path: root/tools/perf/util/dso.c

// SPDX-License-Identifier: GPL-2.0
#include <asm/bug.h>
#include <linux/kernel.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include "compress.h"
#include "namespaces.h"
#include "path.h"
#include "map.h"
#include "symbol.h"
#include "srcline.h"
#include "dso.h"
#include "machine.h"
#include "auxtrace.h"
#include "util.h"
#include "debug.h"
#include "string2.h"
#include "vdso.h"

static const char * const debuglink_paths[] = {
	"%.0s%s",
	"%s/%s",
	"%s/.debug/%s",
	"/usr/lib/debug%s/%s"
};

char dso__symtab_origin(const struct dso *dso)
{
	static const char origin[] = {
		[DSO_BINARY_TYPE__KALLSYMS]			= 'k',
		[DSO_BINARY_TYPE__VMLINUX]			= 'v',
		[DSO_BINARY_TYPE__JAVA_JIT]			= 'j',
		[DSO_BINARY_TYPE__DEBUGLINK]			= 'l',
		[DSO_BINARY_TYPE__BUILD_ID_CACHE]		= 'B',
		[DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO]	= 'D',
		[DSO_BINARY_TYPE__FEDORA_DEBUGINFO]		= 'f',
		[DSO_BINARY_TYPE__UBUNTU_DEBUGINFO]		= 'u',
		[DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO]	= 'o',
		[DSO_BINARY_TYPE__BUILDID_DEBUGINFO]		= 'b',
		[DSO_BINARY_TYPE__SYSTEM_PATH_DSO]		= 'd',
		[DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE]		= 'K',
		[DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP]	= 'm',
		[DSO_BINARY_TYPE__GUEST_KALLSYMS]		= 'g',
		[DSO_BINARY_TYPE__GUEST_KMODULE]		= 'G',
		[DSO_BINARY_TYPE__GUEST_KMODULE_COMP]		= 'M',
		[DSO_BINARY_TYPE__GUEST_VMLINUX]		= 'V',
	};

	if (dso == NULL || dso->symtab_type == DSO_BINARY_TYPE__NOT_FOUND)
		return '!';
	return origin[dso->symtab_type];
}

int dso__read_binary_type_filename(const struct dso *dso,
				   enum dso_binary_type type,
				   char *root_dir, char *filename, size_t size)
{
	char build_id_hex[SBUILD_ID_SIZE];
	int ret = 0;
	size_t len;

	switch (type) {
	case DSO_BINARY_TYPE__DEBUGLINK:
	{
		const char *last_slash;
		char dso_dir[PATH_MAX];
		char symfile[PATH_MAX];
		unsigned int i;

		len = __symbol__join_symfs(filename, size, dso->long_name);
		last_slash = filename + len;
		while (last_slash != filename && *last_slash != '/')
			last_slash--;

		strncpy(dso_dir, filename, last_slash - filename);
		dso_dir[last_slash-filename] = '\0';

		if (!is_regular_file(filename)) {
			ret = -1;
			break;
		}

		ret = filename__read_debuglink(filename, symfile, PATH_MAX);
		if (ret)
			break;

		/* Check predefined locations where debug file might reside */
		ret = -1;
		for (i = 0; i < ARRAY_SIZE(debuglink_paths); i++) {
			snprintf(filename, size,
					debuglink_paths[i], dso_dir, symfile);
			if (is_regular_file(filename)) {
				ret = 0;
				break;
			}
		}

		break;
	}
	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
		if (dso__build_id_filename(dso, filename, size, false) == NULL)
			ret = -1;
		break;

	case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
		if (dso__build_id_filename(dso, filename, size, true) == NULL)
			ret = -1;
		break;

	case DSO_BINARY_TYPE__FEDORA_DEBUGINFO:
		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
		snprintf(filename + len, size - len, "%s.debug", dso->long_name);
		break;

	case DSO_BINARY_TYPE__UBUNTU_DEBUGINFO:
		len = __symbol__join_symfs(filename, size, "/usr/lib/debug");
		snprintf(filename + len, size - len, "%s", dso->long_name);
		break;

	case DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO:
	{
		const char *last_slash;
		size_t dir_size;

		last_slash = dso->long_name + dso->long_name_len;
		while (last_slash != dso->long_name && *last_slash != '/')
			last_slash--;

		len = __symbol__join_symfs(filename, size, "");
		dir_size = last_slash - dso->long_name + 2;
		if (dir_size > (size - len)) {
			ret = -1;
			break;
		}
		len += scnprintf(filename + len, dir_size, "%s",  dso->long_name);
		len += scnprintf(filename + len , size - len, ".debug%s",
								last_slash);
		break;
	}

	case DSO_BINARY_TYPE__BUILDID_DEBUGINFO:
		if (!dso->has_build_id) {
			ret = -1;
			break;
		}

		build_id__sprintf(dso->build_id,
				  sizeof(dso->build_id),
				  build_id_hex);
		len = __symbol__join_symfs(filename, size, "/usr/lib/debug/.build-id/");
		snprintf(filename + len, size - len, "%.2s/%s.debug",
			 build_id_hex, build_id_hex + 2);
		break;

	case DSO_BINARY_TYPE__VMLINUX:
	case DSO_BINARY_TYPE__GUEST_VMLINUX:
	case DSO_BINARY_TYPE__SYSTEM_PATH_DSO:
		__symbol__join_symfs(filename, size, dso->long_name);
		break;

	case DSO_BINARY_TYPE__GUEST_KMODULE:
	case DSO_BINARY_TYPE__GUEST_KMODULE_COMP:
		path__join3(filename, size, symbol_conf.symfs,
			    root_dir, dso->long_name);
		break;

	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE:
	case DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP:
		__symbol__join_symfs(filename, size, dso->long_name);
		break;

	case DSO_BINARY_TYPE__KCORE:
	case DSO_BINARY_TYPE__GUEST_KCORE:
		snprintf(filename, size, "%s", dso->long_name);
		break;

	default:
	case DSO_BINARY_TYPE__KALLSYMS:
	case DSO_BINARY_TYPE__GUEST_KALLSYMS:
	case DSO_BINARY_TYPE__JAVA_JIT:
	case DSO_BINARY_TYPE__BPF_PROG_INFO:
	case DSO_BINARY_TYPE__NOT_FOUND:
		ret = -1;
		break;
	}

	return ret;
}

enum {
	COMP_ID__NONE = 0,
};

static const struct {
	const char *fmt;
	int (*decompress)(const char *input, int output);
	bool (*is_compressed)(const char *input);
} compressions[] = {
	[COMP_ID__NONE] = { .fmt = NULL, },
#ifdef HAVE_ZLIB_SUPPORT
	{ "gz", gzip_decompress_to_file, gzip_is_compressed },
#endif
#ifdef HAVE_LZMA_SUPPORT
	{ "xz", lzma_decompress_to_file, lzma_is_compressed },
#endif
	{ NULL, NULL, NULL },
};

static int is_supported_compression(const char *ext)
{
	unsigned i;

	for (i = 1; compressions[i].fmt; i++) {
		if (!strcmp(ext, compressions[i].fmt))
			return i;
	}
	return COMP_ID__NONE;
}

bool is_kernel_module(const char *pathname, int cpumode)
{
	struct kmod_path m;
	int mode = cpumode & PERF_RECORD_MISC_CPUMODE_MASK;

	WARN_ONCE(mode != cpumode,
		  "Internal error: passing unmasked cpumode (%x) to is_kernel_module",
		  cpumode);

	switch (mode) {
	case PERF_RECORD_MISC_USER:
	case PERF_RECORD_MISC_HYPERVISOR:
	case PERF_RECORD_MISC_GUEST_USER:
		return false;
	/* Treat PERF_RECORD_MISC_CPUMODE_UNKNOWN as kernel */
	default:
		if (kmod_path__parse(&m, pathname)) {
			pr_err("Failed to check whether %s is a kernel module or not. Assume it is.",
					pathname);
			return true;
		}
	}

	return m.kmod;
}

bool dso__needs_decompress(struct dso *dso)
{
	return dso->symtab_type == DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP ||
		dso->symtab_type == DSO_BINARY_TYPE__GUEST_KMODULE_COMP;
}

static int decompress_kmodule(struct dso *dso, const char *name,
			      char *pathname, size_t len)
{
	char tmpbuf[] = KMOD_DECOMP_NAME;
	int fd = -1;

	if (!dso__needs_decompress(dso))
		return -1;

	if (dso->comp == COMP_ID__NONE)
		return -1;

	/*
	 * We have proper compression id for DSO and yet the file
	 * behind the 'name' can still be plain uncompressed object.
	 *
	 * The reason is behind the logic we open the DSO object files,
	 * when we try all possible 'debug' objects until we find the
	 * data. So even if the DSO is represented by 'krava.xz' module,
	 * we can end up here opening ~/.debug/....23432432/debug' file
	 * which is not compressed.
	 *
	 * To keep this transparent, we detect this and return the file
	 * descriptor to the uncompressed file.
	 */
	if (!compressions[dso->comp].is_compre