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Kernel+LibC: Don't crash upon traversal of large directories.

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This commit is contained in:
Andreas Kling 2019-03-20 18:31:12 +01:00
parent 7b32afdcfc
commit 86e2348b74
2 changed files with 16 additions and 7 deletions
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13
LibC/dirent.cpp
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@ -5,6 +5,9 @@
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <AK/StdLibExtras.h>
#include <Kernel/Syscall.h>
extern "C" {
@ -54,9 +57,13 @@ dirent* readdir(DIR* dirp)
return nullptr;
if (!dirp->buffer) {
// FIXME: Figure out how much to actually allocate.
dirp->buffer = (char*)malloc(4096);
ssize_t nread = syscall(SC_get_dir_entries, dirp->fd, dirp->buffer, 4096);
struct stat st;
int rc = fstat(dirp->fd, &st);
if (rc < 0)
return nullptr;
size_t size_to_allocate = max(st.st_size, 4096);
dirp->buffer = (char*)malloc(size_to_allocate);
ssize_t nread = syscall(SC_get_dir_entries, dirp->fd, dirp->buffer, size_to_allocate);
dirp->buffer_size = nread;
dirp->nextptr = dirp->buffer;
}