[mirror_ubuntu-artful-kernel.git] / tools / perf / util / dso.c

#include <asm/bug.h>
#include <sys/time.h>
#include <sys/resource.h>
#include "symbol.h"
#include "dso.h"
#include "machine.h"
#include "auxtrace.h"
#include "util.h"
#include "debug.h"

char dso__symtab_origin(const struct dso *dso)
{
        static const char origin[] = {
                [DSO_BINARY_TYPE__KALLSYMS]                     = 'k',
                [DSO_BINARY_TYPE__VMLINUX]                      = 'v',
                [DSO_BINARY_TYPE__JAVA_JIT]                     = 'j',
                [DSO_BINARY_TYPE__DEBUGLINK]                    = 'l',
                [DSO_BINARY_TYPE__BUILD_ID_CACHE]               = 'B',
                [DSO_BINARY_TYPE__FEDORA_DEBUGINFO]             = 'f',
                [DSO_BINARY_TYPE__UBUNTU_DEBUGINFO]             = 'u',
                [DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO]       = 'o',
                [DSO_BINARY_TYPE__BUILDID_DEBUGINFO]            = 'b',
                [DSO_BINARY_TYPE__SYSTEM_PATH_DSO]              = 'd',
                [DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE]          = 'K',
                [DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP]     = 'm',
                [DSO_BINARY_TYPE__GUEST_KALLSYMS]               = 'g',
                [DSO_BINARY_TYPE__GUEST_KMODULE]                = 'G',
                [DSO_BINARY_TYPE__GUEST_KMODULE_COMP]           = 'M',
                [DSO_BINARY_TYPE__GUEST_VMLINUX]                = 'V',
        };

        if (dso == NULL || dso->symtab_type == DSO_BINARY_TYPE__NOT_FOUND)
                return '!';
        return origin[dso->symtab_type];
}

int dso__read_binary_type_filename(const struct dso *dso,
                                   enum dso_binary_type type,
                                   char *root_dir, char *filename, size_t size)
{
        char build_id_hex[BUILD_ID_SIZE * 2 + 1];
        int ret = 0;
        size_t len;

        switch (type) {
        case DSO_BINARY_TYPE__DEBUGLINK: {
                char *debuglink;

                len = __symbol__join_symfs(filename, size, dso->long_name);
                debuglink = filename + len;
                while (debuglink != filename && *debuglink != '/')
                        debuglink--;
                if (*debuglink == '/')
                        debuglink++;

                ret = -1;
                if (!is_regular_file(filename))
                        break;

                ret = filename__read_debuglink(filename, debuglink,
                                               size - (debuglink - filename));
                }
                break;
        case DSO_BINARY_TYPE__BUILD_ID_CACHE:
                /* skip the locally configured cache if a symfs is given */
                if (symbol_conf.symfs[0] ||
                    (dso__build_id_filename(dso, filename, size) == NULL))
                        ret = -1;
                break;

        case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
                len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
                snprintf(filename + len, size - len, "%s.debug", dso->long_name);
                break;

        case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
                len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
                snprintf(filename + len, size - len, "%s", dso->long_name);
                break;

        case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
        {
                const char *last_slash;
                size_t dir_size;

                last_slash = dso->long_name + dso->long_name_len;
                while (last_slash != dso->long_name && *last_slash != '/')
                        last_slash--;

                len = __symbol__join_symfs(filename, size, "");
                dir_size = last_slash - dso->long_name + 2;
                if (dir_size > (size - len)) {
                        ret = -1;
                        break;
                }
                len += scnprintf(filename + len, dir_size, "%s",  dso->long_name);
                len += scnprintf(filename + len , size - len, ".debug%s",
                                                                last_slash);
                break;
        }

        case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
                if (!dso->has_build_id) {
                        ret = -1;
                        break;
                }

                build_id__sprintf(dso->build_id,
                                  sizeof(dso->build_id),
                                  build_id_hex);
                len = __symbol__join_symfs(filename, size, "/usr/lib/debug/.build-id/");
                snprintf(filename + len, size - len, "%.2s/%s.debug",
                         build_id_hex, build_id_hex + 2);
                break;

        case DSO_BINARY_TYPE__VMLINUX:
        case DSO_BINARY_TYPE__GUEST_VMLINUX:
        case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
                __symbol__join_symfs(filename, size, dso->long_name);
                break;

        case DSO_BINARY_TYPE__GUEST_KMODULE:
        case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
                path__join3(filename, size, symbol_conf.symfs,
                            root_dir, dso->long_name);
                break;

        case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
        case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
                __symbol__join_symfs(filename, size, dso->long_name);
                break;

        case DSO_BINARY_TYPE__KCORE:
        case DSO_BINARY_TYPE__GUEST_KCORE:
                snprintf(filename, size, "%s", dso->long_name);
                break;

        default:
        case DSO_BINARY_TYPE__KALLSYMS:
        case DSO_BINARY_TYPE__GUEST_KALLSYMS:
        case DSO_BINARY_TYPE__JAVA_JIT:
        case DSO_BINARY_TYPE__NOT_FOUND:
                ret = -1;
                break;
        }

        return ret;
}

static const struct {
        const char *fmt;
        int (*decompress)(const char *input, int output);
} compressions[] = {
#ifdef HAVE_ZLIB_SUPPORT
        { "gz", gzip_decompress_to_file },
#endif
#ifdef HAVE_LZMA_SUPPORT
        { "xz", lzma_decompress_to_file },
#endif
        { NULL, NULL },
};

bool is_supported_compression(const char *ext)
{
        unsigned i;

        for (i = 0; compressions[i].fmt; i++) {
                if (!strcmp(ext, compressions[i].fmt))
                        return true;
        }
        return false;
}

bool is_kernel_module(const char *pathname, int cpumode)
{
        struct kmod_path m;
        int mode = cpumode & PERF_RECORD_MISC_CPUMODE_MASK;

        WARN_ONCE(mode != cpumode,
                  "Internal error: passing unmasked cpumode (%x) to is_kernel_module",
                  cpumode);

        switch (mode) {
        case PERF_RECORD_MISC_USER:
        case PERF_RECORD_MISC_HYPERVISOR:
        case PERF_RECORD_MISC_GUEST_USER:
                return false;
        /* Treat PERF_RECORD_MISC_CPUMODE_UNKNOWN as kernel */
        default:
                if (kmod_path__parse(&m, pathname)) {
                        pr_err("Failed to check whether %s is a kernel module or not. Assume it is.",
                                        pathname);
                        return true;
                }
        }

        return m.kmod;
}

bool decompress_to_file(const char *ext, const char *filename, int output_fd)
{
        unsigned i;

        for (i = 0; compressions[i].fmt; i++) {
                if (!strcmp(ext, compressions[i].fmt))
                        return !compressions[i].decompress(filename,
                                                           output_fd);
        }
        return false;
}

bool dso__needs_decompress(struct dso *dso)
{
        return dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP ||
                dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;
}

/*
 * Parses kernel module specified in @path and updates
 * @m argument like:
 *
 *    @comp - true if @path contains supported compression suffix,
 *            false otherwise
 *    @kmod - true if @path contains '.ko' suffix in right position,
 *            false otherwise
 *    @name - if (@alloc_name && @kmod) is true, it contains strdup-ed base name
 *            of the kernel module without suffixes, otherwise strudup-ed
 *            base name of @path
 *    @ext  - if (@alloc_ext && @comp) is true, it contains strdup-ed string
 *            the compression suffix
 *
 * Returns 0 if there's no strdup error, -ENOMEM otherwise.
 */
int __kmod_path__parse(struct kmod_path *m, const char *path,
                       bool alloc_name, bool alloc_ext)
{
        const char *name = strrchr(path, '/');
        const char *ext  = strrchr(path, '.');
        bool is_simple_name = false;

        memset(m, 0x0, sizeof(*m));
        name = name ? name + 1 : path;

        /*
         * '.' is also a valid character for module name. For example:
         * [aaa.bbb] is a valid module name. '[' should have higher
         * priority than '.ko' suffix.
         *
         * The kernel names are from machine__mmap_name. Such
         * name should belong to kernel itself, not kernel module.
         */
        if (name[0] == '[') {
                is_simple_name = true;
                if ((strncmp(name, "[kernel.kallsyms]", 17) == 0) ||
                    (strncmp(name, "[guest.kernel.kallsyms", 22) == 0) ||
                    (strncmp(name, "[vdso]", 6) == 0) ||
                    (strncmp(name, "[vsyscall]", 10) == 0)) {
                        m->kmod = false;

                } else
                        m->kmod = true;
        }

        /* No extension, just return name. */
        if ((ext == NULL) || is_simple_name) {
                if (alloc_name) {
                        m->name = strdup(name);
                        return m->name ? 0 : -ENOMEM;
                }
                return 0;
        }

        if (is_supported_compression(ext + 1)) {
                m->comp = true;
                ext -= 3;
        }

        /* Check .ko extension only if there's enough name left. */
        if (ext > name)
                m->kmod = !strncmp(ext, ".ko", 3);

        if (alloc_name) {
                if (m->kmod) {
                        if (asprintf(&m->name, "[%.*s]", (int) (ext - name), name) == -1)
                                return -ENOMEM;
                } else {
                        if (asprintf(&m->name, "%s", name) == -1)
                                return -ENOMEM;
                }

                strxfrchar(m->name, '-', '_');
        }

        if (alloc_ext && m->comp) {
                m->ext = strdup(ext + 4);
                if (!m->ext) {
                        free((void *) m->name);
                        return -ENOMEM;
                }
        }

        return 0;
}

/*
 * Global list of open DSOs and the counter.
 */
static LIST_HEAD(dso__data_open);
static long dso__data_open_cnt;
static pthread_mutex_t dso__data_open_lock = PTHREAD_MUTEX_INITIALIZER;

static void dso__list_add(struct dso *dso)
{
        list_add_tail(&dso->data.open_entry, &dso__data_open);
        dso__data_open_cnt++;
}

static void dso__list_del(struct dso *dso)
{
        list_del(&dso->data.open_entry);
        WARN_ONCE(dso__data_open_cnt <= 0,
                  "DSO data fd counter out of bounds.");
        dso__data_open_cnt--;
}

static void close_first_dso(void);

static int do_open(char *name)
{
        int fd;
        char sbuf[STRERR_BUFSIZE];

        do {
                fd = open(name, O_RDONLY);
                if (fd >= 0)
                        return fd;

                pr_debug("dso open failed: %s\n",
                         strerror_r(errno, sbuf, sizeof(sbuf)));
                if (!dso__data_open_cnt || errno != EMFILE)
                        break;

                close_first_dso();
        } while (1);

        return -1;
}

static int __open_dso(struct dso *dso, struct machine *machine)
{
        int fd;
        char *root_dir = (char *)"";
        char *name = malloc(PATH_MAX);

        if (!name)
                return -ENOMEM;

        if (machine)
                root_dir = machine->root_dir;

        if (dso__read_binary_type_filename(dso, dso->binary_type,
                                            root_dir, name, PATH_MAX)) {
                free(name);
                return -EINVAL;
        }

        fd = do_open(name);
        free(name);
        return fd;
}

static void check_data_close(void);

/**
 * dso_close - Open DSO data file
 * @dso: dso object
 *
 * Open @dso's data file descriptor and updates
 * list/count of open DSO objects.
 */
static int open_dso(struct dso *dso, struct machine *machine)
{
        int fd = __open_dso(dso, machine);

        if (fd >= 0) {
                dso__list_add(dso);
                /*
                 * Check if we crossed the allowed number
                 * of opened DSOs and close one if needed.
                 */
                check_data_close();
        }

        return fd;
}

static void close_data_fd(struct dso *dso)
{
        if (dso->data.fd >= 0) {
                close(dso->data.fd);
                dso->data.fd = -1;
                dso->data.file_size = 0;
                dso__list_del(dso);
        }
}

/**
 * dso_close - Close DSO data file
 * @dso: dso object
 *
 * Close @dso's data file descriptor and updates
 * list/count of open DSO objects.
 */
static void close_dso(struct dso *dso)
{
        close_data_fd(dso);
}

static void close_first_dso(void)
{
        struct dso *dso;

        dso = list_first_entry(&dso__data_open, struct dso, data.open_entry);
        close_dso(dso);
}

static rlim_t get_fd_limit(void)
{
        struct rlimit l;
        rlim_t limit = 0;

        /* Allow half of the current open fd limit. */
        if (getrlimit(RLIMIT_NOFILE, &l) == 0) {
                if (l.rlim_cur == RLIM_INFINITY)
                        limit = l.rlim_cur;
                else
                        limit = l.rlim_cur / 2;
        } else {
                pr_err("failed to get fd limit\n");
                limit = 1;
        }

        return limit;
}

static bool may_cache_fd(void)
{
        static rlim_t limit;

        if (!limit)
                limit = get_fd_limit();

        if (limit == RLIM_INFINITY)
                return true;

        return limit > (rlim_t) dso__data_open_cnt;
}

/*
 * Check and close LRU dso if we crossed allowed limit
 * for opened dso file descriptors. The limit is half
 * of the RLIMIT_NOFILE files opened.
*/
static void check_data_close(void)
{
        bool cache_fd = may_cache_fd();

        if (!cache_fd)
                close_first_dso();
}

/**
 * dso__data_close - Close DSO data file
 * @dso: dso object
 *
 * External interface to close @dso's data file descriptor.
 */
void dso__data_close(struct dso *dso)
{
        pthread_mutex_lock(&dso__data_open_lock);
        close_dso(dso);
        pthread_mutex_unlock(&dso__data_open_lock);
}

static void try_to_open_dso(struct dso *dso, struct machine *machine)
{
        enum dso_binary_type binary_type_data[] = {
                DSO_BINARY_TYPE__BUILD_ID_CACHE,
                DSO_BINARY_TYPE__SYSTEM_PATH_DSO,
                DSO_BINARY_TYPE__NOT_FOUND,
        };
        int i = 0;

        if (dso->data.fd >= 0)
                return;

        if (dso->binary_type != DSO_BINARY_TYPE__NOT_FOUND) {
                dso->data.fd = open_dso(dso, machine);
                goto out;
        }

        do {
                dso->binary_type = binary_type_data[i++];

                dso->data.fd = open_dso(dso, machine);
                if (dso->data.fd >= 0)
                        goto out;

        } while (dso->binary_type != DSO_BINARY_TYPE__NOT_FOUND);
out:
        if (dso->data.fd >= 0)
                dso->data.status = DSO_DATA_STATUS_OK;
        else
                dso->data.status = DSO_DATA_STATUS_ERROR;
}

/**
 * dso__data_get_fd - Get dso's data file descriptor
 * @dso: dso object
 * @machine: machine object
 *
 * External interface to find dso's file, open it and
 * returns file descriptor.  It should be paired with
 * dso__data_put_fd() if it returns non-negative value.
 */
int dso__data_get_fd(struct dso *dso, struct machine *machine)
{
        if (dso->data.status == DSO_DATA_STATUS_ERROR)
                return -1;

        if (pthread_mutex_lock(&dso__data_open_lock) < 0)
                return -1;

        try_to_open_dso(dso, machine);

        if (dso->data.fd < 0)
                pthread_mutex_unlock(&dso__data_open_lock);

        return dso->data.fd;
}

void dso__data_put_fd(struct dso *dso __maybe_unused)
{
        pthread_mutex_unlock(&dso__data_open_lock);
}

bool dso__data_status_seen(struct dso *dso, enum dso_data_status_seen by)
{
        u32 flag = 1 << by;

        if (dso->data.status_seen & flag)
                return true;

        dso->data.status_seen |= flag;

        return false;
}

static void
dso_cache__free(struct dso *dso)
{
        struct rb_root *root = &dso->data.cache;
        struct rb_node *next = rb_first(root);

        pthread_mutex_lock(&dso->lock);
        while (next) {
                struct dso_cache *cache;

                cache = rb_entry(next, struct dso_cache, rb_node);
                next = rb_next(&cache->rb_node);
                rb_erase(&cache->rb_node, root);
                free(cache);
        }
        pthread_mutex_unlock(&dso->lock);
}

static struct dso_cache *dso_cache__find(struct dso *dso, u64 offset)
{
        const struct rb_root *root = &dso->data.cache;
        struct rb_node * const *p = &root->rb_node;
        const struct rb_node *parent = NULL;
        struct dso_cache *cache;

        while (*p != NULL) {
                u64 end;

                parent = *p;
                cache = rb_entry(parent, struct dso_cache, rb_node);
                end = cache->offset + DSO__DATA_CACHE_SIZE;

                if (offset < cache->offset)
                        p = &(*p)->rb_left;
                else if (offset >= end)
                        p = &(*p)->rb_right;
                else
                        return cache;
        }

        return NULL;
}

static struct dso_cache *
dso_cache__insert(struct dso *dso, struct dso_cache *new)
{
        struct rb_root *root = &dso->data.cache;
        struct rb_node **p = &root->rb_node;
        struct rb_node *parent = NULL;
        struct dso_cache *cache;
        u64 offset = new->offset;

        pthread_mutex_lock(&dso->lock);
        while (*p != NULL) {
                u64 end;

                parent = *p;
                cache = rb_entry(parent, struct dso_cache, rb_node);
                end = cache->offset + DSO__DATA_CACHE_SIZE;

                if (offset < cache->offset)
                        p = &(*p)->rb_left;
                else if (offset >= end)
                        p = &(*p)->rb_right;
                else
                        goto out;
        }

        rb_link_node(&new->rb_node, parent, p);
        rb_insert_color(&new->rb_node, root);

        cache = NULL;
out:
        pthread_mutex_unlock(&dso->lock);
        return cache;
}

static ssize_t
dso_cache__memcpy(struct dso_cache *cache, u64 offset,
                  u8 *data, u64 size)
{
        u64 cache_offset = offset - cache->offset;
        u64 cache_size   = min(cache->size - cache_offset, size);

        memcpy(data, cache->data + cache_offset, cache_size);
        return cache_size;
}

static ssize_t
dso_cache__read(struct dso *dso, struct machine *machine,
                u64 offset, u8 *data, ssize_t size)
{
        struct dso_cache *cache;
        struct dso_cache *old;
        ssize_t ret;

        do {
                u64 cache_offset;

                cache = zalloc(sizeof(*cache) + DSO__DATA_CACHE_SIZE);
                if (!cache)
                        return -ENOMEM;

                pthread_mutex_lock(&dso__data_open_lock);

                /*
                 * dso->data.fd might be closed if other thread opened another
                 * file (dso) due to open file limit (RLIMIT_NOFILE).
                 */
                try_to_open_dso(dso, machine);

                if (dso->data.fd < 0) {
                        ret = -errno;
                        dso->data.status = DSO_DATA_STATUS_ERROR;
                        break;
                }

                cache_offset = offset & DSO__DATA_CACHE_MASK;

                ret = pread(dso->data.fd, cache->data, DSO__DATA_CACHE_SIZE, cache_offset);
                if (ret <= 0)
                        break;

                cache->offset = cache_offset;
                cache->size   = ret;
        } while (0);

        pthread_mutex_unlock(&dso__data_open_lock);

        if (ret > 0) {
                old = dso_cache__insert(dso, cache);
                if (old) {
                        /* we lose the race */
                        free(cache);
                        cache = old;
                }

                ret = dso_cache__memcpy(cache, offset, data, size);
        }

        if (ret <= 0)
                free(cache);

        return ret;
}

static ssize_t dso_cache_read(struct dso *dso, struct machine *machine,
                              u64 offset, u8 *data, ssize_t size)
{
        struct dso_cache *cache;

        cache = dso_cache__find(dso, offset);
        if (cache)
                return dso_cache__memcpy(cache, offset, data, size);
        else
                return dso_cache__read(dso, machine, offset, data, size);
}

/*
 * Reads and caches dso data DSO__DATA_CACHE_SIZE size chunks
 * in the rb_tree. Any read to already cached data is served
 * by cached data.
 */
static ssize_t cached_read(struct dso *dso, struct machine *machine,
                           u64 offset, u8 *data, ssize_t size)
{
        ssize_t r = 0;
        u8 *p = data;

        do {
                ssize_t ret;

                ret = dso_cache_read(dso, machine, offset, p, size);
                if (ret < 0)
                        return ret;

                /* Reached EOF, return what we have. */
                if (!ret)
                        break;

                BUG_ON(ret > size);

                r      += ret;
                p      += ret;
                offset += ret;
                size   -= ret;

        } while (size);

        return r;
}

static int data_file_size(struct dso *dso, struct machine *machine)
{
        int ret = 0;
        struct stat st;
        char sbuf[STRERR_BUFSIZE];

        if (dso->data.file_size)
                return 0;

        if (dso->data.status == DSO_DATA_STATUS_ERROR)
                return -1;

        pthread_mutex_lock(&dso__data_open_lock);

        /*
         * dso->data.fd might be closed if other thread opened another
         * file (dso) due to open file limit (RLIMIT_NOFILE).
         */
        try_to_open_dso(dso, machine);

        if (dso->data.fd < 0) {
                ret = -errno;
                dso->data.status = DSO_DATA_STATUS_ERROR;
                goto out;
        }

        if (fstat(dso->data.fd, &st) < 0) {
                ret = -errno;
                pr_err("dso cache fstat failed: %s\n",
                       strerror_r(errno, sbuf, sizeof(sbuf)));
                dso->data.status = DSO_DATA_STATUS_ERROR;
                goto out;
        }
        dso->data.file_size = st.st_size;

out:
        pthread_mutex_unlock(&dso__data_open_lock);
        return ret;
}

/**
 * dso__data_size - Return dso data size
 * @dso: dso object
 * @machine: machine object
 *
 * Return: dso data size
 */
off_t dso__data_size(struct dso *dso, struct machine *machine)
{
        if (data_file_size(dso, machine))
                return -1;

        /* For now just estimate dso data size is close to file size */
        return dso->data.file_size;
}

static ssize_t data_read_offset(struct dso *dso, struct machine *machine,
                                u64 offset, u8 *data, ssize_t size)
{
        if (data_file_size(dso, machine))
                return -1;

        /* Check the offset sanity. */
        if (offset > dso->data.file_size)
                return -1;

        if (offset + size < offset)
                return -1;

        return cached_read(dso, machine, offset, data, size);
}

/**
 * dso__data_read_offset - Read data from dso file offset
 * @dso: dso object
 * @machine: machine object
 * @offset: file offset
 * @data: buffer to store data
 * @size: size of the @data buffer
 *
 * External interface to read data from dso file offset. Open
 * dso data file and use cached_read to get the data.
 */
ssize_t dso__data_read_offset(struct dso *dso, struct machine *machine,
                              u64 offset, u8 *data, ssize_t size)
{
        if (dso->data.status == DSO_DATA_STATUS_ERROR)
                return -1;

        return data_read_offset(dso, machine, offset, data, size);
}

/**
 * dso__data_read_addr - Read data from dso address
 * @dso: dso object
 * @machine: machine object
 * @add: virtual memory address
 * @data: buffer to store data
 * @size: size of the @data buffer
 *
 * External interface to read data from dso address.
 */
ssize_t dso__data_read_addr(struct dso *dso, struct map *map,
                            struct machine *machine, u64 addr,
                            u8 *data, ssize_t size)
{
        u64 offset = map->map_ip(map, addr);
        return dso__data_read_offset(dso, machine, offset, data, size);
}

struct map *dso__new_map(const char *name)
{
        struct map *map = NULL;
        struct dso *dso = dso__new(name);

        if (dso)
                map = map__new2(0, dso, MAP__FUNCTION);

        return map;
}

struct dso *machine__findnew_kernel(struct machine *machine, const char *name,
                                    const char *short_name, int dso_type)
{
        /*
         * The kernel dso could be created by build_id processing.
         */
        struct dso *dso = machine__findnew_dso(machine, name);

        /*
         * We need to run this in all cases, since during the build_id
         * processing we had no idea this was the kernel dso.
         */
        if (dso != NULL) {
                dso__set_short_name(dso, short_name, false);
                dso->kernel = dso_type;
        }

        return dso;
}

/*
 * Find a matching entry and/or link current entry to RB tree.
 * Either one of the dso or name parameter must be non-NULL or the
 * function will not work.
 */
static struct dso *__dso__findlink_by_longname(struct rb_root *root,
                                               struct dso *dso, const char *name)
{
        struct rb_node **p = &root->rb_node;
        struct rb_node  *parent = NULL;

        if (!name)
                name = dso->long_name;
        /*
         * Find node with the matching name
         */
        while (*p) {
                struct dso *this = rb_entry(*p, struct dso, rb_node);
                int rc = strcmp(name, this->long_name);

                parent = *p;
                if (rc == 0) {
                        /*
                         * In case the new DSO is a duplicate of an existing
                         * one, print an one-time warning & put the new entry
                         * at the end of the list of duplicates.
                         */
                        if (!dso || (dso == this))
                                return this;    /* Find matching dso */
                        /*
                         * The core kernel DSOs may have duplicated long name.
                         * In this case, the short name should be different.
                         * Comparing the short names to differentiate the DSOs.
                         */
                        rc = strcmp(dso->short_name, this->short_name);
                        if (rc == 0) {
                                pr_err("Duplicated dso name: %s\n", name);
                                return NULL;
                        }
                }
                if (rc < 0)
                        p = &parent->rb_left;
                else
                        p = &parent->rb_right;
        }
        if (dso) {
                /* Add new node and rebalance tree */
                rb_link_node(&dso->rb_node, parent, p);
                rb_insert_color(&dso->rb_node, root);
                dso->root = root;
        }
        return NULL;
}

static inline struct dso *__dso__find_by_longname(struct rb_root *root,
                                                  const char *name)
{
        return __dso__findlink_by_longname(root, NULL, name);
}

void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
{
        struct rb_root *root = dso->root;

        if (name == NULL)
                return;

        if (dso->long_name_allocated)
                free((char *)dso->long_name);

        if (root) {
                rb_erase(&dso->rb_node, root);
                /*
                 * __dso__findlink_by_longname() isn't guaranteed to add it
                 * back, so a clean removal is required here.
                 */
                RB_CLEAR_NODE(&dso->rb_node);
                dso->root = NULL;
        }

        dso->long_name           = name;
        dso->long_name_len       = strlen(name);
        dso->long_name_allocated = name_allocated;

        if (root)
                __dso__findlink_by_longname(root, dso, NULL);
}

void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
{
        if (name == NULL)
                return;

        if (dso->short_name_allocated)
                free((char *)dso->short_name);

        dso->short_name           = name;
        dso->short_name_len       = strlen(name);
        dso->short_name_allocated = name_allocated;
}

static void dso__set_basename(struct dso *dso)
{
       /*
        * basename() may modify path buffer, so we must pass
        * a copy.
        */
       char *base, *lname = strdup(dso->long_name);

       if (!lname)
               return;

       /*
        * basename() may return a pointer to internal
        * storage which is reused in subsequent calls
        * so copy the result.
        */
       base = strdup(basename(lname));

       free(lname);

       if (!base)
               return;

       dso__set_short_name(dso, base, true);
}

int dso__name_len(const struct dso *dso)
{
        if (!dso)
                return strlen("[unknown]");
        if (verbose)
                return dso->long_name_len;

        return dso->short_name_len;
}

bool dso__loaded(const struct dso *dso, enum map_type type)
{
        return dso->loaded & (1 << type);
}

bool dso__sorted_by_name(const struct dso *dso, enum map_type type)
{
        return dso->sorted_by_name & (1 << type);
}

void dso__set_sorted_by_name(struct dso *dso, enum map_type type)
{
        dso->sorted_by_name |= (1 << type);
}

struct dso *dso__new(const char *name)
{
        struct dso *dso = calloc(1, sizeof(*dso) + strlen(name) + 1);

        if (dso != NULL) {
                int i;
                strcpy(dso->name, name);
                dso__set_long_name(dso, dso->name, false);
                dso__set_short_name(dso, dso->name, false);
                for (i = 0; i < MAP__NR_TYPES; ++i)
                        dso->symbols[i] = dso->symbol_names[i] = RB_ROOT;
                dso->data.cache = RB_ROOT;
                dso->data.fd = -1;
                dso->data.status = DSO_DATA_STATUS_UNKNOWN;
                dso->symtab_type = DSO_BINARY_TYPE__NOT_FOUND;
                dso->binary_type = DSO_BINARY_TYPE__NOT_FOUND;
                dso->is_64_bit = (sizeof(void *) == 8);
                dso->loaded = 0;
                dso->rel = 0;
                dso->sorted_by_name = 0;
                dso->has_build_id = 0;
                dso->has_srcline = 1;
                dso->a2l_fails = 1;
                dso->kernel = DSO_TYPE_USER;
                dso->needs_swap = DSO_SWAP__UNSET;
                RB_CLEAR_NODE(&dso->rb_node);
                dso->root = NULL;
                INIT_LIST_HEAD(&dso->node);
                INIT_LIST_HEAD(&dso->data.open_entry);
                pthread_mutex_init(&dso->lock, NULL);
                atomic_set(&dso->refcnt, 1);
        }

        return dso;
}

void dso__delete(struct dso *dso)
{
        int i;

        if (!RB_EMPTY_NODE(&dso->rb_node))
                pr_err("DSO %s is still in rbtree when being deleted!\n",
                       dso->long_name);
        for (i = 0; i < MAP__NR_TYPES; ++i)
                symbols__delete(&dso->symbols[i]);

        if (dso->short_name_allocated) {
                zfree((char **)&dso->short_name);
                dso->short_name_allocated = false;
        }

        if (dso->long_name_allocated) {
                zfree((char **)&dso->long_name);
                dso->long_name_allocated = false;
        }

        dso__data_close(dso);
        auxtrace_cache__free(dso->auxtrace_cache);
        dso_cache__free(dso);
        dso__free_a2l(dso);
        zfree(&dso->symsrc_filename);
        pthread_mutex_destroy(&dso->lock);
        free(dso);
}

struct dso *dso__get(struct dso *dso)
{
        if (dso)
                atomic_inc(&dso->refcnt);
        return dso;
}

void dso__put(struct dso *dso)
{
        if (dso && atomic_dec_and_test(&dso->refcnt))
                dso__delete(dso);
}

void dso__set_build_id(struct dso *dso, void *build_id)
{
        memcpy(dso->build_id, build_id, sizeof(dso->build_id));
        dso->has_build_id = 1;
}

bool dso__build_id_equal(const struct dso *dso, u8 *build_id)
{
        return memcmp(dso->build_id, build_id, sizeof(dso->build_id)) == 0;
}

void dso__read_running_kernel_build_id(struct dso *dso, struct machine *machine)
{
        char path[PATH_MAX];

        if (machine__is_default_guest(machine))
                return;
        sprintf(path, "%s/sys/kernel/notes", machine->root_dir);
        if (sysfs__read_build_id(path, dso->build_id,
                                 sizeof(dso->build_id)) == 0)
                dso->has_build_id = true;
}

int dso__kernel_module_get_build_id(struct dso *dso,
                                    const char *root_dir)
{
        char filename[PATH_MAX];
        /*
         * kernel module short names are of the form "[module]" and
         * we need just "module" here.
         */
        const char *name = dso->short_name + 1;

        snprintf(filename, sizeof(filename),
                 "%s/sys/module/%.*s/notes/.note.gnu.build-id",
                 root_dir, (int)strlen(name) - 1, name);

        if (sysfs__read_build_id(filename, dso->build_id,
                                 sizeof(dso->build_id)) == 0)
                dso->has_build_id = true;

        return 0;
}

bool __dsos__read_build_ids(struct list_head *head, bool with_hits)
{
        bool have_build_id = false;
        struct dso *pos;

        list_for_each_entry(pos, head, node) {
                if (with_hits && !pos->hit)
                        continue;
                if (pos->has_build_id) {
                        have_build_id = true;
                        continue;
                }
                if (filename__read_build_id(pos->long_name, pos->build_id,
                                            sizeof(pos->build_id)) > 0) {
                        have_build_id     = true;
                        pos->has_build_id = true;
                }
        }

        return have_build_id;
}

void __dsos__add(struct dsos *dsos, struct dso *dso)
{
        list_add_tail(&dso->node, &dsos->head);
        __dso__findlink_by_longname(&dsos->root, dso, NULL);
        /*
         * It is now in the linked list, grab a reference, then garbage collect
         * this when needing memory, by looking at LRU dso instances in the
         * list with atomic_read(&dso->refcnt) == 1, i.e. no references
         * anywhere besides the one for the list, do, under a lock for the
         * list: remove it from the list, then a dso__put(), that probably will
         * be the last and will then call dso__delete(), end of life.
         *
         * That, or at the end of the 'struct machine' lifetime, when all
         * 'struct dso' instances will be removed from the list, in
         * dsos__exit(), if they have no other reference from some other data
         * structure.
         *
         * E.g.: after processing a 'perf.data' file and storing references
         * to objects instantiated while processing events, we will have
         * references to the 'thread', 'map', 'dso' structs all from 'struct
         * hist_entry' instances, but we may not need anything not referenced,
         * so we might as well call machines__exit()/machines__delete() and
         * garbage collect it.
         */
        dso__get(dso);
}

void dsos__add(struct dsos *dsos, struct dso *dso)
{
        pthread_rwlock_wrlock(&dsos->lock);
        __dsos__add(dsos, dso);
        pthread_rwlock_unlock(&dsos->lock);
}

struct dso *__dsos__find(struct dsos *dsos, const char *name, bool cmp_short)
{
        struct dso *pos;

        if (cmp_short) {
                list_for_each_entry(pos, &dsos->head, node)
                        if (strcmp(pos->short_name, name) == 0)
                                return pos;
                return NULL;
        }
        return __dso__find_by_longname(&dsos->root, name);
}

struct dso *dsos__find(struct dsos *dsos, const char *name, bool cmp_short)
{
        struct dso *dso;
        pthread_rwlock_rdlock(&dsos->lock);
        dso = __dsos__find(dsos, name, cmp_short);
        pthread_rwlock_unlock(&dsos->lock);
        return dso;
}

struct dso *__dsos__addnew(struct dsos *dsos, const char *name)
{
        struct dso *dso = dso__new(name);

        if (dso != NULL) {
                __dsos__add(dsos, dso);
                dso__set_basename(dso);
                /* Put dso here because __dsos_add already got it */
                dso__put(dso);
        }
        return dso;
}

struct dso *__dsos__findnew(struct dsos *dsos, const char *name)
{
        struct dso *dso = __dsos__find(dsos, name, false);

        return dso ? dso : __dsos__addnew(dsos, name);
}

struct dso *dsos__findnew(struct dsos *dsos, const char *name)
{
        struct dso *dso;
        pthread_rwlock_wrlock(&dsos->lock);
        dso = dso__get(__dsos__findnew(dsos, name));
        pthread_rwlock_unlock(&dsos->lock);
        return dso;
}

size_t __dsos__fprintf_buildid(struct list_head *head, FILE *fp,
                               bool (skip)(struct dso *dso, int parm), int parm)
{
        struct dso *pos;
        size_t ret = 0;

        list_for_each_entry(pos, head, node) {
                if (skip && skip(pos, parm))
                        continue;
                ret += dso__fprintf_buildid(pos, fp);
                ret += fprintf(fp, " %s\n", pos->long_name);
        }
        return ret;
}

size_t __dsos__fprintf(struct list_head *head, FILE *fp)
{
        struct dso *pos;
        size_t ret = 0;

        list_for_each_entry(pos, head, node) {
                int i;
                for (i = 0; i < MAP__NR_TYPES; ++i)
                        ret += dso__fprintf(pos, i, fp);
        }

        return ret;
}

size_t dso__fprintf_buildid(struct dso *dso, FILE *fp)
{
        char sbuild_id[BUILD_ID_SIZE * 2 + 1];

        build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id);
        return fprintf(fp, "%s", sbuild_id);
}

size_t dso__fprintf(struct dso *dso, enum map_type type, FILE *fp)
{
        struct rb_node *nd;
        size_t ret = fprintf(fp, "dso: %s (", dso->short_name);

        if (dso->short_name != dso->long_name)
                ret += fprintf(fp, "%s, ", dso->long_name);
        ret += fprintf(fp, "%s, %sloaded, ", map_type__name[type],
                       dso__loaded(dso, type) ? "" : "NOT ");
        ret += dso__fprintf_buildid(dso, fp);
        ret += fprintf(fp, ")\n");
        for (nd = rb_first(&dso->symbols[type]); nd; nd = rb_next(nd)) {
                struct symbol *pos = rb_entry(nd, struct symbol, rb_node);
                ret += symbol__fprintf(pos, fp);
        }

        return ret;
}

enum dso_type dso__type(struct dso *dso, struct machine *machine)
{
        int fd;
        enum dso_type type = DSO__TYPE_UNKNOWN;

        fd = dso__data_get_fd(dso, machine);
        if (fd >= 0) {
                type = dso__type_fd(fd);
                dso__data_put_fd(dso);
        }

        return type;
}

int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
{
        int idx, errnum = dso->load_errno;
        /*
         * This must have a same ordering as the enum dso_load_errno.
         */
        static const char *dso_load__error_str[] = {
        "Internal tools/perf/ library error",
        "Invalid ELF file",
        "Can not read build id",
        "Mismatching build id",
        "Decompression failure",
        };

        BUG_ON(buflen == 0);

        if (errnum >= 0) {
                const char *err = strerror_r(errnum, buf, buflen);

                if (err != buf)
                        scnprintf(buf, buflen, "%s", err);

                return 0;
        }

        if (errnum <  __DSO_LOAD_ERRNO__START || errnum >= __DSO_LOAD_ERRNO__END)
                return -1;

        idx = errnum - __DSO_LOAD_ERRNO__START;
        scnprintf(buf, buflen, "%s", dso_load__error_str[idx]);
        return 0;
}