xref: /illumos-gate/usr/src/lib/libpkg/common/runcmd.c (revision b3403853e80914bd0aade9b5b605da4878078173)

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/* All Rights Reserved */



#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <strings.h>
#include <signal.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <wait.h>
#include <sys/types.h>
#include "pkglib.h"
#include "pkglocale.h"
#include "pkglibmsgs.h"

#ifndef _STDARG_H
#include "stdarg.h"
#endif

/*
 * Private definitions
 */

/* Maximum number of arguments to pkg_ExecCmdList */

#define	MAX_EXEC_CMD_ARGS	100

/* Size of buffer increments when reading from pipe */

#define	PIPE_BUFFER_INCREMENT	256

static char	errfile[L_tmpnam+1];

/*
 * Public Methods
 */


void
rpterr(void)
{
	FILE	*fp;
	int	c;

	if (errfile[0]) {
		if (fp = fopen(errfile, "r")) {
			while ((c = getc(fp)) != EOF)
				(void) putc(c, stderr);
			(void) fclose(fp);
		}
		(void) unlink(errfile);
		errfile[0] = '\0';
	}
}

void
ecleanup(void)
{
	if (errfile[0]) {
		(void) unlink(errfile);
		errfile[0] = '\0';
	}
}

int
esystem(char *cmd, int ifd, int ofd)
{
	char	*perrfile;
	int	status = 0;
	pid_t	pid;

	perrfile = tmpnam(NULL);
	if (perrfile == NULL) {
		progerr(
		    pkg_gt("unable to create temp error file, errno=%d"),
		    errno);
		return (-1);
	}
	(void) strlcpy(errfile, perrfile, sizeof (errfile));

	/* flush standard i/o before creating new process */

	(void) fflush(stderr);
	(void) fflush(stdout);

	/*
	 * create new process to execute command in;
	 * vfork() is being used to avoid duplicating the parents
	 * memory space - this means that the child process may
	 * not modify any of the parents memory including the
	 * standard i/o descriptors - all the child can do is
	 * adjust interrupts and open files as a prelude to a
	 * call to exec().
	 */

	pid = vfork();
	if (pid == 0) {
		/*
		 * this is the child process
		 */
		int	i;

		/* reset any signals to default */

		for (i = 0; i < NSIG; i++) {
			(void) sigset(i, SIG_DFL);
		}

		if (ifd > 0) {
			(void) dup2(ifd, STDIN_FILENO);
		}

		if (ofd >= 0 && ofd != STDOUT_FILENO) {
			(void) dup2(ofd, STDOUT_FILENO);
		}

		i = open(errfile, O_WRONLY|O_CREAT|O_TRUNC, 0666);
		if (i >= 0) {
			(void) dup2(i, STDERR_FILENO);
		}

		/* Close all open files except standard i/o */

		closefrom(3);

		/* execute target executable */

		(void) execl("/sbin/sh", "/sbin/sh", "-c", cmd, NULL);
		progerr(pkg_gt("exec of <%s> failed, errno=%d"), cmd, errno);
		_exit(99);
	} else if (pid < 0) {
		/* fork failed! */

		logerr(pkg_gt("bad vfork(), errno=%d"), errno);
		return (-1);
	}

	/*
	 * this is the parent process
	 */

	(void) sighold(SIGINT);
	pid = waitpid(pid, &status, 0);
	(void) sigrelse(SIGINT);

	if (pid < 0) {
		return (-1); /* probably interrupted */
	}

	switch (status & 0177) {
		case 0:
		case 0177:
			status = status >> 8;
			/*FALLTHROUGH*/

		default:
			/* terminated by a signal */
			status = status & 0177;
	}

	if (status == 0) {
		ecleanup();
	}

	return (status);
}

FILE *
epopen(char *cmd, char *mode)
{
	char	*buffer, *perrfile;
	FILE	*pp;
	size_t	len;
	size_t	alen;

	if (errfile[0]) {
		/* cleanup previous errfile */
		(void) unlink(errfile);
	}

	perrfile = tmpnam(NULL);
	if (perrfile == NULL) {
		progerr(
		    pkg_gt("unable to create temp error file, errno=%d"),
		    errno);
		return ((FILE *)0);
	}

	if (strlcpy(errfile, perrfile, sizeof (errfile)) > sizeof (errfile)) {
		progerr(pkg_gt("file name max length %d; name is too long: %s"),
		    sizeof (errfile), perrfile);
		return (NULL);
	}

	len = strlen(cmd)+6+strlen(errfile);
	buffer = (char *)calloc(len, sizeof (char));
	if (buffer == NULL) {
		progerr(pkg_gt("no memory in epopen(), errno=%d"), errno);
		return (NULL);
	}

	if (strchr(cmd, '|')) {
		alen = snprintf(buffer, len, "(%s) 2>%s", cmd, errfile);
	} else {
		alen = snprintf(buffer, len, "%s 2>%s", cmd, errfile);
	}

	if (alen > len) {
		progerr(pkg_gt("command max length %d; cmd is too long: %s"),
		    len, cmd);
		return (NULL);
	}

	pp = popen(buffer, mode);

	free(buffer);
	return (pp);
}

int
epclose(FILE *pp)
{
	int n;

	n = pclose(pp);
	if (n == 0)
		ecleanup();
	return (n);
}

/*
 * Name:	e_ExecCmdArray
 * Synopsis:	Execute Unix command and return results
 * Description:	Execute a Unix command and return results and status
 * Arguments:
 *		r_status - [RO, *RW] - (int *)
 *			Return (exit) status from Unix command:
 *			== -1 : child terminated with a signal
 *			!= -1 : lower 8-bit value child passed to exit()
 *		r_results - [RO, *RW] - (char **)
 *			Any output generated by the Unix command to stdout
 *			and to stderr
 *			== (char *)NULL if no output generated
 *		a_inputFile - [RO, *RO] - (char *)
 *			Pointer to character string representing file to be
 *			used as "standard input" for the command.
 *			== (char *)NULL to use "/dev/null" as standard input
 *		a_cmd - [RO, *RO] - (char *)
 *			Pointer to character string representing the full path
 *			of the Unix command to execute
 *		char **a_args - [RO, *RO] - (char **)
 *			List of character strings representing the arguments
 *			to be passed to the Unix command. The list must be
 *			terminated with an element that is (char *)NULL
 * Returns:	int
 *			== 0 - Command executed
 *				Look at r_status for results of Unix command
 *			!= 0 - problems executing command
 *				r_status and r_results have no meaning;
 *				r_status will be -1
 *				r_results will be NULL
 * NOTE:	Any results returned is placed in new storage for the
 *		calling method. The caller must use 'free' to dispose
 *		of the storage once the results are no longer needed.
 * NOTE:	If 0 is returned, 'r_status' must be queried to
 *		determine the results of the Unix command.
 * NOTE:	The system "errno" value from immediately after waitpid() call
 *		is preserved for the calling method to use to determine
 *		the system reason why the operation failed.
 */

int
e_ExecCmdArray(int *r_status, char **r_results,
    char *a_inputFile, char *a_cmd, char **a_args)
{
	char		*buffer;
	int		bufferIndex;
	int		bufferSize;
	int		ipipe[2] = {0, 0};
	pid_t		pid;
	pid_t		resultPid;
	int		status;
	int		lerrno;
	int		stdinfile = -1;

	/* reset return results buffer pointer */

	if (r_results != (char **)NULL) {
		*r_results = (char *)NULL;
	}

	*r_status = -1;

	/*
	 * See if command exists
	 */

	if (access(a_cmd, F_OK|X_OK) != 0) {
		return (-1);
	}

	/*
	 * See if input file exists
	 */

	if (a_inputFile != (char *)NULL) {
		stdinfile = open(a_inputFile, O_RDONLY);
	} else {
		stdinfile = open("/dev/null", O_RDONLY); /* stdin = /dev/null */
	}

	if (stdinfile < 0) {
		return (-1);
	}

	/*
	 * Create a pipe to be used to capture the command output
	 */

	if (pipe(ipipe) != 0) {
		(void) close(stdinfile);
		return (-1);
	}


	bufferSize = PIPE_BUFFER_INCREMENT;
	bufferIndex = 0;
	buffer = calloc(1, bufferSize);
	if (buffer == (char *)NULL) {
		(void) close(stdinfile);
		return (-1);
	}

	/* flush standard i/o before creating new process */

	(void) fflush(stderr);
	(void) fflush(stdout);

	/*
	 * create new process to execute command in;
	 * vfork() is being used to avoid duplicating the parents
	 * memory space - this means that the child process may
	 * not modify any of the parents memory including the
	 * standard i/o descriptors - all the child can do is
	 * adjust interrupts and open files as a prelude to a
	 * call to exec().
	 */

	pid = vfork();

	if (pid == 0) {
		/*
		 * This is the forked (child) process ======================
		 */

		int	i;

		/* reset any signals to default */

		for (i = 0; i < NSIG; i++) {
			(void) sigset(i, SIG_DFL);
		}

		/* assign stdin, stdout, stderr as appropriate */

		(void) dup2(stdinfile, STDIN_FILENO);
		(void) close(ipipe[0]);		/* close out pipe reader side */
		(void) dup2(ipipe[1], STDOUT_FILENO);
		(void) dup2(ipipe[1], STDERR_FILENO);

		/* Close all open files except standard i/o */

		closefrom(3);

		/* execute target executable */

		(void) execvp(a_cmd, a_args);
		perror(a_cmd);	/* Emit error msg - ends up in callers buffer */
		_exit(0x00FE);
	}

	/*
	 * This is the forking (parent) process ====================
	 */

	(void) close(stdinfile);
	(void) close(ipipe[1]);		/* Close write side of pipe */

	/*
	 * Spin reading data from the child into the buffer - when the read eofs
	 * the child has exited
	 */

	for (;;) {
		ssize_t	bytesRead;

		/* read as much child data as there is available buffer space */

		bytesRead = read(ipipe[0], buffer + bufferIndex,
		    bufferSize - bufferIndex);

		/* break out of read loop if end-of-file encountered */

		if (bytesRead == 0) {
			break;
		}

		/* if error, continue if recoverable, else break out of loop */

		if (bytesRead == -1) {
			/* try again: EAGAIN - insufficient resources */

			if (errno == EAGAIN) {
				continue;
			}

			/* try again: EINTR - interrupted system call */

			if (errno == EINTR) {
				continue;
			}

			/* break out of loop - error not recoverable */
			break;
		}

		/* at least 1 byte read: expand buffer if at end */

		bufferIndex += bytesRead;
		if (bufferIndex >= bufferSize) {
			buffer = realloc(buffer,
			    bufferSize += PIPE_BUFFER_INCREMENT);
			(void) memset(buffer + bufferIndex, 0,
			    bufferSize - bufferIndex);
		}
	}

	(void) close(ipipe[0]);		/* Close read side of pipe */

	/* Get subprocess exit status */

	for (;;) {
		resultPid = waitpid(pid, &status, 0L);
		lerrno = (resultPid == -1 ? errno : 0);

		/* break loop if child process status reaped */

		if (resultPid != -1) {
			break;
		}

		/* break loop if not interrupted out of waitpid */

		if (errno != EINTR) {
			break;
		}
	}

	/*
	 * If the child process terminated due to a call to exit(), then
	 * set results equal to the 8-bit exit status of the child process;
	 * otherwise, set the exit status to "-1" indicating that the child
	 * exited via a signal.
	 */

	*r_status = WIFEXITED(status) ? WEXITSTATUS(status) : -1;

	/* return appropriate output */

	if (!*buffer) {
		/* No contents in output buffer - discard */
		free(buffer);
	} else if (r_results == (char **)NULL) {
		/* Not requested to return results - discard */
		free(buffer);
	} else {
		/* have output and request to return: pass to calling method */
		*r_results = buffer;
	}

	errno = lerrno;
	return (resultPid == -1 ? -1 : 0);
}

/*
 * Name:	e_ExecCmdList
 * Synopsis:	Execute Unix command and return results
 * Description:	Execute a Unix command and return results and status
 * Arguments:
 *		r_status - [RO, *RW] - (int *)
 *			Return (exit) status from Unix command
 *		r_results - [RO, *RW] - (char **)
 *			Any output generated by the Unix command to stdout
 *			and to stderr
 *			== (char *)NULL if no output generated
 *		a_inputFile - [RO, *RO] - (char *)
 *			Pointer to character string representing file to be
 *			used as "standard input" for the command.
 *			== (char *)NULL to use "/dev/null" as standard input
 *		a_cmd - [RO, *RO] - (char *)
 *			Pointer to character string representing the full path
 *			of the Unix command to execute
 *		... - [RO] (?)
 *			Zero or more arguments to the Unix command
 *			The argument list must be ended with (void *)NULL
 * Returns:	int
 *			== 0 - Command executed
 *				Look at r_status for results of Unix command
 *			!= 0 - problems executing command
 *				r_status and r_results have no meaning
 * NOTE:	Any results returned is placed in new storage for the
 *		calling method. The caller must use 'free' to dispose
 *		of the storage once the results are no longer needed.
 * NOTE:	If LU_SUCCESS is returned, 'r_status' must be queried to
 *		determine the results of the Unix command.
 */

int
e_ExecCmdList(int *r_status, char **r_results,
    char *a_inputFile, char *a_cmd, ...)
{
	va_list		ap;		/* references variable argument list */
	char		*array[MAX_EXEC_CMD_ARGS+1];
	int		argno = 0;

	/*
	 * Create argument array for exec system call
	 */

	bzero(array, sizeof (array));

	va_start(ap, a_cmd);	/* Begin variable argument processing */

	for (argno = 0; argno < MAX_EXEC_CMD_ARGS; argno++) {
		array[argno] = va_arg(ap, char *);
		if (array[argno] == (char *)NULL) {
			break;
		}
	}

	va_end(ap);
	return (e_ExecCmdArray(r_status, r_results, a_inputFile, a_cmd, array));
}