recovery: Fork a process for fuse when sideloading from SD card. (cdcf28f5) · Commits · e / tools / etwrp

fuse_sdcard_provider.cpp

+11 −63

Original line number	Diff line number	Diff line
		@@ -18,7 +18,6 @@
		#include <stdio.h>
		#include <string.h>
		#include <errno.h>
		#include <pthread.h>
		#include <sys/mount.h>
		#include <sys/stat.h>
		#include <unistd.h>
		@@ -60,81 +59,30 @@ static void close_file(void* cookie) {
		close(fd->fd);
		}

		struct token {
		pthread_t th;
		const char* path;
		int result;
		};

		static void* run_sdcard_fuse(void* cookie) {
		token* t = reinterpret_cast<token*>(cookie);

		bool start_sdcard_fuse(const char* path) {
		struct stat sb;
		if (stat(t->path, &sb) < 0) {
		fprintf(stderr, "failed to stat %s: %s\n", t->path, strerror(errno));
		t->result = -1;
		return NULL;
		if (stat(path, &sb) == -1) {
		fprintf(stderr, "failed to stat %s: %s\n", path, strerror(errno));
		return false;
		}

		struct file_data fd;
		struct provider_vtab vtab;

		fd.fd = open(t->path, O_RDONLY);
		if (fd.fd < 0) {
		fprintf(stderr, "failed to open %s: %s\n", t->path, strerror(errno));
		t->result = -1;
		return NULL;
		file_data fd;
		fd.fd = open(path, O_RDONLY);
		if (fd.fd == -1) {
		fprintf(stderr, "failed to open %s: %s\n", path, strerror(errno));
		return false;
		}
		fd.file_size = sb.st_size;
		fd.block_size = 65536;

		provider_vtab vtab;
		vtab.read_block = read_block_file;
		vtab.close = close_file;

		t->result = run_fuse_sideload(&vtab, &fd, fd.file_size, fd.block_size);
		return NULL;
		}

		// How long (in seconds) we wait for the fuse-provided package file to
		// appear, before timing out.
		#define SDCARD_INSTALL_TIMEOUT 10

		void* start_sdcard_fuse(const char* path) {
		token* t = new token;

		t->path = path;
		pthread_create(&(t->th), NULL, run_sdcard_fuse, t);

		struct stat st;
		int i;
		for (i = 0; i < SDCARD_INSTALL_TIMEOUT; ++i) {
		if (stat(FUSE_SIDELOAD_HOST_PATHNAME, &st) != 0) {
		if (errno == ENOENT && i < SDCARD_INSTALL_TIMEOUT-1) {
		sleep(1);
		continue;
		} else {
		return NULL;
		}
		}
		}

		// The installation process expects to find the sdcard unmounted.
		// Unmount it with MNT_DETACH so that our open file continues to
		// work but new references see it as unmounted.
		umount2("/sdcard", MNT_DETACH);

		return t;
		}

		void finish_sdcard_fuse(void* cookie) {
		if (cookie == NULL) return;
		token* t = reinterpret_cast<token*>(cookie);

		// Calling stat() on this magic filename signals the fuse
		// filesystem to shut down.
		struct stat st;
		stat(FUSE_SIDELOAD_HOST_EXIT_PATHNAME, &st);

		pthread_join(t->th, NULL);
		delete t;
		return run_fuse_sideload(&vtab, &fd, fd.file_size, fd.block_size) == 0;
		}

fuse_sdcard_provider.h

+1 −2

Original line number	Diff line number	Diff line
		@@ -17,7 +17,6 @@
		#ifndef __FUSE_SDCARD_PROVIDER_H
		#define __FUSE_SDCARD_PROVIDER_H

		void* start_sdcard_fuse(const char* path);
		void finish_sdcard_fuse(void* token);
		bool start_sdcard_fuse(const char* path);

		#endif

recovery.cpp

+57 −4

Original line number	Diff line number	Diff line
		@@ -28,6 +28,7 @@
		#include <sys/klog.h>
		#include <sys/stat.h>
		#include <sys/types.h>
		#include <sys/wait.h>
		#include <time.h>
		#include <unistd.h>

		@@ -833,6 +834,10 @@ static void choose_recovery_file(Device* device) {
		}
		}

		// How long (in seconds) we wait for the fuse-provided package file to
		// appear, before timing out.
		#define SDCARD_INSTALL_TIMEOUT 10

		static int apply_from_sdcard(Device* device, bool* wipe_cache) {
		modified_flash = true;

		@@ -850,14 +855,62 @@ static int apply_from_sdcard(Device* device, bool* wipe_cache) {

		ui->Print("\n-- Install %s ...\n", path);
		set_sdcard_update_bootloader_message();
		void* token = start_sdcard_fuse(path);

		int status = install_package(FUSE_SIDELOAD_HOST_PATHNAME, wipe_cache,
		// We used to use fuse in a thread as opposed to a process. Since accessing
		// through fuse involves going from kernel to userspace to kernel, it leads
		// to deadlock when a page fault occurs. (Bug: 26313124)
		pid_t child;
		if ((child = fork()) == 0) {
		bool status = start_sdcard_fuse(path);

		_exit(status ? EXIT_SUCCESS : EXIT_FAILURE);
		}

		// FUSE_SIDELOAD_HOST_PATHNAME will start to exist once the fuse in child
		// process is ready.
		int result = INSTALL_ERROR;
		int status;
		bool waited = false;
		for (int i = 0; i < SDCARD_INSTALL_TIMEOUT; ++i) {
		if (waitpid(child, &status, WNOHANG) == -1) {
		result = INSTALL_ERROR;
		waited = true;
		break;
		}

		struct stat sb;
		if (stat(FUSE_SIDELOAD_HOST_PATHNAME, &sb) == -1) {
		if (errno == ENOENT && i < SDCARD_INSTALL_TIMEOUT-1) {
		sleep(1);
		continue;
		} else {
		LOGE("Timed out waiting for the fuse-provided package.\n");
		result = INSTALL_ERROR;
		kill(child, SIGKILL);
		break;
		}
		}

		result = install_package(FUSE_SIDELOAD_HOST_PATHNAME, wipe_cache,
		TEMPORARY_INSTALL_FILE, false);
		break;
		}

		if (!waited) {
		// Calling stat() on this magic filename signals the fuse
		// filesystem to shut down.
		struct stat sb;
		stat(FUSE_SIDELOAD_HOST_EXIT_PATHNAME, &sb);

		waitpid(child, &status, 0);
		}

		if (!WIFEXITED(status) \|\| WEXITSTATUS(status) != 0) {
		LOGE("Error exit from the fuse process: %d\n", WEXITSTATUS(status));
		}

		finish_sdcard_fuse(token);
		ensure_path_unmounted(SDCARD_ROOT);
		return status;
		return result;
		}

		// Return REBOOT, SHUTDOWN, or REBOOT_BOOTLOADER. Returning NO_ACTION