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