ref: c7d9da8f5a41b833946027c802e0e8d7dd014b22
dir: /sys/src/cmd/upas/common/aux.c/
#include "common.h" /* * check for shell characters in a String */ static char *illegalchars = "\r\n"; extern int shellchars(char *cp) { char *sp; for(sp=illegalchars; *sp; sp++) if(strchr(cp, *sp)) return 1; return 0; } static char *specialchars = " ()<>{};=\\'\`^&|"; static char *escape = "%%"; int hexchar(int x) { x &= 0xf; if(x < 10) return '0' + x; else return 'A' + x - 10; } /* * rewrite a string to escape shell characters */ extern String* escapespecial(String *s) { String *ns; char *sp; for(sp = specialchars; *sp; sp++) if(strchr(s_to_c(s), *sp)) break; if(*sp == 0) return s; ns = s_new(); for(sp = s_to_c(s); *sp; sp++){ if(strchr(specialchars, *sp)){ s_append(ns, escape); s_putc(ns, hexchar(*sp>>4)); s_putc(ns, hexchar(*sp)); } else s_putc(ns, *sp); } s_terminate(ns); s_free(s); return ns; } uint hex2uint(char x) { if(x >= '0' && x <= '9') return x - '0'; if(x >= 'A' && x <= 'F') return (x - 'A') + 10; if(x >= 'a' && x <= 'f') return (x - 'a') + 10; return -512; } /* * rewrite a string to remove shell characters escapes */ extern String* unescapespecial(String *s) { char *sp; uint c, n; String *ns; if(strstr(s_to_c(s), escape) == 0) return s; n = strlen(escape); ns = s_new(); for(sp = s_to_c(s); *sp; sp++){ if(strncmp(sp, escape, n) == 0){ c = (hex2uint(sp[n])<<4) | hex2uint(sp[n+1]); if(c & 0x80) s_putc(ns, *sp); else { s_putc(ns, c); sp += n+2-1; } } else s_putc(ns, *sp); } s_terminate(ns); s_free(s); return ns; } int returnable(char *path) { return strcmp(path, "/dev/null") != 0; } int temperror(void) { char err[ERRMAX]; rerrstr(err, sizeof(err)); return strstr(err, "too much activity") != nil || strstr(err, "temporary problem") != nil; }