#define _GNU_SOURCE
#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <errno.h>
#include <linux/types.h>
#include <sys/wait.h>
#include <sys/syscall.h>
#include <sys/user.h>
#include <sys/mman.h>

#include "linux/ptrace.h"

static int sys_rt_sigqueueinfo(pid_t tgid, int sig, siginfo_t *uinfo)
{
        return syscall(SYS_rt_sigqueueinfo, tgid, sig, uinfo);
}

static int sys_rt_tgsigqueueinfo(pid_t tgid, pid_t tid,
                                        int sig, siginfo_t *uinfo)
{
        return syscall(SYS_rt_tgsigqueueinfo, tgid, tid, sig, uinfo);
}

static int sys_ptrace(int request, pid_t pid, void *addr, void *data)
{
        return syscall(SYS_ptrace, request, pid, addr, data);
}

#define SIGNR 10
#define TEST_SICODE_PRIV        -1
#define TEST_SICODE_SHARE       -2

#ifndef PAGE_SIZE
#define PAGE_SIZE sysconf(_SC_PAGESIZE)
#endif

#define err(fmt, ...)                                           \
                fprintf(stderr,                                 \
                        "Error (%s:%d): " fmt,                  \
                        __FILE__, __LINE__, ##__VA_ARGS__)

static int check_error_paths(pid_t child)
{
        struct ptrace_peeksiginfo_args arg;
        int ret, exit_code = -1;
        void *addr_rw, *addr_ro;

        /*
         * Allocate two contiguous pages. The first one is for read-write,
         * another is for read-only.
         */
        addr_rw = mmap(NULL, 2 * PAGE_SIZE, PROT_READ | PROT_WRITE,
                                MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
        if (addr_rw == MAP_FAILED) {
                err("mmap() failed: %m\n");
                return 1;
        }

        addr_ro = mmap(addr_rw + PAGE_SIZE, PAGE_SIZE, PROT_READ,
                        MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
        if (addr_ro == MAP_FAILED) {
                err("mmap() failed: %m\n");
                goto out;
        }

        arg.nr = SIGNR;
        arg.off = 0;

        /* Unsupported flags */
        arg.flags = ~0;
        ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg, addr_rw);
        if (ret != -1 || errno != EINVAL) {
                err("sys_ptrace() returns %d (expected -1),"
                                " errno %d (expected %d): %m\n",
                                ret, errno, EINVAL);
                goto out;
        }
        arg.flags = 0;

        /* A part of the buffer is read-only */
        ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg,
                                        addr_ro - sizeof(siginfo_t) * 2);
        if (ret != 2) {
                err("sys_ptrace() returns %d (expected 2): %m\n", ret);
                goto out;
        }

        /* Read-only buffer */
        ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg, addr_ro);
        if (ret != -1 && errno != EFAULT) {
                err("sys_ptrace() returns %d (expected -1),"
                                " errno %d (expected %d): %m\n",
                                ret, errno, EFAULT);
                goto out;
        }

        exit_code = 0;
out:
        munmap(addr_rw, 2 * PAGE_SIZE);
        return exit_code;
}

int check_direct_path(pid_t child, int shared, int nr)
{
        struct ptrace_peeksiginfo_args arg = {.flags = 0, .nr = nr, .off = 0};
        int i, j, ret, exit_code = -1;
        siginfo_t siginfo[SIGNR];
        int si_code;

        if (shared == 1) {
                arg.flags = PTRACE_PEEKSIGINFO_SHARED;
                si_code = TEST_SICODE_SHARE;
        } else {
                arg.flags = 0;
                si_code = TEST_SICODE_PRIV;
        }

        for (i = 0; i < SIGNR; ) {
                arg.off = i;
                ret = sys_ptrace(PTRACE_PEEKSIGINFO, child, &arg, siginfo);
                if (ret == -1) {
                        err("ptrace() failed: %m\n");
                        goto out;
                }

                if (ret == 0)
                        break;

                for (j = 0; j < ret; j++, i++) {
                        if (siginfo[j].si_code == si_code &&
                            siginfo[j].si_int == i)
                                continue;

                        err("%d: Wrong siginfo i=%d si_code=%d si_int=%d\n",
                             shared, i, siginfo[j].si_code, siginfo[j].si_int);
                        goto out;
                }
        }

        if (i != SIGNR) {
                err("Only %d signals were read\n", i);
                goto out;
        }

        exit_code = 0;
out:
        return exit_code;
}

int main(int argc, char *argv[])
{
        siginfo_t siginfo[SIGNR];
        int i, exit_code = 1;
        sigset_t blockmask;
        pid_t child;

        sigemptyset(&blockmask);
        sigaddset(&blockmask, SIGRTMIN);
        sigprocmask(SIG_BLOCK, &blockmask, NULL);

        child = fork();
        if (child == -1) {
                err("fork() failed: %m");
                return 1;
        } else if (child == 0) {
                pid_t ppid = getppid();
                while (1) {
                        if (ppid != getppid())
                                break;
                        sleep(1);
                }
                return 1;
        }

        /* Send signals in process-wide and per-thread queues */
        for (i = 0; i < SIGNR; i++) {
                siginfo->si_code = TEST_SICODE_SHARE;
                siginfo->si_int = i;
                sys_rt_sigqueueinfo(child, SIGRTMIN, siginfo);

                siginfo->si_code = TEST_SICODE_PRIV;
                siginfo->si_int = i;
                sys_rt_tgsigqueueinfo(child, child, SIGRTMIN, siginfo);
        }

        if (sys_ptrace(PTRACE_ATTACH, child, NULL, NULL) == -1)
                return 1;

        waitpid(child, NULL, 0);

        /* Dump signals one by one*/
        if (check_direct_path(child, 0, 1))
                goto out;
        /* Dump all signals for one call */
        if (check_direct_path(child, 0, SIGNR))
                goto out;

        /*
         * Dump signal from the process-wide queue.
         * The number of signals is not multible to the buffer size
         */
        if (check_direct_path(child, 1, 3))
                goto out;

        if (check_error_paths(child))
                goto out;

        printf("PASS\n");
        exit_code = 0;
out:
        if (sys_ptrace(PTRACE_KILL, child, NULL, NULL) == -1)
                return 1;

        waitpid(child, NULL, 0);

        return exit_code;
}