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mirror of git://git.gnupg.org/gnupg.git synced 2024-10-31 20:08:43 +01:00
gnupg/g10/exec.c
Werner Koch b008274afd Nuked almost all trailing white space.
We better do this once and for all instead of cluttering all future
commits with diffs of trailing white spaces.  In the majority of cases
blank or single lines are affected and thus this change won't disturb
a git blame too much.  For future commits the pre-commit scripts
checks that this won't happen again.
2011-02-04 12:57:53 +01:00

633 lines
14 KiB
C

/* exec.c - generic call-a-program code
* Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
* GnuPG 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG 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, see <http://www.gnu.org/licenses/>.
*/
/*
FIXME: We should replace most code in this module by our
spawn implementation from common/exechelp.c.
*/
#include <config.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifndef EXEC_TEMPFILE_ONLY
#include <sys/wait.h>
#endif
#ifdef HAVE_DOSISH_SYSTEM
#include <windows.h>
#endif
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include "gpg.h"
#include "options.h"
#include "i18n.h"
#include "iobuf.h"
#include "util.h"
#include "mkdtemp.h" /* From gnulib. */
#include "membuf.h"
#include "exec.h"
#ifdef NO_EXEC
int
exec_write(struct exec_info **info,const char *program,
const char *args_in,const char *name,int writeonly,int binary)
{
log_error(_("no remote program execution supported\n"));
return G10ERR_GENERAL;
}
int
exec_read(struct exec_info *info) { return G10ERR_GENERAL; }
int
exec_finish(struct exec_info *info) { return G10ERR_GENERAL; }
int
set_exec_path(const char *path) { return G10ERR_GENERAL; }
#else /* ! NO_EXEC */
#if defined (_WIN32)
/* This is a nicer system() for windows that waits for programs to
return before returning control to the caller. I hate helpful
computers. */
static int
w32_system(const char *command)
{
#ifdef HAVE_W32CE_SYSTEM
#warning Change this code to use common/exechelp.c
#else
PROCESS_INFORMATION pi;
STARTUPINFO si;
char *string;
/* We must use a copy of the command as CreateProcess modifies this
argument. */
string=xstrdup(command);
memset(&pi,0,sizeof(pi));
memset(&si,0,sizeof(si));
si.cb=sizeof(si);
if(!CreateProcess(NULL,string,NULL,NULL,FALSE,
DETACHED_PROCESS,
NULL,NULL,&si,&pi))
return -1;
/* Wait for the child to exit */
WaitForSingleObject(pi.hProcess,INFINITE);
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
xfree(string);
return 0;
#endif
}
#endif
/* Replaces current $PATH */
int
set_exec_path(const char *path)
{
#ifdef HAVE_W32CE_SYSTEM
#warning Change this code to use common/exechelp.c
#else
char *p;
p=xmalloc(5+strlen(path)+1);
strcpy(p,"PATH=");
strcat(p,path);
if(DBG_EXTPROG)
log_debug("set_exec_path: %s\n",p);
/* Notice that path is never freed. That is intentional due to the
way putenv() works. This leaks a few bytes if we call
set_exec_path multiple times. */
if(putenv(p)!=0)
return G10ERR_GENERAL;
else
return 0;
#endif
}
/* Makes a temp directory and filenames */
static int
make_tempdir(struct exec_info *info)
{
char *tmp=opt.temp_dir,*namein=info->name,*nameout;
if(!namein)
namein=info->flags.binary?"tempin" EXTSEP_S "bin":"tempin" EXTSEP_S "txt";
nameout=info->flags.binary?"tempout" EXTSEP_S "bin":"tempout" EXTSEP_S "txt";
/* Make up the temp dir and files in case we need them */
if(tmp==NULL)
{
#if defined (_WIN32)
int err;
tmp=xmalloc(MAX_PATH+2);
err=GetTempPath(MAX_PATH+1,tmp);
if(err==0 || err>MAX_PATH+1)
strcpy(tmp,"c:\\windows\\temp");
else
{
int len=strlen(tmp);
/* GetTempPath may return with \ on the end */
while(len>0 && tmp[len-1]=='\\')
{
tmp[len-1]='\0';
len--;
}
}
#else /* More unixish systems */
tmp=getenv("TMPDIR");
if(tmp==NULL)
{
tmp=getenv("TMP");
if(tmp==NULL)
{
#ifdef __riscos__
tmp="<Wimp$ScrapDir>.GnuPG";
mkdir(tmp,0700); /* Error checks occur later on */
#else
tmp="/tmp";
#endif
}
}
#endif
}
info->tempdir=xmalloc(strlen(tmp)+strlen(DIRSEP_S)+10+1);
sprintf(info->tempdir,"%s" DIRSEP_S "gpg-XXXXXX",tmp);
#if defined (_WIN32)
xfree(tmp);
#endif
if(mkdtemp(info->tempdir)==NULL)
log_error(_("can't create directory `%s': %s\n"),
info->tempdir,strerror(errno));
else
{
info->flags.madedir=1;
info->tempfile_in=xmalloc(strlen(info->tempdir)+
strlen(DIRSEP_S)+strlen(namein)+1);
sprintf(info->tempfile_in,"%s" DIRSEP_S "%s",info->tempdir,namein);
if(!info->flags.writeonly)
{
info->tempfile_out=xmalloc(strlen(info->tempdir)+
strlen(DIRSEP_S)+strlen(nameout)+1);
sprintf(info->tempfile_out,"%s" DIRSEP_S "%s",info->tempdir,nameout);
}
}
return info->flags.madedir?0:G10ERR_GENERAL;
}
/* Expands %i and %o in the args to the full temp files within the
temp directory. */
static int
expand_args(struct exec_info *info,const char *args_in)
{
const char *ch = args_in;
membuf_t command;
info->flags.use_temp_files=0;
info->flags.keep_temp_files=0;
if(DBG_EXTPROG)
log_debug("expanding string \"%s\"\n",args_in);
init_membuf (&command, 100);
while(*ch!='\0')
{
if(*ch=='%')
{
char *append=NULL;
ch++;
switch(*ch)
{
case 'O':
info->flags.keep_temp_files=1;
/* fall through */
case 'o': /* out */
if(!info->flags.madedir)
{
if(make_tempdir(info))
goto fail;
}
append=info->tempfile_out;
info->flags.use_temp_files=1;
break;
case 'I':
info->flags.keep_temp_files=1;
/* fall through */
case 'i': /* in */
if(!info->flags.madedir)
{
if(make_tempdir(info))
goto fail;
}
append=info->tempfile_in;
info->flags.use_temp_files=1;
break;
case '%':
append="%";
break;
}
if(append)
put_membuf_str (&command, append);
}
else
put_membuf (&command, ch, 1);
ch++;
}
put_membuf (&command, "", 1); /* Terminate string. */
info->command = get_membuf (&command, NULL);
if (!info->command)
return gpg_error_from_syserror ();
if(DBG_EXTPROG)
log_debug("args expanded to \"%s\", use %u, keep %u\n",info->command,
info->flags.use_temp_files,info->flags.keep_temp_files);
return 0;
fail:
xfree (get_membuf (&command, NULL));
return G10ERR_GENERAL;
}
/* Either handles the tempfile creation, or the fork/exec. If it
returns ok, then info->tochild is a FILE * that can be written to.
The rules are: if there are no args, then it's a fork/exec/pipe.
If there are args, but no tempfiles, then it's a fork/exec/pipe via
shell -c. If there are tempfiles, then it's a system. */
int
exec_write(struct exec_info **info,const char *program,
const char *args_in,const char *name,int writeonly,int binary)
{
int ret=G10ERR_GENERAL;
if(opt.exec_disable && !opt.no_perm_warn)
{
log_info(_("external program calls are disabled due to unsafe "
"options file permissions\n"));
return ret;
}
#if defined(HAVE_GETUID) && defined(HAVE_GETEUID)
/* There should be no way to get to this spot while still carrying
setuid privs. Just in case, bomb out if we are. */
if ( getuid () != geteuid ())
BUG ();
#endif
if(program==NULL && args_in==NULL)
BUG();
*info=xmalloc_clear(sizeof(struct exec_info));
if(name)
(*info)->name=xstrdup(name);
(*info)->flags.binary=binary;
(*info)->flags.writeonly=writeonly;
/* Expand the args, if any */
if(args_in && expand_args(*info,args_in))
goto fail;
#ifdef EXEC_TEMPFILE_ONLY
if(!(*info)->flags.use_temp_files)
{
log_error(_("this platform requires temporary files when calling"
" external programs\n"));
goto fail;
}
#else /* !EXEC_TEMPFILE_ONLY */
/* If there are no args, or there are args, but no temp files, we
can use fork/exec/pipe */
if(args_in==NULL || (*info)->flags.use_temp_files==0)
{
int to[2],from[2];
if(pipe(to)==-1)
goto fail;
if(pipe(from)==-1)
{
close(to[0]);
close(to[1]);
goto fail;
}
if(((*info)->child=fork())==-1)
{
close(to[0]);
close(to[1]);
close(from[0]);
close(from[1]);
goto fail;
}
if((*info)->child==0)
{
char *shell=getenv("SHELL");
if(shell==NULL)
shell="/bin/sh";
/* I'm the child */
/* If the program isn't going to respond back, they get to
keep their stdout/stderr */
if(!(*info)->flags.writeonly)
{
/* implied close of STDERR */
if(dup2(STDOUT_FILENO,STDERR_FILENO)==-1)
_exit(1);
/* implied close of STDOUT */
close(from[0]);
if(dup2(from[1],STDOUT_FILENO)==-1)
_exit(1);
}
/* implied close of STDIN */
close(to[1]);
if(dup2(to[0],STDIN_FILENO)==-1)
_exit(1);
if(args_in==NULL)
{
if(DBG_EXTPROG)
log_debug("execlp: %s\n",program);
execlp(program,program,(void *)NULL);
}
else
{
if(DBG_EXTPROG)
log_debug("execlp: %s -c %s\n",shell,(*info)->command);
execlp(shell,shell,"-c",(*info)->command,(void *)NULL);
}
/* If we get this far the exec failed. Clean up and return. */
if(args_in==NULL)
log_error(_("unable to execute program `%s': %s\n"),
program,strerror(errno));
else
log_error(_("unable to execute shell `%s': %s\n"),
shell,strerror(errno));
/* This mimics the POSIX sh behavior - 127 means "not found"
from the shell. */
if(errno==ENOENT)
_exit(127);
_exit(1);
}
/* I'm the parent */
close(to[0]);
(*info)->tochild=fdopen(to[1],binary?"wb":"w");
if((*info)->tochild==NULL)
{
ret = gpg_error_from_syserror ();
close(to[1]);
goto fail;
}
close(from[1]);
(*info)->fromchild=iobuf_fdopen(from[0],"r");
if((*info)->fromchild==NULL)
{
ret = gpg_error_from_syserror ();
close(from[0]);
goto fail;
}
/* fd iobufs are cached! */
iobuf_ioctl((*info)->fromchild, IOBUF_IOCTL_NO_CACHE, 1, NULL);
return 0;
}
#endif /* !EXEC_TEMPFILE_ONLY */
if(DBG_EXTPROG)
log_debug("using temp file `%s'\n",(*info)->tempfile_in);
/* It's not fork/exec/pipe, so create a temp file */
if( is_secured_filename ((*info)->tempfile_in) )
{
(*info)->tochild = NULL;
gpg_err_set_errno (EPERM);
}
else
(*info)->tochild=fopen((*info)->tempfile_in,binary?"wb":"w");
if((*info)->tochild==NULL)
{
ret = gpg_error_from_syserror ();
log_error(_("can't create `%s': %s\n"),
(*info)->tempfile_in,strerror(errno));
goto fail;
}
ret=0;
fail:
if (ret)
{
xfree (*info);
*info = NULL;
}
return ret;
}
int
exec_read(struct exec_info *info)
{
int ret=G10ERR_GENERAL;
fclose(info->tochild);
info->tochild=NULL;
if(info->flags.use_temp_files)
{
if(DBG_EXTPROG)
log_debug("system() command is %s\n",info->command);
#if defined (_WIN32)
info->progreturn=w32_system(info->command);
#else
info->progreturn=system(info->command);
#endif
if(info->progreturn==-1)
{
log_error(_("system error while calling external program: %s\n"),
strerror(errno));
info->progreturn=127;
goto fail;
}
#if defined(WIFEXITED) && defined(WEXITSTATUS)
if(WIFEXITED(info->progreturn))
info->progreturn=WEXITSTATUS(info->progreturn);
else
{
log_error(_("unnatural exit of external program\n"));
info->progreturn=127;
goto fail;
}
#else
/* If we don't have the macros, do the best we can. */
info->progreturn = (info->progreturn & 0xff00) >> 8;
#endif
/* 127 is the magic value returned from system() to indicate
that the shell could not be executed, or from /bin/sh to
indicate that the program could not be executed. */
if(info->progreturn==127)
{
log_error(_("unable to execute external program\n"));
goto fail;
}
if(!info->flags.writeonly)
{
info->fromchild=iobuf_open(info->tempfile_out);
if (info->fromchild
&& is_secured_file (iobuf_get_fd (info->fromchild)))
{
iobuf_close (info->fromchild);
info->fromchild = NULL;
gpg_err_set_errno (EPERM);
}
if(info->fromchild==NULL)
{
ret = gpg_error_from_syserror ();
log_error(_("unable to read external program response: %s\n"),
strerror(errno));
goto fail;
}
/* Do not cache this iobuf on close */
iobuf_ioctl(info->fromchild, IOBUF_IOCTL_NO_CACHE, 1, NULL);
}
}
ret=0;
fail:
return ret;
}
int
exec_finish(struct exec_info *info)
{
int ret=info->progreturn;
if(info->fromchild)
iobuf_close(info->fromchild);
if(info->tochild)
fclose(info->tochild);
#ifndef EXEC_TEMPFILE_ONLY
if(info->child>0)
{
if(waitpid(info->child,&info->progreturn,0)!=0 &&
WIFEXITED(info->progreturn))
ret=WEXITSTATUS(info->progreturn);
else
{
log_error(_("unnatural exit of external program\n"));
ret=127;
}
}
#endif
if(info->flags.madedir && !info->flags.keep_temp_files)
{
if(info->tempfile_in)
{
if(unlink(info->tempfile_in)==-1)
log_info(_("WARNING: unable to remove tempfile (%s) `%s': %s\n"),
"in",info->tempfile_in,strerror(errno));
}
if(info->tempfile_out)
{
if(unlink(info->tempfile_out)==-1)
log_info(_("WARNING: unable to remove tempfile (%s) `%s': %s\n"),
"out",info->tempfile_out,strerror(errno));
}
if(rmdir(info->tempdir)==-1)
log_info(_("WARNING: unable to remove temp directory `%s': %s\n"),
info->tempdir,strerror(errno));
}
xfree(info->command);
xfree(info->name);
xfree(info->tempdir);
xfree(info->tempfile_in);
xfree(info->tempfile_out);
xfree(info);
return ret;
}
#endif /* ! NO_EXEC */