source: mainline/uspace/app/sbi/src/os/posix.c

/*
 * Copyright (c) 2010 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @file POSIX-specific code. */

#include <assert.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <types/common.h>
#include <sys/wait.h>
#include <unistd.h>
#include <errno.h>
#include "../mytypes.h"

#include "os.h"

/** Path to executable file via which we have been invoked. */
static char *ef_path;

/*
 * The string functions are in fact standard C, but would not work under
 * HelenOS.
 *
 * XXX String functions used here only work with 8-bit text encoding.
 */

/** Concatenate two strings.
 *
 * @param a     First string
 * @param b     Second string
 * @return      New string, concatenation of @a a and @a b.
 */
char *os_str_acat(const char *a, const char *b)
{
        int a_len, b_len;
        char *str;

        a_len = strlen(a);
        b_len = strlen(b);

        str = malloc(a_len + b_len + 1);
        if (str == NULL) {
                printf("Memory allocation error.\n");
                exit(1);
        }

        memcpy(str, a, a_len);
        memcpy(str + a_len, b, b_len);
        str[a_len + b_len] = '\0';

        return str;
}

/** Return slice (substring) of a string.
 *
 * Copies the specified range of characters from @a str and returns it
 * as a newly allocated string. @a start + @a length must be less than
 * or equal to the length of @a str.
 *
 * @param str           String
 * @param start         Index of first character (starting from zero).
 * @param length        Number of characters to copy.
 *
 * @return              Newly allocated string holding the slice.
 */
char *os_str_aslice(const char *str, size_t start, size_t length)
{
        char *slice;

        assert(start + length <= strlen(str));
        slice = malloc(length + 1);
        if (slice == NULL) {
                printf("Memory allocation error.\n");
                exit(1);
        }

        strncpy(slice, str + start, length);
        slice[length] = '\0';

        return slice;
}

/** Compare two strings.
 *
 * @param a     First string
 * @param b     Second string
 * @return      Zero if equal, nonzero if not equal
 */
errno_t os_str_cmp(const char *a, const char *b)
{
        return strcmp(a, b);
}

/** Return number of characters in string.
 *
 * @param str   String
 * @return      Number of characters in @a str.
 */
size_t os_str_length(const char *str)
{
        return strlen(str);
}

/** Duplicate string.
 *
 * @param str   String
 * @return      New string, duplicate of @a str.
 */
char *os_str_dup(const char *str)
{
        return strdup(str);
}

/** Get character from string at the given index.
 *
 * @param str           String
 * @param index         Character index (starting from zero).
 * @param out_char      Place to store character.
 * @return              EOK on success, EINVAL if index is out of bounds,
 *                      EIO on decoding error.
 */
errno_t os_str_get_char(const char *str, int index, int *out_char)
{
        size_t len;

        len = strlen(str);
        if (index < 0 || (size_t) index >= len)
                return EINVAL;

        *out_char = str[index];
        return EOK;
}

/** Convert character to new string.
 *
 * @param chr           Character
 * @return              Newly allocated string.
 */
char *os_chr_to_astr(char32_t chr)
{
        char *str;

        str = malloc(2);
        if (str == NULL) {
                printf("Memory allocation error.\n");
                exit(1);
        }

        str[0] = (char) chr;
        str[1] = '\0';

        return str;
}

#define OS_INPUT_BUFFER_SIZE 256
static char os_input_buffer[OS_INPUT_BUFFER_SIZE];

/** Display survival help message. */
void os_input_disp_help(void)
{
        printf("Send ^C (SIGINT) to quit.\n");
}

/** Read one line of input from the user.
 *
 * @param ptr   Place to store pointer to new string.
 */
errno_t os_input_line(const char *prompt, char **ptr)
{
        printf("%s", prompt);

        if (fgets(os_input_buffer, OS_INPUT_BUFFER_SIZE, stdin) == NULL)
                os_input_buffer[0] = '\0';

        if (ferror(stdin)) {
                *ptr = NULL;
                return EIO;
        }

        *ptr = strdup(os_input_buffer);
        return EOK;
}

/** Simple command execution.
 *
 * @param cmd   Command and arguments (NULL-terminated list of strings.)
 *              Command is present just one, not duplicated.
 */
errno_t os_exec(char *const cmd[])
{
        pid_t pid;
        int status;

        pid = vfork();

        if (pid == 0) {
                execvp(cmd[0], cmd);
                /* If we get here, exec failed. */
                exit(1);
        } else if (pid == -1) {
                /* fork() failed */
                return EBUSY;
        }

        if (waitpid(pid, &status, 0) == -1) {
                /* waitpid() failed */
                printf("Error: Waitpid failed.\n");
                exit(1);
        }

        if (WIFEXITED(status) && WEXITSTATUS(status) != 0) {
                printf("Error: Exec failed or child returned non-zero "
                    "exit status.\n");
        }

        return EOK;
}

/** Store the executable file path via which we were executed.
 *
 * @param path  Executable path via which we were executed.
 */
void os_store_ef_path(char *path)
{
        ef_path = path;
}

/** Return path to the Sysel library
 *
 * @return New string. Caller should deallocate it using @c free().
 */
char *os_get_lib_path(void)
{
        return os_str_acat(dirname(ef_path), "/lib");
}