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/*

 * 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;

}

        cli_error(cli_errno, "Failed to set prompt");

        return 1;

    }