shaba/systemd
1
0
Fork 0
mirror of https://github.com/systemd/systemd.git synced 2024-11-13 23:21:08 +03:00
Code
43d08246db
systemd/libudev/libudev-util-private.c
Kay Sievers 99eb7c451c util_unlink_secure(): chmod() before chown()
2009-12-08 18:44:45 +01:00

475 lines
11 KiB
C
Raw Blame History

/*
* libudev - interface to udev device information
*
* Copyright (C) 2003-2009 Kay Sievers <kay.sievers@vrfy.org>
*
* 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 2.1 of the License, or (at your option) any later version.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <pwd.h>
#include <grp.h>
#include <sys/wait.h>
#include <sys/param.h>
#include "libudev.h"
#include "libudev-private.h"
int util_create_path(struct udev *udev, const char *path)
{
char p[UTIL_PATH_SIZE];
char *pos;
struct stat stats;
int err;
util_strscpy(p, sizeof(p), path);
pos = strrchr(p, '/');
if (pos == NULL)
return 0;
while (pos != p && pos[-1] == '/')
pos--;
if (pos == p)
return 0;
pos[0] = '\0';
dbg(udev, "stat '%s'\n", p);
if (stat(p, &stats) == 0) {
if ((stats.st_mode & S_IFMT) == S_IFDIR)
return 0;
else
return -ENOTDIR;
}
err = util_create_path(udev, p);
if (err != 0)
return err;
dbg(udev, "mkdir '%s'\n", p);
udev_selinux_setfscreatecon(udev, p, S_IFDIR|0755);
err = mkdir(p, 0755);
if (err != 0) {
err = -errno;
if (err == -EEXIST && stat(p, &stats) == 0) {
if ((stats.st_mode & S_IFMT) == S_IFDIR)
err = 0;
else
err = -ENOTDIR;
}
}
udev_selinux_resetfscreatecon(udev);
return err;
}
int util_delete_path(struct udev *udev, const char *path)
{
char p[UTIL_PATH_SIZE];
char *pos;
int retval;
if (path[0] == '/')
while(path[1] == '/')
path++;
util_strscpy(p, sizeof(p), path);
pos = strrchr(p, '/');
if (pos == p || pos == NULL)
return 0;
while (1) {
*pos = '\0';
pos = strrchr(p, '/');
/* don't remove the last one */
if ((pos == p) || (pos == NULL))
break;
/* remove if empty */
retval = rmdir(p);
if (errno == ENOENT)
retval = 0;
if (retval) {
if (errno == ENOTEMPTY)
return 0;
err(udev, "rmdir(%s) failed: %m\n", p);
break;
}
dbg(udev, "removed '%s'\n", p);
}
return 0;
}
/* Reset permissions on the device node, before unlinking it to make sure,
* that permissions of possible hard links will be removed too.
*/
int util_unlink_secure(struct udev *udev, const char *filename)
{
int err;
chown(filename, 0, 0);
chmod(filename, 0000);
err = unlink(filename);
if (errno == ENOENT)
err = 0;
if (err)
err(udev, "unlink(%s) failed: %m\n", filename);
return err;
}
uid_t util_lookup_user(struct udev *udev, const char *user)
{
char *endptr;
int buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
char buf[buflen];
struct passwd pwbuf;
struct passwd *pw;
uid_t uid;
if (strcmp(user, "root") == 0)
return 0;
uid = strtoul(user, &endptr, 10);
if (endptr[0] == '\0')
return uid;
errno = getpwnam_r(user, &pwbuf, buf, buflen, &pw);
if (pw != NULL)
return pw->pw_uid;
if (errno == 0 || errno == ENOENT || errno == ESRCH)
err(udev, "specified user '%s' unknown\n", user);
else
err(udev, "error resolving user '%s': %m\n", user);
return 0;
}
gid_t util_lookup_group(struct udev *udev, const char *group)
{
char *endptr;
int buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
char *buf;
struct group grbuf;
struct group *gr;
gid_t gid = 0;
if (strcmp(group, "root") == 0)
return 0;
gid = strtoul(group, &endptr, 10);
if (endptr[0] == '\0')
return gid;
buf = NULL;
gid = 0;
for (;;) {
char *newbuf;
newbuf = realloc(buf, buflen);
if (!newbuf)
break;
buf = newbuf;
errno = getgrnam_r(group, &grbuf, buf, buflen, &gr);
if (gr != NULL) {
gid = gr->gr_gid;
} else if (errno == ERANGE) {
buflen *= 2;
continue;
} else if (errno == 0 || errno == ENOENT || errno == ESRCH) {
err(udev, "specified group '%s' unknown\n", group);
} else {
err(udev, "error resolving group '%s': %m\n", group);
}
break;
}
free(buf);
return gid;
}
/* handle "[<SUBSYSTEM>/<KERNEL>]<attribute>" format */
int util_resolve_subsys_kernel(struct udev *udev, const char *string,
char *result, size_t maxsize, int read_value)
{
char temp[UTIL_PATH_SIZE];
char *subsys;
char *sysname;
struct udev_device *dev;
char *attr;
if (string[0] != '[')
return -1;
util_strscpy(temp, sizeof(temp), string);
subsys = &temp[1];
sysname = strchr(subsys, '/');
if (sysname == NULL)
return -1;
sysname[0] = '\0';
sysname = &sysname[1];
attr = strchr(sysname, ']');
if (attr == NULL)
return -1;
attr[0] = '\0';
attr = &attr[1];
if (attr[0] == '/')
attr = &attr[1];
if (attr[0] == '\0')
attr = NULL;
if (read_value && attr == NULL)
return -1;
dev = udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
if (dev == NULL)
return -1;
if (read_value) {
const char *val;
val = udev_device_get_sysattr_value(dev, attr);
if (val != NULL)
util_strscpy(result, maxsize, val);
else
result[0] = '\0';
info(udev, "value '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
} else {
size_t l;
char *s;
s = result;
l = util_strpcpyl(&s, maxsize, udev_device_get_syspath(dev), NULL);
if (attr != NULL)
util_strpcpyl(&s, l, "/", attr, NULL);
info(udev, "path '[%s/%s]%s' is '%s'\n", subsys, sysname, attr, result);
}
udev_device_unref(dev);
return 0;
}
int util_run_program(struct udev *udev, const char *command, char **envp,
char *result, size_t ressize, size_t *reslen,
const sigset_t *sigmask)
{
int status;
int outpipe[2] = {-1, -1};
int errpipe[2] = {-1, -1};
pid_t pid;
char arg[UTIL_PATH_SIZE];
char program[UTIL_PATH_SIZE];
char *argv[((sizeof(arg) + 1) / 2) + 1];
int devnull;
int i;
int err = 0;
info(udev, "'%s' started\n", command);
/* build argv from command */
util_strscpy(arg, sizeof(arg), command);
i = 0;
if (strchr(arg, ' ') != NULL) {
char *pos = arg;
while (pos != NULL && pos[0] != '\0') {
if (pos[0] == '\'') {
/* do not separate quotes */
pos++;
argv[i] = strsep(&pos, "\'");
if (pos != NULL)
while (pos[0] == ' ')
pos++;
} else {
argv[i] = strsep(&pos, " ");
if (pos != NULL)
while (pos[0] == ' ')
pos++;
}
dbg(udev, "arg[%i] '%s'\n", i, argv[i]);
i++;
}
argv[i] = NULL;
} else {
argv[0] = arg;
argv[1] = NULL;
}
/* prepare pipes from child to parent */
if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
if (pipe(outpipe) != 0) {
err(udev, "pipe failed: %m\n");
return -1;
}
}
if (udev_get_log_priority(udev) >= LOG_INFO) {
if (pipe(errpipe) != 0) {
err(udev, "pipe failed: %m\n");
return -1;
}
}
/* allow programs in /lib/udev/ to be called without the path */
if (argv[0][0] != '/') {
util_strscpyl(program, sizeof(program), LIBEXECDIR "/", argv[0], NULL);
argv[0] = program;
}
pid = fork();
switch(pid) {
case 0:
/* child closes parent ends of pipes */
if (outpipe[READ_END] > 0)
close(outpipe[READ_END]);
if (errpipe[READ_END] > 0)
close(errpipe[READ_END]);
/* discard child output or connect to pipe */
devnull = open("/dev/null", O_RDWR);
if (devnull > 0) {
dup2(devnull, STDIN_FILENO);
if (outpipe[WRITE_END] < 0)
dup2(devnull, STDOUT_FILENO);
if (errpipe[WRITE_END] < 0)
dup2(devnull, STDERR_FILENO);
close(devnull);
} else
err(udev, "open /dev/null failed: %m\n");
if (outpipe[WRITE_END] > 0) {
dup2(outpipe[WRITE_END], STDOUT_FILENO);
close(outpipe[WRITE_END]);
}
if (errpipe[WRITE_END] > 0) {
dup2(errpipe[WRITE_END], STDERR_FILENO);
close(errpipe[WRITE_END]);
}
if (sigmask)
sigprocmask(SIG_SETMASK, sigmask, NULL);
execve(argv[0], argv, envp);
if (errno == ENOENT || errno == ENOTDIR) {
/* may be on a filesystem which is not mounted right now */
info(udev, "program '%s' not found\n", argv[0]);
} else {
/* other problems */
err(udev, "exec of program '%s' failed\n", argv[0]);
}
_exit(1);
case -1:
err(udev, "fork of '%s' failed: %m\n", argv[0]);
return -1;
default:
/* read from child if requested */
if (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
ssize_t count;
size_t respos = 0;
/* parent closes child ends of pipes */
if (outpipe[WRITE_END] > 0)
close(outpipe[WRITE_END]);
if (errpipe[WRITE_END] > 0)
close(errpipe[WRITE_END]);
/* read child output */
while (outpipe[READ_END] > 0 || errpipe[READ_END] > 0) {
int fdcount;
fd_set readfds;
FD_ZERO(&readfds);
if (outpipe[READ_END] > 0)
FD_SET(outpipe[READ_END], &readfds);
if (errpipe[READ_END] > 0)
FD_SET(errpipe[READ_END], &readfds);
fdcount = select(MAX(outpipe[READ_END], errpipe[READ_END])+1, &readfds, NULL, NULL, NULL);
if (fdcount < 0) {
if (errno == EINTR)
continue;
err = -1;
break;
}
/* get stdout */
if (outpipe[READ_END] > 0 && FD_ISSET(outpipe[READ_END], &readfds)) {
char inbuf[1024];
char *pos;
char *line;
count = read(outpipe[READ_END], inbuf, sizeof(inbuf)-1);
if (count <= 0) {
close(outpipe[READ_END]);
outpipe[READ_END] = -1;
if (count < 0) {
err(udev, "stdin read failed: %m\n");
err = -1;
}
continue;
}
inbuf[count] = '\0';
/* store result for rule processing */
if (result) {
if (respos + count < ressize) {
memcpy(&result[respos], inbuf, count);
respos += count;
} else {
err(udev, "ressize %ld too short\n", (long)ressize);
err = -1;
}
}
pos = inbuf;
while ((line = strsep(&pos, "\n")))
if (pos || line[0] != '\0')
info(udev, "'%s' (stdout) '%s'\n", argv[0], line);
}
/* get stderr */
if (errpipe[READ_END] > 0 && FD_ISSET(errpipe[READ_END], &readfds)) {
char errbuf[1024];
char *pos;
char *line;
count = read(errpipe[READ_END], errbuf, sizeof(errbuf)-1);
if (count <= 0) {
close(errpipe[READ_END]);
errpipe[READ_END] = -1;
if (count < 0)
err(udev, "stderr read failed: %m\n");
continue;
}
errbuf[count] = '\0';
pos = errbuf;
while ((line = strsep(&pos, "\n")))
if (pos || line[0] != '\0')
info(udev, "'%s' (stderr) '%s'\n", argv[0], line);
}
}
if (outpipe[READ_END] > 0)
close(outpipe[READ_END]);
if (errpipe[READ_END] > 0)
close(errpipe[READ_END]);
/* return the childs stdout string */
if (result) {
result[respos] = '\0';
dbg(udev, "result='%s'\n", result);
if (reslen)
*reslen = respos;
}
}
waitpid(pid, &status, 0);
if (WIFEXITED(status)) {
info(udev, "'%s' returned with exitcode %i\n", command, WEXITSTATUS(status));
if (WEXITSTATUS(status) != 0)
err = -1;
} else {
err(udev, "'%s' unexpected exit with status 0x%04x\n", command, status);
err = -1;
}
}
return err;
}
View Git Blame Copy Permalink