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/* $OpenBSD: cmd_exec.c,v 1.10 2016/03/28 11:27:37 chl Exp $ */
/*
* Copyright (c) 2001 Marc Espie.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
* PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include "config.h"
#include "defines.h"
#include "cmd_exec.h"
#include "buf.h"
#include "memory.h"
#include "pathnames.h"
char *
Cmd_Exec(const char *cmd, char **err)
{
char *args[4]; /* Args for invoking the shell */
int fds[2]; /* Pipe streams */
pid_t cpid; /* Child PID */
char *result; /* Result */
int status; /* Command exit status */
BUFFER buf; /* Buffer to store the result. */
char *cp; /* Pointer into result. */
ssize_t cc; /* Characters read from pipe. */
size_t length; /* Total length of result. */
*err = NULL;
/* Set up arguments for the shell. */
args[0] = "sh";
args[1] = "-c";
args[2] = (char *)cmd;
args[3] = NULL;
/* Open a pipe for retrieving shell's output. */
if (pipe(fds) == -1) {
*err = "Couldn't create pipe for \"%s\"";
goto bad;
}
/* Fork */
switch (cpid = fork()) {
case 0:
/* Close input side of pipe */
(void)close(fds[0]);
/* Duplicate the output stream to the shell's output, then
* shut the extra thing down. Note we don't fetch the error
* stream: user can use redirection to grab it as this goes
* through /bin/sh.
*/
if (fds[1] != 1) {
(void)dup2(fds[1], 1);
(void)close(fds[1]);
}
(void)execv(_PATH_BSHELL, args);
_exit(1);
/*NOTREACHED*/
case -1:
*err = "Couldn't exec \"%s\"";
goto bad;
default:
/* No need for the writing half. */
(void)close(fds[1]);
Buf_Init(&buf, MAKE_BSIZE);
do {
char grab[BUFSIZ];
cc = read(fds[0], grab, sizeof(grab));
if (cc > 0)
Buf_AddChars(&buf, cc, grab);
} while (cc > 0 || (cc == -1 && errno == EINTR));
/* Close the input side of the pipe. */
(void)close(fds[0]);
/* Wait for the child to exit. */
while (waitpid(cpid, &status, 0) == -1 && errno == EINTR)
continue;
if (cc == -1)
*err = "Couldn't read shell's output for \"%s\"";
if (status)
*err = "\"%s\" returned non-zero status";
length = Buf_Size(&buf);
result = Buf_Retrieve(&buf);
/* The result is null terminated, Convert newlines to spaces. */
cp = result + length - 1;
if (cp >= result && *cp == '\n')
/* A final newline is just stripped. */
*cp-- = '\0';
while (cp >= result) {
if (*cp == '\n')
*cp = ' ';
cp--;
}
break;
}
return result;
bad:
return estrdup("");
}
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