source: mainline/uspace/app/bdsh/util.c@ e2ea8d7e

/* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
 * Copyright (C) 1998 by Wes Peters <wes@softweyr.com>
 * Copyright (c) 1988, 1993 The Regents of the University of California.
 * All rights reserved by all copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 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.
 *
 * Neither the name of the original program's authors nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
 */

/* NOTES:
 * 1 - Various functions were adapted from FreeBSD (copyright holders noted above)
 *     these functions are identified with comments.
 *
 * 2 - Some of these have since appeared in libc. They remain here for various
 *     reasons, such as the eventual integration of garbage collection for things
 *     that allocate memory and don't automatically free it.
 *
 * 3 - Things that expect a pointer to an allocated string do _no_ sanity checking
 *     if developing on a simulator with no debugger, take care :)
 */

#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdarg.h>

#include "config.h"
#include "errors.h"
#include "util.h"

extern volatile int cli_errno;

/* some platforms do not have strdup, implement it here.
 * Returns a pointer to an allocated string or NULL on failure */
char * cli_strdup(const char *s1)
{
        size_t len = strlen(s1) + 1;
        void *ret = malloc(len);

        if (ret == NULL) {
                cli_errno = CL_ENOMEM;
                return (char *) NULL;
        }

        cli_errno = CL_EOK;
        return (char *) memcpy(ret, s1, len);
}

/*
 * Take a previously allocated string (s1), re-size it to accept s2 and copy
 * the contents of s2 into s1.
 * Return -1 on failure, or the length of the copied string on success.
 */
int cli_redup(char **s1, const char *s2)
{
        size_t len = strlen(s2) + 1;

        if (! len)
                return -1;

        *s1 = realloc(*s1, len);

        if (*s1 == NULL) {
                cli_errno = CL_ENOMEM;
                return -1;
        }

        memset(*s1, 0, sizeof(*s1));
        memcpy(*s1, s2, len);
        cli_errno = CL_EOK;
        return (int) len;
}

/* An asprintf() for formatting paths, similar to asprintf() but ensures
 * the returned allocated string is <= PATH_MAX. On failure, an attempt
 * is made to return the original string (if not null) unmodified.
 *
 * Returns: Length of the new string on success, 0 if the string was handed
 * back unmodified, -1 on failure. On failure, cli_errno is set.
 *
 * We do not use POSIX_PATH_MAX, as it is typically much smaller than the
 * PATH_MAX defined by the kernel.
 *
 * Use this like:
 * if (1 > cli_psprintf(&char, "%s/%s", foo, bar)) {
 *   cli_error(cli_errno, "Failed to format path");
 *   stop_what_your_doing_as_your_out_of_memory();
 * }
 */

int cli_psprintf(char **s1, const char *fmt, ...)
{
        va_list ap;
        size_t needed, base = PATH_MAX + 1;
        int skipped = 0;
        char *orig = NULL;
        char *tmp = (char *) malloc(base);

        /* Don't even touch s1, not enough memory */
        if (NULL == tmp) {
                cli_errno = CL_ENOMEM;
                return -1;
        }

        /* If re-allocating s1, save a copy in case we fail */
        if (NULL != *s1)
                orig = cli_strdup(*s1);

        /* Print the string to tmp so we can determine the size that
         * we actually need */
        memset(tmp, 0, sizeof(tmp));
        va_start(ap, fmt);
        /* vsnprintf will return the # of bytes not written */
        skipped = vsnprintf(tmp, base, fmt, ap);
        va_end(ap);

        /* realloc/alloc s1 to be just the size that we need */
        needed = strlen(tmp) + 1;
        *s1 = realloc(*s1, needed);

        if (NULL == *s1) {
                /* No string lived here previously, or we failed to
                 * make a copy of it, either way there's nothing we
                 * can do. */
                if (NULL == *orig) {
                        cli_errno = CL_ENOMEM;
                        return -1;
                }
                /* We can't even allocate enough size to restore the
                 * saved copy, just give up */
                *s1 = realloc(*s1, strlen(orig) + 1);
                if (NULL == *s1) {
                        free(tmp);
                        free(orig);
                        cli_errno = CL_ENOMEM;
                        return -1;
                }
                /* Give the string back as we found it */
                memset(*s1, 0, sizeof(*s1));
                memcpy(*s1, orig, strlen(orig) + 1);
                free(tmp);
                free(orig);
                cli_errno = CL_ENOMEM;
                return 0;
        }

        /* Ok, great, we have enough room */
        memset(*s1, 0, sizeof(*s1));
        memcpy(*s1, tmp, needed);
        free(tmp);

        /* Free tmp only if s1 was reallocated instead of allocated */
        if (NULL != orig)
                free(orig);

        if (skipped) {
                /* s1 was bigger than PATH_MAX when expanded, however part
                 * of the string was printed. Tell the caller not to use it */
                cli_errno = CL_ETOOBIG;
                return -1;
        }

        /* Success! */
        cli_errno = CL_EOK;
        return (int) needed;
}
        
/* Ported from FBSD strtok.c 8.1 (Berkeley) 6/4/93 */
char * cli_strtok_r(char *s, const char *delim, char **last)
{
        char *spanp, *tok;
        int c, sc;

        if (s == NULL && (s = *last) == NULL) {
                cli_errno = CL_EFAIL;
                return (NULL);
        }

cont:
        c = *s++;
        for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
                if (c == sc)
                        goto cont;
        }

        if (c == 0) {           /* no non-delimiter characters */
                *last = NULL;
                return (NULL);
        }

        tok = s - 1;

        for (;;) {
                c = *s++;
                spanp = (char *)delim;
                do {
                        if ((sc = *spanp++) == c) {
                                if (c == 0)
                                        s = NULL;
                                else
                                        s[-1] = '\0';
                                *last = s;
                                return (tok);
                        }
                } while (sc != 0);
        }
}

/* Ported from FBSD strtok.c 8.1 (Berkeley) 6/4/93 */
char * cli_strtok(char *s, const char *delim)
{
        static char *last;

        return (cli_strtok_r(s, delim, &last));
}