101 lines
2.0 KiB
C
101 lines
2.0 KiB
C
/* @(#)issubdir.c 1.1 94/10/31 Copyr 1987 Sun Micro */
|
|
|
|
/*
|
|
* Subdirectory detection: needed by exportfs and rpc.mountd.
|
|
* The above programs call issubdir() frequently, so we make
|
|
* it fast by caching the results of stat().
|
|
*/
|
|
#include <sys/param.h>
|
|
#include <sys/stat.h>
|
|
#include <string.h>
|
|
|
|
#define MAXSTATS 20 /* maximum number of stat()'s to save */
|
|
|
|
#define inoeq(ino1, ino2) ((ino1) == (ino2))
|
|
#define deveq(dev1, dev2) ((dev1) == (dev2))
|
|
|
|
/*
|
|
* dir1 is a subdirectory of dir2 within the same filesystem if
|
|
* (a) dir1 is identical to dir2
|
|
* (b) dir1's parent is dir2
|
|
*/
|
|
issubdir(dir1, dir2)
|
|
char *dir1;
|
|
char *dir2;
|
|
{
|
|
struct stat st;
|
|
char *p;
|
|
int index;
|
|
dev_t parent_dev;
|
|
ino_t parent_ino;
|
|
|
|
static dev_t child_dev;
|
|
static ino_t child_ino[MAXSTATS];
|
|
static int valid;
|
|
static char childdir[MAXPATHLEN];
|
|
|
|
/*
|
|
* Get parent directory info
|
|
*/
|
|
if (stat(dir2, &st) < 0) {
|
|
return(0);
|
|
}
|
|
parent_dev = st.st_dev;
|
|
parent_ino = st.st_ino;
|
|
|
|
if (strcmp(childdir, dir1) != 0) {
|
|
/*
|
|
* Not in cache: get child directory info
|
|
*/
|
|
p = strcpy(childdir, dir1) + strlen(dir1);
|
|
index = 0;
|
|
valid = 0;
|
|
for (;;) {
|
|
if (stat(childdir, &st) < 0) {
|
|
childdir[0] = 0; /* invalidate cache */
|
|
return (0);
|
|
}
|
|
if (index == 0) {
|
|
child_dev = st.st_dev;
|
|
}
|
|
if (index > 0 &&
|
|
(child_dev != st.st_dev ||
|
|
inoeq(child_ino[index - 1], st.st_ino))) {
|
|
/*
|
|
* Hit root: done
|
|
*/
|
|
break;
|
|
}
|
|
child_ino[index++] = st.st_ino;
|
|
if (st.st_mode & S_IFDIR) {
|
|
p = strcpy(p, "/..") + 3;
|
|
} else {
|
|
p = strrchr(childdir, '/');
|
|
if (p == NULL) {
|
|
p = strcpy(childdir, ".") + 1;
|
|
} else {
|
|
while (&p[1] >childdir && p[1] == '/') {
|
|
p--;
|
|
}
|
|
*p = 0;
|
|
}
|
|
}
|
|
}
|
|
valid = index;
|
|
(void) strcpy(childdir, dir1);
|
|
}
|
|
|
|
/*
|
|
* Perform the test
|
|
*/
|
|
if (!deveq(parent_dev, child_dev)) {
|
|
return (0);
|
|
}
|
|
for (index = 0; index < valid; index++) {
|
|
if (inoeq(child_ino[index], parent_ino)) {
|
|
return (1);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|