/* xputenv.c: set an environment variable without return. */ /* * Copyright 2003-05 Olaf Weber. * Copyright 1993-98 Karl Berry. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #ifdef WIN32 #include #else /* Avoid implicit declaration warning. But since some systems do declare it, don't use a prototype, for fear of conflicts. */ extern int putenv (); #endif /* not WIN32 */ /* These record the strings we've set and have to keep around. * This function can be called many times during a run, and this * allows us to reclaim memory we allocated. */ static const char **saved_env; static int saved_count; /* * We have different arguments from the "standard" function. A separate * var and value tends to be much more practical. * * The standards for putenv are clear: put the passed string into the * environment, and if you alter that string, the environment changes. * Of course various implementations are broken in a number of ways, * which include making copies of the passed string, and more. */ void xputenv(const char *var, const char *value) { char *cur_item; char *old_item; char *new_item; size_t var_lim; int cur_loc; /* kpse_debug2(KPSE_DEBUG_VARS, "kpse_putenv($%s,%s)", var, value); */ old_item = NULL; cur_item = concat3(var, "=", value); /* Include '=' in length. */ var_lim = strlen(var) + 1; /* Have we stored something for this value already? */ for (cur_loc = 0; cur_loc != saved_count; ++cur_loc) { if (strncmp(saved_env[cur_loc], cur_item, var_lim) == 0) { /* Get the old value. We need this is case another part * of the program didn't use us to change the environment. */ old_item = getenv(var); break; } } if (old_item && strcmp(old_item, cur_item+var_lim) == 0) { /* Set same value as is in environment, don't bother to set. */ free(cur_item); return; } else { /* We set a different value. */ if (putenv(cur_item) < 0) FATAL1("putenv(%s)", cur_item); /* Get the new string. */ new_item = getenv(var); if (new_item != cur_item+var_lim) { /* Our new string isn't used, don't keep it around. */ free(cur_item); return; } } /* If we get here, it means getenv() returned a reference to cur_item. * So we save cur_item, and free the old string we also owned. */ if (cur_loc == saved_count) { /* No old string. */ saved_count++; saved_env = XRETALLOC(saved_env, saved_count, const char *); } else { /* We owned the old string. */ free(saved_env[cur_loc]); } saved_env[cur_loc] = cur_item; return; } /* A special case for setting a variable to a numeric value (specifically, KPATHSEA_DPI). We don't need to dynamically allocate and free the string for the number, since it's saved as part of the environment value. */ void xputenv_int P2C(const_string, var_name, int, num) { char str[MAX_INT_LENGTH]; sprintf (str, "%d", num); xputenv (var_name, str); }