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authorMattias Andrée <maandree@kth.se>2024-01-28 16:34:27 +0100
committerMattias Andrée <maandree@kth.se>2024-01-28 16:34:27 +0100
commit71811470be4f182b623510cf92ea5cfff16df172 (patch)
tree7f5e35dbdc22bd64dec1e8b62ffc9214544ae466
parentFix typo (diff)
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Add libsimple_generate_seed and libsimple_srand
Signed-off-by: Mattias Andrée <maandree@kth.se>
Diffstat (limited to '')
-rw-r--r--Makefile3
-rw-r--r--generate_seed.c59
-rw-r--r--libsimple.h1
-rw-r--r--libsimple/random.h22
-rw-r--r--srand.c18
5 files changed, 103 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index cc99bc0..38f2537 100644
--- a/Makefile
+++ b/Makefile
@@ -44,6 +44,7 @@ SUBHDR =\
libsimple/printf.h\
libsimple/pvalloc.h\
libsimple/pvallocz.h\
+ libsimple/random.h\
libsimple/realloc.h\
libsimple/search.h\
libsimple/str.h\
@@ -224,6 +225,7 @@ OBJ =\
ewcsdup.o\
ewcsndup.o\
ewmemdup.o\
+ generate_seed.o\
getenv_e.o\
getenv_ne.o\
gmtime.o\
@@ -318,6 +320,7 @@ OBJ =\
reallocf.o\
reallocfn.o\
reallocn.o\
+ srand.o\
stpmove.o\
stpnmove.o\
stpnset.o\
diff --git a/generate_seed.c b/generate_seed.c
new file mode 100644
index 0000000..cce274f
--- /dev/null
+++ b/generate_seed.c
@@ -0,0 +1,59 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+#include <sys/auxv.h>
+
+
+unsigned int
+libsimple_generate_seed(void) /* TODO add test */
+{
+ uintptr_t longseed = 1;
+ void *ptr;
+ uintptr_t ptri;
+ unsigned int seed;
+ struct timespec ts;
+ uint8_t (*at_random)[16];
+ size_t i;
+
+ if (!clock_gettime(CLOCK_REALTIME, &ts))
+ longseed ^= (uintptr_t)ts.tv_sec * (uintptr_t)1000000000UL + (uintptr_t)ts.tv_nsec;
+
+ ptr = malloc(1);
+ ptri = (uintptr_t)ptr;
+ free(ptr);
+ longseed ^= ptri;
+ longseed ^= (uintptr_t)&ptri;
+ longseed ^= (uintptr_t)clock();
+
+ if (!clock_gettime(CLOCK_MONOTONIC_RAW, &ts))
+ longseed ^= (uintptr_t)ts.tv_sec * (uintptr_t)1000000000UL + (uintptr_t)ts.tv_nsec;
+
+ ptri = (uintptr_t)getauxval(AT_RANDOM);
+ if (ptri) {
+ at_random = (void *)ptri;
+ for (i = 0; i < ELEMSOF(*at_random); i++)
+ longseed ^= (*at_random)[i] << (i % sizeof(longseed) * (size_t)CHAR_BIT);
+ }
+
+ seed = 0;
+ while (longseed) {
+ seed ^= (unsigned int)longseed;
+ longseed >>= sizeof(unsigned int) * (CHAR_BIT - 1);
+ longseed >>= sizeof(unsigned int);
+ }
+
+ return seed;
+}
+
+
+#else
+#include "test.h"
+
+int
+main(void)
+{
+ return 0;
+}
+
+#endif
diff --git a/libsimple.h b/libsimple.h
index 9cc0f8f..1cd7806 100644
--- a/libsimple.h
+++ b/libsimple.h
@@ -165,6 +165,7 @@
#include "libsimple/strn.h"
#include "libsimple/strtoint.h"
#include "libsimple/search.h"
+#include "libsimple/random.h"
/**
diff --git a/libsimple/random.h b/libsimple/random.h
new file mode 100644
index 0000000..3c09d7a
--- /dev/null
+++ b/libsimple/random.h
@@ -0,0 +1,22 @@
+/* See LICENSE file for copyright and license details. */
+
+
+/**
+ * Creates a pseudo-random seed
+ *
+ * @return The pseudo-random seed
+ */
+LIBSIMPLE_GCC_ONLY__(__attribute__((__warn_unused_result__)))
+unsigned int libsimple_generate_seed(void); /* TODO add man page */
+
+
+/**
+ * Wrapper for srand(3) that creates a pseudo-random
+ * seed with which it seeds the pseudo-random number
+ * generator
+ */
+inline void
+libsimple_srand(void) /* TODO add man page */
+{
+ srand(libsimple_generate_seed());
+}
diff --git a/srand.c b/srand.c
new file mode 100644
index 0000000..e1648cb
--- /dev/null
+++ b/srand.c
@@ -0,0 +1,18 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+extern inline void libsimple_srand(void); /* TODO add test */
+
+
+#else
+#include "test.h"
+
+int
+main(void)
+{
+ return 0;
+}
+
+#endif