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[Bug-gnulib] addition: findprog.h, findprog.c
From: |
Bruno Haible |
Subject: |
[Bug-gnulib] addition: findprog.h, findprog.c |
Date: |
Thu, 10 Apr 2003 17:53:10 +0200 (CEST) |
Hi,
This is the beginning of a series of five modules for executing
programs. fork() and execv() are too low level, posix_spawn() is not
portable enough, pexecute() is not general enough.
The modules (all coming from GNU gettext) are:
findprog - Locating a program in PATH.
wait-process - Waiting for a subprocess to finish.
execute - Creation of autonomous subprocesses.
pipe - Creation of subprocesses, communicating via pipes.
sh-quote - Shell quoting.
The first of these, locating a program in PATH, is used for two
purposes in GNU gettext:
- speeding up multiple consecutive execvp() with the same program,
- testing whether the "grep" found in PATH is the broken one from
Solaris.
Any objections?
Bruno
============================ findprog.h ============================
/* Locating a program in PATH.
Copyright (C) 2001-2002 Free Software Foundation, Inc.
Written by Bruno Haible <address@hidden>, 2001.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/* Look up a program in the PATH.
Attempt to determine the pathname that would be called by execlp/execvp
of PROGNAME. If successful, return a pathname containing a slash
(either absolute or relative to the current directory). Otherwise,
return PROGNAME unmodified. */
extern const char *find_in_path (const char *progname);
============================ findprog.c ============================
/* Locating a program in PATH.
Copyright (C) 2001-2002 Free Software Foundation, Inc.
Written by Bruno Haible <address@hidden>, 2001.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
/* Specification. */
#include "findprog.h"
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include "xalloc.h"
#include "pathname.h"
const char *
find_in_path (const char *progname)
{
#if defined _WIN32 || defined __WIN32__ || defined __EMX__ || defined __DJGPP__
/* Win32, OS/2, DOS */
/* The searching rules with .COM, .EXE, .BAT, .CMD etc. suffixes are
too complicated. Leave it to the OS. */
return progname;
#else
/* Unix */
char *path;
char *dir;
char *cp;
if (strchr (progname, '/') != NULL)
/* If progname contains a slash, it is either absolute or relative to
the current directory. PATH is not used. */
return progname;
path = getenv ("PATH");
if (path == NULL || *path == '\0')
/* If PATH is not set, the default search path is implementation
dependent. */
return progname;
/* Make a copy, to prepare for destructive modifications. */
path = xstrdup (path);
for (dir = path; ; dir = cp + 1)
{
int last;
char *progpathname;
/* Extract next directory in PATH. */
for (cp = dir; *cp != '\0' && *cp != ':'; cp++);
last = (*cp == '\0');
*cp = '\0';
/* Empty PATH components designate the current directory. */
if (dir == cp)
dir = ".";
/* Concatenate dir and progname. */
progpathname = concatenated_pathname (dir, progname, NULL);
/* This program is usually not installed setuid or setgid, therefore
it is ok to call access() despite its design flaw. */
if (access (progpathname, X_OK) == 0)
{
/* Found! */
if (strcmp (progpathname, progname) == 0)
{
free (progpathname);
/* Add the "./" prefix for real, that concatenated_pathname()
optimized away. */
progpathname = xmalloc (2 + strlen (progname) + 1);
progpathname[0] = '.';
progpathname[1] = '/';
memcpy (progpathname + 2, progname, strlen (progname) + 1);
}
free (path);
return progpathname;
}
free (progpathname);
if (last)
break;
}
/* Not found in PATH. An error will be signalled at the first call. */
free (path);
return progname;
#endif
}
- [Bug-gnulib] addition: findprog.h, findprog.c,
Bruno Haible <=