mariadb/storage/tokudb/ft-index/portability/toku_path.cc

/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
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  This program is free software; you can redistribute it and/or modify
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  TokuFT, Tokutek Fractal Tree Indexing Library.
  Copyright (C) 2007-2013 Tokutek, Inc.

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  This program is distributed in the hope that it will be useful, but
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UNIVERSITY PATENT NOTICE:

  The technology is licensed by the Massachusetts Institute of
  Technology, Rutgers State University of New Jersey, and the Research
  Foundation of State University of New York at Stony Brook under
  United States of America Serial No. 11/760379 and to the patents
  and/or patent applications resulting from it.

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  This software is covered by US Patent No. 8,185,551.
  This software is covered by US Patent No. 8,489,638.

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*/

#ident "Copyright (c) 2007-2013 Tokutek Inc.  All rights reserved."
#ident "The technology is licensed by the Massachusetts Institute of Technology, Rutgers State University of New Jersey, and the Research Foundation of State University of New York at Stony Brook under United States of America Serial No. 11/760379 and to the patents and/or patent applications resulting from it."

#include "toku_path.h"
#include <toku_assert.h>
#include <stdlib.h>
#include <string.h>
#include <libgen.h>

const char *toku_test_filename(const char *default_filename) {
    const char *filename = getenv("TOKU_TEST_FILENAME");
    if (filename == nullptr) {
        filename = basename((char *) default_filename);
        assert(filename != nullptr);
    }
    return filename;
}

// Guarantees NUL termination (unless siz == 0)
// siz is full size of dst (including NUL terminator)
// Appends src to end of dst, (truncating if necessary) to use no more than siz bytes (including NUL terminator)
// Returns strnlen(dst, siz) (size (excluding NUL) of string we tried to create)
size_t toku_strlcat(char *dst, const char *src, size_t siz)
{
    if (siz == 0) {
        return 0;
    }
    dst[siz-1] = '\0'; //Guarantee NUL termination.

    const size_t old_dst_len = strnlen(dst, siz - 1);
    paranoid_invariant(old_dst_len <= siz - 1);
    if (old_dst_len == siz - 1) {
        // No room for anything more.
        return old_dst_len;
    }
    char *d = &dst[old_dst_len];  //Points to null ptr at end of old string
    const size_t remaining_space = siz-old_dst_len-1;
    const size_t allowed_src_len = strnlen(src, remaining_space);  // Limit to remaining space (leave space for NUL)
    paranoid_invariant(allowed_src_len <= remaining_space);
    paranoid_invariant(old_dst_len + allowed_src_len < siz);
    memcpy(d, src, allowed_src_len);
    d[allowed_src_len] = '\0';  // NUL terminate (may be redundant with previous NUL termination)

    return old_dst_len + allowed_src_len;
}

// Guarantees NUL termination (unless siz == 0)
// siz is full size of dst (including NUL terminator)
// Appends src to end of dst, (truncating if necessary) to use no more than siz bytes (including NUL terminator)
// Returns strnlen(dst, siz) (size (excluding NUL) of string we tried to create)
//
// Implementation note: implemented for simplicity as oppsed to performance
size_t toku_strlcpy(char *dst, const char *src, size_t siz)
{
    if (siz == 0) {
        return 0;
    }
    *dst = '\0';
    return toku_strlcat(dst, src, siz);
}

char *toku_path_join(char *dest, int n, const char *base, ...) {
    static const char PATHSEP = '/';
    size_t written;
    written = toku_strlcpy(dest, base, TOKU_PATH_MAX);
    paranoid_invariant(written < TOKU_PATH_MAX);
    paranoid_invariant(dest[written] == '\0');

    va_list ap;
    va_start(ap, base);
    for (int i = 1; written < TOKU_PATH_MAX && i < n; ++i) {
        if (dest[written - 1] != PATHSEP) {
            if (written+2 >= TOKU_PATH_MAX) {
                // No room.
                break;
            }
            dest[written++] = PATHSEP;
            dest[written] = '\0';
        }
        const char *next = va_arg(ap, const char *);
        written = toku_strlcat(dest, next, TOKU_PATH_MAX);
        paranoid_invariant(written < TOKU_PATH_MAX);
        paranoid_invariant(dest[written] == '\0');
    }
    va_end(ap);

    // Zero out rest of buffer for security
    memset(&dest[written], 0, TOKU_PATH_MAX - written);
    return dest;
}