tests/proc_info_list_kthreads.c

   1 /*
   2  * proc_info_list_kthreads
   3  *
   4  * list 64 bit thread ids of kernel_task
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <assert.h>
  10 #include <err.h>
  11
  12 #include <libproc.h>
  13 #include <strings.h>
  14 #include <darwintest.h>
  15 #include <TargetConditionals.h>
  16
  17 #define MAX_TRIES 20
  18 #define EXTRA_THREADS 15
  19
  20 #if TARGET_OS_OSX
  21 T_DECL(proc_info_list_kthreads,
  22        "Test to verify PROC_PIDLISTTHREADIDS returns kernel thread IDs for pid 0",
  23        T_META_ASROOT(true),
  24        T_META_CHECK_LEAKS(false))
  25 #else
  26 T_DECL(proc_info_list_kthreads,
  27        "Test to verify PROC_PIDLISTTHREADIDS returns kernel thread IDs for pid 0",
  28        T_META_ASROOT(false),
  29        T_META_CHECK_LEAKS(false))
  30 #endif /* TARGET_OS_OSX */
  31 {
  32         int buf_used = 0;
  33
  34         int thread_count = 0;
  35         uint64_t *thread_list = NULL;
  36
  37         /*
  38          * To use PROC_PIDLISTTHREADIDS, we must pass a buffer of uint64_t's for each thread ID.
  39          * However, there is a TOCTOU race between asking for the thread count
  40          * and asking for the array of identifiers.
  41          *
  42          * Because the process could have allocated more threads since last we asked
  43          * how many threads there are, we instead pass an extra slot in the array,
  44          * and try again if it used that slot.
  45          */
  46
  47         int attempt = 1;
  48         while (!thread_count && (attempt < MAX_TRIES)) {
  49                 struct proc_taskinfo ti;
  50
  51                 buf_used = proc_pidinfo(0, PROC_PIDTASKINFO, 0, &ti, sizeof(ti));
  52
  53                 T_QUIET; T_WITH_ERRNO; T_ASSERT_GT(buf_used, 0, "proc_pidinfo(PROC_PIDTASKINFO) returned a value > 0");
  54                 T_QUIET; T_ASSERT_EQ(buf_used, (int)sizeof(ti), "proc_pidinfo(PROC_PIDTASKINFO) returned size %d == %lu", buf_used, sizeof(ti));
  55
  56                 T_LOG("The kernel says it has %d threads", ti.pti_threadnum);
  57
  58                 int expected_size  = ti.pti_threadnum * (int)sizeof(uint64_t);
  59                 /* tack on five extra to detect newly allocated threads */
  60                 int allocated_size = expected_size + EXTRA_THREADS*(int)sizeof(uint64_t);
  61                 uint64_t *thread_list_tmp = malloc((size_t)allocated_size);
  62                 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(thread_list_tmp, "malloc(size = %d) failed", allocated_size);
  63
  64                 buf_used = proc_pidinfo(0, PROC_PIDLISTTHREADIDS, 0, thread_list_tmp, (int)allocated_size);
  65                 T_LOG("proc_pidinfo(PROC_PIDLISTTHREADIDS) buf_used = %d, expected_size = %d", buf_used, expected_size);
  66
  67                 if (buf_used == 0) {
  68                         T_WITH_ERRNO; T_ASSERT_FAIL("proc_pidinfo(PROC_PIDLISTTHREADIDS) failed");
  69                 }
  70                 if (buf_used == expected_size) {
  71                         /* success, we found the expected number of threads */
  72                         thread_list = thread_list_tmp;
  73                         thread_count = expected_size / (int)sizeof(uint64_t);
  74                 } else if (buf_used < expected_size) {
  75                         /* there were fewer threads than we expected, fix up the allocation */
  76                         thread_list = realloc(thread_list_tmp, (size_t)buf_used);
  77                         thread_count = buf_used / (int)sizeof(uint64_t);
  78                         T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(thread_list, "realloc(size = %d) failed", buf_used);
  79                 } else if (buf_used > expected_size) {
  80                         if (buf_used < allocated_size) {
  81                                 thread_list = realloc(thread_list_tmp, (size_t)buf_used);
  82                                 thread_count = buf_used / (int)sizeof(uint64_t);
  83                                 T_QUIET; T_WITH_ERRNO; T_ASSERT_NOTNULL(thread_list, "realloc(size = %d) failed", buf_used);
  84                         } else {
  85                                 /*
  86                                  * it used all the extra slots, meaning there are more
  87                                  * threads than we thought, try again!
  88                                  */
  89                                 T_LOG("expected %d threads, but saw an extra thread: %d",
  90                                        expected_size / (int)sizeof(uint64_t), buf_used / (int)sizeof(uint64_t));
  91                                 free(thread_list_tmp);
  92                         }
  93                 }
  94                 attempt++;
  95         }
  96         T_QUIET; T_ASSERT_LE(attempt, MAX_TRIES, "attempt <= MAX_TRIES");
  97         T_QUIET; T_ASSERT_NOTNULL(thread_list, "thread_list != NULL");
  98         T_QUIET; T_ASSERT_GT(thread_count, 0, "thread_count > 0");
  99
 100         struct proc_threadinfo pthinfo_64;
 101         for (int i = 0 ; i < thread_count ; i++) {
 102                 bzero(&pthinfo_64, sizeof(struct proc_threadinfo));
 103                 int retval = proc_pidinfo(0, PROC_PIDTHREADID64INFO, thread_list[i],
 104                                           (void *)&pthinfo_64, (uint32_t)sizeof(pthinfo_64));
 105                 T_QUIET; T_WITH_ERRNO; T_EXPECT_GT(retval, 0, "proc_pidinfo(PROC_PIDTASKINFO) returned %d", retval);
 106                 T_QUIET; T_EXPECT_EQ(retval, (int)sizeof(pthinfo_64), "proc_pidinfo(PROC_PIDTASKINFO) returned size %d == %lu",
 107                                      retval, sizeof(pthinfo_64));
 108         }
 109 }
 110