sbase/util/mode.c

163 lines
3.0 KiB
C

#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include "../util.h"
mode_t
getumask(void)
{
mode_t mask = umask(0);
umask(mask);
return mask;
}
mode_t
parsemode(const char *str, mode_t mode, mode_t mask)
{
char *end;
const char *p = str;
int octal, op;
mode_t who, perm, clear;
octal = strtol(str, &end, 8);
if(*end == '\0') {
if(octal < 0 || octal > 07777) {
eprintf("%s: invalid mode\n", str);
return -1;
}
mode = 0;
if(octal & 04000) mode |= S_ISUID;
if(octal & 02000) mode |= S_ISGID;
if(octal & 01000) mode |= S_ISVTX;
if(octal & 00400) mode |= S_IRUSR;
if(octal & 00200) mode |= S_IWUSR;
if(octal & 00100) mode |= S_IXUSR;
if(octal & 00040) mode |= S_IRGRP;
if(octal & 00020) mode |= S_IWGRP;
if(octal & 00010) mode |= S_IXGRP;
if(octal & 00004) mode |= S_IROTH;
if(octal & 00002) mode |= S_IWOTH;
if(octal & 00001) mode |= S_IXOTH;
return mode;
}
next:
/* first, determine which bits we will be modifying */
for(who = 0; *p; p++) {
switch(*p) {
/* masks */
case 'u':
who |= S_IRWXU|S_ISUID;
continue;
case 'g':
who |= S_IRWXG|S_ISGID;
continue;
case 'o':
who |= S_IRWXO;
continue;
case 'a':
who |= S_IRWXU|S_ISUID|S_IRWXG|S_ISGID|S_IRWXO;
continue;
}
break;
}
if(who) {
clear = who;
} else {
clear = S_ISUID|S_ISGID|S_ISVTX|S_IRWXU|S_IRWXG|S_IRWXO;
who = ~mask;
}
while(*p) {
switch(*p) {
/* opers */
case '=':
case '+':
case '-':
op = (int)*p;
break;
default:
eprintf("%s: invalid mode\n", str);
return -1;
}
perm = 0;
switch(*++p) {
/* copy */
case 'u':
if(mode & S_IRUSR)
perm |= S_IRUSR|S_IRGRP|S_IROTH;
if(mode & S_IWUSR)
perm |= S_IWUSR|S_IWGRP|S_IWOTH;
if(mode & S_IXUSR)
perm |= S_IXUSR|S_IXGRP|S_IXOTH;
if(mode & S_ISUID)
perm |= S_ISUID|S_ISGID;
p++;
break;
case 'g':
if(mode & S_IRGRP)
perm |= S_IRUSR|S_IRGRP|S_IROTH;
if(mode & S_IWGRP)
perm |= S_IWUSR|S_IWGRP|S_IWOTH;
if(mode & S_IXGRP)
perm |= S_IXUSR|S_IXGRP|S_IXOTH;
if(mode & S_ISGID)
perm |= S_ISUID|S_ISGID;
p++;
break;
case 'o':
if(mode & S_IROTH)
perm |= S_IRUSR|S_IRGRP|S_IROTH;
if(mode & S_IWOTH)
perm |= S_IWUSR|S_IWGRP|S_IWOTH;
if(mode & S_IXOTH)
perm |= S_IXUSR|S_IXGRP|S_IXOTH;
p++;
break;
default:
for(; *p; p++) {
switch(*p) {
/* modes */
case 'r':
perm |= S_IRUSR|S_IRGRP|S_IROTH;
break;
case 'w':
perm |= S_IWUSR|S_IWGRP|S_IWOTH;
break;
case 'x':
perm |= S_IXUSR|S_IXGRP|S_IXOTH;
break;
case 's':
perm |= S_ISUID|S_ISGID;
break;
case 't':
perm |= S_ISVTX;
break;
default:
goto apply;
}
}
}
apply:
/* apply */
switch(op) {
case '=':
mode &= ~clear;
/* fallthrough */
case '+':
mode |= perm & who;
break;
case '-':
mode &= ~(perm & who);
break;
}
/* if we hit a comma, move on to the next clause */
if(*p == ',') {
p++;
goto next;
}
}
return mode;
}