libs/light/libxl_utils.c

/*
 * Copyright (C) 2009      Citrix Ltd.
 * Author Stefano Stabellini <stefano.stabellini@eu.citrix.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; version 2.1 only. with the special
 * exception on linking described in file LICENSE.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 */

#include "libxl_osdeps.h" /* must come before any other headers */

#include <ctype.h>

#include "libxl_internal.h"

#ifndef LIBXL_HAVE_NONCONST_LIBXL_BASENAME_RETURN_VALUE
const
#endif
char *libxl_basename(const char *name)
{
    const char *filename;
    if (name == NULL)
        return strdup(".");
    if (name[0] == '\0')
        return strdup(".");

    filename = strrchr(name, '/');
    if (filename)
        return strdup(filename+1);
    return strdup(name);
}

unsigned long libxl_get_required_shadow_memory(unsigned long maxmem_kb, unsigned int smp_cpus)
{
    return libxl__get_required_paging_memory(maxmem_kb, smp_cpus,
                                             LIBXL_DOMAIN_TYPE_INVALID, false);
}

char *libxl_domid_to_name(libxl_ctx *ctx, uint32_t domid)
{
    unsigned int len;
    char path[sizeof("/local/domain") + 11];
    char *s;

    snprintf(path, sizeof(path), "/local/domain/%d/name", domid);
    s = xs_read(ctx->xsh, XBT_NULL, path, &len);
    return s;
}

char *libxl__domid_to_name(libxl__gc *gc, uint32_t domid)
{
    char *s = libxl_domid_to_name(CTX, domid);
    libxl__ptr_add(gc, s);
    return s;
}

int libxl_name_to_domid(libxl_ctx *ctx, const char *name,
                        uint32_t *domid)
{
    int i, nb_domains;
    char *domname;
    libxl_dominfo *dominfo;
    int ret = ERROR_INVAL;

    dominfo = libxl_list_domain(ctx, &nb_domains);
    if (!dominfo)
        return ERROR_NOMEM;

    for (i = 0; i < nb_domains; i++) {
        domname = libxl_domid_to_name(ctx, dominfo[i].domid);
        if (!domname)
            continue;
        if (strcmp(domname, name) == 0) {
            *domid = dominfo[i].domid;
            ret = 0;
            free(domname);
            break;
        }
        free(domname);
    }
    libxl_dominfo_list_free(dominfo, nb_domains);
    return ret;
}

int libxl_domain_qualifier_to_domid(libxl_ctx *ctx, const char *name,
                                    uint32_t *domid)
{
    int i, rv;
    for (i=0; name[i]; i++) {
        if (!CTYPE(isdigit, name[i])) {
            goto nondigit_found;
        }
    }
    *domid = strtoul(name, NULL, 10);
    return 0;

 nondigit_found:
    /* this could also check for uuids */
    rv = libxl_name_to_domid(ctx, name, domid);
    return rv;
}

static int qualifier_to_id(const char *p, uint32_t *id_r)
{
    int i, alldigit;

    alldigit = 1;
    for (i = 0; p[i]; i++) {
        if (!isdigit((uint8_t)p[i])) {
            alldigit = 0;
            break;
        }
    }

    if (i > 0 && alldigit) {
        *id_r = strtoul(p, NULL, 10);
        return 0;
    } else {
        /* check here if it's a uuid and do proper conversion */
    }
    return 1;
}

int libxl_cpupool_qualifier_to_cpupoolid(libxl_ctx *ctx, const char *p,
                                         uint32_t *poolid_r,
                                         int *was_name_r)
{
    int was_name;

    was_name = qualifier_to_id(p, poolid_r);
    if (was_name_r) *was_name_r = was_name;
    return was_name ? libxl_name_to_cpupoolid(ctx, p, poolid_r) : 0;
}

char *libxl_cpupoolid_to_name(libxl_ctx *ctx, uint32_t poolid)
{
    unsigned int len;
    char path[sizeof("/local/pool") + 11];
    char *s;

    snprintf(path, sizeof(path), "/local/pool/%d/name", poolid);
    s = xs_read(ctx->xsh, XBT_NULL, path, &len);

    return s;
}

/* This is a bit horrid but without xs_exists it seems like the only way. */
int libxl_cpupoolid_is_valid(libxl_ctx *ctx, uint32_t poolid)
{
    int ret;
    char *s = libxl_cpupoolid_to_name(ctx, poolid);

    ret = (s != NULL);
    free(s);
    return ret;
}

char *libxl__cpupoolid_to_name(libxl__gc *gc, uint32_t poolid)
{
    char *s = libxl_cpupoolid_to_name(CTX, poolid);
    libxl__ptr_add(gc, s);
    return s;
}

int libxl_name_to_cpupoolid(libxl_ctx *ctx, const char *name,
                        uint32_t *poolid)
{
    int i, nb_pools;
    char *poolname;
    libxl_cpupoolinfo *poolinfo;
    int ret = ERROR_INVAL;

    poolinfo = libxl_list_cpupool(ctx, &nb_pools);
    if (!poolinfo)
        return ERROR_NOMEM;

    for (i = 0; i < nb_pools; i++) {
        if (ret && ((poolname = libxl_cpupoolid_to_name(ctx,
            poolinfo[i].poolid)) != NULL)) {
            if (strcmp(poolname, name) == 0) {
                *poolid = poolinfo[i].poolid;
                ret = 0;
            }
            free(poolname);
        }
    }
    libxl_cpupoolinfo_list_free(poolinfo, nb_pools);
    return ret;
}

int libxl_get_stubdom_id(libxl_ctx *ctx, int guest_domid)
{
    GC_INIT(ctx);
    char * stubdom_id_s;
    int ret;

    stubdom_id_s = libxl__xs_read(gc, XBT_NULL,
                                  GCSPRINTF("%s/image/device-model-domid",
                                  libxl__xs_get_dompath(gc, guest_domid)));
    if (stubdom_id_s)
        ret = atoi(stubdom_id_s);
    else
        ret = 0;
    GC_FREE;
    return ret;
}

int libxl_is_stubdom(libxl_ctx *ctx, uint32_t domid, uint32_t *target_domid)
{
    GC_INIT(ctx);
    char *target, *endptr;
    uint32_t value;
    int ret = 0;

    target = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("%s/target",
                            libxl__xs_get_dompath(gc, domid)));
    if (!target)
        goto out;
    value = strtol(target, &endptr, 10);
    if (*endptr != '\0')
        goto out;
    if (target_domid)
        *target_domid = value;
    ret = 1;
out:
    GC_FREE;
    return ret;
}

static int logrename(libxl__gc *gc, const char *old, const char *new)
{
    int r;

    r = rename(old, new);
    if (r) {
        if (errno == ENOENT) return 0; /* ok */

        LOGE(ERROR, "failed to rotate logfile - "
                    "could not rename %s to %s", old, new);
        return ERROR_FAIL;
    }
    return 0;
}

int libxl_create_logfile(libxl_ctx *ctx, const char *name, char **full_name)
{
    GC_INIT(ctx);
    struct stat stat_buf;
    char *logfile, *logfile_new;
    int i, rc;

    logfile = GCSPRINTF(XEN_LOG_DIR "/%s.log", name);
    if (stat(logfile, &stat_buf) == 0) {
        /* file exists, rotate */
        logfile = GCSPRINTF(XEN_LOG_DIR "/%s.log.10", name);
        unlink(logfile);
        for (i = 9; i > 0; i--) {
            logfile = GCSPRINTF(XEN_LOG_DIR "/%s.log.%d", name, i);
            logfile_new = GCSPRINTF(XEN_LOG_DIR "/%s.log.%d", name, i + 1);
            rc = logrename(gc, logfile, logfile_new);
            if (rc)
                goto out;
        }
        logfile = GCSPRINTF(XEN_LOG_DIR "/%s.log", name);
        logfile_new = GCSPRINTF(XEN_LOG_DIR "/%s.log.1", name);

        rc = logrename(gc, logfile, logfile_new);
        if (rc)
            goto out;
    } else {
        if (errno != ENOENT)
            LOGE(WARN, "problem checking existence of logfile %s, "
                       "which might have needed to be rotated",
                 name);
    }
    *full_name = strdup(logfile);
    rc = 0;
out:
    GC_FREE;
    return rc;
}

int libxl_string_to_backend(libxl_ctx *ctx, char *s, libxl_disk_backend *backend)
{
    char *p;
    int rc = 0;

    if (!strcmp(s, "phy")) {
        *backend = LIBXL_DISK_BACKEND_PHY;
    } else if (!strcmp(s, "file")) {
        *backend = LIBXL_DISK_BACKEND_TAP;
    } else if (!strcmp(s, "vbd3")) {
        *backend = LIBXL_DISK_BACKEND_TAP;
    } else if (!strcmp(s, "qdisk")) {
        *backend = LIBXL_DISK_BACKEND_QDISK;
    } else if (!strcmp(s, "standalone")) {
        *backend = LIBXL_DISK_BACKEND_STANDALONE;
    } else if (!strcmp(s, "tap")) {
        p = strchr(s, ':');
        if (!p) {
            rc = ERROR_INVAL;
            goto out;
        }
        p++;
        if (!strcmp(p, "vhd")) {
            *backend = LIBXL_DISK_BACKEND_TAP;
        } else if (!strcmp(p, "qcow")) {
            *backend = LIBXL_DISK_BACKEND_QDISK;
        } else if (!strcmp(p, "qcow2")) {
            *backend = LIBXL_DISK_BACKEND_QDISK;
        } else if (!strcmp(p, "qed")) {
            *backend = LIBXL_DISK_BACKEND_QDISK;
        }
    }
out:
    return rc;
}

int libxl_read_file_contents(libxl_ctx *ctx, const char *filename,
                             void **data_r, int *datalen_r) {
    GC_INIT(ctx);
    FILE *f = 0;
    uint8_t *data = 0;
    int datalen = 0;
    int e;
    struct stat stab;
    ssize_t rs;

    f = fopen(filename, "r");
    if (!f) {
        if (errno == ENOENT) return ENOENT;
        LOGE(ERROR, "failed to open %s", filename);
        goto xe;
    }

    if (fstat(fileno(f), &stab)) {
        LOGE(ERROR, "failed to fstat %s", filename);
        goto xe;
    }

    if (!S_ISREG(stab.st_mode)) {
        LOGE(ERROR, "%s is not a plain file", filename);
        errno = ENOTTY;
        goto xe;
    }

    if (stab.st_size > INT_MAX) {
        LOG(ERROR, "file %s is far too large", filename);
        errno = EFBIG;
        goto xe;
    }

    datalen = stab.st_size;

    if (stab.st_size && data_r) {
        data = malloc(datalen);
        if (!data) goto xe;

        rs = fread(data, 1, datalen, f);
        if (rs != datalen) {
            if (ferror(f))
                LOGE(ERROR, "failed to read %s", filename);
            else if (feof(f))
                LOG(ERROR, "%s changed size while we were reading it",
		    filename);
            else
                abort();
            goto xe;
        }
    }

    if (fclose(f)) {
        f = 0;
        LOGE(ERROR, "failed to close %s", filename);
        goto xe;
    }

    if (data_r) *data_r = data;
    if (datalen_r) *datalen_r = datalen;

    GC_FREE;
    return 0;

 xe:
    GC_FREE;
    e = errno;
    assert(e != ENOENT);
    if (f) fclose(f);
    free(data);
    return e;
}

int libxl__read_sysfs_file_contents(libxl__gc *gc, const char *filename,
                                    void **data_r, int *datalen_r)
{
    FILE *f = 0;
    uint8_t *data = 0;
    int datalen = 0;
    int e;
    struct stat stab;
    ssize_t rs;

    f = fopen(filename, "r");
    if (!f) {
        if (errno == ENOENT) return ENOENT;
        LOGE(ERROR, "failed to open %s", filename);
        goto xe;
    }

    if (fstat(fileno(f), &stab)) {
        LOGE(ERROR, "failed to fstat %s", filename);
        goto xe;
    }

    if (!S_ISREG(stab.st_mode)) {
        LOGE(ERROR, "%s is not a plain file", filename);
        errno = ENOTTY;
        goto xe;
    }

    if (stab.st_size > INT_MAX) {
        LOG(ERROR, "file %s is far too large", filename);
        errno = EFBIG;
        goto xe;
    }

    datalen = stab.st_size;

    if (stab.st_size && data_r) {
        data = libxl__malloc(gc, datalen);

        /* For sysfs file, datalen is always PAGE_SIZE. 'read'
         * will return the number of bytes of the actual content,
         * rs <= datalen is expected.
         */
        rs = fread(data, 1, datalen, f);
        if (rs < datalen) {
            if (ferror(f)) {
                LOGE(ERROR, "failed to read %s", filename);
                goto xe;
            }

            datalen = rs;
            data = libxl__realloc(gc, data, datalen);
        }
    }

    if (fclose(f)) {
        f = 0;
        LOGE(ERROR, "failed to close %s", filename);
        goto xe;
    }

    if (data_r) *data_r = data;
    if (datalen_r) *datalen_r = datalen;

    return 0;

 xe:
    e = errno;
    assert(e != ENOENT);
    if (f) fclose(f);
    return e;
}


#define READ_WRITE_EXACTLY(rw, zero_is_eof, constdata)                    \
                                                                          \
  int libxl_##rw##_exactly(libxl_ctx *ctx, int fd,                 \
                           constdata void *data, ssize_t sz,              \
                           const char *source, const char *what) {        \
      ssize_t got;                                                        \
      GC_INIT(ctx);                                                       \
                                                                          \
      while (sz > 0) {                                                    \
          got = rw(fd, data, sz);                                         \
          if (got == -1) {                                                \
              if (errno == EINTR) continue;                               \
              if (!ctx) { GC_FREE; return errno; }                        \
              LOGE(ERROR, "failed to "#rw" %s%s%s",                       \
                   what ? what : "", what ? " from " : "", source);       \
              GC_FREE;                                                    \
              return errno;                                               \
          }                                                               \
          if (got == 0) {                                                 \
              if (!ctx) { GC_FREE; return  EPROTO; }                      \
              LOG(ERROR, zero_is_eof                                      \
                  ? "file/stream truncated reading %s%s%s"                \
                  : "file/stream write returned 0! writing %s%s%s",       \
                  what ? what : "", what ? " from " : "", source);        \
              GC_FREE;                                                    \
              return EPROTO;                                              \
          }                                                               \
          sz -= got;                                                      \
          data = (char*)data + got;                                       \
      }                                                                   \
      GC_FREE;                                                            \
      return 0;                                                           \
  }

READ_WRITE_EXACTLY(read, 1, /* */)
READ_WRITE_EXACTLY(write, 0, const)

int libxl__remove_file(libxl__gc *gc, const char *path)
{
    for (;;) {
        int r = unlink(path);
        if (!r) return 0;
        if (errno == ENOENT) return 0;
        if (errno == EINTR) continue;
        LOGE(ERROR, "failed to remove file %s", path);
        return ERROR_FAIL;
     }
}

int libxl__remove_file_or_directory(libxl__gc *gc, const char *path)
{
    for (;;) {
        int r = rmdir(path);
        if (!r) return 0;
        if (errno == ENOENT) return 0;
        if (errno == ENOTEMPTY) return libxl__remove_directory(gc, path);
        if (errno == ENOTDIR) return libxl__remove_file(gc, path);
        if (errno == EINTR) continue;
        LOGE(ERROR, "failed to remove %s", path);
        return ERROR_FAIL;
     }
}

int libxl__remove_directory(libxl__gc *gc, const char *dirpath)
{
    int rc = 0;
    DIR *d = 0;

    d = opendir(dirpath);
    if (!d) {
        if (errno == ENOENT)
            goto out;

        LOGE(ERROR, "failed to opendir %s for removal", dirpath);
        rc = ERROR_FAIL;
        goto out;
    }

    struct dirent *de;

    for (;;) {
        errno = 0;
        de = readdir(d);
        if (!de && errno) {
            LOGE(ERROR, "failed to readdir %s for removal", dirpath);
            rc = ERROR_FAIL;
            break;
        }
        if (!de)
            break;

        if (!strcmp(de->d_name, ".") ||
            !strcmp(de->d_name, ".."))
            continue;

        const char *subpath = GCSPRINTF("%s/%s", dirpath, de->d_name);
        if (libxl__remove_file_or_directory(gc, subpath))
            rc = ERROR_FAIL;
    }

    for (;;) {
        int r = rmdir(dirpath);
        if (!r) break;
        if (errno == ENOENT) goto out;
        if (errno == EINTR) continue;
        LOGE(ERROR, "failed to remove emptied directory %s", dirpath);
        rc = ERROR_FAIL;
        break;
    }

 out:
    if (d) closedir(d);

    return rc;
}

int libxl_pipe(libxl_ctx *ctx, int pipes[2])
{
    GC_INIT(ctx);
    int ret = 0;
    if (pipe(pipes) < 0) {
        LOG(ERROR, "Failed to create a pipe");
        ret = -1;
    }
    GC_FREE;
    return ret;
}

int libxl_bitmap_alloc(libxl_ctx *ctx, libxl_bitmap *bitmap, int n_bits)
{
    GC_INIT(ctx);
    int sz;

    sz = (n_bits + 7) / 8;
    bitmap->map = libxl__calloc(NOGC, sizeof(*bitmap->map), sz);
    bitmap->size = sz;

    GC_FREE;
    return 0;
}

void libxl_bitmap_init(libxl_bitmap *map)
{
    memset(map, '\0', sizeof(*map));
}

void libxl_bitmap_dispose(libxl_bitmap *map)
{
    if (!map)
        return;

    free(map->map);
    map->map = NULL;
    map->size = 0;
}

void libxl_bitmap_copy(libxl_ctx *ctx, libxl_bitmap *dptr,
                       const libxl_bitmap *sptr)
{
    int sz;

    assert(dptr->size == sptr->size);
    sz = dptr->size = sptr->size;
    memcpy(dptr->map, sptr->map, sz * sizeof(*dptr->map));
}

/* This function copies X bytes from source to destination bitmap,
 * where X is the smaller of the two sizes.
 *
 * If destination's size is larger than source, the extra bytes are
 * untouched.
 */
void libxl__bitmap_copy_best_effort(libxl__gc *gc, libxl_bitmap *dptr,
                                    const libxl_bitmap *sptr)
{
    int sz;

    sz = dptr->size < sptr->size ? dptr->size : sptr->size;
    memcpy(dptr->map, sptr->map, sz * sizeof(*dptr->map));
}

void libxl_bitmap_copy_alloc(libxl_ctx *ctx,
                             libxl_bitmap *dptr,
                             const libxl_bitmap *sptr)
{
    GC_INIT(ctx);

    dptr->map = libxl__calloc(NOGC, sptr->size, sizeof(*sptr->map));
    dptr->size = sptr->size;
    memcpy(dptr->map, sptr->map, sptr->size * sizeof(*sptr->map));

    GC_FREE;
}

int libxl_bitmap_is_full(const libxl_bitmap *bitmap)
{
    int i;

    for (i = 0; i < bitmap->size; i++)
        if (bitmap->map[i] != (uint8_t)-1)
            return 0;
   return 1;
}

int libxl_bitmap_is_empty(const libxl_bitmap *bitmap)
{
    int i;

    for (i = 0; i < bitmap->size; i++)
        if (bitmap->map[i])
            return 0;
    return 1;
}

int libxl_bitmap_test(const libxl_bitmap *bitmap, int bit)
{
    if (bit >= bitmap->size * 8 || bit < 0)
        return 0;
    return (bitmap->map[bit / 8] & (1 << (bit & 7))) ? 1 : 0;
}

void libxl_bitmap_set(libxl_bitmap *bitmap, int bit)
{
    if (bit >= bitmap->size * 8 || bit < 0)
        return;
    bitmap->map[bit / 8] |= 1 << (bit & 7);
}

void libxl_bitmap_reset(libxl_bitmap *bitmap, int bit)
{
    if (bit >= bitmap->size * 8 || bit < 0)
        return;
    bitmap->map[bit / 8] &= ~(1 << (bit & 7));
}

int libxl_bitmap_or(libxl_ctx *ctx, libxl_bitmap *or_map,
                    const libxl_bitmap *map1, const libxl_bitmap *map2)
{
    GC_INIT(ctx);
    int rc;
    uint32_t i;
    const libxl_bitmap *large_map;
    const libxl_bitmap *small_map;

    if (map1->size > map2->size) {
        large_map = map1;
        small_map = map2;
    } else {
        large_map = map2;
        small_map = map1;
    }

    rc = libxl_bitmap_alloc(ctx, or_map, large_map->size * 8);
    if (rc)
        goto out;

    /*
     *  If bitmaps aren't the same size, their union (logical or) will
     *  be size of larger bit map.  Any bit past the end of the
     *  smaller bit map, will match the larger one.
     */
    for (i = 0; i < small_map->size; i++)
        or_map->map[i] = (small_map->map[i] | large_map->map[i]);

    for (i = small_map->size; i < large_map->size; i++)
        or_map->map[i] = large_map->map[i];

out:
    GC_FREE;
    return rc;
}

int libxl_bitmap_and(libxl_ctx *ctx, libxl_bitmap *and_map,
                     const libxl_bitmap *map1, const libxl_bitmap *map2)
{
    GC_INIT(ctx);
    int rc;
    uint32_t i;
    const libxl_bitmap *large_map;
    const libxl_bitmap *small_map;

    if (map1->size > map2->size) {
        large_map = map1;
        small_map = map2;
    } else {
        large_map = map2;
        small_map = map1;
    }

    rc = libxl_bitmap_alloc(ctx, and_map, small_map->size * 8);
    if (rc)
        goto out;

    /*
     *  If bitmaps aren't same size, their 'and' will be size of
     *  smaller bit map
     */
    for (i = 0; i < and_map->size; i++)
        and_map->map[i] = (large_map->map[i] & small_map->map[i]);

out:
    GC_FREE;
    return rc;
}

int libxl_bitmap_count_set(const libxl_bitmap *bitmap)
{
    int i, nr_set_bits = 0;
    libxl_for_each_set_bit(i, *bitmap)
        nr_set_bits++;

    return nr_set_bits;
}

/* NB. caller is responsible for freeing the memory */
char *libxl_bitmap_to_hex_string(libxl_ctx *ctx, const libxl_bitmap *bitmap)
{
    GC_INIT(ctx);
    int i = bitmap->size;
    char *p = libxl__zalloc(NOGC, bitmap->size * 2 + 3);
    char *q = p;
    strncpy(p, "0x", 3);
    p += 2;
    while(--i >= 0) {
        sprintf(p, "%02x", bitmap->map[i]);
        p += 2;
    }
    *p = '\0';
    GC_FREE;
    return q;
}

int libxl_cpu_bitmap_alloc(libxl_ctx *ctx, libxl_bitmap *cpumap, int max_cpus)
{
    GC_INIT(ctx);
    int rc = 0;

    if (max_cpus < 0) {
        rc = ERROR_INVAL;
        LOG(ERROR, "invalid number of cpus provided");
        goto out;
    }
    if (max_cpus == 0)
        max_cpus = libxl_get_max_cpus(ctx);
    if (max_cpus < 0) {
        LOG(ERROR, "failed to retrieve the maximum number of cpus");
        rc = max_cpus;
        goto out;
    }
    /* This can't fail: no need to check and log */
    libxl_bitmap_alloc(ctx, cpumap, max_cpus);

 out:
    GC_FREE;
    return rc;
}

int libxl_node_bitmap_alloc(libxl_ctx *ctx, libxl_bitmap *nodemap,
                            int max_nodes)
{
    GC_INIT(ctx);
    int rc = 0;

    if (max_nodes < 0) {
        rc = ERROR_INVAL;
        LOG(ERROR, "invalid number of nodes provided");
        goto out;
    }

    if (max_nodes == 0)
        max_nodes = libxl_get_max_nodes(ctx);
    if (max_nodes < 0) {
        LOG(ERROR, "failed to retrieve the maximum number of nodes");
        rc = max_nodes;
        goto out;
    }
    /* This can't fail: no need to check and log */
    libxl_bitmap_alloc(ctx, nodemap, max_nodes);

 out:
    GC_FREE;
    return rc;
}

int libxl__count_physical_sockets(libxl__gc *gc, int *sockets)
{
    int rc;
    libxl_physinfo info;

    libxl_physinfo_init(&info);

    rc = libxl_get_physinfo(CTX, &info);
    if (rc)
        return rc;

    *sockets = info.nr_cpus / info.threads_per_core
                            / info.cores_per_socket;

    libxl_physinfo_dispose(&info);
    return 0;
}

int libxl_socket_bitmap_alloc(libxl_ctx *ctx, libxl_bitmap *socketmap,
                              int max_sockets)
{
    GC_INIT(ctx);
    int rc = 0;

    if (max_sockets < 0) {
        rc = ERROR_INVAL;
        LOG(ERROR, "invalid number of sockets provided");
        goto out;
    }

    if (max_sockets == 0) {
        rc = libxl__count_physical_sockets(gc, &max_sockets);
        if (rc) {
            LOGE(ERROR, "failed to get system socket count");
            goto out;
        }
    }
    /* This can't fail: no need to check and log */
    libxl_bitmap_alloc(ctx, socketmap, max_sockets);

 out:
    GC_FREE;
    return rc;

}

int libxl_get_online_socketmap(libxl_ctx *ctx, libxl_bitmap *socketmap)
{
    libxl_cputopology *tinfo = NULL;
    int nr_cpus = 0, i, rc = 0;

    tinfo = libxl_get_cpu_topology(ctx, &nr_cpus);
    if (tinfo == NULL) {
        rc = ERROR_FAIL;
        goto out;
    }

    libxl_bitmap_set_none(socketmap);
    for (i = 0; i < nr_cpus; i++)
        if (tinfo[i].socket != XEN_INVALID_SOCKET_ID
            && !libxl_bitmap_test(socketmap, tinfo[i].socket))
            libxl_bitmap_set(socketmap, tinfo[i].socket);

 out:
    libxl_cputopology_list_free(tinfo, nr_cpus);
    return rc;
}

int libxl_nodemap_to_cpumap(libxl_ctx *ctx,
                            const libxl_bitmap *nodemap,
                            libxl_bitmap *cpumap)
{
    libxl_cputopology *tinfo = NULL;
    int nr_cpus = 0, i, rc = 0;

    tinfo = libxl_get_cpu_topology(ctx, &nr_cpus);
    if (tinfo == NULL) {
        rc = ERROR_FAIL;
        goto out;
    }

    libxl_bitmap_set_none(cpumap);
    for (i = 0; i < nr_cpus; i++) {
        if (libxl_bitmap_test(nodemap, tinfo[i].node))
            libxl_bitmap_set(cpumap, i);
    }
 out:
    libxl_cputopology_list_free(tinfo, nr_cpus);
    return rc;
}

int libxl_node_to_cpumap(libxl_ctx *ctx, int node,
                         libxl_bitmap *cpumap)
{
    libxl_bitmap nodemap;
    int rc = 0;

    libxl_bitmap_init(&nodemap);

    rc = libxl_node_bitmap_alloc(ctx, &nodemap, 0);
    if (rc)
        goto out;

    libxl_bitmap_set_none(&nodemap);
    libxl_bitmap_set(&nodemap, node);

    rc = libxl_nodemap_to_cpumap(ctx, &nodemap, cpumap);

 out:
    libxl_bitmap_dispose(&nodemap);
    return rc;
}

int libxl_cpumap_to_nodemap(libxl_ctx *ctx,
                            const libxl_bitmap *cpumap,
                            libxl_bitmap *nodemap)
{
    libxl_cputopology *tinfo = NULL;
    int nr_cpus = 0, i, rc = 0;

    tinfo = libxl_get_cpu_topology(ctx, &nr_cpus);
    if (tinfo == NULL) {
        rc = ERROR_FAIL;
        goto out;
    }

    libxl_bitmap_set_none(nodemap);
    libxl_for_each_set_bit(i, *cpumap) {
        if (i >= nr_cpus)
            break;
        libxl_bitmap_set(nodemap, tinfo[i].node);
    }
 out:
    libxl_cputopology_list_free(tinfo, nr_cpus);
    return rc;
}

int libxl_get_max_cpus(libxl_ctx *ctx)
{
    int max_cpus = xc_get_max_cpus(ctx->xch);

    return max_cpus < 0 ? ERROR_FAIL : max_cpus;
}

int libxl_get_online_cpus(libxl_ctx *ctx)
{
    int online_cpus = xc_get_online_cpus(ctx->xch);

    return online_cpus < 0 ? ERROR_FAIL : online_cpus;
}

int libxl_get_max_nodes(libxl_ctx *ctx)
{
    int max_nodes = xc_get_max_nodes(ctx->xch);

    return max_nodes < 0 ? ERROR_FAIL : max_nodes;
}

int libxl__enum_from_string(const libxl_enum_string_table *t,
                            const char *s, int *e)
{
    if (!t) return ERROR_INVAL;

    for( ; t->s; t++) {
        if (!strcasecmp(t->s, s)) {
                *e = t->v;
                return 0;
        }
    }
    return ERROR_FAIL;
}

void libxl_cputopology_list_free(libxl_cputopology *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_cputopology_dispose(&list[i]);
    free(list);
}

void libxl_pcitopology_list_free(libxl_pcitopology *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_pcitopology_dispose(&list[i]);
    free(list);
}

void libxl_numainfo_list_free(libxl_numainfo *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_numainfo_dispose(&list[i]);
    free(list);
}

void libxl_vcpuinfo_list_free(libxl_vcpuinfo *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_vcpuinfo_dispose(&list[i]);
    free(list);
}

int libxl__sendmsg_fds(libxl__gc *gc, int carrier,
                       const char data,
                       int nfds, const int fds[], const char *what) {
    struct msghdr msg = { 0 };
    struct cmsghdr *cmsg;
    size_t spaceneeded = nfds * sizeof(fds[0]);
    char control[CMSG_SPACE(spaceneeded)];
    const size_t datalen = 1;
    struct iovec iov;
    int r;

    iov.iov_base = (void*)&data;
    iov.iov_len  = datalen;

    /* compose the message */
    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;
    msg.msg_control = control;
    msg.msg_controllen = sizeof(control);

    /* attach open fd */
    cmsg = CMSG_FIRSTHDR(&msg);
    cmsg->cmsg_level = SOL_SOCKET;
    cmsg->cmsg_type = SCM_RIGHTS;
    cmsg->cmsg_len = CMSG_LEN(spaceneeded);
    memcpy(CMSG_DATA(cmsg), fds, spaceneeded);

    msg.msg_controllen = cmsg->cmsg_len;

    while (1) {
        r = sendmsg(carrier, &msg, 0);
        if (r < 0) {
            if (errno == EINTR)
                continue;
            if (errno == EWOULDBLOCK) {
                return ERROR_NOT_READY;
            }
            LOGE(ERROR, "failed to send fd-carrying message (%s)", what);
            return ERROR_FAIL;
        }
        if (r != datalen) {
            LOG(ERROR, "sendmsg have written %d instead of %zu",
                r, datalen);
            return ERROR_FAIL;
        }
        break;
    };

    return 0;
}

int libxl__recvmsg_fds(libxl__gc *gc, int carrier,
                       void *databuf, size_t datalen,
                       int nfds, int fds[], const char *what)
{
    struct msghdr msg = { 0 };
    struct cmsghdr *cmsg;
    size_t spaceneeded = nfds * sizeof(fds[0]);
    char control[CMSG_SPACE(spaceneeded)];
    struct iovec iov;
    int r;

    iov.iov_base = databuf;
    iov.iov_len  = datalen;

    msg.msg_iov = &iov;
    msg.msg_iovlen = 1;
    msg.msg_control = control;
    msg.msg_controllen = sizeof(control);

    for (;;) {
        r = recvmsg(carrier, &msg, 0);
        if (r < 0) {
            if (errno == EINTR) continue;
            if (errno == EWOULDBLOCK) return -1;
            LOGE(ERROR,"recvmsg failed (%s)", what);
            return ERROR_FAIL;
        }
        if (r == 0) {
            LOG(ERROR,"recvmsg got EOF (%s)", what);
            return ERROR_FAIL;
        }
        cmsg = CMSG_FIRSTHDR(&msg);
        if (cmsg->cmsg_len <= CMSG_LEN(0)) {
            LOG(ERROR,"recvmsg got no control msg"
                " when expecting fds (%s)", what);
            return ERROR_FAIL;
        }
        if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
            LOG(ERROR, "recvmsg got unexpected"
                " cmsg_level %d (!=%d) or _type %d (!=%d) (%s)",
                cmsg->cmsg_level, SOL_SOCKET,
                cmsg->cmsg_type, SCM_RIGHTS,
                what);
            return ERROR_FAIL;
        }
        if (cmsg->cmsg_len != CMSG_LEN(spaceneeded) ||
            msg.msg_controllen != cmsg->cmsg_len) {
            LOG(ERROR, "recvmsg got unexpected"
                " number of fds or extra control data"
                " (%ld bytes' worth, expected %ld) (%s)",
                (long)CMSG_LEN(spaceneeded), (long)cmsg->cmsg_len,
                what);
            int i, fd;
            unsigned char *p;
            for (i=0, p=CMSG_DATA(cmsg);
                 CMSG_SPACE(i * sizeof(fds[0]));
                 i++, i+=sizeof(fd)) {
                memcpy(&fd, p, sizeof(fd));
                close(fd);
            }
            return ERROR_FAIL;
        }
        memcpy(fds, CMSG_DATA(cmsg), spaceneeded);
        return 0;
    }
}

void libxl_dominfo_list_free(libxl_dominfo *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_dominfo_dispose(&list[i]);
    free(list);
}

void libxl_vminfo_list_free(libxl_vminfo *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_vminfo_dispose(&list[i]);
    free(list);
}

void libxl_cpupoolinfo_list_free(libxl_cpupoolinfo *list, int nr)
{
    int i;
    for (i = 0; i < nr; i++)
        libxl_cpupoolinfo_dispose(&list[i]);
    free(list);
}

int libxl_domid_valid_guest(uint32_t domid)
{
    /* returns 1 if the value _could_ be a valid guest domid, 0 otherwise
     * does not check whether the domain actually exists */
    return domid > 0 && domid < DOMID_FIRST_RESERVED;
}

void libxl_string_copy(libxl_ctx *ctx, char **dst, char * const*src)
{
    GC_INIT(ctx);

    if (*src)
        *dst = libxl__strdup(NOGC, *src);
    else
        *dst = NULL;

    GC_FREE;
}

/*
 * Fill @buf with @len random bytes.
 */
int libxl__random_bytes(libxl__gc *gc, uint8_t *buf, size_t len)
{
    static const char *dev = "/dev/urandom";
    int fd;
    int ret;

    fd = open(dev, O_RDONLY);
    if (fd < 0) {
        LOGE(ERROR, "failed to open \"%s\"", dev);
        return ERROR_FAIL;
    }
    ret = libxl_fd_set_cloexec(CTX, fd, 1);
    if (ret) {
        close(fd);
        return ERROR_FAIL;
    }

    ret = libxl_read_exactly(CTX, fd, buf, len, dev, NULL);

    close(fd);

    return ret;
}

int libxl__prepare_sockaddr_un(libxl__gc *gc,
                               struct sockaddr_un *un, const char *path,
                               const char *what)
{
    if (sizeof(un->sun_path) - 1 <= strlen(path)) {
        LOG(ERROR, "UNIX socket path '%s' is too long for %s", path, what);
        LOG(DEBUG, "Path must be less than %zu bytes", sizeof(un->sun_path) - 1);
        return ERROR_INVAL;
    }
    memset(un, 0, sizeof(struct sockaddr_un));
    un->sun_family = AF_UNIX;
    strncpy(un->sun_path, path, sizeof(un->sun_path) - 1);
    return 0;
}

/*
 * Local variables:
 * mode: C
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 */