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Ventoy/SQUASHFS/squashfs-tools-4.4/squashfs-tools/pseudo.c

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/*
* Create a squashfs filesystem. This is a highly compressed read only
* filesystem.
*
* Copyright (c) 2009, 2010, 2012, 2014, 2017, 2019
* Phillip Lougher <phillip@squashfs.org.uk>
*
* 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,
* 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* pseudo.c
*/
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <ctype.h>
#include "pseudo.h"
#include "error.h"
#include "progressbar.h"
#define TRUE 1
#define FALSE 0
extern int read_file(char *filename, char *type, int (parse_line)(char *));
struct pseudo_dev **pseudo_file = NULL;
struct pseudo *pseudo = NULL;
int pseudo_count = 0;
static char *get_component(char *target, char **targname)
{
char *start;
start = target;
while(*target != '/' && *target != '\0')
target ++;
*targname = strndup(start, target - start);
while(*target == '/')
target ++;
return target;
}
/*
* Add pseudo device target to the set of pseudo devices. Pseudo_dev
* describes the pseudo device attributes.
*/
struct pseudo *add_pseudo(struct pseudo *pseudo, struct pseudo_dev *pseudo_dev,
char *target, char *alltarget)
{
char *targname;
int i;
target = get_component(target, &targname);
if(pseudo == NULL) {
pseudo = malloc(sizeof(struct pseudo));
if(pseudo == NULL)
MEM_ERROR();
pseudo->names = 0;
pseudo->count = 0;
pseudo->name = NULL;
}
for(i = 0; i < pseudo->names; i++)
if(strcmp(pseudo->name[i].name, targname) == 0)
break;
if(i == pseudo->names) {
/* allocate new name entry */
pseudo->names ++;
pseudo->name = realloc(pseudo->name, (i + 1) *
sizeof(struct pseudo_entry));
if(pseudo->name == NULL)
MEM_ERROR();
pseudo->name[i].name = targname;
if(target[0] == '\0') {
/* at leaf pathname component */
pseudo->name[i].pseudo = NULL;
pseudo->name[i].pathname = strdup(alltarget);
pseudo->name[i].dev = pseudo_dev;
} else {
/* recurse adding child components */
pseudo->name[i].dev = NULL;
pseudo->name[i].pseudo = add_pseudo(NULL, pseudo_dev,
target, alltarget);
}
} else {
/* existing matching entry */
free(targname);
if(pseudo->name[i].pseudo == NULL) {
/* No sub-directory which means this is the leaf
* component of a pre-existing pseudo file.
*/
if(target[0] != '\0') {
/*
* entry must exist as either a 'd' type or
* 'm' type pseudo file
*/
if(pseudo->name[i].dev->type == 'd' ||
pseudo->name[i].dev->type == 'm')
/* recurse adding child components */
pseudo->name[i].pseudo =
add_pseudo(NULL, pseudo_dev,
target, alltarget);
else {
ERROR_START("%s already exists as a "
"non directory.",
pseudo->name[i].name);
ERROR_EXIT(". Ignoring %s!\n",
alltarget);
}
} else if(memcmp(pseudo_dev, pseudo->name[i].dev,
sizeof(struct pseudo_dev)) != 0) {
ERROR_START("%s already exists as a different "
"pseudo definition.", alltarget);
ERROR_EXIT(" Ignoring!\n");
} else {
ERROR_START("%s already exists as an identical "
"pseudo definition!", alltarget);
ERROR_EXIT(" Ignoring!\n");
}
} else {
if(target[0] == '\0') {
/*
* sub-directory exists, which means we can only
* add a pseudo file of type 'd' or type 'm'
*/
if(pseudo->name[i].dev == NULL &&
(pseudo_dev->type == 'd' ||
pseudo_dev->type == 'm')) {
pseudo->name[i].pathname =
strdup(alltarget);
pseudo->name[i].dev = pseudo_dev;
} else {
ERROR_START("%s already exists as a "
"different pseudo definition.",
pseudo->name[i].name);
ERROR_EXIT(" Ignoring %s!\n",
alltarget);
}
} else
/* recurse adding child components */
add_pseudo(pseudo->name[i].pseudo, pseudo_dev,
target, alltarget);
}
}
return pseudo;
}
/*
* Find subdirectory in pseudo directory referenced by pseudo, matching
* filename. If filename doesn't exist or if filename is a leaf file
* return NULL
*/
struct pseudo *pseudo_subdir(char *filename, struct pseudo *pseudo)
{
int i;
if(pseudo == NULL)
return NULL;
for(i = 0; i < pseudo->names; i++)
if(strcmp(filename, pseudo->name[i].name) == 0)
return pseudo->name[i].pseudo;
return NULL;
}
struct pseudo_entry *pseudo_readdir(struct pseudo *pseudo)
{
if(pseudo == NULL)
return NULL;
while(pseudo->count < pseudo->names) {
if(pseudo->name[pseudo->count].dev != NULL)
return &pseudo->name[pseudo->count++];
else
pseudo->count++;
}
return NULL;
}
int pseudo_exec_file(struct pseudo_dev *dev, int *child)
{
int res, pipefd[2];
res = pipe(pipefd);
if(res == -1) {
ERROR("Executing dynamic pseudo file, pipe failed\n");
return 0;
}
*child = fork();
if(*child == -1) {
ERROR("Executing dynamic pseudo file, fork failed\n");
goto failed;
}
if(*child == 0) {
close(pipefd[0]);
close(STDOUT_FILENO);
res = dup(pipefd[1]);
if(res == -1)
exit(EXIT_FAILURE);
execl("/bin/sh", "sh", "-c", dev->command, (char *) NULL);
exit(EXIT_FAILURE);
}
close(pipefd[1]);
return pipefd[0];
failed:
close(pipefd[0]);
close(pipefd[1]);
return 0;
}
void add_pseudo_file(struct pseudo_dev *dev)
{
pseudo_file = realloc(pseudo_file, (pseudo_count + 1) *
sizeof(struct pseudo_dev *));
if(pseudo_file == NULL)
MEM_ERROR();
dev->pseudo_id = pseudo_count;
pseudo_file[pseudo_count ++] = dev;
}
struct pseudo_dev *get_pseudo_file(int pseudo_id)
{
return pseudo_file[pseudo_id];
}
int read_pseudo_def(char *def)
{
int n, bytes;
int quoted = 0;
unsigned int major = 0, minor = 0, mode;
char type, *ptr;
char suid[100], sgid[100]; /* overflow safe */
char *filename, *name;
char *orig_def = def;
long long uid, gid;
struct pseudo_dev *dev;
/*
* Scan for filename, don't use sscanf() and "%s" because
* that can't handle filenames with spaces.
*
* Filenames with spaces should either escape (backslash) the
* space or use double quotes.
*/
filename = malloc(strlen(def) + 1);
if(filename == NULL)
MEM_ERROR();
for(name = filename; (quoted || !isspace(*def)) && *def != '\0';) {
if(*def == '"') {
quoted = !quoted;
def ++;
continue;
}
if(*def == '\\') {
def ++;
if (*def == '\0')
break;
}
*name ++ = *def ++;
}
*name = '\0';
/* Skip any leading slashes (/) */
for(name = filename; *name == '/'; name ++);
if(*name == '\0') {
ERROR("Not enough or invalid arguments in pseudo file "
"definition \"%s\"\n", orig_def);
goto error;
}
n = sscanf(def, " %c %o %99s %99s %n", &type, &mode, suid, sgid,
&bytes);
def += bytes;
if(n < 4) {
ERROR("Not enough or invalid arguments in pseudo file "
"definition \"%s\"\n", orig_def);
switch(n) {
case -1:
/* FALLTHROUGH */
case 0:
/* FALLTHROUGH */
case 1:
ERROR("Couldn't parse filename, type or octal mode\n");
ERROR("If the filename has spaces, either quote it, or "
"backslash the spaces\n");
break;
case 2:
ERROR("Read filename, type and mode, but failed to "
"read or match uid\n");
break;
default:
ERROR("Read filename, type, mode and uid, but failed "
"to read or match gid\n");
break;
}
goto error;
}
switch(type) {
case 'b':
/* FALLTHROUGH */
case 'c':
n = sscanf(def, "%u %u %n", &major, &minor, &bytes);
def += bytes;
if(n < 2) {
ERROR("Not enough or invalid arguments in %s device "
"pseudo file definition \"%s\"\n", type == 'b' ?
"block" : "character", orig_def);
if(n < 1)
ERROR("Read filename, type, mode, uid and gid, "
"but failed to read or match major\n");
else
ERROR("Read filename, type, mode, uid, gid "
"and major, but failed to read or "
"match minor\n");
goto error;
}
if(major > 0xfff) {
ERROR("Major %d out of range\n", major);
goto error;
}
if(minor > 0xfffff) {
ERROR("Minor %d out of range\n", minor);
goto error;
}
/* FALLTHROUGH */
case 'd':
/* FALLTHROUGH */
case 'm':
/*
* Check for trailing junk after expected arguments
*/
if(def[0] != '\0') {
ERROR("Unexpected tailing characters in pseudo file "
"definition \"%s\"\n", orig_def);
goto error;
}
break;
case 'f':
if(def[0] == '\0') {
ERROR("Not enough arguments in dynamic file pseudo "
"definition \"%s\"\n", orig_def);
ERROR("Expected command, which can be an executable "
"or a piece of shell script\n");
goto error;
}
break;
case 's':
if(def[0] == '\0') {
ERROR("Not enough arguments in symlink pseudo "
"definition \"%s\"\n", orig_def);
ERROR("Expected symlink\n");
goto error;
}
if(strlen(def) > 65535) {
ERROR("Symlink pseudo definition %s is greater than 65535"
" bytes!\n", def);
goto error;
}
break;
default:
ERROR("Unsupported type %c\n", type);
goto error;
}
if(mode > 07777) {
ERROR("Mode %o out of range\n", mode);
goto error;
}
uid = strtoll(suid, &ptr, 10);
if(*ptr == '\0') {
if(uid < 0 || uid > ((1LL << 32) - 1)) {
ERROR("Uid %s out of range\n", suid);
goto error;
}
} else {
struct passwd *pwuid = getpwnam(suid);
if(pwuid)
uid = pwuid->pw_uid;
else {
ERROR("Uid %s invalid uid or unknown user\n", suid);
goto error;
}
}
gid = strtoll(sgid, &ptr, 10);
if(*ptr == '\0') {
if(gid < 0 || gid > ((1LL << 32) - 1)) {
ERROR("Gid %s out of range\n", sgid);
goto error;
}
} else {
struct group *grgid = getgrnam(sgid);
if(grgid)
gid = grgid->gr_gid;
else {
ERROR("Gid %s invalid uid or unknown user\n", sgid);
goto error;
}
}
switch(type) {
case 'b':
mode |= S_IFBLK;
break;
case 'c':
mode |= S_IFCHR;
break;
case 'd':
mode |= S_IFDIR;
break;
case 'f':
mode |= S_IFREG;
break;
case 's':
/* permissions on symlinks are always rwxrwxrwx */
mode = 0777 | S_IFLNK;
break;
}
dev = malloc(sizeof(struct pseudo_dev));
if(dev == NULL)
MEM_ERROR();
dev->type = type;
dev->mode = mode;
dev->uid = uid;
dev->gid = gid;
dev->major = major;
dev->minor = minor;
if(type == 'f') {
dev->command = strdup(def);
add_pseudo_file(dev);
}
if(type == 's')
dev->symlink = strdup(def);
pseudo = add_pseudo(pseudo, dev, name, name);
free(filename);
return TRUE;
error:
ERROR("Pseudo definitions should be of the format\n");
ERROR("\tfilename d mode uid gid\n");
ERROR("\tfilename m mode uid gid\n");
ERROR("\tfilename b mode uid gid major minor\n");
ERROR("\tfilename c mode uid gid major minor\n");
ERROR("\tfilename f mode uid gid command\n");
ERROR("\tfilename s mode uid gid symlink\n");
free(filename);
return FALSE;
}
int read_pseudo_file(char *filename)
{
return read_file(filename, "pseudo", read_pseudo_def);
}
struct pseudo *get_pseudo()
{
return pseudo;
}
#ifdef SQUASHFS_TRACE
static void dump_pseudo(struct pseudo *pseudo, char *string)
{
int i, res;
char *path;
for(i = 0; i < pseudo->names; i++) {
struct pseudo_entry *entry = &pseudo->name[i];
if(string) {
res = asprintf(&path, "%s/%s", string, entry->name);
if(res == -1)
BAD_ERROR("asprintf failed in dump_pseudo\n");
} else
path = entry->name;
if(entry->dev)
ERROR("%s %c 0%o %d %d %d %d\n", path, entry->dev->type,
entry->dev->mode & ~S_IFMT, entry->dev->uid,
entry->dev->gid, entry->dev->major,
entry->dev->minor);
if(entry->pseudo)
dump_pseudo(entry->pseudo, path);
if(string)
free(path);
}
}
void dump_pseudos()
{
if (pseudo)
dump_pseudo(pseudo, NULL);
}
#else
void dump_pseudos()
{
}
#endif
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