ref: ff4daa7e93f4ea09506276ecdb69fa1cca19a7a7
dir: /sys/src/libc/9sys/putenv.c/
#include <u.h> #include <libc.h> int putenv(char *name, char *val) { int f; char ename[100]; long s; if(strchr(name, '/') != nil) return -1; snprint(ename, sizeof ename, "/env/%s", name); if(strcmp(ename+5, name) != 0) return -1; f = create(ename, OWRITE, 0664); if(f < 0) return -1; s = strlen(val); if(write(f, val, s) != s){ close(f); return -1; } close(f); return 0; }