thread_map.c

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#include <dirent.h>
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include "strlist.h"
#include <string.h>
#include "thread_map.h"

/* Skip "." and ".." directories */
static int filter(const struct dirent *dir)
{
    if (dir->d_name[0] == '.')
        return 0;
    else
        return 1;
}

struct thread_map *thread_map__new_by_pid(pid_t pid)
{
    struct thread_map *threads;
    char name[256];
    int items;
    struct dirent **namelist = NULL;
    int i;

    sprintf(name, "/proc/%d/task", pid);
    items = scandir(name, &namelist, filter, NULL);
    if (items <= 0)
        return NULL;

    threads = malloc(sizeof(*threads) + sizeof(pid_t) * items);
    if (threads != NULL) {
        for (i = 0; i < items; i++)
            threads->map[i] = atoi(namelist[i]->d_name);
        threads->nr = items;
    }

    for (i=0; i<items; i++)
        free(namelist[i]);
    free(namelist);

    return threads;
}

struct thread_map *thread_map__new_by_tid(pid_t tid)
{
    struct thread_map *threads = malloc(sizeof(*threads) + sizeof(pid_t));

    if (threads != NULL) {
        threads->map[0] = tid;
        threads->nr = 1;
    }

    return threads;
}

struct thread_map *thread_map__new_by_uid(uid_t uid)
{
    DIR *proc;
    int max_threads = 32, items, i;
    char path[256];
    struct dirent dirent, *next, **namelist = NULL;
    struct thread_map *threads = malloc(sizeof(*threads) +
                        max_threads * sizeof(pid_t));
    if (threads == NULL)
        goto out;

    proc = opendir("/proc");
    if (proc == NULL)
        goto out_free_threads;

    threads->nr = 0;

    while (!readdir_r(proc, &dirent, &next) && next) {
        char *end;
        bool grow = false;
        struct stat st;
        pid_t pid = strtol(dirent.d_name, &end, 10);

        if (*end) /* only interested in proper numerical dirents */
            continue;

        snprintf(path, sizeof(path), "/proc/%s", dirent.d_name);

        if (stat(path, &st) != 0)
            continue;

        if (st.st_uid != uid)
            continue;

        snprintf(path, sizeof(path), "/proc/%d/task", pid);
        items = scandir(path, &namelist, filter, NULL);
        if (items <= 0)
            goto out_free_closedir;

        while (threads->nr + items >= max_threads) {
            max_threads *= 2;
            grow = true;
        }

        if (grow) {
            struct thread_map *tmp;

            tmp = realloc(threads, (sizeof(*threads) +
                        max_threads * sizeof(pid_t)));
            if (tmp == NULL)
                goto out_free_namelist;

            threads = tmp;
        }

        for (i = 0; i < items; i++)
            threads->map[threads->nr + i] = atoi(namelist[i]->d_name);

        for (i = 0; i < items; i++)
            free(namelist[i]);
        free(namelist);

        threads->nr += items;
    }

out_closedir:
    closedir(proc);
out:
    return threads;

out_free_threads:
    free(threads);
    return NULL;

out_free_namelist:
    for (i = 0; i < items; i++)
        free(namelist[i]);
    free(namelist);

out_free_closedir:
    free(threads);
    threads = NULL;
    goto out_closedir;
}

struct thread_map *thread_map__new(pid_t pid, pid_t tid, uid_t uid)
{
    if (pid != -1)
        return thread_map__new_by_pid(pid);

    if (tid == -1 && uid != UINT_MAX)
        return thread_map__new_by_uid(uid);

    return thread_map__new_by_tid(tid);
}

static struct thread_map *thread_map__new_by_pid_str(const char *pid_str)
{
    struct thread_map *threads = NULL, *nt;
    char name[256];
    int items, total_tasks = 0;
    struct dirent **namelist = NULL;
    int i, j = 0;
    pid_t pid, prev_pid = INT_MAX;
    char *end_ptr;
    struct str_node *pos;
    struct strlist *slist = strlist__new(false, pid_str);

    if (!slist)
        return NULL;

    strlist__for_each(pos, slist) {
        pid = strtol(pos->s, &end_ptr, 10);

        if (pid == INT_MIN || pid == INT_MAX ||
            (*end_ptr != '\0' && *end_ptr != ','))
            goto out_free_threads;

        if (pid == prev_pid)
            continue;

        sprintf(name, "/proc/%d/task", pid);
        items = scandir(name, &namelist, filter, NULL);
        if (items <= 0)
            goto out_free_threads;

        total_tasks += items;
        nt = realloc(threads, (sizeof(*threads) +
                       sizeof(pid_t) * total_tasks));
        if (nt == NULL)
            goto out_free_namelist;

        threads = nt;

        for (i = 0; i < items; i++) {
            threads->map[j++] = atoi(namelist[i]->d_name);
            free(namelist[i]);
        }
        threads->nr = total_tasks;
        free(namelist);
    }

out:
    strlist__delete(slist);
    return threads;

out_free_namelist:
    for (i = 0; i < items; i++)
        free(namelist[i]);
    free(namelist);

out_free_threads:
    free(threads);
    threads = NULL;
    goto out;
}

static struct thread_map *thread_map__new_by_tid_str(const char *tid_str)
{
    struct thread_map *threads = NULL, *nt;
    int ntasks = 0;
    pid_t tid, prev_tid = INT_MAX;
    char *end_ptr;
    struct str_node *pos;
    struct strlist *slist;

    /* perf-stat expects threads to be generated even if tid not given */
    if (!tid_str) {
        threads = malloc(sizeof(*threads) + sizeof(pid_t));
        if (threads != NULL) {
            threads->map[0] = -1;
            threads->nr = 1;
        }
        return threads;
    }

    slist = strlist__new(false, tid_str);
    if (!slist)
        return NULL;

    strlist__for_each(pos, slist) {
        tid = strtol(pos->s, &end_ptr, 10);

        if (tid == INT_MIN || tid == INT_MAX ||
            (*end_ptr != '\0' && *end_ptr != ','))
            goto out_free_threads;

        if (tid == prev_tid)
            continue;

        ntasks++;
        nt = realloc(threads, sizeof(*threads) + sizeof(pid_t) * ntasks);

        if (nt == NULL)
            goto out_free_threads;

        threads = nt;
        threads->map[ntasks - 1] = tid;
        threads->nr      = ntasks;
    }
out:
    return threads;

out_free_threads:
    free(threads);
    threads = NULL;
    goto out;
}

struct thread_map *thread_map__new_str(const char *pid, const char *tid,
                       uid_t uid)
{
    if (pid)
        return thread_map__new_by_pid_str(pid);

    if (!tid && uid != UINT_MAX)
        return thread_map__new_by_uid(uid);

    return thread_map__new_by_tid_str(tid);
}

void thread_map__delete(struct thread_map *threads)
{
    free(threads);
}

size_t thread_map__fprintf(struct thread_map *threads, FILE *fp)
{
    int i;
    size_t printed = fprintf(fp, "%d thread%s: ",
                 threads->nr, threads->nr > 1 ? "s" : "");
    for (i = 0; i < threads->nr; ++i)
        printed += fprintf(fp, "%s%d", i ? ", " : "", threads->map[i]);

    return printed + fprintf(fp, "\n");
}