Fix randomizer
Relying on the system randomizer for unit tests leads to cases where we
don't get deterministic results, which causes inconsistent results.
These random results don't need to be secure, so reimplement as a simple
linear feedback shift register[1]. This makes our unit tests now
produce the same output every time we call generate.
Note, this change showed a weakness in our testing, where timestamps
relied on different rules for ir->cper versus cper->ir. hour 24 should
be allowed.
[1] https://en.wikipedia.org/wiki/Linear-feedback_shift_register
Change-Id: I0756b086c8ea5fb934e450f5d33e3ae0036868b3
Signed-off-by: Ed Tanous <ed@tanous.net>
diff --git a/cper-utils.c b/cper-utils.c
index ae71dc4..0821a16 100644
--- a/cper-utils.c
+++ b/cper-utils.c
@@ -342,7 +342,7 @@
return -1;
}
int hours = bcd_to_int(timestamp->Hours);
- if (hours >= 24) {
+ if (hours > 24) {
return -1;
}
int minutes = bcd_to_int(timestamp->Minutes);
diff --git a/generator/cper-generate.c b/generator/cper-generate.c
index b1b105b..2cee1e0 100644
--- a/generator/cper-generate.c
+++ b/generator/cper-generate.c
@@ -24,9 +24,6 @@
void generate_cper_record(char **types, UINT16 num_sections, FILE *out,
GEN_VALID_BITS_TEST_TYPE validBitsType)
{
- //Initialise randomiser.
- init_random(0);
-
//Generate the sections.
void *sections[num_sections];
size_t section_lengths[num_sections];
@@ -199,7 +196,7 @@
//If the section name is "unknown", simply generate a random bytes section.
int section_generated = 0;
if (strcmp(type, "unknown") == 0) {
- length = generate_random_section(location, rand() % 256);
+ length = generate_random_section(location, ALL_VALID);
section_generated = 1;
} else {
//Function defined section, switch on the type, generate accordingly.
diff --git a/generator/gen-utils.c b/generator/gen-utils.c
index 46642b2..b299f7b 100644
--- a/generator/gen-utils.c
+++ b/generator/gen-utils.c
@@ -8,6 +8,22 @@
#include <libcper/BaseTypes.h>
#include <libcper/generator/gen-utils.h>
+UINT32 lfsr = 0xACE1u;
+
+void cper_rand_seed(UINT32 seed)
+{
+ lfsr = seed;
+}
+
+UINT32 cper_rand()
+{
+ lfsr |= lfsr == 0; // if x == 0, set x = 1 instead
+ lfsr ^= (lfsr & 0x0007ffff) << 13;
+ lfsr ^= lfsr >> 17;
+ lfsr ^= (lfsr & 0x07ffffff) << 5;
+ return lfsr;
+}
+
//Generates a random section of the given byte size, saving the result to the given location.
//Returns the length of the section as passed in.
size_t generate_random_section(void **location, size_t size)
@@ -21,7 +37,7 @@
{
UINT8 *bytes = malloc(size);
for (size_t i = 0; i < size; i++) {
- bytes[i] = rand();
+ bytes[i] = cper_rand();
}
return bytes;
}
@@ -36,13 +52,7 @@
*error_section &= 0x7FFFFF; //Reserved bits 23-63
//Ensure error type has a valid value.
- *(start + 1) =
- CPER_ERROR_TYPES_KEYS[rand() % (sizeof(CPER_ERROR_TYPES_KEYS) /
- sizeof(int))];
-}
-
-//Initializes the random seed for rand() using the current time.
-void init_random()
-{
- srand(1);
+ *(start + 1) = CPER_ERROR_TYPES_KEYS[cper_rand() %
+ (sizeof(CPER_ERROR_TYPES_KEYS) /
+ sizeof(int))];
}
diff --git a/generator/sections/gen-section-arm.c b/generator/sections/gen-section-arm.c
index c181663..ded953d 100644
--- a/generator/sections/gen-section-arm.c
+++ b/generator/sections/gen-section-arm.c
@@ -21,8 +21,8 @@
GEN_VALID_BITS_TEST_TYPE validBitsType)
{
//Set up for generation of error/context structures.
- UINT16 error_structure_num = rand() % 4 + 1; //Must be at least 1.
- UINT16 context_structure_num = rand() % 3 + 1;
+ UINT16 error_structure_num = cper_rand() % 4 + 1; //Must be at least 1.
+ UINT16 context_structure_num = cper_rand() % 3 + 1;
void *error_structures[error_structure_num];
void *context_structures[context_structure_num];
size_t context_structure_lengths[context_structure_num];
@@ -37,7 +37,7 @@
}
//Determine a random amount of vendor specific info.
- size_t vendor_info_len = rand() % 16 + 4;
+ size_t vendor_info_len = cper_rand() % 16 + 4;
//Create the section as a whole.
size_t total_len = 40 + (error_structure_num * ARM_ERROR_INFO_SIZE);
@@ -55,7 +55,7 @@
*section_length = total_len;
//Error affinity.
- *(section + 12) = rand() % 4;
+ *(section + 12) = cper_rand() % 4;
//Reserved zero bytes.
UINT32 *validation = (UINT32 *)section;
@@ -87,7 +87,7 @@
for (size_t i = 0; i < vendor_info_len; i++) {
//Ensure only ascii is used so we don't
// fail base64E
- *cur_pos = rand() % 127 + 1;
+ *cur_pos = cper_rand() % 127 + 1;
cur_pos += 1;
}
@@ -106,7 +106,7 @@
*(error_info + 1) = ARM_ERROR_INFO_SIZE;
//Type of error.
- UINT8 error_type = rand() % 3;
+ UINT8 error_type = cper_rand() % 3;
*(error_info + 4) = error_type;
//Reserved bits for error information.
@@ -162,7 +162,7 @@
size_t generate_arm_context_info(void **location)
{
//Initial length is 8 bytes. Add extra based on type.
- UINT16 reg_type = rand() % 9;
+ UINT16 reg_type = cper_rand() % 9;
UINT32 reg_size = 0;
//Set register size.
diff --git a/generator/sections/gen-section-ccix-per.c b/generator/sections/gen-section-ccix-per.c
index e648cba..2547d8d 100644
--- a/generator/sections/gen-section-ccix-per.c
+++ b/generator/sections/gen-section-ccix-per.c
@@ -16,7 +16,7 @@
{
//Create a random length for the CCIX PER log.
//The log attached here does not necessarily conform to the CCIX specification, and is simply random.
- int log_len = (rand() % 5 + 1) * 32;
+ int log_len = (cper_rand() % 5 + 1) * 32;
//Create random bytes.
int size = 16 + log_len;
diff --git a/generator/sections/gen-section-cxl-component.c b/generator/sections/gen-section-cxl-component.c
index 615a152..6c4e60e 100644
--- a/generator/sections/gen-section-cxl-component.c
+++ b/generator/sections/gen-section-cxl-component.c
@@ -16,7 +16,7 @@
{
//Create a random length for the CXL component event log.
//The logs attached here do not necessarily conform to the specification, and are simply random.
- int log_len = rand() % 64;
+ int log_len = cper_rand() % 64;
//Create random bytes.
int size = 32 + log_len;
diff --git a/generator/sections/gen-section-cxl-protocol.c b/generator/sections/gen-section-cxl-protocol.c
index 1918d68..e171c7f 100644
--- a/generator/sections/gen-section-cxl-protocol.c
+++ b/generator/sections/gen-section-cxl-protocol.c
@@ -16,15 +16,15 @@
{
//Create a random length for the CXL DVSEC and CXL error log.
//The logs attached here do not necessarily conform to the specification, and are simply random.
- int dvsec_len = rand() % 64;
- int error_log_len = rand() % 64;
+ int dvsec_len = cper_rand() % 64;
+ int error_log_len = cper_rand() % 64;
//Create random bytes.
int size = 116 + dvsec_len + error_log_len;
UINT8 *bytes = generate_random_bytes(size);
//Set CXL agent type.
- int cxl_agent_type = rand() % 2;
+ int cxl_agent_type = cper_rand() % 2;
*(bytes + 8) = cxl_agent_type;
//Set reserved areas to zero.
diff --git a/generator/sections/gen-section-dmar.c b/generator/sections/gen-section-dmar.c
index 7c2a85f..4062338 100644
--- a/generator/sections/gen-section-dmar.c
+++ b/generator/sections/gen-section-dmar.c
@@ -25,10 +25,10 @@
*(reserved + 1) = 0;
//Set expected values.
- *(bytes + 4) = rand() % 0xC; //Fault reason.
- *(bytes + 5) = rand() % 2; //Access type.
- *(bytes + 6) = rand() % 2; //Address type.
- *(bytes + 7) = rand() % 2 + 1; //Architecture type.
+ *(bytes + 4) = cper_rand() % 0xC; //Fault reason.
+ *(bytes + 5) = cper_rand() % 2; //Access type.
+ *(bytes + 6) = cper_rand() % 2; //Address type.
+ *(bytes + 7) = cper_rand() % 2 + 1; //Architecture type.
//Set return values, exit.
*location = bytes;
diff --git a/generator/sections/gen-section-firmware.c b/generator/sections/gen-section-firmware.c
index 6ec4b88..bf8a7ee 100644
--- a/generator/sections/gen-section-firmware.c
+++ b/generator/sections/gen-section-firmware.c
@@ -25,10 +25,10 @@
}
//Set expected values.
- *(bytes + 1) = 2; //Revision, referenced version of spec is 2.
+ *(bytes + 1) = 2; //Revision, referenced version of spec is 2.
UINT64 *record_id = (UINT64 *)(bytes + 8);
- *record_id = 0; //Record ID, should be forced to NULL.
- *bytes = rand() % 3; //Record type.
+ *record_id = 0; //Record ID, should be forced to NULL.
+ *bytes = cper_rand() % 3; //Record type.
//Set return values, exit.
*location = bytes;
diff --git a/generator/sections/gen-section-generic.c b/generator/sections/gen-section-generic.c
index 54de52e..4d25559 100644
--- a/generator/sections/gen-section-generic.c
+++ b/generator/sections/gen-section-generic.c
@@ -33,7 +33,7 @@
for (int i = 0; i < 128; i++) {
UINT8 *byte = start_byte + 24 + i;
//Ensure only ascii is used
- *byte = rand() % 127 + 1;
+ *byte = cper_rand() % 127 + 1;
//Null terminate last byte.
if (i == 127) {
diff --git a/generator/sections/gen-section-ia32x64.c b/generator/sections/gen-section-ia32x64.c
index 647f77d..8507d1b 100644
--- a/generator/sections/gen-section-ia32x64.c
+++ b/generator/sections/gen-section-ia32x64.c
@@ -20,8 +20,8 @@
GEN_VALID_BITS_TEST_TYPE validBitsType)
{
//Set up for generation of error/context structures.
- UINT16 error_structure_num = rand() % 4 + 1;
- UINT16 context_structure_num = rand() % 4 + 1;
+ UINT16 error_structure_num = cper_rand() % 4 + 1;
+ UINT16 context_structure_num = cper_rand() % 4 + 1;
void *error_structures[error_structure_num];
void *context_structures[context_structure_num];
size_t context_structure_lengths[context_structure_num];
@@ -99,7 +99,7 @@
//Create a random type of error structure.
EFI_GUID *guid = (EFI_GUID *)error_structure;
UINT64 *check_info = (UINT64 *)(error_structure + 24);
- int error_structure_type = rand() % 4;
+ int error_structure_type = cper_rand() % 4;
switch (error_structure_type) {
//Cache
case 0:
@@ -149,16 +149,16 @@
size_t generate_ia32x64_context_structure(void **location)
{
//Initial length is 16 bytes. Add extra based on type.
- int reg_type = rand() % 8;
+ int reg_type = cper_rand() % 8;
int reg_size = 0;
//Set register size.
if (reg_type == 2) {
- reg_size = 92; //IA32 registers.
+ reg_size = 92; //IA32 registers.
} else if (reg_type == 3) {
- reg_size = 244; //x64 registers.
+ reg_size = 244; //x64 registers.
} else {
- reg_size = (rand() % 5 + 1) * 32; //Not table defined.
+ reg_size = (cper_rand() % 5 + 1) * 32; //Not table defined.
}
//Create structure randomly.
diff --git a/generator/sections/gen-section-memory.c b/generator/sections/gen-section-memory.c
index a45f0ce..866fe0c 100644
--- a/generator/sections/gen-section-memory.c
+++ b/generator/sections/gen-section-memory.c
@@ -30,7 +30,7 @@
*(bytes + 73) &= ~0x1C; //Extended bits 2-4
//Fix values that could be above range.
- *(bytes + 72) = rand() % 16; //Memory error type
+ *(bytes + 72) = cper_rand() % 16; //Memory error type
//Fix error status.
create_valid_error_section(bytes + 8);
@@ -61,8 +61,8 @@
*(bytes + 63) = 0; //Reserved byte 63
//Fix values that could be above range.
- *(bytes + 61) = rand() % 16; //Memory error type
- *(bytes + 62) = rand() % 2; //Status
+ *(bytes + 61) = cper_rand() % 16; //Memory error type
+ *(bytes + 62) = cper_rand() % 2; //Status
//Fix error status.
create_valid_error_section(bytes + 8);
diff --git a/generator/sections/gen-section-nvidia.c b/generator/sections/gen-section-nvidia.c
index a06f545..83b8845 100644
--- a/generator/sections/gen-section-nvidia.c
+++ b/generator/sections/gen-section-nvidia.c
@@ -26,8 +26,6 @@
"MCF", "GPU-STATUS", "GPU-CONTNMT", "SMMU",
};
- init_random();
-
//Create random bytes.
int numRegs = 6;
size_t size = offsetof(EFI_NVIDIA_ERROR_DATA, Register) +
@@ -45,7 +43,8 @@
nvidia_error->Severity %= 4;
//Signature.
- int idx_random = rand() % (sizeof(signatures) / sizeof(signatures[0]));
+ int idx_random =
+ cper_rand() % (sizeof(signatures) / sizeof(signatures[0]));
strncpy(nvidia_error->Signature, signatures[idx_random],
sizeof(nvidia_error->Signature) - 1);
nvidia_error->Signature[sizeof(nvidia_error->Signature) - 1] = '\0';
diff --git a/generator/sections/gen-section-pci-bus.c b/generator/sections/gen-section-pci-bus.c
index ca0f255..c0e59c0 100644
--- a/generator/sections/gen-section-pci-bus.c
+++ b/generator/sections/gen-section-pci-bus.c
@@ -33,7 +33,7 @@
//Fix values that could be above range.
UINT16 *error_type = (UINT16 *)(bytes + 16);
- *error_type = rand() % 8;
+ *error_type = cper_rand() % 8;
//Fix error status.
create_valid_error_section(bytes + 8);
diff --git a/generator/sections/gen-section-pci-dev.c b/generator/sections/gen-section-pci-dev.c
index 6deac59..3982d63 100644
--- a/generator/sections/gen-section-pci-dev.c
+++ b/generator/sections/gen-section-pci-dev.c
@@ -15,8 +15,8 @@
GEN_VALID_BITS_TEST_TYPE validBitsType)
{
//Generate how many register pairs will be attached to this section.
- UINT32 num_memory_pairs = rand() % 4;
- UINT32 num_io_pairs = rand() % 4;
+ UINT32 num_memory_pairs = cper_rand() % 4;
+ UINT32 num_io_pairs = cper_rand() % 4;
UINT32 num_registers = num_memory_pairs + num_io_pairs;
//Create random bytes.
diff --git a/generator/sections/gen-section-pcie.c b/generator/sections/gen-section-pcie.c
index db9dfd9..2111d28 100644
--- a/generator/sections/gen-section-pcie.c
+++ b/generator/sections/gen-section-pcie.c
@@ -36,14 +36,14 @@
*(bytes + 39) = 0; //Device ID byte 15
//Set expected values.
- int minor = rand() % 128;
- int major = rand() % 128;
+ int minor = cper_rand() % 128;
+ int major = cper_rand() % 128;
*version = int_to_bcd(minor);
*version |= int_to_bcd(major) << 8;
//Fix values that could be above range.
UINT32 *port_type = (UINT32 *)(bytes + 8);
- *port_type = PCIE_PORT_TYPES[rand() %
+ *port_type = PCIE_PORT_TYPES[cper_rand() %
(sizeof(PCIE_PORT_TYPES) / sizeof(int))];
//Set return values, exit.
diff --git a/include/libcper/generator/gen-utils.h b/include/libcper/generator/gen-utils.h
index 33ae2ab..5ba61d1 100644
--- a/include/libcper/generator/gen-utils.h
+++ b/include/libcper/generator/gen-utils.h
@@ -16,7 +16,10 @@
size_t generate_random_section(void **location, size_t size);
UINT8 *generate_random_bytes(size_t size);
-void init_random();
+
+void cper_rand_seed(UINT32 seed);
+UINT32 cper_rand();
+
void create_valid_error_section(UINT8 *start);
#ifdef __cplusplus