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82 lines
2.4 KiB
C
82 lines
2.4 KiB
C
/* Find path of executable.
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Copyright (C) 1998-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/param.h>
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#include <ldsodefs.h>
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#include <sysdep.h>
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#include <dl-dst.h>
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/* On Linux >= 2.1 systems which have the dcache implementation we can get
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the path of the application from the /proc/self/exe symlink. Try this
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first and fall back on the generic method if necessary. */
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const char *
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_dl_get_origin (void)
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{
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char linkval[PATH_MAX];
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char *result;
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int len;
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INTERNAL_SYSCALL_DECL (err);
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len = INTERNAL_SYSCALL (readlinkat, err, 4, AT_FDCWD, "/proc/self/exe",
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linkval, sizeof (linkval));
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if (! INTERNAL_SYSCALL_ERROR_P (len, err) && len > 0 && linkval[0] != '[')
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{
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/* We can use this value. */
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assert (linkval[0] == '/');
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while (len > 1 && linkval[len - 1] != '/')
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--len;
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result = (char *) malloc (len + 1);
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if (result == NULL)
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result = (char *) -1;
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else if (len == 1)
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memcpy (result, "/", 2);
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else
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*((char *) __mempcpy (result, linkval, len - 1)) = '\0';
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}
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else
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{
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result = (char *) -1;
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/* We use the environment variable LD_ORIGIN_PATH. If it is set make
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a copy and strip out trailing slashes. */
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if (GLRO(dl_origin_path) != NULL)
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{
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size_t len = strlen (GLRO(dl_origin_path));
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result = (char *) malloc (len + 1);
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if (result == NULL)
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result = (char *) -1;
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else
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{
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char *cp = __mempcpy (result, GLRO(dl_origin_path), len);
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while (cp > result + 1 && cp[-1] == '/')
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--cp;
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*cp = '\0';
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}
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}
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}
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return result;
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}
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