xref: /openbmc/u-boot/env/common.c (revision 748ad078)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2000-2010
4  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5  *
6  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
7  * Andreas Heppel <aheppel@sysgo.de>
8  */
9 
10 #include <common.h>
11 #include <command.h>
12 #include <environment.h>
13 #include <linux/stddef.h>
14 #include <search.h>
15 #include <errno.h>
16 #include <malloc.h>
17 
18 DECLARE_GLOBAL_DATA_PTR;
19 
20 /************************************************************************
21  * Default settings to be used when no valid environment is found
22  */
23 #include <env_default.h>
24 
25 struct hsearch_data env_htab = {
26 	.change_ok = env_flags_validate,
27 };
28 
29 /*
30  * Read an environment variable as a boolean
31  * Return -1 if variable does not exist (default to true)
32  */
env_get_yesno(const char * var)33 int env_get_yesno(const char *var)
34 {
35 	char *s = env_get(var);
36 
37 	if (s == NULL)
38 		return -1;
39 	return (*s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T') ?
40 		1 : 0;
41 }
42 
43 /*
44  * Look up the variable from the default environment
45  */
env_get_default(const char * name)46 char *env_get_default(const char *name)
47 {
48 	char *ret_val;
49 	unsigned long really_valid = gd->env_valid;
50 	unsigned long real_gd_flags = gd->flags;
51 
52 	/* Pretend that the image is bad. */
53 	gd->flags &= ~GD_FLG_ENV_READY;
54 	gd->env_valid = ENV_INVALID;
55 	ret_val = env_get(name);
56 	gd->env_valid = really_valid;
57 	gd->flags = real_gd_flags;
58 	return ret_val;
59 }
60 
set_default_env(const char * s,int flags)61 void set_default_env(const char *s, int flags)
62 {
63 	if (sizeof(default_environment) > ENV_SIZE) {
64 		puts("*** Error - default environment is too large\n\n");
65 		return;
66 	}
67 
68 	if (s) {
69 		if ((flags & H_INTERACTIVE) == 0) {
70 			printf("*** Warning - %s, "
71 				"using default environment\n\n", s);
72 		} else {
73 			puts(s);
74 		}
75 	} else {
76 		debug("Using default environment\n");
77 	}
78 
79 	if (himport_r(&env_htab, (char *)default_environment,
80 			sizeof(default_environment), '\0', flags, 0,
81 			0, NULL) == 0)
82 		pr_err("## Error: Environment import failed: errno = %d\n",
83 		       errno);
84 
85 	gd->flags |= GD_FLG_ENV_READY;
86 	gd->flags |= GD_FLG_ENV_DEFAULT;
87 }
88 
89 
90 /* [re]set individual variables to their value in the default environment */
set_default_vars(int nvars,char * const vars[],int flags)91 int set_default_vars(int nvars, char * const vars[], int flags)
92 {
93 	/*
94 	 * Special use-case: import from default environment
95 	 * (and use \0 as a separator)
96 	 */
97 	flags |= H_NOCLEAR;
98 	return himport_r(&env_htab, (const char *)default_environment,
99 				sizeof(default_environment), '\0',
100 				flags, 0, nvars, vars);
101 }
102 
103 /*
104  * Check if CRC is valid and (if yes) import the environment.
105  * Note that "buf" may or may not be aligned.
106  */
env_import(const char * buf,int check)107 int env_import(const char *buf, int check)
108 {
109 	env_t *ep = (env_t *)buf;
110 
111 	if (check) {
112 		uint32_t crc;
113 
114 		memcpy(&crc, &ep->crc, sizeof(crc));
115 
116 		if (crc32(0, ep->data, ENV_SIZE) != crc) {
117 			set_default_env("bad CRC", 0);
118 			return -ENOMSG; /* needed for env_load() */
119 		}
120 	}
121 
122 	if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
123 			0, NULL)) {
124 		gd->flags |= GD_FLG_ENV_READY;
125 		return 0;
126 	}
127 
128 	pr_err("Cannot import environment: errno = %d\n", errno);
129 
130 	set_default_env("import failed", 0);
131 
132 	return -EIO;
133 }
134 
135 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
136 static unsigned char env_flags;
137 
env_import_redund(const char * buf1,int buf1_read_fail,const char * buf2,int buf2_read_fail)138 int env_import_redund(const char *buf1, int buf1_read_fail,
139 		      const char *buf2, int buf2_read_fail)
140 {
141 	int crc1_ok, crc2_ok;
142 	env_t *ep, *tmp_env1, *tmp_env2;
143 
144 	tmp_env1 = (env_t *)buf1;
145 	tmp_env2 = (env_t *)buf2;
146 
147 	if (buf1_read_fail && buf2_read_fail) {
148 		puts("*** Error - No Valid Environment Area found\n");
149 	} else if (buf1_read_fail || buf2_read_fail) {
150 		puts("*** Warning - some problems detected ");
151 		puts("reading environment; recovered successfully\n");
152 	}
153 
154 	if (buf1_read_fail && buf2_read_fail) {
155 		set_default_env("bad env area", 0);
156 		return -EIO;
157 	} else if (!buf1_read_fail && buf2_read_fail) {
158 		gd->env_valid = ENV_VALID;
159 		return env_import((char *)tmp_env1, 1);
160 	} else if (buf1_read_fail && !buf2_read_fail) {
161 		gd->env_valid = ENV_REDUND;
162 		return env_import((char *)tmp_env2, 1);
163 	}
164 
165 	crc1_ok = crc32(0, tmp_env1->data, ENV_SIZE) ==
166 			tmp_env1->crc;
167 	crc2_ok = crc32(0, tmp_env2->data, ENV_SIZE) ==
168 			tmp_env2->crc;
169 
170 	if (!crc1_ok && !crc2_ok) {
171 		set_default_env("bad CRC", 0);
172 		return -ENOMSG; /* needed for env_load() */
173 	} else if (crc1_ok && !crc2_ok) {
174 		gd->env_valid = ENV_VALID;
175 	} else if (!crc1_ok && crc2_ok) {
176 		gd->env_valid = ENV_REDUND;
177 	} else {
178 		/* both ok - check serial */
179 		if (tmp_env1->flags == 255 && tmp_env2->flags == 0)
180 			gd->env_valid = ENV_REDUND;
181 		else if (tmp_env2->flags == 255 && tmp_env1->flags == 0)
182 			gd->env_valid = ENV_VALID;
183 		else if (tmp_env1->flags > tmp_env2->flags)
184 			gd->env_valid = ENV_VALID;
185 		else if (tmp_env2->flags > tmp_env1->flags)
186 			gd->env_valid = ENV_REDUND;
187 		else /* flags are equal - almost impossible */
188 			gd->env_valid = ENV_VALID;
189 	}
190 
191 	if (gd->env_valid == ENV_VALID)
192 		ep = tmp_env1;
193 	else
194 		ep = tmp_env2;
195 
196 	env_flags = ep->flags;
197 	return env_import((char *)ep, 0);
198 }
199 #endif /* CONFIG_SYS_REDUNDAND_ENVIRONMENT */
200 
201 /* Export the environment and generate CRC for it. */
env_export(env_t * env_out)202 int env_export(env_t *env_out)
203 {
204 	char *res;
205 	ssize_t	len;
206 
207 	res = (char *)env_out->data;
208 	len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
209 	if (len < 0) {
210 		pr_err("Cannot export environment: errno = %d\n", errno);
211 		return 1;
212 	}
213 
214 	env_out->crc = crc32(0, env_out->data, ENV_SIZE);
215 
216 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
217 	env_out->flags = ++env_flags; /* increase the serial */
218 #endif
219 
220 	return 0;
221 }
222 
env_relocate(void)223 void env_relocate(void)
224 {
225 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
226 	env_reloc();
227 	env_fix_drivers();
228 	env_htab.change_ok += gd->reloc_off;
229 #endif
230 	if (gd->env_valid == ENV_INVALID) {
231 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
232 		/* Environment not changable */
233 		set_default_env(NULL, 0);
234 #else
235 		bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
236 		set_default_env("bad CRC", 0);
237 #endif
238 	} else {
239 		env_load();
240 	}
241 }
242 
243 #ifdef CONFIG_AUTO_COMPLETE
env_complete(char * var,int maxv,char * cmdv[],int bufsz,char * buf,bool dollar_comp)244 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf,
245 		 bool dollar_comp)
246 {
247 	ENTRY *match;
248 	int found, idx;
249 
250 	if (dollar_comp) {
251 		/*
252 		 * When doing $ completion, the first character should
253 		 * obviously be a '$'.
254 		 */
255 		if (var[0] != '$')
256 			return 0;
257 
258 		var++;
259 
260 		/*
261 		 * The second one, if present, should be a '{', as some
262 		 * configuration of the u-boot shell expand ${var} but not
263 		 * $var.
264 		 */
265 		if (var[0] == '{')
266 			var++;
267 		else if (var[0] != '\0')
268 			return 0;
269 	}
270 
271 	idx = 0;
272 	found = 0;
273 	cmdv[0] = NULL;
274 
275 
276 	while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
277 		int vallen = strlen(match->key) + 1;
278 
279 		if (found >= maxv - 2 ||
280 		    bufsz < vallen + (dollar_comp ? 3 : 0))
281 			break;
282 
283 		cmdv[found++] = buf;
284 
285 		/* Add the '${' prefix to each var when doing $ completion. */
286 		if (dollar_comp) {
287 			strcpy(buf, "${");
288 			buf += 2;
289 			bufsz -= 3;
290 		}
291 
292 		memcpy(buf, match->key, vallen);
293 		buf += vallen;
294 		bufsz -= vallen;
295 
296 		if (dollar_comp) {
297 			/*
298 			 * This one is a bit odd: vallen already contains the
299 			 * '\0' character but we need to add the '}' suffix,
300 			 * hence the buf - 1 here. strcpy() will add the '\0'
301 			 * character just after '}'. buf is then incremented
302 			 * to account for the extra '}' we just added.
303 			 */
304 			strcpy(buf - 1, "}");
305 			buf++;
306 		}
307 	}
308 
309 	qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
310 
311 	if (idx)
312 		cmdv[found++] = dollar_comp ? "${...}" : "...";
313 
314 	cmdv[found] = NULL;
315 	return found;
316 }
317 #endif
318