kumquat-buildroot/package/makedevs/makedevs.c
Arnout Vandecappelle c85cd189dc makedevs: make device node creation idempotent
We use makedevs to create device nodes in the target rootfs. However,
this can be called several times, e.g. when building several filesystem
images or when rebuilding. When makedevs is called the second time, the
device node already exists so mknod() errors out.

This wasn't noticed before because fakeroot's mknod() wrapper
(incorrectly) does _not_ error out when the file exists already. Now
we switched from fakeroot to pseudo, the problem becomes apparent.

Before creating the device node, check if it already exists and if so,
if it has the correct device type and number. Change of mode and
ownership is still done.

This approach was preferred over removing the target files before
creating them, which would be simpler. However, when e.g. a file exists
as a normal file and makedevs specifies it as a device node, that
really is an error so we should detect it.

The other types don't have to be changed. The 'd' (directory) type is
already OK because it already only creates directories if they don't
exist yet. The 'f' (file mode) and 'r' (recursive) types only operate
on files and directories that exist already.

Patch also sent upstream to busybox.

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reported-by: Fabio Estevam <festevam@gmail.com>
Tested-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2016-11-05 23:32:59 +01:00

659 lines
16 KiB
C

/* vi: set sw=4 ts=4: */
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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 Library 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <getopt.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <ctype.h>
#include <errno.h>
#include <libgen.h>
#include <stdarg.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifndef __APPLE__
#include <sys/sysmacros.h> /* major() and minor() */
#endif
#include <ftw.h>
#ifdef EXTENDED_ATTRIBUTES
#include <sys/capability.h>
#endif /* EXTENDED_ATTRIBUTES */
const char *bb_applet_name;
uid_t recursive_uid;
gid_t recursive_gid;
unsigned int recursive_mode;
#define PASSWD_PATH "etc/passwd" /* MUST be relative */
#define GROUP_PATH "etc/group" /* MUST be relative */
void bb_verror_msg(const char *s, va_list p)
{
fflush(stdout);
fprintf(stderr, "%s: ", bb_applet_name);
vfprintf(stderr, s, p);
}
void bb_error_msg(const char *s, ...)
{
va_list p;
va_start(p, s);
bb_verror_msg(s, p);
va_end(p);
putc('\n', stderr);
}
void bb_error_msg_and_die(const char *s, ...)
{
va_list p;
va_start(p, s);
bb_verror_msg(s, p);
va_end(p);
putc('\n', stderr);
exit(1);
}
void bb_vperror_msg(const char *s, va_list p)
{
int err=errno;
if(s == 0) s = "";
bb_verror_msg(s, p);
if (*s) s = ": ";
fprintf(stderr, "%s%s\n", s, strerror(err));
}
void bb_perror_msg(const char *s, ...)
{
va_list p;
va_start(p, s);
bb_vperror_msg(s, p);
va_end(p);
}
void bb_perror_msg_and_die(const char *s, ...)
{
va_list p;
va_start(p, s);
bb_vperror_msg(s, p);
va_end(p);
exit(1);
}
FILE *bb_xfopen(const char *path, const char *mode)
{
FILE *fp;
if ((fp = fopen(path, mode)) == NULL)
bb_perror_msg_and_die("%s", path);
return fp;
}
enum {
FILEUTILS_PRESERVE_STATUS = 1,
FILEUTILS_DEREFERENCE = 2,
FILEUTILS_RECUR = 4,
FILEUTILS_FORCE = 8,
FILEUTILS_INTERACTIVE = 16
};
int bb_make_directory (char *path, long mode, int flags)
{
mode_t mask;
const char *fail_msg;
char *s = path;
char c;
struct stat st;
mask = umask(0);
if (mode == -1) {
umask(mask);
mode = (S_IXUSR | S_IXGRP | S_IXOTH |
S_IWUSR | S_IWGRP | S_IWOTH |
S_IRUSR | S_IRGRP | S_IROTH) & ~mask;
} else {
umask(mask & ~0300);
}
do {
c = 0;
if (flags & FILEUTILS_RECUR) { /* Get the parent. */
/* Bypass leading non-'/'s and then subsequent '/'s. */
while (*s) {
if (*s == '/') {
do {
++s;
} while (*s == '/');
c = *s; /* Save the current char */
*s = 0; /* and replace it with nul. */
break;
}
++s;
}
}
if (mkdir(path, 0777) < 0) {
/* If we failed for any other reason than the directory
* already exists, output a diagnostic and return -1.*/
if ((errno != EEXIST && errno != EISDIR)
|| !(flags & FILEUTILS_RECUR)
|| (stat(path, &st) < 0 || !S_ISDIR(st.st_mode))) {
fail_msg = "create";
umask(mask);
break;
}
/* Since the directory exists, don't attempt to change
* permissions if it was the full target. Note that
* this is not an error conditon. */
if (!c) {
umask(mask);
return 0;
}
}
if (!c) {
/* Done. If necessary, updated perms on the newly
* created directory. Failure to update here _is_
* an error.*/
umask(mask);
if ((mode != -1) && (chmod(path, mode) < 0)){
fail_msg = "set permissions of";
break;
}
return 0;
}
/* Remove any inserted nul from the path (recursive mode). */
*s = c;
} while (1);
bb_perror_msg ("Cannot %s directory `%s'", fail_msg, path);
return -1;
}
const char * const bb_msg_memory_exhausted = "memory exhausted";
void *xmalloc(size_t size)
{
void *ptr = malloc(size);
if (ptr == NULL && size != 0)
bb_error_msg_and_die(bb_msg_memory_exhausted);
return ptr;
}
void *xcalloc(size_t nmemb, size_t size)
{
void *ptr = calloc(nmemb, size);
if (ptr == NULL && nmemb != 0 && size != 0)
bb_error_msg_and_die(bb_msg_memory_exhausted);
return ptr;
}
void *xrealloc(void *ptr, size_t size)
{
ptr = realloc(ptr, size);
if (ptr == NULL && size != 0)
bb_error_msg_and_die(bb_msg_memory_exhausted);
return ptr;
}
char *private_get_line_from_file(FILE *file, int c)
{
#define GROWBY (80) /* how large we will grow strings by */
int ch;
int idx = 0;
char *linebuf = NULL;
int linebufsz = 0;
while ((ch = getc(file)) != EOF) {
/* grow the line buffer as necessary */
if (idx > linebufsz - 2) {
linebuf = xrealloc(linebuf, linebufsz += GROWBY);
}
linebuf[idx++] = (char)ch;
if (!ch) return linebuf;
if (c<2 && ch == '\n') {
if (c) {
--idx;
}
break;
}
}
if (linebuf) {
if (ferror(file)) {
free(linebuf);
return NULL;
}
linebuf[idx] = 0;
}
return linebuf;
}
char *bb_get_chomped_line_from_file(FILE *file)
{
return private_get_line_from_file(file, 1);
}
long my_getpwnam(const char *name)
{
struct passwd *myuser;
FILE *stream;
stream = bb_xfopen(PASSWD_PATH, "r");
while(1) {
errno = 0;
myuser = fgetpwent(stream);
if (myuser == NULL)
bb_error_msg_and_die("unknown user name: %s", name);
if (errno)
bb_perror_msg_and_die("fgetpwent");
if (!strcmp(name, myuser->pw_name))
break;
}
fclose(stream);
return myuser->pw_uid;
}
long my_getgrnam(const char *name)
{
struct group *mygroup;
FILE *stream;
stream = bb_xfopen(GROUP_PATH, "r");
while(1) {
errno = 0;
mygroup = fgetgrent(stream);
if (mygroup == NULL)
bb_error_msg_and_die("unknown group name: %s", name);
if (errno)
bb_perror_msg_and_die("fgetgrent");
if (!strcmp(name, mygroup->gr_name))
break;
}
fclose(stream);
return mygroup->gr_gid;
}
unsigned long get_ug_id(const char *s, long (*my_getxxnam)(const char *))
{
unsigned long r;
char *p;
r = strtoul(s, &p, 10);
if (*p || (s == p)) {
r = my_getxxnam(s);
}
return r;
}
char * last_char_is(const char *s, int c)
{
char *sret = (char *)s;
if (sret) {
sret = strrchr(sret, c);
if(sret != NULL && *(sret+1) != 0)
sret = NULL;
}
return sret;
}
void bb_xasprintf(char **string_ptr, const char *format, ...)
{
va_list p;
int r;
va_start(p, format);
r = vasprintf(string_ptr, format, p);
va_end(p);
if (r < 0) {
bb_perror_msg_and_die("bb_xasprintf");
}
}
char *concat_path_file(const char *path, const char *filename)
{
char *outbuf;
char *lc;
if (!path)
path = "";
lc = last_char_is(path, '/');
while (*filename == '/')
filename++;
bb_xasprintf(&outbuf, "%s%s%s", path, (lc==NULL ? "/" : ""), filename);
return outbuf;
}
#ifdef EXTENDED_ATTRIBUTES
int bb_set_xattr(const char *fpath, const char *xattr)
{
cap_t cap, cap_file, cap_new;
char *cap_file_text, *cap_new_text;
ssize_t length;
cap = cap_from_text(xattr);
if (cap == NULL)
bb_perror_msg_and_die("cap_from_text failed for %s", xattr);
cap_file = cap_get_file(fpath);
if (cap_file == NULL) {
/* if no capability was set before, we initialize cap_file */
if (errno != ENODATA)
bb_perror_msg_and_die("cap_get_file failed on %s", fpath);
cap_file = cap_init();
if (!cap_file)
bb_perror_msg_and_die("cap_init failed");
}
if ((cap_file_text = cap_to_text(cap_file, &length)) == NULL)
bb_perror_msg_and_die("cap_to_name failed on %s", fpath);
bb_xasprintf(&cap_new_text, "%s %s", cap_file_text, xattr);
if ((cap_new = cap_from_text(cap_new_text)) == NULL)
bb_perror_msg_and_die("cap_from_text failed on %s", cap_new_text);
if (cap_set_file(fpath, cap_new) == -1)
bb_perror_msg_and_die("cap_set_file failed for %s (xattr = %s)", fpath, xattr);
cap_free(cap);
cap_free(cap_file);
cap_free(cap_file_text);
cap_free(cap_new);
cap_free(cap_new_text);
return 0;
}
#endif /* EXTENDED_ATTRIBUTES */
void bb_show_usage(void)
{
fprintf(stderr, "%s: [-d device_table] rootdir\n\n", bb_applet_name);
fprintf(stderr, "Creates a batch of special files as specified in a device table.\n");
fprintf(stderr, "Device table entries take the form of:\n");
fprintf(stderr, "name type mode user group major minor start increment count\n\n");
fprintf(stderr, "Where name is the file name, type can be one of:\n");
fprintf(stderr, " f A regular file\n");
fprintf(stderr, " d Directory\n");
fprintf(stderr, " r Directory recursively\n");
fprintf(stderr, " c Character special device file\n");
fprintf(stderr, " b Block special device file\n");
fprintf(stderr, " p Fifo (named pipe)\n");
fprintf(stderr, "uid is the user id for the target file, gid is the group id for the\n");
fprintf(stderr, "target file. The rest of the entries (major, minor, etc) apply to\n");
fprintf(stderr, "to device special files. A '-' may be used for blank entries.\n\n");
fprintf(stderr, "For example:\n");
fprintf(stderr, "<name> <type> <mode> <uid> <gid> <major> <minor> <start> <inc> <count>\n");
fprintf(stderr, "/dev d 755 0 0 - - - - -\n");
fprintf(stderr, "/dev/console c 666 0 0 5 1 - - -\n");
fprintf(stderr, "/dev/null c 666 0 0 1 3 0 0 -\n");
fprintf(stderr, "/dev/zero c 666 0 0 1 5 0 0 -\n");
fprintf(stderr, "/dev/hda b 640 0 0 3 0 0 0 -\n");
fprintf(stderr, "/dev/hda b 640 0 0 3 1 1 1 15\n");
fprintf(stderr, "/dev/rtp b 640 0 0 250 0 0 1 5\n");
fprintf(stderr, "/dev/gps b 640 0 0 251 0 1 1 5\n");
fprintf(stderr, "/dev/uio b 640 0 0 252 0 1 2 5\n");
fprintf(stderr, "/dev/uio b 640 0 0 252 1 6 2 5\n\n");
fprintf(stderr, "Will Produce:\n");
fprintf(stderr, "/dev\n");
fprintf(stderr, "/dev/console\n");
fprintf(stderr, "/dev/null\n");
fprintf(stderr, "/dev/zero\n");
fprintf(stderr, "/dev/hda\n");
fprintf(stderr, "/dev/hda[1-15] with minor numbers [1-15]\n");
fprintf(stderr, "/dev/rtp[0-4] with minor numbers [0-4]\n");
fprintf(stderr, "/dev/gps[1-5] with minor numbers [0-4]\n");
fprintf(stderr, "/dev/uio[1-5] with minor numbers 0,2,4,6,8\n");
fprintf(stderr, "/dev/uio[6-10] with minor numbers 1,3,5,7,9\n");
exit(1);
}
int bb_recursive(const char *fpath, const struct stat *sb,
int tflag, struct FTW *ftwbuf){
if (chown(fpath, recursive_uid, recursive_gid) == -1) {
bb_perror_msg("chown failed for %s", fpath);
return -1;
}
if (recursive_mode != -1) {
if (chmod(fpath, recursive_mode) < 0) {
bb_perror_msg("chmod failed for %s", fpath);
return -1;
}
}
return 0;
}
int main(int argc, char **argv)
{
int opt;
FILE *table = stdin;
char *rootdir = NULL;
char *full_name = NULL;
char *line = NULL;
int linenum = 0;
int ret = EXIT_SUCCESS;
bb_applet_name = basename(argv[0]);
while ((opt = getopt(argc, argv, "d:")) != -1) {
switch(opt) {
case 'd':
table = bb_xfopen((line=optarg), "r");
break;
default:
bb_show_usage();
}
}
if (optind >= argc || (rootdir=argv[optind])==NULL) {
bb_error_msg_and_die("root directory not speficied");
}
if (chdir(rootdir) != 0) {
bb_perror_msg_and_die("Couldnt chdir to %s", rootdir);
}
umask(0);
printf("rootdir=%s\n", rootdir);
if (line) {
printf("table='%s'\n", line);
} else {
printf("table=<stdin>\n");
}
while ((line = bb_get_chomped_line_from_file(table))) {
char type;
unsigned int mode = 0755;
unsigned int major = 0;
unsigned int minor = 0;
unsigned int count = 0;
unsigned int increment = 0;
unsigned int start = 0;
char xattr[255];
char name[4096];
char user[41];
char group[41];
uid_t uid;
gid_t gid;
linenum++;
if (1 == sscanf(line, "|xattr %254s", xattr)) {
#ifdef EXTENDED_ATTRIBUTES
if (!full_name)
bb_error_msg_and_die("line %d should be after a file\n", linenum);
if (bb_set_xattr(full_name, xattr) < 0)
bb_error_msg_and_die("can't set cap %s on file %s\n", xattr, full_name);
#else
bb_error_msg_and_die("line %d not supported: '%s'\nDid you forget to enable "
"BR2_ROOTFS_DEVICE_TABLE_SUPPORTS_EXTENDED_ATTRIBUTES?\n",
linenum, line);
#endif /* EXTENDED_ATTRIBUTES */
continue;
}
if ((2 > sscanf(line, "%4095s %c %o %40s %40s %u %u %u %u %u", name,
&type, &mode, user, group, &major,
&minor, &start, &increment, &count)) ||
((major | minor | start | count | increment) > 0xfffff))
{
if (*line=='\0' || *line=='#' || isspace(*line))
continue;
bb_error_msg("line %d invalid: '%s'\n", linenum, line);
ret = EXIT_FAILURE;
continue;
}
if (name[0] == '#') {
continue;
}
if (*group) {
gid = get_ug_id(group, my_getgrnam);
} else {
gid = getgid();
}
if (*user) {
uid = get_ug_id(user, my_getpwnam);
} else {
uid = getuid();
}
/*
* free previous full name
* we don't de-allocate full_name at the end of the parsing,
* because we may need it if the next line is an xattr.
*/
free(full_name);
full_name = concat_path_file(rootdir, name);
if (type == 'd') {
bb_make_directory(full_name, mode | S_IFDIR, FILEUTILS_RECUR);
if (chown(full_name, uid, gid) == -1) {
bb_perror_msg("line %d: chown failed for %s", linenum, full_name);
ret = EXIT_FAILURE;
goto loop;
}
if ((mode != -1) && (chmod(full_name, mode) < 0)){
bb_perror_msg("line %d: chmod failed for %s", linenum, full_name);
ret = EXIT_FAILURE;
goto loop;
}
} else if (type == 'f') {
struct stat st;
if ((stat(full_name, &st) < 0 || !S_ISREG(st.st_mode))) {
bb_perror_msg("line %d: regular file '%s' does not exist", linenum, full_name);
ret = EXIT_FAILURE;
goto loop;
}
if (chown(full_name, uid, gid) == -1) {
bb_perror_msg("line %d: chown failed for %s", linenum, full_name);
ret = EXIT_FAILURE;
goto loop;
}
if ((mode != -1) && (chmod(full_name, mode) < 0)){
bb_perror_msg("line %d: chmod failed for %s", linenum, full_name);
ret = EXIT_FAILURE;
goto loop;
}
} else if (type == 'r') {
recursive_uid = uid;
recursive_gid = gid;
recursive_mode = mode;
if (nftw(full_name, bb_recursive, 20, FTW_MOUNT | FTW_PHYS) < 0) {
bb_perror_msg("line %d: recursive failed for %s", linenum, full_name);
ret = EXIT_FAILURE;
goto loop;
}
} else
{
dev_t rdev;
unsigned i;
char *full_name_inc;
struct stat st;
if (type == 'p') {
mode |= S_IFIFO;
}
else if (type == 'c') {
mode |= S_IFCHR;
}
else if (type == 'b') {
mode |= S_IFBLK;
} else {
bb_error_msg("line %d: Unsupported file type %c", linenum, type);
ret = EXIT_FAILURE;
goto loop;
}
full_name_inc = xmalloc(strlen(full_name) + sizeof(int)*3 + 2);
if (count)
count--;
for (i = start; i <= start + count; i++) {
sprintf(full_name_inc, count ? "%s%u" : "%s", full_name, i);
rdev = makedev(major, minor + (i - start) * increment);
if (stat(full_name_inc, &st) == 0) {
if ((mode & S_IFMT) != (st.st_mode & S_IFMT)) {
bb_error_msg("line %d: node %s exists but is of wrong file type", linenum, full_name_inc);
ret = EXIT_FAILURE;
continue;
}
if (st.st_rdev != rdev) {
bb_error_msg("line %d: node %s exists but is wrong device number", linenum, full_name_inc);
ret = EXIT_FAILURE;
continue;
}
} else if (mknod(full_name_inc, mode, rdev) < 0) {
bb_perror_msg("line %d: can't create node %s", linenum, full_name_inc);
ret = EXIT_FAILURE;
continue;
}
if (chown(full_name_inc, uid, gid) < 0) {
bb_perror_msg("line %d: can't chown %s", linenum, full_name_inc);
ret = EXIT_FAILURE;
} else if (chmod(full_name_inc, mode) < 0) {
bb_perror_msg("line %d: can't chmod %s", linenum, full_name_inc);
ret = EXIT_FAILURE;
}
}
free(full_name_inc);
}
loop:
free(line);
}
fclose(table);
return ret;
}