-/*
- * Copyright (C) 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
- *
- * SPDX-License-Identifier: LGPL-2.1-only
- *
- */
-
-#include <fcntl.h>
-#include <stdio.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-#include <common/error.h>
-#include <common/align.h>
-
-#include "utils.h"
-
-#define MAX_LEN 16
-
-/*
- * The LTTng system call tracing facilities can't handle page faults at the
- * moment. If a fault would occur while reading a syscall argument, the
- * tracer will report an empty string (""). Since the proper execution of the
- * tests which use this generator depends on some syscall string arguments being
- * present, this util allows us to mitigate the page-fault risk.
- *
- * This isn't a proper fix; it is simply the best we can do for now.
- * See bug #1261 for more context.
- */
-static
-void prefault_string(const char *p)
-{
- const char * const end = p + strlen(p) + 1;
-
- while (p < end) {
- /*
- * Trigger a read attempt on *p, faulting-in the pages
- * for reading.
- */
- asm volatile("" : : "m"(*p));
- p += sysconf(_SC_PAGE_SIZE);
- }
-}
-
-static
-int open_read_close(const char *path)
-{
- int fd, ret;
- char buf[MAX_LEN];
-
- /*
- * Start generating syscalls. We use syscall(2) to prevent libc from
- * changing the underlying syscall (e.g. calling openat(2) instead of
- * open(2)).
- */
- prefault_string(path);
- fd = syscall(SYS_openat, AT_FDCWD, path, O_RDONLY);
- if (fd < 0) {
- PERROR_NO_LOGGER("Failed to open file with openat(): path = '%s'", path);
- ret = -1;
- goto error;
- }
-
- ret = syscall(SYS_read, fd, buf, MAX_LEN);
- if (ret < 0) {
- PERROR_NO_LOGGER("Failed to read file: path = '%s', fd = %d, length = %d",
- path, fd, MAX_LEN);
- ret = -1;
- goto error;
- }
-
- ret = syscall(SYS_close, fd);
- if (ret == -1) {
- PERROR_NO_LOGGER("Failed to close file: path = '%s', fd = %d", path, fd);
- ret = -1;
- goto error;
- }
-
-error:
- return ret;
-}
-
-/*
- * The process waits for the creation of a file passed as argument from an
- * external processes to execute a syscall and exiting. This is useful for tests
- * in combinaison with LTTng's PID tracker feature where we can trace the kernel
- * events generated by our test process only.
- */
-int main(int argc, char **argv)
-{
- int ret;
- const char *start_file, *path1, *path2;
-
- if (argc != 4) {
- fprintf(stderr, "Error: Missing argument\n");
- fprintf(stderr, "USAGE: %s PATH_WAIT_FILE PATH1_TO_OPEN PATH2_TO_OPEN\n", argv[0]);
- ret = -1;
- goto error;
- }
-
- start_file = argv[1];
- path1 = argv[2];
- path2 = argv[3];
-
- /*
- * Wait for the start_file to be created by an external process
- * (typically the test script) before executing the syscalls.
- */
- ret = wait_on_file(start_file);
- if (ret != 0) {
- goto error;
- }
-
- /*
- * Start generating syscalls. We use syscall(2) to prevent libc to change
- * the underlying syscall. e.g. calling openat(2) instead of open(2).
- */
- ret = open_read_close(path1);
- if (ret == -1) {
- ret = -1;
- goto error;
- }
-
- ret = open_read_close(path2);
- if (ret == -1) {
- ret = -1;
- goto error;
- }
-
-error:
- return ret;
-}