[PATCH 1/2] simple random data generator for tests
From: Nicolas Pitre <hidden>
Date: 2016-06-15 22:43:04
Subsystem:
kernel build + files below scripts/ (unless maintained elsewhere), the rest · Maintainers:
Nathan Chancellor, Nicolas Schier, Linus Torvalds
Reliance on /dev/urandom produces test vectors that are, well, random. This can create problems impossible to track down when the data is different from one test invokation to another. The goal is not to have random data to test, but rather to have a convenient way to create sets of large files with non compressible and non deltifiable data in a reproducible way. Signed-off-by: Nicolas Pitre <redacted> --- Makefile | 7 +++++-- test-genrandom.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+), 2 deletions(-) create mode 100644 test-genrandom.c
diff --git a/Makefile b/Makefile
index a77d31d..bd0ba95 100644
--- a/Makefile
+++ b/Makefile@@ -932,7 +932,7 @@ endif export NO_SVN_TESTS -test: all test-chmtime$X +test: all test-chmtime$X test-genrandom$X $(MAKE) -C t/ all test-date$X: test-date.c date.o ctype.o
@@ -953,6 +953,9 @@ test-match-trees$X: test-match-trees.o $(GITLIBS) test-chmtime$X: test-chmtime.c $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $< +test-genrandom$X: test-genrandom.c + $(CC) $(ALL_CFLAGS) -o $@ $(ALL_LDFLAGS) $< + check-sha1:: test-sha1$X ./test-sha1.sh
@@ -1041,7 +1044,7 @@ dist-doc: clean: rm -f *.o mozilla-sha1/*.o arm/*.o ppc/*.o compat/*.o xdiff/*.o \ - test-chmtime$X $(LIB_FILE) $(XDIFF_LIB) + test-chmtime$X test-genrandom$X $(LIB_FILE) $(XDIFF_LIB) rm -f $(ALL_PROGRAMS) $(BUILT_INS) git$X rm -f *.spec *.pyc *.pyo */*.pyc */*.pyo common-cmds.h TAGS tags rm -rf autom4te.cache
diff --git a/test-genrandom.c b/test-genrandom.c
new file mode 100644
index 0000000..6cc4650
--- /dev/null
+++ b/test-genrandom.c@@ -0,0 +1,34 @@ +/* + * Simple random data generator used to create reproducible test files. + * This is inspired from POSIX.1-2001 implementation example for rand(). + * Copyright (C) 2007 by Nicolas Pitre, licensed under the GPL version 2. + */ + +#include <stdio.h> +#include <stdlib.h> + +int main(int argc, char *argv[]) +{ + unsigned long count, next = 0; + unsigned char *c; + + if (argc < 2 || argc > 3) { + fprintf( stderr, "Usage: %s <seed_string> [<size>]", argv[0]); + return 1; + } + + c = (unsigned char *) argv[1]; + do { + next = next * 11 + *c; + } while (*c++); + + count = (argc == 3) ? strtoul(argv[2], NULL, 0) : -1L; + + while (count--) { + next = next * 1103515245 + 12345; + if (putchar((next >> 16) & 0xff) == EOF) + return -1; + } + + return 0; +}
--
1.5.1.777.gd14d3-dirty