmpbuf, 1, BUFSIZ, infile) == 0)
                                if (errno == ENOSPC) {
                                        (void) fprintf(stderr, "csplit: ");
                                        (void) fprintf(stderr, gettext(
                                            "No space left on device\n"));
                                        exit(1);
                                } else {
                                        (void) fprintf(stderr, "csplit: ");
                                        (void) fprintf(stderr, gettext(
                                            "Bad write to temporary "
                                            "file\n"));
                                        exit(1);
                                }

        /* clear the buffer to get correct size when writing buffer */

                        (void) memset(tmpbuf, '\0', sizeof (tmpbuf));
                }
                rewind(infile);
        } else if ((infile = fopen(*argv, "r")) == NULL)
                fatal("Cannot open %s\n", *argv);
        ++argv;
        curline = (offset_t)1;
        (void) signal(SIGINT, sig);

        /*
         * The following for loop handles the different argument types.
         * A switch is performed on the first character of the argument
         * and each case calls the appropriate argument handling routine.
         */

        for (; *argv; ++argv) {
                targ = *argv;
                switch (**argv) {
                case '/':
                        mode = EXPMODE;
                        create = TRUE;
                        re_arg(*argv);
                        break;
                case '%':
                        mode = EXPMODE;
                        create = FALSE;
                        re_arg(*argv);
                        break;
                case '{':
                        num_arg(*argv, mode);
                        mode = FALSE;
                        break;
                default:
                        mode = LINMODE;
                        create = TRUE;
                        line_arg(*argv);
                        break;
                }
        }
        create = TRUE;
        to_line(LAST);
        return (0);
}

/*
 * asc_to_ll takes an ascii argument(str) and converts it to a long long(plc)
 * It returns ERR if an illegal character.  The reason that asc_to_ll
 * does not return an answer(long long) is that any value for the long
 * long is legal, and this version of asc_to_ll detects error strings.
 */

static int
asc_to_ll(char *str, long long *plc)
{
        int f;
        *plc = 0;
        f = 0;
        for (; ; str++) {
                switch (*str) {
                case ' ':
                case '\t':
                        continue;
                case '-':
                        f++;
                        /* FALLTHROUGH */
                case '+':
                        str++;
                }
                break;
        }
        for (; *str != '\0'; str++)
                if (*str >= '0' && *str <= '9')
                        *plc = *plc * 10 + *str - '0';
                else
                        return (ERR);
        if (f)
                *plc = -(*plc);
        return (TRUE);  /* not error */
}

/*
 * Closefile prints the byte count of the file created,(via fseeko
 * and ftello), if the create flag is on and the silent flag is not on.
 * If the create flag is on closefile then closes the file(fclose).
 */

static void
closefile()
{
        if (!silent && create) {
                (void) fseeko(outfile, (offset_t)0, SEEK_END);
                (void) fprintf(stdout, "%lld\n", (offset_t)ftello(outfile));
        }
        if (create)
                (void) fclose(outfile);
}

/*
 * Fatal handles error messages and cleanup.
 * Because "arg" can be the global file, and the cleanup processing
 * uses the global file, the error message is printed first.  If the
 * "keep" flag is not set, fatal unlinks all created files.  If the
 * "keep" flag is set, fatal closes the current file(if there is one).
 * Fatal exits with a value of 1.
 */

static void
fatal(char *string, char *arg)
{
        char *fls;
        int num;

        (void) fprintf(stderr, "csplit: ");

        /* gettext dynamically replaces string */

        (void) fprintf(stderr, gettext(string), arg);
        if (!keep) {
                if (outfile) {
                        (void) fclose(outfile);
                        for (fls = file; *fls != '\0'; fls++)
                                continue;
                        fls -= fiwidth;
                        for (num = atoi(fls); num >= 0; num--) {
                                (void) sprintf(fls, "%.*d", fiwidth, num);
                                (void) unlink(file);
                        }
                }
        } else
                if (outfile)
                        closefile();
        exit(1);
}

/*
 * Findline returns the line number referenced by the current argument.
 * Its arguments are a pointer to the compiled regular expression(expr),
 * and an offset(oset).  The variable lncnt is used to count the number
 * of lines searched.  First the current stream location is saved via
 * ftello(), and getaline is called so that R.E. searching starts at the
 * line after the previously referenced line.  The while loop checks
 * that there are more lines(error if none), bumps the line count, and
 * checks for the R.E. on each line.  If the R.E. matches on one of the
 * lines the old stream location is restored, and the line number
 * referenced by the R.E. and the offset is returned.
 */

static offset_t
findline(char *expr, offset_t oset)
{
        static int benhere = 0;
        offset_t lncnt = 0, saveloc;

        saveloc = ftello(infile);
        if (curline != (offset_t)1 || benhere)  /* If first line, first time, */
                (void) getaline(FALSE);         /* then don't skip */
        else
                lncnt--;
        benhere = 1;
        while (getaline(FALSE) != NULL) {
                lncnt++;
                if ((sptr = strrchr(linbuf, '\n')) != NULL)
                        *sptr = '\0';
                if (step(linbuf, expr)) {
                        (void) fseeko(infile, (offset_t)saveloc, SEEK_SET);
                        return (curline+lncnt+oset);
                }
        }
        (void) fseeko(infile, (offset_t)saveloc, SEEK_SET);
        return (curline+lncnt+oset+2);
}

/*
 * Flush uses fputs to put lines on the output file stream(outfile)
 * Since fputs does its own buffering, flush doesn't need to.
 * Flush does nothing if the create flag is not set.
 */

static void
flush()
{
        if (create)
                (void) fputs(linbuf, outfile);
}

/*
 * Getfile does nothing if the create flag is not set.  If the create
 * flag is set, getfile positions the file pointer(fptr) at the end of
 * the file name prefix on the first call(fptr=0).  The file counter is
 * stored in the file name and incremented.  If the subsequent fopen
 * fails, the file name is copied to tfile for the error message, the
 * previous file name is restored for cleanup, and fatal is called.  If
 * the fopen succeeds, the stream(opfil) is returned.
 */

FILE *
getfile()
{
        static char *fptr;
        static int ctr;
        FILE *opfil;
        char tfile[15];
        char *delim;
        char savedelim;

        if (create) {
                if (fptr == 0)
                        for (fptr = file; *fptr != '\0'; fptr++)
                                continue;
                (void) sprintf(fptr, "%.*d", fiwidth, ctr++);

                /* check for suffix length overflow */
                if (strlen(fptr) > fiwidth) {
                        fatal("Suffix longer than %ld chars; increase -n\n",
                            (char *)fiwidth);
                }

                /* check for filename length overflow */

                delim = strrchr(file, '/');
                if (delim == (char *)NULL) {
                        if (strlen(file) > pathconf(".", _PC_NAME_MAX)) {
                                fatal("Name too long: %s\n", file);
                        }
                } else {
                        /* truncate file at pathname delim to do pathconf */
                        savedelim = *delim;
                        *delim = '\0';
                        /*
                         * file: pppppppp\0fffff\0
                         * ..... ^ file
                         * ............. ^ delim
                         */
                        if (strlen(delim + 1) > pathconf(file, _PC_NAME_MAX)) {
                                fatal("Name too long: %s\n", delim + 1);
                        }
                        *delim = savedelim;
                }

                if ((opfil = fopen(file, "w")) == NULL) {
                        (void) strlcpy(tfile, file, sizeof (tfile));
                        (void) sprintf(fptr, "%.*d", fiwidth, (ctr-2));
                        fatal("Cannot create %s\n", tfile);
                }
                return (opfil);
        }
        return (NULL);
}

/*
 * Getline gets a line via fgets from the input stream "infile".
 * The line is put into linbuf and may not be larger than LINSIZ.
 * If getaline is called with a non-zero value, the current line
 * is bumped, otherwise it is not(for R.E. searching).
 */

static char *
getaline(int bumpcur)
{
        char *ret;
        if (bumpcur)
                curline++;
        ret = fgets(linbuf, LINSIZ, infile);
        return (ret);
}

/*
 * Line_arg handles line number arguments.
 * line_arg takes as its argument a pointer to a character string
 * (assumed to be a line number).  If that character string can be
 * converted to a number(long long), to_line is called with that number,
 * otherwise error.
 */

static void
line_arg(char *line)
{
        long long to;

        if (asc_to_ll(line, &to) == ERR)
                fatal("%s: bad line number\n", line);
        to_line(to);
}

/*
 * Num_arg handles repeat arguments.
 * Num_arg copies the numeric argument to "rep" (error if number is
 * larger than 20 characters or } is left off).  Num_arg then converts
 * the number and checks for validity.  Next num_arg checks the mode
 * of the previous argument, and applys the argument the correct number
 * of times. If the mode is not set properly its an error.
 */

static void
num_arg(char *arg, int md)
{
        offset_t repeat, toline;
        char rep[21];
        char *ptr;
        int             len;

        ptr = rep;
        for (++arg; *arg != '}'; arg += len) {
                if (*arg == '\0')
                        fatal("%s: missing '}'\n", targ);
                if ((len = mblen(arg, MB_LEN_MAX)) <= 0)
                        len = 1;
                if ((ptr + len) >= &rep[20])
                        fatal("%s: Repeat count too large\n", targ);
                (void) memcpy(ptr, arg, len);
                ptr += len;
        }
        *ptr = '\0';
        if ((asc_to_ll(rep, &repeat) == ERR) || repeat < 0L)
                fatal("Illegal repeat count: %s\n", targ);
        if (md == LINMODE) {
                toline = offset = curline;
                for (; repeat > 0LL; repeat--) {
                        toline += offset;
                        to_line(toline);
                }
        } else  if (md == EXPMODE)
                        for (; repeat > 0LL; repeat--)
                                to_line(findline(expbuf, offset));
                else
                        fatal("No operation for %s\n", targ);
}

/*
 * Re_arg handles regular expression arguments.
 * Re_arg takes a csplit regular expression argument.  It checks for
 * delimiter balance, computes any offset, and compiles the regular
 * expression.  Findline is called with the compiled expression and
 * offset, and returns the corresponding line number, which is used
 * as input to the to_line function.
 */

static void
re_arg(char *string)
{
        char *ptr;
        char ch;
        int             len;

        ch = *string;
        ptr = string;
        ptr++;
        while (*ptr != ch) {
                if (*ptr == '\\')
                        ++ptr;

                if (*ptr == '\0')
                        fatal("%s: missing delimiter\n", targ);

                if ((len = mblen(ptr, MB_LEN_MAX)) <= 0)
                        len = 1;
                ptr += len;
        }

        /*
         * The line below was added because compile no longer supports
         * the fourth argument being passed.  The fourth argument used
         * to be '/' or '%'.
         */

        *ptr = '\0';
        if (asc_to_ll(++ptr, &offset) == ERR)
                fatal("%s: illegal offset\n", string);

        /*
         * The line below was added because INIT which did this for us
         * was removed from compile in regexp.h
         */

        string++;
        expbuf = compile(string, (char *)0, (char *)0);
        if (regerrno)
                PERROR(regerrno);
        to_line(findline(expbuf, offset));
}

/*
 * Sig handles breaks.  When a break occurs the signal is reset,
 * and fatal is called to clean up and print the argument which
 * was being processed at the time the interrupt occured.
 */

/* ARGSUSED */
static void
sig(int s)
{
        (void) signal(SIGINT, sig);
        fatal("Interrupt - program aborted at arg '%s'\n", targ);
}

/*
 * To_line creates split files.
 * To_line gets as its argument the line which the current argument
 * referenced.  To_line calls getfile for a new output stream, which
 * does nothing if create is False.  If to_line's argument is not LAST
 * it checks that the current line is not greater than its argument.
 * While the current line is less than the desired line to_line gets
 * lines and flushes(error if EOF is reached).
 * If to_line's argument is LAST, it checks for more lines, and gets
 * and flushes lines till the end of file.
 * Finally, to_line calls closefile to close the output stream.
 */

static void
to_line(offset_t ln)
{
        outfile = getfile();
        if (ln != LAST) {
                if (curline > ln)
                        fatal("%s - out of range\n", targ);
                while (curline < ln) {
                        if (getaline(TRUE) == NULL)
                                fatal("%s - out of range\n", targ);
                        flush();
                }
        } else          /* last file */
                if (getaline(TRUE) != NULL) {
                        flush();
                        for (;;) {
                                if (getaline(TRUE) == NULL)
                                        break;
                                flush();
                        }
                } else
                        fatal("%s - out of range\n", targ);
        closefile();
}

static void
usage()
{
        (void) fprintf(stderr, gettext(
            "usage: csplit [-ks] [-f prefix] [-n number] "
            "file arg1 ...argn\n"));
        exit(1);
}