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450 lines
11 KiB
C
450 lines
11 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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* Copyright (C) 2006 Rob Landley
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* Copyright (C) 2006 Denis Vlasenko
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*
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* Licensed under GPL version 2, see file LICENSE in this tarball for details.
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*/
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#include "busybox.h"
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/* All the functions starting with "x" call bb_error_msg_and_die() if they
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* fail, so callers never need to check for errors. If it returned, it
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* succeeded. */
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#ifndef DMALLOC
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/* dmalloc provides variants of these that do abort() on failure.
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* Since dmalloc's prototypes overwrite the impls here as they are
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* included after these prototypes in libbb.h, all is well.
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*/
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// Die if we can't allocate size bytes of memory.
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void *xmalloc(size_t size)
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{
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void *ptr = malloc(size);
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if (ptr == NULL && size != 0)
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bb_error_msg_and_die(bb_msg_memory_exhausted);
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return ptr;
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}
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// Die if we can't resize previously allocated memory. (This returns a pointer
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// to the new memory, which may or may not be the same as the old memory.
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// It'll copy the contents to a new chunk and free the old one if necessary.)
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void *xrealloc(void *ptr, size_t size)
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{
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ptr = realloc(ptr, size);
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if (ptr == NULL && size != 0)
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bb_error_msg_and_die(bb_msg_memory_exhausted);
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return ptr;
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}
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#endif /* DMALLOC */
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// Die if we can't allocate and zero size bytes of memory.
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void *xzalloc(size_t size)
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{
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void *ptr = xmalloc(size);
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memset(ptr, 0, size);
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return ptr;
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}
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// Die if we can't copy a string to freshly allocated memory.
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char * xstrdup(const char *s)
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{
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char *t;
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if (s == NULL)
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return NULL;
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t = strdup (s);
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if (t == NULL)
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bb_error_msg_and_die(bb_msg_memory_exhausted);
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return t;
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}
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// Die if we can't allocate n+1 bytes (space for the null terminator) and copy
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// the (possibly truncated to length n) string into it.
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char * xstrndup(const char *s, int n)
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{
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char *t;
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if (ENABLE_DEBUG && s == NULL)
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bb_error_msg_and_die("xstrndup bug");
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t = xmalloc(++n);
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return safe_strncpy(t,s,n);
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}
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// Die if we can't open a file and return a FILE * to it.
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// Notice we haven't got xfread(), This is for use with fscanf() and friends.
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FILE *xfopen(const char *path, const char *mode)
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{
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FILE *fp;
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if ((fp = fopen(path, mode)) == NULL)
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bb_perror_msg_and_die("%s", path);
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return fp;
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}
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// Die if we can't open an existing file and return an fd.
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int xopen(const char *pathname, int flags)
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{
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if (ENABLE_DEBUG && (flags & O_CREAT))
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bb_error_msg_and_die("xopen() with O_CREAT");
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return xopen3(pathname, flags, 0666);
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}
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// Die if we can't open a new file and return an fd.
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int xopen3(const char *pathname, int flags, int mode)
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{
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int ret;
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ret = open(pathname, flags, mode);
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if (ret < 0) {
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bb_perror_msg_and_die("%s", pathname);
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}
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return ret;
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}
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// Die with an error message if we can't write the entire buffer.
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void xwrite(int fd, void *buf, size_t count)
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{
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if (count) {
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ssize_t size = full_write(fd, buf, count);
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if (size != count)
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bb_error_msg_and_die("short write");
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}
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}
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// Die with an error message if we can't lseek to the right spot.
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off_t xlseek(int fd, off_t offset, int whence)
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{
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off_t off = lseek(fd, offset, whence);
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if (off == (off_t)-1)
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bb_perror_msg_and_die("lseek");
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return off;
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}
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// Die with supplied error message if this FILE * has ferror set.
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void die_if_ferror(FILE *fp, const char *fn)
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{
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if (ferror(fp)) {
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bb_error_msg_and_die("%s", fn);
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}
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}
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// Die with an error message if stdout has ferror set.
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void die_if_ferror_stdout(void)
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{
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die_if_ferror(stdout, bb_msg_standard_output);
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}
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// Die with an error message if we have trouble flushing stdout.
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void xfflush_stdout(void)
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{
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if (fflush(stdout)) {
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bb_perror_msg_and_die(bb_msg_standard_output);
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}
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}
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// This does a fork/exec in one call, using vfork(). Return PID of new child,
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// -1 for failure. Runs argv[0], searching path if that has no / in it.
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pid_t spawn(char **argv)
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{
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static int failed;
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pid_t pid;
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void *app = ENABLE_FEATURE_SH_STANDALONE_SHELL ? find_applet_by_name(argv[0]) : 0;
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// Be nice to nommu machines.
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failed = 0;
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pid = vfork();
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if (pid < 0) return pid;
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if (!pid) {
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execvp(app ? CONFIG_BUSYBOX_EXEC_PATH : *argv, argv);
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// We're sharing a stack with blocked parent, let parent know we failed
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// and then exit to unblock parent (but don't run atexit() stuff, which
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// would screw up parent.)
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failed = -1;
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_exit(0);
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}
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return failed ? failed : pid;
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}
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// Die with an error message if we can't spawn a child process.
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pid_t xspawn(char **argv)
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{
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pid_t pid = spawn(argv);
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if (pid < 0) bb_perror_msg_and_die("%s", *argv);
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return pid;
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}
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// Wait for the specified child PID to exit, returning child's error return.
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int wait4pid(int pid)
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{
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int status;
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if (pid == -1 || waitpid(pid, &status, 0) == -1) return -1;
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if (WIFEXITED(status)) return WEXITSTATUS(status);
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if (WIFSIGNALED(status)) return WTERMSIG(status);
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return 0;
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}
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void xsetenv(const char *key, const char *value)
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{
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if (setenv(key, value, 1))
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bb_error_msg_and_die(bb_msg_memory_exhausted);
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}
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// Convert unsigned integer to ascii, writing into supplied buffer. A
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// truncated result is always null terminated (unless buflen is 0), and
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// contains the first few digits of the result ala strncpy.
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void utoa_to_buf(unsigned n, char *buf, unsigned buflen)
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{
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int i, out = 0;
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if (buflen) {
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for (i=1000000000; i; i/=10) {
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int res = n/i;
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if ((res || out || i == 1) && --buflen>0) {
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out++;
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n -= res*i;
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*buf++ = '0' + res;
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}
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}
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*buf = 0;
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}
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}
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// Convert signed integer to ascii, like utoa_to_buf()
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void itoa_to_buf(int n, char *buf, unsigned buflen)
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{
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if (buflen && n<0) {
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n = -n;
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*buf++ = '-';
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buflen--;
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}
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utoa_to_buf((unsigned)n, buf, buflen);
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}
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// The following two functions use a static buffer, so calling either one a
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// second time will overwrite previous results.
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//
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// The largest 32 bit integer is -2 billion plus null terminator, or 12 bytes.
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// Int should always be 32 bits on any remotely Unix-like system, see
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// http://www.unix.org/whitepapers/64bit.html for the reasons why.
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static char local_buf[12];
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// Convert unsigned integer to ascii using a static buffer (returned).
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char *utoa(unsigned n)
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{
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utoa_to_buf(n, local_buf, sizeof(local_buf));
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return local_buf;
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}
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// Convert signed integer to ascii using a static buffer (returned).
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char *itoa(int n)
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{
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itoa_to_buf(n, local_buf, sizeof(local_buf));
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return local_buf;
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}
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// Die with an error message if we can't set gid. (Because resource limits may
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// limit this user to a given number of processes, and if that fills up the
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// setgid() will fail and we'll _still_be_root_, which is bad.)
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void xsetgid(gid_t gid)
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{
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if (setgid(gid)) bb_error_msg_and_die("setgid");
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}
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// Die with an error message if we can't set uid. (See xsetgid() for why.)
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void xsetuid(uid_t uid)
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{
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if (setuid(uid)) bb_error_msg_and_die("setuid");
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}
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// Return how long the file at fd is, if there's any way to determine it.
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off_t fdlength(int fd)
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{
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off_t bottom = 0, top = 0, pos;
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long size;
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// If the ioctl works for this, return it.
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if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;
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// FIXME: explain why lseek(SEEK_END) is not used here!
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// If not, do a binary search for the last location we can read. (Some
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// block devices don't do BLKGETSIZE right.)
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do {
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char temp;
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pos = bottom + (top - bottom) / 2;
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// If we can read from the current location, it's bigger.
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if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
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if (bottom == top) bottom = top = (top+1) * 2;
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else bottom = pos;
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// If we can't, it's smaller.
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} else {
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if (bottom == top) {
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if (!top) return 0;
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bottom = top/2;
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}
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else top = pos;
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}
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} while (bottom + 1 != top);
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return pos + 1;
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}
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// Die with an error message if we can't malloc() enough space and do an
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// sprintf() into that space.
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char *xasprintf(const char *format, ...)
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{
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va_list p;
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int r;
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char *string_ptr;
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#if 1
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// GNU extension
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va_start(p, format);
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r = vasprintf(&string_ptr, format, p);
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va_end(p);
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#else
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// Bloat for systems that haven't got the GNU extension.
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va_start(p, format);
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r = vsnprintf(NULL, 0, format, p);
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va_end(p);
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string_ptr = xmalloc(r+1);
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va_start(p, format);
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r = vsnprintf(string_ptr, r+1, format, p);
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va_end(p);
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#endif
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if (r < 0) bb_error_msg_and_die(bb_msg_memory_exhausted);
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return string_ptr;
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}
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// Die with an error message if we can't copy an entire FILE * to stdout, then
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// close that file.
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void xprint_and_close_file(FILE *file)
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{
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fflush(stdout);
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// copyfd outputs error messages for us.
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if (bb_copyfd_eof(fileno(file), 1) == -1)
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exit(xfunc_error_retval);
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fclose(file);
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}
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// Die if we can't chdir to a new path.
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void xchdir(const char *path)
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{
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if (chdir(path))
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bb_perror_msg_and_die("chdir(%s)", path);
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}
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// Print a warning message if opendir() fails, but don't die.
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DIR *warn_opendir(const char *path)
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{
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DIR *dp;
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if ((dp = opendir(path)) == NULL) {
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bb_perror_msg("unable to open `%s'", path);
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return NULL;
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}
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return dp;
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}
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// Die with an error message if opendir() fails.
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DIR *xopendir(const char *path)
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{
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DIR *dp;
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if ((dp = opendir(path)) == NULL)
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bb_perror_msg_and_die("unable to open `%s'", path);
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return dp;
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}
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#ifndef BB_NOMMU
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// Die with an error message if we can't daemonize.
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void xdaemon(int nochdir, int noclose)
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{
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if (daemon(nochdir, noclose))
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bb_perror_msg_and_die("daemon");
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}
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#endif
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// Die with an error message if we can't open a new socket.
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int xsocket(int domain, int type, int protocol)
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{
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int r = socket(domain, type, protocol);
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if (r < 0) bb_perror_msg_and_die("socket");
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return r;
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}
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// Die with an error message if we can't bind a socket to an address.
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void xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
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{
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if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
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}
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// Die with an error message if we can't listen for connections on a socket.
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void xlisten(int s, int backlog)
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{
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if (listen(s, backlog)) bb_perror_msg_and_die("listen");
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}
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// xstat() - a stat() which dies on failure with meaningful error message
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void xstat(char *name, struct stat *stat_buf)
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{
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if (stat(name, stat_buf))
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bb_perror_msg_and_die("can't stat '%s'", name);
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}
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/* It is perfectly ok to pass in a NULL for either width or for
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* height, in which case that value will not be set. */
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int get_terminal_width_height(int fd, int *width, int *height)
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{
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struct winsize win = { 0, 0, 0, 0 };
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int ret = ioctl(fd, TIOCGWINSZ, &win);
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if (height) {
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if (!win.ws_row) {
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char *s = getenv("LINES");
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if (s) win.ws_row = atoi(s);
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}
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if (win.ws_row <= 1 || win.ws_row >= 30000)
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win.ws_row = 24;
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*height = (int) win.ws_row;
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}
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if (width) {
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if (!win.ws_col) {
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char *s = getenv("COLUMNS");
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if (s) win.ws_col = atoi(s);
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}
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if (win.ws_col <= 1 || win.ws_col >= 30000)
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win.ws_col = 80;
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*width = (int) win.ws_col;
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}
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return ret;
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}
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