summaryrefslogtreecommitdiff
blob: b00e8187a6063e329049ab9a57023fe9113c598d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/*
 * Copyright 1999-2012 Gentoo Foundation
 * Distributed under the terms of the GNU General Public License v2
 * Author: Martin Schlemmer <azarah@gentoo.org>
 * az's lackey: Mike Frysinger <vapier@gentoo.org>
 */

#ifdef DEBUG
# define USE_DEBUG 1
#else
# define USE_DEBUG 0
#endif

#ifndef _FILE_OFFSET_BITS
# define _FILE_OFFSET_BITS 64	/* #471024 */
#endif

#include <errno.h>
#include <libgen.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>

#ifndef EPREFIX
# define EPREFIX ""
#endif

#define GCC_CONFIG EPREFIX "/usr/bin/gcc-config"
#define ENVD_BASE  EPREFIX "/etc/env.d/05gcc"

#define ARRAY_SIZE(arr) (sizeof(arr)/sizeof(arr[0]))

/* basename(3) is allowed to modify memory */
#undef basename
#define basename(path) \
({ \
	char *__path = path; \
	char *__ret = strrchr(__path, '/'); \
	__ret ? __ret + 1 : __path; \
})

struct wrapper_data {
	const char *name;
	char *fullname, *bin, *path;
};

static const struct {
	const char *alias;
	const char *target;
} wrapper_aliases[] = {
	{ "cc",  "gcc" },
	{ "f77", "gfortran" },
	{ "f95", "gfortran" },
};

#define wrapper_warn(fmt, ...) fprintf(stderr, "%s" fmt "\n", "gcc-config: ", ## __VA_ARGS__)
#define wrapper_err(fmt, ...) ({ wrapper_warn("%s" fmt, "error: ", ## __VA_ARGS__); exit(1); })
#define wrapper_errp(fmt, ...) wrapper_err(fmt ": %s", ## __VA_ARGS__, strerror(errno))
#define wrapper_dbg(fmt, ...) ({ if (USE_DEBUG) wrapper_warn(fmt, ## __VA_ARGS__); })

#define xmemwrap(func, proto, use) \
static void *x ## func proto \
{ \
	void *ret = func use; \
	if (!ret) \
		wrapper_err(#func "%s", ": out of memory"); \
	return ret; \
}
xmemwrap(malloc, (size_t size), (size))
xmemwrap(strdup, (const char *s), (s))

/* check_for_target checks in path for the file we are seeking
 * it returns 1 if found (with data->bin setup), 0 if not and
 * negative on error
 */
static int check_for_target(char *path, struct wrapper_data *data)
{
	struct stat sbuf;
	char str[PATH_MAX + 1];
	size_t path_len = strlen(path);
	size_t len = path_len + strlen(data->name) + 2;

	if (sizeof(str) < len)
		wrapper_warn("path too long: %s", path);

	strcpy(str, path);
	str[path_len] = '/';
	str[path_len+1] = '\0';
	strcat(str, data->name);

	/* Stat possible file to check that
	 * 1) it exist and is a regular file, and
	 * 2) it is not the wrapper itself, and
	 * 3) it is in a /gcc-bin/ directory tree
	 */
	if (strcmp(str, data->fullname) != 0 &&
	    strstr(str, "/gcc-bin/") != NULL &&
	    stat(str, &sbuf) == 0 &&
	    (S_ISREG(sbuf.st_mode) || S_ISLNK(sbuf.st_mode)))
	{
		wrapper_dbg("%s: found in %s", data->name, path);
		data->bin = xstrdup(str);
		return 1;
	}

	wrapper_dbg("%s: did not find in %s", data->name, path);
	return 0;
}

static int find_target_in_path(struct wrapper_data *data)
{
	char *token = NULL, *state = NULL;
	char *str;

	if (data->path == NULL)
		return 0;

	/* Make a copy since strtok_r will modify path */
	str = xstrdup(data->path);

	/* Find the first file with suitable name in PATH.  The idea here is
	 * that we do not want to bind ourselfs to something static like the
	 * default profile, or some odd environment variable, but want to be
	 * able to build something with a non default gcc by just tweaking
	 * the PATH ... */
	token = strtok_r(str, ":", &state);
	while (token != NULL) {
		if (check_for_target(token, data))
			return 1;
		token = strtok_r(NULL, ":", &state);
	}

	wrapper_dbg("%s: did not find in PATH", data->name);
	return 0;
}

/* find_target_in_envd parses /etc/env.d/05gcc, and tries to
 * extract PATH, which is set to the current profile's bin
 * directory ...
 */
static int find_target_in_envd(struct wrapper_data *data, int cross_compile)
{
	FILE *envfile = NULL;
	char *token = NULL, *state;
	char str[PATH_MAX + 1];
	char *strp = str;
	char envd_file[PATH_MAX + 1];

	if (!cross_compile) {
		/* for the sake of speed, we'll keep a symlink around for
		 * the native compiler.  #190260
		 */
		snprintf(envd_file, sizeof(envd_file)-1, EPREFIX "/etc/env.d/gcc/.NATIVE");
	} else {
		char *ctarget, *end = strrchr(data->name, '-');
		if (end == NULL)
			return 0;
		ctarget = xstrdup(data->name);
		ctarget[end - data->name] = '\0';
		snprintf(envd_file, PATH_MAX, "%s-%s", ENVD_BASE, ctarget);
		free(ctarget);
	}

	envfile = fopen(envd_file, "r");
	if (envfile == NULL)
		return 0;

	while (fgets(strp, PATH_MAX, envfile) != NULL) {
		/* Keep reading ENVD_FILE until we get a line that
		 * starts with 'GCC_PATH=' ... keep 'PATH=' around
		 * for older gcc versions.
		 */
		if (strncmp(strp, "GCC_PATH=", strlen("GCC_PATH=")) &&
		    strncmp(strp, "PATH=", strlen("PATH=")))
			continue;

		token = strtok_r(strp, "=", &state);
		if ((token != NULL) && token[0])
			/* The second token should be the value of PATH .. */
			token = strtok_r(NULL, "=", &state);
		else
			goto bail;

		if ((token != NULL) && token[0]) {
			strp = token;
			/* A bash variable may be unquoted, quoted with " or
			 * quoted with ', so extract the value without those ..
			 */
			token = strtok(strp, "\n\"\'");

			while (token != NULL) {
				if (check_for_target(token, data)) {
					fclose(envfile);
					return 1;
				}

				token = strtok(NULL, "\n\"\'");
			}
		}

		strp = str;
	}

 bail:
	fclose(envfile);
	return (cross_compile ? 0 : find_target_in_envd(data, 1));
}

static void find_wrapper_target(struct wrapper_data *data)
{
	if (find_target_in_path(data))
		return;

	if (find_target_in_envd(data, 0))
		return;

	/* Only our wrapper is in PATH, so get the CC path using
	 * gcc-config and execute the real binary in there ...
	 */
	FILE *inpipe = popen("ROOT= " GCC_CONFIG " --get-bin-path", "r");
	if (inpipe == NULL)
		wrapper_errp("could not open pipe");

	char str[PATH_MAX + 1];
	if (fgets(str, PATH_MAX, inpipe) == 0)
		wrapper_errp("could not get compiler binary path");

	/* chomp! */
	size_t plen = strlen(str);
	if (str[plen-1] == '\n')
		str[plen-1] = '\0';

	data->bin = xmalloc(plen + 1 + strlen(data->name) + 1);
	sprintf(data->bin, "%s/%s", str, data->name);

	pclose(inpipe);
}

/* This function modifies PATH to have gcc's bin path appended */
static void modify_path(struct wrapper_data *data)
{
	char *newpath = NULL, *token = NULL, *state;
	char dname_data[PATH_MAX + 1], str[PATH_MAX + 1];
	char *str2 = dname_data, *dname = dname_data;
	size_t len = 0;

	if (data->bin == NULL)
		return;

	if (data->path == NULL)
		return;

	snprintf(str2, PATH_MAX + 1, "%s", data->bin);

	if ((dname = dirname(str2)) == NULL)
		return;

	/* Make a copy since strtok_r will modify path */
	snprintf(str, PATH_MAX + 1, "%s", data->path);

	token = strtok_r(str, ":", &state);

	/* Check if we already appended our bin location to PATH */
	if ((token != NULL) && token[0])
		if (!strcmp(token, dname))
			return;

	len = strlen(dname) + strlen(data->path) + 2 + strlen("PATH") + 1;

	newpath = xmalloc(len);
	memset(newpath, 0, len);

	snprintf(newpath, len, "PATH=%s:%s", dname, data->path);
	putenv(newpath);
}

int main(int argc, char *argv[])
{
	struct wrapper_data data;

	memset(&data, 0, sizeof(data));

	if (getenv("PATH"))
		data.path = xstrdup(getenv("PATH"));

	/* What should we find ? */
	data.name = basename(argv[0]);

	/* Allow for common compiler names like cc->gcc */
	size_t i;
	for (i = 0; i < ARRAY_SIZE(wrapper_aliases); ++i)
		if (!strcmp(data.name, wrapper_aliases[i].alias))
			data.name = wrapper_aliases[i].target;

	/* What is the full name of our wrapper? */
	data.fullname = xmalloc(strlen(data.name) + sizeof(EPREFIX "/usr/bin/") + 1);
	sprintf(data.fullname, EPREFIX "/usr/bin/%s", data.name);

	find_wrapper_target(&data);

	modify_path(&data);

	free(data.path);
	data.path = NULL;

	/* Set argv[0] to the correct binary, else gcc can't find internal headers
	 * http://bugs.gentoo.org/8132
	 */
	argv[0] = data.bin;

	/* Ok, lets do it one more time ... */
	execv(data.bin, argv);

	/* shouldn't have made it here if things worked ... */
	wrapper_err("could not run/locate '%s'", data.name);

	return 123;
}