1 /*
2 * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
3 * Copyright (C) 2015, Huawei Inc.
4 */
5
6 #include <errno.h>
7 #include <limits.h>
8 #include <stdio.h>
9 #include <stdlib.h>
10 #include "debug.h"
11 #include "llvm-utils.h"
12 #include "config.h"
13 #include "util.h"
14
15 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
16 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
17 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
18 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \
19 "-Wno-unused-value -Wno-pointer-sign " \
20 "-working-directory $WORKING_DIR " \
21 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
22
23 struct llvm_param llvm_param = {
24 .clang_path = "clang",
25 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
26 .clang_opt = NULL,
27 .kbuild_dir = NULL,
28 .kbuild_opts = NULL,
29 .user_set_param = false,
30 };
31
perf_llvm_config(const char * var,const char * value)32 int perf_llvm_config(const char *var, const char *value)
33 {
34 if (prefixcmp(var, "llvm."))
35 return 0;
36 var += sizeof("llvm.") - 1;
37
38 if (!strcmp(var, "clang-path"))
39 llvm_param.clang_path = strdup(value);
40 else if (!strcmp(var, "clang-bpf-cmd-template"))
41 llvm_param.clang_bpf_cmd_template = strdup(value);
42 else if (!strcmp(var, "clang-opt"))
43 llvm_param.clang_opt = strdup(value);
44 else if (!strcmp(var, "kbuild-dir"))
45 llvm_param.kbuild_dir = strdup(value);
46 else if (!strcmp(var, "kbuild-opts"))
47 llvm_param.kbuild_opts = strdup(value);
48 else if (!strcmp(var, "dump-obj"))
49 llvm_param.dump_obj = !!perf_config_bool(var, value);
50 else
51 return -1;
52 llvm_param.user_set_param = true;
53 return 0;
54 }
55
56 static int
search_program(const char * def,const char * name,char * output)57 search_program(const char *def, const char *name,
58 char *output)
59 {
60 char *env, *path, *tmp = NULL;
61 char buf[PATH_MAX];
62 int ret;
63
64 output[0] = '\0';
65 if (def && def[0] != '\0') {
66 if (def[0] == '/') {
67 if (access(def, F_OK) == 0) {
68 strlcpy(output, def, PATH_MAX);
69 return 0;
70 }
71 } else if (def[0] != '\0')
72 name = def;
73 }
74
75 env = getenv("PATH");
76 if (!env)
77 return -1;
78 env = strdup(env);
79 if (!env)
80 return -1;
81
82 ret = -ENOENT;
83 path = strtok_r(env, ":", &tmp);
84 while (path) {
85 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
86 if (access(buf, F_OK) == 0) {
87 strlcpy(output, buf, PATH_MAX);
88 ret = 0;
89 break;
90 }
91 path = strtok_r(NULL, ":", &tmp);
92 }
93
94 free(env);
95 return ret;
96 }
97
98 #define READ_SIZE 4096
99 static int
read_from_pipe(const char * cmd,void ** p_buf,size_t * p_read_sz)100 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
101 {
102 int err = 0;
103 void *buf = NULL;
104 FILE *file = NULL;
105 size_t read_sz = 0, buf_sz = 0;
106 char serr[STRERR_BUFSIZE];
107
108 file = popen(cmd, "r");
109 if (!file) {
110 pr_err("ERROR: unable to popen cmd: %s\n",
111 str_error_r(errno, serr, sizeof(serr)));
112 return -EINVAL;
113 }
114
115 while (!feof(file) && !ferror(file)) {
116 /*
117 * Make buf_sz always have obe byte extra space so we
118 * can put '\0' there.
119 */
120 if (buf_sz - read_sz < READ_SIZE + 1) {
121 void *new_buf;
122
123 buf_sz = read_sz + READ_SIZE + 1;
124 new_buf = realloc(buf, buf_sz);
125
126 if (!new_buf) {
127 pr_err("ERROR: failed to realloc memory\n");
128 err = -ENOMEM;
129 goto errout;
130 }
131
132 buf = new_buf;
133 }
134 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
135 }
136
137 if (buf_sz - read_sz < 1) {
138 pr_err("ERROR: internal error\n");
139 err = -EINVAL;
140 goto errout;
141 }
142
143 if (ferror(file)) {
144 pr_err("ERROR: error occurred when reading from pipe: %s\n",
145 str_error_r(errno, serr, sizeof(serr)));
146 err = -EIO;
147 goto errout;
148 }
149
150 err = WEXITSTATUS(pclose(file));
151 file = NULL;
152 if (err) {
153 err = -EINVAL;
154 goto errout;
155 }
156
157 /*
158 * If buf is string, give it terminal '\0' to make our life
159 * easier. If buf is not string, that '\0' is out of space
160 * indicated by read_sz so caller won't even notice it.
161 */
162 ((char *)buf)[read_sz] = '\0';
163
164 if (!p_buf)
165 free(buf);
166 else
167 *p_buf = buf;
168
169 if (p_read_sz)
170 *p_read_sz = read_sz;
171 return 0;
172
173 errout:
174 if (file)
175 pclose(file);
176 free(buf);
177 if (p_buf)
178 *p_buf = NULL;
179 if (p_read_sz)
180 *p_read_sz = 0;
181 return err;
182 }
183
184 static inline void
force_set_env(const char * var,const char * value)185 force_set_env(const char *var, const char *value)
186 {
187 if (value) {
188 setenv(var, value, 1);
189 pr_debug("set env: %s=%s\n", var, value);
190 } else {
191 unsetenv(var);
192 pr_debug("unset env: %s\n", var);
193 }
194 }
195
196 static void
version_notice(void)197 version_notice(void)
198 {
199 pr_err(
200 " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
201 " \tYou may want to try git trunk:\n"
202 " \t\tgit clone http://llvm.org/git/llvm.git\n"
203 " \t\t and\n"
204 " \t\tgit clone http://llvm.org/git/clang.git\n\n"
205 " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
206 " \tdebian/ubuntu:\n"
207 " \t\thttp://llvm.org/apt\n\n"
208 " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
209 " \toption in [llvm] section of ~/.perfconfig to:\n\n"
210 " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
211 " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
212 " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
213 " \t(Replace /path/to/llc with path to your llc)\n\n"
214 );
215 }
216
detect_kbuild_dir(char ** kbuild_dir)217 static int detect_kbuild_dir(char **kbuild_dir)
218 {
219 const char *test_dir = llvm_param.kbuild_dir;
220 const char *prefix_dir = "";
221 const char *suffix_dir = "";
222
223 char *autoconf_path;
224
225 int err;
226
227 if (!test_dir) {
228 /* _UTSNAME_LENGTH is 65 */
229 char release[128];
230
231 err = fetch_kernel_version(NULL, release,
232 sizeof(release));
233 if (err)
234 return -EINVAL;
235
236 test_dir = release;
237 prefix_dir = "/lib/modules/";
238 suffix_dir = "/build";
239 }
240
241 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
242 prefix_dir, test_dir, suffix_dir);
243 if (err < 0)
244 return -ENOMEM;
245
246 if (access(autoconf_path, R_OK) == 0) {
247 free(autoconf_path);
248
249 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
250 suffix_dir);
251 if (err < 0)
252 return -ENOMEM;
253 return 0;
254 }
255 free(autoconf_path);
256 return -ENOENT;
257 }
258
259 static const char *kinc_fetch_script =
260 "#!/usr/bin/env sh\n"
261 "if ! test -d \"$KBUILD_DIR\"\n"
262 "then\n"
263 " exit -1\n"
264 "fi\n"
265 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
266 "then\n"
267 " exit -1\n"
268 "fi\n"
269 "TMPDIR=`mktemp -d`\n"
270 "if test -z \"$TMPDIR\"\n"
271 "then\n"
272 " exit -1\n"
273 "fi\n"
274 "cat << EOF > $TMPDIR/Makefile\n"
275 "obj-y := dummy.o\n"
276 "\\$(obj)/%.o: \\$(src)/%.c\n"
277 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
278 "EOF\n"
279 "touch $TMPDIR/dummy.c\n"
280 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
281 "RET=$?\n"
282 "rm -rf $TMPDIR\n"
283 "exit $RET\n";
284
285 static inline void
get_kbuild_opts(char ** kbuild_dir,char ** kbuild_include_opts)286 get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
287 {
288 int err;
289
290 if (!kbuild_dir || !kbuild_include_opts)
291 return;
292
293 *kbuild_dir = NULL;
294 *kbuild_include_opts = NULL;
295
296 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
297 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
298 pr_debug("Skip kbuild options detection.\n");
299 return;
300 }
301
302 err = detect_kbuild_dir(kbuild_dir);
303 if (err) {
304 pr_warning(
305 "WARNING:\tunable to get correct kernel building directory.\n"
306 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
307 " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
308 " \tdetection.\n\n");
309 return;
310 }
311
312 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
313 force_set_env("KBUILD_DIR", *kbuild_dir);
314 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
315 err = read_from_pipe(kinc_fetch_script,
316 (void **)kbuild_include_opts,
317 NULL);
318 if (err) {
319 pr_warning(
320 "WARNING:\tunable to get kernel include directories from '%s'\n"
321 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
322 " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
323 " \toption in [llvm] to \"\" to suppress this detection.\n\n",
324 *kbuild_dir);
325
326 free(*kbuild_dir);
327 *kbuild_dir = NULL;
328 return;
329 }
330
331 pr_debug("include option is set to %s\n", *kbuild_include_opts);
332 }
333
334 static void
dump_obj(const char * path,void * obj_buf,size_t size)335 dump_obj(const char *path, void *obj_buf, size_t size)
336 {
337 char *obj_path = strdup(path);
338 FILE *fp;
339 char *p;
340
341 if (!obj_path) {
342 pr_warning("WARNING: No enough memory, skip object dumping\n");
343 return;
344 }
345
346 p = strrchr(obj_path, '.');
347 if (!p || (strcmp(p, ".c") != 0)) {
348 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
349 obj_path);
350 goto out;
351 }
352
353 p[1] = 'o';
354 fp = fopen(obj_path, "wb");
355 if (!fp) {
356 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
357 obj_path, strerror(errno));
358 goto out;
359 }
360
361 pr_info("LLVM: dumping %s\n", obj_path);
362 if (fwrite(obj_buf, size, 1, fp) != 1)
363 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
364 obj_path, strerror(errno));
365 fclose(fp);
366 out:
367 free(obj_path);
368 }
369
llvm__compile_bpf(const char * path,void ** p_obj_buf,size_t * p_obj_buf_sz)370 int llvm__compile_bpf(const char *path, void **p_obj_buf,
371 size_t *p_obj_buf_sz)
372 {
373 size_t obj_buf_sz;
374 void *obj_buf = NULL;
375 int err, nr_cpus_avail;
376 unsigned int kernel_version;
377 char linux_version_code_str[64];
378 const char *clang_opt = llvm_param.clang_opt;
379 char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
380 char serr[STRERR_BUFSIZE];
381 char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
382 const char *template = llvm_param.clang_bpf_cmd_template;
383
384 if (path[0] != '-' && realpath(path, abspath) == NULL) {
385 err = errno;
386 pr_err("ERROR: problems with path %s: %s\n",
387 path, str_error_r(err, serr, sizeof(serr)));
388 return -err;
389 }
390
391 if (!template)
392 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
393
394 err = search_program(llvm_param.clang_path,
395 "clang", clang_path);
396 if (err) {
397 pr_err(
398 "ERROR:\tunable to find clang.\n"
399 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
400 " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
401 version_notice();
402 return -ENOENT;
403 }
404
405 /*
406 * This is an optional work. Even it fail we can continue our
407 * work. Needn't to check error return.
408 */
409 get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
410
411 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
412 if (nr_cpus_avail <= 0) {
413 pr_err(
414 "WARNING:\tunable to get available CPUs in this system: %s\n"
415 " \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
416 nr_cpus_avail = 128;
417 }
418 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
419 nr_cpus_avail);
420
421 if (fetch_kernel_version(&kernel_version, NULL, 0))
422 kernel_version = 0;
423
424 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
425 "0x%x", kernel_version);
426
427 force_set_env("NR_CPUS", nr_cpus_avail_str);
428 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
429 force_set_env("CLANG_EXEC", clang_path);
430 force_set_env("CLANG_OPTIONS", clang_opt);
431 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
432 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
433
434 /*
435 * Since we may reset clang's working dir, path of source file
436 * should be transferred into absolute path, except we want
437 * stdin to be source file (testing).
438 */
439 force_set_env("CLANG_SOURCE",
440 (path[0] == '-') ? path : abspath);
441
442 pr_debug("llvm compiling command template: %s\n", template);
443 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
444 if (err) {
445 pr_err("ERROR:\tunable to compile %s\n", path);
446 pr_err("Hint:\tCheck error message shown above.\n");
447 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
448 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
449 pr_err(" \twith proper -I and -D options.\n");
450 goto errout;
451 }
452
453 free(kbuild_dir);
454 free(kbuild_include_opts);
455
456 if (llvm_param.dump_obj)
457 dump_obj(path, obj_buf, obj_buf_sz);
458
459 if (!p_obj_buf)
460 free(obj_buf);
461 else
462 *p_obj_buf = obj_buf;
463
464 if (p_obj_buf_sz)
465 *p_obj_buf_sz = obj_buf_sz;
466 return 0;
467 errout:
468 free(kbuild_dir);
469 free(kbuild_include_opts);
470 free(obj_buf);
471 if (p_obj_buf)
472 *p_obj_buf = NULL;
473 if (p_obj_buf_sz)
474 *p_obj_buf_sz = 0;
475 return err;
476 }
477
llvm__search_clang(void)478 int llvm__search_clang(void)
479 {
480 char clang_path[PATH_MAX];
481
482 return search_program(llvm_param.clang_path, "clang", clang_path);
483 }
484