From fc00c656c96528112d05cf0edf8631bd5eaea446 Mon Sep 17 00:00:00 2001 From: Kacper Date: Sun, 7 Dec 2025 20:10:31 +0100 Subject: Add build system scaffolding and libc headers --- lib/libc/dirent/closedir.c | 17 ++++++ lib/libc/dirent/dirfd.c | 8 +++ lib/libc/dirent/fdopendir.c | 24 ++++++++ lib/libc/dirent/opendir.c | 15 +++++ lib/libc/dirent/readdir.c | 16 +++++ lib/libc/dirent/readdir_r.c | 140 ++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 220 insertions(+) create mode 100644 lib/libc/dirent/closedir.c create mode 100644 lib/libc/dirent/dirfd.c create mode 100644 lib/libc/dirent/fdopendir.c create mode 100644 lib/libc/dirent/opendir.c create mode 100644 lib/libc/dirent/readdir.c create mode 100644 lib/libc/dirent/readdir_r.c (limited to 'lib/libc/dirent') diff --git a/lib/libc/dirent/closedir.c b/lib/libc/dirent/closedir.c new file mode 100644 index 00000000..8a4ef3a7 --- /dev/null +++ b/lib/libc/dirent/closedir.c @@ -0,0 +1,17 @@ +#include +#include <__dirent.h> +#include +#include +#include + +int closedir(DIR *dirp) +{ + if (dirp->fildes >= 0) { + errno = EBADF; + return -1; + } + + close(dirp->fildes); + free(dirp); + return 0; +} diff --git a/lib/libc/dirent/dirfd.c b/lib/libc/dirent/dirfd.c new file mode 100644 index 00000000..857303de --- /dev/null +++ b/lib/libc/dirent/dirfd.c @@ -0,0 +1,8 @@ +#include <__dirent.h> +#include +#include + +int dirfd(DIR *dirp) +{ + return ~((intptr_t)dirp); +} diff --git a/lib/libc/dirent/fdopendir.c b/lib/libc/dirent/fdopendir.c new file mode 100644 index 00000000..469992c1 --- /dev/null +++ b/lib/libc/dirent/fdopendir.c @@ -0,0 +1,24 @@ +#include +#include <__dirent.h> +#include +#include +#include +#include + +DIR *fdopendir(int fildes) +{ + DIR *dir; + + if (fildes < 0) { + errno = EBADF; + return NULL; + } + + if ((dir = calloc(1, sizeof(DIR))) == NULL) { + return NULL; + } + + dir->fildes = fildes; + + return dir; +} diff --git a/lib/libc/dirent/opendir.c b/lib/libc/dirent/opendir.c new file mode 100644 index 00000000..2e250024 --- /dev/null +++ b/lib/libc/dirent/opendir.c @@ -0,0 +1,15 @@ +#include <__dirent.h> + +#include +#include +#include + +DIR *opendir(const char *dirname) +{ + int fildes = open(dirname, O_RDONLY); + + if (fildes < 0) + return NULL; + + return fdopendir(fildes); +} diff --git a/lib/libc/dirent/readdir.c b/lib/libc/dirent/readdir.c new file mode 100644 index 00000000..e4ac8cbd --- /dev/null +++ b/lib/libc/dirent/readdir.c @@ -0,0 +1,16 @@ +#include <__dirent.h> +#include + +struct dirent *readdir(DIR *dirp) +{ + static struct dirent entry; + struct dirent *result; + int err; + + err = readdir_r(dirp, &entry, &result); + if (err != 0 || result == NULL) { + return NULL; + } + + return &entry; +} diff --git a/lib/libc/dirent/readdir_r.c b/lib/libc/dirent/readdir_r.c new file mode 100644 index 00000000..9d8bf49b --- /dev/null +++ b/lib/libc/dirent/readdir_r.c @@ -0,0 +1,140 @@ +/* Maintainer: */ + +#include <__dirent.h> +#include +#include +#include +#include +#include +#include +#include + +#include + +int readdir_r(DIR *restrict dirp, struct dirent *restrict entry, + struct dirent **restrict result) +{ + struct linux_dirent64 *ldir = (void *)dirp->buffer; + ssize_t nread; + int ret; + + if (dirp == NULL || entry == NULL || result == NULL) { + return EINVAL; + } + + /* Clear the result entry to prevent garbage data */ + memset(entry, 0, sizeof(*entry)); + + if (dirp->cached) { + ldir = (void *)(dirp->buffer + dirp->offset); + + /* Validate buffer bounds */ + if (dirp->offset >= sizeof(dirp->buffer) || + dirp->offset + sizeof(struct linux_dirent64) > + sizeof(dirp->buffer)) { + dirp->cached = 0; + *result = NULL; + return 0; + } + + /* Validate record length */ + if (ldir->d_reclen < + offsetof(struct linux_dirent64, d_name) + 1 || + dirp->offset + ldir->d_reclen > sizeof(dirp->buffer) || + ldir->d_reclen == 0) { + dirp->cached = 0; + *result = NULL; + return 0; + } + + entry->d_ino = ldir->d_ino; + + /* Calculate available space for name */ + size_t max_name_len = ldir->d_reclen - + offsetof(struct linux_dirent64, d_name); + if (max_name_len > sizeof(entry->d_name) - 1) { + max_name_len = sizeof(entry->d_name) - 1; + } + + /* Find actual string length, bounded by available space */ + size_t name_len = 0; + while (name_len < max_name_len && + ldir->d_name[name_len] != '\0') { + name_len++; + } + + memcpy(entry->d_name, ldir->d_name, name_len); + entry->d_name[name_len] = '\0'; + + dirp->cached--; + dirp->offset += ldir->d_reclen; + *result = entry; + return 0; + } + + /* Clear cached entries and reset offset */ + dirp->cached = 0; + dirp->offset = 0; + + ret = syscall(getdents64, dirp->fildes, dirp->buffer, + sizeof(dirp->buffer)); + if (ret < 0) + return errno; + + if (ret == 0) { + *result = NULL; + return 0; + } + + /* Read first entry from buffer. */ + nread = ret; + + /* Validate first entry bounds */ + if (nread < sizeof(struct linux_dirent64) || + ldir->d_reclen < offsetof(struct linux_dirent64, d_name) + 1 || + ldir->d_reclen > nread || ldir->d_reclen == 0) { + *result = NULL; + return EINVAL; + } + + dirp->offset = ldir->d_reclen; + entry->d_ino = ldir->d_ino; + + /* Calculate available space for name */ + size_t max_name_len = + ldir->d_reclen - offsetof(struct linux_dirent64, d_name); + if (max_name_len > sizeof(entry->d_name) - 1) { + max_name_len = sizeof(entry->d_name) - 1; + } + + /* Find actual string length, bounded by available space */ + size_t name_len = 0; + while (name_len < max_name_len && ldir->d_name[name_len] != '\0') { + name_len++; + } + + memcpy(entry->d_name, ldir->d_name, name_len); + entry->d_name[name_len] = '\0'; + *result = entry; + + /* Count the amount of remaining entries we have cached from getdents. + */ + for (ssize_t buffer_offset = ldir->d_reclen; buffer_offset < nread;) { + struct linux_dirent64 *next_ldir = + (void *)(dirp->buffer + buffer_offset); + + /* Validate entry bounds to prevent infinite loops */ + if (buffer_offset + sizeof(struct linux_dirent64) > nread || + next_ldir->d_reclen < + offsetof(struct linux_dirent64, d_name) + 1 || + buffer_offset + next_ldir->d_reclen > nread || + next_ldir->d_reclen == 0) { + break; + } + + buffer_offset += next_ldir->d_reclen; + dirp->cached++; + } + + return 0; +} -- cgit v1.2.3