71 lines
1.7 KiB
C
71 lines
1.7 KiB
C
/*
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* This file is part of Jehanne.
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*
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* Copyright (C) 2017 Giacomo Tesio <giacomo@tesio.it>
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*
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* Jehanne is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2 of the License.
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*
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* Jehanne is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Jehanne. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <u.h>
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#include <libc.h>
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char*
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getenv(const char *name)
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{
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int f;
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int32_t l;
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char path[127+5+1], *value;
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assert(name != nil);
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if(name[0]=='\0')
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goto BadName;
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if(strcmp(name, ".")==0 || strcmp(name, "..")==0)
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goto BadName;
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if(strchr(name, '/')!=nil)
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goto BadName;
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snprint(path, sizeof path, "/env/%s", name);
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if(strcmp(path+5, name) != 0)
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goto BadName;
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f = open(path, OREAD);
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if(f < 0){
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/* try with #e, in case of a previous rfork(RFCNAMEG)
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*
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* NOTE: /env is bound to #ec by default, so we
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* cannot simply use always #e instead of /env. Also
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* using #ec when the open in #e fails is both
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* slow and not flexible enough.
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*/
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snprint(path, sizeof path, "#e/%s", name);
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f = open(path, OREAD);
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if(f < 0)
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return nil;
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}
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l = seek(f, 0, 2);
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value = malloc(l+1);
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if(value == nil)
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goto Done;
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setmalloctag(value, getcallerpc());
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seek(f, 0, 0);
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if(read(f, value, l) >= 0)
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value[l] = '\0';
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Done:
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close(f);
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return value;
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BadName:
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werrstr("bad env name: '%s'", name);
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return nil;
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}
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