minix/commands/simple/chmod.c

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2005-04-21 16:53:53 +02:00
/* chmod - Change file modes Author: V. Archer */
/* Copyright 1991 by Vincent Archer
* You may freely redistribute this software, in source or binary
* form, provided that you do not alter this copyright mention in any
* way.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <minix/minlib.h>
#include <stdio.h>
#ifndef S_ISLNK
#define S_ISLNK(mode) 0
#define lstat stat
#endif
#define USR_MODES (S_ISUID|S_IRWXU)
#define GRP_MODES (S_ISGID|S_IRWXG)
#define EXE_MODES (S_IXUSR|S_IXGRP|S_IXOTH)
#ifdef S_ISVTX
#define ALL_MODES (USR_MODES|GRP_MODES|S_IRWXO|S_ISVTX)
#else
#define ALL_MODES (USR_MODES|GRP_MODES|S_IRWXO)
#endif
/* Common variables */
char *symbolic;
mode_t new_mode, u_mask;
int rflag, errors;
struct stat st;
char path[PATH_MAX + 1];
_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(mode_t parsemode, (char *symbolic, Mode_t oldmode));
_PROTOTYPE(int do_change, (char *name));
_PROTOTYPE(void usage, (void));
/* Parse a P1003.2 4.7.7-conformant symbolic mode. */
mode_t parsemode(symbolic, oldmode)
char *symbolic;
mode_t oldmode;
{
mode_t who, mask, newmode, tmpmask;
char action;
newmode = oldmode & ALL_MODES;
while (*symbolic) {
who = 0;
for (; *symbolic; symbolic++) {
if (*symbolic == 'a') {
who |= ALL_MODES;
continue;
}
if (*symbolic == 'u') {
who |= USR_MODES;
continue;
}
if (*symbolic == 'g') {
who |= GRP_MODES;
continue;
}
if (*symbolic == 'o') {
who |= S_IRWXO;
continue;
}
break;
}
if (!*symbolic || *symbolic == ',') usage();
while (*symbolic) {
if (*symbolic == ',') break;
switch (*symbolic) {
default:
usage();
case '+':
case '-':
case '=': action = *symbolic++;
}
mask = 0;
for (; *symbolic; symbolic++) {
if (*symbolic == 'u') {
tmpmask = newmode & S_IRWXU;
mask |= tmpmask | (tmpmask << 3) | (tmpmask << 6);
symbolic++;
break;
}
if (*symbolic == 'g') {
tmpmask = newmode & S_IRWXG;
mask |= tmpmask | (tmpmask >> 3) | (tmpmask << 3);
symbolic++;
break;
}
if (*symbolic == 'o') {
tmpmask = newmode & S_IRWXO;
mask |= tmpmask | (tmpmask >> 3) | (tmpmask >> 6);
symbolic++;
break;
}
if (*symbolic == 'r') {
mask |= S_IRUSR | S_IRGRP | S_IROTH;
continue;
}
if (*symbolic == 'w') {
mask |= S_IWUSR | S_IWGRP | S_IWOTH;
continue;
}
if (*symbolic == 'x') {
mask |= EXE_MODES;
continue;
}
if (*symbolic == 's') {
mask |= S_ISUID | S_ISGID;
continue;
}
if (*symbolic == 'X') {
if (S_ISDIR(oldmode) || (oldmode & EXE_MODES))
mask |= EXE_MODES;
continue;
}
#ifdef S_ISVTX
if (*symbolic == 't') {
mask |= S_ISVTX;
who |= S_ISVTX;
continue;
}
#endif
break;
}
switch (action) {
case '=':
if (who)
newmode &= ~who;
else
newmode = 0;
case '+':
if (who)
newmode |= who & mask;
else
newmode |= mask & (~u_mask);
break;
case '-':
if (who)
newmode &= ~(who & mask);
else
newmode &= ~mask | u_mask;
}
}
if (*symbolic) symbolic++;
}
return(newmode);
}
/* Main module. The single option possible (-R) does not warrant a call to
* the getopt() stuff.
*/
int main(argc, argv)
int argc;
char *argv[];
{
int ex_code = 0;
argc--;
argv++;
if (argc && strcmp(*argv, "-R") == 0) {
argc--;
argv++;
rflag = 1;
} else
rflag = 0;
if (!argc--) usage();
if (!strcmp(argv[0], "--")) { /* Allow chmod -- -r, as in Draft11 example */
if (!argc--) usage();
argv++;
}
symbolic = *argv++;
if (!argc) usage();
if (*symbolic >= '0' && *symbolic <= '7') {
new_mode = 0;
while (*symbolic >= '0' && *symbolic <= '7')
new_mode = (new_mode << 3) | (*symbolic++ & 07);
if (*symbolic) usage();
new_mode &= ALL_MODES;
symbolic = (char *) 0;
} else
u_mask = umask(0);
while (argc--)
if (do_change(*argv++)) ex_code = 1;
return(ex_code);
}
/* Apply a mode change to a given file system element. */
int do_change(name)
char *name;
{
mode_t m;
DIR *dirp;
struct dirent *entp;
char *namp;
if (lstat(name, &st)) {
perror(name);
return(1);
}
if (S_ISLNK(st.st_mode) && rflag) return(0); /* Note: violates POSIX. */
if (!symbolic)
m = new_mode;
else
m = parsemode(symbolic, st.st_mode);
if (chmod(name, m)) {
perror(name);
errors = 1;
} else
errors = 0;
if (S_ISDIR(st.st_mode) && rflag) {
if (!(dirp = opendir(name))) {
perror(name);
return(1);
}
if (name != path) strcpy(path, name);
namp = path + strlen(path);
*namp++ = '/';
while (entp = readdir(dirp))
if (entp->d_name[0] != '.' ||
(entp->d_name[1] &&
(entp->d_name[1] != '.' || entp->d_name[2]))) {
strcpy(namp, entp->d_name);
errors |= do_change(path);
}
closedir(dirp);
*--namp = '\0';
}
return(errors);
}
/* Display Posix prototype */
void usage()
{
std_err("Usage: chmod [-R] mode file...\n");
exit(1);
}