busybox/libbb/xfuncs.c
Denis Vlasenko d6772501db tar: fix and sanitize handling of long filenames/linknames
(GNU extensions 'K' and 'L').
We correctly handle them when untarring now, but unfortunately
we still don't use them when tarring! That stupid 100 char limit
is still there!
The biggest problem is that we don't support 'pax' tar format.
Linux kernel tarballs are in this format... shame
2006-11-24 17:21:44 +00:00

511 lines
12 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 Denis Vlasenko
*
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
#include "busybox.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.
*/
// Die if we can't allocate size bytes of memory.
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;
}
// 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 *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 *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 * 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 * xstrndup(const char *s, int n)
{
char *t;
if (ENABLE_DEBUG && s == NULL)
bb_error_msg_and_die("xstrndup bug");
/* TODO: think about xstrndup("abc", 10000)!!! */
t = xmalloc(++n);
return safe_strncpy(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 *xfopen(const char *path, const char *mode)
{
FILE *fp;
if ((fp = fopen(path, mode)) == NULL)
bb_perror_msg_and_die("%s", path);
return fp;
}
// Die if we can't open an existing file and return an fd.
int xopen(const char *pathname, int flags)
{
if (ENABLE_DEBUG && (flags & O_CREAT))
bb_error_msg_and_die("xopen() with O_CREAT");
return xopen3(pathname, flags, 0666);
}
// Die if we can't open a new file and return an fd.
int xopen3(const char *pathname, int flags, int mode)
{
int ret;
ret = open(pathname, flags, mode);
if (ret < 0) {
bb_perror_msg_and_die("%s", pathname);
}
return ret;
}
/*
int ndelay_off(int fd)
{
return fcntl(fd,F_SETFL,fcntl(fd,F_GETFL,0) & ~O_NONBLOCK);
}
*/
// Turn on nonblocking I/O on a fd
int ndelay_on(int fd)
{
return fcntl(fd,F_SETFL,fcntl(fd,F_GETFL,0) | O_NONBLOCK);
}
// Die with an error message if we can't write the entire buffer.
void xwrite(int fd, void *buf, size_t count)
{
if (count) {
ssize_t size = full_write(fd, buf, count);
if (size != count)
bb_error_msg_and_die("short write");
}
}
// Die with an error message if we can't lseek to the right spot.
off_t xlseek(int fd, off_t offset, int whence)
{
off_t off = lseek(fd, offset, whence);
if (off == (off_t)-1)
bb_perror_msg_and_die("lseek");
return off;
}
// Die with supplied error message if this FILE * has ferror set.
void die_if_ferror(FILE *fp, const char *fn)
{
if (ferror(fp)) {
bb_error_msg_and_die("%s", fn);
}
}
// Die with an error message if stdout has ferror set.
void die_if_ferror_stdout(void)
{
die_if_ferror(stdout, bb_msg_standard_output);
}
// Die with an error message if we have trouble flushing stdout.
void xfflush_stdout(void)
{
if (fflush(stdout)) {
bb_perror_msg_and_die(bb_msg_standard_output);
}
}
// This does a fork/exec in one call, using vfork(). Return PID of new child,
// -1 for failure. Runs argv[0], searching path if that has no / in it.
pid_t spawn(char **argv)
{
static int failed;
pid_t pid;
void *app = ENABLE_FEATURE_SH_STANDALONE_SHELL ? find_applet_by_name(argv[0]) : 0;
// Be nice to nommu machines.
failed = 0;
pid = vfork();
if (pid < 0) return pid;
if (!pid) {
execvp(app ? CONFIG_BUSYBOX_EXEC_PATH : *argv, argv);
// We're sharing a stack with blocked parent, let parent know we failed
// and then exit to unblock parent (but don't run atexit() stuff, which
// would screw up parent.)
failed = -1;
_exit(0);
}
return failed ? failed : pid;
}
// Die with an error message if we can't spawn a child process.
pid_t xspawn(char **argv)
{
pid_t pid = spawn(argv);
if (pid < 0) bb_perror_msg_and_die("%s", *argv);
return pid;
}
// Wait for the specified child PID to exit, returning child's error return.
int wait4pid(int pid)
{
int status;
if (pid == -1 || waitpid(pid, &status, 0) == -1) return -1;
if (WIFEXITED(status)) return WEXITSTATUS(status);
if (WIFSIGNALED(status)) return WTERMSIG(status);
return 0;
}
void xsetenv(const char *key, const char *value)
{
if (setenv(key, value, 1))
bb_error_msg_and_die(bb_msg_memory_exhausted);
}
// Converts unsigned long long value into compact 4-char
// representation. Examples: "1234", "1.2k", " 27M", "123T"
// Fifth char is always '\0'
void smart_ulltoa5(unsigned long long ul, char buf[5])
{
char *fmt;
char c;
unsigned v,idx = 0;
ul *= 10;
if (ul > 9999*10) { // do not scale if 9999 or less
while (ul >= 10000) {
ul /= 1024;
idx++;
}
}
v = ul; // ullong divisions are expensive, avoid them
fmt = " 123456789";
if (!idx) { // 9999 or less: use 1234 format
c = buf[0] = " 123456789"[v/10000];
if (c!=' ') fmt = "0123456789";
c = buf[1] = fmt[v/1000%10];
if (c!=' ') fmt = "0123456789";
buf[2] = fmt[v/100%10];
buf[3] = "0123456789"[v/10%10];
} else {
if (v>=10*10) { // scaled value is >=10: use 123M format
c = buf[0] = " 123456789"[v/1000];
if (c!=' ') fmt = "0123456789";
buf[1] = fmt[v/100%10];
buf[2] = "0123456789"[v/10%10];
} else { // scaled value is <10: use 1.2M format
buf[0] = "0123456789"[v/10];
buf[1] = '.';
buf[2] = "0123456789"[v%10];
}
// see http://en.wikipedia.org/wiki/Tera
buf[3] = " kMGTPEZY"[idx];
}
buf[4] = '\0';
}
// Convert unsigned integer to ascii, writing into supplied buffer. A
// truncated result is always null terminated (unless buflen is 0), and
// contains the first few digits of the result ala strncpy.
void BUG_sizeof_unsigned_not_4(void);
void utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
unsigned i, out, res;
if (sizeof(unsigned) != 4)
BUG_sizeof_unsigned_not_4();
if (buflen) {
out = 0;
for (i = 1000000000; i; i /= 10) {
res = n / i;
if (res || out || i == 1) {
if (!--buflen) break;
out++;
n -= res*i;
*buf++ = '0' + res;
}
}
*buf = '\0';
}
}
// Convert signed integer to ascii, like utoa_to_buf()
void itoa_to_buf(int n, char *buf, unsigned buflen)
{
if (buflen && n<0) {
n = -n;
*buf++ = '-';
buflen--;
}
utoa_to_buf((unsigned)n, buf, buflen);
}
// The following two functions use a static buffer, so calling either one a
// second time will overwrite previous results.
//
// The largest 32 bit integer is -2 billion plus null terminator, or 12 bytes.
// Int should always be 32 bits on any remotely Unix-like system, see
// http://www.unix.org/whitepapers/64bit.html for the reasons why.
static char local_buf[12];
// Convert unsigned integer to ascii using a static buffer (returned).
char *utoa(unsigned n)
{
utoa_to_buf(n, local_buf, sizeof(local_buf));
return local_buf;
}
// Convert signed integer to ascii using a static buffer (returned).
char *itoa(int n)
{
itoa_to_buf(n, local_buf, sizeof(local_buf));
return local_buf;
}
// 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 xsetgid(gid_t gid)
{
if (setgid(gid)) bb_error_msg_and_die("setgid");
}
// Die with an error message if we can't set uid. (See xsetgid() for why.)
void xsetuid(uid_t uid)
{
if (setuid(uid)) bb_error_msg_and_die("setuid");
}
// Return how long the file at fd is, if there's any way to determine it.
off_t fdlength(int fd)
{
off_t bottom = 0, top = 0, pos;
long size;
// If the ioctl works for this, return it.
if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
// FIXME: explain why lseek(SEEK_END) is not used here!
// If not, do a binary search for the last location we can read. (Some
// block devices don't do BLKGETSIZE right.)
do {
char temp;
pos = bottom + (top - bottom) / 2;
// If we can read from the current location, it's bigger.
if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
if (bottom == top) bottom = top = (top+1) * 2;
else bottom = pos;
// If we can't, it's smaller.
} else {
if (bottom == top) {
if (!top) return 0;
bottom = top/2;
}
else top = pos;
}
} while (bottom + 1 != top);
return pos + 1;
}
// Die with an error message if we can't malloc() enough space and do an
// sprintf() into that space.
char *xasprintf(const char *format, ...)
{
va_list p;
int r;
char *string_ptr;
#if 1
// GNU extension
va_start(p, format);
r = vasprintf(&string_ptr, format, p);
va_end(p);
#else
// Bloat for systems that haven't got the GNU extension.
va_start(p, format);
r = vsnprintf(NULL, 0, format, p);
va_end(p);
string_ptr = xmalloc(r+1);
va_start(p, format);
r = vsnprintf(string_ptr, r+1, format, p);
va_end(p);
#endif
if (r < 0) bb_error_msg_and_die(bb_msg_memory_exhausted);
return string_ptr;
}
// Die with an error message if we can't copy an entire FILE * to stdout, then
// close that file.
void xprint_and_close_file(FILE *file)
{
fflush(stdout);
// copyfd outputs error messages for us.
if (bb_copyfd_eof(fileno(file), 1) == -1)
exit(xfunc_error_retval);
fclose(file);
}
// Die if we can't chdir to a new path.
void xchdir(const char *path)
{
if (chdir(path))
bb_perror_msg_and_die("chdir(%s)", path);
}
// Print a warning message if opendir() fails, but don't die.
DIR *warn_opendir(const char *path)
{
DIR *dp;
if ((dp = opendir(path)) == NULL) {
bb_perror_msg("cannot open '%s'", path);
return NULL;
}
return dp;
}
// Die with an error message if opendir() fails.
DIR *xopendir(const char *path)
{
DIR *dp;
if ((dp = opendir(path)) == NULL)
bb_perror_msg_and_die("cannot open '%s'", path);
return dp;
}
#ifndef BB_NOMMU
// Die with an error message if we can't daemonize.
void xdaemon(int nochdir, int noclose)
{
if (daemon(nochdir, noclose))
bb_perror_msg_and_die("daemon");
}
#endif
// Die with an error message if we can't open a new socket.
int xsocket(int domain, int type, int protocol)
{
int r = socket(domain, type, protocol);
if (r < 0) bb_perror_msg_and_die("socket");
return r;
}
// Die with an error message if we can't bind a socket to an address.
void 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 xlisten(int s, int backlog)
{
if (listen(s, backlog)) bb_perror_msg_and_die("listen");
}
// xstat() - a stat() which dies on failure with meaningful error message
void xstat(char *name, struct stat *stat_buf)
{
if (stat(name, stat_buf))
bb_perror_msg_and_die("can't stat '%s'", name);
}
/* It is perfectly ok to pass in a NULL for either width or for
* height, in which case that value will not be set. */
int get_terminal_width_height(int fd, int *width, int *height)
{
struct winsize win = { 0, 0, 0, 0 };
int ret = ioctl(fd, TIOCGWINSZ, &win);
if (height) {
if (!win.ws_row) {
char *s = getenv("LINES");
if (s) win.ws_row = atoi(s);
}
if (win.ws_row <= 1 || win.ws_row >= 30000)
win.ws_row = 24;
*height = (int) win.ws_row;
}
if (width) {
if (!win.ws_col) {
char *s = getenv("COLUMNS");
if (s) win.ws_col = atoi(s);
}
if (win.ws_col <= 1 || win.ws_col >= 30000)
win.ws_col = 80;
*width = (int) win.ws_col;
}
return ret;
}