Merge ../remotes/kay-mit

[mit.git] / depmod.c

/* New simplified depmod without backwards compat stuff and not
   requiring ksyms.

   (C) 2002 Rusty Russell IBM Corporation
 */
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <elf.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <sys/utsname.h>
#include <sys/mman.h>

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

#include "zlibsupport.h"
#include "depmod.h"
#include "moduleops.h"
#include "tables.h"

#include "testing.h"

#ifndef MODULE_DIR
#define MODULE_DIR "/lib/modules/"
#endif

#ifndef MODULE_BUILTIN_KEY
#define MODULE_BUILTIN_KEY "built-in"
#endif

struct module_overrides
{
        /* Next override */
        struct module_overrides *next;

        /* overridden module */
        char *modfile;
};

struct module_search
{
        /* Next search */
        struct module_search *next;

        /* search path */
        char *search_path;
};

static int verbose;
static unsigned int skipchars;

void fatal(const char *fmt, ...)
{
        va_list arglist;

        fprintf(stderr, "FATAL: ");

        va_start(arglist, fmt);
        vfprintf(stderr, fmt, arglist);
        va_end(arglist);

        exit(1);
}

void warn(const char *fmt, ...)
{
        va_list arglist;

        fprintf(stderr, "WARNING: ");

        va_start(arglist, fmt);
        vfprintf(stderr, fmt, arglist);
        va_end(arglist);
}

void *do_nofail(void *ptr, const char *file, int line, const char *expr)
{
        if (!ptr) {
                fatal("Memory allocation failure %s line %d: %s.\n",
                      file, line, expr);
        }
        return ptr;
}

#define SYMBOL_HASH_SIZE 1024
struct symbol
{
        struct symbol *next;
        struct module *owner;
        char name[0];
};

static struct symbol *symbolhash[SYMBOL_HASH_SIZE];

/* This is based on the hash agorithm from gdbm, via tdb */
static inline unsigned int tdb_hash(const char *name)
{
        unsigned value; /* Used to compute the hash value.  */
        unsigned   i;   /* Used to cycle through random values. */

        /* Set the initial value from the key size. */
        for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
                value = (value + (((unsigned char *)name)[i] << (i*5 % 24)));

        return (1103515243 * value + 12345);
}

void add_symbol(const char *name, struct module *owner)
{
        unsigned int hash;
        struct symbol *new = NOFAIL(malloc(sizeof *new + strlen(name) + 1));

        new->owner = owner;
        strcpy(new->name, name);

        hash = tdb_hash(name) % SYMBOL_HASH_SIZE;
        new->next = symbolhash[hash];
        symbolhash[hash] = new;
}

static int print_unknown;

struct module *find_symbol(const char *name, const char *modname, int weak)
{
        struct symbol *s;

        /* For our purposes, .foo matches foo.  PPC64 needs this. */
        if (name[0] == '.')
                name++;

        for (s = symbolhash[tdb_hash(name) % SYMBOL_HASH_SIZE]; s; s=s->next) {
                if (streq(s->name, name))
                        return s->owner;
        }

        if (print_unknown && !weak)
                warn("%s needs unknown symbol %s\n", modname, name);

        return NULL;
}

void add_dep(struct module *mod, struct module *depends_on)
{
        unsigned int i;

        for (i = 0; i < mod->num_deps; i++)
                if (mod->deps[i] == depends_on)
                        return;

        mod->deps = NOFAIL(realloc(mod->deps, sizeof(mod->deps[0])*(mod->num_deps+1)));
        mod->deps[mod->num_deps++] = depends_on;
}

static void load_system_map(const char *filename)
{
        FILE *system_map;
        char line[10240];
        const char ksymstr[] = "__ksymtab_";
        const int ksymstr_len = strlen(ksymstr);

        system_map = fopen(filename, "r");
        if (!system_map)
                fatal("Could not open '%s': %s\n", filename, strerror(errno));

        /* eg. c0294200 R __ksymtab_devfs_alloc_devnum */
        while (fgets(line, sizeof(line)-1, system_map)) {
                char *ptr;

                /* Snip \n */
                ptr = strchr(line, '\n');
                if (ptr)
                        *ptr = '\0';

                ptr = strchr(line, ' ');
                if (!ptr || !(ptr = strchr(ptr + 1, ' ')))
                        continue;

                /* Covers gpl-only and normal symbols. */
                if (strncmp(ptr+1, ksymstr, ksymstr_len) == 0)
                        add_symbol(ptr+1+ksymstr_len, NULL);
        }

        fclose(system_map);

        /* __this_module is magic inserted by kernel loader. */
        add_symbol("__this_module", NULL);
        /* On S390, this is faked up too */
        add_symbol("_GLOBAL_OFFSET_TABLE_", NULL);
}

static struct option options[] = { { "all", 0, NULL, 'a' },
                                   { "quick", 0, NULL, 'A' },
                                   { "basedir", 1, NULL, 'b' },
                                   { "errsyms", 0, NULL, 'e' },
                                   { "filesyms", 1, NULL, 'F' },
                                   { "help", 0, NULL, 'h' },
                                   { "show", 0, NULL, 'n' },
                                   { "dry-run", 0, NULL, 'n' },
                                   { "quiet", 0, NULL, 'q' },
                                   { "root", 0, NULL, 'r' },
                                   { "unresolved-error", 0, NULL, 'u' },
                                   { "verbose", 0, NULL, 'v' },
                                   { "version", 0, NULL, 'V' },
                                   { "config", 1, NULL, 'C' },
                                   { NULL, 0, NULL, 0 } };

/* Version number or module name?  Don't assume extension. */
static int is_version_number(const char *version)
{
        unsigned int dummy;

        return (sscanf(version, "%u.%u.%u", &dummy, &dummy, &dummy) == 3);
}

static int old_module_version(const char *version)
{
        /* Expect three part version. */
        unsigned int major, sub, minor;

        sscanf(version, "%u.%u.%u", &major, &sub, &minor);

        if (major > 2) return 0;
        if (major < 2) return 1;

        /* 2.x */
        if (sub > 5) return 0;
        if (sub < 5) return 1;

        /* 2.5.x */
        if (minor >= 48) return 0;
        return 1;
}

static void exec_old_depmod(char *argv[])
{
        char *sep;
        char pathname[strlen(argv[0])+1];
        char oldname[strlen("depmod") + strlen(argv[0]) + sizeof(".old")];

        memset(pathname, 0, strlen(argv[0])+1);
        sep = strrchr(argv[0], '/');
        if (sep)
                memcpy(pathname, argv[0], sep - argv[0]+1);
        sprintf(oldname, "%s%s.old", pathname, "depmod");

        /* Recursion detection: we need an env var since we can't
           change argv[0] (as older modutils uses it to determine
           behavior). */
        if (getenv("MODULE_RECURSE"))
                return;
        setenv("MODULE_RECURSE", "y", 0);

        execvp(oldname, argv);
        fprintf(stderr,
                "Version requires old depmod, but couldn't run %s: %s\n",
                oldname, strerror(errno));
        exit(2);
}

static void grammar(const char *cmd, const char *filename, unsigned int line)
{
        warn("%s line %u: ignoring bad line starting with '%s'\n",
                                                filename, line, cmd);
}


static void print_usage(const char *name)
{
        fprintf(stderr,
        "%s " VERSION " -- part of " PACKAGE "\n"
        "%s -[aA] [-n -e -v -q -V -r -u]\n"
        "      [-b basedirectory] [forced_version]\n"
        "depmod [-n -e -v -q -r -u] [-F kernelsyms] module1.ko module2.ko ...\n"
        "If no arguments (except options) are given, \"depmod -a\" is assumed\n"
        "\n"
        "depmod will output a dependancy list suitable for the modprobe utility.\n"
        "\n"
        "\n"
        "Options:\n"
        "\t-a, --all            Probe all modules\n"
        "\t-A, --quick          Only does the work if there's a new module\n"
        "\t-n, --show           Write the dependency file on stdout only\n"
        "\t-e, --errsyms        Report not supplied symbols\n"
        "\t-V, --version        Print the release version\n"
        "\t-v, --verbose        Enable verbose mode\n"
        "\t-h, --help           Print this usage message\n"
        "\n"
        "The following options are useful for people managing distributions:\n"
        "\t-b basedirectory\n"
        "\t    --basedir basedirectory    Use an image of a module tree.\n"
        "\t-F kernelsyms\n"
        "\t    --filesyms kernelsyms      Use the file instead of the\n"
        "\t                               current kernel symbols.\n",
        "depmod", "depmod");
}

static int ends_in(const char *name, const char *ext)
{
        unsigned int namelen, extlen;

        /* Grab lengths */
        namelen = strlen(name);
        extlen = strlen(ext);

        if (namelen < extlen) return 0;

        if (streq(name + namelen - extlen, ext))
                return 1;
        return 0;
}

/* "\177ELF" <byte> where byte = 001 for 32-bit, 002 for 64 */
int needconv(const char *elfhdr)
{
        union { short s; char c[2]; } endian_test;

        endian_test.s = 1;
        if (endian_test.c[1] == 1) return elfhdr[EI_DATA] != ELFDATA2MSB;
        if (endian_test.c[0] == 1) return elfhdr[EI_DATA] != ELFDATA2LSB;
        else
                abort();
}

static struct module *grab_module(const char *dirname, const char *filename)
{
        struct module *new;

        new = NOFAIL(malloc(sizeof(*new)
                            + strlen(dirname?:"") + 1 + strlen(filename) + 1));
        if (dirname)
                sprintf(new->pathname, "%s/%s", dirname, filename);
        else
                strcpy(new->pathname, filename);

        INIT_LIST_HEAD(&new->dep_list);

        new->data = grab_file(new->pathname, &new->len);
        if (!new->data) {
                warn("Can't read module %s: %s\n",
                     new->pathname, strerror(errno));
                goto fail_data;
        }

        /* "\177ELF" <byte> where byte = 001 for 32-bit, 002 for 64 */
        if (memcmp(new->data, ELFMAG, SELFMAG) != 0) {
                warn("Module %s is not an elf object\n", new->pathname);
                goto fail;
        }

        switch (((char *)new->data)[EI_CLASS]) {
        case ELFCLASS32:
                new->ops = &mod_ops32;
                break;
        case ELFCLASS64:
                new->ops = &mod_ops64;
                break;
        default:
                warn("Module %s has elf unknown identifier %i\n",
                     new->pathname, ((char *)new->data)[EI_CLASS]);
                goto fail;
        }
        new->conv = needconv(new->data);
        return new;

fail:
        release_file(new->data, new->len);
fail_data:
        free(new);
        return NULL;
}

struct module_traverse
{
        struct module_traverse *prev;
        struct module *mod;
};

static int in_loop(struct module *mod, const struct module_traverse *traverse)
{
        const struct module_traverse *i;

        for (i = traverse; i; i = i->prev) {
                if (i->mod == mod)
                        return 1;
        }
        return 0;
}

static char *basename(const char *name)
{
        const char *base = strrchr(name, '/');
        if (base) return (char *)base + 1;
        return (char *)name;
}

/* Assume we are doing all the modules, so only report each loop once. */
static void report_loop(const struct module *mod,
                        const struct module_traverse *traverse)
{
        const struct module_traverse *i;

        /* Check that start is least alphabetically.  eg.  a depends
           on b depends on a will get reported for a, not b.  */
        for (i = traverse->prev; i->prev; i = i->prev) {
                if (strcmp(mod->pathname, i->mod->pathname) > 0)
                        return;
        }

        /* Is start in the loop?  If not, don't report now. eg. a
           depends on b which depends on c which depends on b.  Don't
           report when generating depends for a. */
        if (mod != i->mod)
                return;

        warn("Loop detected: %s ", mod->pathname);
        for (i = traverse->prev; i->prev; i = i->prev)
                fprintf(stderr, "needs %s ", basename(i->mod->pathname));
        fprintf(stderr, "which needs %s again!\n", basename(mod->pathname));
}

/* This is damn slow, but loops actually happen, and we don't want to
   just exit() and leave the user without any modules. */
static int has_dep_loop(struct module *module, struct module_traverse *prev)
{
        unsigned int i;
        struct module_traverse traverse = { .prev = prev, .mod = module };

        if (in_loop(module, prev)) {
                report_loop(module, &traverse);
                return 1;
        }

        for (i = 0; i < module->num_deps; i++)
                if (has_dep_loop(module->deps[i], &traverse))
                        return 1;
        return 0;
}

/* Uniquifies and orders a dependency list. */
static void order_dep_list(struct module *start, struct module *mod)
{
        unsigned int i;

        for (i = 0; i < mod->num_deps; i++) {
                /* If it was previously depended on, move it to the
                   tail.  ie. if a needs b and c, and c needs b, we
                   must order b after c. */
                list_del(&mod->deps[i]->dep_list);
                list_add_tail(&mod->deps[i]->dep_list, &start->dep_list);
                order_dep_list(start, mod->deps[i]);
        }
}

static void del_module(struct module **modules, struct module *delme)
{
        struct module **i;

        /* Find pointer to it. */ 
        for (i = modules; *i != delme; i = &(*i)->next);

        *i = delme->next;
}

static void output_deps(struct module *modules,
                        FILE *out)
{
        struct module *i;

        for (i = modules; i; i = i->next)
                i->ops->calculate_deps(i, verbose);

        /* Strip out loops. */
 again:
        for (i = modules; i; i = i->next) {
                if (has_dep_loop(i, NULL)) {
                        warn("Module %s ignored, due to loop\n",
                             i->pathname + skipchars);
                        del_module(&modules, i);
                        goto again;
                }
        }

        /* Now dump them out. */
        for (i = modules; i; i = i->next) {
                struct list_head *j, *tmp;
                order_dep_list(i, i);

                fprintf(out, "%s:", i->pathname + skipchars);
                list_for_each_safe(j, tmp, &i->dep_list) {
                        struct module *dep
                                = list_entry(j, struct module, dep_list);
                        fprintf(out, " %s", dep->pathname + skipchars);
                        list_del_init(j);
                }
                fprintf(out, "\n");
        }
}

static int smells_like_module(const char *name)
{
        return ends_in(name,".ko") || ends_in(name, ".ko.gz");
}

typedef struct module *(*do_module_t)(const char *dirname,
                                      const char *filename,
                                      struct module *next,
                                      struct module_search *search,
                                      struct module_overrides *overrides);

static int is_higher_priority(const char *newpath, const char *oldpath,
                              struct module_search *search,
                              struct module_overrides *overrides)
{
        char *p, *q, *s;
        struct module_search *tmp;
        struct module_overrides *ovtmp;
        int i = 0;
        int prio_builtin = -1;
        int prio_new = -1;
        int prio_old = -1;

/* The names already match, now we check for wildcard overrides and other
 * high priority overrides we added to the config.
 */
        for (ovtmp=overrides;ovtmp!=NULL;ovtmp=ovtmp->next) {

                p = strstr(ovtmp->modfile,newpath);
                if (p)
                        return 1;

                q = strstr(ovtmp->modfile,"*");
                if (q) {
                        p = strstr(newpath, q+1);
                        if (p)
                                return 1;

                        p = strstr(oldpath, q+1);
                        if (p)
                                return 0;
                }

                p = strstr(ovtmp->modfile,oldpath);
                if (p)
                        return 0;
        }
        
        for (i=0,tmp=search;tmp!=NULL;tmp=tmp->next,i++) {

                s = NOFAIL(malloc(strlen(tmp->search_path)+2));
                s[0] = '/';
                strncpy(s+1,tmp->search_path, strlen(tmp->search_path)+1);

                if (0 == strncmp(tmp->search_path,MODULE_BUILTIN_KEY,
                                 strlen(MODULE_BUILTIN_KEY)))
                        prio_builtin = i;
                        
                p = strstr(newpath,s);
                if ((p) && ((p[strlen(s)] == '/')
                        ||  (p[strlen(s)] == '\0')))
                        prio_new = i;

                p = strstr(oldpath,s);
                if ((p) && ((p[strlen(s)] == '/')
                        ||  (p[strlen(s)] == '\0')))
                        prio_old = i;
        
                free(s);
                
        }

        if (prio_new < 0)
                prio_new = prio_builtin;
        
        if (prio_old < 0)
                prio_old = prio_builtin;

        return prio_new > prio_old;
        
}


static struct module *do_module(const char *dirname,
                                       const char *filename,
                                       struct module *list,
                                       struct module_search *search,
                                       struct module_overrides *overrides)
{
        struct module *new, **i;

        new = grab_module(dirname, filename);
        if (!new)
                return list;

        /* Check if module is already in the list. */
        for (i = &list; *i; i = &(*i)->next) {

                if (streq(basename((*i)->pathname), filename)) {
                        char newpath[strlen(dirname) + strlen("/")
                                      + strlen(filename) + 1];

                        sprintf(newpath, "%s/%s", dirname, filename);

                        if (is_higher_priority(newpath, (*i)->pathname,search,
                                               overrides)) {
                                new->next = (*i)->next;

                                release_file((*i)->data, (*i)->len);
                                free(*i);

                                *i = new;
                        } else
                                free(new);

                        return list;
                }
        }

        /* Not in the list already. Just prepend. */
        new->next = list;
        return new;
}

static struct module *grab_dir(const char *dirname,
                               DIR *dir,
                               struct module *next,
                               do_module_t do_mod,
                               struct module_search *search,
                               struct module_overrides *overrides)
{
        struct dirent *dirent;

        while ((dirent = readdir(dir)) != NULL) {
                if (smells_like_module(dirent->d_name))
                        next = do_mod(dirname, dirent->d_name, next,
                                      search, overrides);
                else if (!streq(dirent->d_name, ".")
                         && !streq(dirent->d_name, "..")
                         && !streq(dirent->d_name, "source")
                         && !streq(dirent->d_name, "build")) {

                        DIR *sub;
                        char subdir[strlen(dirname) + 1
                                   + strlen(dirent->d_name) + 1];
                        sprintf(subdir, "%s/%s", dirname, dirent->d_name);
                        sub = opendir(subdir);
                        if (sub) {
                                next = grab_dir(subdir, sub, next, do_mod,
                                                search, overrides);
                                closedir(sub);
                        }
                }
        }
        return next;
}

static struct module *grab_basedir(const char *dirname,
                                   struct module_search *search,
                                   struct module_overrides *overrides)
{
        DIR *dir;
        struct module *list;

        dir = opendir(dirname);
        if (!dir) {
                warn("Couldn't open directory %s: %s\n",
                     dirname, strerror(errno));
                return NULL;
        }
        list = grab_dir(dirname, dir, NULL, do_module, search, overrides);
        closedir(dir);

        return list;
}

static void parse_modules(struct module *list)
{
        struct module *i;

        for (i = list; i; i = i->next) {
                i->ops->load_symbols(i);
                i->ops->fetch_tables(i);
        }
}

/* Convert filename to the module name.  Works if filename == modname, too. */
static void filename2modname(char *modname, const char *filename)
{
        const char *afterslash;
        unsigned int i;

        afterslash = strrchr(filename, '/');
        if (!afterslash)
                afterslash = filename;
        else
                afterslash++;

        /* Convert to underscores, stop at first . */
        for (i = 0; afterslash[i] && afterslash[i] != '.'; i++) {
                if (afterslash[i] == '-')
                        modname[i] = '_';
                else
                        modname[i] = afterslash[i];
        }
        modname[i] = '\0';
}

/* Simply dump hash table. */
static void output_symbols(struct module *unused, FILE *out)
{
        unsigned int i;

        fprintf(out, "# Aliases for symbols, used by symbol_request().\n");
        for (i = 0; i < SYMBOL_HASH_SIZE; i++) {
                struct symbol *s;

                for (s = symbolhash[i]; s; s = s->next) {
                        if (s->owner) {
                                char modname[strlen(s->owner->pathname)+1];
                                filename2modname(modname, s->owner->pathname);
                                fprintf(out, "alias symbol:%s %s\n",
                                        s->name, modname);
                        }
                }
        }
}

static const char *next_string(const char *string, unsigned long *secsize)
{
        /* Skip non-zero chars */
        while (string[0]) {
                string++;
                if ((*secsize)-- <= 1)
                        return NULL;
        }

        /* Skip any zero padding. */
        while (!string[0]) {
                string++;
                if ((*secsize)-- <= 1)
                        return NULL;
        }
        return string;
}

static void output_aliases(struct module *modules, FILE *out)
{
        struct module *i;
        const char *p;
        unsigned long size;

        fprintf(out, "# Aliases extracted from modules themselves.\n");
        for (i = modules; i; i = i->next) {
                char modname[strlen(i->pathname)+1];

                filename2modname(modname, i->pathname);

                /* Grab from old-style .modalias section. */
                for (p = i->ops->get_aliases(i, &size);
                     p;
                     p = next_string(p, &size))
                        fprintf(out, "alias %s %s\n", p, modname);

                /* Grab form new-style .modinfo section. */
                for (p = i->ops->get_modinfo(i, &size);
                     p;
                     p = next_string(p, &size)) {
                        if (strncmp(p, "alias=", strlen("alias=")) == 0)
                                fprintf(out, "alias %s %s\n",
                                        p + strlen("alias="), modname);
                }
        }
}

struct depfile {
        char *name;
        void (*func)(struct module *, FILE *);
};

static struct depfile depfiles[] = {
        { "modules.dep", output_deps }, /* This is what we check for '-A'. */
        { "modules.pcimap", output_pci_table },
        { "modules.usbmap", output_usb_table },
        { "modules.ccwmap", output_ccw_table },
        { "modules.ieee1394map", output_ieee1394_table },
        { "modules.isapnpmap", output_isapnp_table },
        { "modules.inputmap", output_input_table },
        { "modules.ofmap", output_of_table },
        { "modules.seriomap", output_serio_table },
        { "modules.alias", output_aliases },
        { "modules.symbols", output_symbols },
};

/* If we can't figure it out, it's safe to say "true". */
static int any_modules_newer(const char *dirname, time_t mtime)
{
        DIR *dir;
        struct dirent *dirent;

        dir = opendir(dirname);
        if (!dir)
                return 1;

        while ((dirent = readdir(dir)) != NULL) {
                struct stat st;
                char file[strlen(dirname) + 1 + strlen(dirent->d_name) + 1];

                if (streq(dirent->d_name, ".") || streq(dirent->d_name, ".."))
                        continue;

                sprintf(file, "%s/%s", dirname, dirent->d_name);
                if (lstat(file, &st) != 0)
                        return 1;

                if (smells_like_module(dirent->d_name)) {
                        if (st.st_mtime > mtime)
                                return 1;
                } else if (S_ISDIR(st.st_mode)) {
                        if (any_modules_newer(file, mtime))
                                return 1;
                }
        }
        closedir(dir);
        return 0;
}

static int depfile_out_of_date(const char *dirname)
{
        struct stat st;
        char depfile[strlen(dirname) + 1 + strlen(depfiles[0].name) + 1];

        sprintf(depfile, "%s/%s", dirname, depfiles[0].name);

        if (stat(depfile, &st) != 0)
                return 1;

        return any_modules_newer(dirname, st.st_mtime);
}

static int fgetc_wrapped(FILE *file, unsigned int *linenum)
{
        for (;;) {
                int ch = fgetc(file);
                if (ch != '\\')
                        return ch;
                ch = fgetc(file);
                if (ch != '\n')
                        return ch;
                if (linenum)
                        (*linenum)++;
        }
}

static char *getline_wrapped(FILE *file, unsigned int *linenum)
{
        int size = 1024;
        int i = 0;
        char *buf = NOFAIL(malloc(size));
        for(;;) {
                int ch = fgetc_wrapped(file, linenum);
                if (i == size) {
                        size *= 2;
                        buf = NOFAIL(realloc(buf, size));
                }
                if (ch < 0 && i == 0) {
                        free(buf);
                        return NULL;
                }
                if (ch < 0 || ch == '\n') {
                        if (linenum)
                                (*linenum)++;
                        buf[i] = '\0';
                        return NOFAIL(realloc(buf, i+1));
                }
                buf[i++] = ch;
        }
}


static char *strsep_skipspace(char **string, char *delim)
{
        if (!*string)
                return NULL;
        *string += strspn(*string, delim);
        return strsep(string, delim);
}

static struct module_search *add_search(const char *search_path,
                                        struct module_search *search)
{

        struct module_search *new;
        
        new = NOFAIL(malloc(sizeof(*new)));
        new->search_path = NOFAIL(strdup(search_path));
        new->next = search;

        return new;
        
}

static struct module_overrides *add_override(const char *modfile,
                                             struct module_overrides *overrides)
{

        struct module_overrides *new;
        
        new = NOFAIL(malloc(sizeof(*new)));
        new->modfile = NOFAIL(strdup(modfile));
        new->next = overrides;

        return new;
        
}

/* Recursion */
static int read_config(const char *filename,
                       const char *basedir,
                       struct module_search **search,
                       struct module_overrides **overrides);

static int read_config_file(const char *filename,
                            const char *basedir,
                            struct module_search **search,
                            struct module_overrides **overrides)
{
        char *line;
        unsigned int linenum = 0;
        FILE *cfile;

        cfile = fopen(filename, "r");
        if (!cfile) {
                if (errno != ENOENT)
                        fatal("could not open '%s', reason: %s\n", filename,
                              strerror(errno));
                return 0;
        }

        while ((line = getline_wrapped(cfile, &linenum)) != NULL) {
                char *ptr = line;
                char *cmd, *modname;

                cmd = strsep_skipspace(&ptr, "\t ");

                if (cmd == NULL || cmd[0] == '#' || cmd[0] == '\0')
                        continue;

                if (strcmp(cmd, "search") == 0) {
                        char *search_path;
                        
                        while ((search_path = strsep_skipspace(&ptr, "\t ")))
                                *search = add_search(search_path, *search);
                } else if (strcmp(cmd, "override") == 0) {
                        char *pathname = NULL, *version, *subdir;
                        modname = strsep_skipspace(&ptr, "\t ");
                        version = strsep_skipspace(&ptr, "\t ");
                        subdir = strsep_skipspace(&ptr, "\t ");

                        pathname = NOFAIL(malloc(strlen(basedir)
                                               + strlen(MODULE_DIR)
                                               + strlen(version)
                                               + strlen(subdir)
                                               + strlen(modname)
                                               + strlen(".ko")
                                               + 3));
                        sprintf(pathname, "%s%s%s/%s/%s.ko", basedir,
                                MODULE_DIR, version, subdir, modname);

                        *overrides = add_override(pathname, *overrides);
                } else if (strcmp(cmd, "include") == 0) {
                        char *newfilename;

                        newfilename = strsep_skipspace(&ptr, "\t ");
                        if (!newfilename)
                                grammar(cmd, filename, linenum);
                        else {
                                if (!read_config(newfilename, basedir,
                                                 search, overrides))
                                        warn("Failed to open included"
                                             " config file %s: %s\n",
                                             newfilename, strerror(errno));
                        }
                } else
                        grammar(cmd, filename, linenum);

                free(line);
        }
        fclose(cfile);
        return 1;
}

/* Simple format, ignore lines starting with #, one command per line.
   Returns true or false. */
static int read_config(const char *filename,
                       const char *basedir,
                       struct module_search **search,
                       struct module_overrides **overrides)
{
        DIR *dir;
        int ret = 0;

        dir = opendir(filename);
        if (dir) {
                struct dirent *i;
                while ((i = readdir(dir)) != NULL) {
                        if (!streq(i->d_name,".") && !streq(i->d_name,"..")) {
                                char sub[strlen(filename) + 1
                                       + strlen(i->d_name) + 1];

                                sprintf(sub, "%s/%s", filename, i->d_name);
                                if (!read_config(sub, basedir, search,
                                                 overrides))
                                        warn("Failed to open"
                                             " config file %s: %s\n",
                                             sub, strerror(errno));
                        }
                }
                closedir(dir);
                ret = 1;
        } else {
                if (read_config_file(filename, basedir, search, overrides))
                        ret = 1;
        }

        return ret;
}

static const char *default_configs[] =
{
        "/etc/depmod.conf",
        "/etc/depmod.d",
};

static void read_toplevel_config(const char *filename,
                                 const char *basedir,
                                 struct module_search **search,
                                 struct module_overrides **overrides)
{
        unsigned int i;

        if (filename) {
                if (!read_config(filename, basedir, search, overrides))
                        fatal("Failed to open config file %s: %s\n",
                              filename, strerror(errno));
                return;
        }

        /* Try defaults. */
        for (i = 0; i < ARRAY_SIZE(default_configs); i++) {
                if (read_config(default_configs[i], basedir, search, overrides))
                        return;
        }
}


int main(int argc, char *argv[])
{
        int opt, all = 0, maybe_all = 0, doing_stdout = 0;
        char *basedir = "", *dirname, *version, *badopt = NULL,
                *system_map = NULL;
        struct module *list = NULL;
        int i;
        const char *config = NULL;
        struct module_search *search = NULL;
        struct module_overrides *overrides = NULL;

        /* Don't print out any errors just yet, we might want to exec
           backwards compat version. */
        opterr = 0;
        while ((opt = getopt_long(argc, argv, "ab:ArehnqruvVF:C:", options, NULL))
               != -1) {
                switch (opt) {
                case 'a':
                        all = 1;
                        break;
                case 'b':
                        basedir = optarg;
                        skipchars = strlen(basedir);
                        break;
                case 'A':
                        maybe_all = 1;
                        break;
                case 'F':
                        system_map = optarg;
                        break;
                case 'e':
                        print_unknown = 1;
                        break;
                case 'v':
                        verbose = 1;
                        break;
                case 'u':
                case 'q':
                case 'r':
                        break;
                case 'C':
                        config = optarg;
                        break;
                case 'h':
                        print_usage(argv[0]);
                        exit(0);
                        break;
                case 'n':
                        doing_stdout = 1;
                        break;
                case 'V':
                        printf("%s %s\n", PACKAGE, VERSION);
                        exit(0);
                default:
                        badopt = argv[optind-1];
                }
        }

        /* We can't print unknowns without a System.map */
        if (!system_map)
                print_unknown = 0;
        else
                load_system_map(system_map);

        /* They can specify the version naked on the command line */
        if (optind < argc && is_version_number(argv[optind])) {
                version = NOFAIL(strdup(argv[optind]));
                optind++;
        } else {
                struct utsname buf;
                uname(&buf);
                version = NOFAIL(strdup(buf.release));
        }

        /* Run old version if required. */
        if (old_module_version(version))
                exec_old_depmod(argv);

        if (badopt) {
                fprintf(stderr, "%s: malformed/unrecognized option '%s'\n",
                        argv[0], badopt);
                print_usage(argv[0]);
                exit(1);
        }

        /* Depmod -a by default if no names. */
        if (optind == argc)
                all = 1;

        dirname = NOFAIL(malloc(strlen(basedir)
                         + strlen(MODULE_DIR)
                         + strlen(version) + 1));
        sprintf(dirname, "%s%s%s", basedir, MODULE_DIR, version);

        if (maybe_all) {
                if (!doing_stdout && !depfile_out_of_date(dirname))
                        exit(0);
                all = 1;
        }

        read_toplevel_config(config, basedir, &search, &overrides);

        /* For backward compatibility add "updates" to the head of the search
         * list here. But only if there was no "search" option specified.
         */

        if (!search)
                search = add_search("updates",search);
        
        if (!all) {
                /* Do command line args. */
                for (opt = optind; opt < argc; opt++) {
                        struct module *new = grab_module(NULL, argv[opt]);
                        if (new) {
                                new->next = list;
                                list = new;
                        }
                }
        } else {
                list = grab_basedir(dirname,search,overrides);
        }
        parse_modules(list);

        for (i = 0; i < sizeof(depfiles)/sizeof(depfiles[0]); i++) {
                FILE *out;
                struct depfile *d = &depfiles[i];
                char depname[strlen(dirname) + 1 + strlen(d->name) + 1];
                char tmpname[strlen(dirname) + 1 + strlen(d->name) +
                                                strlen(".temp") + 1];

                sprintf(depname, "%s/%s", dirname, d->name);
                sprintf(tmpname, "%s/%s.temp", dirname, d->name);
                if (!doing_stdout) {
                        out = fopen(tmpname, "w");
                        if (!out)
                                fatal("Could not open %s for writing: %s\n",
                                        tmpname, strerror(errno));
                } else
                        out = stdout;
                d->func(list, out);
                if (!doing_stdout) {
                        fclose(out);
                        if (rename(tmpname, depname) < 0)
                                fatal("Could not rename %s into %s: %s\n",
                                        tmpname, depname, strerror(errno));
                }
        }

        free(dirname);
        free(version);
        
        return 0;
}