lib/libdevinfo/devinfo_devlink.h

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 * Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 */


#ifndef _DEVINFO_DEVLINK_H
#define _DEVINFO_DEVLINK_H

#ifdef  __cplusplus
extern "C" {
#endif

#define _POSIX_PTHREAD_SEMANTICS    /* For readdir_r */

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <thread.h>
#include <synch.h>
#include <libdevinfo.h>
#include <limits.h>
#include <stdlib.h>
#include <dirent.h>
#include <regex.h>
#include <errno.h>
#include <stdarg.h>
#include <sys/uio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <door.h>
#include <signal.h>
#include <sys/statvfs.h>

struct db_link {
    uint32_t attr;      /* primary or secondary */
    uint32_t path;      /* link path */
    uint32_t content;   /* link content */
    uint32_t sib;       /* next link for same minor */
};

struct db_minor {
    uint32_t name;      /* minor name */
    uint32_t nodetype;  /* minor node type */
    uint32_t sib;       /* next minor for same node */
    uint32_t link;      /* next minor for same node */
};

struct db_node {
    uint32_t path;      /* node path */
    uint32_t sib;       /* node's sibling */
    uint32_t child;     /* first child for this node */
    uint32_t minor;     /* first minor for node */
};

typedef enum db_seg {
    DB_NODE = 0,
    DB_MINOR,
    DB_LINK,
    DB_STR,
    DB_TYPES,   /* Number of non-header segments */
    DB_HEADER
} db_seg_t;

struct db_hdr {
    uint32_t magic;         /* Magic number */
    uint32_t vers;          /* database format version */
    uint32_t root_idx;      /* index for root node */
    uint32_t dngl_idx;      /* head of DB dangling links */
    uint32_t page_sz;       /* page size for mmap alignment */
    uint32_t update_count;      /* updates since last /dev synch up */
    uint32_t nelems[DB_TYPES];  /* Number of elements of each type */
};


typedef struct cache_link {
    char   *path;           /* link path */
    char   *content;        /* link content */
    uint_t attr;            /* link attributes */
    struct cache_link *hash;    /* next link on same hash chain */
    struct cache_link *sib;     /* next link for same minor */
    struct cache_minor *minor;  /* minor for this link */
} cache_link_t;

typedef struct cache_minor {
    char *name;         /* minor name */
    char *nodetype;         /* minor nodetype */
    struct cache_node *node;    /* node for this minor */
    struct cache_minor *sib;    /* next minor for same node */
    struct cache_link *link;    /* first link pointing to minor */
} cache_minor_t;

typedef struct cache_node {
    char    *path;          /* path */
    struct cache_node *parent;  /* node's parent */
    struct cache_node *sib;     /* node's sibling */
    struct cache_node *child;   /* first child for this node */
    struct cache_minor *minor;  /* first minor for node */
} cache_node_t;

struct cache {
    uint_t  flags;          /* cache state */
    uint_t  update_count;       /* updates since /dev synchronization */
    uint_t  hash_sz;        /* number of hash chains */
    cache_link_t **hash;        /* hash table */
    cache_node_t *root;     /* root of cache tree */
    cache_link_t *dngl;     /* list of dangling links */
    cache_minor_t *last_minor;  /* last minor looked up */
};

struct db {
    int db_fd;          /* database file */
    uint_t flags;           /* database open mode */
    struct db_hdr *hdr;     /* DB header */
    int  seg_prot[DB_TYPES];    /* protection for  segments */
    caddr_t seg_base[DB_TYPES]; /* base address for segments */
};

struct di_devlink_handle {
    char *dev_dir;          /* <root-dir>/dev */
    char *db_dir;           /* <root-dir>/etc/dev */
    uint_t  flags;          /* handle flags */
    uint_t  error;          /* records errors encountered */
    int lock_fd;            /* lock file for updates */
    struct cache cache;
    struct db db;
};

typedef struct link_desc {
    regex_t *regp;
    const char *minor_path;
    uint_t flags;
    void *arg;
    int (*fcn)(di_devlink_t, void *);
    int retval;
} link_desc_t;

struct tnode {
    void *node;
    int flags;
    struct di_devlink_handle *handle;
};

struct di_devlink {
    char *rel_path;
    char *abs_path;
    char *content;
    int type;
};

typedef struct recurse {
    void *data;
    int (*fcn)(struct di_devlink_handle *, void *, const char *);
} recurse_t;

/*
 * Debug levels currently defined.
 */
typedef enum {
    DBG_ERR = 1,
    DBG_LCK,
    DBG_INFO,
    DBG_STEP,
    DBG_ALL
} debug_level_t;


#define DB_MAGIC    0xBAC2ACAB
#define DB_FILE     ".devlink_db"
#define DB_TMP      ".devlink_db_tmp"
#define DB_LOCK     ".devlink_db_lock"
#define DB_PERMS    (S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR)
#define DB_LOCK_PERMS   DB_PERMS
#define DB_VERSION  1

#define DB_NIL      0

#define DEV     "/dev"
#define ETCDEV      "/etc/dev"
#define DEVICES_SUFFIX  "ices"

#define HDR_LEN         sizeof (struct db_hdr)

#define AVG_CHAIN_SIZE      20   /* Average number of links per chain */
#define MIN_HASH_SIZE       1024 /* Min number of chains in hash table */
#define MAX_UPDATE_INTERVAL 5 /* Max DB writes before synching with /dev */
#define MAX_LOCK_RETRY      5 /* Max attempts at locking the update lock */

/*
 * Various flags private to the implementation
 */
#define A_PRIMARY       0x0001U
#define A_SECONDARY     0x0002U
#define A_LINK_TYPES        0x0003U /* Mask */
#define A_VALID         0x0004U

#define TYPE_DB         0x0008U
#define TYPE_CACHE      0x0010U
#define CREATE_FLAG     0x0020U

#define INSERT_HEAD     0x0040U
#define INSERT_TAIL     0x0080U
#define OPEN_RDWR       0x0100U
#define OPEN_RDONLY     0x0200U
#define OPEN_FLAGS      0x0300U /* Mask */
#define UNLINK_FROM_HASH    0x0400U

#define SET_VALID_ATTR(a)   ((a) |= A_VALID)
#define CLR_VALID_ATTR(a)   ((a) &= ~A_VALID)
#define GET_VALID_ATTR(a)   ((a) & A_VALID)

#define SET_DB_ERR(h)   ((h)->error = 1)
#define DB_ERR(h)   ((h)->error)

#define LOOKUP_DB(f)    ((f) & TYPE_DB)
#define LOOKUP_CACHE(f) ((f) & TYPE_CACHE)
#define CREATE_ELEM(f)  ((f) & CREATE_FLAG)

#define IS_RDWR(f)  (((f) & OPEN_FLAGS) == OPEN_RDWR)
#define IS_RDONLY(f)    (((f) & OPEN_FLAGS) == OPEN_RDONLY)

#define HDL_RDWR(h) (((h)->flags & OPEN_FLAGS) == OPEN_RDWR)
#define HDL_RDONLY(h)   (((h)->flags & OPEN_FLAGS) == OPEN_RDONLY)

#define CACHE(h)        (&(h)->cache)
#define CACHE_ROOT(h)       (CACHE(h)->root)
#define CACHE_HASH(h, i)    (CACHE(h)->hash[i])
#define CACHE_LAST(h)   (CACHE(h)->last_minor)
#define CACHE_EMPTY(h)  (CACHE(h)->root == NULL && CACHE(h)->dngl == NULL)

#define DB(h)           (&(h)->db)
#define DB_HDR(h)       (DB(h)->hdr)
#define DB_NUM(h, t)        (DB_HDR(h)->nelems[t])
#define DB_SEG(h, t)        (DB(h)->seg_base[t])
#define DB_SEG_PROT(h, t)   (DB(h)->seg_prot[t])

#define DB_OPEN(h)  (DB_HDR(h) != NULL)
#define DB_RDWR(h)  ((DB(h)->flags & OPEN_FLAGS) == OPEN_RDWR)
#define DB_RDONLY(h)    ((DB(h)->flags & OPEN_FLAGS) == OPEN_RDONLY)

#define DB_EMPTY(h) (DB_HDR(h)->root_idx == DB_NIL && \
                DB_HDR(h)->dngl_idx == DB_NIL)

#define TYPE_NONE(f)    (((f) & DI_LINK_TYPES) == 0)
#define TYPE_PRI(f) (((f) & DI_LINK_TYPES) == DI_PRIMARY_LINK)
#define TYPE_SEC(f) (((f) & DI_LINK_TYPES) == DI_SECONDARY_LINK)
#define LINK_TYPE(f)    ((f) & DI_LINK_TYPES)
#define VALID_TYPE(f)   (TYPE_NONE(f) || TYPE_PRI(f) || TYPE_SEC(f))

#define VALID_STR(h, i, s)   ((i) + strlen(s) + 1 <= DB_HDR(h)->nelems[DB_STR])
#define VALID_INDEX(h, t, i) ((i) < DB_HDR(h)->nelems[t])

/*
 * Environment variables used by DEBUG version of code.
 */
#define SKIP_DB     "DEBUG_SKIP_DB"
#define SKIP_LAST_CACHE "DEBUG_SKIP_LAST_CACHE"
#define ALT_DB_DIR  "DEBUG_ALT_DB_DIR"

/*
 * Function prototypes
 */
static struct di_devlink_handle *handle_alloc(const char *dev_dir,
    uint_t flags);
static int cache_alloc(struct di_devlink_handle *hdp);
static int open_db(struct di_devlink_handle *hdp, int flags);
static int invalid_db(struct di_devlink_handle *hdp, size_t fsize, long pg_sz);
static int read_nodes(struct di_devlink_handle *hdp, cache_node_t *pcnp,
    uint32_t nidx);
static int read_minors(struct di_devlink_handle *hdp, cache_node_t *pcnp,
    uint32_t nidx);
static int read_links(struct di_devlink_handle *hdp, cache_minor_t *pcmp,
    uint32_t nidx);
static int init_hdr(struct di_devlink_handle *hdp, long page_sz,
    uint32_t *count);
static size_t size_db(struct di_devlink_handle *hdp, long page_sz,
    uint32_t *count);
static size_t seg_size(struct di_devlink_handle *hdp, int seg);

static cache_node_t *node_insert(struct di_devlink_handle *hdp,
    cache_node_t *pcnp, const char *path, int insert);
static cache_minor_t *minor_insert(struct di_devlink_handle *hdp,
    cache_node_t *pcnp, const char *name, const char *nodetype,
    cache_minor_t **prev);
static cache_link_t *link_insert(struct di_devlink_handle *hdp,
    cache_minor_t *mnp, const char *path, const char *content, uint32_t attr);

static void minor_delete(di_devlink_handle_t hdp, cache_minor_t *cmnp);
static void link_delete(di_devlink_handle_t hdp, cache_link_t *clp);

static int write_nodes(struct di_devlink_handle *hdp, struct db_node *pdnp,
    cache_node_t *cnp, uint32_t *next);
static int write_minors(struct di_devlink_handle *hdp, struct db_node *pdnp,
    cache_minor_t *cmnp, uint32_t *next);
static int write_links(struct di_devlink_handle *hdp, struct db_minor *pdmp,
    cache_link_t *clp, uint32_t *next);
static void rm_link_from_hash(struct di_devlink_handle *hdp, cache_link_t *clp);
static uint32_t write_string(struct di_devlink_handle *hdp, const char *str,
    uint32_t *next);
static int close_db(struct di_devlink_handle *hdp);
static void cache_free(struct di_devlink_handle *hdp);
static void handle_free(struct di_devlink_handle **pp);
static void resolve_dangling_links(struct di_devlink_handle *hdp);
static void subtree_free(struct di_devlink_handle *hdp, cache_node_t **pp);
static void node_free(cache_node_t **pp);
static void minor_free(struct di_devlink_handle *hdp, cache_minor_t **pp);
static void link_free(cache_link_t **pp);
static void count_node(cache_node_t *cnp, uint32_t *count);
static void count_minor(cache_minor_t *mnp, uint32_t *count);
static void count_link(cache_link_t *clp, uint32_t *count);
static void count_string(const char *str, uint32_t *count);
static int visit_node(const char *path, void *arg);
static int walk_tree(char *cur, void *arg,
    int (*node_callback)(const char *path, void *arg));
static void *lookup_node(struct di_devlink_handle *hdp, char *path,
    const int flags);
static cache_link_t *add_link(struct di_devlink_handle *hdp, const char *link,
    const char *content, int primary);

static void *lookup_minor(struct di_devlink_handle *hdp, const char *minor_path,
    const char *nodetype, const int flags);
static cache_link_t *link_hash(di_devlink_handle_t hdp, const char *link,
    uint_t flags);

static void hash_insert(struct di_devlink_handle *hdp, cache_link_t *clp);
static uint_t hashfn(struct di_devlink_handle *hdp, const char *str);
static void get_db_path(struct di_devlink_handle *hdp, const char *fname,
    char *buf, size_t blen);

static struct db_node *get_node(struct di_devlink_handle *hdp, uint32_t idx);
static struct db_node *set_node(struct di_devlink_handle *hdp, uint32_t idx);

static struct db_minor *get_minor(struct di_devlink_handle *hdp, uint32_t idx);
static struct db_minor *set_minor(struct di_devlink_handle *hdp, uint32_t idx);

static struct db_link *get_link(struct di_devlink_handle *hdp, uint32_t idx);
static struct db_link *set_link(struct di_devlink_handle *hdp, uint32_t idx);

static char *get_string(struct di_devlink_handle *hdp, uint32_t idx);
static char *set_string(struct di_devlink_handle *hdp, uint32_t idx);

static void *map_seg(struct di_devlink_handle *hdp, uint32_t idx, int prot,
    db_seg_t seg);

static int walk_db(struct di_devlink_handle *hdp, link_desc_t *linkp);
static int walk_all_links(struct di_devlink_handle *hdp, link_desc_t *linkp);
static int walk_matching_links(struct di_devlink_handle *hdp,
    link_desc_t *linkp);
static int visit_link(struct di_devlink_handle *hdp, link_desc_t *linkp,
    struct di_devlink *vlp);

static void walk_cache_minor(di_devlink_handle_t hdp, const char *mpath,
    link_desc_t *linkp);
static int walk_cache_links(di_devlink_handle_t hdp, cache_link_t *clp,
    link_desc_t *linkp);
static void walk_all_cache(di_devlink_handle_t hdp, link_desc_t *linkp);
static int cache_dev_link(struct di_devlink_handle *hdp, void *data,
    const char *link_path);

static int walk_dev(struct di_devlink_handle *hdp, link_desc_t *linkp);
static int recurse_dev(struct di_devlink_handle *hdp, recurse_t *rp);
static int do_recurse(const char *dir, struct di_devlink_handle *hdp,
    recurse_t *rp, int *retp);

static int check_attr(uint32_t attr);
static int attr2type(uint32_t attr);

static int check_args(link_desc_t *linkp);

static void *get_last_node(struct di_devlink_handle *hdp, const char *path,
    int flags);
static void *get_last_minor(struct di_devlink_handle *hdp,
    const char *devfs_path, const char *minor_name, int flags);
static void set_last_minor(struct di_devlink_handle *hdp, cache_minor_t *cmnp,
    int flags);

static int enter_db_lock(struct di_devlink_handle *hdp, const char *root_dir);
static void exit_db_lock(struct di_devlink_handle *hdp);

static char *minor_colon(const char *path);
static const char *rel_path(struct di_devlink_handle *hdp, const char *path);
static int link_flag(uint_t flags);
static int s_readlink(const char *link, char *buf, size_t blen);
static cache_minor_t *link2minor(struct di_devlink_handle *hdp,
    cache_link_t *clp);
static int link_cmp(cache_link_t *clp, const char *content, int type);
static void delete_unused_nodes(di_devlink_handle_t hdp, cache_node_t *cnp);
static void delete_unused_minor(di_devlink_handle_t hdp, cache_minor_t *cmnp);
static int synchronize_db(di_devlink_handle_t hdp);
static void dprintf(debug_level_t msglevel, const char *fmt, ...);
static di_devlink_handle_t devlink_snapshot(const char *root_dir);
static int devlink_create(const char *root, const char *name, int dca_flags);
static int dca_init(const char *name, struct dca_off *dcp, int dca_flags);
static void exec_devfsadm(const char *root, struct dca_off *dcp);
static int do_exec(const char *path, char *const argv[]);
static int daemon_call(const char *root, struct dca_off *dcp);

int is_minor_node(const char *contents, const char **mn_root);
char *s_realpath(const char *path, char *resolved_path);

#ifdef  __cplusplus
}
#endif

#endif /* _DEVINFO_DEVLINK_H */