dwarves/ctracer.c
Arnaldo Carvalho de Melo b7cd0b6fdf [CTRACER]: Convert to argp
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
2007-03-30 11:16:50 -03:00

796 lines
22 KiB
C

/*
Copyright (C) 2006 Mandriva Conectiva S.A.
Copyright (C) 2006 Arnaldo Carvalho de Melo <acme@mandriva.com>
This program is free software; you can redistribute it and/or modify it
under the terms of version 2 of the GNU General Public License as
published by the Free Software Foundation.
*/
#include <argp.h>
#include <limits.h>
#include <search.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include "dwarves.h"
/*
* List of compilation units being looked for functions with
* pointers to the specified struct.
*/
static struct cus *methods_cus;
/**
* Compilation units with the definitions for the kprobes functions and struct
* definitions for the, can point to methods_cus if those definitions are
* available there (example: when using 'ctracer vmlinux sk_buff', vmlinux
* will have the sk_buff "methods" and the kprobes "classes" and "methods".
*/
static struct cus *kprobes_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.c file
*/
static FILE *fp_methods;
/*
* List of definitions and forward declarations already emitted for
* methods_cus and kprobes_cus, to avoid duplication.
*/
static LIST_HEAD(cus__definitions);
static LIST_HEAD(cus__fwd_decls);
/*
* List of jprobes 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 *jprobes_emitted;
static void *kretprobes_emitted;
static int methods__compare(const void *a, const void *b)
{
return strcmp(a, b);
}
/*
* Add a method to jprobes_emitted or kretprobes_emitted, see comment above.
*/
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)
{
list_add(&function->tool_node, &cu->tool_list);
}
/*
* We want just the DW_TAG_subprogram tags that have as one of its parameters
* a pointer to the specified "class" (a struct, unions can be added later).
*/
static struct tag *function__filter(struct tag *tag, struct cu *cu, void *cookie)
{
struct function *function;
if (tag->tag != DW_TAG_subprogram)
return NULL;
function = tag__function(tag);
if (function__inlined(function) ||
function->abstract_origin != 0 ||
!ftype__has_parm_of_type(&function->proto, cookie, cu))
return NULL;
return tag;
}
/*
* Add the function to the list of methods since it matches function__filter
* criteria.
*/
static int find_methods_iterator(struct tag *tag, struct cu *cu,
void *cookie __unused)
{
struct function *function = tag__function(tag);
method__add(cu, function);
return 0;
}
/*
* Iterate thru all the tags in the compilation unit, looking just for the
* DW_TAG_subprogram 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)
{
struct tag *target = cu__find_struct_by_name(cu, cookie);
if (target == NULL)
return 0;
return cu__for_each_tag(cu, find_methods_iterator, target, function__filter);
}
static void class__remove_member(struct class *self, const struct cu *cu,
struct class_member *member)
{
const size_t size = class_member__size(member, cu);
/*
* Is this the first member?
*/
if (member->tag.node.prev == &self->type.members) {
self->type.size -= size;
class__subtract_offsets_from(self, cu, member, size);
} else {
struct class_member *from_prev =
list_entry(member->tag.node.prev,
struct class_member, tag.node);
if (member->hole + size >= cu->addr_size) {
self->type.size -= size + member->hole;
class__subtract_offsets_from(self, cu, member,
size + member->hole);
} else
from_prev->hole += size + member->hole;
}
if (member->hole != 0)
self->nr_holes--;
list_del(&member->tag.node);
class_member__delete(member);
}
static size_t class__find_biggest_member_name(const struct class *self)
{
struct class_member *pos;
size_t biggest_name_len = 0;
list_for_each_entry(pos, &self->type.members, tag.node) {
const size_t len = strlen(pos->name);
if (len > biggest_name_len)
biggest_name_len = len;
}
return biggest_name_len;
}
static void class__emit_class_state_collector(const struct class *self,
const struct class *clone)
{
struct class_member *pos;
int len = class__find_biggest_member_name(clone);
fprintf(fp_methods,
"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(self), class__name(clone));
list_for_each_entry(pos, &clone->type.members, tag.node) {
fprintf(fp_methods, "\tmini_obj->%-*s = obj->%s;\n",
len, pos->name, pos->name);
}
fputs("}\n\n", fp_methods);
}
static struct class *class__clone_base_types(const struct tag *tag_self,
const struct cu *cu,
const char *new_class_name)
{
struct class *self = tag__class(tag_self);
struct class_member *pos, *next;
struct class *clone = class__clone(self, new_class_name);
if (clone == NULL)
return NULL;
class__find_holes(clone, cu);
list_for_each_entry_safe(pos, next, &clone->type.members, tag.node) {
struct tag *member_type = cu__find_tag_by_id(cu, pos->tag.type);
if (member_type->tag != DW_TAG_base_type)
class__remove_member(clone, cu, pos);
}
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(const struct tag *tag_self,
const struct cu *cu)
{
const struct class *self = tag__class(tag_self);
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;
snprintf(filename, sizeof(filename), "%s/%s.fields",
src_dir, class__name(self));
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 <stdio.h>\n"
"#include <string.h>\n"
"#include \"ctracer_relay.h\"\n\n", fp_converter);
class__fprintf(mini_class, cu, NULL, NULL, 0, 0, 26, 23, 1,
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");
fputs("\n"
"int main(void)\n"
"{\n"
"\twhile (1) {\n"
"\t\tstruct trace_entry hdr;\n"
"\t\tstruct ctracer__mini_sock obj;\n"
"\n"
"\t\tif (read(0, &hdr, sizeof(hdr)) != sizeof(hdr))\n"
"\t\t\tbreak;\n"
"\n"
"\t\tfprintf(stdout, \"%u.%06u %c:%llu:%p\",\n"
"\t\t\thdr.sec, hdr.usec,\n"
"\t\t\thdr.probe_type ? 'o' : 'i',\n"
"\t\t\thdr.function_id,\n"
"\t\t\thdr.object);\n"
"\n"
"\t\tif (hdr.probe_type) {\n"
"\t\t\tfputc('\\n', stdout);\n"
"\t\t\tcontinue;\n"
"\t\t}\n"
"\n"
"\t\tif (read(0, &obj, sizeof(obj)) != sizeof(obj))\n"
"\t\t\tbreak;\n"
"\t\tfprintf(stdout,\n"
"\t\t\t\":",
fp_converter);
list_for_each_entry(pos, &type->members, tag.node) {
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", pos->name);
plen -= n; p += n;
emit_struct_member_table_entry(fp_fields, field++,
pos->name, 1, "entry");
}
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;
}
static int class__emit_subset(const struct tag *tag_self, const struct cu *cu)
{
struct class *self = tag__class(tag_self);
int err = -1;
char mini_class_name[128];
snprintf(mini_class_name, sizeof(mini_class_name), "ctracer__mini_%s",
class__name(self));
mini_class = class__clone_base_types(tag_self, cu, mini_class_name);
if (mini_class == NULL)
goto out;
class__fprintf(mini_class, cu, NULL, NULL, 0, 0, 26, 23, 1,
fp_methods);
fputc('\n', fp_methods);
class__emit_class_state_collector(self, 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_kprobes(struct function *self, const struct cu *cu,
const struct tag *target)
{
char jprobe_name[256];
struct parameter *pos;
const char *name = function__name(self, cu);
fputs("static ", fp_methods);
snprintf(jprobe_name, sizeof(jprobe_name), "jprobe_entry__%s", name);
ftype__fprintf(&self->proto, cu, jprobe_name, 0, 0, 0, fp_methods);
fputs("\n{\n", fp_methods);
list_for_each_entry(pos, &self->proto.parms, tag.node) {
struct tag *type = cu__find_tag_by_id(cu, pos->tag.type);
if (type->tag != DW_TAG_pointer_type)
continue;
type = cu__find_tag_by_id(cu, type->type);
if (type == NULL || type->id != target->id)
continue;
fprintf(fp_methods,
"\tctracer__method_entry(%#llx, %s, %zd);\n",
(unsigned long long)self->proto.tag.id, pos->name,
class__size(mini_class));
break;
}
fprintf(fp_methods, "\tjprobe_return();\n"
"\t/* NOTREACHED */%s\n}\n\n",
self->proto.tag.type != 0 ? "\n\treturn 0;" : "");
fprintf(fp_methods, "static struct jprobe jprobe__%s = {\n"
"\t.kp = { .symbol_name = \"%s\", },\n"
"\t.entry = (kprobe_opcode_t *)jprobe_entry__%s,\n"
"};\n\n", name, name, name);
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_kprobes_iterator(struct cu *cu, void *cookie)
{
struct tag *target = cu__find_struct_by_name(cu, cookie);
struct function *pos;
list_for_each_entry(pos, &cu->tool_list, tool_node) {
if (methods__add(&jprobes_emitted, function__name(pos, cu)) != 0)
continue;
pos->priv = (void *)1; /* Mark as visited, for the table iterator */
cus__emit_ftype_definitions(methods_cus, cu,
&pos->proto, fp_methods);
function__emit_kprobes(pos, cu, target);
}
return 0;
}
/*
* Iterate thru the list of methods previously collected by
* cu_find_methods_iterator, creating the 'kprobes' table, that will
* be used at the module init routine to register the kprobes for function
* entry, and at module exit time to unregister the kprobes.
*/
static int cu_emit_kprobes_table_iterator(struct cu *cu, void *cookie __unused)
{
struct function *pos;
list_for_each_entry(pos, &cu->tool_list, tool_node)
if (pos->priv != NULL) {
const char *name = function__name(pos, cu);
fprintf(fp_methods, "\t&jprobe__%s,\n", name);
fprintf(cookie, "%llu:%s\n",
(unsigned long long)pos->proto.tag.id, name);
}
return 0;
}
/*
* 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 exit.
*
* We still need to get the pointer to the "class instance", i.e. the pointer
* to the specified struct, this will be done using the "data pouch" mentioned
* in the kprobes mailing list, where we at the entry kprobes we store the
* pointer to be used here, or possibly using plain kprobes at the function
* entry and using DW_AT_location to discover where in the stack or in a
* processor register were the parameters for the function.
*/
static void function__emit_kretprobes(struct function *self,
const struct cu *cu)
{
const char *name = function__name(self, cu);
fprintf(fp_methods,
"static int kretprobe_handler__%s(struct kretprobe_instance *ri, "
"struct pt_regs *regs)\n"
"{\n"
"\tctracer__method_exit(%#llx);\n"
"\treturn 0;\n"
"}\n\n", name, (unsigned long long)self->proto.tag.id);
fprintf(fp_methods,
"static struct kretprobe kretprobe__%s = {\n"
"\t.kp = { .symbol_name = \"%s\", },\n"
"\t.handler = (kretprobe_handler_t)kretprobe_handler__%s,\n"
"};\n\n", name, name, name);
}
/*
* Iterate thru the list of methods previously collected by
* cu_find_methods_iterator, emitting the probes for function exit.
*/
static int cu_emit_kretprobes_iterator(struct cu *cu, void *cookie __unused)
{
struct function *pos;
list_for_each_entry(pos, &cu->tool_list, tool_node) {
if (methods__add(&kretprobes_emitted,
function__name(pos, cu)) != 0)
continue;
pos->priv = (void *)1; /* Mark as visited, for the table iterator */
function__emit_kretprobes(pos, cu);
}
return 0;
}
/*
* Iterate thru the list of methods previously collected by
* cu_find_methods_iterator, creating the 'kretprobes' table, that will
* be used at the module init routine to register the kprobes for function
* entry, and at module exit time to unregister the kretprobes.
*/
static int cu_emit_kretprobes_table_iterator(struct cu *cu,
void *cookie __unused)
{
struct function *pos;
list_for_each_entry(pos, &cu->tool_list, tool_node)
if (pos->priv != NULL)
fprintf(fp_methods, "\t&kretprobe__%s,\n",
function__name(pos, cu));
return 0;
}
/*
* Emit a definition for the specified function, looking for it in the
* tags previously collected, cus__emit_ftype_definitions will look at the
* function return type and recursively emit all the definitions needed,
* ditto for all the function parameters, emitting just a forward declaration
* if the parameter is just a pointer, or all of the enums, struct, unions,
* etc that are required for the resulting C source code to be built.
*/
static void emit_function_defs(const char *fn)
{
struct cu *cu;
struct tag *f = cus__find_function_by_name(kprobes_cus, &cu, fn);
if (f != NULL) {
cus__emit_ftype_definitions(kprobes_cus, cu,
&tag__function(f)->proto,
fp_methods);
tag__fprintf(f, cu, NULL, NULL, 0, fp_methods);
fputs(";\n", fp_methods);
}
}
/*
* Emit a struct definition, looking at all the function members and recursively
* emitting its type definitions (enums, structs, unions, etc).
*/
static void emit_struct_defs(const char *name)
{
struct cu *cu;
struct tag *c = cus__find_struct_by_name(kprobes_cus, &cu, name);
if (c != NULL) {
cus__emit_type_definitions(kprobes_cus, cu, c, fp_methods);
type__emit(c, cu, NULL, NULL, fp_methods);
}
}
/*
* Emit a forward declaration ("struct foo;" or "union bar").
*/
static void emit_class_fwd_decl(const char *name)
{
struct cu *cu;
struct tag *c = cus__find_struct_by_name(kprobes_cus, &cu, name);
if (c != NULL)
cus__emit_fwd_decl(kprobes_cus, tag__type(c), fp_methods);
}
/*
* Emit the definitions used in the resulting kernel module C source code,
* we do this to avoid using #includes, that would emit definitions for
* things we emit, causing redefinitions.
*/
static void emit_module_preamble(void)
{
fputs("#include \"ctracer_relay.h\"\n", fp_methods);
emit_struct_defs("jprobe");
emit_struct_defs("kretprobe");
emit_class_fwd_decl("pt_regs");
emit_class_fwd_decl("kretprobe_instance");
emit_function_defs("printk");
emit_function_defs("jprobe_return");
}
static const struct argp_option ctracer__options[] = {
{
.key = 'd',
.name = "src_dir",
.doc = "generate source files in this directory",
},
{
.key = 'D',
.name = "dir",
.doc = "load files in this directory",
},
{
.key = 'g',
.name = "glob",
.doc = "file mask to load",
},
{
.key = 'k',
.name = "kprobes",
.doc = "kprobes object file",
},
{
.key = 'r',
.name = "recursive",
.doc = "recursively load files",
},
{
.name = NULL,
}
};
static const char *dirname, *glob, *kprobes_filename;
static char *class_name;
static int recursive;
static error_t ctracer__options_parser(int key, char *arg,
struct argp_state *state __unused)
{
switch (key) {
case 'd': src_dir = arg; break;
case 'D': dirname = arg; break;
case 'g': glob = arg; break;
case 'k': kprobes_filename = 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;
const char *filename;
char functions_filename[PATH_MAX];
char methods_filename[PATH_MAX];
FILE *fp;
argp_parse(&ctracer__argp, argc, argv, 0, &remaining, NULL);
if (remaining < argc) {
switch (argc - remaining) {
case 1: if (kprobes_filename == NULL)
goto failure;
class_name = argv[remaining++]; break;
case 2: filename = argv[remaining++];
class_name = argv[remaining++]; break;
default: goto failure;
}
} else {
failure:
argp_help(&ctracer__argp, stderr, ARGP_HELP_SEE, "ctracer");
return EXIT_FAILURE;
}
/*
* Initialize libdwarves, for now just to get the machine L1 cacheline
* size, in the future may do more stuff.
*/
dwarves__init(0);
/*
* 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(&cus__definitions, &cus__fwd_decls);
if (methods_cus == NULL) {
out_enomem:
fputs("ctracer: insufficient memory\n", stderr);
return EXIT_FAILURE;
}
/*
* If --kprobes was specified load the binary with the definitions
* for the kprobes structs and functions used in the generated kernel
* module C source file.
*/
if (kprobes_filename != NULL) {
kprobes_cus = cus__new(&cus__definitions, &cus__fwd_decls);
if (kprobes_cus == NULL)
goto out_enomem;
err = cus__load(kprobes_cus, kprobes_filename);
if (err != 0) {
filename = kprobes_filename;
goto out_dwarf_err;
}
} else {
/*
* Or use the methods_cus specified for the methods as the
* source for the kprobes structs and functions definitions.
*/
kprobes_cus = methods_cus;
}
/*
* 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, dirname, glob,
recursive) != 0) {
fprintf(stderr, "ctracer: couldn't load DWARF info "
"from %s dir with glob %s\n",
dirname, glob);
return EXIT_FAILURE;
}
/*
* If a filename was specified, for instance "vmlinux", load it too.
*/
if (filename != NULL) {
err = cus__load(methods_cus, filename);
if (err != 0) {
out_dwarf_err:
cus__print_error_msg("ctracer", filename, err);
return EXIT_FAILURE;
}
}
/*
* See if the specified struct exists:
*/
class = cus__find_struct_by_name(methods_cus, &cu, class_name);
if (class == NULL) {
fprintf(stderr, "ctracer: struct %s not found!\n", class_name);
return EXIT_FAILURE;
}
snprintf(functions_filename, sizeof(functions_filename),
"%s/%s.functions", src_dir, class__name(tag__class(class)));
fp = fopen(functions_filename, "w");
if (fp == NULL) {
fprintf(stderr, "ctracer: couldn't create %s\n",
functions_filename);
exit(EXIT_FAILURE);
}
snprintf(methods_filename, sizeof(methods_filename),
"%s/ctracer_methods.c", src_dir);
fp_methods = fopen(methods_filename, "w");
if (fp_methods == NULL) {
fprintf(stderr, "ctracer: couldn't create %s\n",
methods_filename);
exit(EXIT_FAILURE);
}
emit_module_preamble();
cus__emit_type_definitions(methods_cus, cu, class, fp_methods);
type__emit(class, cu, NULL, NULL, fp_methods);
class__emit_subset(class, cu);
class__emit_ostra_converter(class, cu);
cus__for_each_cu(methods_cus, cu_find_methods_iterator,
class_name, NULL);
cus__for_each_cu(methods_cus, cu_emit_kprobes_iterator,
class_name, NULL);
cus__for_each_cu(methods_cus, cu_emit_kretprobes_iterator,
NULL, NULL);
fputs("struct jprobe *ctracer__jprobes[] = {", fp_methods);
cus__for_each_cu(methods_cus, cu_emit_kprobes_table_iterator,
fp, NULL);
/* Emit the sentinel */
fputs("\t(void *)0,\n};\n", fp_methods);
fclose(fp);
fputs("struct kretprobe *ctracer__kretprobes[] = {", fp_methods);
cus__for_each_cu(methods_cus, cu_emit_kretprobes_table_iterator,
NULL, NULL);
/* Emit the sentinel */
fputs("\t(void *)0,\n};\n", fp_methods);
return EXIT_SUCCESS;
}