Re: [Libguestfs] [PATCH v3 1/5] New API: file-architecture

> From 647be56b2d8b171a33608b36e0b7557d94db3c96 Mon Sep 17 00:00:00 2001 From: Richard Jones<rjones(a)redhat.com> Date: Wed, 28 Jul 2010 15:38:57 +0100 Subject: [PATCH 1/5] New API: file-architecture This change simply converts the existing Perl-only function file_architecture into a core API call. The core API call is written in C and available in all languages and from guestfish. --- README | 2 + configure.ac | 9 ++ perl/lib/Sys/Guestfs/Lib.pm | 147 +----------------------- perl/t/510-lib-file-arch.t | 70 ----------- po/POTFILES.in | 1 + src/Makefile.am | 3 +- src/generator.ml | 128 +++++++++++++++++++++ src/inspect.c | 266 +++++++++++++++++++++++++++++++++++++++++++ 8 files changed, 411 insertions(+), 215 deletions(-) delete mode 100644 perl/t/510-lib-file-arch.t create mode 100644 src/inspect.c

diff --git a/src/inspect.c b/src/inspect.c new file mode 100644 index 0000000..8e28d8a --- /dev/null +++ b/src/inspect.c @@ -0,0 +1,266 @@ +/* libguestfs + * Copyright (C) 2010 Red Hat Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include<config.h> + +#include<stdio.h> +#include<stdlib.h> +#include<stdint.h> +#include<inttypes.h> +#include<unistd.h> +#include<string.h> +#include<sys/stat.h> + +#include<pcre.h> + +#include "ignore-value.h" + +#include "guestfs.h" +#include "guestfs-internal.h" +#include "guestfs-internal-actions.h" +#include "guestfs_protocol.h" + +/* Compile all the regular expressions once when the shared library is + * loaded. PCRE is thread safe so we're supposedly OK here if + * multiple threads call into the libguestfs API functions below + * simultaneously. + */ +static pcre *re_file_elf; +static pcre *re_file_win64; +static pcre *re_elf_ppc64; + +static void compile_regexps (void) __attribute__((constructor)); +static void +compile_regexps (void) +{ + const char *err; + int offset; + +#define COMPILE(re,pattern,options) \ + do { \ + re = pcre_compile ((pattern), (options),&err,&offset, NULL); \ + if (re == NULL) { \ + ignore_value (write (2, err, strlen (err))); \ + abort (); \ + } \ + } while (0) + + COMPILE (re_file_elf, + "ELF.*(?:executable|shared object|relocatable), (.+?),", 0); + COMPILE (re_file_win64, "PE32\\+ executable", 0); + COMPILE (re_elf_ppc64, "64.*PowerPC", 0); +} + +/* Match a regular expression which contains no captures. Returns + * true if it matches or false if it doesn't. + */ +static int +match (const char *str, const pcre *re) +{ + size_t len = strlen (str); + int vec[30], r; + + r = pcre_exec (re, NULL, str, len, 0, 0, vec, 30);

+ if (r == PCRE_ERROR_NOMATCH) + return 0; + if (r != 1) { + /* Internal error -- should not happen. */ + fprintf (stderr, "libguestfs: %s: %s: internal error: pcre_exec returned unexpected error code %d when matching against the string \"%s\"\n", + __FILE__, __func__, r, str); + return 0; + } + + return 1; +} + +/* Match a regular expression which contains exactly one capture. If + * the string matches, return the capture, otherwise return NULL. The + * caller must free the result. + */ +static char * +match1 (const char *str, const pcre *re) +{ + size_t len = strlen (str); + int vec[30], r; + + r = pcre_exec (re, NULL, str, len, 0, 0, vec, 30);

+ if (r == PCRE_ERROR_NOMATCH) + return NULL; + if (r != 2) { + /* Internal error -- should not happen. */ + fprintf (stderr, "libguestfs: %s: %s: internal error: pcre_exec returned unexpected error code %d when matching against the string \"%s\"\n", + __FILE__, __func__, r, str); + return NULL; + } + + return strndup (&str[vec[2]], vec[3]-vec[2]);

+} + +/* Convert output from 'file' command on ELF files to the canonical + * architecture string. Caller must free the result. + */ +static char * +canonical_elf_arch (guestfs_h *g, const char *elf_arch) +{ + const char *r; + + if (strstr (elf_arch, "Intel 80386")) + r = "i386"; + else if (strstr (elf_arch, "Intel 80486")) + r = "i486"; + else if (strstr (elf_arch, "x86-64")) + r = "x86_64"; + else if (strstr (elf_arch, "AMD x86-64")) + r = "x86_64"; + else if (strstr (elf_arch, "SPARC32")) + r = "sparc"; + else if (strstr (elf_arch, "SPARC V9")) + r = "sparc64"; + else if (strstr (elf_arch, "IA-64")) + r = "ia64"; + else if (match (elf_arch, re_elf_ppc64)) + r = "ppc64"; + else if (strstr (elf_arch, "PowerPC")) + r = "ppc"; + else + r = elf_arch; + + char *ret = safe_strdup (g, r); + return ret; +} + +static int +is_regular_file (const char *filename) +{ + struct stat statbuf; + + return lstat (filename,&statbuf) == 0&& S_ISREG (statbuf.st_mode); +} + +/* Download and uncompress the cpio file to find binaries within. */ +#define INITRD_BINARIES1 "bin/ls bin/rm bin/modprobe sbin/modprobe bin/sh bin/bash bin/dash bin/nash" +#define INITRD_BINARIES2 {"bin/ls", "bin/rm", "bin/modprobe", "sbin/modprobe", "bin/sh", "bin/bash", "bin/dash", "bin/nash"}

+ +static char * +cpio_arch (guestfs_h *g, const char *file, const char *path) +{

+ char *ret = NULL; + + const char *method; + if (strstr (file, "gzip")) + method = "zcat"; + else if (strstr (file, "bzip2")) + method = "bzcat"; + else + method = "cat"; + + char dir[] = "/tmp/initrd.XXXXXX"; +#define dir_len 18

+ if (mkdtemp (dir) == NULL) { + perrorf (g, "mkdtemp"); + goto out; + } + + char dir_initrd[dir_len + 16]; + snprintf (dir_initrd, dir_len + 16, "%s/initrd", dir); + if (guestfs_download (g, path, dir_initrd) == -1) + goto out; + + char cmd[dir_len + 256]; + snprintf (cmd, dir_len + 256, + "cd %s&& %s initrd | cpio --quiet -id " INITRD_BINARIES1, + dir, method); + int r = system (cmd); + if (r == -1 || WEXITSTATUS (r) != 0) { + perrorf (g, "cpio command failed"); + goto out; + } + + char bin[dir_len + 32];

+ const char *bins[] = INITRD_BINARIES2; + size_t i; + for (i = 0; i< sizeof bins / sizeof bins[0]; ++i) { + snprintf (bin, dir_len + 32, "%s/%s", dir, bins[i]);

+ + if (is_regular_file (bin)) { + snprintf (cmd, dir_len + 256, "file %s", bin);

+ FILE *fp = popen (cmd, "r"); + if (!fp) { + perrorf (g, "popen: %s", cmd); + goto out; + } + + char line[1024]; + if (!fgets (line, sizeof line, fp)) { + perrorf (g, "fgets"); + fclose (fp); + goto out; + } + pclose (fp);

+ + char *elf_arch; + if ((elf_arch = match1 (line, re_file_elf)) != NULL) { + ret = canonical_elf_arch (g, elf_arch); + free (elf_arch); + goto out; + } + } + } + error (g, "file_architecture: could not determine architecture of cpio archive"); + + out: + /* Free up the temporary directory. Note the directory name cannot + * contain shell meta-characters because of the way it was + * constructed above. + */ + snprintf (cmd, dir_len + 256, "rm -rf %s", dir);

+ ignore_value (system (cmd)); + + return ret; +#undef dir_len +} + +char * +guestfs__file_architecture (guestfs_h *g, const char *path) +{ + char *file = NULL; + char *elf_arch = NULL; + char *ret = NULL; + + /* Get the output of the "file" command. Note that because this + * runs in the daemon, LANG=C so it's in English. + */ + file = guestfs_file (g, path); + if (file == NULL) + return NULL; + + if ((elf_arch = match1 (file, re_file_elf)) != NULL) + ret = canonical_elf_arch (g, elf_arch); + else if (strstr (file, "PE32 executable")) + ret = safe_strdup (g, "i386"); + else if (match (file, re_file_win64))

+ ret = safe_strdup (g, "x86_64"); + else if (strstr (file, "cpio archive")) + ret = cpio_arch (g, file, path); + else + error (g, "file_architecture: unknown architecture: %s", path); + + free (file); + free (elf_arch); + return ret; /* caller frees */ +} -- 1.7.1