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/* Locating a program in a given path.
Copyright (C) 2001-2004, 2006-2023 Free Software Foundation, Inc.
Written by Bruno Haible <[email protected]>, 2001, 2019.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "findprog.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include "filename.h"
#include "concat-filename.h"
#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
/* Native Windows, OS/2, DOS */
# define NATIVE_SLASH '\\'
#else
/* Unix */
# define NATIVE_SLASH '/'
#endif
/* Separator in PATH like lists of pathnames. */
#if (defined _WIN32 && !defined __CYGWIN__) || defined __EMX__ || defined __DJGPP__
/* Native Windows, OS/2, DOS */
# define PATH_SEPARATOR ';'
#else
/* Unix */
# define PATH_SEPARATOR ':'
#endif
/* The list of suffixes that the execlp/execvp function tries when searching
for the program. */
static const char * const suffixes[] =
{
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
"", ".com", ".exe", ".bat", ".cmd"
/* Note: Files without any suffix are not considered executable. */
/* Note: The cmd.exe program does a different lookup: It searches according
to the PATHEXT environment variable.
See <https://stackoverflow.com/questions/7839150/>.
Also, it executes files ending in .bat and .cmd directly without letting
the kernel interpret the program file. */
#elif defined __CYGWIN__
"", ".exe", ".com"
#elif defined __EMX__
"", ".exe"
#elif defined __DJGPP__
"", ".com", ".exe", ".bat"
#else /* Unix */
""
#endif
};
const char *
find_in_given_path (const char *progname, const char *path,
const char *directory, bool optimize_for_exec)
{
{
bool has_slash = false;
{
const char *p;
for (p = progname; *p != '\0'; p++)
if (ISSLASH (*p))
{
has_slash = true;
break;
}
}
if (has_slash)
{
/* If progname contains a slash, it is either absolute or relative to
the current directory. PATH is not used. */
if (optimize_for_exec)
/* The execl/execv/execlp/execvp functions will try the various
suffixes anyway and fail if no executable is found. */
return progname;
else
{
/* Try the various suffixes and see whether one of the files
with such a suffix is actually executable. */
int failure_errno;
size_t i;
const char *directory_as_prefix =
(directory != NULL && IS_RELATIVE_FILE_NAME (progname)
? directory
: "");
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
const char *progbasename;
{
const char *p;
progbasename = progname;
for (p = progname; *p != '\0'; p++)
if (ISSLASH (*p))
progbasename = p + 1;
}
bool progbasename_has_dot = (strchr (progbasename, '.') != NULL);
#endif
/* Try all platform-dependent suffixes. */
failure_errno = ENOENT;
for (i = 0; i < sizeof (suffixes) / sizeof (suffixes[0]); i++)
{
const char *suffix = suffixes[i];
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
/* File names without a '.' are not considered executable, and
for file names with a '.' no additional suffix is tried. */
if ((*suffix != '\0') != progbasename_has_dot)
#endif
{
/* Concatenate directory_as_prefix, progname, suffix. */
char *progpathname =
concatenated_filename (directory_as_prefix, progname,
suffix);
if (progpathname == NULL)
return NULL; /* errno is set here */
/* On systems which have the eaccess() system call, let's
use it. On other systems, let's hope that this program
is not installed setuid or setgid, so that it is ok to
call access() despite its design flaw. */
if (eaccess (progpathname, X_OK) == 0)
{
/* Check that the progpathname does not point to a
directory. */
struct stat statbuf;
if (stat (progpathname, &statbuf) >= 0)
{
if (! S_ISDIR (statbuf.st_mode))
{
/* Found! */
if (strcmp (progpathname, progname) == 0)
{
free (progpathname);
return progname;
}
else
return progpathname;
}
errno = EACCES;
}
}
if (errno != ENOENT)
failure_errno = errno;
free (progpathname);
}
}
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
if (failure_errno == ENOENT && !progbasename_has_dot)
{
/* In the loop above, we skipped suffix = "". Do this loop
round now, merely to provide a better errno than ENOENT. */
char *progpathname =
concatenated_filename (directory_as_prefix, progname, "");
if (progpathname == NULL)
return NULL; /* errno is set here */
if (eaccess (progpathname, X_OK) == 0)
{
struct stat statbuf;
if (stat (progpathname, &statbuf) >= 0)
{
if (! S_ISDIR (statbuf.st_mode))
errno = ENOEXEC;
else
errno = EACCES;
}
}
failure_errno = errno;
free (progpathname);
}
#endif
errno = failure_errno;
return NULL;
}
}
}
if (path == NULL)
/* If PATH is not set, the default search path is implementation dependent.
In practice, it is treated like an empty PATH. */
path = "";
{
/* Make a copy, to prepare for destructive modifications. */
char *path_copy = strdup (path);
if (path_copy == NULL)
return NULL; /* errno is set here */
int failure_errno;
char *path_rest;
char *cp;
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
bool progname_has_dot = (strchr (progname, '.') != NULL);
#endif
failure_errno = ENOENT;
for (path_rest = path_copy; ; path_rest = cp + 1)
{
const char *dir;
bool last;
char *dir_as_prefix_to_free;
const char *dir_as_prefix;
size_t i;
/* Extract next directory in PATH. */
dir = path_rest;
for (cp = path_rest; *cp != '\0' && *cp != PATH_SEPARATOR; cp++)
;
last = (*cp == '\0');
*cp = '\0';
/* Empty PATH components designate the current directory. */
if (dir == cp)
dir = ".";
/* Concatenate directory and dir. */
if (directory != NULL && IS_RELATIVE_FILE_NAME (dir))
{
dir_as_prefix_to_free =
concatenated_filename (directory, dir, NULL);
if (dir_as_prefix_to_free == NULL)
{
/* errno is set here. */
failure_errno = errno;
goto failed;
}
dir_as_prefix = dir_as_prefix_to_free;
}
else
{
dir_as_prefix_to_free = NULL;
dir_as_prefix = dir;
}
/* Try all platform-dependent suffixes. */
for (i = 0; i < sizeof (suffixes) / sizeof (suffixes[0]); i++)
{
const char *suffix = suffixes[i];
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
/* File names without a '.' are not considered executable, and
for file names with a '.' no additional suffix is tried. */
if ((*suffix != '\0') != progname_has_dot)
#endif
{
/* Concatenate dir_as_prefix, progname, and suffix. */
char *progpathname =
concatenated_filename (dir_as_prefix, progname, suffix);
if (progpathname == NULL)
{
/* errno is set here. */
failure_errno = errno;
free (dir_as_prefix_to_free);
goto failed;
}
/* On systems which have the eaccess() system call, let's
use it. On other systems, let's hope that this program
is not installed setuid or setgid, so that it is ok to
call access() despite its design flaw. */
if (eaccess (progpathname, X_OK) == 0)
{
/* Check that the progpathname does not point to a
directory. */
struct stat statbuf;
if (stat (progpathname, &statbuf) >= 0)
{
if (! S_ISDIR (statbuf.st_mode))
{
/* Found! */
if (strcmp (progpathname, progname) == 0)
{
free (progpathname);
/* Add the "./" prefix for real, that
concatenated_filename() optimized away.
This avoids a second PATH search when the
caller uses execl/execv/execlp/execvp. */
progpathname =
(char *) malloc (2 + strlen (progname) + 1);
if (progpathname == NULL)
{
/* errno is set here. */
failure_errno = errno;
free (dir_as_prefix_to_free);
goto failed;
}
progpathname[0] = '.';
progpathname[1] = NATIVE_SLASH;
memcpy (progpathname + 2, progname,
strlen (progname) + 1);
}
free (dir_as_prefix_to_free);
free (path_copy);
return progpathname;
}
errno = EACCES;
}
}
if (errno != ENOENT)
failure_errno = errno;
free (progpathname);
}
}
#if defined _WIN32 && !defined __CYGWIN__ /* Native Windows */
if (failure_errno == ENOENT && !progname_has_dot)
{
/* In the loop above, we skipped suffix = "". Do this loop
round now, merely to provide a better errno than ENOENT. */
char *progpathname =
concatenated_filename (dir_as_prefix, progname, "");
if (progpathname == NULL)
{
/* errno is set here. */
failure_errno = errno;
free (dir_as_prefix_to_free);
goto failed;
}
if (eaccess (progpathname, X_OK) == 0)
{
struct stat statbuf;
if (stat (progpathname, &statbuf) >= 0)
{
if (! S_ISDIR (statbuf.st_mode))
errno = ENOEXEC;
else
errno = EACCES;
}
}
failure_errno = errno;
free (progpathname);
}
#endif
free (dir_as_prefix_to_free);
if (last)
break;
}
failed:
/* Not found in PATH. */
free (path_copy);
errno = failure_errno;
return NULL;
}
}
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