// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <linux/kconfig.h>
#include <linux/kernel.h>
#include <linux/rbtree.h>
#include <linux/types.h>
#include <inttypes.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/param.h>
#include <sys/utsname.h>
#include <perf/cpumap.h>
#include <perf/evlist.h>
#include <perf/mmap.h>

#include "debug.h"
#include "dso.h"
#include "env.h"
#include "parse-events.h"
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"
#include "machine.h"
#include "map.h"
#include "symbol.h"
#include "event.h"
#include "record.h"
#include "util/mmap.h"
#include "util/string2.h"
#include "util/synthetic-events.h"
#include "util/util.h"
#include "thread.h"

#include "tests.h"

#include <linux/ctype.h>

#define BUFSZ   1024
#define READLEN 128

struct tested_section {
        struct rb_node rb_node;
        u64 addr;
        char *path;
};

static bool tested_code_insert_or_exists(const char *path, u64 addr,
                                         struct rb_root *tested_sections)
{
        struct rb_node **node = &tested_sections->rb_node;
        struct rb_node *parent = NULL;
        struct tested_section *data;

        while (*node) {
                int cmp;

                parent = *node;
                data = rb_entry(*node, struct tested_section, rb_node);
                cmp = strcmp(path, data->path);
                if (!cmp) {
                        if (addr < data->addr)
                                cmp = -1;
                        else if (addr > data->addr)
                                cmp = 1;
                        else
                                return true; /* already tested */
                }

                if (cmp < 0)
                        node = &(*node)->rb_left;
                else
                        node = &(*node)->rb_right;
        }

        data = zalloc(sizeof(*data));
        if (!data)
                return true;

        data->addr = addr;
        data->path = strdup(path);
        if (!data->path) {
                free(data);
                return true;
        }
        rb_link_node(&data->rb_node, parent, node);
        rb_insert_color(&data->rb_node, tested_sections);
        return false;
}

static void tested_sections__free(struct rb_root *root)
{
        while (!RB_EMPTY_ROOT(root)) {
                struct rb_node *node = rb_first(root);
                struct tested_section *ts = rb_entry(node,
                                                     struct tested_section,
                                                     rb_node);

                rb_erase(node, root);
                free(ts->path);
                free(ts);
        }
}

static size_t read_objdump_chunk(const char **line, unsigned char **buf,
                                 size_t *buf_len)
{
        size_t bytes_read = 0;
        unsigned char *chunk_start = *buf;

        /* Read bytes */
        while (*buf_len > 0) {
                char c1, c2;

                /* Get 2 hex digits */
                c1 = *(*line)++;
                if (!isxdigit(c1))
                        break;
                c2 = *(*line)++;
                if (!isxdigit(c2))
                        break;

                /* Store byte and advance buf */
                **buf = (hex(c1) << 4) | hex(c2);
                (*buf)++;
                (*buf_len)--;
                bytes_read++;

                /* End of chunk? */
                if (isspace(**line))
                        break;
        }

        /*
         * objdump will display raw insn as LE if code endian
         * is LE and bytes_per_chunk > 1. In that case reverse
         * the chunk we just read.
         *
         * see disassemble_bytes() at binutils/objdump.c for details
         * how objdump chooses display endian)
         */
        if (bytes_read > 1 && !host_is_bigendian()) {
                unsigned char *chunk_end = chunk_start + bytes_read - 1;
                unsigned char tmp;

                while (chunk_start < chunk_end) {
                        tmp = *chunk_start;
                        *chunk_start = *chunk_end;
                        *chunk_end = tmp;
                        chunk_start++;
                        chunk_end--;
                }
        }

        return bytes_read;
}

static size_t read_objdump_line(const char *line, unsigned char *buf,
                                size_t buf_len)
{
        const char *p;
        size_t ret, bytes_read = 0;

        /* Skip to a colon */
        p = strchr(line, ':');
        if (!p)
                return 0;
        p++;

        /* Skip initial spaces */
        while (*p) {
                if (!isspace(*p))
                        break;
                p++;
        }

        do {
                ret = read_objdump_chunk(&p, &buf, &buf_len);
                bytes_read += ret;
                p++;
        } while (ret > 0);

        /* return number of successfully read bytes */
        return bytes_read;
}

static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
{
        char *line = NULL;
        size_t line_len, off_last = 0;
        ssize_t ret;
        int err = 0;
        u64 addr, last_addr = start_addr;

        while (off_last < *len) {
                size_t off, read_bytes, written_bytes;
                unsigned char tmp[BUFSZ];

                ret = getline(&line, &line_len, f);
                if (feof(f))
                        break;
                if (ret < 0) {
                        pr_debug("getline failed\n");
                        err = -1;
                        break;
                }

                /* read objdump data into temporary buffer */
                read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
                if (!read_bytes)
                        continue;

                if (sscanf(line, "%"PRIx64, &addr) != 1)
                        continue;
                if (addr < last_addr) {
                        pr_debug("addr going backwards, read beyond section?\n");
                        break;
                }
                last_addr = addr;

                /* copy it from temporary buffer to 'buf' according
                 * to address on current objdump line */
                off = addr - start_addr;
                if (off >= *len)
                        break;
                written_bytes = MIN(read_bytes, *len - off);
                memcpy(buf + off, tmp, written_bytes);
                off_last = off + written_bytes;
        }

        /* len returns number of bytes that could not be read */
        *len -= off_last;

        free(line);

        return err;
}

/*
 * Only gets GNU objdump version. Returns 0 for llvm-objdump.
 */
static int objdump_version(void)
{
        size_t line_len;
        char cmd[PATH_MAX * 2];
        char *line = NULL;
        const char *fmt;
        FILE *f;
        int ret;

        int version_tmp, version_num = 0;
        char *version = 0, *token;

        fmt = "%s --version";
        ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path);
        if (ret <= 0 || (size_t)ret >= sizeof(cmd))
                return -1;
        /* Ignore objdump errors */
        strcat(cmd, " 2>/dev/null");
        f = popen(cmd, "r");
        if (!f) {
                pr_debug("popen failed\n");
                return -1;
        }
        /* Get first line of objdump --version output */
        ret = getline(&line, &line_len, f);
        pclose(f);
        if (ret < 0) {
                pr_debug("getline failed\n");
                return -1;
        }

        token = strsep(&line, " ");
        if (token != NULL && !strcmp(token, "GNU")) {
                // version is last part of first line of objdump --version output.
                while ((token = strsep(&line, " ")))
                        version = token;

                // Convert version into a format we can compare with
                token = strsep(&version, ".");
                version_num = atoi(token);
                if (version_num)
                        version_num *= 10000;

                token = strsep(&version, ".");
                version_tmp = atoi(token);
                if (token)
                        version_num += version_tmp * 100;

                token = strsep(&version, ".");
                version_tmp = atoi(token);
                if (token)
                        version_num += version_tmp;
        }

        return version_num;
}

static int read_via_objdump(const char *filename, u64 addr, void *buf,
                            size_t len)
{
        u64 stop_address = addr + len;
        struct utsname uname_buf;
        char cmd[PATH_MAX * 2];
        const char *fmt;
        FILE *f;
        int ret;

        ret = uname(&uname_buf);
        if (ret) {
                pr_debug("uname failed\n");
                return -1;
        }

        if (!strncmp(uname_buf.machine, "riscv", 5)) {
                int version = objdump_version();

                /* Default to this workaround if version parsing fails */
                if (version < 0 || version > 24100) {
                        /*
                         * Starting at riscv objdump version 2.41, dumping in
                         * the middle of an instruction is not supported. riscv
                         * instructions are aligned along 2-byte intervals and
                         * can be either 2-bytes or 4-bytes. This makes it
                         * possible that the stop-address lands in the middle of
                         * a 4-byte instruction. Increase the stop_address by
                         * two to ensure an instruction is not cut in half, but
                         * leave the len as-is so only the expected number of
                         * bytes are collected.
                         */
                        stop_address += 2;
                }
        }

        fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
        ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, stop_address,
                       filename);
        if (ret <= 0 || (size_t)ret >= sizeof(cmd))
                return -1;

        pr_debug("Objdump command is: %s\n", cmd);

        /* Ignore objdump errors */
        strcat(cmd, " 2>/dev/null");

        f = popen(cmd, "r");
        if (!f) {
                pr_debug("popen failed\n");
                return -1;
        }

        ret = read_objdump_output(f, buf, &len, addr);
        if (len) {
                pr_debug("objdump read too few bytes: %zd\n", len);
                if (!ret)
                        ret = len;
        }

        pclose(f);

        return ret;
}

static void dump_buf(unsigned char *buf, size_t len)
{
        size_t i;

        for (i = 0; i < len; i++) {
                pr_debug("0x%02x ", buf[i]);
                if (i % 16 == 15)
                        pr_debug("\n");
        }
        pr_debug("\n");
}

static int read_object_code(u64 addr, size_t len, u8 cpumode,
                            struct thread *thread,
                            struct rb_root *tested_sections)
{
        struct addr_location al;
        unsigned char buf1[BUFSZ] = {0};
        unsigned char buf2[BUFSZ] = {0};
        size_t ret_len;
        u64 objdump_addr;
        u64 skip_addr;
        const char *objdump_name;
        char decomp_name[KMOD_DECOMP_LEN];
        bool decomp = false;
        int ret, err = 0;
        struct dso *dso;

        pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);

        addr_location__init(&al);
        if (!thread__find_map(thread, cpumode, addr, &al) || !map__dso(al.map)) {
                if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
                        pr_debug("Hypervisor address can not be resolved - skipping\n");
                        goto out;
                }

                pr_debug("thread__find_map failed\n");
                err = -1;
                goto out;
        }
        dso = map__dso(al.map);
        pr_debug("File is: %s\n", dso__long_name(dso));

        if (dso__symtab_type(dso) == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(dso)) {
                pr_debug("Unexpected kernel address - skipping\n");
                goto out;
        }

        /*
         * Don't retest the same addresses. objdump struggles with kcore - try
         * each map only once even if the address is different.
         */
        skip_addr = dso__is_kcore(dso) ? map__start(al.map) : al.addr;
        if (tested_code_insert_or_exists(dso__long_name(dso), skip_addr,
                                         tested_sections)) {
                pr_debug("Already tested %s @ %#"PRIx64" - skipping\n",
                         dso__long_name(dso), skip_addr);
                goto out;
        }

        pr_debug("On file address is: %#"PRIx64"\n", al.addr);

        if (len > BUFSZ)
                len = BUFSZ;

        /* Do not go off the map */
        if (addr + len > map__end(al.map))
                len = map__end(al.map) - addr;

        /*
         * Some architectures (ex: powerpc) have stubs (trampolines) in kernel
         * modules to manage long jumps. Check if the ip offset falls in stubs
         * sections for kernel modules. And skip module address after text end
         */
        if (dso__is_kmod(dso) && al.addr > dso__text_end(dso)) {
                pr_debug("skipping the module address %#"PRIx64" after text end\n", al.addr);
                goto out;
        }

        /* Read the object code using perf */
        ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)),
                                        al.addr, buf1, len);
        if (ret_len != len) {
                pr_debug("dso__data_read_offset failed\n");
                err = -1;
                goto out;
        }

        /*
         * Converting addresses for use by objdump requires more information.
         * map__load() does that.  See map__rip_2objdump() for details.
         */
        if (map__load(al.map)) {
                err = -1;
                goto out;
        }

        objdump_name = dso__long_name(dso);
        if (dso__needs_decompress(dso)) {
                if (dso__decompress_kmodule_path(dso, objdump_name,
                                                 decomp_name,
                                                 sizeof(decomp_name)) < 0) {
                        pr_debug("decompression failed\n");
                        err = -1;
                        goto out;
                }

                decomp = true;
                objdump_name = decomp_name;
        }

        /* Read the object code using objdump */
        objdump_addr = map__rip_2objdump(al.map, al.addr);
        ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);

        if (decomp)
                unlink(objdump_name);

        if (ret > 0) {
                /*
                 * The kernel maps are inaccurate - assume objdump is right in
                 * that case.
                 */
                if (cpumode == PERF_RECORD_MISC_KERNEL ||
                    cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
                        len -= ret;
                        if (len) {
                                pr_debug("Reducing len to %zu\n", len);
                        } else if (dso__is_kcore(dso)) {
                                /*
                                 * objdump cannot handle very large segments
                                 * that may be found in kcore.
                                 */
                                pr_debug("objdump failed for kcore");
                                pr_debug(" - skipping\n");
                        } else {
                                err = -1;
                        }
                        goto out;
                }
        }
        if (ret < 0) {
                pr_debug("read_via_objdump failed\n");
                err = -1;
                goto out;
        }

        /* The results should be identical */
        if (memcmp(buf1, buf2, len)) {
                pr_debug("Bytes read differ from those read by objdump\n");
                pr_debug("buf1 (dso):\n");
                dump_buf(buf1, len);
                pr_debug("buf2 (objdump):\n");
                dump_buf(buf2, len);
                err = -1;
                goto out;
        }
        pr_debug("Bytes read match those read by objdump\n");
out:
        addr_location__exit(&al);
        return err;
}

static int process_sample_event(struct machine *machine, struct evlist *evlist,
                                union perf_event *event,
                                struct rb_root *tested_sections)
{
        struct perf_sample sample;
        struct thread *thread;
        int ret;

        perf_sample__init(&sample, /*all=*/false);
        ret = evlist__parse_sample(evlist, event, &sample);
        if (ret) {
                pr_debug("evlist__parse_sample failed\n");
                ret = -1;
                goto out;
        }

        thread = machine__findnew_thread(machine, sample.pid, sample.tid);
        if (!thread) {
                pr_debug("machine__findnew_thread failed\n");
                ret = -1;
                goto out;
        }

        ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread,
                               tested_sections);
        thread__put(thread);
out:
        perf_sample__exit(&sample);
        return ret;
}

static int process_event(struct machine *machine, struct evlist *evlist,
                         union perf_event *event, struct rb_root *tested_sections)
{
        if (event->header.type == PERF_RECORD_SAMPLE)
                return process_sample_event(machine, evlist, event,
                                            tested_sections);

        if (event->header.type == PERF_RECORD_THROTTLE ||
            event->header.type == PERF_RECORD_UNTHROTTLE)
                return 0;

        if (event->header.type < PERF_RECORD_MAX) {
                int ret;

                ret = machine__process_event(machine, event, NULL);
                if (ret < 0)
                        pr_debug("machine__process_event failed, event type %u\n",
                                 event->header.type);
                return ret;
        }

        return 0;
}

static int process_events(struct machine *machine, struct evlist *evlist,
                          struct rb_root *tested_sections)
{
        union perf_event *event;
        struct mmap *md;
        int i, ret;

        for (i = 0; i < evlist->core.nr_mmaps; i++) {
                md = &evlist->mmap[i];
                if (perf_mmap__read_init(&md->core) < 0)
                        continue;

                while ((event = perf_mmap__read_event(&md->core)) != NULL) {
                        ret = process_event(machine, evlist, event, tested_sections);
                        perf_mmap__consume(&md->core);
                        if (ret < 0)
                                return ret;
                }
                perf_mmap__read_done(&md->core);
        }
        return 0;
}

static int comp(const void *a, const void *b)
{
        return *(int *)a - *(int *)b;
}

static void do_sort_something(void)
{
        int buf[40960], i;

        for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
                buf[i] = ARRAY_SIZE(buf) - i - 1;

        qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);

        for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
                if (buf[i] != i) {
                        pr_debug("qsort failed\n");
                        break;
                }
        }
}

static void sort_something(void)
{
        int i;

        for (i = 0; i < 10; i++)
                do_sort_something();
}

static void syscall_something(void)
{
        int pipefd[2];
        int i;

        for (i = 0; i < 1000; i++) {
                if (pipe(pipefd) < 0) {
                        pr_debug("pipe failed\n");
                        break;
                }
                close(pipefd[1]);
                close(pipefd[0]);
        }
}

static void fs_something(void)
{
        const char *test_file_name = "temp-perf-code-reading-test-file--";
        FILE *f;
        int i;

        for (i = 0; i < 1000; i++) {
                f = fopen(test_file_name, "w+");
                if (f) {
                        fclose(f);
                        unlink(test_file_name);
                }
        }
}

static void do_something(void)
{
        fs_something();

        sort_something();

        syscall_something();
}

enum {
        TEST_CODE_READING_OK,
        TEST_CODE_READING_NO_VMLINUX,
        TEST_CODE_READING_NO_KCORE,
        TEST_CODE_READING_NO_ACCESS,
        TEST_CODE_READING_NO_KERNEL_OBJ,
};

static int do_test_code_reading(bool try_kcore)
{
        struct machine *machine;
        struct thread *thread;
        struct record_opts opts = {
                .mmap_pages          = UINT_MAX,
                .user_freq           = UINT_MAX,
                .user_interval       = ULLONG_MAX,
                .freq                = 500,
                .target              = {
                        .uses_mmap   = true,
                },
        };
        struct rb_root tested_sections = RB_ROOT;
        struct perf_thread_map *threads = NULL;
        struct perf_cpu_map *cpus = NULL;
        struct evlist *evlist = NULL;
        struct evsel *evsel = NULL;
        int err = -1, ret;
        pid_t pid;
        struct map *map;
        bool have_vmlinux, have_kcore;
        struct dso *dso;
        const char *events[] = { "cpu-cycles", "cpu-cycles:u", "cpu-clock", "cpu-clock:u", NULL };
        int evidx = 0;
        struct perf_env host_env;

        pid = getpid();

        perf_env__init(&host_env);
        machine = machine__new_host(&host_env);

        ret = machine__create_kernel_maps(machine);
        if (ret < 0) {
                pr_debug("machine__create_kernel_maps failed\n");
                goto out_err;
        }

        /* Force the use of kallsyms instead of vmlinux to try kcore */
        if (try_kcore)
                symbol_conf.kallsyms_name = "/proc/kallsyms";

        /* Load kernel map */
        map = machine__kernel_map(machine);
        ret = map__load(map);
        if (ret < 0) {
                pr_debug("map__load failed\n");
                goto out_err;
        }
        dso = map__dso(map);
        have_vmlinux = dso__is_vmlinux(dso);
        have_kcore = dso__is_kcore(dso);

        /* 2nd time through we just try kcore */
        if (try_kcore && !have_kcore)
                return TEST_CODE_READING_NO_KCORE;

        /* No point getting kernel events if there is no kernel object */
        if (!have_vmlinux && !have_kcore)
                evidx++;

        threads = thread_map__new_by_tid(pid);
        if (!threads) {
                pr_debug("thread_map__new_by_tid failed\n");
                goto out_err;
        }

        ret = perf_event__synthesize_thread_map(NULL, threads,
                                                perf_event__process, machine,
                                                true, false);
        if (ret < 0) {
                pr_debug("perf_event__synthesize_thread_map failed\n");
                goto out_err;
        }

        thread = machine__findnew_thread(machine, pid, pid);
        if (!thread) {
                pr_debug("machine__findnew_thread failed\n");
                goto out_put;
        }

        cpus = perf_cpu_map__new_online_cpus();
        if (!cpus) {
                pr_debug("perf_cpu_map__new failed\n");
                goto out_put;
        }

        while (events[evidx]) {
                const char *str;

                evlist = evlist__new();
                if (!evlist) {
                        pr_debug("evlist__new failed\n");
                        goto out_put;
                }

                perf_evlist__set_maps(&evlist->core, cpus, threads);

                str = events[evidx];
                pr_debug("Parsing event '%s'\n", str);
                ret = parse_event(evlist, str);
                if (ret < 0) {
                        pr_debug("parse_events failed\n");
                        goto out_put;
                }

                evlist__config(evlist, &opts, NULL);

                evlist__for_each_entry(evlist, evsel) {
                        evsel->core.attr.comm = 1;
                        evsel->core.attr.disabled = 1;
                        evsel->core.attr.enable_on_exec = 0;
                }

                ret = evlist__open(evlist);
                if (ret < 0) {
                        evidx++;

                        if (events[evidx] == NULL && verbose > 0) {
                                char errbuf[512];
                                evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
                                pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
                        }

                        perf_evlist__set_maps(&evlist->core, NULL, NULL);
                        evlist__delete(evlist);
                        evlist = NULL;
                        continue;
                }
                break;
        }

        if (events[evidx] == NULL)
                goto out_put;

        ret = evlist__mmap(evlist, UINT_MAX);
        if (ret < 0) {
                pr_debug("evlist__mmap failed\n");
                goto out_put;
        }

        evlist__enable(evlist);

        do_something();

        evlist__disable(evlist);

        ret = process_events(machine, evlist, &tested_sections);
        if (ret < 0)
                goto out_put;

        if (!have_vmlinux && !have_kcore && !try_kcore)
                err = TEST_CODE_READING_NO_KERNEL_OBJ;
        else if (!have_vmlinux && !try_kcore)
                err = TEST_CODE_READING_NO_VMLINUX;
        else if (strstr(events[evidx], ":u"))
                err = TEST_CODE_READING_NO_ACCESS;
        else
                err = TEST_CODE_READING_OK;
out_put:
        thread__put(thread);
out_err:
        evlist__delete(evlist);
        perf_cpu_map__put(cpus);
        perf_thread_map__put(threads);
        machine__delete(machine);
        perf_env__exit(&host_env);
        tested_sections__free(&tested_sections);

        return err;
}

static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
{
        int ret;

        ret = do_test_code_reading(false);
        if (!ret)
                ret = do_test_code_reading(true);

        switch (ret) {
        case TEST_CODE_READING_OK:
                return 0;
        case TEST_CODE_READING_NO_VMLINUX:
                pr_debug("no vmlinux\n");
                return 0;
        case TEST_CODE_READING_NO_KCORE:
                pr_debug("no kcore\n");
                return 0;
        case TEST_CODE_READING_NO_ACCESS:
                pr_debug("no access\n");
                return 0;
        case TEST_CODE_READING_NO_KERNEL_OBJ:
                pr_debug("no kernel obj\n");
                return 0;
        default:
                return -1;
        };
}

DEFINE_SUITE("Object code reading", code_reading);