8322 nl: misleading-indentation

[unleashed/tickless.git] / usr / src / lib / libpkg / common / runcmd.c

/*
 * 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] = NULL;
        }
}

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 ((FILE *)0);
        }

        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 ((FILE *)0);
        }

        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 ((FILE *)0);
        }

        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));
}