#include <linux/compiler.h>
#include <linux/rbtree.h>
#include <string.h>
#include "map.h"
#include "symbol.h"
#include "util.h"
#include "tests.h"
#include "debug.h"
#include "machine.h"

static int vmlinux_matches_kallsyms_filter(struct map *map __maybe_unused,
                                           struct symbol *sym)
{
        bool *visited = symbol__priv(sym);
        *visited = true;
        return 0;
}

#define UM(x) kallsyms_map->unmap_ip(kallsyms_map, (x))

int test__vmlinux_matches_kallsyms(void)
{
        int err = -1;
        struct rb_node *nd;
        struct symbol *sym;
        struct map *kallsyms_map, *vmlinux_map, *map;
        struct machine kallsyms, vmlinux;
        enum map_type type = MAP__FUNCTION;
        struct maps *maps = &vmlinux.kmaps.maps[type];
        u64 mem_start, mem_end;

        /*
         * Step 1:
         *
         * Init the machines that will hold kernel, modules obtained from
         * both vmlinux + .ko files and from /proc/kallsyms split by modules.
         */
        machine__init(&kallsyms, "", HOST_KERNEL_ID);
        machine__init(&vmlinux, "", HOST_KERNEL_ID);

        /*
         * Step 2:
         *
         * Create the kernel maps for kallsyms and the DSO where we will then
         * load /proc/kallsyms. Also create the modules maps from /proc/modules
         * and find the .ko files that match them in /lib/modules/`uname -r`/.
         */
        if (machine__create_kernel_maps(&kallsyms) < 0) {
                pr_debug("machine__create_kernel_maps ");
                goto out;
        }

        /*
         * Step 3:
         *
         * Load and split /proc/kallsyms into multiple maps, one per module.
         */
        if (machine__load_kallsyms(&kallsyms, "/proc/kallsyms", type, NULL) <= 0) {
                pr_debug("dso__load_kallsyms ");
                goto out;
        }

        /*
         * Step 4:
         *
         * kallsyms will be internally on demand sorted by name so that we can
         * find the reference relocation * symbol, i.e. the symbol we will use
         * to see if the running kernel was relocated by checking if it has the
         * same value in the vmlinux file we load.
         */
        kallsyms_map = machine__kernel_map(&kallsyms, type);

        /*
         * Step 5:
         *
         * Now repeat step 2, this time for the vmlinux file we'll auto-locate.
         */
        if (machine__create_kernel_maps(&vmlinux) < 0) {
                pr_debug("machine__create_kernel_maps ");
                goto out;
        }

        vmlinux_map = machine__kernel_map(&vmlinux, type);

        /*
         * Step 6:
         *
         * Locate a vmlinux file in the vmlinux path that has a buildid that
         * matches the one of the running kernel.
         *
         * While doing that look if we find the ref reloc symbol, if we find it
         * we'll have its ref_reloc_symbol.unrelocated_addr and then
         * maps__reloc_vmlinux will notice and set proper ->[un]map_ip routines
         * to fixup the symbols.
         */
        if (machine__load_vmlinux_path(&vmlinux, type,
                                       vmlinux_matches_kallsyms_filter) <= 0) {
                pr_debug("Couldn't find a vmlinux that matches the kernel running on this machine, skipping test\n");
                err = TEST_SKIP;
                goto out;
        }

        err = 0;
        /*
         * Step 7:
         *
         * Now look at the symbols in the vmlinux DSO and check if we find all of them
         * in the kallsyms dso. For the ones that are in both, check its names and
         * end addresses too.
         */
        for (nd = rb_first(&vmlinux_map->dso->symbols[type]); nd; nd = rb_next(nd)) {
                struct symbol *pair, *first_pair;
                bool backwards = true;

                sym  = rb_entry(nd, struct symbol, rb_node);

                if (sym->start == sym->end)
                        continue;

                mem_start = vmlinux_map->unmap_ip(vmlinux_map, sym->start);
                mem_end = vmlinux_map->unmap_ip(vmlinux_map, sym->end);

                first_pair = machine__find_kernel_symbol(&kallsyms, type,
                                                         mem_start, NULL, NULL);
                pair = first_pair;

                if (pair && UM(pair->start) == mem_start) {
next_pair:
                        if (strcmp(sym->name, pair->name) == 0) {
                                /*
                                 * kallsyms don't have the symbol end, so we
                                 * set that by using the next symbol start - 1,
                                 * in some cases we get this up to a page
                                 * wrong, trace_kmalloc when I was developing
                                 * this code was one such example, 2106 bytes
                                 * off the real size. More than that and we
                                 * _really_ have a problem.
                                 */
                                s64 skew = mem_end - UM(pair->end);
                                if (llabs(skew) >= page_size)
                                        pr_debug("%#" PRIx64 ": diff end addr for %s v: %#" PRIx64 " k: %#" PRIx64 "\n",
                                                 mem_start, sym->name, mem_end,
                                                 UM(pair->end));

                                /*
                                 * Do not count this as a failure, because we
                                 * could really find a case where it's not
                                 * possible to get proper function end from
                                 * kallsyms.
                                 */
                                continue;

                        } else {
                                struct rb_node *nnd;
detour:
                                nnd = backwards ? rb_prev(&pair->rb_node) :
                                                  rb_next(&pair->rb_node);
                                if (nnd) {
                                        struct symbol *next = rb_entry(nnd, struct symbol, rb_node);

                                        if (UM(next->start) == mem_start) {
                                                pair = next;
                                                goto next_pair;
                                        }
                                }

                                if (backwards) {
                                        backwards = false;
                                        pair = first_pair;
                                        goto detour;
                                }

                                pr_debug("%#" PRIx64 ": diff name v: %s k: %s\n",
                                         mem_start, sym->name, pair->name);
                        }
                } else
                        pr_debug("%#" PRIx64 ": %s not on kallsyms\n",
                                 mem_start, sym->name);

                err = -1;
        }

        if (!verbose)
                goto out;

        pr_info("Maps only in vmlinux:\n");

        for (map = maps__first(maps); map; map = map__next(map)) {
                struct map *
                /*
                 * If it is the kernel, kallsyms is always "[kernel.kallsyms]", while
                 * the kernel will have the path for the vmlinux file being used,
                 * so use the short name, less descriptive but the same ("[kernel]" in
                 * both cases.
                 */
                pair = map_groups__find_by_name(&kallsyms.kmaps, type,
                                                (map->dso->kernel ?
                                                        map->dso->short_name :
                                                        map->dso->name));
                if (pair)
                        pair->priv = 1;
                else
                        map__fprintf(map, stderr);
        }

        pr_info("Maps in vmlinux with a different name in kallsyms:\n");

        for (map = maps__first(maps); map; map = map__next(map)) {
                struct map *pair;

                mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start);
                mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end);

                pair = map_groups__find(&kallsyms.kmaps, type, mem_start);
                if (pair == NULL || pair->priv)
                        continue;

                if (pair->start == mem_start) {
                        pair->priv = 1;
                        pr_info(" %" PRIx64 "-%" PRIx64 " %" PRIx64 " %s in kallsyms as",
                                map->start, map->end, map->pgoff, map->dso->name);
                        if (mem_end != pair->end)
                                pr_info(":\n*%" PRIx64 "-%" PRIx64 " %" PRIx64,
                                        pair->start, pair->end, pair->pgoff);
                        pr_info(" %s\n", pair->dso->name);
                        pair->priv = 1;
                }
        }

        pr_info("Maps only in kallsyms:\n");

        maps = &kallsyms.kmaps.maps[type];

        for (map = maps__first(maps); map; map = map__next(map)) {
                if (!map->priv)
                        map__fprintf(map, stderr);
        }
out:
        machine__exit(&kallsyms);
        machine__exit(&vmlinux);
        return err;
}