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scandir(3) previously used st_size 

to obtain an initial estimate of the array length needed to store all
the directory entries. Although BSD has historically guaranteed that
st_size is the size of the directory file, POSIX does not, and more to
the point, some recent filesystems such as ZFS use st_size to mean
something else.

The fix is to not stat the directory at all, set the initial
array size to 32 entries, and realloc it in powers of 2 if that
proves insufficient.

PR:	113668
This commit is contained in:
das 2008-03-16 19:08:53 +00:00 committed by Sebastian Huber
parent d785551a46
commit 2d3c2f4697
1 changed files with 34 additions and 56 deletions
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90
newlib/libc/posix/scandir.c
View File

@ -42,8 +42,6 @@ __FBSDID("$FreeBSD$");
* struct dirent (through namelist). Returns -1 if there were any errors.
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <stddef.h>
#include <dirent.h>
#include <stdlib.h>
@ -71,41 +69,22 @@ scandir(const char *dirname, struct dirent ***namelist,
int (*select)(const struct dirent *), int (*dcomp)(const struct dirent **,
const struct dirent **))
{
register struct dirent *d, *p, **names;
register size_t nitems;
struct stat stb;
long arraysz;
register struct dirent *d, *p, **names = NULL;
register size_t arraysz, numitems;
DIR *dirp;
int successful = 0;
int rc = 0;
dirp = NULL;
names = NULL;
if ((dirp = opendir(dirname)) == NULL)
return(-1);
#ifdef HAVE_DD_LOCK
__lock_acquire_recursive(dirp->dd_lock);
#endif
if (fstat(dirp->dd_fd, &stb) < 0)
goto cleanup;
/*
* If there were no directory entries, then bail.
*/
if (stb.st_size == 0)
goto cleanup;
/*
* estimate the array size by taking the size of the directory file
* and dividing it by a multiple of the minimum size entry.
*/
arraysz = (stb.st_size / 24);
numitems = 0;
arraysz = 32; /* initial estimate of the array size */
names = (struct dirent **)malloc(arraysz * sizeof(struct dirent *));
if (names == NULL)
goto cleanup;
goto fail;
nitems = 0;
while ((d = readdir(dirp)) != NULL) {
if (select != NULL && !(*select)(d))
continue; /* just selected names */
@ -114,7 +93,7 @@ scandir(const char *dirname, struct dirent ***namelist,
*/
p = (struct dirent *)malloc(DIRSIZ(d));
if (p == NULL)
goto cleanup;
goto fail;
p->d_ino = d->d_ino;
p->d_reclen = d->d_reclen;
#ifdef _DIRENT_HAVE_D_NAMLEN
@ -127,39 +106,38 @@ scandir(const char *dirname, struct dirent ***namelist,
* Check to make sure the array has space left and
* realloc the maximum size.
*/
if (++nitems >= arraysz) {
if (fstat(dirp->dd_fd, &stb) < 0)
goto cleanup;
arraysz = stb.st_size / 12;
names = (struct dirent **)reallocf((char *)names,
arraysz * sizeof(struct dirent *));
if (names == NULL)
goto cleanup;
}
names[nitems-1] = p;
}
successful = 1;
cleanup:
closedir(dirp);
if (successful) {
if (nitems && dcomp != NULL)
qsort(names, nitems, sizeof(struct dirent *), (void *)dcomp);
*namelist = names;
rc = nitems;
} else { /* We were unsuccessful, clean up storage and return -1. */
if ( names ) {
int i;
for (i=0; i < nitems; i++ )
free( names[i] );
free( names );
}
rc = -1;
}
if (numitems >= arraysz) {
struct dirent **names2;
names2 = reallocarray(names, arraysz,
2 * sizeof(struct dirent *));
if (names2 == NULL) {
free(p);
goto fail;
}
names = names2;
arraysz *= 2;
}
names[numitems++] = p;
}
closedir(dirp);
if (numitems && dcomp != NULL)
qsort(names, numitems, sizeof(struct dirent *), (void *)dcomp);
*namelist = names;
#ifdef HAVE_DD_LOCK
__lock_release_recursive(dirp->dd_lock);
#endif
return(rc);
return (numitems);
fail:
while (numitems > 0)
free(names[--numitems]);
free(names);
closedir(dirp);
#ifdef HAVE_DD_LOCK
__lock_release_recursive(dirp->dd_lock);
#endif
return (-1);
}
/*