diff options
Diffstat (limited to 'appliance/libguestfs-supermin-helper.c')
| -rw-r--r-- | appliance/libguestfs-supermin-helper.c | 919 |
1 files changed, 0 insertions, 919 deletions
diff --git a/appliance/libguestfs-supermin-helper.c b/appliance/libguestfs-supermin-helper.c deleted file mode 100644 index 127b5c0e..00000000 --- a/appliance/libguestfs-supermin-helper.c +++ /dev/null @@ -1,919 +0,0 @@ -/* libguestfs-supermin-helper reimplementation in C. - * Copyright (C) 2009-2010 Red Hat Inc. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - */ - -/* This script builds the supermin appliance on the fly each - * time the appliance runs. - * - * *NOTE*: This program is designed to be very short-lived, and so we - * don't normally bother to free up any memory that we allocate. - * That's not completely true - we free up stuff if it's obvious and - * easy to free up, and ignore the rest. - */ - -#include <config.h> - -#include <stdio.h> -#include <stdlib.h> -#include <stdarg.h> -#include <stdint.h> -#include <string.h> -#include <errno.h> -#include <fcntl.h> -#include <inttypes.h> -#include <unistd.h> -#include <getopt.h> -#include <limits.h> -#include <fnmatch.h> -#include <dirent.h> -#include <sys/types.h> -#include <sys/time.h> -#include <sys/stat.h> -#include <assert.h> - -#include "error.h" -#include "filevercmp.h" -#include "fts_.h" -#include "full-write.h" -#include "hash.h" -#include "hash-pjw.h" -#include "xalloc.h" -#include "xvasprintf.h" - -/* Directory containing candidate kernels. We could make this - * configurable at some point. - */ -#define KERNELDIR "/boot" -#define MODULESDIR "/lib/modules" - -/* Buffer size used in copy operations throughout. Large for - * greatest efficiency. - */ -#define BUFFER_SIZE 65536 - -static struct timeval start_t; -static int verbose = 0; - -static void print_timestamped_message (const char *fs, ...); -static const char *create_kernel (const char *hostcpu, const char *kernel); -static void create_appliance (const char *sourcedir, const char *hostcpu, const char *repo, const char *modpath, const char *initrd); - -enum { HELP_OPTION = CHAR_MAX + 1 }; - -static const char *options = "vV"; -static const struct option long_options[] = { - { "help", 0, 0, HELP_OPTION }, - { "verbose", 0, 0, 'v' }, - { "version", 0, 0, 'V' }, - { 0, 0, 0, 0 } -}; - -static void -usage (const char *progname) -{ - printf ("%s: build the supermin appliance on the fly\n" - "\n" - "Usage:\n" - " %s [-options] sourcedir host_cpu repo kernel initrd\n" - " %s --help\n" - " %s --version\n" - "\n" - "This script is used by libguestfs to build the supermin appliance\n" - "(kernel and initrd output files). You should NOT need to run this\n" - "program directly except if you are debugging tricky supermin\n" - "appliance problems.\n" - "\n" - "NB: The kernel and initrd parameters are OUTPUT parameters. If\n" - "those files exist, they are overwritten by the output.\n" - "\n" - "Options:\n" - " --help\n" - " Display this help text and exit.\n" - " --verbose | -v\n" - " Enable verbose messages (give multiple times for more verbosity).\n" - " --version | -V\n" - " Display version number and exit.\n" - "\n" - "Typical usage when debugging supermin appliance problems:\n" - " %s -v /usr/lib*/guestfs x86_64 fedora-12 /tmp/kernel /tmp/initrd\n" - "Note: This will OVERWRITE any existing files called /tmp/kernel\n" - "and /tmp/initrd.\n", - progname, progname, progname, progname, progname); -} - -int -main (int argc, char *argv[]) -{ - /* First thing: start the clock. */ - gettimeofday (&start_t, NULL); - - /* Command line arguments. */ - for (;;) { - int c = getopt_long (argc, argv, options, long_options, NULL); - if (c == -1) break; - - switch (c) { - case HELP_OPTION: - usage (argv[0]); - exit (EXIT_SUCCESS); - - case 'v': - verbose++; - break; - - case 'V': - printf (PACKAGE_NAME " " PACKAGE_VERSION "\n"); - exit (EXIT_SUCCESS); - - default: - usage (argv[0]); - exit (EXIT_FAILURE); - } - } - - if (argc - optind != 5) { - usage (argv[0]); - exit (EXIT_FAILURE); - } - - const char *sourcedir = argv[optind]; - - /* Host CPU and repo constants passed from the library (see: - * https://bugzilla.redhat.com/show_bug.cgi?id=558593). - */ - const char *hostcpu = argv[optind+1]; - const char *repo = argv[optind+2]; - - /* Output files. */ - const char *kernel = argv[optind+3]; - const char *initrd = argv[optind+4]; - - if (verbose) - print_timestamped_message ("sourcedir = %s, " - "host_cpu = %s, " - "repo = %s, " - "kernel = %s, " - "initrd = %s", - sourcedir, hostcpu, repo, kernel, initrd); - - /* Remove the output files if they exist. */ - unlink (kernel); - unlink (initrd); - - /* Create kernel output file. */ - const char *modpath; - modpath = create_kernel (hostcpu, kernel); - - if (verbose) - print_timestamped_message ("finished creating kernel"); - - /* Create the appliance. */ - create_appliance (sourcedir, hostcpu, repo, modpath, initrd); - - if (verbose) - print_timestamped_message ("finished creating appliance"); - - exit (EXIT_SUCCESS); -} - -/* Compute Y - X and return the result in milliseconds. - * Approximately the same as this code: - * http://www.mpp.mpg.de/~huber/util/timevaldiff.c - */ -static int64_t -timeval_diff (const struct timeval *x, const struct timeval *y) -{ - int64_t msec; - - msec = (y->tv_sec - x->tv_sec) * 1000; - msec += (y->tv_usec - x->tv_usec) / 1000; - return msec; -} - -static void -print_timestamped_message (const char *fs, ...) -{ - struct timeval tv; - gettimeofday (&tv, NULL); - - va_list args; - char *msg; - int err; - - va_start (args, fs); - err = vasprintf (&msg, fs, args); - va_end (args); - - if (err < 0) return; - - fprintf (stderr, "supermin helper [%05" PRIi64 "ms] %s\n", - timeval_diff (&start_t, &tv), msg); - - free (msg); -} - -static char **read_dir (const char *dir); -static char **filter_fnmatch (char **strings, const char *patt, int flags); -static char **filter_notmatching_substring (char **strings, const char *sub); -static void sort (char **strings, int (*compare) (const void *, const void *)); -static int isdir (const char *path); - -static int -reverse_filevercmp (const void *p1, const void *p2) -{ - const char *s1 = * (char * const *) p1; - const char *s2 = * (char * const *) p2; - - /* Note, arguments are reversed to achieve a reverse sort. */ - return filevercmp (s2, s1); -} - -/* Create the kernel. This chooses an appropriate kernel and makes a - * symlink to it. - * - * Look for the most recent kernel named vmlinuz-*.<arch>* which has a - * corresponding directory in /lib/modules/. If the architecture is - * x86, look for any x86 kernel. - * - * RHEL 5 didn't append the arch to the kernel name, so look for - * kernels without arch second. - * - * If no suitable kernel can be found, exit with an error. - * - * This function returns the module path (ie. /lib/modules/<version>). - */ -static const char * -create_kernel (const char *hostcpu, const char *kernel) -{ - char **all_files = read_dir (KERNELDIR); - - /* In original: ls -1dvr /boot/vmlinuz-*.$arch* 2>/dev/null | grep -v xen */ - const char *patt; - if (hostcpu[0] == 'i' && hostcpu[2] == '8' && hostcpu[3] == '6' && - hostcpu[4] == '\0') - patt = "vmlinuz-*.i?86*"; - else - patt = xasprintf ("vmlinuz-*.%s*", hostcpu); - - char **candidates; - candidates = filter_fnmatch (all_files, patt, FNM_NOESCAPE); - candidates = filter_notmatching_substring (candidates, "xen"); - - if (candidates[0] == NULL) { - /* In original: ls -1dvr /boot/vmlinuz-* 2>/dev/null | grep -v xen */ - patt = "vmlinuz-*"; - candidates = filter_fnmatch (all_files, patt, FNM_NOESCAPE); - candidates = filter_notmatching_substring (candidates, "xen"); - - if (candidates[0] == NULL) - goto no_kernels; - } - - sort (candidates, reverse_filevercmp); - - /* Choose the first candidate which has a corresponding /lib/modules - * directory. - */ - int i; - for (i = 0; candidates[i] != NULL; ++i) { - if (verbose >= 2) - fprintf (stderr, "candidate kernel: " KERNELDIR "/%s\n", candidates[i]); - - /* Ignore "vmlinuz-" at the beginning of the kernel name. */ - const char *version = &candidates[i][8]; - - /* /lib/modules/<version> */ - char *modpath = xasprintf (MODULESDIR "/%s", version); - - if (verbose >= 2) - fprintf (stderr, "checking modpath %s is a directory\n", modpath); - - if (isdir (modpath)) { - if (verbose >= 2) - fprintf (stderr, "picked %s because modpath %s exists\n", - candidates[i], modpath); - - char *tmp = xasprintf (KERNELDIR "/%s", candidates[i]); - - if (verbose >= 2) - fprintf (stderr, "creating symlink %s -> %s\n", kernel, tmp); - - if (symlink (tmp, kernel) == -1) - error (EXIT_FAILURE, errno, "symlink kernel"); - - free (tmp); - - return modpath; - } - } - - /* Print more diagnostics here than the old script did. */ - no_kernels: - fprintf (stderr, - "libguestfs-supermin-helper: failed to find a suitable kernel.\n" - "I looked for kernels in " KERNELDIR " and modules in " MODULESDIR - ".\n" - "If this is a Xen guest, and you only have Xen domU kernels\n" - "installed, try installing a fullvirt kernel (only for\n" - "libguestfs use, you shouldn't boot the Xen guest with it).\n"); - exit (EXIT_FAILURE); -} - -static void write_kernel_modules (const char *sourcedir, const char *modpath); -static void write_hostfiles (const char *sourcedir, const char *hostcpu, const char *repo); -static void write_to_fd (const void *buffer, size_t len); -static void write_file_to_fd (const char *filename); -static void write_file_len_to_fd (const char *filename, size_t len); -static void write_padding (size_t len); -static char **load_file (const char *filename); -static void cpio_append_fts_entry (FTSENT *entry); -static void cpio_append_stat (const char *filename, struct stat *); -static void cpio_append (const char *filename); -static void cpio_append_trailer (void); - -static int out_fd = -1; -static off_t out_offset = 0; - -/* Create the appliance. - * - * The initrd consists of these components concatenated together: - * - * (1) The base skeleton appliance that we constructed at build time. - * name = initramfs.$repo.$host_cpu.supermin.img - * format = plain cpio - * (2) The modules from modpath which are on the module whitelist. - * format = plain cpio - * (3) The host files which match wildcards in *.supermin.hostfiles. - * format = plain cpio - * - * The original shell scripted used the external cpio program to - * create parts (2) and (3), but we have decided it's going to be - * faster if we just write out the data outselves. The reasons are - * that external cpio is slow (particularly when used with SELinux - * because it does 512 byte reads), and the format that we're writing - * is narrow and well understood, because we only care that the Linux - * kernel can read it. - */ -static void -create_appliance (const char *sourcedir, - const char *hostcpu, const char *repo, - const char *modpath, - const char *initrd) -{ - out_fd = open (initrd, O_WRONLY | O_CREAT | O_TRUNC | O_NOCTTY, 0644); - if (out_fd == -1) - error (EXIT_FAILURE, errno, "open: %s", initrd); - out_offset = 0; - - /* Copy the base skeleton appliance (1). */ - char *tmp = xasprintf ("%s/initramfs.%s.%s.supermin.img", - sourcedir, repo, hostcpu); - write_file_to_fd (tmp); - free (tmp); - - /* Kernel modules (2). */ - write_kernel_modules (sourcedir, modpath); - - /* Copy hostfiles (3). */ - write_hostfiles (sourcedir, hostcpu, repo); - - cpio_append_trailer (); - - /* Finish off and close output file. */ - if (close (out_fd) == -1) - error (EXIT_FAILURE, errno, "close: %s", initrd); -} - -/* Copy kernel modules. - * - * Find every file under modpath. - * - * Exclude all *.ko files, *except* ones which match names in - * the whitelist (which may contain wildcards). Include all - * other files. - * - * Add chosen files to the output. - */ -static void -write_kernel_modules (const char *sourcedir, const char *modpath) -{ - char *tmp = xasprintf ("%s/kmod.whitelist", sourcedir); - char **whitelist = load_file (tmp); - free (tmp); - - char *paths[2] = { (char *) modpath, NULL }; - FTS *fts = fts_open (paths, FTS_COMFOLLOW|FTS_PHYSICAL, NULL); - if (fts == NULL) - error (EXIT_FAILURE, errno, "write_kernel_modules: fts_open: %s", modpath); - - for (;;) { - errno = 0; - FTSENT *entry = fts_read (fts); - if (entry == NULL && errno != 0) - error (EXIT_FAILURE, errno, "write_kernel_modules: fts_read: %s", modpath); - if (entry == NULL) - break; - - /* Ignore directories being visited in post-order. */ - if (entry->fts_info & FTS_DP) - continue; - - /* Is it a *.ko file? */ - if (entry->fts_namelen >= 3 && - entry->fts_name[entry->fts_namelen-3] == '.' && - entry->fts_name[entry->fts_namelen-2] == 'k' && - entry->fts_name[entry->fts_namelen-1] == 'o') { - /* Is it a *.ko file which is on the whitelist? */ - size_t j; - for (j = 0; whitelist[j] != NULL; ++j) { - int r; - r = fnmatch (whitelist[j], entry->fts_name, 0); - if (r == 0) { - /* It's on the whitelist, so include it. */ - if (verbose >= 2) - fprintf (stderr, "including kernel module %s (matches whitelist entry %s)\n", - entry->fts_name, whitelist[j]); - cpio_append_fts_entry (entry); - break; - } else if (r != FNM_NOMATCH) - error (EXIT_FAILURE, 0, "internal error: fnmatch ('%s', '%s', %d) returned unexpected non-zero value %d\n", - whitelist[j], entry->fts_name, 0, r); - } /* for (j) */ - } else - /* It's some other sort of file, or a directory, always include. */ - cpio_append_fts_entry (entry); - } - - if (fts_close (fts) == -1) - error (EXIT_FAILURE, errno, "write_kernel_modules: fts_close: %s", modpath); -} - -/* Copy the host files. - * - * Read the list of entries in *.supermin.hostfiles (which may contain - * wildcards). Look them up in the filesystem, and add those files - * that exist. Ignore any files that don't exist or are not readable. - */ -static void -write_hostfiles (const char *sourcedir, const char *hostcpu, const char *repo) -{ - char *tmp = xasprintf ("%s/initramfs.%s.%s.supermin.hostfiles", - sourcedir, repo, hostcpu); - char **hostfiles = load_file (tmp); - free (tmp); - - /* Hostfiles list can contain "." before each path - ignore it. - * It also contains each directory name before we enter it. But - * we don't read that until we see a wildcard for that directory. - */ - size_t i, j; - for (i = 0; hostfiles[i] != NULL; ++i) { - char *hostfile = hostfiles[i]; - if (hostfile[0] == '.') - hostfile++; - - struct stat statbuf; - - /* Is it a wildcard? */ - if (strchr (hostfile, '*') || strchr (hostfile, '?')) { - char *dirname = xstrdup (hostfile); - char *patt = strrchr (dirname, '/'); - assert (patt); - *patt++ = '\0'; - - char **files = read_dir (dirname); - files = filter_fnmatch (files, patt, FNM_NOESCAPE); - - /* Add matching files. */ - for (j = 0; files[j] != NULL; ++j) { - tmp = xasprintf ("%s/%s", dirname, files[j]); - - if (verbose >= 2) - fprintf (stderr, "including host file %s (matches %s)\n", tmp, patt); - - cpio_append (tmp); - - free (tmp); - } - } - /* Else does this file/directory/whatever exist? */ - else if (lstat (hostfile, &statbuf) == 0) { - if (verbose >= 2) - fprintf (stderr, "including host file %s (directly referenced)\n", - hostfile); - - cpio_append_stat (hostfile, &statbuf); - } /* Ignore files that don't exist. */ - } -} - -/*----------*/ -/* Helper functions. */ - -static void -add_string (char ***argv, size_t *n_used, size_t *n_alloc, const char *str) -{ - char **new_argv; - char *new_str; - - if (*n_used >= *n_alloc) - *argv = x2nrealloc (*argv, n_alloc, sizeof (char *)); - - if (str) - new_str = xstrdup (str); - else - new_str = NULL; - - (*argv)[*n_used] = new_str; - - (*n_used)++; -} - -static size_t -count_strings (char *const *argv) -{ - size_t argc; - - for (argc = 0; argv[argc] != NULL; ++argc) - ; - return argc; -} - -struct dir_cache { - char *path; - char **files; -}; - -static size_t -dir_cache_hash (void const *x, size_t table_size) -{ - struct dir_cache const *p = x; - return hash_pjw (p->path, table_size); -} - -static bool -dir_cache_compare (void const *x, void const *y) -{ - struct dir_cache const *p = x; - struct dir_cache const *q = y; - return strcmp (p->path, q->path) == 0; -} - -/* Read a directory into a list of strings. - * - * Previously looked up directories are cached and returned quickly, - * saving some considerable amount of time compared to reading the - * directory over again. However this means you really must not - * alter the array of strings that are returned. - * - * Returns an empty list if the directory cannot be opened. - */ -static char ** -read_dir (const char *name) -{ - static Hash_table *ht = NULL; - - if (!ht) - ht = hash_initialize (1024, NULL, dir_cache_hash, dir_cache_compare, NULL); - - struct dir_cache key = { .path = (char *) name }; - struct dir_cache *p = hash_lookup (ht, &key); - if (p) - return p->files; - - char **files = NULL; - size_t n_used = 0, n_alloc = 0; - - DIR *dir = opendir (name); - if (!dir) { - /* If it fails to open, that's OK, skip to the end. */ - /*perror (name);*/ - goto done; - } - - for (;;) { - errno = 0; - struct dirent *d = readdir (dir); - if (d == NULL) { - if (errno != 0) - /* But if it fails here, after opening and potentially reading - * part of the directory, that's a proper failure - inform the - * user and exit. - */ - error (EXIT_FAILURE, errno, "%s", name); - break; - } - - add_string (&files, &n_used, &n_alloc, d->d_name); - } - - if (closedir (dir) == -1) - error (EXIT_FAILURE, errno, "closedir: %s", name); - - done: - /* NULL-terminate the array. */ - add_string (&files, &n_used, &n_alloc, NULL); - - /* Add it to the hash for next time. */ - p = xmalloc (sizeof *p); - p->path = (char *) name; - p->files = files; - p = hash_insert (ht, p); - assert (p != NULL); - - return files; -} - -/* Filter a list of strings and return only those matching the wildcard. */ -static char ** -filter_fnmatch (char **strings, const char *patt, int flags) -{ - char **out = NULL; - size_t n_used = 0, n_alloc = 0; - - int i, r; - for (i = 0; strings[i] != NULL; ++i) { - r = fnmatch (patt, strings[i], flags); - if (r == 0) - add_string (&out, &n_used, &n_alloc, strings[i]); - else if (r != FNM_NOMATCH) - error (EXIT_FAILURE, 0, "internal error: fnmatch ('%s', '%s', %d) returned unexpected non-zero value %d\n", - patt, strings[i], flags, r); - } - - add_string (&out, &n_used, &n_alloc, NULL); - return out; -} - -/* Filter a list of strings and return only those which DON'T contain sub. */ -static char ** -filter_notmatching_substring (char **strings, const char *sub) -{ - char **out = NULL; - size_t n_used = 0, n_alloc = 0; - - int i; - for (i = 0; strings[i] != NULL; ++i) { - if (strstr (strings[i], sub) == NULL) - add_string (&out, &n_used, &n_alloc, strings[i]); - } - - add_string (&out, &n_used, &n_alloc, NULL); - return out; -} - -/* Sort a list of strings, in place, with the comparison function supplied. */ -static void -sort (char **strings, int (*compare) (const void *, const void *)) -{ - qsort (strings, count_strings (strings), sizeof (char *), compare); -} - -/* Return true iff path exists and is a directory. This version - * follows symlinks. - */ -static int -isdir (const char *path) -{ - struct stat statbuf; - - if (stat (path, &statbuf) == -1) - return 0; - - return S_ISDIR (statbuf.st_mode); -} - -/* Copy contents of buffer to out_fd and keep out_offset correct. */ -static void -write_to_fd (const void *buffer, size_t len) -{ - if (full_write (out_fd, buffer, len) != len) - error (EXIT_FAILURE, errno, "write"); - out_offset += len; -} - -/* Copy contents of file to out_fd. */ -static void -write_file_to_fd (const char *filename) -{ - char buffer[BUFFER_SIZE]; - int fd2; - ssize_t r; - - if (verbose >= 2) - fprintf (stderr, "write_file_to_fd %s -> %d\n", filename, out_fd); - - fd2 = open (filename, O_RDONLY); - if (fd2 == -1) - error (EXIT_FAILURE, errno, "open: %s", filename); - for (;;) { - r = read (fd2, buffer, sizeof buffer); - if (r == 0) - break; - if (r == -1) { - if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) - continue; - error (EXIT_FAILURE, errno, "read: %s", filename); - } - write_to_fd (buffer, r); - } - - if (close (fd2) == -1) - error (EXIT_FAILURE, errno, "close: %s", filename); -} - -/* Copy file of given length to output, and fail if the file has - * changed size. - */ -static void -write_file_len_to_fd (const char *filename, size_t len) -{ - char buffer[BUFFER_SIZE]; - size_t count = 0; - - if (verbose >= 2) - fprintf (stderr, "write_file_to_fd %s -> %d\n", filename, out_fd); - - int fd2 = open (filename, O_RDONLY); - if (fd2 == -1) - error (EXIT_FAILURE, errno, "open: %s", filename); - for (;;) { - ssize_t r = read (fd2, buffer, sizeof buffer); - if (r == 0) - break; - if (r == -1) { - if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) - continue; - error (EXIT_FAILURE, errno, "read: %s", filename); - } - write_to_fd (buffer, r); - count += r; - if (count > len) - error (EXIT_FAILURE, 0, "write_file_len_to_fd: %s: file has increased in size\n", filename); - } - - if (close (fd2) == -1) - error (EXIT_FAILURE, errno, "close: %s", filename); - - if (count != len) - error (EXIT_FAILURE, 0, "libguestfs-supermin-helper: write_file_len_to_fd: %s: file has changed size\n", filename); -} - -/* Load in a file, returning a list of lines. */ -static char ** -load_file (const char *filename) -{ - char **lines = 0; - size_t n_used = 0, n_alloc = 0; - - FILE *fp; - fp = fopen (filename, "r"); - if (fp == NULL) - error (EXIT_FAILURE, errno, "fopen: %s", filename); - - char line[4096]; - while (fgets (line, sizeof line, fp)) { - size_t len = strlen (line); - if (len > 0 && line[len-1] == '\n') - line[len-1] = '\0'; - add_string (&lines, &n_used, &n_alloc, line); - } - - add_string (&lines, &n_used, &n_alloc, NULL); - return lines; -} - -/* Append the file pointed to by FTSENT to the cpio output. */ -static void -cpio_append_fts_entry (FTSENT *entry) -{ - if (entry->fts_info & FTS_NS || entry->fts_info & FTS_NSOK) - cpio_append (entry->fts_path); - else - cpio_append_stat (entry->fts_path, entry->fts_statp); -} - -/* Append the file named 'filename' to the cpio output. */ -static void -cpio_append (const char *filename) -{ - struct stat statbuf; - - if (lstat (filename, &statbuf) == -1) - error (EXIT_FAILURE, errno, "lstat: %s", filename); - cpio_append_stat (filename, &statbuf); -} - -/* Append the file to the cpio output. */ -#define PADDING(len) ((((len) + 3) & ~3) - (len)) - -#define CPIO_HEADER_LEN (6 + 13*8) - -static void -cpio_append_stat (const char *filename, struct stat *statbuf) -{ - const char *orig_filename = filename; - - if (*filename == '/') - filename++; - if (*filename == '\0') - filename = "."; - - if (verbose >= 2) - fprintf (stderr, "cpio_append_stat %s 0%o -> %d\n", - orig_filename, statbuf->st_mode, out_fd); - - /* Regular files and symlinks are the only ones that have a "body" - * in this cpio entry. - */ - int has_body = S_ISREG (statbuf->st_mode) || S_ISLNK (statbuf->st_mode); - - size_t len = strlen (filename) + 1; - - char header[CPIO_HEADER_LEN + 1]; - snprintf (header, sizeof header, - "070701" /* magic */ - "%08X" /* inode */ - "%08X" /* mode */ - "%08X" "%08X" /* uid, gid */ - "%08X" /* nlink */ - "%08X" /* mtime */ - "%08X" /* file length */ - "%08X" "%08X" /* device holding file major, minor */ - "%08X" "%08X" /* for specials, device major, minor */ - "%08X" /* name length (including \0 byte) */ - "%08X", /* checksum (not used by the kernel) */ - (unsigned) statbuf->st_ino, statbuf->st_mode, - statbuf->st_uid, statbuf->st_gid, - (unsigned) statbuf->st_nlink, (unsigned) statbuf->st_mtime, - has_body ? (unsigned) statbuf->st_size : 0, - major (statbuf->st_dev), minor (statbuf->st_dev), - major (statbuf->st_rdev), minor (statbuf->st_rdev), - (unsigned) len, 0); - - /* Write the header. */ - write_to_fd (header, CPIO_HEADER_LEN); - - /* Follow with the filename, and pad it. */ - write_to_fd (filename, len); - size_t padding_len = PADDING (CPIO_HEADER_LEN + len); - write_padding (padding_len); - - /* Follow with the file or symlink content, and pad it. */ - if (has_body) { - if (S_ISREG (statbuf->st_mode)) - write_file_len_to_fd (orig_filename, statbuf->st_size); - else if (S_ISLNK (statbuf->st_mode)) { - char tmp[PATH_MAX]; - if (readlink (orig_filename, tmp, sizeof tmp) == -1) - error (EXIT_FAILURE, errno, "readlink: %s", orig_filename); - write_to_fd (tmp, statbuf->st_size); - } - - padding_len = PADDING (statbuf->st_size); - write_padding (padding_len); - } -} - -/* CPIO voodoo. */ -static void -cpio_append_trailer (void) -{ - struct stat statbuf; - memset (&statbuf, 0, sizeof statbuf); - statbuf.st_nlink = 1; - cpio_append_stat ("TRAILER!!!", &statbuf); - - /* CPIO seems to pad up to the next block boundary, ie. up to - * the next 512 bytes. - */ - write_padding (((out_offset + 511) & ~511) - out_offset); - assert ((out_offset & 511) == 0); -} - -/* Write 'len' bytes of zeroes out. */ -static void -write_padding (size_t len) -{ - static const char buffer[512] = { 0 }; - - while (len > 0) { - size_t n = len < sizeof buffer ? len : sizeof buffer; - write_to_fd (buffer, n); - len -= n; - } -} |