blob: 83f54a0a1a3e09687861b381645334ef71f36441 [file] [log] [blame]
/* xwrap.c - wrappers around existing library functions.
*
* Functions with the x prefix are wrappers that either succeed or kill the
* program with an error message, but never return failure. They usually have
* the same arguments and return value as the function they wrap.
*
* Copyright 2006 Rob Landley <rob@landley.net>
*/
#include "toys.h"
// strcpy and strncat with size checking. Size is the total space in "dest",
// including null terminator. Exit if there's not enough space for the string
// (including space for the null terminator), because silently truncating is
// still broken behavior. (And leaving the string unterminated is INSANE.)
void xstrncpy(char *dest, char *src, size_t size)
{
if (strlen(src)+1 > size) error_exit("'%s' > %ld bytes", src, (long)size);
strcpy(dest, src);
}
void xstrncat(char *dest, char *src, size_t size)
{
long len = strlen(dest);
if (len+strlen(src)+1 > size)
error_exit("'%s%s' > %ld bytes", dest, src, (long)size);
strcpy(dest+len, src);
}
// We replaced exit(), _exit(), and atexit() with xexit(), _xexit(), and
// sigatexit(). This gives _xexit() the option to siglongjmp(toys.rebound, 1)
// instead of exiting, lets xexit() report stdout flush failures to stderr
// and change the exit code to indicate error, lets our toys.exit function
// change happen for signal exit paths and lets us remove the functions
// after we've called them.
void _xexit(void)
{
if (toys.rebound) siglongjmp(*toys.rebound, 1);
_exit(toys.exitval);
}
void xexit(void)
{
// Call toys.xexit functions in reverse order added.
while (toys.xexit) {
// This is typecasting xexit->arg to a function pointer,then calling it.
// Using the invalid signal number 0 lets the signal handlers distinguish
// an actual signal from a regular exit.
((void (*)(int))(toys.xexit->arg))(0);
free(llist_pop(&toys.xexit));
}
if (fflush(NULL) || ferror(stdout))
if (!toys.exitval) perror_msg("write");
_xexit();
}
void *xmmap(void *addr, size_t length, int prot, int flags, int fd, off_t off)
{
void *ret = mmap(addr, length, prot, flags, fd, off);
if (ret == MAP_FAILED) perror_exit("mmap");
return ret;
}
// Die unless we can allocate memory.
void *xmalloc(size_t size)
{
void *ret = malloc(size);
if (!ret) error_exit("xmalloc(%ld)", (long)size);
return ret;
}
// Die unless we can allocate prezeroed memory.
void *xzalloc(size_t size)
{
void *ret = xmalloc(size);
memset(ret, 0, size);
return ret;
}
// Die unless we can change the size of an existing allocation, possibly
// moving it. (Notice different arguments from libc function.)
void *xrealloc(void *ptr, size_t size)
{
ptr = realloc(ptr, size);
if (!ptr) error_exit("xrealloc");
return ptr;
}
// Die unless we can allocate a copy of this many bytes of string.
char *xstrndup(char *s, size_t n)
{
char *ret = strndup(s, ++n);
if (!ret) error_exit("xstrndup");
ret[--n] = 0;
return ret;
}
// Die unless we can allocate a copy of this string.
char *xstrdup(char *s)
{
return xstrndup(s, strlen(s));
}
void *xmemdup(void *s, long len)
{
void *ret = xmalloc(len);
memcpy(ret, s, len);
return ret;
}
// Die unless we can allocate enough space to sprintf() into.
char *xmprintf(char *format, ...)
{
va_list va, va2;
int len;
char *ret;
va_start(va, format);
va_copy(va2, va);
// How long is it?
len = vsnprintf(0, 0, format, va);
len++;
va_end(va);
// Allocate and do the sprintf()
ret = xmalloc(len);
vsnprintf(ret, len, format, va2);
va_end(va2);
return ret;
}
void xprintf(char *format, ...)
{
va_list va;
va_start(va, format);
vprintf(format, va);
va_end(va);
if (fflush(stdout) || ferror(stdout)) perror_exit("write");
}
void xputs(char *s)
{
if (EOF == puts(s) || fflush(stdout) || ferror(stdout)) perror_exit("write");
}
void xputc(char c)
{
if (EOF == fputc(c, stdout) || fflush(stdout) || ferror(stdout))
perror_exit("write");
}
void xflush(void)
{
if (fflush(stdout) || ferror(stdout)) perror_exit("write");;
}
// This is called through the XVFORK macro because parent/child of vfork
// share a stack, so child returning from a function would stomp the return
// address parent would need. Solution: make vfork() an argument so processes
// diverge before function gets called.
pid_t __attribute__((returns_twice)) xvforkwrap(pid_t pid)
{
if (pid == -1) perror_exit("vfork");
// Signal to xexec() and friends that we vforked so can't recurse
toys.stacktop = 0;
return pid;
}
// Die unless we can exec argv[] (or run builtin command). Note that anything
// with a path isn't a builtin, so /bin/sh won't match the builtin sh.
void xexec(char **argv)
{
// Only recurse to builtin when we have multiplexer and !vfork context.
if (CFG_TOYBOX && !CFG_TOYBOX_NORECURSE && toys.stacktop) toy_exec(argv);
execvp(argv[0], argv);
perror_msg("exec %s", argv[0]);
toys.exitval = 127;
if (!CFG_TOYBOX_FORK) _exit(toys.exitval);
xexit();
}
// Spawn child process, capturing stdin/stdout.
// argv[]: command to exec. If null, child re-runs original program with
// toys.stacktop zeroed.
// pipes[2]: stdin, stdout of new process, only allocated if zero on way in,
// pass NULL to skip pipe allocation entirely.
// return: pid of child process
pid_t xpopen_both(char **argv, int *pipes)
{
int cestnepasun[4], pid;
// Make the pipes? Note this won't set either pipe to 0 because if fds are
// allocated in order and if fd0 was free it would go to cestnepasun[0]
if (pipes) {
for (pid = 0; pid < 2; pid++) {
if (pipes[pid] != 0) continue;
if (pipe(cestnepasun+(2*pid))) perror_exit("pipe");
pipes[pid] = cestnepasun[pid+1];
}
}
// Child process.
if (!(pid = CFG_TOYBOX_FORK ? xfork() : XVFORK())) {
// Dance of the stdin/stdout redirection.
if (pipes) {
// if we had no stdin/out, pipe handles could overlap, so test for it
// and free up potentially overlapping pipe handles before reuse
if (pipes[1] != -1) close(cestnepasun[2]);
if (pipes[0] != -1) {
close(cestnepasun[1]);
if (cestnepasun[0]) {
dup2(cestnepasun[0], 0);
close(cestnepasun[0]);
}
}
if (pipes[1] != -1) {
dup2(cestnepasun[3], 1);
dup2(cestnepasun[3], 2);
if (cestnepasun[3] > 2 || !cestnepasun[3]) close(cestnepasun[3]);
}
}
if (argv) xexec(argv);
// In fork() case, force recursion because we know it's us.
if (CFG_TOYBOX_FORK) {
toy_init(toys.which, toys.argv);
toys.stacktop = 0;
toys.which->toy_main();
xexit();
// In vfork() case, exec /proc/self/exe with high bit of first letter set
// to tell main() we reentered.
} else {
char *s = "/proc/self/exe";
// We did a nommu-friendly vfork but must exec to continue.
// setting high bit of argv[0][0] to let new process know
**toys.argv |= 0x80;
execv(s, toys.argv);
perror_msg_raw(s);
_exit(127);
}
}
// Parent process
if (!CFG_TOYBOX_FORK) **toys.argv &= 0x7f;
if (pipes) {
if (pipes[0] != -1) close(cestnepasun[0]);
if (pipes[1] != -1) close(cestnepasun[3]);
}
return pid;
}
// Wait for child process to exit, then return adjusted exit code.
int xwaitpid(pid_t pid)
{
int status;
while (-1 == waitpid(pid, &status, 0) && errno == EINTR);
return WIFEXITED(status) ? WEXITSTATUS(status) : WTERMSIG(status)+127;
}
int xpclose_both(pid_t pid, int *pipes)
{
if (pipes) {
close(pipes[0]);
close(pipes[1]);
}
return xwaitpid(pid);
}
// Wrapper to xpopen with a pipe for just one of stdin/stdout
pid_t xpopen(char **argv, int *pipe, int isstdout)
{
int pipes[2], pid;
pipes[!isstdout] = -1;
pipes[!!isstdout] = 0;
pid = xpopen_both(argv, pipes);
*pipe = pid ? pipes[!!isstdout] : -1;
return pid;
}
int xpclose(pid_t pid, int pipe)
{
close(pipe);
return xpclose_both(pid, 0);
}
// Call xpopen and wait for it to finish, keeping existing stdin/stdout.
int xrun(char **argv)
{
return xpclose_both(xpopen_both(argv, 0), 0);
}
void xaccess(char *path, int flags)
{
if (access(path, flags)) perror_exit("Can't access '%s'", path);
}
// Die unless we can delete a file. (File must exist to be deleted.)
void xunlink(char *path)
{
if (unlink(path)) perror_exit("unlink '%s'", path);
}
// Die unless we can open/create a file, returning file descriptor.
// The meaning of O_CLOEXEC is reversed (it defaults on, pass it to disable)
// and WARN_ONLY tells us not to exit.
int xcreate_stdio(char *path, int flags, int mode)
{
int fd = open(path, (flags^O_CLOEXEC)&~WARN_ONLY, mode);
if (fd == -1) ((mode&WARN_ONLY) ? perror_msg_raw : perror_exit_raw)(path);
return fd;
}
// Die unless we can open a file, returning file descriptor.
int xopen_stdio(char *path, int flags)
{
return xcreate_stdio(path, flags, 0);
}
void xpipe(int *pp)
{
if (pipe(pp)) perror_exit("xpipe");
}
void xclose(int fd)
{
if (close(fd)) perror_exit("xclose");
}
int xdup(int fd)
{
if (fd != -1) {
fd = dup(fd);
if (fd == -1) perror_exit("xdup");
}
return fd;
}
// Move file descriptor above stdin/stdout/stderr, using /dev/null to consume
// old one. (We should never be called with stdin/stdout/stderr closed, but...)
int notstdio(int fd)
{
if (fd<0) return fd;
while (fd<3) {
int fd2 = xdup(fd);
close(fd);
xopen_stdio("/dev/null", O_RDWR);
fd = fd2;
}
return fd;
}
// Create a file but don't return stdin/stdout/stderr
int xcreate(char *path, int flags, int mode)
{
return notstdio(xcreate_stdio(path, flags, mode));
}
// Open a file descriptor NOT in stdin/stdout/stderr
int xopen(char *path, int flags)
{
return notstdio(xopen_stdio(path, flags));
}
// Open read only, treating "-" as a synonym for stdin, defaulting to warn only
int openro(char *path, int flags)
{
if (!strcmp(path, "-")) return 0;
return xopen(path, flags^WARN_ONLY);
}
// Open read only, treating "-" as a synonym for stdin.
int xopenro(char *path)
{
return openro(path, O_RDONLY|WARN_ONLY);
}
FILE *xfdopen(int fd, char *mode)
{
FILE *f = fdopen(fd, mode);
if (!f) perror_exit("xfdopen");
return f;
}
// Die unless we can open/create a file, returning FILE *.
FILE *xfopen(char *path, char *mode)
{
FILE *f = fopen(path, mode);
if (!f) perror_exit("No file %s", path);
return f;
}
// Die if there's an error other than EOF.
size_t xread(int fd, void *buf, size_t len)
{
ssize_t ret = read(fd, buf, len);
if (ret < 0) perror_exit("xread");
return ret;
}
void xreadall(int fd, void *buf, size_t len)
{
if (len != readall(fd, buf, len)) perror_exit("xreadall");
}
// There's no xwriteall(), just xwrite(). When we read, there may or may not
// be more data waiting. When we write, there is data and it had better go
// somewhere.
void xwrite(int fd, void *buf, size_t len)
{
if (len != writeall(fd, buf, len)) perror_exit("xwrite");
}
// Die if lseek fails, probably due to being called on a pipe.
off_t xlseek(int fd, off_t offset, int whence)
{
offset = lseek(fd, offset, whence);
if (offset<0) perror_exit("lseek");
return offset;
}
char *xgetcwd(void)
{
char *buf = getcwd(NULL, 0);
if (!buf) perror_exit("xgetcwd");
return buf;
}
void xstat(char *path, struct stat *st)
{
if(stat(path, st)) perror_exit("Can't stat %s", path);
}
// Cannonicalize path, even to file with one or more missing components at end.
// if exact, require last path component to exist
char *xabspath(char *path, int exact)
{
struct string_list *todo, *done = 0;
int try = 9999, dirfd = open("/", 0);;
char *ret;
// If this isn't an absolute path, start with cwd.
if (*path != '/') {
char *temp = xgetcwd();
splitpath(path, splitpath(temp, &todo));
free(temp);
} else splitpath(path, &todo);
// Iterate through path components
while (todo) {
struct string_list *new = llist_pop(&todo), **tail;
ssize_t len;
if (!try--) {
errno = ELOOP;
goto error;
}
// Removable path componenents.
if (!strcmp(new->str, ".") || !strcmp(new->str, "..")) {
int x = new->str[1];
free(new);
if (x) {
if (done) free(llist_pop(&done));
len = 0;
} else continue;
// Is this a symlink?
} else len = readlinkat(dirfd, new->str, libbuf, sizeof(libbuf));
if (len>4095) goto error;
if (len<1) {
int fd;
char *s = "..";
// For .. just move dirfd
if (len) {
// Not a symlink: add to linked list, move dirfd, fail if error
if ((exact || todo) && errno != EINVAL) goto error;
new->next = done;
done = new;
if (errno == EINVAL && !todo) break;
s = new->str;
}
fd = openat(dirfd, s, 0);
if (fd == -1 && (exact || todo || errno != ENOENT)) goto error;
close(dirfd);
dirfd = fd;
continue;
}
// If this symlink is to an absolute path, discard existing resolved path
libbuf[len] = 0;
if (*libbuf == '/') {
llist_traverse(done, free);
done=0;
close(dirfd);
dirfd = open("/", 0);
}
free(new);
// prepend components of new path. Note symlink to "/" will leave new NULL
tail = splitpath(libbuf, &new);
// symlink to "/" will return null and leave tail alone
if (new) {
*tail = todo;
todo = new;
}
}
close(dirfd);
// At this point done has the path, in reverse order. Reverse list while
// calculating buffer length.
try = 2;
while (done) {
struct string_list *temp = llist_pop(&done);;
if (todo) try++;
try += strlen(temp->str);
temp->next = todo;
todo = temp;
}
// Assemble return buffer
ret = xmalloc(try);
*ret = '/';
ret [try = 1] = 0;
while (todo) {
if (try>1) ret[try++] = '/';
try = stpcpy(ret+try, todo->str) - ret;
free(llist_pop(&todo));
}
return ret;
error:
close(dirfd);
llist_traverse(todo, free);
llist_traverse(done, free);
return NULL;
}
void xchdir(char *path)
{
if (chdir(path)) error_exit("chdir '%s'", path);
}
void xchroot(char *path)
{
if (chroot(path)) error_exit("chroot '%s'", path);
xchdir("/");
}
struct passwd *xgetpwuid(uid_t uid)
{
struct passwd *pwd = getpwuid(uid);
if (!pwd) error_exit("bad uid %ld", (long)uid);
return pwd;
}
struct group *xgetgrgid(gid_t gid)
{
struct group *group = getgrgid(gid);
if (!group) perror_exit("gid %ld", (long)gid);
return group;
}
unsigned xgetuid(char *name)
{
struct passwd *up = getpwnam(name);
char *s = 0;
long uid;
if (up) return up->pw_uid;
uid = estrtol(name, &s, 10);
if (!errno && s && !*s && uid>=0 && uid<=UINT_MAX) return uid;
error_exit("bad user '%s'", name);
}
unsigned xgetgid(char *name)
{
struct group *gr = getgrnam(name);
char *s = 0;
long gid;
if (gr) return gr->gr_gid;
gid = estrtol(name, &s, 10);
if (!errno && s && !*s && gid>=0 && gid<=UINT_MAX) return gid;
error_exit("bad group '%s'", name);
}
struct passwd *xgetpwnam(char *name)
{
struct passwd *up = getpwnam(name);
if (!up) perror_exit("user '%s'", name);
return up;
}
struct group *xgetgrnam(char *name)
{
struct group *gr = getgrnam(name);
if (!gr) perror_exit("group '%s'", name);
return gr;
}
// setuid() can fail (for example, too many processes belonging to that user),
// which opens a security hole if the process continues as the original user.
void xsetuser(struct passwd *pwd)
{
if (initgroups(pwd->pw_name, pwd->pw_gid) || setgid(pwd->pw_uid)
|| setuid(pwd->pw_uid)) perror_exit("xsetuser '%s'", pwd->pw_name);
}
// This can return null (meaning file not found). It just won't return null
// for memory allocation reasons.
char *xreadlink(char *name)
{
int len, size = 0;
char *buf = 0;
// Grow by 64 byte chunks until it's big enough.
for(;;) {
size +=64;
buf = xrealloc(buf, size);
len = readlink(name, buf, size);
if (len<0) {
free(buf);
return 0;
}
if (len<size) {
buf[len]=0;
return buf;
}
}
}
char *xreadfile(char *name, char *buf, off_t len)
{
if (!(buf = readfile(name, buf, len))) perror_exit("Bad '%s'", name);
return buf;
}
// The data argument to ioctl() is actually long, but it's usually used as
// a pointer. If you need to feed in a number, do (void *)(long) typecast.
int xioctl(int fd, int request, void *data)
{
int rc;
errno = 0;
rc = ioctl(fd, request, data);
if (rc == -1 && errno) perror_exit("ioctl %x", request);
return rc;
}
// Open a /var/run/NAME.pid file, dying if we can't write it or if it currently
// exists and is this executable.
void xpidfile(char *name)
{
char pidfile[256], spid[32];
int i, fd;
pid_t pid;
sprintf(pidfile, "/var/run/%s.pid", name);
// Try three times to open the sucker.
for (i=0; i<3; i++) {
fd = open(pidfile, O_CREAT|O_EXCL|O_WRONLY, 0644);
if (fd != -1) break;
// If it already existed, read it. Loop for race condition.
fd = open(pidfile, O_RDONLY);
if (fd == -1) continue;
// Is the old program still there?
spid[xread(fd, spid, sizeof(spid)-1)] = 0;
close(fd);
pid = atoi(spid);
if (pid < 1 || (kill(pid, 0) && errno == ESRCH)) unlink(pidfile);
// An else with more sanity checking might be nice here.
}
if (i == 3) error_exit("xpidfile %s", name);
xwrite(fd, spid, sprintf(spid, "%ld\n", (long)getpid()));
close(fd);
}
// Copy the rest of in to out and close both files.
long long xsendfile(int in, int out)
{
long long total = 0;
long len;
if (in<0) return 0;
for (;;) {
len = xread(in, libbuf, sizeof(libbuf));
if (len<1) break;
xwrite(out, libbuf, len);
total += len;
}
return total;
}
// parse fractional seconds with optional s/m/h/d suffix
long xparsetime(char *arg, long units, long *fraction)
{
double d;
long l;
if (CFG_TOYBOX_FLOAT) d = strtod(arg, &arg);
else l = strtoul(arg, &arg, 10);
// Parse suffix
if (*arg) {
int ismhd[]={1,60,3600,86400}, i = stridx("smhd", *arg);
if (i == -1) error_exit("Unknown suffix '%c'", *arg);
if (CFG_TOYBOX_FLOAT) d *= ismhd[i];
else l *= ismhd[i];
}
if (CFG_TOYBOX_FLOAT) {
l = (long)d;
if (fraction) *fraction = units*(d-l);
} else if (fraction) *fraction = 0;
return l;
}
// Compile a regular expression into a regex_t
void xregcomp(regex_t *preg, char *regex, int cflags)
{
int rc = regcomp(preg, regex, cflags);
if (rc) {
regerror(rc, preg, libbuf, sizeof(libbuf));
error_exit("xregcomp: %s", libbuf);
}
}
char *xtzset(char *new)
{
char *old = getenv("TZ");
if (old) old = xstrdup(old);
if (new ? setenv("TZ", new, 1) : unsetenv("TZ")) perror_exit("setenv");
tzset();
return old;
}
// Set a signal handler
void xsignal(int signal, void *handler)
{
struct sigaction *sa = (void *)libbuf;
memset(sa, 0, sizeof(struct sigaction));
sa->sa_handler = handler;
if (sigaction(signal, sa, 0)) perror_exit("xsignal %d", signal);
}