env/common.c

   1 /*
   2  * (C) Copyright 2000-2010
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * (C) Copyright 2001 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   6  * Andreas Heppel <aheppel@sysgo.de>
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12 #include <command.h>
  13 #include <environment.h>
  14 #include <linux/stddef.h>
  15 #include <search.h>
  16 #include <errno.h>
  17 #include <malloc.h>
  18
  19 DECLARE_GLOBAL_DATA_PTR;
  20
  21 /************************************************************************
  22  * Default settings to be used when no valid environment is found
  23  */
  24 #include <env_default.h>
  25
  26 struct hsearch_data env_htab = {
  27         .change_ok = env_flags_validate,
  28 };
  29
  30 /*
  31  * Read an environment variable as a boolean
  32  * Return -1 if variable does not exist (default to true)
  33  */
  34 int env_get_yesno(const char *var)
  35 {
  36         char *s = env_get(var);
  37
  38         if (s == NULL)
  39                 return -1;
  40         return (*s == '1' || *s == 'y' || *s == 'Y' || *s == 't' || *s == 'T') ?
  41                 1 : 0;
  42 }
  43
  44 /*
  45  * Look up the variable from the default environment
  46  */
  47 char *env_get_default(const char *name)
  48 {
  49         char *ret_val;
  50         unsigned long really_valid = gd->env_valid;
  51         unsigned long real_gd_flags = gd->flags;
  52
  53         /* Pretend that the image is bad. */
  54         gd->flags &= ~GD_FLG_ENV_READY;
  55         gd->env_valid = ENV_INVALID;
  56         ret_val = env_get(name);
  57         gd->env_valid = really_valid;
  58         gd->flags = real_gd_flags;
  59         return ret_val;
  60 }
  61
  62 void set_default_env(const char *s)
  63 {
  64         int flags = 0;
  65
  66         if (sizeof(default_environment) > ENV_SIZE) {
  67                 puts("*** Error - default environment is too large\n\n");
  68                 return;
  69         }
  70
  71         if (s) {
  72                 if (*s == '!') {
  73                         printf("*** Warning - %s, "
  74                                 "using default environment\n\n",
  75                                 s + 1);
  76                 } else {
  77                         flags = H_INTERACTIVE;
  78                         puts(s);
  79                 }
  80         } else {
  81                 debug("Using default environment\n");
  82         }
  83
  84         if (himport_r(&env_htab, (char *)default_environment,
  85                         sizeof(default_environment), '\0', flags, 0,
  86                         0, NULL) == 0)
  87                 pr_err("Environment import failed: errno = %d\n", errno);
  88
  89         gd->flags |= GD_FLG_ENV_READY;
  90         gd->flags |= GD_FLG_ENV_DEFAULT;
  91 }
  92
  93
  94 /* [re]set individual variables to their value in the default environment */
  95 int set_default_vars(int nvars, char * const vars[])
  96 {
  97         /*
  98          * Special use-case: import from default environment
  99          * (and use \0 as a separator)
 100          */
 101         return himport_r(&env_htab, (const char *)default_environment,
 102                                 sizeof(default_environment), '\0',
 103                                 H_NOCLEAR | H_INTERACTIVE, 0, nvars, vars);
 104 }
 105
 106 /*
 107  * Check if CRC is valid and (if yes) import the environment.
 108  * Note that "buf" may or may not be aligned.
 109  */
 110 int env_import(const char *buf, int check)
 111 {
 112         env_t *ep = (env_t *)buf;
 113
 114         if (check) {
 115                 uint32_t crc;
 116
 117                 memcpy(&crc, &ep->crc, sizeof(crc));
 118
 119                 if (crc32(0, ep->data, ENV_SIZE) != crc) {
 120                         set_default_env("!bad CRC");
 121                         return 0;
 122                 }
 123         }
 124
 125         if (himport_r(&env_htab, (char *)ep->data, ENV_SIZE, '\0', 0, 0,
 126                         0, NULL)) {
 127                 gd->flags |= GD_FLG_ENV_READY;
 128                 return 1;
 129         }
 130
 131         pr_err("Cannot import environment: errno = %d\n", errno);
 132
 133         set_default_env("!import failed");
 134
 135         return 0;
 136 }
 137
 138 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 139 static unsigned char env_flags;
 140
 141 int env_import_redund(const char *buf1, const char *buf2)
 142 {
 143         int crc1_ok, crc2_ok;
 144         env_t *ep, *tmp_env1, *tmp_env2;
 145
 146         tmp_env1 = (env_t *)buf1;
 147         tmp_env2 = (env_t *)buf2;
 148
 149         crc1_ok = crc32(0, tmp_env1->data, ENV_SIZE) ==
 150                         tmp_env1->crc;
 151         crc2_ok = crc32(0, tmp_env2->data, ENV_SIZE) ==
 152                         tmp_env2->crc;
 153
 154         if (!crc1_ok && !crc2_ok) {
 155                 set_default_env("!bad CRC");
 156                 return 0;
 157         } else if (crc1_ok && !crc2_ok) {
 158                 gd->env_valid = ENV_VALID;
 159         } else if (!crc1_ok && crc2_ok) {
 160                 gd->env_valid = ENV_REDUND;
 161         } else {
 162                 /* both ok - check serial */
 163                 if (tmp_env1->flags == 255 && tmp_env2->flags == 0)
 164                         gd->env_valid = ENV_REDUND;
 165                 else if (tmp_env2->flags == 255 && tmp_env1->flags == 0)
 166                         gd->env_valid = ENV_VALID;
 167                 else if (tmp_env1->flags > tmp_env2->flags)
 168                         gd->env_valid = ENV_VALID;
 169                 else if (tmp_env2->flags > tmp_env1->flags)
 170                         gd->env_valid = ENV_REDUND;
 171                 else /* flags are equal - almost impossible */
 172                         gd->env_valid = ENV_VALID;
 173         }
 174
 175         if (gd->env_valid == ENV_VALID)
 176                 ep = tmp_env1;
 177         else
 178                 ep = tmp_env2;
 179
 180         env_flags = ep->flags;
 181         return env_import((char *)ep, 0);
 182 }
 183 #endif /* CONFIG_SYS_REDUNDAND_ENVIRONMENT */
 184
 185 /* Export the environment and generate CRC for it. */
 186 int env_export(env_t *env_out)
 187 {
 188         char *res;
 189         ssize_t len;
 190
 191         res = (char *)env_out->data;
 192         len = hexport_r(&env_htab, '\0', 0, &res, ENV_SIZE, 0, NULL);
 193         if (len < 0) {
 194                 pr_err("Cannot export environment: errno = %d\n", errno);
 195                 return 1;
 196         }
 197
 198         env_out->crc = crc32(0, env_out->data, ENV_SIZE);
 199
 200 #ifdef CONFIG_SYS_REDUNDAND_ENVIRONMENT
 201         env_out->flags = ++env_flags; /* increase the serial */
 202 #endif
 203
 204         return 0;
 205 }
 206
 207 void env_relocate(void)
 208 {
 209 #if defined(CONFIG_NEEDS_MANUAL_RELOC)
 210         env_reloc();
 211         env_htab.change_ok += gd->reloc_off;
 212 #endif
 213         if (gd->env_valid == ENV_INVALID) {
 214 #if defined(CONFIG_ENV_IS_NOWHERE) || defined(CONFIG_SPL_BUILD)
 215                 /* Environment not changable */
 216                 set_default_env(NULL);
 217 #else
 218                 bootstage_error(BOOTSTAGE_ID_NET_CHECKSUM);
 219                 set_default_env("!bad CRC");
 220 #endif
 221         } else {
 222                 env_load();
 223         }
 224 }
 225
 226 #if defined(CONFIG_AUTO_COMPLETE) && !defined(CONFIG_SPL_BUILD)
 227 int env_complete(char *var, int maxv, char *cmdv[], int bufsz, char *buf)
 228 {
 229         ENTRY *match;
 230         int found, idx;
 231
 232         idx = 0;
 233         found = 0;
 234         cmdv[0] = NULL;
 235
 236         while ((idx = hmatch_r(var, idx, &match, &env_htab))) {
 237                 int vallen = strlen(match->key) + 1;
 238
 239                 if (found >= maxv - 2 || bufsz < vallen)
 240                         break;
 241
 242                 cmdv[found++] = buf;
 243                 memcpy(buf, match->key, vallen);
 244                 buf += vallen;
 245                 bufsz -= vallen;
 246         }
 247
 248         qsort(cmdv, found, sizeof(cmdv[0]), strcmp_compar);
 249
 250         if (idx)
 251                 cmdv[found++] = "...";
 252
 253         cmdv[found] = NULL;
 254         return found;
 255 }
 256 #endif