Switch mkbootfs to C++.

Minimum changes just to get it to compile as C++, no real cleanup.

Change-Id: I8ff3fa35a07cdc9a6a246e79e33581e5d6598833
diff --git a/mkbootfs/mkbootfs.cpp b/mkbootfs/mkbootfs.cpp
new file mode 100644
index 0000000..65cf497
--- /dev/null
+++ b/mkbootfs/mkbootfs.cpp
@@ -0,0 +1,462 @@
+
+#include <ctype.h>
+#include <dirent.h>
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <linux/kdev_t.h>
+
+#include <private/android_filesystem_config.h>
+#include <private/fs_config.h>
+
+/* NOTES
+**
+** - see https://www.kernel.org/doc/Documentation/early-userspace/buffer-format.txt
+**   for an explanation of this file format
+** - dotfiles are ignored
+** - directories named 'root' are ignored
+*/
+
+struct fs_config_entry {
+    char* name;
+    int uid, gid, mode;
+};
+
+static struct fs_config_entry* canned_config = NULL;
+static const char* target_out_path = NULL;
+
+#define TRAILER "TRAILER!!!"
+
+static int total_size = 0;
+
+static void fix_stat(const char *path, struct stat *s)
+{
+    uint64_t capabilities;
+    if (canned_config) {
+        // Use the list of file uid/gid/modes loaded from the file
+        // given with -f.
+
+        struct fs_config_entry* empty_path_config = NULL;
+        struct fs_config_entry* p;
+        for (p = canned_config; p->name; ++p) {
+            if (!p->name[0]) {
+                empty_path_config = p;
+            }
+            if (strcmp(p->name, path) == 0) {
+                s->st_uid = p->uid;
+                s->st_gid = p->gid;
+                s->st_mode = p->mode | (s->st_mode & ~07777);
+                return;
+            }
+        }
+        s->st_uid = empty_path_config->uid;
+        s->st_gid = empty_path_config->gid;
+        s->st_mode = empty_path_config->mode | (s->st_mode & ~07777);
+    } else {
+        // Use the compiled-in fs_config() function.
+        unsigned st_mode = s->st_mode;
+        int is_dir = S_ISDIR(s->st_mode) || strcmp(path, TRAILER) == 0;
+        fs_config(path, is_dir, target_out_path, &s->st_uid, &s->st_gid, &st_mode, &capabilities);
+        s->st_mode = (typeof(s->st_mode)) st_mode;
+    }
+
+    if (S_ISREG(s->st_mode) || S_ISDIR(s->st_mode) || S_ISLNK(s->st_mode)) {
+        s->st_rdev = 0;
+    }
+}
+
+static void _eject(struct stat *s, const char *out, int olen, char *data, unsigned datasize)
+{
+    // Nothing is special about this value, just picked something in the
+    // approximate range that was being used already, and avoiding small
+    // values which may be special.
+    static unsigned next_inode = 300000;
+
+    while(total_size & 3) {
+        total_size++;
+        putchar(0);
+    }
+
+    fix_stat(out, s);
+//    fprintf(stderr, "_eject %s: mode=0%o\n", out, s->st_mode);
+
+    printf("%06x%08x%08x%08x%08x%08x%08x"
+           "%08x%08x%08x%08x%08x%08x%08x%s%c",
+           0x070701,
+           next_inode++,  //  s.st_ino,
+           s->st_mode,
+           0, // s.st_uid,
+           0, // s.st_gid,
+           1, // s.st_nlink,
+           0, // s.st_mtime,
+           datasize,
+           0, // volmajor
+           0, // volminor
+           major(s->st_rdev),
+           minor(s->st_rdev),
+           olen + 1,
+           0,
+           out,
+           0
+           );
+
+    total_size += 6 + 8*13 + olen + 1;
+
+    if(strlen(out) != (unsigned int)olen) errx(1, "ACK!");
+
+    while(total_size & 3) {
+        total_size++;
+        putchar(0);
+    }
+
+    if(datasize) {
+        fwrite(data, datasize, 1, stdout);
+        total_size += datasize;
+    }
+}
+
+static void _eject_trailer()
+{
+    struct stat s;
+    memset(&s, 0, sizeof(s));
+    _eject(&s, TRAILER, 10, 0, 0);
+
+    while(total_size & 0xff) {
+        total_size++;
+        putchar(0);
+    }
+}
+
+static void _archive(char *in, char *out, int ilen, int olen);
+
+static int compare(const void* a, const void* b) {
+  return strcmp(*(const char**)a, *(const char**)b);
+}
+
+static void _archive_dir(char *in, char *out, int ilen, int olen)
+{
+    int i, t;
+    struct dirent *de;
+
+    DIR* d = opendir(in);
+    if (d == NULL) err(1, "cannot open directory '%s'", in);
+
+    // TODO: switch to std::vector
+    int size = 32;
+    int entries = 0;
+    char** names = (char**) malloc(size * sizeof(char*));
+    if (names == NULL) {
+      errx(1, "failed to allocate dir names array (size %d)", size);
+    }
+
+    while((de = readdir(d)) != 0){
+            /* xxx: feature? maybe some dotfiles are okay */
+        if(de->d_name[0] == '.') continue;
+
+            /* xxx: hack. use a real exclude list */
+        if(!strcmp(de->d_name, "root")) continue;
+
+        if (entries >= size) {
+          size *= 2;
+          names = (char**) realloc(names, size * sizeof(char*));
+          if (names == NULL) {
+            errx(1, "failed to reallocate dir names array (size %d)", size);
+          }
+        }
+        names[entries] = strdup(de->d_name);
+        if (names[entries] == NULL) {
+          errx(1, "failed to strdup name \"%s\"", de->d_name);
+        }
+        ++entries;
+    }
+
+    qsort(names, entries, sizeof(char*), compare);
+
+    for (i = 0; i < entries; ++i) {
+        t = strlen(names[i]);
+        in[ilen] = '/';
+        memcpy(in + ilen + 1, names[i], t + 1);
+
+        if(olen > 0) {
+            out[olen] = '/';
+            memcpy(out + olen + 1, names[i], t + 1);
+            _archive(in, out, ilen + t + 1, olen + t + 1);
+        } else {
+            memcpy(out, names[i], t + 1);
+            _archive(in, out, ilen + t + 1, t);
+        }
+
+        in[ilen] = 0;
+        out[olen] = 0;
+
+        free(names[i]);
+    }
+    free(names);
+
+    closedir(d);
+}
+
+static void _archive(char *in, char *out, int ilen, int olen)
+{
+    struct stat s;
+    if(lstat(in, &s)) err(1, "could not stat '%s'", in);
+
+    if(S_ISREG(s.st_mode)){
+        int fd = open(in, O_RDONLY);
+        if(fd < 0) err(1, "cannot open '%s' for read", in);
+
+        char* tmp = (char*) malloc(s.st_size);
+        if(tmp == 0) errx(1, "cannot allocate %zd bytes", s.st_size);
+
+        if(read(fd, tmp, s.st_size) != s.st_size) {
+            err(1, "cannot read %zd bytes", s.st_size);
+        }
+
+        _eject(&s, out, olen, tmp, s.st_size);
+
+        free(tmp);
+        close(fd);
+    } else if(S_ISDIR(s.st_mode)) {
+        _eject(&s, out, olen, 0, 0);
+        _archive_dir(in, out, ilen, olen);
+    } else if(S_ISLNK(s.st_mode)) {
+        char buf[1024];
+        int size;
+        size = readlink(in, buf, 1024);
+        if(size < 0) err(1, "cannot read symlink '%s'", in);
+        _eject(&s, out, olen, buf, size);
+    } else if(S_ISBLK(s.st_mode) || S_ISCHR(s.st_mode) ||
+              S_ISFIFO(s.st_mode) || S_ISSOCK(s.st_mode)) {
+        _eject(&s, out, olen, NULL, 0);
+    } else {
+        errx(1, "Unknown '%s' (mode %d)?", in, s.st_mode);
+    }
+}
+
+static void archive(const char* start, const char* prefix) {
+    char in[8192];
+    char out[8192];
+
+    strcpy(in, start);
+    strcpy(out, prefix);
+
+    _archive_dir(in, out, strlen(in), strlen(out));
+}
+
+static void read_canned_config(char* filename)
+{
+    int allocated = 8;
+    int used = 0;
+
+    canned_config =
+        (struct fs_config_entry*)malloc(allocated * sizeof(struct fs_config_entry));
+
+    FILE* fp = fopen(filename, "r");
+    if (fp == NULL) err(1, "failed to open canned file '%s'", filename);
+
+    char* line = NULL;
+    size_t allocated_len;
+    while (getline(&line, &allocated_len, fp) != -1) {
+        if (!line[0]) break;
+        if (used >= allocated) {
+            allocated *= 2;
+            canned_config = (struct fs_config_entry*)realloc(
+                canned_config, allocated * sizeof(struct fs_config_entry));
+            if (canned_config == NULL) errx(1, "failed to reallocate memory");
+        }
+
+        struct fs_config_entry* cc = canned_config + used;
+
+        if (isspace(line[0])) {
+            cc->name = strdup("");
+            cc->uid = atoi(strtok(line, " \n"));
+        } else {
+            cc->name = strdup(strtok(line, " \n"));
+            cc->uid = atoi(strtok(NULL, " \n"));
+        }
+        cc->gid = atoi(strtok(NULL, " \n"));
+        cc->mode = strtol(strtok(NULL, " \n"), NULL, 8);
+        ++used;
+    }
+    if (used >= allocated) {
+        ++allocated;
+        canned_config = (struct fs_config_entry*)realloc(
+            canned_config, allocated * sizeof(struct fs_config_entry));
+        if (canned_config == NULL) errx(1, "failed to reallocate memory");
+    }
+    canned_config[used].name = NULL;
+
+    free(line);
+    fclose(fp);
+}
+
+static void devnodes_desc_error(const char* filename, unsigned long line_num,
+                              const char* msg)
+{
+    errx(1, "failed to read nodes desc file '%s' line %lu: %s", filename, line_num, msg);
+}
+
+static int append_devnodes_desc_dir(char* path, char* args)
+{
+    struct stat s;
+
+    if (sscanf(args, "%o %d %d", &s.st_mode, &s.st_uid, &s.st_gid) != 3) return -1;
+
+    s.st_mode |= S_IFDIR;
+
+    _eject(&s, path, strlen(path), NULL, 0);
+
+    return 0;
+}
+
+static int append_devnodes_desc_nod(char* path, char* args)
+{
+    int minor, major;
+    struct stat s;
+    char dev;
+
+    if (sscanf(args, "%o %d %d %c %d %d", &s.st_mode, &s.st_uid, &s.st_gid,
+               &dev, &major, &minor) != 6) return -1;
+
+    s.st_rdev = MKDEV(major, minor);
+    switch (dev) {
+    case 'b':
+        s.st_mode |= S_IFBLK;
+        break;
+    case 'c':
+        s.st_mode |= S_IFCHR;
+        break;
+    default:
+        return -1;
+    }
+
+    _eject(&s, path, strlen(path), NULL, 0);
+
+    return 0;
+}
+
+static void append_devnodes_desc(const char* filename)
+{
+    FILE* fp = fopen(filename, "re");
+    if (!fp) err(1, "failed to open nodes description file '%s'", filename);
+
+    unsigned long line_num = 0;
+
+    char* line = NULL;
+    size_t allocated_len;
+    while (getline(&line, &allocated_len, fp) != -1) {
+        char *type, *path, *args;
+
+        line_num++;
+
+        if (*line == '#') continue;
+
+        if (!(type = strtok(line, " \t"))) {
+            devnodes_desc_error(filename, line_num, "a type is missing");
+        }
+
+        if (*type == '\n') continue;
+
+        if (!(path = strtok(NULL, " \t"))) {
+            devnodes_desc_error(filename, line_num, "a path is missing");
+        }
+
+        if (!(args = strtok(NULL, "\n"))) {
+            devnodes_desc_error(filename, line_num, "args are missing");
+        }
+
+        if (!strcmp(type, "dir")) {
+            if (append_devnodes_desc_dir(path, args)) {
+                devnodes_desc_error(filename, line_num, "bad arguments for dir");
+            }
+        } else if (!strcmp(type, "nod")) {
+            if (append_devnodes_desc_nod(path, args)) {
+                devnodes_desc_error(filename, line_num, "bad arguments for nod");
+            }
+        } else {
+            devnodes_desc_error(filename, line_num, "type unknown");
+        }
+    }
+
+    free(line);
+    fclose(fp);
+}
+
+static const struct option long_options[] = {
+    { "dirname",    required_argument,  NULL,   'd' },
+    { "file",       required_argument,  NULL,   'f' },
+    { "help",       no_argument,        NULL,   'h' },
+    { "nodes",      required_argument,  NULL,   'n' },
+    { NULL,         0,                  NULL,   0   },
+};
+
+static void usage(void)
+{
+    fprintf(stderr,
+            "Usage: mkbootfs [-n FILE] [-d DIR|-f FILE] DIR...\n"
+            "\n"
+            "\t-d, --dirname=DIR: fs-config directory\n"
+            "\t-f, --file=FILE: Canned configuration file\n"
+            "\t-h, --help: Print this help\n"
+            "\t-n, --nodes=FILE: Dev nodes description file\n"
+            "\n"
+            "Dev nodes description:\n"
+            "\t[dir|nod] [perms] [uid] [gid] [c|b] [major] [minor]\n"
+            "\tExample:\n"
+            "\t\t# My device nodes\n"
+            "\t\tdir dev 0755 0 0\n"
+            "\t\tnod dev/null 0600 0 0 c 1 3\n"
+    );
+}
+
+int main(int argc, char *argv[])
+{
+    int opt, unused;
+
+    while ((opt = getopt_long(argc, argv, "hd:f:n:", long_options, &unused)) != -1) {
+        switch (opt) {
+        case 'd':
+            target_out_path = argv[optind - 1];
+            break;
+        case 'f':
+            read_canned_config(argv[optind - 1]);
+            break;
+        case 'h':
+            usage();
+            return 0;
+        case 'n':
+            append_devnodes_desc(argv[optind - 1]);
+            break;
+        default:
+            usage();
+            errx(1, "Unknown option %s", argv[optind - 1]);
+        }
+    }
+
+    int num_dirs = argc - optind;
+    argv += optind;
+
+    while (num_dirs-- > 0){
+        char *x = strchr(*argv, '=');
+        if (x != nullptr) {
+            *x++ = '\0';
+        }
+        archive(*argv, x ?: "");
+
+        argv++;
+    }
+
+    _eject_trailer();
+
+    return 0;
+}