pam-krb5: Import/add pam-krb5 from eyeire.orgvendor/pam-krb5/4.11vendor/pam-krb5

From https://www.eyrie.org/~eagle/software/pam-krb5/:

pam-krb5 provides a Kerberos PAM module that supports authentication,
user ticket cache handling, simple authorization (via .k5login or
checking Kerberos principals against local usernames), and password
changing. It can be configured through either options in the PAM
configuration itself or through entries in the system krb5.conf file,
and it tries to work around PAM implementation flaws in commonly-used
PAM-enabled applications such as OpenSSH and xdm. It supports both
PKINIT and FAST to the extent that the underlying Kerberos libraries
support these features.

The reason for this import is to provide an MIT KRB5 compatible
pam_krb5 PAM module. The existing pam_krb5 in FreeBS only works
with Heimdal.

Sponsored by:	The FreeBSD Foundation

1 files changed, 1029 insertions, 0 deletions

diff --git a/tests/tap/basic.c b/tests/tap/basic.c
new file mode 100644
index 000000000000..b5f42d0211a4
--- /dev/null
+++ b/tests/tap/basic.c
@@ -0,0 +1,1029 @@
+/*
+ * Some utility routines for writing tests.
+ *
+ * Here are a variety of utility routines for writing tests compatible with
+ * the TAP protocol.  All routines of the form ok() or is*() take a test
+ * number and some number of appropriate arguments, check to be sure the
+ * results match the expected output using the arguments, and print out
+ * something appropriate for that test number.  Other utility routines help in
+ * constructing more complex tests, skipping tests, reporting errors, setting
+ * up the TAP output format, or finding things in the test environment.
+ *
+ * This file is part of C TAP Harness.  The current version plus supporting
+ * documentation is at <https://www.eyrie.org/~eagle/software/c-tap-harness/>.
+ *
+ * Written by Russ Allbery <eagle@eyrie.org>
+ * Copyright 2009-2019 Russ Allbery <eagle@eyrie.org>
+ * Copyright 2001-2002, 2004-2008, 2011-2014
+ *     The Board of Trustees of the Leland Stanford Junior University
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#ifdef _WIN32
+#    include <direct.h>
+#else
+#    include <sys/stat.h>
+#endif
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <tests/tap/basic.h>
+
+/* Windows provides mkdir and rmdir under different names. */
+#ifdef _WIN32
+#    define mkdir(p, m) _mkdir(p)
+#    define rmdir(p)    _rmdir(p)
+#endif
+
+/*
+ * The test count.  Always contains the number that will be used for the next
+ * test status.  This is exported to callers of the library.
+ */
+unsigned long testnum = 1;
+
+/*
+ * Status information stored so that we can give a test summary at the end of
+ * the test case.  We store the planned final test and the count of failures.
+ * We can get the highest test count from testnum.
+ */
+static unsigned long _planned = 0;
+static unsigned long _failed = 0;
+
+/*
+ * Store the PID of the process that called plan() and only summarize
+ * results when that process exits, so as to not misreport results in forked
+ * processes.
+ */
+static pid_t _process = 0;
+
+/*
+ * If true, we're doing lazy planning and will print out the plan based on the
+ * last test number at the end of testing.
+ */
+static int _lazy = 0;
+
+/*
+ * If true, the test was aborted by calling bail().  Currently, this is only
+ * used to ensure that we pass a false value to any cleanup functions even if
+ * all tests to that point have passed.
+ */
+static int _aborted = 0;
+
+/*
+ * Registered cleanup functions.  These are stored as a linked list and run in
+ * registered order by finish when the test program exits.  Each function is
+ * passed a boolean value indicating whether all tests were successful.
+ */
+struct cleanup_func {
+    test_cleanup_func func;
+    test_cleanup_func_with_data func_with_data;
+    void *data;
+    struct cleanup_func *next;
+};
+static struct cleanup_func *cleanup_funcs = NULL;
+
+/*
+ * Registered diag files.  Any output found in these files will be printed out
+ * as if it were passed to diag() before any other output we do.  This allows
+ * background processes to log to a file and have that output interleaved with
+ * the test output.
+ */
+struct diag_file {
+    char *name;
+    FILE *file;
+    char *buffer;
+    size_t bufsize;
+    struct diag_file *next;
+};
+static struct diag_file *diag_files = NULL;
+
+/*
+ * Print a specified prefix and then the test description.  Handles turning
+ * the argument list into a va_args structure suitable for passing to
+ * print_desc, which has to be done in a macro.  Assumes that format is the
+ * argument immediately before the variadic arguments.
+ */
+#define PRINT_DESC(prefix, format)  \
+    do {                            \
+        if (format != NULL) {       \
+            va_list args;           \
+            printf("%s", prefix);   \
+            va_start(args, format); \
+            vprintf(format, args);  \
+            va_end(args);           \
+        }                           \
+    } while (0)
+
+
+/*
+ * Form a new string by concatenating multiple strings.  The arguments must be
+ * terminated by (const char *) 0.
+ *
+ * This function only exists because we can't assume asprintf.  We can't
+ * simulate asprintf with snprintf because we're only assuming SUSv3, which
+ * does not require that snprintf with a NULL buffer return the required
+ * length.  When those constraints are relaxed, this should be ripped out and
+ * replaced with asprintf or a more trivial replacement with snprintf.
+ */
+static char *
+concat(const char *first, ...)
+{
+    va_list args;
+    char *result;
+    const char *string;
+    size_t offset;
+    size_t length = 0;
+
+    /*
+     * Find the total memory required.  Ensure we don't overflow length.  See
+     * the comment for breallocarray for why we're using UINT_MAX here.
+     */
+    va_start(args, first);
+    for (string = first; string != NULL; string = va_arg(args, const char *)) {
+        if (length >= UINT_MAX - strlen(string))
+            bail("strings too long in concat");
+        length += strlen(string);
+    }
+    va_end(args);
+    length++;
+
+    /* Create the string. */
+    result = bcalloc_type(length, char);
+    va_start(args, first);
+    offset = 0;
+    for (string = first; string != NULL; string = va_arg(args, const char *)) {
+        memcpy(result + offset, string, strlen(string));
+        offset += strlen(string);
+    }
+    va_end(args);
+    result[offset] = '\0';
+    return result;
+}
+
+
+/*
+ * Helper function for check_diag_files to handle a single line in a diag
+ * file.
+ *
+ * The general scheme here used is as follows: read one line of output.  If we
+ * get NULL, check for an error.  If there was one, bail out of the test
+ * program; otherwise, return, and the enclosing loop will check for EOF.
+ *
+ * If we get some data, see if it ends in a newline.  If it doesn't end in a
+ * newline, we have one of two cases: our buffer isn't large enough, in which
+ * case we resize it and try again, or we have incomplete data in the file, in
+ * which case we rewind the file and will try again next time.
+ *
+ * Returns a boolean indicating whether the last line was incomplete.
+ */
+static int
+handle_diag_file_line(struct diag_file *file, fpos_t where)
+{
+    int size;
+    size_t length;
+
+    /* Read the next line from the file. */
+    size = file->bufsize > INT_MAX ? INT_MAX : (int) file->bufsize;
+    if (fgets(file->buffer, size, file->file) == NULL) {
+        if (ferror(file->file))
+            sysbail("cannot read from %s", file->name);
+        return 0;
+    }
+
+    /*
+     * See if the line ends in a newline.  If not, see which error case we
+     * have.
+     */
+    length = strlen(file->buffer);
+    if (file->buffer[length - 1] != '\n') {
+        int incomplete = 0;
+
+        /* Check whether we ran out of buffer space and resize if so. */
+        if (length < file->bufsize - 1)
+            incomplete = 1;
+        else {
+            file->bufsize += BUFSIZ;
+            file->buffer =
+                breallocarray_type(file->buffer, file->bufsize, char);
+        }
+
+        /*
+         * On either incomplete lines or too small of a buffer, rewind
+         * and read the file again (on the next pass, if incomplete).
+         * It's simpler than trying to double-buffer the file.
+         */
+        if (fsetpos(file->file, &where) < 0)
+            sysbail("cannot set position in %s", file->name);
+        return incomplete;
+    }
+
+    /* We saw a complete line.  Print it out. */
+    printf("# %s", file->buffer);
+    return 0;
+}
+
+
+/*
+ * Check all registered diag_files for any output.  We only print out the
+ * output if we see a complete line; otherwise, we wait for the next newline.
+ */
+static void
+check_diag_files(void)
+{
+    struct diag_file *file;
+    fpos_t where;
+    int incomplete;
+
+    /*
+     * Walk through each file and read each line of output available.
+     */
+    for (file = diag_files; file != NULL; file = file->next) {
+        clearerr(file->file);
+
+        /* Store the current position in case we have to rewind. */
+        if (fgetpos(file->file, &where) < 0)
+            sysbail("cannot get position in %s", file->name);
+
+        /* Continue until we get EOF or an incomplete line of data. */
+        incomplete = 0;
+        while (!feof(file->file) && !incomplete) {
+            incomplete = handle_diag_file_line(file, where);
+        }
+    }
+}
+
+
+/*
+ * Our exit handler.  Called on completion of the test to report a summary of
+ * results provided we're still in the original process.  This also handles
+ * printing out the plan if we used plan_lazy(), although that's suppressed if
+ * we never ran a test (due to an early bail, for example), and running any
+ * registered cleanup functions.
+ */
+static void
+finish(void)
+{
+    int success, primary;
+    struct cleanup_func *current;
+    unsigned long highest = testnum - 1;
+    struct diag_file *file, *tmp;
+
+    /* Check for pending diag_file output. */
+    check_diag_files();
+
+    /* Free the diag_files. */
+    file = diag_files;
+    while (file != NULL) {
+        tmp = file;
+        file = file->next;
+        fclose(tmp->file);
+        free(tmp->name);
+        free(tmp->buffer);
+        free(tmp);
+    }
+    diag_files = NULL;
+
+    /*
+     * Determine whether all tests were successful, which is needed before
+     * calling cleanup functions since we pass that fact to the functions.
+     */
+    if (_planned == 0 && _lazy)
+        _planned = highest;
+    success = (!_aborted && _planned == highest && _failed == 0);
+
+    /*
+     * If there are any registered cleanup functions, we run those first.  We
+     * always run them, even if we didn't run a test.  Don't do anything
+     * except free the diag_files and call cleanup functions if we aren't the
+     * primary process (the process in which plan or plan_lazy was called),
+     * and tell the cleanup functions that fact.
+     */
+    primary = (_process == 0 || getpid() == _process);
+    while (cleanup_funcs != NULL) {
+        if (cleanup_funcs->func_with_data) {
+            void *data = cleanup_funcs->data;
+
+            cleanup_funcs->func_with_data(success, primary, data);
+        } else {
+            cleanup_funcs->func(success, primary);
+        }
+        current = cleanup_funcs;
+        cleanup_funcs = cleanup_funcs->next;
+        free(current);
+    }
+    if (!primary)
+        return;
+
+    /* Don't do anything further if we never planned a test. */
+    if (_planned == 0)
+        return;
+
+    /* If we're aborting due to bail, don't print summaries. */
+    if (_aborted)
+        return;
+
+    /* Print out the lazy plan if needed. */
+    fflush(stderr);
+    if (_lazy && _planned > 0)
+        printf("1..%lu\n", _planned);
+
+    /* Print out a summary of the results. */
+    if (_planned > highest)
+        diag("Looks like you planned %lu test%s but only ran %lu", _planned,
+             (_planned > 1 ? "s" : ""), highest);
+    else if (_planned < highest)
+        diag("Looks like you planned %lu test%s but ran %lu extra", _planned,
+             (_planned > 1 ? "s" : ""), highest - _planned);
+    else if (_failed > 0)
+        diag("Looks like you failed %lu test%s of %lu", _failed,
+             (_failed > 1 ? "s" : ""), _planned);
+    else if (_planned != 1)
+        diag("All %lu tests successful or skipped", _planned);
+    else
+        diag("%lu test successful or skipped", _planned);
+}
+
+
+/*
+ * Initialize things.  Turns on line buffering on stdout and then prints out
+ * the number of tests in the test suite.  We intentionally don't check for
+ * pending diag_file output here, since it should really come after the plan.
+ */
+void
+plan(unsigned long count)
+{
+    if (setvbuf(stdout, NULL, _IOLBF, BUFSIZ) != 0)
+        sysdiag("cannot set stdout to line buffered");
+    fflush(stderr);
+    printf("1..%lu\n", count);
+    testnum = 1;
+    _planned = count;
+    _process = getpid();
+    if (atexit(finish) != 0) {
+        sysdiag("cannot register exit handler");
+        diag("cleanups will not be run");
+    }
+}
+
+
+/*
+ * Initialize things for lazy planning, where we'll automatically print out a
+ * plan at the end of the program.  Turns on line buffering on stdout as well.
+ */
+void
+plan_lazy(void)
+{
+    if (setvbuf(stdout, NULL, _IOLBF, BUFSIZ) != 0)
+        sysdiag("cannot set stdout to line buffered");
+    testnum = 1;
+    _process = getpid();
+    _lazy = 1;
+    if (atexit(finish) != 0)
+        sysbail("cannot register exit handler to display plan");
+}
+
+
+/*
+ * Skip the entire test suite and exits.  Should be called instead of plan(),
+ * not after it, since it prints out a special plan line.  Ignore diag_file
+ * output here, since it's not clear if it's allowed before the plan.
+ */
+void
+skip_all(const char *format, ...)
+{
+    fflush(stderr);
+    printf("1..0 # skip");
+    PRINT_DESC(" ", format);
+    putchar('\n');
+    exit(0);
+}
+
+
+/*
+ * Takes a boolean success value and assumes the test passes if that value
+ * is true and fails if that value is false.
+ */
+int
+ok(int success, const char *format, ...)
+{
+    fflush(stderr);
+    check_diag_files();
+    printf("%sok %lu", success ? "" : "not ", testnum++);
+    if (!success)
+        _failed++;
+    PRINT_DESC(" - ", format);
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Same as ok(), but takes the format arguments as a va_list.
+ */
+int
+okv(int success, const char *format, va_list args)
+{
+    fflush(stderr);
+    check_diag_files();
+    printf("%sok %lu", success ? "" : "not ", testnum++);
+    if (!success)
+        _failed++;
+    if (format != NULL) {
+        printf(" - ");
+        vprintf(format, args);
+    }
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Skip a test.
+ */
+void
+skip(const char *reason, ...)
+{
+    fflush(stderr);
+    check_diag_files();
+    printf("ok %lu # skip", testnum++);
+    PRINT_DESC(" ", reason);
+    putchar('\n');
+}
+
+
+/*
+ * Report the same status on the next count tests.
+ */
+int
+ok_block(unsigned long count, int success, const char *format, ...)
+{
+    unsigned long i;
+
+    fflush(stderr);
+    check_diag_files();
+    for (i = 0; i < count; i++) {
+        printf("%sok %lu", success ? "" : "not ", testnum++);
+        if (!success)
+            _failed++;
+        PRINT_DESC(" - ", format);
+        putchar('\n');
+    }
+    return success;
+}
+
+
+/*
+ * Skip the next count tests.
+ */
+void
+skip_block(unsigned long count, const char *reason, ...)
+{
+    unsigned long i;
+
+    fflush(stderr);
+    check_diag_files();
+    for (i = 0; i < count; i++) {
+        printf("ok %lu # skip", testnum++);
+        PRINT_DESC(" ", reason);
+        putchar('\n');
+    }
+}
+
+
+/*
+ * Takes two boolean values and requires the truth value of both match.
+ */
+int
+is_bool(int left, int right, const char *format, ...)
+{
+    int success;
+
+    fflush(stderr);
+    check_diag_files();
+    success = (!!left == !!right);
+    if (success)
+        printf("ok %lu", testnum++);
+    else {
+        diag(" left: %s", !!left ? "true" : "false");
+        diag("right: %s", !!right ? "true" : "false");
+        printf("not ok %lu", testnum++);
+        _failed++;
+    }
+    PRINT_DESC(" - ", format);
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Takes two integer values and requires they match.
+ */
+int
+is_int(long left, long right, const char *format, ...)
+{
+    int success;
+
+    fflush(stderr);
+    check_diag_files();
+    success = (left == right);
+    if (success)
+        printf("ok %lu", testnum++);
+    else {
+        diag(" left: %ld", left);
+        diag("right: %ld", right);
+        printf("not ok %lu", testnum++);
+        _failed++;
+    }
+    PRINT_DESC(" - ", format);
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Takes two strings and requires they match (using strcmp).  NULL arguments
+ * are permitted and handled correctly.
+ */
+int
+is_string(const char *left, const char *right, const char *format, ...)
+{
+    int success;
+
+    fflush(stderr);
+    check_diag_files();
+
+    /* Compare the strings, being careful of NULL. */
+    if (left == NULL)
+        success = (right == NULL);
+    else if (right == NULL)
+        success = 0;
+    else
+        success = (strcmp(left, right) == 0);
+
+    /* Report the results. */
+    if (success)
+        printf("ok %lu", testnum++);
+    else {
+        diag(" left: %s", left == NULL ? "(null)" : left);
+        diag("right: %s", right == NULL ? "(null)" : right);
+        printf("not ok %lu", testnum++);
+        _failed++;
+    }
+    PRINT_DESC(" - ", format);
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Takes two unsigned longs and requires they match.  On failure, reports them
+ * in hex.
+ */
+int
+is_hex(unsigned long left, unsigned long right, const char *format, ...)
+{
+    int success;
+
+    fflush(stderr);
+    check_diag_files();
+    success = (left == right);
+    if (success)
+        printf("ok %lu", testnum++);
+    else {
+        diag(" left: %lx", (unsigned long) left);
+        diag("right: %lx", (unsigned long) right);
+        printf("not ok %lu", testnum++);
+        _failed++;
+    }
+    PRINT_DESC(" - ", format);
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Takes pointers to a regions of memory and requires that len bytes from each
+ * match.  Otherwise reports any bytes which didn't match.
+ */
+int
+is_blob(const void *left, const void *right, size_t len, const char *format,
+        ...)
+{
+    int success;
+    size_t i;
+
+    fflush(stderr);
+    check_diag_files();
+    success = (memcmp(left, right, len) == 0);
+    if (success)
+        printf("ok %lu", testnum++);
+    else {
+        const unsigned char *left_c = (const unsigned char *) left;
+        const unsigned char *right_c = (const unsigned char *) right;
+
+        for (i = 0; i < len; i++) {
+            if (left_c[i] != right_c[i])
+                diag("offset %lu: left %02x, right %02x", (unsigned long) i,
+                     left_c[i], right_c[i]);
+        }
+        printf("not ok %lu", testnum++);
+        _failed++;
+    }
+    PRINT_DESC(" - ", format);
+    putchar('\n');
+    return success;
+}
+
+
+/*
+ * Bail out with an error.
+ */
+void
+bail(const char *format, ...)
+{
+    va_list args;
+
+    _aborted = 1;
+    fflush(stderr);
+    check_diag_files();
+    fflush(stdout);
+    printf("Bail out! ");
+    va_start(args, format);
+    vprintf(format, args);
+    va_end(args);
+    printf("\n");
+    exit(255);
+}
+
+
+/*
+ * Bail out with an error, appending strerror(errno).
+ */
+void
+sysbail(const char *format, ...)
+{
+    va_list args;
+    int oerrno = errno;
+
+    _aborted = 1;
+    fflush(stderr);
+    check_diag_files();
+    fflush(stdout);
+    printf("Bail out! ");
+    va_start(args, format);
+    vprintf(format, args);
+    va_end(args);
+    printf(": %s\n", strerror(oerrno));
+    exit(255);
+}
+
+
+/*
+ * Report a diagnostic to stderr.  Always returns 1 to allow embedding in
+ * compound statements.
+ */
+int
+diag(const char *format, ...)
+{
+    va_list args;
+
+    fflush(stderr);
+    check_diag_files();
+    fflush(stdout);
+    printf("# ");
+    va_start(args, format);
+    vprintf(format, args);
+    va_end(args);
+    printf("\n");
+    return 1;
+}
+
+
+/*
+ * Report a diagnostic to stderr, appending strerror(errno).  Always returns 1
+ * to allow embedding in compound statements.
+ */
+int
+sysdiag(const char *format, ...)
+{
+    va_list args;
+    int oerrno = errno;
+
+    fflush(stderr);
+    check_diag_files();
+    fflush(stdout);
+    printf("# ");
+    va_start(args, format);
+    vprintf(format, args);
+    va_end(args);
+    printf(": %s\n", strerror(oerrno));
+    return 1;
+}
+
+
+/*
+ * Register a new file for diag_file processing.
+ */
+void
+diag_file_add(const char *name)
+{
+    struct diag_file *file, *prev;
+
+    file = bcalloc_type(1, struct diag_file);
+    file->name = bstrdup(name);
+    file->file = fopen(file->name, "r");
+    if (file->file == NULL)
+        sysbail("cannot open %s", name);
+    file->buffer = bcalloc_type(BUFSIZ, char);
+    file->bufsize = BUFSIZ;
+    if (diag_files == NULL)
+        diag_files = file;
+    else {
+        for (prev = diag_files; prev->next != NULL; prev = prev->next)
+            ;
+        prev->next = file;
+    }
+}
+
+
+/*
+ * Remove a file from diag_file processing.  If the file is not found, do
+ * nothing, since there are some situations where it can be removed twice
+ * (such as if it's removed from a cleanup function, since cleanup functions
+ * are called after freeing all the diag_files).
+ */
+void
+diag_file_remove(const char *name)
+{
+    struct diag_file *file;
+    struct diag_file **prev = &diag_files;
+
+    for (file = diag_files; file != NULL; file = file->next) {
+        if (strcmp(file->name, name) == 0) {
+            *prev = file->next;
+            fclose(file->file);
+            free(file->name);
+            free(file->buffer);
+            free(file);
+            return;
+        }
+        prev = &file->next;
+    }
+}
+
+
+/*
+ * Allocate cleared memory, reporting a fatal error with bail on failure.
+ */
+void *
+bcalloc(size_t n, size_t size)
+{
+    void *p;
+
+    p = calloc(n, size);
+    if (p == NULL)
+        sysbail("failed to calloc %lu", (unsigned long) (n * size));
+    return p;
+}
+
+
+/*
+ * Allocate memory, reporting a fatal error with bail on failure.
+ */
+void *
+bmalloc(size_t size)
+{
+    void *p;
+
+    p = malloc(size);
+    if (p == NULL)
+        sysbail("failed to malloc %lu", (unsigned long) size);
+    return p;
+}
+
+
+/*
+ * Reallocate memory, reporting a fatal error with bail on failure.
+ */
+void *
+brealloc(void *p, size_t size)
+{
+    p = realloc(p, size);
+    if (p == NULL)
+        sysbail("failed to realloc %lu bytes", (unsigned long) size);
+    return p;
+}
+
+
+/*
+ * The same as brealloc, but determine the size by multiplying an element
+ * count by a size, similar to calloc.  The multiplication is checked for
+ * integer overflow.
+ *
+ * We should technically use SIZE_MAX here for the overflow check, but
+ * SIZE_MAX is C99 and we're only assuming C89 + SUSv3, which does not
+ * guarantee that it exists.  They do guarantee that UINT_MAX exists, and we
+ * can assume that UINT_MAX <= SIZE_MAX.
+ *
+ * (In theory, C89 and C99 permit size_t to be smaller than unsigned int, but
+ * I disbelieve in the existence of such systems and they will have to cope
+ * without overflow checks.)
+ */
+void *
+breallocarray(void *p, size_t n, size_t size)
+{
+    if (n > 0 && UINT_MAX / n <= size)
+        bail("reallocarray too large");
+    if (n == 0)
+        n = 1;
+    p = realloc(p, n * size);
+    if (p == NULL)
+        sysbail("failed to realloc %lu bytes", (unsigned long) (n * size));
+    return p;
+}
+
+
+/*
+ * Copy a string, reporting a fatal error with bail on failure.
+ */
+char *
+bstrdup(const char *s)
+{
+    char *p;
+    size_t len;
+
+    len = strlen(s) + 1;
+    p = (char *) malloc(len);
+    if (p == NULL)
+        sysbail("failed to strdup %lu bytes", (unsigned long) len);
+    memcpy(p, s, len);
+    return p;
+}
+
+
+/*
+ * Copy up to n characters of a string, reporting a fatal error with bail on
+ * failure.  Don't use the system strndup function, since it may not exist and
+ * the TAP library doesn't assume any portability support.
+ */
+char *
+bstrndup(const char *s, size_t n)
+{
+    const char *p;
+    char *copy;
+    size_t length;
+
+    /* Don't assume that the source string is nul-terminated. */
+    for (p = s; (size_t)(p - s) < n && *p != '\0'; p++)
+        ;
+    length = (size_t)(p - s);
+    copy = (char *) malloc(length + 1);
+    if (copy == NULL)
+        sysbail("failed to strndup %lu bytes", (unsigned long) length);
+    memcpy(copy, s, length);
+    copy[length] = '\0';
+    return copy;
+}
+
+
+/*
+ * Locate a test file.  Given the partial path to a file, look under
+ * C_TAP_BUILD and then C_TAP_SOURCE for the file and return the full path to
+ * the file.  Returns NULL if the file doesn't exist.  A non-NULL return
+ * should be freed with test_file_path_free().
+ */
+char *
+test_file_path(const char *file)
+{
+    char *base;
+    char *path = NULL;
+    const char *envs[] = {"C_TAP_BUILD", "C_TAP_SOURCE", NULL};
+    int i;
+
+    for (i = 0; envs[i] != NULL; i++) {
+        base = getenv(envs[i]);
+        if (base == NULL)
+            continue;
+        path = concat(base, "/", file, (const char *) 0);
+        if (access(path, R_OK) == 0)
+            break;
+        free(path);
+        path = NULL;
+    }
+    return path;
+}
+
+
+/*
+ * Free a path returned from test_file_path().  This function exists primarily
+ * for Windows, where memory must be freed from the same library domain that
+ * it was allocated from.
+ */
+void
+test_file_path_free(char *path)
+{
+    free(path);
+}
+
+
+/*
+ * Create a temporary directory, tmp, under C_TAP_BUILD if set and the current
+ * directory if it does not.  Returns the path to the temporary directory in
+ * newly allocated memory, and calls bail on any failure.  The return value
+ * should be freed with test_tmpdir_free.
+ *
+ * This function uses sprintf because it attempts to be independent of all
+ * other portability layers.  The use immediately after a memory allocation
+ * should be safe without using snprintf or strlcpy/strlcat.
+ */
+char *
+test_tmpdir(void)
+{
+    const char *build;
+    char *path = NULL;
+
+    build = getenv("C_TAP_BUILD");
+    if (build == NULL)
+        build = ".";
+    path = concat(build, "/tmp", (const char *) 0);
+    if (access(path, X_OK) < 0)
+        if (mkdir(path, 0777) < 0)
+            sysbail("error creating temporary directory %s", path);
+    return path;
+}
+
+
+/*
+ * Free a path returned from test_tmpdir() and attempt to remove the
+ * directory.  If we can't delete the directory, don't worry; something else
+ * that hasn't yet cleaned up may still be using it.
+ */
+void
+test_tmpdir_free(char *path)
+{
+    if (path != NULL)
+        rmdir(path);
+    free(path);
+}
+
+static void
+register_cleanup(test_cleanup_func func,
+                 test_cleanup_func_with_data func_with_data, void *data)
+{
+    struct cleanup_func *cleanup, **last;
+
+    cleanup = bcalloc_type(1, struct cleanup_func);
+    cleanup->func = func;
+    cleanup->func_with_data = func_with_data;
+    cleanup->data = data;
+    cleanup->next = NULL;
+    last = &cleanup_funcs;
+    while (*last != NULL)
+        last = &(*last)->next;
+    *last = cleanup;
+}
+
+/*
+ * Register a cleanup function that is called when testing ends.  All such
+ * registered functions will be run by finish.
+ */
+void
+test_cleanup_register(test_cleanup_func func)
+{
+    register_cleanup(func, NULL, NULL);
+}
+
+/*
+ * Same as above, but also allows an opaque pointer to be passed to the cleanup
+ * function.
+ */
+void
+test_cleanup_register_with_data(test_cleanup_func_with_data func, void *data)
+{
+    register_cleanup(NULL, func, data);
+}