Patrick Welche <prlw1@cam.ac.uk>

[netbsd-mini2440.git] / external / bsd / libarchive / dist / tar / util.c

/*-
 * Copyright (c) 2003-2007 Tim Kientzle
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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(S) 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.
 */

#include "bsdtar_platform.h"
__FBSDID("$FreeBSD: src/usr.bin/tar/util.c,v 1.20 2008/06/09 14:03:55 cperciva Exp $");

#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>  /* Linux doesn't define mode_t, etc. in sys/stat.h. */
#endif
#include <ctype.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STDARG_H
#include <stdarg.h>
#endif
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

#include "bsdtar.h"

static void     bsdtar_vwarnc(struct bsdtar *, int code,
                    const char *fmt, va_list ap);

/*
 * Print a string, taking care with any non-printable characters.
 */

void
safe_fprintf(FILE *f, const char *fmt, ...)
{
        char *buff;
        char *buff_heap;
        int buff_length;
        int length;
        va_list ap;
        char *p;
        unsigned i;
        char buff_stack[256];
        char copy_buff[256];

        /* Use a stack-allocated buffer if we can, for speed and safety. */
        buff_heap = NULL;
        buff_length = sizeof(buff_stack);
        buff = buff_stack;

        va_start(ap, fmt);
        length = vsnprintf(buff, buff_length, fmt, ap);
        va_end(ap);
        /* If the result is too large, allocate a buffer on the heap. */
        if (length >= buff_length) {
                buff_length = length+1;
                buff_heap = malloc(buff_length);
                /* Failsafe: use the truncated string if malloc fails. */
                if (buff_heap != NULL) {
                        buff = buff_heap;
                        va_start(ap, fmt);
                        length = vsnprintf(buff, buff_length, fmt, ap);
                        va_end(ap);
                }
        }

        /* Write data, expanding unprintable characters. */
        p = buff;
        i = 0;
        while (*p != '\0') {
                unsigned char c = *p++;

                if (isprint(c) && c != '\\')
                        copy_buff[i++] = c;
                else {
                        copy_buff[i++] = '\\';
                        switch (c) {
                        case '\a': copy_buff[i++] = 'a'; break;
                        case '\b': copy_buff[i++] = 'b'; break;
                        case '\f': copy_buff[i++] = 'f'; break;
                        case '\n': copy_buff[i++] = 'n'; break;
#if '\r' != '\n'
                        /* On some platforms, \n and \r are the same. */
                        case '\r': copy_buff[i++] = 'r'; break;
#endif
                        case '\t': copy_buff[i++] = 't'; break;
                        case '\v': copy_buff[i++] = 'v'; break;
                        case '\\': copy_buff[i++] = '\\'; break;
                        default:
                                sprintf(copy_buff + i, "%03o", c);
                                i += 3;
                        }
                }

                /* If our temp buffer is full, dump it and keep going. */
                if (i > (sizeof(copy_buff) - 8)) {
                        copy_buff[i++] = '\0';
                        fprintf(f, "%s", copy_buff);
                        i = 0;
                }
        }
        copy_buff[i++] = '\0';
        fprintf(f, "%s", copy_buff);

        /* If we allocated a heap-based buffer, free it now. */
        if (buff_heap != NULL)
                free(buff_heap);
}

static void
bsdtar_vwarnc(struct bsdtar *bsdtar, int code, const char *fmt, va_list ap)
{
        fprintf(stderr, "%s: ", bsdtar->progname);
        vfprintf(stderr, fmt, ap);
        if (code != 0)
                fprintf(stderr, ": %s", strerror(code));
        fprintf(stderr, "\n");
}

void
bsdtar_warnc(struct bsdtar *bsdtar, int code, const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        bsdtar_vwarnc(bsdtar, code, fmt, ap);
        va_end(ap);
}

void
bsdtar_errc(struct bsdtar *bsdtar, int eval, int code, const char *fmt, ...)
{
        va_list ap;

        va_start(ap, fmt);
        bsdtar_vwarnc(bsdtar, code, fmt, ap);
        va_end(ap);
        exit(eval);
}

int
yes(const char *fmt, ...)
{
        char buff[32];
        char *p;
        ssize_t l;

        va_list ap;
        va_start(ap, fmt);
        vfprintf(stderr, fmt, ap);
        va_end(ap);
        fprintf(stderr, " (y/N)? ");
        fflush(stderr);

        l = read(2, buff, sizeof(buff) - 1);
        if (l <= 0)
                return (0);
        buff[l] = 0;

        for (p = buff; *p != '\0'; p++) {
                if (isspace(0xff & (int)*p))
                        continue;
                switch(*p) {
                case 'y': case 'Y':
                        return (1);
                case 'n': case 'N':
                        return (0);
                default:
                        return (0);
                }
        }

        return (0);
}

/*
 * Read lines from file and do something with each one.  If option_null
 * is set, lines are terminated with zero bytes; otherwise, they're
 * terminated with newlines.
 *
 * This uses a self-sizing buffer to handle arbitrarily-long lines.
 * If the "process" function returns non-zero for any line, this
 * function will return non-zero after attempting to process all
 * remaining lines.
 */
int
process_lines(struct bsdtar *bsdtar, const char *pathname,
    int (*process)(struct bsdtar *, const char *))
{
        FILE *f;
        char *buff, *buff_end, *line_start, *line_end, *p;
        size_t buff_length, new_buff_length, bytes_read, bytes_wanted;
        int separator;
        int ret;

        separator = bsdtar->option_null ? '\0' : '\n';
        ret = 0;

        if (strcmp(pathname, "-") == 0)
                f = stdin;
        else
                f = fopen(pathname, "r");
        if (f == NULL)
                bsdtar_errc(bsdtar, 1, errno, "Couldn't open %s", pathname);
        buff_length = 8192;
        buff = malloc(buff_length);
        if (buff == NULL)
                bsdtar_errc(bsdtar, 1, ENOMEM, "Can't read %s", pathname);
        line_start = line_end = buff_end = buff;
        for (;;) {
                /* Get some more data into the buffer. */
                bytes_wanted = buff + buff_length - buff_end;
                bytes_read = fread(buff_end, 1, bytes_wanted, f);
                buff_end += bytes_read;
                /* Process all complete lines in the buffer. */
                while (line_end < buff_end) {
                        if (*line_end == separator) {
                                *line_end = '\0';
                                if ((*process)(bsdtar, line_start) != 0)
                                        ret = -1;
                                line_start = line_end + 1;
                                line_end = line_start;
                        } else
                                line_end++;
                }
                if (feof(f))
                        break;
                if (ferror(f))
                        bsdtar_errc(bsdtar, 1, errno,
                            "Can't read %s", pathname);
                if (line_start > buff) {
                        /* Move a leftover fractional line to the beginning. */
                        memmove(buff, line_start, buff_end - line_start);
                        buff_end -= line_start - buff;
                        line_end -= line_start - buff;
                        line_start = buff;
                } else {
                        /* Line is too big; enlarge the buffer. */
                        new_buff_length = buff_length * 2;
                        if (new_buff_length <= buff_length)
                                bsdtar_errc(bsdtar, 1, ENOMEM,
                                    "Line too long in %s", pathname);
                        buff_length = new_buff_length;
                        p = realloc(buff, buff_length);
                        if (p == NULL)
                                bsdtar_errc(bsdtar, 1, ENOMEM,
                                    "Line too long in %s", pathname);
                        buff_end = p + (buff_end - buff);
                        line_end = p + (line_end - buff);
                        line_start = buff = p;
                }
        }
        /* At end-of-file, handle the final line. */
        if (line_end > line_start) {
                *line_end = '\0';
                if ((*process)(bsdtar, line_start) != 0)
                        ret = -1;
        }
        free(buff);
        if (f != stdin)
                fclose(f);
        return (ret);
}

/*-
 * The logic here for -C <dir> attempts to avoid
 * chdir() as long as possible.  For example:
 * "-C /foo -C /bar file"          needs chdir("/bar") but not chdir("/foo")
 * "-C /foo -C bar file"           needs chdir("/foo/bar")
 * "-C /foo -C bar /file1"         does not need chdir()
 * "-C /foo -C bar /file1 file2"   needs chdir("/foo/bar") before file2
 *
 * The only correct way to handle this is to record a "pending" chdir
 * request and combine multiple requests intelligently until we
 * need to process a non-absolute file.  set_chdir() adds the new dir
 * to the pending list; do_chdir() actually executes any pending chdir.
 *
 * This way, programs that build tar command lines don't have to worry
 * about -C with non-existent directories; such requests will only
 * fail if the directory must be accessed.
 */
void
set_chdir(struct bsdtar *bsdtar, const char *newdir)
{
        if (newdir[0] == '/') {
                /* The -C /foo -C /bar case; dump first one. */
                free(bsdtar->pending_chdir);
                bsdtar->pending_chdir = NULL;
        }
        if (bsdtar->pending_chdir == NULL)
                /* Easy case: no previously-saved dir. */
                bsdtar->pending_chdir = strdup(newdir);
        else {
                /* The -C /foo -C bar case; concatenate */
                char *old_pending = bsdtar->pending_chdir;
                size_t old_len = strlen(old_pending);
                bsdtar->pending_chdir = malloc(old_len + strlen(newdir) + 2);
                if (old_pending[old_len - 1] == '/')
                        old_pending[old_len - 1] = '\0';
                if (bsdtar->pending_chdir != NULL)
                        sprintf(bsdtar->pending_chdir, "%s/%s",
                            old_pending, newdir);
                free(old_pending);
        }
        if (bsdtar->pending_chdir == NULL)
                bsdtar_errc(bsdtar, 1, errno, "No memory");
}

void
do_chdir(struct bsdtar *bsdtar)
{
        if (bsdtar->pending_chdir == NULL)
                return;

        if (chdir(bsdtar->pending_chdir) != 0) {
                bsdtar_errc(bsdtar, 1, 0, "could not chdir to '%s'\n",
                    bsdtar->pending_chdir);
        }
        free(bsdtar->pending_chdir);
        bsdtar->pending_chdir = NULL;
}

/*
 * Handle --strip-components and any future path-rewriting options.
 * Returns non-zero if the pathname should not be extracted.
 *
 * TODO: Support pax-style regex path rewrites.
 */
int
edit_pathname(struct bsdtar *bsdtar, struct archive_entry *entry)
{
        const char *name = archive_entry_pathname(entry);
#if HAVE_REGEX_H
        char *subst_name;
#endif
        int r;

#if HAVE_REGEX_H
        r = apply_substitution(bsdtar, name, &subst_name, 0);
        if (r == -1) {
                bsdtar_warnc(bsdtar, 0, "Invalid substituion, skipping entry");
                return 1;
        }
        if (r == 1) {
                archive_entry_copy_pathname(entry, subst_name);
                if (*subst_name == '\0') {
                        free(subst_name);
                        return -1;
                } else
                        free(subst_name);
                name = archive_entry_pathname(entry);
        }

        if (archive_entry_hardlink(entry)) {
                r = apply_substitution(bsdtar, archive_entry_hardlink(entry), &subst_name, 1);
                if (r == -1) {
                        bsdtar_warnc(bsdtar, 0, "Invalid substituion, skipping entry");
                        return 1;
                }
                if (r == 1) {
                        archive_entry_copy_hardlink(entry, subst_name);
                        free(subst_name);
                }
        }
        if (archive_entry_symlink(entry) != NULL) {
                r = apply_substitution(bsdtar, archive_entry_symlink(entry), &subst_name, 1);
                if (r == -1) {
                        bsdtar_warnc(bsdtar, 0, "Invalid substituion, skipping entry");
                        return 1;
                }
                if (r == 1) {
                        archive_entry_copy_symlink(entry, subst_name);
                        free(subst_name);
                }
        }
#endif

        /* Strip leading dir names as per --strip-components option. */
        if ((r = bsdtar->strip_components) > 0) {
                const char *p = name;

                while (r > 0) {
                        switch (*p++) {
                        case '/':
                                r--;
                                name = p;
                                break;
                        case '\0':
                                /* Path is too short, skip it. */
                                return (1);
                        }
                }
                while (*name == '/')
                        ++name;
                if (*name == '\0')
                        return (1);
        }

        /* Strip redundant leading '/' characters. */
        while (name[0] == '/' && name[1] == '/')
                name++;

        /* Strip leading '/' unless user has asked us not to. */
        if (name[0] == '/' && !bsdtar->option_absolute_paths) {
                /* Generate a warning the first time this happens. */
                if (!bsdtar->warned_lead_slash) {
                        bsdtar_warnc(bsdtar, 0,
                            "Removing leading '/' from member names");
                        bsdtar->warned_lead_slash = 1;
                }
                name++;
                /* Special case: Stripping leading '/' from "/" yields ".". */
                if (*name == '\0')
                        name = ".";
        }

        /* Safely replace name in archive_entry. */
        if (name != archive_entry_pathname(entry)) {
                char *q = strdup(name);
                archive_entry_copy_pathname(entry, q);
                free(q);
        }
        return (0);
}

/*
 * Like strcmp(), but try to be a little more aware of the fact that
 * we're comparing two paths.  Right now, it just handles leading
 * "./" and trailing '/' specially, so that "a/b/" == "./a/b"
 *
 * TODO: Make this better, so that "./a//b/./c/" == "a/b/c"
 * TODO: After this works, push it down into libarchive.
 * TODO: Publish the path normalization routines in libarchive so
 * that bsdtar can normalize paths and use fast strcmp() instead
 * of this.
 */

int
pathcmp(const char *a, const char *b)
{
        /* Skip leading './' */
        if (a[0] == '.' && a[1] == '/' && a[2] != '\0')
                a += 2;
        if (b[0] == '.' && b[1] == '/' && b[2] != '\0')
                b += 2;
        /* Find the first difference, or return (0) if none. */
        while (*a == *b) {
                if (*a == '\0')
                        return (0);
                a++;
                b++;
        }
        /*
         * If one ends in '/' and the other one doesn't,
         * they're the same.
         */
        if (a[0] == '/' && a[1] == '\0' && b[0] == '\0')
                return (0);
        if (a[0] == '\0' && b[0] == '/' && b[1] == '\0')
                return (0);
        /* They're really different, return the correct sign. */
        return (*(const unsigned char *)a - *(const unsigned char *)b);
}