source: MondoRescue/branches/3.3/mindi-busybox/modutils/modutils.c@ 3865

/*
 * Common modutils related functions for busybox
 *
 * Copyright (C) 2008 by Timo Teras <timo.teras@iki.fi>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
#include "modutils.h"

#ifdef __UCLIBC__
extern int init_module(void *module, unsigned long len, const char *options);
extern int delete_module(const char *module, unsigned int flags);
#else
# include <sys/syscall.h>
# define init_module(mod, len, opts) syscall(__NR_init_module, mod, len, opts)
# define delete_module(mod, flags) syscall(__NR_delete_module, mod, flags)
#endif

static module_entry *helper_get_module(module_db *db, const char *module, int create)
{
    char modname[MODULE_NAME_LEN];
    struct module_entry *e;
    unsigned i, hash;

    filename2modname(module, modname);

    hash = 0;
    for (i = 0; modname[i]; i++)
        hash = ((hash << 5) + hash) + modname[i];
    hash %= MODULE_HASH_SIZE;

    for (e = db->buckets[hash]; e; e = e->next)
        if (strcmp(e->modname, modname) == 0)
            return e;
    if (!create)
        return NULL;

    e = xzalloc(sizeof(*e));
    e->modname = xstrdup(modname);
    e->next = db->buckets[hash];
    db->buckets[hash] = e;
    IF_DEPMOD(e->dnext = e->dprev = e;)

    return e;
}
module_entry* FAST_FUNC moddb_get(module_db *db, const char *module)
{
    return helper_get_module(db, module, 0);
}
module_entry* FAST_FUNC moddb_get_or_create(module_db *db, const char *module)
{
    return helper_get_module(db, module, 1);
}

void FAST_FUNC moddb_free(module_db *db)
{
    module_entry *e, *n;
    unsigned i;

    for (i = 0; i < MODULE_HASH_SIZE; i++) {
        for (e = db->buckets[i]; e; e = n) {
            n = e->next;
            free(e->name);
            free(e->modname);
            free(e);
        }
    }
}

void FAST_FUNC replace(char *s, char what, char with)
{
    while (*s) {
        if (what == *s)
            *s = with;
        ++s;
    }
}

char* FAST_FUNC replace_underscores(char *s)
{
    replace(s, '-', '_');
    return s;
}

int FAST_FUNC string_to_llist(char *string, llist_t **llist, const char *delim)
{
    char *tok;
    int len = 0;

    while ((tok = strsep(&string, delim)) != NULL) {
        if (tok[0] == '\0')
            continue;
        llist_add_to_end(llist, xstrdup(tok));
        len += strlen(tok);
    }
    return len;
}

char* FAST_FUNC filename2modname(const char *filename, char *modname)
{
    char local_modname[MODULE_NAME_LEN];
    int i;
    const char *from;

    if (filename == NULL)
        return NULL;
    if (modname == NULL)
        modname = local_modname;
    // Disabled since otherwise "modprobe dir/name" would work
    // as if it is "modprobe name". It is unclear why
    // 'basenamization' was here in the first place.
    //from = bb_get_last_path_component_nostrip(filename);
    from = filename;
    for (i = 0; i < (MODULE_NAME_LEN-1) && from[i] != '\0' && from[i] != '.'; i++)
        modname[i] = (from[i] == '-') ? '_' : from[i];
    modname[i] = '\0';

    if (modname == local_modname)
        return xstrdup(modname);

    return modname;
}

char* FAST_FUNC parse_cmdline_module_options(char **argv, int quote_spaces)
{
    char *options;
    int optlen;

    options = xzalloc(1);
    optlen = 0;
    while (*++argv) {
        const char *fmt;
        const char *var;
        const char *val;

        var = *argv;
        options = xrealloc(options, optlen + 2 + strlen(var) + 2);
        fmt = "%.*s%s ";
        val = strchrnul(var, '=');
        if (quote_spaces) {
            /*
             * modprobe (module-init-tools version 3.11.1) compat:
             * quote only value:
             * var="val with spaces", not "var=val with spaces"
             * (note: var *name* is not checked for spaces!)
             */
            if (*val) { /* has var=val format. skip '=' */
                val++;
                if (strchr(val, ' '))
                    fmt = "%.*s\"%s\" ";
            }
        }
        optlen += sprintf(options + optlen, fmt, (int)(val - var), var, val);
    }
    /* Remove trailing space. Disabled */
    /* if (optlen != 0) options[optlen-1] = '\0'; */
    return options;
}

#if ENABLE_FEATURE_INSMOD_TRY_MMAP
void* FAST_FUNC try_to_mmap_module(const char *filename, size_t *image_size_p)
{
    /* We have user reports of failure to load 3MB module
     * on a 16MB RAM machine. Apparently even a transient
     * memory spike to 6MB during module load
     * is too big for that system. */
    void *image;
    struct stat st;
    int fd;

    fd = xopen(filename, O_RDONLY);
    fstat(fd, &st);
    image = NULL;
    /* st.st_size is off_t, we can't just pass it to mmap */
    if (st.st_size <= *image_size_p) {
        size_t image_size = st.st_size;
        image = mmap(NULL, image_size, PROT_READ, MAP_PRIVATE, fd, 0);
        if (image == MAP_FAILED) {
            image = NULL;
        } else if (*(uint32_t*)image != SWAP_BE32(0x7f454C46)) {
            /* No ELF signature. Compressed module? */
            munmap(image, image_size);
            image = NULL;
        } else {
            /* Success. Report the size */
            *image_size_p = image_size;
        }
    }
    close(fd);
    return image;
}
#endif

/* Return:
 * 0 on success,
 * -errno on open/read error,
 * errno on init_module() error
 */
int FAST_FUNC bb_init_module(const char *filename, const char *options)
{
    size_t image_size;
    char *image;
    int rc;
    bool mmaped;

    if (!options)
        options = "";

//TODO: audit bb_init_module_24 to match error code convention
#if ENABLE_FEATURE_2_4_MODULES
    if (get_linux_version_code() < KERNEL_VERSION(2,6,0))
        return bb_init_module_24(filename, options);
#endif

    image_size = INT_MAX - 4095;
    mmaped = 0;
    image = try_to_mmap_module(filename, &image_size);
    if (image) {
        mmaped = 1;
    } else {
        errno = ENOMEM; /* may be changed by e.g. open errors below */
        image = xmalloc_open_zipped_read_close(filename, &image_size);
        if (!image)
            return -errno;
    }

    errno = 0;
    init_module(image, image_size, options);
    rc = errno;
    if (mmaped)
        munmap(image, image_size);
    else
        free(image);
    return rc;
}

int FAST_FUNC bb_delete_module(const char *module, unsigned int flags)
{
    errno = 0;
    delete_module(module, flags);
    return errno;
}

/* Note: not suitable for delete_module() errnos.
 * For them, probably only EWOULDBLOCK needs explaining:
 * "Other modules depend on us". So far we don't do such
 * translation and don't use moderror() for removal errors.
 */
const char* FAST_FUNC moderror(int err)
{
    switch (err) {
    case -1: /* btw: it's -EPERM */
        return "no such module";
    case ENOEXEC:
        return "invalid module format";
    case ENOENT:
        return "unknown symbol in module, or unknown parameter";
    case ESRCH:
        return "module has wrong symbol version";
    case ENOSYS:
        return "kernel does not support requested operation";
    }
    if (err < 0) /* should always be */
        err = -err;
    return strerror(err);
}