libakstdlib/tests/test_format.c

/*
 * Formatted-output wrappers: aksl_printf / aksl_fprintf / aksl_snprintf and
 * their va_list forms.
 *
 * TODO.md section 1.3, now complete. Each happy path asserts both halves of the
 * contract -- the byte count handed back through *count and the text that
 * actually landed somewhere -- and every pointer argument is checked for its
 * NULL guard.
 *
 * Readback goes through plain libc rather than aksl_fread so that a failure here
 * points at the formatted-output wrapper under test and not at the stream
 * wrappers, which tests/test_stream.c covers.
 *
 * aksl_sprintf is gone (TODO.md 2.2.4) and aksl_snprintf takes its place, so the
 * destination-overflow case that could not previously be written is here: it is
 * AKERR_OUTOFBOUNDS, not the short success snprintf(3) would have reported.
 */

#include "aksl_capture.h"

#include <errno.h>

/* Read a whole file into buf and NUL-terminate. Returns bytes read, or -1. */
static long read_file(const char *path, char *buf, size_t n)
{
    FILE *fp = fopen(path, "r");
    size_t got = 0;

    if ( fp == NULL ) {
	return -1;
    }
    got = fread(buf, 1, n - 1, fp);
    buf[got] = '\0';
    if ( ferror(fp) ) {
	fclose(fp);
	return -1;
    }
    fclose(fp);
    return (long)got;
}

static int test_snprintf_writes_text_and_count(void)
{
    char buf[64];
    int count = -1;

    memset(buf, 0x00, sizeof(buf));
    AKSL_CHECK_OK(aksl_snprintf(&count, buf, sizeof(buf), "%s=%d", "x", 7));
    AKSL_CHECK(count == 3);
    AKSL_CHECK(strcmp(buf, "x=7") == 0);
    return 0;
}

static int test_snprintf_empty_format_writes_nothing(void)
{
    char buf[8] = { 'z', 'z', 'z', 'z', 'z', 'z', 'z', 'z' };
    int count = -1;

    AKSL_CHECK_OK(aksl_snprintf(&count, buf, sizeof(buf), "%s", ""));
    AKSL_CHECK(count == 0);
    AKSL_CHECK(buf[0] == '\0');
    return 0;
}

/*
 * The case that could not be written while the wrapper was aksl_sprintf: output
 * longer than the destination. snprintf(3) would truncate, NUL-terminate and
 * report the length it *would* have written, leaving the caller to notice; here
 * it is an error, and *count is 0 rather than the would-have-been length.
 */
static int test_snprintf_truncation_is_an_error(void)
{
    char buf[8];
    int count = -1;

    memset(buf, 0x00, sizeof(buf));
    AKSL_CHECK_STATUS_MSG_CONTAINS(
	aksl_snprintf(&count, buf, sizeof(buf), "%s", "far too long for eight bytes"),
	AKERR_OUTOFBOUNDS, "truncated");
    AKSL_CHECK(count == 0);
    return 0;
}

/* Exactly filling the buffer is not truncation; one byte more is. */
static int test_snprintf_boundary_is_exact(void)
{
    char buf[8];
    int count = -1;

    /* 7 characters plus the NUL is exactly sizeof(buf). */
    AKSL_CHECK_OK(aksl_snprintf(&count, buf, sizeof(buf), "%s", "1234567"));
    AKSL_CHECK(count == 7);
    AKSL_CHECK(strcmp(buf, "1234567") == 0);

    count = -1;
    AKSL_CHECK_STATUS(aksl_snprintf(&count, buf, sizeof(buf), "%s", "12345678"),
		      AKERR_OUTOFBOUNDS);
    AKSL_CHECK(count == 0);
    return 0;
}

static int test_snprintf_rejects_null_arguments_and_zero_size(void)
{
    char buf[8];
    int count = 0;

    memset(buf, 0x00, sizeof(buf));
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(NULL, buf, sizeof(buf), "x"),
				   AKERR_NULLPOINTER, "count=");
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, NULL, 8, "x"),
				   AKERR_NULLPOINTER, "str=");
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, buf, sizeof(buf), NULL),
				   AKERR_NULLPOINTER, "format=");
    /* size 0 leaves no room even for the terminator, so there is nothing to do. */
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_snprintf(&count, buf, 0, "x"),
				   AKERR_VALUE, "size=0");
    return 0;
}

static int test_fprintf_writes_to_stream(void)
{
    char path[AKSL_TMP_MAX];
    char readback[64];
    FILE *fp = NULL;
    int count = -1;

    AKSL_CHECK(aksl_temp_file(path, sizeof(path)) == 0);
    AKSL_CHECK_OK(aksl_fopen(path, "w", &fp));
    AKSL_CHECK_OK(aksl_fprintf(&count, fp, "%s %d", "value", 42));
    AKSL_CHECK_OK(aksl_fclose(fp));

    AKSL_CHECK(count == 8);
    AKSL_CHECK(read_file(path, readback, sizeof(readback)) == 8);
    AKSL_CHECK(strcmp(readback, "value 42") == 0);
    AKSL_CHECK(unlink(path) == 0);
    return 0;
}

/*
 * vfprintf on a stream opened "r" fails outright, so the wrapper reports the
 * errno it saw (EBADF on glibc). *count is 0 afterwards, not vfprintf's -1:
 * TODO.md 1.3 recorded the negative count as a contract gap, and this is the
 * assertion that closes it.
 */
static int test_fprintf_to_read_only_stream_reports_errno(void)
{
    char path[AKSL_TMP_MAX];
    FILE *fp = NULL;
    int count = 99;

    AKSL_CHECK(aksl_temp_file(path, sizeof(path)) == 0);
    AKSL_CHECK_OK(aksl_fopen(path, "r", &fp));
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_fprintf(&count, fp, "%d", 1),
				   EBADF, "Short write");
    AKSL_CHECK(count == 0);
    AKSL_CHECK_OK(aksl_fclose(fp));
    AKSL_CHECK(unlink(path) == 0);
    return 0;
}

static int test_fprintf_rejects_null_arguments(void)
{
    int count = 0;

    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_fprintf(NULL, stdout, "x"),
				   AKERR_NULLPOINTER, "count=");
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_fprintf(&count, NULL, "x"),
				   AKERR_NULLPOINTER, "stream=");
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_fprintf(&count, stdout, NULL),
				   AKERR_NULLPOINTER, "format=");
    return 0;
}

/*
 * aksl_printf writes to stdout, so stdout is pointed at a temp file for the
 * duration of the call and then restored through a dup of the original
 * descriptor. Nothing between the freopen and the dup2 may return early: an
 * assertion there would leave stdout attached to the temp file for the rest of
 * the run, and the test report itself would vanish.
 */
static int test_printf_writes_to_stdout(void)
{
    char path[AKSL_TMP_MAX];
    char readback[64];
    akerr_ErrorContext *err = NULL;
    int count = -1;
    int saved = -1;
    int restored = -1;

    AKSL_CHECK(aksl_temp_file(path, sizeof(path)) == 0);

    fflush(stdout);
    saved = dup(fileno(stdout));
    AKSL_CHECK(saved >= 0);
    if ( freopen(path, "w", stdout) == NULL ) {
	close(saved);
	AKSL_CHECK(0);
    }

    err = aksl_printf(&count, "%s#%d", "out", 5);

    fflush(stdout);
    restored = dup2(saved, fileno(stdout));
    close(saved);
    clearerr(stdout);

    AKSL_CHECK(restored >= 0);
    AKSL_CHECK(aksl_take(err) == 0);
    AKSL_CHECK(count == 5);
    AKSL_CHECK(read_file(path, readback, sizeof(readback)) == 5);
    AKSL_CHECK(strcmp(readback, "out#5") == 0);
    AKSL_CHECK(unlink(path) == 0);
    return 0;
}

static int test_printf_rejects_null_arguments(void)
{
    int count = 0;

    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_printf(NULL, "x"),
				   AKERR_NULLPOINTER, "count=");
    AKSL_CHECK_STATUS_MSG_CONTAINS(aksl_printf(&count, NULL),
				   AKERR_NULLPOINTER, "format=");
    return 0;
}

/*
 * The va_list forms are what the variadic ones are built on, and TODO.md 3.1
 * wanted them exposed so consumers can write their own variadic wrappers. This
 * is a consumer doing exactly that.
 */
static akerr_ErrorContext AKERR_NOIGNORE *consumer_wrapper(int *count, char *buf, size_t n,
							   const char *fmt, ...)
{
    va_list args;
    akerr_ErrorContext *raised = NULL;

    va_start(args, fmt);
    raised = aksl_vsnprintf(count, buf, n, fmt, args);
    va_end(args);
    return raised;
}

static int test_va_list_forms_are_usable_from_outside(void)
{
    char buf[32];
    int count = -1;

    memset(buf, 0x00, sizeof(buf));
    AKSL_CHECK_OK(consumer_wrapper(&count, buf, sizeof(buf), "%s/%d", "via", 3));
    AKSL_CHECK(count == 5);
    AKSL_CHECK(strcmp(buf, "via/3") == 0);

    /* The error contract survives the extra layer intact. */
    AKSL_CHECK_STATUS(consumer_wrapper(&count, buf, 4, "%s", "too long"),
		      AKERR_OUTOFBOUNDS);
    AKSL_CHECK(count == 0);
    return 0;
}

/*
 * Regression cover for the missing va_end (TODO.md 2.1.4). Nothing here can
 * assert on register-save state directly; the point is to run the variadic
 * wrappers enough times, with enough arguments, that the sanitizer build has
 * something to trip over.
 */
static int test_variadic_wrappers_survive_repeated_calls(void)
{
    char buf[128];
    int count = 0;
    int i = 0;

    for ( i = 0; i < 512; i++ ) {
	AKSL_CHECK_OK(aksl_snprintf(&count, buf, sizeof(buf), "%d %s %ld %c %f",
				    i, "iteration", (long)i, 'x', (double)i));
	AKSL_CHECK(count > 0);
	AKSL_CHECK((size_t)count == strlen(buf));
    }
    return 0;
}

int main(void)
{
    int failures = 0;

    akerr_init();

    AKSL_RUN(failures, test_snprintf_writes_text_and_count);
    AKSL_RUN(failures, test_snprintf_empty_format_writes_nothing);
    AKSL_RUN(failures, test_snprintf_truncation_is_an_error);
    AKSL_RUN(failures, test_snprintf_boundary_is_exact);
    AKSL_RUN(failures, test_snprintf_rejects_null_arguments_and_zero_size);

    AKSL_RUN(failures, test_fprintf_writes_to_stream);
    AKSL_RUN(failures, test_fprintf_to_read_only_stream_reports_errno);
    AKSL_RUN(failures, test_fprintf_rejects_null_arguments);

    AKSL_RUN(failures, test_printf_writes_to_stdout);
    AKSL_RUN(failures, test_printf_rejects_null_arguments);

    AKSL_RUN(failures, test_va_list_forms_are_usable_from_outside);
    AKSL_RUN(failures, test_variadic_wrappers_survive_repeated_calls);

    AKSL_REPORT(failures);
}