Cleanup magiskboot cpio code

native/jni/magiskboot/cpio.cpp

@@ -0,0 +1,235 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <algorithm>
+
+#include <utils.hpp>
+
+#include "cpio.hpp"
+
+using namespace std;
+
+struct cpio_newc_header {
+    char magic[6];
+    char ino[8];
+    char mode[8];
+    char uid[8];
+    char gid[8];
+    char nlink[8];
+    char mtime[8];
+    char filesize[8];
+    char devmajor[8];
+    char devminor[8];
+    char rdevmajor[8];
+    char rdevminor[8];
+    char namesize[8];
+    char check[8];
+} __attribute__((packed));
+
+static uint32_t x8u(const char *hex) {
+    uint32_t val, inpos = 8, outpos;
+    char pattern[6];
+
+    while (*hex == '0') {
+        hex++;
+        if (!--inpos) return 0;
+    }
+    // Because scanf gratuitously treats %*X differently than printf does.
+    sprintf(pattern, "%%%dx%%n", inpos);
+    sscanf(hex, pattern, &val, &outpos);
+    if (inpos != outpos)
+        LOGE("bad cpio header\n");
+
+    return val;
+}
+
+cpio_entry::cpio_entry(uint32_t mode) : mode(mode), uid(0), gid(0), filesize(0), data(nullptr) {}
+
+cpio_entry::cpio_entry(const cpio_newc_header *h) :
+mode(x8u(h->mode)), uid(x8u(h->uid)), gid(x8u(h->gid)), filesize(x8u(h->filesize)), data(nullptr)
+{}
+
+void cpio::dump(const char *file) {
+    fprintf(stderr, "Dump cpio: [%s]\n", file);
+    dump(xfopen(file, "we"));
+}
+
+void cpio::rm(entry_map::iterator &it) {
+    fprintf(stderr, "Remove [%s]\n", it->first.data());
+    entries.erase(it);
+}
+
+void cpio::rm(const char *name, bool r) {
+    size_t len = strlen(name);
+    for (auto it = entries.begin(); it != entries.end();) {
+        if (it->first.compare(0, len, name) == 0 &&
+            ((r && it->first[len] == '/') || it->first[len] == '\0')) {
+            auto tmp = it;
+            ++it;
+            rm(tmp);
+            if (!r) return;
+        } else {
+            ++it;
+        }
+    }
+}
+
+void cpio::extract_entry(const entry_map::value_type &e, const char *file) {
+    fprintf(stderr, "Extract [%s] to [%s]\n", e.first.data(), file);
+    unlink(file);
+    rmdir(file);
+    if (S_ISDIR(e.second->mode)) {
+        ::mkdir(file, e.second->mode & 0777);
+    } else if (S_ISREG(e.second->mode)) {
+        int fd = creat(file, e.second->mode & 0777);
+        xwrite(fd, e.second->data, e.second->filesize);
+        fchown(fd, e.second->uid, e.second->gid);
+        close(fd);
+    } else if (S_ISLNK(e.second->mode)) {
+        auto target = strndup((char *) e.second->data, e.second->filesize);
+        symlink(target, file);
+        free(target);
+    }
+}
+
+void cpio::extract() {
+    for (auto &e : entries)
+        extract_entry(e, e.first.data());
+}
+
+bool cpio::extract(const char *name, const char *file) {
+    auto it = entries.find(name);
+    if (it != entries.end()) {
+        extract_entry(*it, file);
+        return true;
+    }
+    fprintf(stderr, "Cannot find the file entry [%s]\n", name);
+    return false;
+}
+
+bool cpio::exists(const char *name) {
+    return entries.count(name) != 0;
+}
+
+#define do_out(buf, len) pos += fwrite(buf, 1, len, out);
+#define out_align() do_out(zeros, align_off(pos, 4))
+void cpio::dump(FILE *out) {
+    size_t pos = 0;
+    unsigned inode = 300000;
+    char header[111];
+    char zeros[4] = {0};
+    for (auto &e : entries) {
+        sprintf(header, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x",
+                inode++,    // e->ino
+                e.second->mode,
+                e.second->uid,
+                e.second->gid,
+                1,          // e->nlink
+                0,          // e->mtime
+                e.second->filesize,
+                0,          // e->devmajor
+                0,          // e->devminor
+                0,          // e->rdevmajor
+                0,          // e->rdevminor
+                (uint32_t) e.first.size() + 1,
+                0           // e->check
+        );
+        do_out(header, 110);
+        do_out(e.first.data(), e.first.size() + 1);
+        out_align();
+        if (e.second->filesize) {
+            do_out(e.second->data, e.second->filesize);
+            out_align();
+        }
+    }
+    // Write trailer
+    sprintf(header, "070701%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x",
+            inode++, 0755, 0, 0, 1, 0, 0, 0, 0, 0, 0, 11, 0);
+    do_out(header, 110);
+    do_out("TRAILER!!!\0", 11);
+    out_align();
+    fclose(out);
+}
+
+void cpio::load_cpio(const char *file) {
+    char *buf;
+    size_t sz;
+    mmap_ro(file, buf, sz);
+    fprintf(stderr, "Loading cpio: [%s]\n", file);
+    load_cpio(buf, sz);
+    munmap(buf, sz);
+}
+
+void cpio::insert(string_view name, cpio_entry *e) {
+    auto it = entries.find(name);
+    if (it != entries.end()) {
+        it->second.reset(e);
+    } else {
+        entries.emplace(name, e);
+    }
+}
+
+void cpio::add(mode_t mode, const char *name, const char *file) {
+    void *buf;
+    size_t sz;
+    mmap_ro(file, buf, sz);
+    auto e = new cpio_entry(S_IFREG | mode);
+    e->filesize = sz;
+    e->data = xmalloc(sz);
+    memcpy(e->data, buf, sz);
+    munmap(buf, sz);
+    insert(name, e);
+    fprintf(stderr, "Add entry [%s] (%04o)\n", name, mode);
+}
+
+void cpio::mkdir(mode_t mode, const char *name) {
+    insert(name, new cpio_entry(S_IFDIR | mode));
+    fprintf(stderr, "Create directory [%s] (%04o)\n", name, mode);
+}
+
+void cpio::ln(const char *target, const char *name) {
+    auto e = new cpio_entry(S_IFLNK);
+    e->filesize = strlen(target);
+    e->data = strdup(target);
+    insert(name, e);
+    fprintf(stderr, "Create symlink [%s] -> [%s]\n", name, target);
+}
+
+void cpio::mv(entry_map::iterator &it, const char *name) {
+    fprintf(stderr, "Move [%s] -> [%s]\n", it->first.data(), name);
+    auto e = it->second.release();
+    entries.erase(it);
+    insert(name, e);
+}
+
+bool cpio::mv(const char *from, const char *to) {
+    auto it = entries.find(from);
+    if (it != entries.end()) {
+        mv(it, to);
+        return true;
+    }
+    fprintf(stderr, "Cannot find entry %s\n", from);
+    return false;
+}
+
+#define pos_align(p) p = do_align(p, 4)
+
+void cpio::load_cpio(const char *buf, size_t sz) {
+    size_t pos = 0;
+    while (pos < sz) {
+        auto header = reinterpret_cast<const cpio_newc_header *>(buf + pos);
+        pos += sizeof(cpio_newc_header);
+        string_view name(buf + pos);
+        pos += x8u(header->namesize);
+        pos_align(pos);
+        if (name == "." || name == "..")
+            continue;
+        if (name == "TRAILER!!!")
+            break;
+        auto entry = new cpio_entry(header);
+        entry->data = xmalloc(entry->filesize);
+        memcpy(entry->data, buf + pos, entry->filesize);
+        pos += entry->filesize;
+        insert(name, entry);
+        pos_align(pos);
+    }
+}

native/jni/magiskboot/cpio.hpp

@@ -0,0 +1,55 @@
+#pragma once
+
+#include <stdint.h>
+#include <string>
+#include <memory>
+#include <map>
+#include <string_view>
+
+struct cpio_newc_header;
+
+struct cpio_entry {
+    uint32_t mode;
+    uint32_t uid;
+    uint32_t gid;
+    uint32_t filesize;
+    void *data;
+
+    explicit cpio_entry(uint32_t mode = 0);
+    explicit cpio_entry(const cpio_newc_header *h);
+    ~cpio_entry() { free(data); }
+};
+
+class cpio {
+public:
+    struct StringCmp {
+        using is_transparent = void;
+        bool operator()(std::string_view a, std::string_view b) const {
+            return a < b;
+        }
+    };
+    using entry_map = std::map<std::string, std::unique_ptr<cpio_entry>, StringCmp>;
+
+    void load_cpio(const char *file);
+    void dump(const char *file);
+    void rm(const char *name, bool r = false);
+    void extract();
+    bool extract(const char *name, const char *file);
+    bool exists(const char *name);
+    void add(mode_t mode, const char *name, const char *file);
+    void mkdir(mode_t mode, const char *name);
+    void ln(const char *target, const char *name);
+    bool mv(const char *from, const char *to);
+
+protected:
+    entry_map entries;
+
+    static void extract_entry(const entry_map::value_type &e, const char *file);
+    void rm(entry_map::iterator &it);
+    void mv(entry_map::iterator &it, const char *name);
+
+private:
+    void dump(FILE *out);
+    void insert(std::string_view name, cpio_entry *e);
+    void load_cpio(const char *buf, size_t sz);
+};

native/jni/magiskboot/ramdisk.cpp

@@ -1,6 +1,6 @@
 #include <utils.hpp>
-#include <cpio.hpp>
 
+#include "cpio.hpp"
 #include "magiskboot.hpp"
 #include "compress.hpp"
 
@@ -14,9 +14,8 @@ static const char *MAGISK_LIST[] =
         { ".backup/.magisk", "init.magisk.rc",
           "overlay/init.magisk.rc" };
 
-class magisk_cpio : public cpio_rw {
+class magisk_cpio : public cpio {
 public:
-    using cpio_rw::cpio_rw;
     void patch();
     int test();
     char *sha1();
@@ -95,7 +94,7 @@ char *magisk_cpio::sha1() {
             }
         } else if (e.first == ".backup/.magisk") {
             for_each_line(line, e.second->data, e.second->filesize) {
-                if (strncmp(line, "SHA1=", 5) == 0) {
+                if (str_starts(line, "SHA1=")) {
                     strncpy(sha1, line + 5, 40);
                     sha1[40] = '\0';
                     return strdup(sha1);
@@ -114,15 +113,16 @@ for (str = (char *) buf; str < (char *) buf + size; str = str += strlen(str) + 1
 void magisk_cpio::restore() {
     if (auto it = entries.find(".backup/.rmlist"); it != entries.end()) {
         char *file;
-        for_each_str(file, it->second->data, it->second->filesize)
-            rm(file, false);
+        for_each_str(file, it->second->data, it->second->filesize) {
+            rm(file);
+        }
         rm(it);
     }
 
     for (auto it = entries.begin(); it != entries.end();) {
         auto cur = it++;
         if (str_starts(cur->first, ".backup")) {
-            if (cur->first.length() == 7 || cur->first.substr(8) == ".magisk") {
+            if (cur->first.length() == 7 || &cur->first[8] == ".magisk"sv) {
                 rm(cur);
             } else {
                 mv(cur, &cur->first[8]);
@@ -140,15 +140,15 @@ void magisk_cpio::restore() {
 void magisk_cpio::backup(const char *orig) {
     if (access(orig, R_OK))
         return;
-    entry_map bkup_entries;
-    string remv;
 
-    auto b = new cpio_entry(".backup", S_IFDIR);
-    bkup_entries[b->filename].reset(b);
+    entry_map backups;
+    string rm_list;
+    backups.emplace(".backup", new cpio_entry(S_IFDIR));
 
-    magisk_cpio o(orig);
+    magisk_cpio o;
+    o.load_cpio(orig);
 
-    // Remove possible backups in original ramdisk
+    // Remove existing backups in original ramdisk
     o.rm(".backup", true);
     rm(".backup", true);
 
@@ -157,7 +157,7 @@ void magisk_cpio::backup(const char *orig) {
 
     while (lhs != o.entries.end() || rhs != entries.end()) {
         int res;
-        bool backup = false;
+        bool do_backup = false;
         if (lhs != o.entries.end() && rhs != entries.end()) {
             res = lhs->first.compare(rhs->first);
         } else if (lhs == o.entries.end()) {
@@ -167,29 +167,28 @@ void magisk_cpio::backup(const char *orig) {
         }
 
         if (res < 0) {
-            // Something is missing in new ramdisk, backup!
-            backup = true;
+            // Something is missing in new ramdisk, do_backup!
+            do_backup = true;
             fprintf(stderr, "Backup missing entry: ");
         } else if (res == 0) {
             if (lhs->second->filesize != rhs->second->filesize ||
                 memcmp(lhs->second->data, rhs->second->data, lhs->second->filesize) != 0) {
                 // Not the same!
-                backup = true;
+                do_backup = true;
                 fprintf(stderr, "Backup mismatch entry: ");
             }
         } else {
             // Something new in ramdisk
-            remv += rhs->first;
-            remv += (char) '\0';
+            rm_list += rhs->first;
+            rm_list += (char) '\0';
             fprintf(stderr, "Record new entry: [%s] -> [.backup/.rmlist]\n", rhs->first.data());
         }
-        if (backup) {
-            string back_name(".backup/");
-            back_name += lhs->first;
-            fprintf(stderr, "[%s] -> [%s]\n", lhs->first.data(), back_name.data());
-            auto ex = static_cast<cpio_entry*>(lhs->second.release());
-            ex->filename = back_name;
-            bkup_entries[ex->filename].reset(ex);
+
+        if (do_backup) {
+            string name = ".backup/" + lhs->first;
+            fprintf(stderr, "[%s] -> [%s]\n", lhs->first.data(), name.data());
+            auto e = lhs->second.release();
+            backups.emplace(name, e);
         }
 
         // Increment positions
@@ -202,16 +201,16 @@ void magisk_cpio::backup(const char *orig) {
         }
     }
 
-    if (!remv.empty()) {
-        auto rmlist = new cpio_entry(".backup/.rmlist", S_IFREG);
-        rmlist->filesize = remv.length();
-        rmlist->data = xmalloc(remv.length());
-        memcpy(rmlist->data, remv.data(), remv.length());
-        bkup_entries[rmlist->filename].reset(rmlist);
+    if (!rm_list.empty()) {
+        auto rm_list_file = new cpio_entry(S_IFREG);
+        rm_list_file->filesize = rm_list.length();
+        rm_list_file->data = xmalloc(rm_list.length());
+        memcpy(rm_list_file->data, rm_list.data(), rm_list.length());
+        backups.emplace(".backup/.rmlist", rm_list_file);
     }
 
-    if (bkup_entries.size() > 1)
-        entries.merge(bkup_entries);
+    if (backups.size() > 1)
+        entries.merge(backups);
 }
 
 int cpio_commands(int argc, char *argv[]) {