gen/assumes.c

   1 #include <dispatch/dispatch.h>
   2 #include <uuid/uuid.h>
   3 #include <sys/types.h>
   4 #include <sys/sysctl.h>
   5 #include <mach-o/loader.h>
   6 #include <sys/types.h>
   7 #include <execinfo.h>
   8 #include <stdio.h>
   9 #include <dlfcn.h>
  10 #include <asl.h>
  11 #include <errno.h>
  12 #include "assumes.h"
  13
  14 /* TODO: Re-enable after deciding how best to interact with this symbol. */
  15 /*
  16  * NOTE: 8006611: converted to using libCrashReporterClient.a, so shouldn't
  17  * use __crashreporter_info__.
  18  */
  19 #if 0
  20 static char __crashreporter_info_buff__[2048];
  21 const char *__crashreporter_info__ = &__crashreporter_info_buff__[0];
  22 asm (".desc __crashreporter_info__, 0x10");
  23 #endif
  24
  25 #define osx_atomic_cmpxchg(p, o, n) __sync_bool_compare_and_swap((p), (o), (n))
  26
  27 static const char *
  28 _osx_basename(const char *p)
  29 {
  30         return ((strrchr(p, '/') ? : p - 1) + 1);
  31 }
  32
  33 static char *
  34 _osx_get_build(void)
  35 {
  36         static char s_build[16];
  37         static long s_once = 0;
  38         if (osx_atomic_cmpxchg(&s_once, 0, 1)) {
  39                 int mib[] = { CTL_KERN, KERN_OSVERSION };
  40                 size_t sz = sizeof(s_build);
  41
  42                 (void)sysctl(mib, 2, s_build, &sz, NULL, 0);
  43         }
  44
  45         return s_build;
  46 }
  47
  48 static void
  49 _osx_get_image_uuid(void *hdr, uuid_t uuid)
  50 {
  51 #if __LP64__
  52         struct mach_header_64 *_hdr = (struct mach_header_64 *)hdr;
  53 #else
  54         struct mach_header *_hdr = (struct mach_header *)hdr;
  55 #endif /* __LP64__ */
  56
  57         size_t i = 0;
  58         size_t next = sizeof(*_hdr);
  59         struct load_command *cur = NULL;
  60         for (i = 0; i < _hdr->ncmds; i++) {
  61                 cur = (struct load_command *)((uintptr_t)_hdr + next);
  62                 if (cur->cmd == LC_UUID) {
  63                         struct uuid_command *cmd = (struct uuid_command *)cur;
  64                         uuid_copy(uuid, cmd->uuid);
  65                         break;
  66                 }
  67                 next += cur->cmdsize;
  68         }
  69
  70         if (i == _hdr->ncmds) {
  71                 uuid_clear(uuid);
  72         }
  73 }
  74
  75 void
  76 _osx_assumes_log(uint64_t code)
  77 {
  78         Dl_info info;
  79
  80         const char *image_name = NULL;
  81         uintptr_t offset = 0;
  82         uuid_string_t uuid_str;
  83
  84         void *arr[2];
  85         /* Get our caller's address so we can look it up with dladdr(3) and
  86          * get info about the image.
  87          */
  88         if (backtrace(arr, 2) == 2) {
  89                 /* dladdr(3) returns non-zero on success... for some reason. */
  90                 if (dladdr(arr[1], &info)) {
  91                         uuid_t uuid;
  92                         _osx_get_image_uuid(info.dli_fbase, uuid);
  93
  94                         uuid_unparse(uuid, uuid_str);
  95                         image_name = _osx_basename(info.dli_fname);
  96
  97                         offset = arr[1] - info.dli_fbase;
  98                 }
  99         } else {
 100                 uuid_t null_uuid;
 101                 uuid_string_t uuid_str;
 102
 103                 uuid_clear(null_uuid);
 104                 uuid_unparse(null_uuid, uuid_str);
 105
 106                 image_name = "unknown";
 107         }
 108
 109         char name[256];
 110         (void)snprintf(name, sizeof(name), "com.apple.assumes.%s", image_name);
 111
 112         char sig[64];
 113         (void)snprintf(sig, sizeof(sig), "%s:%lu", uuid_str, offset);
 114
 115         char result[24];
 116         (void)snprintf(result, sizeof(result), "0x%llx", code);
 117
 118         char *prefix = "Bug";
 119         char message[1024];
 120         (void)snprintf(message, sizeof(message), "%s: %s: %s + %lu [%s]: %s", prefix, _osx_get_build(), image_name, offset, uuid_str, result);
 121
 122         aslmsg msg = asl_new(ASL_TYPE_MSG);
 123         if (msg != NULL) {
 124                 /* MessageTracer messages aren't logged to the regular syslog store, so
 125                  * we pre-log the message without any MessageTracer attributes so that
 126                  * we can see it in our regular syslog.
 127                  */
 128                 (void)asl_log(NULL, msg, ASL_LEVEL_ERR, "%s", message);
 129
 130                 (void)asl_set(msg, "com.apple.message.domain", name);
 131                 (void)asl_set(msg, "com.apple.message.signature", sig);
 132                 (void)asl_set(msg, "com.apple.message.value", result);
 133
 134                 (void)asl_log(NULL, msg, ASL_LEVEL_ERR, "%s", message);
 135                 asl_free(msg);
 136         }
 137 }
 138
 139 /* For osx_assert(). We need to think more about how best to set the __crashreporter_info__ string.
 140  * For example, calling into two functions will basically smash the register state at the time of
 141  * the assertion failure, causing potentially valuable information to be lost. Also, just setting
 142  * the __crashreporter_info__ to a static string only involves one instruction, whereas a function
 143  * call involves... well, more.
 144  */
 145 #if 0
 146 void
 147 osx_hardware_trap(const char *fmt, ...)
 148 {
 149         va_list ap;
 150         va_start(ap, fmt);
 151
 152         osx_hardware_trapv(fmt, ap);
 153
 154         va_end(ap);
 155 }
 156
 157 void
 158 osx_hardware_trapv(const char *fmt, va_list ap)
 159 {
 160         (void)vsnprintf(__crashreporter_info_buff__, sizeof(__crashreporter_info_buff__), fmt, ap);
 161         fflush(NULL);
 162         __builtin_trap();
 163 }
 164 #endif