Prep 1.27

[dwarves.git] / ctracer.c

/*
  SPDX-License-Identifier: GPL-2.0-only

  Copyright (C) 2006 Mandriva Conectiva S.A.
  Copyright (C) 2006 Arnaldo Carvalho de Melo <acme@mandriva.com>
*/

#include <argp.h>
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <gelf.h>
#include <limits.h>
#include <search.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

#include "dwarves_reorganize.h"
#include "dwarves_emit.h"
#include "dwarves.h"
#include "dutil.h"
#include "elf_symtab.h"

/*
 * target class name
 */
static char *class_name;

/*
 * List of compilation units being looked for functions with
 * pointers to the specified struct.
 */
static struct cus *methods_cus;

/**
 * Mini class, the subset of the traced class that is collected at the probes
 */

static struct class *mini_class;

/*
 * Directory where to generate source files
 */
static const char *src_dir = ".";

/*
 * Where to print the ctracer_methods.stp file
 */
static FILE *fp_methods;

/*
 * Where to print the ctracer_collector.c file
 */
static FILE *fp_collector;

/*
 * Where to print the ctracer_classes.h file
 */
static FILE *fp_classes;

/*
 * blacklist __init marked functions, i.e. functions that are
 * in the ".init.text" ELF section and are thus discarded after
 * boot.
 */
static struct strlist *init_blacklist;

/*
 * List of definitions and forward declarations already emitted for
 * methods_cus, to avoid duplication.
 */
static struct type_emissions emissions;

/*
 * CU blacklist: if a "blacklist.cu" file is present, don't consider the
 * CUs listed. Use a default of blacklist.cu.
 */
static const char *cu_blacklist_filename = "blacklist.cu";

static struct strlist *cu_blacklist;

static struct cu *cu_filter(struct cu *cu)
{
        if (strlist__has_entry(cu_blacklist, cu->name))
                return NULL;
        return cu;
}

/*
 * List of probes and kretprobes already emitted, this is a hack to cope with
 * name space collisions, a better solution would be to in these cases to use the
 * compilation unit name (net/ipv4/tcp.o, for instance) as a prefix when a
 * static function has the same name in multiple compilation units (aka object
 * files).
 */
static void *probes_emitted;

struct structure {
        struct list_head  node;
        struct tag        *class;
        struct cu         *cu;
};

static struct structure *structure__new(struct tag *class, struct cu *cu)
{
        struct structure *st = malloc(sizeof(*st));

        if (st != NULL) {
                st->class = class;
                st->cu    = cu;
        }

        return st;
}

/*
 * structs that can be casted to the target class, e.g. i.e. that has the target
 * class at its first member.
 */
static LIST_HEAD(aliases);

/*
 * structs have pointers to the target class.
 */
static LIST_HEAD(pointers);

static const char *structure__name(const struct structure *st)
{
        return class__name(tag__class(st->class));
}

static struct structure *structures__find(struct list_head *list, const char *name)
{
        struct structure *pos;

        if (name == NULL)
                return NULL;

        list_for_each_entry(pos, list, node)
                if (strcmp(structure__name(pos), name) == 0)
                        return pos;

        return NULL;
}

static void structures__add(struct list_head *list, struct tag *class, struct cu *cu)
{
        struct structure *str = structure__new(class, cu);

        if (str != NULL)
                list_add(&str->node, list);
}

static int methods__compare(const void *a, const void *b)
{
        return strcmp(a, b);
}

static int methods__add(void **table, const char *str)
{
        char **s = tsearch(str, table, methods__compare);

        if (s != NULL) {
                if (*s == str) {
                        char *dup = strdup(str);
                        if (dup != NULL)
                                *s = dup;
                        else {
                                tdelete(str, table, methods__compare);
                                return -1;
                        }
                } else
                        return -1;
        } else
                return -1;

        return 0;
}

static void method__add(struct cu *cu, struct function *function, uint32_t id)
{
        list_add(&function->tool_node, &cu->tool_list);
        function->priv = (void *)(long)id;
}

/*
 * We want just the function tags that have as one of its parameters
 * a pointer to the specified "class" (a struct, unions can be added later).
 */
static struct function *function__filter(struct function *function,
                                         struct cu *cu, type_id_t target_type_id)
{
        if (function__inlined(function) ||
            function->abstract_origin != 0 ||
            !list_empty(&function->tool_node) ||
            !ftype__has_parm_of_type(&function->proto, target_type_id, cu) ||
            strlist__has_entry(init_blacklist, function__name(function))) {
                return NULL;
        }

        return function;
}

/*
 * Iterate thru all the tags in the compilation unit, looking just for the
 * function tags that have as one of its parameters a pointer to
 * the specified "class" (struct).
 */
static int cu_find_methods_iterator(struct cu *cu, void *cookie)
{
        type_id_t target_type_id;
        uint32_t function_id;
        struct function *function;
        struct tag *target = cu__find_struct_by_name(cu, cookie, 0,
                                                     &target_type_id);

        INIT_LIST_HEAD(&cu->tool_list);

        if (target == NULL)
                return 0;

        cu__for_each_function(cu, function_id, function)
                if (function__filter(function, cu, target_type_id))
                        method__add(cu, function, function_id);

        return 0;
}

static struct class_member *class_member__bitfield_tail(struct class_member *head,
                                                        struct class *class)
{
        struct class_member *tail = head,
                            *member = list_prepare_entry(head,
                                                         class__tags(class),
                                                         tag.node);
        list_for_each_entry_continue(member, class__tags(class), tag.node)
                if (member->byte_offset == head->byte_offset)
                        tail = member;
                else
                        break;

        return tail;
}

/*
 * Bitfields are removed as one for simplification right now.
 */
static struct class_member *class__remove_member(struct class *class, const struct cu *cu,
                                                 struct class_member *member)
{
        size_t size = member->byte_size;
        struct class_member *bitfield_tail = NULL;
        struct list_head *next;
        uint16_t member_hole = member->hole;

        if (member->bitfield_size != 0) {
                bitfield_tail = class_member__bitfield_tail(member, class);
                member_hole = bitfield_tail->hole;
        }
        /*
         * Is this the first member?
         */
        if (member->tag.node.prev == class__tags(class)) {
                class->type.size -= size + member_hole;
                class__subtract_offsets_from(class, bitfield_tail ?: member,
                                             size + member_hole);
        /*
         * Is this the last member?
         */
        } else if (member->tag.node.next == class__tags(class)) {
                if (size + class->padding >= cu->addr_size) {
                        class->type.size -= size + class->padding;
                        class->padding = 0;
                } else
                        class->padding += size;
        } else {
                if (size + member_hole >= cu->addr_size) {
                        class->type.size -= size + member_hole;
                        class__subtract_offsets_from(class,
                                                     bitfield_tail ?: member,
                                                     size + member_hole);
                } else {
                        struct class_member *from_prev =
                                        list_entry(member->tag.node.prev,
                                                   struct class_member,
                                                   tag.node);
                        if (from_prev->hole == 0)
                                class->nr_holes++;
                        from_prev->hole += size + member_hole;
                }
        }
        if (member_hole != 0)
                class->nr_holes--;

        if (bitfield_tail != NULL) {
                next = bitfield_tail->tag.node.next;
                list_del_range(&member->tag.node, &bitfield_tail->tag.node);
                if (bitfield_tail->bit_hole != 0)
                        class->nr_bit_holes--;
        } else {
                next = member->tag.node.next;
                list_del(&member->tag.node);
        }

        return list_entry(next, struct class_member, tag.node);
}

static size_t class__find_biggest_member_name(const struct class *class)
{
        struct class_member *pos;
        size_t biggest_name_len = 0;

        type__for_each_data_member(&class->type, pos) {
                const size_t len = pos->name ?
                                        strlen(class_member__name(pos)) : 0;

                if (len > biggest_name_len)
                        biggest_name_len = len;
        }

        return biggest_name_len;
}

static void class__emit_class_state_collector(struct class *class, struct class *clone)
{
        struct class_member *pos;
        int len = class__find_biggest_member_name(clone);

        fprintf(fp_collector,
                "void ctracer__class_state(const void *from, void *to)\n"
                "{\n"
                "\tconst struct %s *obj = from;\n"
                "\tstruct %s *mini_obj = to;\n\n",
                class__name(class), class__name(clone));
        type__for_each_data_member(&clone->type, pos)
                fprintf(fp_collector, "\tmini_obj->%-*s = obj->%s;\n", len,
                        class_member__name(pos),
                        class_member__name(pos));
        fputs("}\n\n", fp_collector);
}

static struct class *class__clone_base_types(const struct tag *tag,
                                             struct cu *cu,
                                             const char *new_class_name)
{
        struct class *class = tag__class(tag);
        struct class_member *pos, *next;
        struct class *clone = class__clone(class, new_class_name);

        if (clone == NULL)
                return NULL;

        type__for_each_data_member_safe(&clone->type, pos, next) {
                struct tag *member_type = cu__type(cu, pos->tag.type);

                tag__assert_search_result(member_type, pos->tag.tag, class_member__name(pos));
                if (!tag__is_base_type(member_type, cu)) {
                        next = class__remove_member(clone, cu, pos);
                        class_member__delete(pos);
                }
        }
        class__fixup_alignment(clone, cu);
        class__reorganize(clone, cu, 0, NULL);
        return clone;
}

/**
 * Converter to the legacy ostra tables, will be much improved in the future.
 */
static void emit_struct_member_table_entry(FILE *fp,
                                           int field, const char *name,
                                           int traced, const char *hooks)
{
        fprintf(fp, "%u:%s:", field, name);
        if (traced)
                fprintf(fp, "yes:%%object->%s:u:%s:none\n", name, hooks);
        else
                fprintf(fp, "no:None:None:%s:dev_null\n", hooks);
}

/**
 * Generates a converter to the ostra lebacy tables format, needef by
 * ostra-cg to preprocess the raw data collected from the debugfs/relay
 * channel.
 */
static int class__emit_ostra_converter(struct tag *tag)
{
        struct class *class = tag__class(tag);
        struct class_member *pos;
        struct type *type = &mini_class->type;
        int field = 0, first = 1;
        char filename[128];
        char parm_list[1024] = "";
        char *p = parm_list;
        size_t n;
        size_t plen = sizeof(parm_list);
        FILE *fp_fields, *fp_converter;
        const char *name = class__name(class);

        snprintf(filename, sizeof(filename), "%s/%s.fields", src_dir, name);
        fp_fields = fopen(filename, "w");
        if (fp_fields == NULL) {
                fprintf(stderr, "ctracer: couldn't create %s\n", filename);
                exit(EXIT_FAILURE);
        }

        snprintf(filename, sizeof(filename), "%s/ctracer2ostra.c", src_dir);

        fp_converter = fopen(filename, "w");
        if (fp_converter == NULL) {
                fprintf(stderr, "ctracer: couldn't create %s\n", filename);
                exit(EXIT_FAILURE);
        }

        fputs("#include \"ctracer_classes.h\"\n"
              "#include <stdio.h>\n"
              "#include <string.h>\n"
              "#include \"ctracer_relay.h\"\n\n", fp_converter);
        emit_struct_member_table_entry(fp_fields, field++, "action", 0,
                                       "entry,exit");
        emit_struct_member_table_entry(fp_fields, field++, "function_id", 0,
                                       "entry,exit");
        emit_struct_member_table_entry(fp_fields, field++, "object", 1,
                                       "entry,exit");

        fprintf(fp_converter, "\n"
              "int main(void)\n"
              "{\n"
              "\twhile (1) {\n"
              "\t\tstruct trace_entry hdr;\n"
              "\t\tstruct ctracer__mini_%s obj;\n"
              "\n"
              "\t\tif (read(0, &hdr, sizeof(hdr)) != sizeof(hdr))\n"
              "\t\t\tbreak;\n"
              "\n"
              "\t\tfprintf(stdout, \"%%llu %%c:%%llu:%%p\",\n"
              "\t\t\thdr.nsec,\n"
              "\t\t\thdr.probe_type ? 'o' : 'i',\n"
              "\t\t\thdr.function_id,\n"
              "\t\t\thdr.object);\n"
              "\n"
              "\t\tif (read(0, &obj, sizeof(obj)) != sizeof(obj))\n"
              "\t\t\tbreak;\n"
              "\t\tfprintf(stdout,\n"
              "\t\t\t\":", name);

        type__for_each_data_member(type, pos) {
                if (first)
                        first = 0;
                else {
                        fputc(':', fp_converter);
                        n = snprintf(p, plen, ",\n\t\t\t ");
                        plen -= n; p += n;
                }
                fprintf(fp_converter, "%%u");
                n = snprintf(p, plen, "obj.%s", class_member__name(pos));
                plen -= n; p += n;
                emit_struct_member_table_entry(fp_fields, field++,
                                               class_member__name(pos),
                                               1, "entry,exit");
        }
        fprintf(fp_converter,
                "\\n\",\n\t\t\t %s);\n"
                "\t}\n"
                "\treturn 0;\n"
                "}\n", parm_list);
        fclose(fp_fields);
        fclose(fp_converter);
        return 0;
}

/*
 * We want just the DW_TAG_structure_type tags that have a member that is a pointer
 * to the target class.
 */
static struct tag *pointer_filter(struct tag *tag, struct cu *cu,
                                  type_id_t target_type_id)
{
        struct type *type;
        struct class_member *pos;
        const char *class_name;

        if (!tag__is_struct(tag))
                return NULL;

        type = tag__type(tag);
        if (type->nr_members == 0)
                return NULL;

        class_name = class__name(tag__class(tag));
        if (class_name == NULL || structures__find(&pointers, class_name))
                return NULL;

        type__for_each_member(type, pos) {
                struct tag *ctype = cu__type(cu, pos->tag.type);

                tag__assert_search_result(ctype, pos->tag.tag, class_member__name(pos));
                if (tag__is_pointer_to(ctype, target_type_id))
                        return tag;
        }

        return NULL;
}

/*
 * Iterate thru all the tags in the compilation unit, looking for classes
 * that have as one member that is a pointer to the target type.
 */
static int cu_find_pointers_iterator(struct cu *cu, void *class_name)
{
        type_id_t target_type_id, id;
        struct tag *target = cu__find_struct_by_name(cu, class_name, 0,
                                                     &target_type_id), *pos;

        if (target == NULL)
                return 0;

        cu__for_each_type(cu, id, pos)
                if (pointer_filter(pos, cu, target_type_id))
                        structures__add(&pointers, pos, cu);

        return 0;
}

static void class__find_pointers(const char *class_name)
{
        cus__for_each_cu(methods_cus, cu_find_pointers_iterator, (void *)class_name, cu_filter);
}

/*
 * We want just the DW_TAG_structure_type tags that have as its first member
 * a struct of type target.
 */
static struct tag *alias_filter(struct tag *tag, type_id_t target_type_id)
{
        struct type *type;
        struct class_member *first_member;

        if (!tag__is_struct(tag))
                return NULL;

        type = tag__type(tag);
        if (type->nr_members == 0)
                return NULL;

        first_member = list_first_entry(&type->namespace.tags,
                                        struct class_member, tag.node);
        if (first_member->tag.type != target_type_id)
                return NULL;

        if (structures__find(&aliases, class__name(tag__class(tag))))
                return NULL;

        return tag;
}

static void class__find_aliases(const char *class_name);

/*
 * Iterate thru all the tags in the compilation unit, looking for classes
 * that have as its first member the specified "class" (struct).
 */
static int cu_find_aliases_iterator(struct cu *cu, void *class_name)
{
        type_id_t target_type_id, id;
        struct tag *target = cu__find_struct_by_name(cu, class_name, 0,
                                                     &target_type_id), *pos;
        if (target == NULL)
                return 0;

        cu__for_each_type(cu, id, pos) {
                if (alias_filter(pos, target_type_id)) {
                        const char *alias_name = class__name(tag__class(pos));

                        structures__add(&aliases, pos, cu);

                        /*
                         * Now find aliases to this alias, e.g.:
                         *
                         * struct tcp_sock {
                         *      struct inet_connection_sock {
                         *              struct inet_sock {
                         *                      struct sock {
                         *                      }
                         *              }
                         *      }
                         * }
                         */
                        class__find_aliases(alias_name);
                }
        }

        return 0;
}

static void class__find_aliases(const char *class_name)
{
        cus__for_each_cu(methods_cus, cu_find_aliases_iterator, (void *)class_name, cu_filter);
}

static void emit_list_of_types(struct list_head *list)
{
        struct structure *pos;

        list_for_each_entry(pos, list, node) {
                struct type *type = tag__type(pos->class);
                /*
                 * Lets look at the other CUs, perhaps we have already
                 * emmited this one
                 */
                if (type_emissions__find_definition(&emissions, type__tag(type)->tag, structure__name(pos))) {
                        type->definition_emitted = 1;
                        continue;
                }
                type__emit_definitions(pos->class, pos->cu, &emissions,
                                       fp_classes);
                type->definition_emitted = 1;
                type__emit(pos->class, pos->cu, NULL, NULL, fp_classes);
                tag__type(pos->class)->definition_emitted = 1;
                fputc('\n', fp_classes);
        }
}

static int class__emit_classes(struct tag *tag, struct cu *cu)
{
        struct class *class = tag__class(tag);
        int err = -1;
        char mini_class_name[128];

        snprintf(mini_class_name, sizeof(mini_class_name), "ctracer__mini_%s",
                 class__name(class));

        mini_class = class__clone_base_types(tag, cu, mini_class_name);
        if (mini_class == NULL)
                goto out;

        type__emit_definitions(tag, cu, &emissions, fp_classes);

        type__emit(tag, cu, NULL, NULL, fp_classes);
        fputs("\n/* class aliases */\n\n", fp_classes);

        emit_list_of_types(&aliases);

        fputs("\n/* class with pointers */\n\n", fp_classes);

        emit_list_of_types(&pointers);

        class__fprintf(mini_class, cu, fp_classes);
        fputs(";\n\n", fp_classes);
        class__emit_class_state_collector(class, mini_class);
        err = 0;
out:
        return err;
}

/*
 * Emit the kprobes routine for one of the selected "methods", later we'll
 * put this into the 'kprobes' table, in cu_emit_kprobes_table_iterator.
 *
 * This marks the function entry, function__emit_kretprobes will emit the
 * probe for the function exit.
 */
static int function__emit_probes(struct function *func, uint32_t function_id,
                                 const struct cu *cu,
                                 const type_id_t target_type_id, int probe_type,
                                 const char *member)
{
        struct parameter *pos;
        const char *name = function__name(func);

        fprintf(fp_methods, "probe %s%s = kernel.function(\"%s@%s\")%s\n"
                            "{\n"
                            "}\n\n"
                            "probe %s%s\n"
                            "{\n", name,
                            probe_type == 0 ? "" : "__return",
                            name,
                            cu->name,
                            probe_type == 0 ? "" : ".return",
                            name,
                            probe_type == 0 ? "" : "__return");

        list_for_each_entry(pos, &func->proto.parms, tag.node) {
                struct tag *type = cu__type(cu, pos->tag.type);

                tag__assert_search_result(type, pos->tag.tag, parameter__name(pos));
                if (!tag__is_pointer_to(type, target_type_id))
                        continue;

                if (member != NULL)
                        fprintf(fp_methods, "\tif ($%s)\n\t", parameter__name(pos));

                fprintf(fp_methods,
                        "\tctracer__method_hook(%d, %d, $%s%s%s, %d);\n",
                        probe_type,
                        function_id,
                        parameter__name(pos),
                        member ? "->" : "", member ?: "",
                        class__size(mini_class));
                break;
        }

        fputs("}\n\n", fp_methods);
        fflush(fp_methods);

        return 0;
}

/*
 * Iterate thru the list of methods previously collected by
 * cu_find_methods_iterator, emitting the probes for function entry.
 */
static int cu_emit_probes_iterator(struct cu *cu, void *cookie)
{
        type_id_t target_type_id;
        struct tag *target = cu__find_struct_by_name(cu, cookie, 0, &target_type_id);
        struct function *pos;

        /* OK, this type is not present in this compile unit */
        if (target == NULL)
                return 0;

        list_for_each_entry(pos, &cu->tool_list, tool_node) {
                uint32_t function_id = (long)pos->priv;

                if (methods__add(&probes_emitted, function__name(pos)) != 0)
                        continue;
                function__emit_probes(pos, function_id, cu, target_type_id, 0, NULL); /* entry */
                function__emit_probes(pos, function_id, cu, target_type_id, 1, NULL); /* exit */
        }

        return 0;
}

/*
 * Iterate thru the list of methods previously collected by
 * cu_find_methods_iterator, emitting the probes for function entry.
 */
static int cu_emit_pointer_probes_iterator(struct cu *cu, void *cookie)
{
        type_id_t target_type_id, pointer_id;
        struct tag *target, *pointer;
        struct function *pos_tag;
        struct class_member *pos_member;

        /* This CU doesn't have our classes */
        if (list_empty(&cu->tool_list))
                return 0;

        target = cu__find_struct_by_name(cu, class_name, 1, &target_type_id);
        pointer = cu__find_struct_by_name(cu, cookie, 0, &pointer_id);

        /* OK, this type is not present in this compile unit */
        if (target == NULL || pointer == NULL)
                return 0;

        /* for now just for the first member that is a pointer */
        type__for_each_member(tag__type(pointer), pos_member) {
                struct tag *ctype = cu__type(cu, pos_member->tag.type);

                tag__assert_search_result(ctype, pos_member->tag.tag, class_member__name(pos_member));
                if (tag__is_pointer_to(ctype, target_type_id))
                        break;
        }

        list_for_each_entry(pos_tag, &cu->tool_list, tool_node) {
                uint32_t function_id = (long)pos_tag->priv;

                if (methods__add(&probes_emitted, function__name(pos_tag)) != 0)
                        continue;

                function__emit_probes(pos_tag, function_id, cu, target_type_id, 0,
                                      class_member__name(pos_member)); /* entry */
                function__emit_probes(pos_tag, function_id, cu, target_type_id, 1,
                                      class_member__name(pos_member)); /* exit */
        }

        return 0;
}

/*
 * Iterate thru the list of methods previously collected by
 * cu_find_methods_iterator, creating the functions table that will
 * be used by ostra-cg
 */
static int cu_emit_functions_table(struct cu *cu, void *fp)
{
       struct function *pos;

       list_for_each_entry(pos, &cu->tool_list, tool_node)
               if (pos->priv != NULL) {
                        uint32_t function_id = (long)pos->priv;
                        fprintf(fp, "%d:%s\n", function_id, function__name(pos));
                        pos->priv = NULL;
                }

       return 0;
}

static int elf__open(const char *filename)
{
        int fd = open(filename, O_RDONLY);

        if (fd < 0)
                return -1;

        int err = -1;

        if (elf_version(EV_CURRENT) == EV_NONE) {
                fprintf(stderr, "%s: cannot set libelf version.\n", __func__);
                goto out_close;
        }

        Elf *elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
        if (elf == NULL) {
                fprintf(stderr, "%s: cannot read %s ELF file.\n",
                        __func__, filename);
                goto out_close;
        }

        GElf_Shdr shdr;
        size_t init_index;
        Elf_Scn *init = elf_section_by_name(elf, &shdr, ".init.text", &init_index);
        if (init == NULL)
                goto out_elf_end;

        struct elf_symtab *symtab = elf_symtab__new(".symtab", elf);
        if (symtab == NULL)
                goto out_elf_end;

        init_blacklist = strlist__new(true);
        if (init_blacklist == NULL)
                goto out_elf_symtab_delete;

        uint32_t index;
        GElf_Sym sym;
        elf_symtab__for_each_symbol(symtab, index, sym) {
                if (!elf_sym__is_local_function(&sym))
                        continue;
                if (elf_sym__section(&sym) != init_index)
                        continue;
                err = strlist__add(init_blacklist, elf_sym__name(&sym, symtab));
                if (err == -ENOMEM) {
                        fprintf(stderr, "failed for %s(%d,%zd)\n", elf_sym__name(&sym, symtab),elf_sym__section(&sym),init_index);
                        goto out_delete_blacklist;
                }
        }

        err = 0;
out_elf_symtab_delete:
        elf_symtab__delete(symtab);
out_elf_end:
        elf_end(elf);
out_close:
        close(fd);
        return err;
out_delete_blacklist:
        strlist__delete(init_blacklist);
        goto out_elf_symtab_delete;
}

/* Name and version of program.  */
ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;

static const struct argp_option ctracer__options[] = {
        {
                .key  = 'd',
                .name = "src_dir",
                .arg  = "SRC_DIR",
                .doc  = "generate source files in this directory",
        },
        {
                .key  = 'C',
                .name = "cu_blacklist",
                .arg  = "FILE",
                .doc  = "Blacklist the CUs in FILE",
        },
        {
                .key  = 'D',
                .name = "dir",
                .arg  = "DIR",
                .doc  = "load files in this directory",
        },
        {
                .key  = 'g',
                .name = "glob",
                .arg  = "GLOB",
                .doc  = "file mask to load",
        },
        {
                .key  = 'r',
                .name = "recursive",
                .doc  = "recursively load files",
        },
        {
                .name = NULL,
        }
};

static const char *dirname, *glob;
static int recursive;

static error_t ctracer__options_parser(int key, char *arg,
                                      struct argp_state *state __maybe_unused)
{
        switch (key) {
        case 'd': src_dir = arg;                break;
        case 'C': cu_blacklist_filename = arg;  break;
        case 'D': dirname = arg;                break;
        case 'g': glob = arg;                   break;
        case 'r': recursive = 1;                break;
        default:  return ARGP_ERR_UNKNOWN;
        }
        return 0;
}

static const char ctracer__args_doc[] = "FILE CLASS";

static struct argp ctracer__argp = {
        .options  = ctracer__options,
        .parser   = ctracer__options_parser,
        .args_doc = ctracer__args_doc,
};

int main(int argc, char *argv[])
{
        int remaining, err;
        struct tag *class;
        struct cu *cu;
        char *filename;
        char functions_filename[PATH_MAX];
        char methods_filename[PATH_MAX];
        char collector_filename[PATH_MAX];
        char classes_filename[PATH_MAX];
        struct structure *pos;
        FILE *fp_functions;
        int rc = EXIT_FAILURE;

        if (dwarves__init()) {
                fputs("ctracer: insufficient memory\n", stderr);
                goto out;
        }
        dwarves__resolve_cacheline_size(NULL, 0);

        if (argp_parse(&ctracer__argp, argc, argv, 0, &remaining, NULL) ||
            remaining < argc) {
                switch (argc - remaining) {
                case 1:  goto failure;
                case 2:  filename  = argv[remaining++];
                         class_name = argv[remaining++];        break;
                default: goto failure;
                }
        } else {
failure:
                argp_help(&ctracer__argp, stderr, ARGP_HELP_SEE, argv[0]);
                goto out;
        }

        type_emissions__init(&emissions, NULL);

        /*
         * Create the methods_cus (Compilation Units) object where we will
         * load the objects where we'll look for functions pointers to the
         * specified class, i.e. to find its "methods", where we'll insert
         * the entry and exit hooks.
         */
        methods_cus = cus__new();
        if (methods_cus == NULL) {
                fputs("ctracer: insufficient memory\n", stderr);
                goto out;
        }

        /*
         * if --dir/-D was specified, recursively traverse the path looking for
         * object files (compilation units) that match the glob specified (*.ko)
         * for kernel modules, but could be "*.o" in the future when we support
         * uprobes for user space tracing.
         */
        if (dirname != NULL && cus__load_dir(methods_cus, NULL, dirname, glob,
                                             recursive) != 0) {
                fprintf(stderr, "ctracer: couldn't load DWARF info "
                                "from %s dir with glob %s\n",
                        dirname, glob);
                goto out;
        }

        /*
         * If a filename was specified, for instance "vmlinux", load it too.
         */
        if (filename != NULL) {
                if (elf__open(filename)) {
                        fprintf(stderr, "ctracer: couldn't load ELF symtab "
                                        "info from %s\n", filename);
                        goto out;
                }
                err = cus__load_file(methods_cus, NULL, filename);
                if (err != 0) {
                        cus__print_error_msg("ctracer", methods_cus, filename, err);
                        goto out;
                }
        }

        /*
         * See if the specified struct exists:
         */
        class = cus__find_struct_by_name(methods_cus, &cu, class_name, 0, NULL);
        if (class == NULL) {
                fprintf(stderr, "ctracer: struct %s not found!\n", class_name);
                goto out;
        }

        snprintf(functions_filename, sizeof(functions_filename),
                 "%s/%s.functions", src_dir, class__name(tag__class(class)));
        fp_functions = fopen(functions_filename, "w");
        if (fp_functions == NULL) {
                fprintf(stderr, "ctracer: couldn't create %s\n",
                        functions_filename);
                goto out;
        }

        snprintf(methods_filename, sizeof(methods_filename),
                 "%s/ctracer_methods.stp", src_dir);
        fp_methods = fopen(methods_filename, "w");
        if (fp_methods == NULL) {
                fprintf(stderr, "ctracer: couldn't create %s\n",
                        methods_filename);
                goto out;
        }

        snprintf(collector_filename, sizeof(collector_filename),
                 "%s/ctracer_collector.c", src_dir);
        fp_collector = fopen(collector_filename, "w");
        if (fp_collector == NULL) {
                fprintf(stderr, "ctracer: couldn't create %s\n",
                        collector_filename);
                goto out;
        }

        snprintf(classes_filename, sizeof(classes_filename),
                 "%s/ctracer_classes.h", src_dir);
        fp_classes = fopen(classes_filename, "w");
        if (fp_classes == NULL) {
                fprintf(stderr, "ctracer: couldn't create %s\n",
                        classes_filename);
                goto out;
        }

        fputs("%{\n"
              "#include </home/acme/git/pahole/lib/ctracer_relay.h>\n"
              "%}\n"
              "function ctracer__method_hook(probe_type, func, object, state_len)\n"
              "%{\n"
              "\tctracer__method_hook(_stp_gettimeofday_ns(), "
                                     "THIS->probe_type, THIS->func, "
                                     "(void *)(long)THIS->object, "
                                     "THIS->state_len);\n"
              "%}\n\n", fp_methods);

        fputs("\n#include \"ctracer_classes.h\"\n\n", fp_collector);
        class__find_aliases(class_name);
        class__find_pointers(class_name);

        class__emit_classes(class, cu);
        fputc('\n', fp_collector);

        class__emit_ostra_converter(class);

        cu_blacklist = strlist__new(true);
        if (cu_blacklist != NULL)
                strlist__load(cu_blacklist, cu_blacklist_filename);

        cus__for_each_cu(methods_cus, cu_find_methods_iterator,
                         class_name, cu_filter);
        cus__for_each_cu(methods_cus, cu_emit_probes_iterator,
                         class_name, cu_filter);
        cus__for_each_cu(methods_cus, cu_emit_functions_table,
                         fp_functions, cu_filter);

        list_for_each_entry(pos, &aliases, node) {
                const char *alias_name = structure__name(pos);

                cus__for_each_cu(methods_cus, cu_find_methods_iterator,
                                 (void *)alias_name, cu_filter);
                cus__for_each_cu(methods_cus, cu_emit_probes_iterator,
                                 (void *)alias_name, cu_filter);
                cus__for_each_cu(methods_cus, cu_emit_functions_table,
                                 fp_functions, cu_filter);
        }

        list_for_each_entry(pos, &pointers, node) {
                const char *pointer_name = structure__name(pos);
                cus__for_each_cu(methods_cus, cu_find_methods_iterator,
                                 (void *)pointer_name, cu_filter);
                cus__for_each_cu(methods_cus, cu_emit_pointer_probes_iterator,
                                 (void *)pointer_name, cu_filter);
                cus__for_each_cu(methods_cus, cu_emit_functions_table, fp_functions,
                                 cu_filter);
        }

        fclose(fp_methods);
        fclose(fp_collector);
        fclose(fp_functions);
        fclose(fp_classes);
        strlist__delete(cu_blacklist);

        rc = EXIT_SUCCESS;
out:
        cus__delete(methods_cus);
        dwarves__exit();
        return rc;
}