e2fsprogs/misc/e2initrd_helper.c
Jim Meyering 45e338f533 remove useless if-before-free tests
In case you're wondering about whether this change is safe from a
portability standpoint, fear not.  This has been beaten to death
in other forums.  Here are a few threads:

  http://thread.gmane.org/gmane.comp.version-control.git/74187
  http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/12712
  http://thread.gmane.org/gmane.emacs.devel/98144
  http://thread.gmane.org/gmane.comp.lib.glibc.alpha/13092

There has been debate about whether it's a good idea from a
performance standpoint, too, but imho you'll have a hard time
finding an instance where this sort of change induces a
measurable performance penalty.  If you do, please let me know.

Signed-off-by: Jim Meyering <meyering@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2009-03-08 20:37:12 -04:00

389 lines
6.5 KiB
C

/*
* e2initrd_helper.c - Get the filesystem table
*
* Copyright 2004 by Theodore Ts'o.
*
* %Begin-Header%
* This file may be redistributed under the terms of the GNU Public
* License.
* %End-Header%
*/
#include <stdio.h>
#include <unistd.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <ctype.h>
#include <string.h>
#include <time.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <utime.h>
#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
extern int optind;
extern char *optarg;
#endif
#include "ext2fs/ext2_fs.h"
#include "ext2fs/ext2fs.h"
#include "blkid/blkid.h"
#include "../version.h"
#include "nls-enable.h"
const char * program_name = "get_fstab";
char * device_name;
static int open_flag;
static int root_type;
static blkid_cache cache = NULL;
struct mem_file {
char *buf;
int size;
int ptr;
};
struct fs_info {
char *device;
char *mountpt;
char *type;
char *opts;
int freq;
int passno;
int flags;
struct fs_info *next;
};
static void usage(void)
{
fprintf(stderr,
_("Usage: %s -r device\n"), program_name);
exit (1);
}
static errcode_t get_file(ext2_filsys fs, const char * filename,
struct mem_file *ret_file)
{
errcode_t retval;
char *buf;
ext2_file_t e2_file;
unsigned int got;
struct ext2_inode inode;
ext2_ino_t ino;
ret_file->buf = 0;
ret_file->size = 0;
ret_file->ptr = 0;
retval = ext2fs_namei(fs, EXT2_ROOT_INO, EXT2_ROOT_INO,
filename, &ino);
if (retval)
return retval;
retval = ext2fs_read_inode(fs, ino, &inode);
if (retval)
return retval;
if (inode.i_size_high || (inode.i_size > 65536))
return EFBIG;
buf = malloc(inode.i_size + 1);
if (!buf)
return ENOMEM;
memset(buf, 0, inode.i_size+1);
retval = ext2fs_file_open(fs, ino, 0, &e2_file);
if (retval)
return retval;
retval = ext2fs_file_read(e2_file, buf, inode.i_size, &got);
if (retval)
goto errout;
retval = ext2fs_file_close(e2_file);
if (retval)
return retval;
ret_file->buf = buf;
ret_file->size = (int) got;
errout:
ext2fs_file_close(e2_file);
return retval;
}
static char *get_line(struct mem_file *file)
{
char *cp, *ret;
int s = 0;
cp = file->buf + file->ptr;
while (*cp && *cp != '\n') {
cp++;
s++;
}
ret = malloc(s+1);
if (!ret)
return 0;
ret[s]=0;
memcpy(ret, file->buf + file->ptr, s);
while (*cp && (*cp == '\n' || *cp == '\r')) {
cp++;
s++;
}
file->ptr += s;
return ret;
}
static int mem_file_eof(struct mem_file *file)
{
return (file->ptr >= file->size);
}
/*
* fstab parsing code
*/
static char *string_copy(const char *s)
{
char *ret;
if (!s)
return 0;
ret = malloc(strlen(s)+1);
if (ret)
strcpy(ret, s);
return ret;
}
static char *skip_over_blank(char *cp)
{
while (*cp && isspace(*cp))
cp++;
return cp;
}
static char *skip_over_word(char *cp)
{
while (*cp && !isspace(*cp))
cp++;
return cp;
}
static char *parse_word(char **buf)
{
char *word, *next;
word = *buf;
if (*word == 0)
return 0;
word = skip_over_blank(word);
next = skip_over_word(word);
if (*next)
*next++ = 0;
*buf = next;
return word;
}
static void parse_escape(char *word)
{
char *p, *q;
int ac, i;
if (!word)
return;
for (p = word, q = word; *p; p++, q++) {
*q = *p;
if (*p != '\\')
continue;
if (*++p == 0)
break;
if (*p == 't') {
*q = '\t';
continue;
}
if (*p == 'n') {
*q = '\n';
continue;
}
if (!isdigit(*p)) {
*q = *p;
continue;
}
ac = 0;
for (i = 0; i < 3; i++, p++) {
if (!isdigit(*p))
break;
ac = (ac * 8) + (*p - '0');
}
*q = ac;
p--;
}
*q = 0;
}
static int parse_fstab_line(char *line, struct fs_info *fs)
{
char *dev, *device, *mntpnt, *type, *opts, *freq, *passno, *cp;
if ((cp = strchr(line, '#')))
*cp = 0; /* Ignore everything after the comment char */
cp = line;
device = parse_word(&cp);
mntpnt = parse_word(&cp);
type = parse_word(&cp);
opts = parse_word(&cp);
freq = parse_word(&cp);
passno = parse_word(&cp);
if (!device)
return -1; /* Allow blank lines */
if (!mntpnt || !type)
return -1;
parse_escape(device);
parse_escape(mntpnt);
parse_escape(type);
parse_escape(opts);
parse_escape(freq);
parse_escape(passno);
dev = blkid_get_devname(cache, device, NULL);
if (dev)
device = dev;
if (strchr(type, ','))
type = 0;
fs->device = string_copy(device);
fs->mountpt = string_copy(mntpnt);
fs->type = string_copy(type);
fs->opts = string_copy(opts ? opts : "");
fs->freq = freq ? atoi(freq) : -1;
fs->passno = passno ? atoi(passno) : -1;
fs->flags = 0;
fs->next = NULL;
free(dev);
return 0;
}
static void free_fstab_line(struct fs_info *fs)
{
if (fs->device)
fs->device = 0;
if (fs->mountpt)
fs->mountpt = 0;
if (fs->type)
fs->type = 0;
if (fs->opts)
fs->opts = 0;
memset(fs, 0, sizeof(struct fs_info));
}
static void PRS(int argc, char **argv)
{
int c;
#ifdef ENABLE_NLS
setlocale(LC_MESSAGES, "");
setlocale(LC_CTYPE, "");
bindtextdomain(NLS_CAT_NAME, LOCALEDIR);
textdomain(NLS_CAT_NAME);
#endif
while ((c = getopt(argc, argv, "rv")) != EOF) {
switch (c) {
case 'r':
root_type++;
break;
case 'v':
printf("%s %s (%s)\n", program_name,
E2FSPROGS_VERSION, E2FSPROGS_DATE);
break;
default:
usage();
}
}
if (optind < argc - 1 || optind == argc)
usage();
device_name = blkid_get_devname(NULL, argv[optind], NULL);
if (!device_name) {
com_err("tune2fs", 0, _("Unable to resolve '%s'"),
argv[optind]);
exit(1);
}
}
static void get_root_type(ext2_filsys fs)
{
errcode_t retval;
struct mem_file file;
char *buf;
struct fs_info fs_info;
int ret;
retval = get_file(fs, "/etc/fstab", &file);
while (!mem_file_eof(&file)) {
buf = get_line(&file);
if (!buf)
continue;
ret = parse_fstab_line(buf, &fs_info);
if (ret < 0)
goto next_line;
if (!strcmp(fs_info.mountpt, "/"))
printf("%s\n", fs_info.type);
free_fstab_line(&fs_info);
next_line:
free(buf);
}
}
int main (int argc, char ** argv)
{
errcode_t retval;
ext2_filsys fs;
io_manager io_ptr;
add_error_table(&et_ext2_error_table);
blkid_get_cache(&cache, NULL);
PRS(argc, argv);
#ifdef CONFIG_TESTIO_DEBUG
if (getenv("TEST_IO_FLAGS") || getenv("TEST_IO_BLOCK")) {
io_ptr = test_io_manager;
test_io_backing_manager = unix_io_manager;
} else
#endif
io_ptr = unix_io_manager;
retval = ext2fs_open (device_name, open_flag, 0, 0, io_ptr, &fs);
if (retval)
exit(1);
if (root_type)
get_root_type(fs);
remove_error_table(&et_ext2_error_table);
return (ext2fs_close (fs) ? 1 : 0);
}