busybox/coreutils/pwd.c

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/* vi: set sw=4 ts=4: */
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/*
* Mini pwd implementation for busybox
*
* Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
//usage:#define pwd_trivial_usage
//usage: ""
//usage:#define pwd_full_usage "\n\n"
//usage: "Print the full filename of the current working directory"
//usage:
//usage:#define pwd_example_usage
//usage: "$ pwd\n"
//usage: "/root\n"
#include "libbb.h"
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/* This is a NOFORK applet. Be very careful! */
static int logical_getcwd(void)
{
struct stat st1;
struct stat st2;
char *wd;
char *p;
wd = getenv("PWD");
if (!wd || wd[0] != '/')
return 0;
p = wd;
while (*p) {
/* doing strstr(p, "/.") by hand is smaller and faster... */
if (*p++ != '/')
continue;
if (*p != '.')
continue;
/* we found "/.", skip to next char */
p++;
if (*p == '.')
p++; /* we found "/.." */
if (*p == '\0' || *p == '/')
return 0; /* "/./" or "/../" component: bad */
}
if (stat(wd, &st1) != 0)
return 0;
if (stat(".", &st2) != 0)
return 0;
if (st1.st_ino != st2.st_ino)
return 0;
if (st1.st_dev != st2.st_dev)
return 0;
puts(wd);
return 1;
}
int pwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int pwd_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
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{
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char *buf;
if (ENABLE_DESKTOP) {
/* TODO: assume -L if $POSIXLY_CORRECT? (coreutils does that)
* Rationale:
* POSIX requires a default of -L, but most scripts expect -P
*/
unsigned opt = getopt32(argv, "LP");
if ((opt & 1) && logical_getcwd())
return fflush_all();
}
buf = xrealloc_getcwd_or_warn(NULL);
if (buf) {
puts(buf);
free(buf);
return fflush_all();
}
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return EXIT_FAILURE;
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}