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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-24 08:46:03 -0700
commitcf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch)
tree757a3d280760c654767631cab5ad8af2d86d1848 /fs/kernel_read_file.c
downloadlinux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz
linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ...
Diffstat (limited to 'fs/kernel_read_file.c')
-rw-r--r--fs/kernel_read_file.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
new file mode 100644
index 000000000..9c2ba9240
--- /dev/null
+++ b/fs/kernel_read_file.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/fs.h>
+#include <linux/fs_struct.h>
+#include <linux/kernel_read_file.h>
+#include <linux/security.h>
+#include <linux/vmalloc.h>
+
+/**
+ * kernel_read_file() - read file contents into a kernel buffer
+ *
+ * @file: file to read from
+ * @offset: where to start reading from (see below).
+ * @buf: pointer to a "void *" buffer for reading into (if
+ * *@buf is NULL, a buffer will be allocated, and
+ * @buf_size will be ignored)
+ * @buf_size: size of buf, if already allocated. If @buf not
+ * allocated, this is the largest size to allocate.
+ * @file_size: if non-NULL, the full size of @file will be
+ * written here.
+ * @id: the kernel_read_file_id identifying the type of
+ * file contents being read (for LSMs to examine)
+ *
+ * @offset must be 0 unless both @buf and @file_size are non-NULL
+ * (i.e. the caller must be expecting to read partial file contents
+ * via an already-allocated @buf, in at most @buf_size chunks, and
+ * will be able to determine when the entire file was read by
+ * checking @file_size). This isn't a recommended way to read a
+ * file, though, since it is possible that the contents might
+ * change between calls to kernel_read_file().
+ *
+ * Returns number of bytes read (no single read will be bigger
+ * than SSIZE_MAX), or negative on error.
+ *
+ */
+ssize_t kernel_read_file(struct file *file, loff_t offset, void **buf,
+ size_t buf_size, size_t *file_size,
+ enum kernel_read_file_id id)
+{
+ loff_t i_size, pos;
+ ssize_t copied;
+ void *allocated = NULL;
+ bool whole_file;
+ int ret;
+
+ if (offset != 0 && (!*buf || !file_size))
+ return -EINVAL;
+
+ if (!S_ISREG(file_inode(file)->i_mode))
+ return -EINVAL;
+
+ ret = deny_write_access(file);
+ if (ret)
+ return ret;
+
+ i_size = i_size_read(file_inode(file));
+ if (i_size <= 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+ /* The file is too big for sane activities. */
+ if (i_size > SSIZE_MAX) {
+ ret = -EFBIG;
+ goto out;
+ }
+ /* The entire file cannot be read in one buffer. */
+ if (!file_size && offset == 0 && i_size > buf_size) {
+ ret = -EFBIG;
+ goto out;
+ }
+
+ whole_file = (offset == 0 && i_size <= buf_size);
+ ret = security_kernel_read_file(file, id, whole_file);
+ if (ret)
+ goto out;
+
+ if (file_size)
+ *file_size = i_size;
+
+ if (!*buf)
+ *buf = allocated = vmalloc(i_size);
+ if (!*buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ pos = offset;
+ copied = 0;
+ while (copied < buf_size) {
+ ssize_t bytes;
+ size_t wanted = min_t(size_t, buf_size - copied,
+ i_size - pos);
+
+ bytes = kernel_read(file, *buf + copied, wanted, &pos);
+ if (bytes < 0) {
+ ret = bytes;
+ goto out_free;
+ }
+
+ if (bytes == 0)
+ break;
+ copied += bytes;
+ }
+
+ if (whole_file) {
+ if (pos != i_size) {
+ ret = -EIO;
+ goto out_free;
+ }
+
+ ret = security_kernel_post_read_file(file, *buf, i_size, id);
+ }
+
+out_free:
+ if (ret < 0) {
+ if (allocated) {
+ vfree(*buf);
+ *buf = NULL;
+ }
+ }
+
+out:
+ allow_write_access(file);
+ return ret == 0 ? copied : ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file);
+
+ssize_t kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
+ size_t buf_size, size_t *file_size,
+ enum kernel_read_file_id id)
+{
+ struct file *file;
+ ssize_t ret;
+
+ if (!path || !*path)
+ return -EINVAL;
+
+ file = filp_open(path, O_RDONLY, 0);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
+ fput(file);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
+
+ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset,
+ void **buf, size_t buf_size,
+ size_t *file_size,
+ enum kernel_read_file_id id)
+{
+ struct file *file;
+ ssize_t ret;
+
+ if (!path || !*path)
+ return -EINVAL;
+
+ scoped_with_init_fs()
+ file = filp_open(path, O_RDONLY, 0);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ ret = kernel_read_file(file, offset, buf, buf_size, file_size, id);
+ fput(file);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
+
+ssize_t kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
+ size_t buf_size, size_t *file_size,
+ enum kernel_read_file_id id)
+{
+ CLASS(fd, f)(fd);
+
+ if (fd_empty(f) || !(fd_file(f)->f_mode & FMODE_READ))
+ return -EBADF;
+
+ return kernel_read_file(fd_file(f), offset, buf, buf_size, file_size, id);
+}
+EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);