/* * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com> * Copyright (C) 2015, Huawei Inc. */ #include <errno.h> #include <limits.h> #include <stdio.h> #include <stdlib.h> #include <linux/err.h> #include "debug.h" #include "llvm-utils.h" #include "config.h" #include "util.h" #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \ "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\ "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \ "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \ "-Wno-unused-value -Wno-pointer-sign " \ "-working-directory $WORKING_DIR " \ "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -" struct llvm_param llvm_param = { .clang_path = "clang", .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE, .clang_opt = NULL, .kbuild_dir = NULL, .kbuild_opts = NULL, .user_set_param = false, }; int perf_llvm_config(const char *var, const char *value) { if (prefixcmp(var, "llvm.")) return 0; var += sizeof("llvm.") - 1; if (!strcmp(var, "clang-path")) llvm_param.clang_path = strdup(value); else if (!strcmp(var, "clang-bpf-cmd-template")) llvm_param.clang_bpf_cmd_template = strdup(value); else if (!strcmp(var, "clang-opt")) llvm_param.clang_opt = strdup(value); else if (!strcmp(var, "kbuild-dir")) llvm_param.kbuild_dir = strdup(value); else if (!strcmp(var, "kbuild-opts")) llvm_param.kbuild_opts = strdup(value); else if (!strcmp(var, "dump-obj")) llvm_param.dump_obj = !!perf_config_bool(var, value); else return -1; llvm_param.user_set_param = true; return 0; } static int search_program(const char *def, const char *name, char *output) { char *env, *path, *tmp = NULL; char buf[PATH_MAX]; int ret; output[0] = '\0'; if (def && def[0] != '\0') { if (def[0] == '/') { if (access(def, F_OK) == 0) { strlcpy(output, def, PATH_MAX); return 0; } } else if (def[0] != '\0') name = def; } env = getenv("PATH"); if (!env) return -1; env = strdup(env); if (!env) return -1; ret = -ENOENT; path = strtok_r(env, ":", &tmp); while (path) { scnprintf(buf, sizeof(buf), "%s/%s", path, name); if (access(buf, F_OK) == 0) { strlcpy(output, buf, PATH_MAX); ret = 0; break; } path = strtok_r(NULL, ":", &tmp); } free(env); return ret; } #define READ_SIZE 4096 static int read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz) { int err = 0; void *buf = NULL; FILE *file = NULL; size_t read_sz = 0, buf_sz = 0; char serr[STRERR_BUFSIZE]; file = popen(cmd, "r"); if (!file) { pr_err("ERROR: unable to popen cmd: %s\n", str_error_r(errno, serr, sizeof(serr))); return -EINVAL; } while (!feof(file) && !ferror(file)) { /* * Make buf_sz always have obe byte extra space so we * can put '\0' there. */ if (buf_sz - read_sz < READ_SIZE + 1) { void *new_buf; buf_sz = read_sz + READ_SIZE + 1; new_buf = realloc(buf, buf_sz); if (!new_buf) { pr_err("ERROR: failed to realloc memory\n"); err = -ENOMEM; goto errout; } buf = new_buf; } read_sz += fread(buf + read_sz, 1, READ_SIZE, file); } if (buf_sz - read_sz < 1) { pr_err("ERROR: internal error\n"); err = -EINVAL; goto errout; } if (ferror(file)) { pr_err("ERROR: error occurred when reading from pipe: %s\n", str_error_r(errno, serr, sizeof(serr))); err = -EIO; goto errout; } err = WEXITSTATUS(pclose(file)); file = NULL; if (err) { err = -EINVAL; goto errout; } /* * If buf is string, give it terminal '\0' to make our life * easier. If buf is not string, that '\0' is out of space * indicated by read_sz so caller won't even notice it. */ ((char *)buf)[read_sz] = '\0'; if (!p_buf) free(buf); else *p_buf = buf; if (p_read_sz) *p_read_sz = read_sz; return 0; errout: if (file) pclose(file); free(buf); if (p_buf) *p_buf = NULL; if (p_read_sz) *p_read_sz = 0; return err; } static inline void force_set_env(const char *var, const char *value) { if (value) { setenv(var, value, 1); pr_debug("set env: %s=%s\n", var, value); } else { unsetenv(var); pr_debug("unset env: %s\n", var); } } static void version_notice(void) { pr_err( " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n" " \tYou may want to try git trunk:\n" " \t\tgit clone http://llvm.org/git/llvm.git\n" " \t\t and\n" " \t\tgit clone http://llvm.org/git/clang.git\n\n" " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n" " \tdebian/ubuntu:\n" " \t\thttp://llvm.org/apt\n\n" " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n" " \toption in [llvm] section of ~/.perfconfig to:\n\n" " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n" " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n" " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n" " \t(Replace /path/to/llc with path to your llc)\n\n" ); } static int detect_kbuild_dir(char **kbuild_dir) { const char *test_dir = llvm_param.kbuild_dir; const char *prefix_dir = ""; const char *suffix_dir = ""; char *autoconf_path; int err; if (!test_dir) { /* _UTSNAME_LENGTH is 65 */ char release[128]; err = fetch_kernel_version(NULL, release, sizeof(release)); if (err) return -EINVAL; test_dir = release; prefix_dir = "/lib/modules/"; suffix_dir = "/build"; } err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h", prefix_dir, test_dir, suffix_dir); if (err < 0) return -ENOMEM; if (access(autoconf_path, R_OK) == 0) { free(autoconf_path); err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir, suffix_dir); if (err < 0) return -ENOMEM; return 0; } free(autoconf_path); return -ENOENT; } static const char *kinc_fetch_script = "#!/usr/bin/env sh\n" "if ! test -d \"$KBUILD_DIR\"\n" "then\n" " exit -1\n" "fi\n" "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n" "then\n" " exit -1\n" "fi\n" "TMPDIR=`mktemp -d`\n" "if test -z \"$TMPDIR\"\n" "then\n" " exit -1\n" "fi\n" "cat << EOF > $TMPDIR/Makefile\n" "obj-y := dummy.o\n" "\\$(obj)/%.o: \\$(src)/%.c\n" "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n" "EOF\n" "touch $TMPDIR/dummy.c\n" "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n" "RET=$?\n" "rm -rf $TMPDIR\n" "exit $RET\n"; void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts) { static char *saved_kbuild_dir; static char *saved_kbuild_include_opts; int err; if (!kbuild_dir || !kbuild_include_opts) return; *kbuild_dir = NULL; *kbuild_include_opts = NULL; if (saved_kbuild_dir && saved_kbuild_include_opts && !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) { *kbuild_dir = strdup(saved_kbuild_dir); *kbuild_include_opts = strdup(saved_kbuild_include_opts); if (*kbuild_dir && *kbuild_include_opts) return; zfree(kbuild_dir); zfree(kbuild_include_opts); /* * Don't fall through: it may breaks saved_kbuild_dir and * saved_kbuild_include_opts if detect them again when * memory is low. */ return; } if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) { pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n"); pr_debug("Skip kbuild options detection.\n"); goto errout; } err = detect_kbuild_dir(kbuild_dir); if (err) { pr_warning( "WARNING:\tunable to get correct kernel building directory.\n" "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n" " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n" " \tdetection.\n\n"); goto errout; } pr_debug("Kernel build dir is set to %s\n", *kbuild_dir); force_set_env("KBUILD_DIR", *kbuild_dir); force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts); err = read_from_pipe(kinc_fetch_script, (void **)kbuild_include_opts, NULL); if (err) { pr_warning( "WARNING:\tunable to get kernel include directories from '%s'\n" "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n" " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n" " \toption in [llvm] to \"\" to suppress this detection.\n\n", *kbuild_dir); free(*kbuild_dir); *kbuild_dir = NULL; goto errout; } pr_debug("include option is set to %s\n", *kbuild_include_opts); saved_kbuild_dir = strdup(*kbuild_dir); saved_kbuild_include_opts = strdup(*kbuild_include_opts); if (!saved_kbuild_dir || !saved_kbuild_include_opts) { zfree(&saved_kbuild_dir); zfree(&saved_kbuild_include_opts); } return; errout: saved_kbuild_dir = ERR_PTR(-EINVAL); saved_kbuild_include_opts = ERR_PTR(-EINVAL); } int llvm__get_nr_cpus(void) { static int nr_cpus_avail = 0; char serr[STRERR_BUFSIZE]; if (nr_cpus_avail > 0) return nr_cpus_avail; nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF); if (nr_cpus_avail <= 0) { pr_err( "WARNING:\tunable to get available CPUs in this system: %s\n" " \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr))); nr_cpus_avail = 128; } return nr_cpus_avail; } void llvm__dump_obj(const char *path, void *obj_buf, size_t size) { char *obj_path = strdup(path); FILE *fp; char *p; if (!obj_path) { pr_warning("WARNING: Not enough memory, skip object dumping\n"); return; } p = strrchr(obj_path, '.'); if (!p || (strcmp(p, ".c") != 0)) { pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n", obj_path); goto out; } p[1] = 'o'; fp = fopen(obj_path, "wb"); if (!fp) { pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n", obj_path, strerror(errno)); goto out; } pr_info("LLVM: dumping %s\n", obj_path); if (fwrite(obj_buf, size, 1, fp) != 1) pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n", obj_path, strerror(errno)); fclose(fp); out: free(obj_path); } int llvm__compile_bpf(const char *path, void **p_obj_buf, size_t *p_obj_buf_sz) { size_t obj_buf_sz; void *obj_buf = NULL; int err, nr_cpus_avail; unsigned int kernel_version; char linux_version_code_str[64]; const char *clang_opt = llvm_param.clang_opt; char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64]; char serr[STRERR_BUFSIZE]; char *kbuild_dir = NULL, *kbuild_include_opts = NULL; const char *template = llvm_param.clang_bpf_cmd_template; if (path[0] != '-' && realpath(path, abspath) == NULL) { err = errno; pr_err("ERROR: problems with path %s: %s\n", path, str_error_r(err, serr, sizeof(serr))); return -err; } if (!template) template = CLANG_BPF_CMD_DEFAULT_TEMPLATE; err = search_program(llvm_param.clang_path, "clang", clang_path); if (err) { pr_err( "ERROR:\tunable to find clang.\n" "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n" " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n"); version_notice(); return -ENOENT; } /* * This is an optional work. Even it fail we can continue our * work. Needn't to check error return. */ llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts); nr_cpus_avail = llvm__get_nr_cpus(); snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d", nr_cpus_avail); if (fetch_kernel_version(&kernel_version, NULL, 0)) kernel_version = 0; snprintf(linux_version_code_str, sizeof(linux_version_code_str), "0x%x", kernel_version); force_set_env("NR_CPUS", nr_cpus_avail_str); force_set_env("LINUX_VERSION_CODE", linux_version_code_str); force_set_env("CLANG_EXEC", clang_path); force_set_env("CLANG_OPTIONS", clang_opt); force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts); force_set_env("WORKING_DIR", kbuild_dir ? : "."); /* * Since we may reset clang's working dir, path of source file * should be transferred into absolute path, except we want * stdin to be source file (testing). */ force_set_env("CLANG_SOURCE", (path[0] == '-') ? path : abspath); pr_debug("llvm compiling command template: %s\n", template); err = read_from_pipe(template, &obj_buf, &obj_buf_sz); if (err) { pr_err("ERROR:\tunable to compile %s\n", path); pr_err("Hint:\tCheck error message shown above.\n"); pr_err("Hint:\tYou can also pre-compile it into .o using:\n"); pr_err(" \t\tclang -target bpf -O2 -c %s\n", path); pr_err(" \twith proper -I and -D options.\n"); goto errout; } free(kbuild_dir); free(kbuild_include_opts); if (!p_obj_buf) free(obj_buf); else *p_obj_buf = obj_buf; if (p_obj_buf_sz) *p_obj_buf_sz = obj_buf_sz; return 0; errout: free(kbuild_dir); free(kbuild_include_opts); free(obj_buf); if (p_obj_buf) *p_obj_buf = NULL; if (p_obj_buf_sz) *p_obj_buf_sz = 0; return err; } int llvm__search_clang(void) { char clang_path[PATH_MAX]; return search_program(llvm_param.clang_path, "clang", clang_path); }