test: fetch prng seed from environment variable

Tests that require PRNG are by default seeded from `/dev/urandom`.
However, the user should be able to override with a given seed
to reproduce a failing test.

Instead of messing with command-line arguments, a cleaner approach
is to fetch the seed from an environment variable.

Makefile.am

@@ -8,5 +8,3 @@
 
 ACLOCAL_AMFLAGS = -I m4
 SUBDIRS         = doc src tests
-
-pkgconfig_DATA = bookmarkfs_util.pc

configure.ac

@@ -9,7 +9,7 @@ dnl
 
 AC_PREREQ([2.70])
 AC_INIT([bookmarkfs], [0.1.2], [bug-bookmarkfs@nongnu.org])
-AC_CONFIG_SRCDIR([bookmarkfs_util.pc.in])
+AC_CONFIG_SRCDIR([src/bookmarkfs_util.pc.in])
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_TESTDIR([tests])
@@ -175,8 +175,7 @@ AC_DEFINE([BUILDING_BOOKMARKFS], [1], [Define to 1 if building BookmarkFS.])
 AC_CONFIG_FILES([
     Makefile
     doc/Makefile
-    src/Makefile
+    src/Makefile src/bookmarkfs_util.pc
     tests/Makefile tests/atlocal
-    bookmarkfs_util.pc
 ])
 AC_OUTPUT

src/Makefile.am

@@ -13,6 +13,7 @@ noinst_HEADERS     = backend_util.h db.h defs.h frontend_util.h fs_ops.h  \
                      xattr.h xstd.h
 lib_LTLIBRARIES    =
 pkglib_LTLIBRARIES =
+pkgconfig_DATA     = bookmarkfs_util.pc
 
 BASE_CPPFLAGS_ =
 if NO_FILE_NAME

src/prng.c

@@ -29,6 +29,7 @@
 #include "prng.h"
 
 #include <errno.h>
+#include <inttypes.h>
 #include <string.h>
 
 #include <sys/random.h>
@@ -89,5 +90,8 @@ prng_seed (
     // as many bytes as requested.
     // This is guaranteed on both Linux and FreeBSD.
     debug_assert(nbytes == sizeof(state));
+    debug_printf("prng seed: "
+            "%016" PRIx64 "%016" PRIx64 "%016" PRIx64 "%016" PRIx64,
+            state[0], state[1], state[2], state[3]);
     return 0;
 }

tests/check_fs_dents.c

@@ -239,18 +239,13 @@ check_fs_dents (
     int   argc,
     char *argv[]
 ) {
-    char const *seed = NULL;
     int n = -1;
 
-    OPT_START(argc, argv, "n:s:")
+    OPT_START(argc, argv, "n:")
     OPT_OPT('n') {
         n = atoi(optarg);
         break;
     }
-    OPT_OPT('s') {
-        seed = optarg;
-        break;
-    }
     OPT_END
 
     if (n <= 0) {
@@ -263,7 +258,7 @@ check_fs_dents (
     }
     char const *path = argv[0];
 
-    if (0 != prng_seed_from_hex(seed)) {
+    if (0 != prng_seed_from_env()) {
         return -1;
     }
     int dirfd = open(path, O_RDONLY | O_DIRECTORY);

tests/check_fs_regrw.c

@@ -167,18 +167,13 @@ check_fs_regrw (
     int   argc,
     char *argv[]
 ) {
-    char const *seed = NULL;
     int file_max = -1;
 
-    OPT_START(argc, argv, "n:s:")
+    OPT_START(argc, argv, "n:")
     OPT_OPT('n') {
         file_max = atoi(optarg);
         break;
     }
-    OPT_OPT('s') {
-        seed = optarg;
-        break;
-    }
     OPT_END
 
     if (file_max <= 0 || file_max % sizeof(uint64_t) != 0) {
@@ -191,7 +186,7 @@ check_fs_regrw (
     }
     char const *path = argv[0];
 
-    if (0 != prng_seed_from_hex(seed)) {
+    if (0 != prng_seed_from_env()) {
         return -1;
     }
     return do_check_fs_regrw(path, file_max);

tests/check_fs_times.c

@@ -160,18 +160,13 @@ check_fs_times (
     int   argc,
     char *argv[]
 ) {
-    char const *seed = NULL;
     int rounds = -1;
 
-    OPT_START(argc, argv, "r:s:")
+    OPT_START(argc, argv, "r:")
     OPT_OPT('r') {
         rounds = atoi(optarg);
         break;
     }
-    OPT_OPT('s') {
-        seed = optarg;
-        break;
-    }
     OPT_END
 
     if (rounds < 0) {
@@ -184,7 +179,7 @@ check_fs_times (
     }
     char const *path = argv[0];
 
-    if (0 != prng_seed_from_hex(seed)) {
+    if (0 != prng_seed_from_env()) {
         return -1;
     }
     int dirfd = open(path, O_RDONLY | O_DIRECTORY);

tests/check_hashmap.c

@@ -168,15 +168,10 @@ check_hashmap (
     int   argc,
     char *argv[]
 ) {
-    char const *seed = NULL;
     int size_exp = -1;
     int rounds   = -1;
 
-    OPT_START(argc, argv, "s:n:r:")
-    OPT_OPT('s') {
-        seed = optarg;
-        break;
-    }
+    OPT_START(argc, argv, "n:r:")
     OPT_OPT('n') {
         size_exp = atoi(optarg);
         break;
@@ -196,7 +191,7 @@ check_hashmap (
         return -1;
     }
 
-    if (0 != prng_seed_from_hex(seed)) {
+    if (0 != prng_seed_from_env()) {
         return -1;
     }
     return do_check_hashmap(1u << size_exp, rounds);

tests/check_lib.c

@@ -104,21 +104,16 @@ subcmd_prng (
     int   argc,
     char *argv[]
 ) {
-    char const *seed = NULL;
     int n = 0;
 
-    OPT_START(argc, argv, "s:n:")
-    OPT_OPT('s') {
-        seed = optarg;
-        break;
-    }
+    OPT_START(argc, argv, "n:")
     OPT_OPT('n') {
         n = atoi(optarg);
         break;
     }
     OPT_END
 
-    if (0 != prng_seed_from_hex(seed)) {
+    if (0 != prng_seed_from_env()) {
         return -1;
     }
     for (; n > 0; --n) {

tests/check_util.c

@@ -26,25 +26,25 @@
 
 #include <inttypes.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "prng.h"
 
 int
-prng_seed_from_hex (
-    char const *str
-) {
-    uint64_t buf[4], *seed = NULL;
+prng_seed_from_env (void)
+{
+    char const *seed_str = getenv("BOOKMARKFS_TEST_PRNG_SEED");
+    if (seed_str == NULL) {
+        return prng_seed(NULL);
+    }
 
-    if (str != NULL) {
-        int cnt = sscanf(str,
-                "%16" SCNx64 "%16" SCNx64 "%16" SCNx64 "%16" SCNx64,
-                &buf[0], &buf[1], &buf[2], &buf[3]);
-        if (cnt != 4) {
-            log_puts("bad prng seed");
-            return -1;
-        }
-        seed = buf;
-        log_printf("prng seed: '%s'", str);
+    uint64_t seed[4];
+    int cnt = sscanf(seed_str,
+            "%16" SCNx64 "%16" SCNx64 "%16" SCNx64 "%16" SCNx64,
+            &seed[0], &seed[1], &seed[2], &seed[3]);
+    if (cnt != 4) {
+        log_puts("bad prng seed");
+        return -1;
     }
     return prng_seed(seed);
 }

tests/check_util.h

@@ -72,8 +72,6 @@ check_watcher (
 );
 
 int
-prng_seed_from_hex (
-    char const *str
-);
+prng_seed_from_env (void);
 
 #endif  /* !defined(BOOKMARKFS_CHECK_UTIL_H_) */

tests/fs_dents.at

@@ -13,11 +13,10 @@ AT_KEYWORDS([fs dents])
 ATX_CHECK_FS_NEW_ANY(, , [
     ATX_RUN_REPEAT([8], [
         name=$(ath_fn_rand_u64_hex)
-        seed=$(ath_fn_prng_seed)
 
         mkdir $name
         ATX_RUN([
-            check-fs dents -n 1024 -s "$seed" $name
+            check-fs dents -n 1024 $name
         ])
     ])
 ])

tests/fs_regrw.at

@@ -12,10 +12,9 @@ AT_KEYWORDS([fs regrw])
 
 ATX_CHECK_FS_NEW_ANY([file_max=524288], , [
     name=$(ath_fn_rand_u64_hex)
-    seed=$(ath_fn_prng_seed)
 
     ATX_RUN([
-        check-fs regrw -n 524288 -s "$seed" $name
+        check-fs regrw -n 524288 $name
     ])
 ])
 

tests/fs_times.at

@@ -12,11 +12,10 @@ AT_KEYWORDS([fs times])
 
 ATX_CHECK_FS_NEW_ANY(, , [
     name=$(ath_fn_rand_u64_hex)
-    seed=$(ath_fn_prng_seed)
 
     mkdir $name
     ATX_RUN([
-        check-fs times -s "$seed" -r 512 $name
+        check-fs times -r 512 $name
     ])
 ])
 

tests/lib_hashmap.at

@@ -11,11 +11,6 @@ AT_SETUP([util lib: hashmap])
 AT_KEYWORDS([lib hashmap])
 
 ATX_CHECK_LIB([
-    seed="${CHECK_HASHMAP_PRNG_SEED}"
-    if test -z "$seed"; then
-        seed=$(ath_fn_prng_seed)
-    fi
-
     size="${CHECK_HASHMAP_DATA_SIZE}"
     if test -z "$size"; then
         # Requires at least 128 MiB of memory on a 64-bit platform.
@@ -28,7 +23,7 @@ ATX_CHECK_LIB([
     fi
 
     ATX_RUN([
-        check-util-lib hashmap -s "$seed" -n "$size" -r "$rounds"
+        check-util-lib hashmap -n "$size" -r "$rounds"
     ])
 ])
 

tests/lib_prng.at

@@ -15,11 +15,15 @@ AT_KEYWORDS([lib prng])
 # For reliable testing of PRNGs, see <https://prng.di.unimi.it/#quality>.
 ATX_CHECK_LIB([
     gen_num() {
-        check-util-lib prng -s$1 -n$2
+        env BOOKMARKFS_TEST_PRNG_SEED=$1 check-util-lib prng -n$2
     }
 
-    ATX_RUN_REPEAT([16], [
-        seed=$(ath_fn_prng_seed)
+    repeat=1
+    if test -z "$BOOKMARKFS_TEST_PRNG_SEED"; then
+        repeat=16
+    fi
+    ATX_RUN_REPEAT([$repeat], [
+        seed=$(check-util-lib prng -n4 | tr -d '\n')
         count=32
 
         num_1=$(gen_num $seed $count)

tests/testsuite.at

@@ -125,8 +125,9 @@ dnl  Check for a BookmarkFS filesystem.
 dnl
 m4_define([ATX_CHECK_FS], [
     ATX_CHECK_SIMPLE([
-        ATX_FEAT_PREREQ([bookmarkfs-mount], [backend-$1])
+        ATX_FEAT_PREREQ([bookmarkfs-mount])
         $5
+        ATX_FEAT_IF([backend-$1], , [exit])
         "$buildsrcdir/mount.bookmarkfs" -F  \
                 -o "backend=ATX_OPT_MODULE([backend_$1])"  \
                 -o "fsname=check-$1,no_sandbox,$2"  \
@@ -153,8 +154,9 @@ dnl  created with mkfs.bookmarkfs.
 dnl
 m4_define([ATX_CHECK_FS_NEW], [
     ATX_CHECK_FS([$1], [rw,$2], [bookmarks-$1], [$3], [
-        ATX_FEAT_PREREQ([bookmarkfs-mkfs], [backend-$1-write])
+        ATX_FEAT_PREREQ([bookmarkfs-mkfs])
         $4
+        ATX_FEAT_IF([backend-$1-write], , [exit])
         "$buildsrcdir/mkfs.bookmarkfs"  \
                 -o "backend=ATX_OPT_MODULE([backend_$1]),force"  \
                 "bookmarks-$1" || exit 1
@@ -197,15 +199,6 @@ AT_TEST_HELPER_FN([rand_base64], , , [
     echo $(head -c$1 /dev/urandom | base64 -w0)
 ])
 
-AT_TEST_HELPER_FN([prng_seed], , , [
-    seed_1=$(ath_fn_rand_u64_hex)
-    seed_2=$(ath_fn_rand_u64_hex)
-    seed_3=$(ath_fn_rand_u64_hex)
-    seed_4=$(ath_fn_rand_u64_hex)
-
-    echo $seed_1$seed_2$seed_3$seed_4
-])
-
 dnl  -- Test groups --
 
 AT_BANNER([The Utility Library])