File: [local] / src / usr.bin / file / file.c (download)
Revision 1.64, Sat Jul 1 21:07:13 2017 UTC (6 years, 11 months ago) by brynet
Branch: MAIN
CVS Tags: OPENBSD_6_2_BASE, OPENBSD_6_2 Changes since 1.63: +3 -1 lines
close open fd after testing files, ensuring that fd isn't stdin.
ok nicm@
|
/* $OpenBSD: file.c,v 1.64 2017/07/01 21:07:13 brynet Exp $ */
/*
* Copyright (c) 2015 Nicholas Marriott <nicm@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <libgen.h>
#include <limits.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include "file.h"
#include "magic.h"
#include "xmalloc.h"
struct input_file {
struct magic *m;
const char *path;
struct stat sb;
int fd;
int error;
char link_path[PATH_MAX];
int link_error;
int link_target;
void *base;
size_t size;
int mapped;
char *result;
};
extern char *__progname;
__dead void usage(void);
static void prepare_input(struct input_file *, const char *);
static void read_link(struct input_file *, const char *);
static void test_file(struct input_file *, size_t);
static int try_stat(struct input_file *);
static int try_empty(struct input_file *);
static int try_access(struct input_file *);
static int try_text(struct input_file *);
static int try_magic(struct input_file *);
static int try_unknown(struct input_file *);
static int bflag;
static int cflag;
static int iflag;
static int Lflag;
static int sflag;
static int Wflag;
static struct option longopts[] = {
{ "brief", no_argument, NULL, 'b' },
{ "dereference", no_argument, NULL, 'L' },
{ "mime", no_argument, NULL, 'i' },
{ "mime-type", no_argument, NULL, 'i' },
{ NULL, 0, NULL, 0 }
};
__dead void
usage(void)
{
fprintf(stderr, "usage: %s [-bchiLsW] file ...\n", __progname);
exit(1);
}
int
main(int argc, char **argv)
{
int opt, idx;
char *home, *magicpath;
struct passwd *pw;
FILE *magicfp = NULL;
struct magic *m;
struct input_file *inf = NULL;
size_t len, width = 0;
if (pledge("stdio rpath getpw id", NULL) == -1)
err(1, "pledge");
for (;;) {
opt = getopt_long(argc, argv, "bchiLsW", longopts, NULL);
if (opt == -1)
break;
switch (opt) {
case 'b':
bflag = 1;
break;
case 'c':
cflag = 1;
break;
case 'h':
Lflag = 0;
break;
case 'i':
iflag = 1;
break;
case 'L':
Lflag = 1;
break;
case 's':
sflag = 1;
break;
case 'W':
Wflag = 1;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (cflag) {
if (argc != 0)
usage();
} else if (argc == 0)
usage();
if (geteuid() != 0 && !issetugid()) {
home = getenv("HOME");
if (home == NULL || *home == '\0') {
pw = getpwuid(getuid());
if (pw != NULL)
home = pw->pw_dir;
else
home = NULL;
}
if (home != NULL) {
xasprintf(&magicpath, "%s/.magic", home);
magicfp = fopen(magicpath, "r");
if (magicfp == NULL)
free(magicpath);
}
}
if (magicfp == NULL) {
magicpath = xstrdup("/etc/magic");
magicfp = fopen(magicpath, "r");
}
if (magicfp == NULL)
err(1, "%s", magicpath);
if (!cflag) {
inf = xcalloc(argc, sizeof *inf);
for (idx = 0; idx < argc; idx++) {
len = strlen(argv[idx]) + 1;
if (len > width)
width = len;
prepare_input(&inf[idx], argv[idx]);
}
}
tzset();
if (pledge("stdio getpw id", NULL) == -1)
err(1, "pledge");
if (geteuid() == 0) {
pw = getpwnam(FILE_USER);
if (pw == NULL)
errx(1, "unknown user %s", FILE_USER);
if (setgroups(1, &pw->pw_gid) != 0)
err(1, "setgroups");
if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0)
err(1, "setresgid");
if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
err(1, "setresuid");
}
if (pledge("stdio", NULL) == -1)
err(1, "pledge");
m = magic_load(magicfp, magicpath, cflag || Wflag);
if (cflag) {
magic_dump(m);
exit(0);
}
fclose(magicfp);
for (idx = 0; idx < argc; idx++) {
inf[idx].m = m;
test_file(&inf[idx], width);
if (inf[idx].fd != -1 && inf[idx].fd != STDIN_FILENO)
close(inf[idx].fd);
}
exit(0);
}
static void
prepare_input(struct input_file *inf, const char *path)
{
int fd, mode, error;
inf->path = path;
if (strcmp(path, "-") == 0) {
if (fstat(STDIN_FILENO, &inf->sb) == -1) {
inf->error = errno;
inf->fd = -1;
return;
}
inf->fd = STDIN_FILENO;
return;
}
if (Lflag)
error = stat(path, &inf->sb);
else
error = lstat(path, &inf->sb);
if (error == -1) {
inf->error = errno;
inf->fd = -1;
return;
}
/* We don't need them, so don't open directories or symlinks. */
mode = inf->sb.st_mode;
if (!S_ISDIR(mode) && !S_ISLNK(mode)) {
fd = open(path, O_RDONLY|O_NONBLOCK);
if (fd == -1 && (errno == ENFILE || errno == EMFILE))
err(1, "open");
} else
fd = -1;
if (S_ISLNK(mode))
read_link(inf, path);
inf->fd = fd;
}
static void
read_link(struct input_file *inf, const char *path)
{
struct stat sb;
char lpath[PATH_MAX];
char *copy, *root;
int used;
ssize_t size;
size = readlink(path, lpath, sizeof lpath - 1);
if (size == -1) {
inf->link_error = errno;
return;
}
lpath[size] = '\0';
if (*lpath == '/')
strlcpy(inf->link_path, lpath, sizeof inf->link_path);
else {
copy = xstrdup(path);
root = dirname(copy);
if (*root == '\0' || strcmp(root, ".") == 0 ||
strcmp (root, "/") == 0)
strlcpy(inf->link_path, lpath, sizeof inf->link_path);
else {
used = snprintf(inf->link_path, sizeof inf->link_path,
"%s/%s", root, lpath);
if (used < 0 || (size_t)used >= sizeof inf->link_path) {
inf->link_error = ENAMETOOLONG;
free(copy);
return;
}
}
free(copy);
}
if (!Lflag && stat(path, &sb) == -1)
inf->link_target = errno;
}
static void *
fill_buffer(int fd, size_t size, size_t *used)
{
static void *buffer;
ssize_t got;
size_t left;
void *next;
if (buffer == NULL)
buffer = xmalloc(FILE_READ_SIZE);
next = buffer;
left = size;
while (left != 0) {
got = read(fd, next, left);
if (got == -1) {
if (errno == EINTR)
continue;
return (NULL);
}
if (got == 0)
break;
next = (char *)next + got;
left -= got;
}
*used = size - left;
return (buffer);
}
static int
load_file(struct input_file *inf)
{
size_t used;
if (inf->sb.st_size == 0 && S_ISREG(inf->sb.st_mode))
return (0); /* empty file */
if (inf->sb.st_size == 0 || inf->sb.st_size > FILE_READ_SIZE)
inf->size = FILE_READ_SIZE;
else
inf->size = inf->sb.st_size;
if (!S_ISREG(inf->sb.st_mode))
goto try_read;
inf->base = mmap(NULL, inf->size, PROT_READ, MAP_PRIVATE, inf->fd, 0);
if (inf->base == MAP_FAILED)
goto try_read;
inf->mapped = 1;
return (0);
try_read:
inf->base = fill_buffer(inf->fd, inf->size, &used);
if (inf->base == NULL) {
xasprintf(&inf->result, "cannot read '%s' (%s)", inf->path,
strerror(errno));
return (1);
}
inf->size = used;
return (0);
}
static int
try_stat(struct input_file *inf)
{
if (inf->error != 0) {
xasprintf(&inf->result, "cannot stat '%s' (%s)", inf->path,
strerror(inf->error));
return (1);
}
if (sflag || strcmp(inf->path, "-") == 0) {
switch (inf->sb.st_mode & S_IFMT) {
case S_IFIFO:
if (strcmp(inf->path, "-") != 0)
break;
case S_IFBLK:
case S_IFCHR:
case S_IFREG:
return (0);
}
}
if (iflag && (inf->sb.st_mode & S_IFMT) != S_IFREG) {
xasprintf(&inf->result, "application/x-not-regular-file");
return (1);
}
switch (inf->sb.st_mode & S_IFMT) {
case S_IFDIR:
xasprintf(&inf->result, "directory");
return (1);
case S_IFLNK:
if (inf->link_error != 0) {
xasprintf(&inf->result, "unreadable symlink '%s' (%s)",
inf->path, strerror(inf->link_error));
return (1);
}
if (inf->link_target == ELOOP)
xasprintf(&inf->result, "symbolic link in a loop");
else if (inf->link_target != 0) {
xasprintf(&inf->result, "broken symbolic link to '%s'",
inf->link_path);
} else {
xasprintf(&inf->result, "symbolic link to '%s'",
inf->link_path);
}
return (1);
case S_IFSOCK:
xasprintf(&inf->result, "socket");
return (1);
case S_IFBLK:
xasprintf(&inf->result, "block special (%ld/%ld)",
(long)major(inf->sb.st_rdev),
(long)minor(inf->sb.st_rdev));
return (1);
case S_IFCHR:
xasprintf(&inf->result, "character special (%ld/%ld)",
(long)major(inf->sb.st_rdev),
(long)minor(inf->sb.st_rdev));
return (1);
case S_IFIFO:
xasprintf(&inf->result, "fifo (named pipe)");
return (1);
}
return (0);
}
static int
try_empty(struct input_file *inf)
{
if (inf->size != 0)
return (0);
if (iflag)
xasprintf(&inf->result, "application/x-empty");
else
xasprintf(&inf->result, "empty");
return (1);
}
static int
try_access(struct input_file *inf)
{
char tmp[256] = "";
if (inf->sb.st_size == 0 && S_ISREG(inf->sb.st_mode))
return (0); /* empty file */
if (inf->fd != -1)
return (0);
if (inf->sb.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH))
strlcat(tmp, "writable, ", sizeof tmp);
if (inf->sb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH))
strlcat(tmp, "executable, ", sizeof tmp);
if (S_ISREG(inf->sb.st_mode))
strlcat(tmp, "regular file, ", sizeof tmp);
strlcat(tmp, "no read permission", sizeof tmp);
inf->result = xstrdup(tmp);
return (1);
}
static int
try_text(struct input_file *inf)
{
const char *type, *s;
int flags;
flags = MAGIC_TEST_TEXT;
if (iflag)
flags |= MAGIC_TEST_MIME;
type = text_get_type(inf->base, inf->size);
if (type == NULL)
return (0);
s = magic_test(inf->m, inf->base, inf->size, flags);
if (s != NULL) {
inf->result = xstrdup(s);
return (1);
}
s = text_try_words(inf->base, inf->size, flags);
if (s != NULL) {
if (iflag)
inf->result = xstrdup(s);
else
xasprintf(&inf->result, "%s %s text", type, s);
return (1);
}
if (iflag)
inf->result = xstrdup("text/plain");
else
xasprintf(&inf->result, "%s text", type);
return (1);
}
static int
try_magic(struct input_file *inf)
{
const char *s;
int flags;
flags = 0;
if (iflag)
flags |= MAGIC_TEST_MIME;
s = magic_test(inf->m, inf->base, inf->size, flags);
if (s != NULL) {
inf->result = xstrdup(s);
return (1);
}
return (0);
}
static int
try_unknown(struct input_file *inf)
{
if (iflag)
xasprintf(&inf->result, "application/x-not-regular-file");
else
xasprintf(&inf->result, "data");
return (1);
}
static void
test_file(struct input_file *inf, size_t width)
{
char *label;
int stop;
stop = 0;
if (!stop)
stop = try_stat(inf);
if (!stop)
stop = try_access(inf);
if (!stop)
stop = load_file(inf);
if (!stop)
stop = try_empty(inf);
if (!stop)
stop = try_magic(inf);
if (!stop)
stop = try_text(inf);
if (!stop)
stop = try_unknown(inf);
if (bflag)
printf("%s\n", inf->result);
else {
if (strcmp(inf->path, "-") == 0)
xasprintf(&label, "/dev/stdin:");
else
xasprintf(&label, "%s:", inf->path);
printf("%-*s %s\n", (int)width, label, inf->result);
free(label);
}
free(inf->result);
if (inf->mapped && inf->base != NULL)
munmap(inf->base, inf->size);
}