tests/preoslog.c

   1 #include <darwintest.h>
   2 #include <darwintest_utils.h>
   3 #include <sys/sysctl.h>
   4 #include <string.h>
   5 #include <errno.h>
   6
   7 /*
   8  * Any change to this structure must be reflected in iBoot / MacEFI / PanicDump / XNU Tests and vice versa.
   9  */
  10 typedef struct  __attribute__((packed)) {
  11         uint32_t magic; /* g_valid_magic if valid */
  12         uint32_t size; /* Size of the preoslog buffer including the header */
  13         uint32_t offset; /* Write pointer. Indicates where in the buffer new log entry would go */
  14         uint8_t source; /* Indicates who filled in the buffer (e.g. iboot vs MacEFI) */
  15         uint8_t wrapped; /* If equal to 1, the preoslog ring buffer wrapped at least once */
  16         char data[]; /* log buffer */
  17 } preoslog_header_t;
  18
  19 static const char* g_sysctl_kern_version = "kern.version";
  20 static const char* g_sysctl_kern_preoslog = "kern.preoslog";
  21 static const uint32_t g_valid_magic = 'LSOP';
  22
  23 /*
  24  * Defines substrings to look up in preoslog buffer.
  25  * To pass the test, one of the entries should match a substring in preoslog buffer.
  26  */
  27 static const char* g_preoslog_buffer_string[] = {"serial output"};
  28
  29 static boolean_t
  30 check_for_substrings(const char* string, size_t len)
  31 {
  32         int i;
  33         boolean_t res = FALSE;
  34
  35         for (i = 0; i < (sizeof(g_preoslog_buffer_string) / sizeof(char*)); i++) {
  36                 res = res || strnstr(string, g_preoslog_buffer_string[i], len) == NULL ? FALSE : TRUE;
  37         }
  38
  39         return res;
  40 }
  41
  42 static boolean_t
  43 is_development_kernel(void)
  44 {
  45         int ret;
  46         int dev = 0;
  47         size_t dev_size = sizeof(dev);
  48
  49         ret = sysctlbyname("kern.development", &dev, &dev_size, NULL, 0);
  50         if (ret != 0) {
  51                 return FALSE;
  52         }
  53
  54         return dev != 0;
  55 }
  56
  57 /*
  58  *       Valid cases:
  59  *       1. Development & Debug iBoot/macEFI provides a preoslog buffer.
  60  *       2. Release iBoot/macEFI doesn't provide a presoslog buffer.
  61  *       3. Development & Debug xnu provids kern.preoslog sysctl.
  62  *       4. Release xnu doesn't provide kern.preoslog sysctl.
  63  */
  64
  65 T_DECL(test_preoslog, "Validate kern.preoslog sysctl has expected log content from the boot loader")
  66 {
  67         int ret = 0;
  68         size_t size = 0;
  69         void *buffer = NULL;
  70         preoslog_header_t *header = NULL;
  71         char tmp = 0;
  72         const char *lower_buffer = NULL;
  73         size_t lower_buffer_size = 0;
  74         const char *upper_buffer = NULL;
  75         size_t upper_buffer_size = 0;
  76         boolean_t found = FALSE;
  77
  78         // kern.preoslog is writable
  79         ret = sysctlbyname(g_sysctl_kern_preoslog, buffer, &size, &tmp, sizeof(tmp));
  80         T_ASSERT_POSIX_SUCCESS(ret, "kern.preoslog write check");
  81
  82         ret = sysctlbyname(g_sysctl_kern_preoslog, NULL, &size, NULL, 0);
  83         if (!is_development_kernel()) {
  84                 // kern.preoslog mustn't exist on release builds of xnu
  85                 T_ASSERT_NE(ret, 0, "get size kern.preoslog ret != 0 on release builds");
  86                 T_ASSERT_POSIX_ERROR(ret, ENOENT, " get size kern.preoslog errno==ENOENT on release builds");
  87                 return;
  88         }
  89
  90         /*
  91          * Everything below is applicable only to development & debug xnu
  92          */
  93
  94         T_ASSERT_POSIX_SUCCESS(ret, "get size for kern.preoslog");
  95         if (size == 0) {
  96                 // No preoslog buffer available, valid case if iboot is release
  97                 return;
  98         }
  99
 100         buffer = calloc(size, sizeof(char));
 101         T_ASSERT_NOTNULL(buffer, "allocate buffer for preoslog");
 102
 103         ret = sysctlbyname(g_sysctl_kern_preoslog, buffer, &size, NULL, 0);
 104         T_ASSERT_POSIX_SUCCESS(ret, "get preoslog buffer");
 105
 106         header = (preoslog_header_t *)buffer;
 107         T_ASSERT_EQ(header->magic, g_valid_magic, "check preoslog header magic - expected %#x, given %#x", g_valid_magic, header->magic);
 108         T_ASSERT_EQ(header->size, size, "check preoslog sizes - expected %zu, given %zu", size, header->size);
 109         T_ASSERT_LT(header->offset, header->size - sizeof(*header), "check write offset");
 110
 111         lower_buffer = header->data;
 112         lower_buffer_size = header->offset + 1;
 113         upper_buffer = lower_buffer + lower_buffer_size;
 114         upper_buffer_size = header->size - lower_buffer_size - sizeof(*header);
 115         if (header->wrapped) {
 116                 found = check_for_substrings(upper_buffer, upper_buffer_size);
 117         }
 118
 119         found = found || check_for_substrings(lower_buffer, lower_buffer_size);
 120         T_ASSERT_TRUE(found, "Verify buffer content");
 121
 122         free(buffer);
 123         buffer = NULL;
 124         header = NULL;
 125 }