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#include <u.h>
#include <libc.h>
char*
getenv(char *name)
{
enum { HUNK = 100, };
char *s, *p;
int f, r, n;
if(name[0]=='\0' || strcmp(name, ".")==0 || strcmp(name, "..")==0 || strchr(name, '/')!=nil
|| strlen(name) >= HUNK-5){
werrstr("bad env name: %s", name);
return nil;
}
if((s = malloc(HUNK)) == nil)
return nil;
snprint(s, HUNK, "/env/%s", name);
n = 0;
r = -1;
if((f = open(s, OREAD)) >= 0){
while((r = read(f, s+n, HUNK)) > 0){
n += r;
r = -1;
if((p = realloc(s, n+HUNK)) == nil)
break;
s = p;
}
close(f);
}
if(r < 0 || (p = realloc(s, n+1)) == nil){
free(s);
return nil;
}
s = p;
setmalloctag(s, getcallerpc(&name));
while(n > 0 && s[n-1] == '\0')
n--;
s[n] = '\0';
while(--n >= 0){
if(s[n] == '\0')
s[n] = ' ';
}
return s;
}
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