hush/libbb/xfuncs_printf.c
Ryan Mallon 5906a5c26c libbb: Add xsetegid(), xseteuid(), xopen_as_uid_gid() functions
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2013-10-08 14:52:49 +02:00

651 lines
15 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
* Copyright (C) 2006 Rob Landley
* Copyright (C) 2006 Denys Vlasenko
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
/* We need to have separate xfuncs.c and xfuncs_printf.c because
* with current linkers, even with section garbage collection,
* if *.o module references any of XXXprintf functions, you pull in
* entire printf machinery. Even if you do not use the function
* which uses XXXprintf.
*
* xfuncs.c contains functions (not necessarily xfuncs)
* which do not pull in printf, directly or indirectly.
* xfunc_printf.c contains those which do.
*/
#include "libbb.h"
/* All the functions starting with "x" call bb_error_msg_and_die() if they
* fail, so callers never need to check for errors. If it returned, it
* succeeded. */
#ifndef DMALLOC
/* dmalloc provides variants of these that do abort() on failure.
* Since dmalloc's prototypes overwrite the impls here as they are
* included after these prototypes in libbb.h, all is well.
*/
// Warn if we can't allocate size bytes of memory.
void* FAST_FUNC malloc_or_warn(size_t size)
{
void *ptr = malloc(size);
if (ptr == NULL && size != 0)
bb_error_msg(bb_msg_memory_exhausted);
return ptr;
}
// Die if we can't allocate size bytes of memory.
void* FAST_FUNC xmalloc(size_t size)
{
void *ptr = malloc(size);
if (ptr == NULL && size != 0)
bb_error_msg_and_die(bb_msg_memory_exhausted);
return ptr;
}
// Die if we can't resize previously allocated memory. (This returns a pointer
// to the new memory, which may or may not be the same as the old memory.
// It'll copy the contents to a new chunk and free the old one if necessary.)
void* FAST_FUNC 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;
}
#endif /* DMALLOC */
// Die if we can't allocate and zero size bytes of memory.
void* FAST_FUNC xzalloc(size_t size)
{
void *ptr = xmalloc(size);
memset(ptr, 0, size);
return ptr;
}
// Die if we can't copy a string to freshly allocated memory.
char* FAST_FUNC xstrdup(const char *s)
{
char *t;
if (s == NULL)
return NULL;
t = strdup(s);
if (t == NULL)
bb_error_msg_and_die(bb_msg_memory_exhausted);
return t;
}
// Die if we can't allocate n+1 bytes (space for the null terminator) and copy
// the (possibly truncated to length n) string into it.
char* FAST_FUNC xstrndup(const char *s, int n)
{
int m;
char *t;
if (ENABLE_DEBUG && s == NULL)
bb_error_msg_and_die("xstrndup bug");
/* We can just xmalloc(n+1) and strncpy into it, */
/* but think about xstrndup("abc", 10000) wastage! */
m = n;
t = (char*) s;
while (m) {
if (!*t) break;
m--;
t++;
}
n -= m;
t = xmalloc(n + 1);
t[n] = '\0';
return memcpy(t, s, n);
}
// Die if we can't open a file and return a FILE* to it.
// Notice we haven't got xfread(), This is for use with fscanf() and friends.
FILE* FAST_FUNC xfopen(const char *path, const char *mode)
{
FILE *fp = fopen(path, mode);
if (fp == NULL)
bb_perror_msg_and_die("can't open '%s'", path);
return fp;
}
// Die if we can't open a file and return a fd.
int FAST_FUNC xopen3(const char *pathname, int flags, int mode)
{
int ret;
ret = open(pathname, flags, mode);
if (ret < 0) {
bb_perror_msg_and_die("can't open '%s'", pathname);
}
return ret;
}
// Die if we can't open a file and return a fd.
int FAST_FUNC xopen(const char *pathname, int flags)
{
return xopen3(pathname, flags, 0666);
}
// Warn if we can't open a file and return a fd.
int FAST_FUNC open3_or_warn(const char *pathname, int flags, int mode)
{
int ret;
ret = open(pathname, flags, mode);
if (ret < 0) {
bb_perror_msg("can't open '%s'", pathname);
}
return ret;
}
// Warn if we can't open a file and return a fd.
int FAST_FUNC open_or_warn(const char *pathname, int flags)
{
return open3_or_warn(pathname, flags, 0666);
}
/* Die if we can't open an existing file readonly with O_NONBLOCK
* and return the fd.
* Note that for ioctl O_RDONLY is sufficient.
*/
int FAST_FUNC xopen_nonblocking(const char *pathname)
{
return xopen(pathname, O_RDONLY | O_NONBLOCK);
}
int FAST_FUNC xopen_as_uid_gid(const char *pathname, int flags, uid_t u, gid_t g)
{
int fd;
uid_t old_euid = geteuid();
gid_t old_egid = getegid();
xsetegid(g);
xseteuid(u);
fd = xopen(pathname, flags);
xseteuid(old_euid);
xsetegid(old_egid);
return fd;
}
void FAST_FUNC xunlink(const char *pathname)
{
if (unlink(pathname))
bb_perror_msg_and_die("can't remove file '%s'", pathname);
}
void FAST_FUNC xrename(const char *oldpath, const char *newpath)
{
if (rename(oldpath, newpath))
bb_perror_msg_and_die("can't move '%s' to '%s'", oldpath, newpath);
}
int FAST_FUNC rename_or_warn(const char *oldpath, const char *newpath)
{
int n = rename(oldpath, newpath);
if (n)
bb_perror_msg("can't move '%s' to '%s'", oldpath, newpath);
return n;
}
void FAST_FUNC xpipe(int filedes[2])
{
if (pipe(filedes))
bb_perror_msg_and_die("can't create pipe");
}
void FAST_FUNC xdup2(int from, int to)
{
if (dup2(from, to) != to)
bb_perror_msg_and_die("can't duplicate file descriptor");
}
// "Renumber" opened fd
void FAST_FUNC xmove_fd(int from, int to)
{
if (from == to)
return;
xdup2(from, to);
close(from);
}
// Die with an error message if we can't write the entire buffer.
void FAST_FUNC xwrite(int fd, const void *buf, size_t count)
{
if (count) {
ssize_t size = full_write(fd, buf, count);
if ((size_t)size != count)
bb_error_msg_and_die("short write");
}
}
void FAST_FUNC xwrite_str(int fd, const char *str)
{
xwrite(fd, str, strlen(str));
}
void FAST_FUNC xclose(int fd)
{
if (close(fd))
bb_perror_msg_and_die("close failed");
}
// Die with an error message if we can't lseek to the right spot.
off_t FAST_FUNC xlseek(int fd, off_t offset, int whence)
{
off_t off = lseek(fd, offset, whence);
if (off == (off_t)-1) {
if (whence == SEEK_SET)
bb_perror_msg_and_die("lseek(%"OFF_FMT"u)", offset);
bb_perror_msg_and_die("lseek");
}
return off;
}
int FAST_FUNC xmkstemp(char *template)
{
int fd = mkstemp(template);
if (fd < 0)
bb_perror_msg_and_die("can't create temp file '%s'", template);
return fd;
}
// Die with supplied filename if this FILE* has ferror set.
void FAST_FUNC die_if_ferror(FILE *fp, const char *fn)
{
if (ferror(fp)) {
/* ferror doesn't set useful errno */
bb_error_msg_and_die("%s: I/O error", fn);
}
}
// Die with an error message if stdout has ferror set.
void FAST_FUNC die_if_ferror_stdout(void)
{
die_if_ferror(stdout, bb_msg_standard_output);
}
int FAST_FUNC fflush_all(void)
{
return fflush(NULL);
}
int FAST_FUNC bb_putchar(int ch)
{
return putchar(ch);
}
/* Die with an error message if we can't copy an entire FILE* to stdout,
* then close that file. */
void FAST_FUNC xprint_and_close_file(FILE *file)
{
fflush_all();
// copyfd outputs error messages for us.
if (bb_copyfd_eof(fileno(file), STDOUT_FILENO) == -1)
xfunc_die();
fclose(file);
}
// Die with an error message if we can't malloc() enough space and do an
// sprintf() into that space.
char* FAST_FUNC xasprintf(const char *format, ...)
{
va_list p;
int r;
char *string_ptr;
va_start(p, format);
r = vasprintf(&string_ptr, format, p);
va_end(p);
if (r < 0)
bb_error_msg_and_die(bb_msg_memory_exhausted);
return string_ptr;
}
void FAST_FUNC xsetenv(const char *key, const char *value)
{
if (setenv(key, value, 1))
bb_error_msg_and_die(bb_msg_memory_exhausted);
}
/* Handles "VAR=VAL" strings, even those which are part of environ
* _right now_
*/
void FAST_FUNC bb_unsetenv(const char *var)
{
char *tp = strchr(var, '=');
if (!tp) {
unsetenv(var);
return;
}
/* In case var was putenv'ed, we can't replace '='
* with NUL and unsetenv(var) - it won't work,
* env is modified by the replacement, unsetenv
* sees "VAR" instead of "VAR=VAL" and does not remove it!
* horror :( */
tp = xstrndup(var, tp - var);
unsetenv(tp);
free(tp);
}
void FAST_FUNC bb_unsetenv_and_free(char *var)
{
bb_unsetenv(var);
free(var);
}
// Die with an error message if we can't set gid. (Because resource limits may
// limit this user to a given number of processes, and if that fills up the
// setgid() will fail and we'll _still_be_root_, which is bad.)
void FAST_FUNC xsetgid(gid_t gid)
{
if (setgid(gid)) bb_perror_msg_and_die("setgid");
}
// Die with an error message if we can't set uid. (See xsetgid() for why.)
void FAST_FUNC xsetuid(uid_t uid)
{
if (setuid(uid)) bb_perror_msg_and_die("setuid");
}
void FAST_FUNC xsetegid(gid_t egid)
{
if (setegid(egid)) bb_perror_msg_and_die("setegid");
}
void FAST_FUNC xseteuid(uid_t euid)
{
if (seteuid(euid)) bb_perror_msg_and_die("seteuid");
}
// Die if we can't chdir to a new path.
void FAST_FUNC xchdir(const char *path)
{
if (chdir(path))
bb_perror_msg_and_die("can't change directory to '%s'", path);
}
void FAST_FUNC xchroot(const char *path)
{
if (chroot(path))
bb_perror_msg_and_die("can't change root directory to '%s'", path);
xchdir("/");
}
// Print a warning message if opendir() fails, but don't die.
DIR* FAST_FUNC warn_opendir(const char *path)
{
DIR *dp;
dp = opendir(path);
if (!dp)
bb_perror_msg("can't open '%s'", path);
return dp;
}
// Die with an error message if opendir() fails.
DIR* FAST_FUNC xopendir(const char *path)
{
DIR *dp;
dp = opendir(path);
if (!dp)
bb_perror_msg_and_die("can't open '%s'", path);
return dp;
}
// Die with an error message if we can't open a new socket.
int FAST_FUNC xsocket(int domain, int type, int protocol)
{
int r = socket(domain, type, protocol);
if (r < 0) {
/* Hijack vaguely related config option */
#if ENABLE_VERBOSE_RESOLUTION_ERRORS
const char *s = "INET";
# ifdef AF_PACKET
if (domain == AF_PACKET) s = "PACKET";
# endif
# ifdef AF_NETLINK
if (domain == AF_NETLINK) s = "NETLINK";
# endif
IF_FEATURE_IPV6(if (domain == AF_INET6) s = "INET6";)
bb_perror_msg_and_die("socket(AF_%s,%d,%d)", s, type, protocol);
#else
bb_perror_msg_and_die("socket");
#endif
}
return r;
}
// Die with an error message if we can't bind a socket to an address.
void FAST_FUNC xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
{
if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
}
// Die with an error message if we can't listen for connections on a socket.
void FAST_FUNC xlisten(int s, int backlog)
{
if (listen(s, backlog)) bb_perror_msg_and_die("listen");
}
/* Die with an error message if sendto failed.
* Return bytes sent otherwise */
ssize_t FAST_FUNC xsendto(int s, const void *buf, size_t len, const struct sockaddr *to,
socklen_t tolen)
{
ssize_t ret = sendto(s, buf, len, 0, to, tolen);
if (ret < 0) {
if (ENABLE_FEATURE_CLEAN_UP)
close(s);
bb_perror_msg_and_die("sendto");
}
return ret;
}
// xstat() - a stat() which dies on failure with meaningful error message
void FAST_FUNC xstat(const char *name, struct stat *stat_buf)
{
if (stat(name, stat_buf))
bb_perror_msg_and_die("can't stat '%s'", name);
}
void FAST_FUNC xfstat(int fd, struct stat *stat_buf, const char *errmsg)
{
/* errmsg is usually a file name, but not always:
* xfstat may be called in a spot where file name is no longer
* available, and caller may give e.g. "can't stat input file" string.
*/
if (fstat(fd, stat_buf))
bb_simple_perror_msg_and_die(errmsg);
}
// selinux_or_die() - die if SELinux is disabled.
void FAST_FUNC selinux_or_die(void)
{
#if ENABLE_SELINUX
int rc = is_selinux_enabled();
if (rc == 0) {
bb_error_msg_and_die("SELinux is disabled");
} else if (rc < 0) {
bb_error_msg_and_die("is_selinux_enabled() failed");
}
#else
bb_error_msg_and_die("SELinux support is disabled");
#endif
}
int FAST_FUNC ioctl_or_perror_and_die(int fd, unsigned request, void *argp, const char *fmt,...)
{
int ret;
va_list p;
ret = ioctl(fd, request, argp);
if (ret < 0) {
va_start(p, fmt);
bb_verror_msg(fmt, p, strerror(errno));
/* xfunc_die can actually longjmp, so be nice */
va_end(p);
xfunc_die();
}
return ret;
}
int FAST_FUNC ioctl_or_perror(int fd, unsigned request, void *argp, const char *fmt,...)
{
va_list p;
int ret = ioctl(fd, request, argp);
if (ret < 0) {
va_start(p, fmt);
bb_verror_msg(fmt, p, strerror(errno));
va_end(p);
}
return ret;
}
#if ENABLE_IOCTL_HEX2STR_ERROR
int FAST_FUNC bb_ioctl_or_warn(int fd, unsigned request, void *argp, const char *ioctl_name)
{
int ret;
ret = ioctl(fd, request, argp);
if (ret < 0)
bb_simple_perror_msg(ioctl_name);
return ret;
}
int FAST_FUNC bb_xioctl(int fd, unsigned request, void *argp, const char *ioctl_name)
{
int ret;
ret = ioctl(fd, request, argp);
if (ret < 0)
bb_simple_perror_msg_and_die(ioctl_name);
return ret;
}
#else
int FAST_FUNC bb_ioctl_or_warn(int fd, unsigned request, void *argp)
{
int ret;
ret = ioctl(fd, request, argp);
if (ret < 0)
bb_perror_msg("ioctl %#x failed", request);
return ret;
}
int FAST_FUNC bb_xioctl(int fd, unsigned request, void *argp)
{
int ret;
ret = ioctl(fd, request, argp);
if (ret < 0)
bb_perror_msg_and_die("ioctl %#x failed", request);
return ret;
}
#endif
char* FAST_FUNC xmalloc_ttyname(int fd)
{
char buf[128];
int r = ttyname_r(fd, buf, sizeof(buf) - 1);
if (r)
return NULL;
return xstrdup(buf);
}
void FAST_FUNC generate_uuid(uint8_t *buf)
{
/* http://www.ietf.org/rfc/rfc4122.txt
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | time_low |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | time_mid | time_hi_and_version |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |clk_seq_and_variant | node (0-1) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | node (2-5) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* IOW, uuid has this layout:
* uint32_t time_low (big endian)
* uint16_t time_mid (big endian)
* uint16_t time_hi_and_version (big endian)
* version is a 4-bit field:
* 1 Time-based
* 2 DCE Security, with embedded POSIX UIDs
* 3 Name-based (MD5)
* 4 Randomly generated
* 5 Name-based (SHA-1)
* uint16_t clk_seq_and_variant (big endian)
* variant is a 3-bit field:
* 0xx Reserved, NCS backward compatibility
* 10x The variant specified in rfc4122
* 110 Reserved, Microsoft backward compatibility
* 111 Reserved for future definition
* uint8_t node[6]
*
* For version 4, these bits are set/cleared:
* time_hi_and_version & 0x0fff | 0x4000
* clk_seq_and_variant & 0x3fff | 0x8000
*/
pid_t pid;
int i;
i = open("/dev/urandom", O_RDONLY);
if (i >= 0) {
read(i, buf, 16);
close(i);
}
/* Paranoia. /dev/urandom may be missing.
* rand() is guaranteed to generate at least [0, 2^15) range,
* but lowest bits in some libc are not so "random". */
srand(monotonic_us()); /* pulls in printf */
pid = getpid();
while (1) {
for (i = 0; i < 16; i++)
buf[i] ^= rand() >> 5;
if (pid == 0)
break;
srand(pid);
pid = 0;
}
/* version = 4 */
buf[4 + 2 ] = (buf[4 + 2 ] & 0x0f) | 0x40;
/* variant = 10x */
buf[4 + 2 + 2] = (buf[4 + 2 + 2] & 0x3f) | 0x80;
}
#if BB_MMU
pid_t FAST_FUNC xfork(void)
{
pid_t pid;
pid = fork();
if (pid < 0) /* wtf? */
bb_perror_msg_and_die("vfork"+1);
return pid;
}
#endif