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Diffstat (limited to 'febootstrap-supermin-helper.c')
| -rw-r--r-- | febootstrap-supermin-helper.c | 997 |
1 files changed, 997 insertions, 0 deletions
diff --git a/febootstrap-supermin-helper.c b/febootstrap-supermin-helper.c new file mode 100644 index 0000000..1a43cf2 --- /dev/null +++ b/febootstrap-supermin-helper.c @@ -0,0 +1,997 @@ +/* febootstrap-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 (char **inputs, int nr_inputs, const char *whitelist, const char *modpath, const char *initrd); + +enum { HELP_OPTION = CHAR_MAX + 1 }; + +static const char *options = "k:vV"; +static const struct option long_options[] = { + { "help", 0, 0, HELP_OPTION }, + { "kmods", required_argument, 0, 'k' }, + { "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] inputs [...] whitelist host_cpu kernel initrd\n" + " %s --help\n" + " %s --version\n" + "\n" + "This script is used by febootstrap 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" + " -k file | --kmods file\n" + " Specify kernel module whitelist.\n" + " --verbose | -v\n" + " Enable verbose messages (give multiple times for more verbosity).\n" + " --version | -V\n" + " Display version number and exit.\n", + progname, progname, progname, progname); +} + +int +main (int argc, char *argv[]) +{ + /* First thing: start the clock. */ + gettimeofday (&start_t, NULL); + + const char *whitelist = 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 'k': + whitelist = optarg; + break; + + case 'v': + verbose++; + break; + + case 'V': + printf (PACKAGE_NAME " " PACKAGE_VERSION "\n"); + exit (EXIT_SUCCESS); + + default: + usage (argv[0]); + exit (EXIT_FAILURE); + } + } + + char **inputs = &argv[optind]; + int nr_inputs = argc - optind - 3; + + if (nr_inputs < 1) { + usage (argv[0]); + exit (EXIT_FAILURE); + } + + /* See: https://bugzilla.redhat.com/show_bug.cgi?id=558593 */ + const char *hostcpu = argv[argc-3]; + + /* Output files. */ + const char *kernel = argv[argc-2]; + const char *initrd = argv[argc-1]; + + if (verbose) { + print_timestamped_message ("whitelist = %s, " + "host_cpu = %s, " + "kernel = %s, " + "initrd = %s", + whitelist ? : "(not specified)", + hostcpu, kernel, initrd); + int i; + for (i = 0; i < nr_inputs; ++i) + print_timestamped_message ("inputs[%d] = %s", i, inputs[i]); + } + + /* 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 (inputs, nr_inputs, whitelist, 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, + "febootstrap-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" + "febootstrap use, you shouldn't boot the Xen guest with it).\n"); + exit (EXIT_FAILURE); +} + +static void iterate_inputs (char **inputs, int nr_inputs); +static void iterate_input_directory (const char *dirname, int dirfd); +static void write_kernel_modules (const char *whitelist, const char *modpath); +static void write_hostfiles (const char *hostfiles_file); +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. + * format = plain cpio + * (2) The host files which match wildcards in *.supermin.hostfiles. + * input format = plain text, output format = plain cpio + * (3) The modules from modpath which are on the module whitelist. + * output format = plain cpio + * + * The original shell script 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. + * + * This version contains some improvements over the C version written + * for libguestfs, in that we can have multiple base images (or + * hostfiles) or use a directory to store these files. + */ +static void +create_appliance (char **inputs, int nr_inputs, + const char *whitelist, + 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; + + iterate_inputs (inputs, nr_inputs); + + /* Kernel modules (3). */ + write_kernel_modules (whitelist, modpath); + + cpio_append_trailer (); + + /* Finish off and close output file. */ + if (close (out_fd) == -1) + error (EXIT_FAILURE, errno, "close: %s", initrd); +} + +/* Iterate over the inputs to find out what they are, visiting + * directories if specified. + */ +static void +iterate_inputs (char **inputs, int nr_inputs) +{ + int i; + for (i = 0; i < nr_inputs; ++i) { + if (verbose) + print_timestamped_message ("visiting %s", inputs[i]); + + int fd = open (inputs[i], O_RDONLY); + if (fd == -1) + error (EXIT_FAILURE, errno, "open: %s", inputs[i]); + + struct stat statbuf; + if (fstat (fd, &statbuf) == -1) + error (EXIT_FAILURE, errno, "fstat: %s", inputs[i]); + + /* Directory? */ + if (S_ISDIR (statbuf.st_mode)) + iterate_input_directory (inputs[i], fd); + else if (S_ISREG (statbuf.st_mode)) { + /* Is it a cpio file? */ + char buf[6]; + if (read (fd, buf, 6) == 6 && memcmp (buf, "070701", 6) == 0) + /* Yes, a cpio file. This is a skeleton appliance, case (1). */ + write_file_to_fd (inputs[i]); + else + /* No, must be hostfiles, case (2). */ + write_hostfiles (inputs[i]); + } + else + error (EXIT_FAILURE, 0, "%s: input is not a regular file or directory", + inputs[i]); + + close (fd); + } +} + +static void +iterate_input_directory (const char *dirname, int dirfd) +{ + char path[PATH_MAX]; + strcpy (path, dirname); + size_t len = strlen (dirname); + path[len++] = '/'; + + char *inputs[] = { path }; + + DIR *dir = fdopendir (dirfd); + if (dir == NULL) + error (EXIT_FAILURE, errno, "fdopendir: %s", dirname); + + struct dirent *d; + while ((errno = 0, d = readdir (dir)) != NULL) { + if (d->d_name[0] == '.') /* ignore ., .. and any hidden files. */ + continue; + + strcpy (&path[len], d->d_name); + iterate_inputs (inputs, 1); + } + + if (errno != 0) + error (EXIT_FAILURE, errno, "readdir: %s", dirname); + + if (closedir (dir) == -1) + error (EXIT_FAILURE, errno, "closedir: %s", dirname); +} + +/* 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. + * + * whitelist_file may be NULL, to include ALL kernel modules. + */ +static void +write_kernel_modules (const char *whitelist_file, const char *modpath) +{ + char **whitelist = NULL; + if (whitelist_file != NULL) + whitelist = load_file (whitelist_file); + + 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') { + if (whitelist) { + /* 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 { /* whitelist == NULL, always include */ + if (verbose >= 2) + fprintf (stderr, "including kernel module %s\n", entry->fts_name); + cpio_append_fts_entry (entry); + } + } 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 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 *hostfiles_file) +{ + char **hostfiles = load_file (hostfiles_file); + + /* 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) { + char *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_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, "febootstrap-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; + } +} |