/*
 * $OpenBSD: inp.c,v 1.34 2006/03/11 19:41:30 otto Exp $
 * $DragonFly: src/usr.bin/patch/inp.c,v 1.6 2007/09/29 23:11:10 swildner Exp $
 * $NetBSD: inp.c,v 1.30 2023/06/16 23:36:26 wiz Exp $
 */

/*
 * patch - a program to apply diffs to original files
 *
 * Copyright 1986, Larry Wall
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following condition is met:
 * 1. Redistributions of source code must retain the above copyright notice,
 * this condition and the following disclaimer.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * -C option added in 1998, original code by Marc Espie, based on FreeBSD
 * behaviour
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: inp.c,v 1.30 2023/06/16 23:36:26 wiz Exp $");

#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/wait.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "util.h"
#include "pch.h"
#include "inp.h"


/* Input-file-with-indexable-lines abstract type */

static off_t    i_size;         /* size of the input file */
static char     *i_womp;        /* plan a buffer for entire file */
static char     **i_ptr;        /* pointers to lines in i_womp */
static char     empty_line[] = { '\0' };

static int      tifd = -1;      /* plan b virtual string array */
static char     *tibuf[2];      /* plan b buffers */
static LINENUM  tiline[2] = {-1, -1};   /* 1st line in each buffer */
static LINENUM  lines_per_buf;  /* how many lines per buffer */
static int      tireclen;       /* length of records in tmp file */

static bool     rev_in_string(const char *);
static bool     reallocate_lines(size_t *);

/* returns false if insufficient memory */
static bool     plan_a(const char *);

static void     plan_b(const char *);

/* New patch--prepare to edit another file. */

void
re_input(void)
{
        if (using_plan_a) {
                i_size = 0;
                free(i_ptr);
                i_ptr = NULL;
                if (i_womp != NULL) {
                        munmap(i_womp, i_size);
                        i_womp = NULL;
                }
        } else {
                using_plan_a = true;    /* maybe the next one is smaller */
                close(tifd);
                tifd = -1;
                free(tibuf[0]);
                free(tibuf[1]);
                tibuf[0] = tibuf[1] = NULL;
                tiline[0] = tiline[1] = -1;
                tireclen = 0;
        }
}

/* Construct the line index, somehow or other. */

void
scan_input(const char *filename)
{
        if (!plan_a(filename))
                plan_b(filename);
        if (verbose) {
                say("Patching file %s using Plan %s...\n", filename,
                    (using_plan_a ? "A" : "B"));
        }
}

static bool
reallocate_lines(size_t *lines_allocated)
{
        char    **p;
        size_t  new_size;

        new_size = *lines_allocated * 3 / 2;
        p = pch_realloc(i_ptr, new_size + 2,  sizeof(char *));
        if (p == NULL) {        /* shucks, it was a near thing */
                munmap(i_womp, i_size);
                i_womp = NULL;
                free(i_ptr);
                i_ptr = NULL;
                *lines_allocated = 0;
                return false;
        }
        *lines_allocated = new_size;
        i_ptr = p;
        return true;
}

/* Try keeping everything in memory. */

static bool
plan_a(const char *filename)
{
        int             ifd, statfailed, devnull, pstat;
        char            *p, *s, *lbuf;
        struct stat     filestat;
        off_t           i;
        ptrdiff_t       sz;
        size_t          iline, lines_allocated, lbufsz;
        pid_t           pid;
        char            *argp[4] = {NULL};

#ifdef DEBUGGING
        if (debug & 8)
                return false;
#endif

        if (filename == NULL || *filename == '\0')
                return false;

        statfailed = stat(filename, &filestat);
        if (statfailed && ok_to_create_file) {
                if (verbose)
                        say("(Creating file %s...)\n", filename);

                /*
                 * in check_patch case, we still display `Creating file' even
                 * though we're not. The rule is that -C should be as similar
                 * to normal patch behavior as possible
                 */
                if (check_only)
                        return true;
                makedirs(filename, true);
                close(creat(filename, 0666));
                statfailed = stat(filename, &filestat);
        }
        if (statfailed && check_only)
                fatal("%s not found, -C mode, can't probe further\n", filename);
        /* For nonexistent or read-only files, look for RCS versions.  */
        if (statfailed ||
            /* No one can write to it.  */
            (filestat.st_mode & 0222) == 0 ||
            /* I can't write to it.  */
            ((filestat.st_mode & 0022) == 0 && filestat.st_uid != getuid())) {
                char    *filebase, *filedir;
                struct stat     cstat;
                char *tmp_filename1, *tmp_filename2;

                tmp_filename1 = strdup(filename);
                tmp_filename2 = strdup(filename);
                if (tmp_filename1 == NULL || tmp_filename2 == NULL)
                        fatal("strdupping filename");

                filebase = basename(tmp_filename1);
                filedir = dirname(tmp_filename2);

                lbufsz = INITLINELEN;
                if ((lbuf = malloc(bufsz)) == NULL)
                        pfatal("allocating line buffer");
                lbuf[0] = '\0';

#define try(f, a1, a2, a3) \
        (snprintf(lbuf, lbufsz, f, a1, a2, a3), stat(lbuf, &cstat) == 0)

                /*
                 * else we can't write to it but it's not under a version
                 * control system, so just proceed.
                 */
                if (try("%s/RCS/%s%s", filedir, filebase, RCSSUFFIX) ||
                    try("%s/RCS/%s%s", filedir, filebase, "") ||
                    try("%s/%s%s", filedir, filebase, RCSSUFFIX)) {
                        if (!statfailed) {
                                if ((filestat.st_mode & 0222) != 0)
                                        /* The owner can write to it.  */
                                        fatal("file %s seems to be locked "
                                            "by somebody else under RCS\n",
                                            filename);
                                /*
                                 * It might be checked out unlocked.  See if
                                 * it's safe to check out the default version
                                 * locked.
                                 */
                                if (verbose)
                                        say("Comparing file %s to default "
                                            "RCS version...\n", filename);

                                switch (pid = fork()) {
                                case -1:
                                        fatal("can't fork: %s\n",
                                            strerror(errno));
                                case 0:
                                        devnull = open("/dev/null", O_RDONLY);
                                        if (devnull == -1) {
                                                fatal("can't open /dev/null: %s",
                                                    strerror(errno));
                                        }
                                        (void)dup2(devnull, STDOUT_FILENO);
                                        argp[0] = __UNCONST(RCSDIFF);
                                        argp[1] = __UNCONST(filename);
                                        execv(RCSDIFF, argp);
                                        exit(127);
                                }
                                pid = waitpid(pid, &pstat, 0);
                                if (pid == -1 || WEXITSTATUS(pstat) != 0) {
                                        fatal("can't check out file %s: "
                                            "differs from default RCS version\n",
                                            filename);
                                }
                        }

                        if (verbose)
                                say("Checking out file %s from RCS...\n",
                                    filename);

                        switch (pid = fork()) {
                        case -1:
                                fatal("can't fork: %s\n", strerror(errno));
                        case 0:
                                argp[0] = __UNCONST(CHECKOUT);
                                argp[1] = __UNCONST("-l");
                                argp[2] = __UNCONST(filename);
                                execv(CHECKOUT, argp);
                                exit(127);
                        }
                        pid = waitpid(pid, &pstat, 0);
                        if (pid == -1 || WEXITSTATUS(pstat) != 0 ||
                            stat(filename, &filestat)) {
                                fatal("can't check out file %s from RCS\n",
                                    filename);
                        }
                } else if (statfailed) {
                        fatal("can't find %s\n", filename);
                }
                free(lbuf);
                free(tmp_filename1);
                free(tmp_filename2);
        }

        filemode = filestat.st_mode;
        if (!S_ISREG(filemode))
                fatal("%s is not a normal file--can't patch\n", filename);
        i_size = filestat.st_size;
        if (out_of_mem) {
                set_hunkmax();  /* make sure dynamic arrays are allocated */
                out_of_mem = false;
                return false;   /* force plan b because plan a bombed */
        }
        if ((uintmax_t)i_size > (uintmax_t)SIZE_MAX) {
                say("block too large to mmap\n");
                return false;
        }
        if ((ifd = open(filename, O_RDONLY)) < 0)
                pfatal("can't open file %s", filename);

        if (i_size) {
                i_womp = mmap(NULL, i_size, PROT_READ, MAP_PRIVATE, ifd, 0);
                if (i_womp == MAP_FAILED) {
                        perror("mmap failed");
                        i_womp = NULL;
                        close(ifd);
                        return false;
                }
        } else {
                i_womp = NULL;
        }

        close(ifd);
        if (i_size)
                madvise(i_womp, i_size, MADV_SEQUENTIAL);

        /* estimate the number of lines */
        lines_allocated = i_size / 25;
        if (lines_allocated < 100)
                lines_allocated = 100;

        if (!reallocate_lines(&lines_allocated))
                return false;

        /* now scan the buffer and build pointer array */
        iline = 1;
        i_ptr[iline] = i_womp;
        /* test for NUL too, to maintain the behavior of the original code */
        for (s = i_womp, i = 0; i < i_size && *s != '\0'; s++, i++) {
                if (*s == '\n') {
                        if (iline == lines_allocated) {
                                if (!reallocate_lines(&lines_allocated))
                                        return false;
                        }
                        /* these are NOT NUL terminated */
                        i_ptr[++iline] = s + 1;
                }
        }
        /* if the last line contains no EOL, append one */
        if (i_size > 0 && i_womp[i_size - 1] != '\n') {
                last_line_missing_eol = true;
                /* fix last line */
                sz = s - i_ptr[iline];
                p = malloc(sz + 1);
                if (p == NULL) {
                        free(i_ptr);
                        i_ptr = NULL;
                        munmap(i_womp, i_size);
                        i_womp = NULL;
                        return false;
                }

                memcpy(p, i_ptr[iline], sz);
                p[sz] = '\n';
                i_ptr[iline] = p;
                /* count the extra line and make it point to some valid mem */
                i_ptr[++iline] = empty_line;
        } else
                last_line_missing_eol = false;

        input_lines = iline - 1;

        /* now check for revision, if any */

        if (revision != NULL) {
                if (!rev_in_string(i_womp)) {
                        if (force) {
                                if (verbose)
                                        say("Warning: this file doesn't appear "
                                            "to be the %s version--patching anyway.\n",
                                            revision);
                        } else if (batch) {
                                fatal("this file doesn't appear to be the "
                                    "%s version--aborting.\n",
                                    revision);
                        } else {
                                ask("This file doesn't appear to be the "
                                    "%s version--patch anyway? [n] ",
                                    revision);
                                if (*buf != 'y')
                                        fatal("aborted\n");
                        }
                } else if (verbose)
                        say("Good.  This file appears to be the %s version.\n",
                            revision);
        }
        return true;            /* plan a will work */
}

/* Keep (virtually) nothing in memory. */

static void
plan_b(const char *filename)
{
        FILE    *ifp;
        size_t  i = 0, j, maxlen = 1;
        char    *p;
        bool    found_revision = (revision == NULL);

        using_plan_a = false;
        if ((ifp = fopen(filename, "r")) == NULL)
                pfatal("can't open file %s", filename);
        unlink(TMPINNAME);
        if ((tifd = open(TMPINNAME, O_EXCL | O_CREAT | O_WRONLY, 0666)) < 0)
                pfatal("can't open file %s", TMPINNAME);
        while (getline(&buf, &bufsz, ifp) != -1) {
                if (revision != NULL && !found_revision && rev_in_string(buf))
                        found_revision = true;
                if ((i = strlen(buf)) > maxlen)
                        maxlen = i;     /* find longest line */
        }
        last_line_missing_eol = i > 0 && buf[i - 1] != '\n';
        if (last_line_missing_eol && maxlen == i)
                maxlen++;

        if (revision != NULL) {
                if (!found_revision) {
                        if (force) {
                                if (verbose)
                                        say("Warning: this file doesn't appear "
                                            "to be the %s version--patching anyway.\n",
                                            revision);
                        } else if (batch) {
                                fatal("this file doesn't appear to be the "
                                    "%s version--aborting.\n",
                                    revision);
                        } else {
                                ask("This file doesn't appear to be the %s "
                                    "version--patch anyway? [n] ",
                                    revision);
                                if (*buf != 'y')
                                        fatal("aborted\n");
                        }
                } else if (verbose)
                        say("Good.  This file appears to be the %s version.\n",
                            revision);
        }
        fseek(ifp, 0L, SEEK_SET);       /* rewind file */
        lines_per_buf = BUFFERSIZE / maxlen;
        tireclen = maxlen;
        tibuf[0] = malloc(BUFFERSIZE + 1);
        if (tibuf[0] == NULL)
                fatal("out of memory\n");
        tibuf[1] = malloc(BUFFERSIZE + 1);
        if (tibuf[1] == NULL)
                fatal("out of memory\n");
        for (i = 1;; i++) {
                p = tibuf[0] + maxlen * (i % lines_per_buf);
                if (i % lines_per_buf == 0)     /* new block */
                        if (write(tifd, tibuf[0], BUFFERSIZE) < BUFFERSIZE)
                                pfatal("can't write temp file");
                if (fgets(p, maxlen + 1, ifp) == NULL) {
                        input_lines = i - 1;
                        if (i % lines_per_buf != 0)
                                if (write(tifd, tibuf[0], BUFFERSIZE) < BUFFERSIZE)
                                        pfatal("can't write temp file");
                        break;
                }
                j = strlen(p);
                /* These are '\n' terminated strings, so no need to add a NUL */
                if (j == 0 || p[j - 1] != '\n')
                        p[j] = '\n';
        }
        fclose(ifp);
        close(tifd);
        if ((tifd = open(TMPINNAME, O_RDONLY)) < 0)
                pfatal("can't reopen file %s", TMPINNAME);
}

/*
 * Fetch a line from the input file, \n terminated, not necessarily \0.
 */
char *
ifetch(LINENUM line, int whichbuf)
{
        if (line < 1 || line > input_lines) {
                if (warn_on_invalid_line) {
                        say("No such line %ld in input file, ignoring\n", line);
                        warn_on_invalid_line = false;
                }
                return NULL;
        }
        if (using_plan_a)
                return i_ptr[line];
        else {
                LINENUM offline = line % lines_per_buf;
                LINENUM baseline = line - offline;

                if (tiline[0] == baseline)
                        whichbuf = 0;
                else if (tiline[1] == baseline)
                        whichbuf = 1;
                else {
                        tiline[whichbuf] = baseline;

                        if (lseek(tifd, (off_t) (baseline / lines_per_buf *
                            BUFFERSIZE), SEEK_SET) < 0)
                                pfatal("cannot seek in the temporary input file");

                        if (read(tifd, tibuf[whichbuf], BUFFERSIZE) < 0)
                                pfatal("error reading tmp file %s", TMPINNAME);
                }
                return tibuf[whichbuf] + (tireclen * offline);
        }
}

/*
 * True if the string argument contains the revision number we want.
 */
static bool
rev_in_string(const char *string)
{
        const char      *s;
        size_t          patlen;

        if (revision == NULL)
                return true;
        patlen = strlen(revision);
        if (strnEQ(string, revision, patlen) && isspace((unsigned char)string[patlen]))
                return true;
        for (s = string; *s; s++) {
                if (isspace((unsigned char)*s) && strnEQ(s + 1, revision, patlen) &&
                    isspace((unsigned char)s[patlen + 1])) {
                        return true;
                }
        }
        return false;
}