cwd.c

/*
# _____     ___ ____     ___ ____
#  ____|   |    ____|   |        | |____|
# |     ___|   |____ ___|    ____| |    \    PS2DEV Open Source Project.
#-----------------------------------------------------------------------
# Copyright 2001-2004, ps2dev - http://www.ps2dev.org
# Licenced under Academic Free License version 2.0
# Review ps2sdk README & LICENSE files for further details.
*/
 
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <sys/param.h>
#include <dirent.h>
#include <errno.h>
#include <stdlib.h>
 
/* the present working directory variable. */
char __cwd[MAXNAMLEN + 1] = { 0 };
 
/* the length of the present working directory variable. */
size_t __cwd_len = 0;
 
#define defaultCWD "host:"
 
enum SeparatorType {
    SeparatorTypeNotFound,
    SeparatorTypeNone,
    SeparatorTypePOSIX,
    SeparatorTypeWindows,
};
 
#define isnum(c) ((c) >= '0' && (c) <= '9')
 
/* Return the number of bytes taken up by the "drive:" prefix,
   or -1 if it's not found */
int __get_drive(const char *dev, enum SeparatorType *usePOSIXSeparator, int maxLen)
{
    const char *t;
    const char *d;
    int devname_len;
 
    /* Skip leading spaces */
    for (d = dev; ((int)(d - dev) < maxLen) && *d == ' '; d += 1);
 
    /* Get colon position */
    for (t = d; ((int)(t - dev) < maxLen) && *t && *t != ':'; t += 1);
    if (*t != ':')
    {
        *usePOSIXSeparator = SeparatorTypeNotFound;
        return 0;
    }
 
    /* Reduce length to not include index */
    for (devname_len = (int)(t - d); isnum(d[devname_len - 1]); devname_len -= 1);
 
    *usePOSIXSeparator = SeparatorTypePOSIX;
    switch (devname_len)
    {
    case 3:
        /* These drivers don't have separator */
        if ((memcmp(d, "rom", devname_len) == 0) || (memcmp(d, "hdd", devname_len) == 0))
            *usePOSIXSeparator = SeparatorTypeNone;
        break;
    case 5:
        /* These drivers use \ as separator */
        if ((memcmp(d, "cdrom", devname_len) == 0))
            *usePOSIXSeparator = SeparatorTypeWindows;
        break;
    case 6:
        /* These drivers don't have separator */
        if ((memcmp(d, "usbkbd", devname_len) == 0))
            *usePOSIXSeparator = SeparatorTypeNone;
        break;
    default:
        break;
    }
 
    /* Return the length of the whole device name portion, including:
     * - leading spaces
     * - device name
     * - device index
     * - colon
     */
    return (t - dev) + 1;
}
 
char *getcwd(char *buf, size_t size)
{
    if (!buf)
    {
        size = __cwd_len + 1;
        buf = malloc(size);
        if (!buf)
        {
            errno = ENOMEM;
            return NULL;
        }
    }
    else if (!size)
    {
        errno = EINVAL;
        return NULL;
    }
    else if (size < (__cwd_len + 1))
    {
        errno = ERANGE;
        return NULL;
    }
 
    snprintf(buf, size, "%.*s", __cwd_len, __cwd);
    return buf;
}
 
/* Normalize a pathname (without leading "drive:") by removing
   . and .. components, duplicated /, etc. */
static int __path_normalize(char *out, int len, int posixSeparator)
{
    int i, j;
    int first, next;
    char separator = posixSeparator ? '/' : '\\';
    size_t out_len = strnlen(out, len);
 
    out_len += 2;
    if (out_len >= len) return -10;
 
    /* First append "/" to make the rest easier */
    out[out_len - 1] = separator;
    out[out_len] = 0;
 
    // Convert separators to the specified one
    for (size_t i = 0; i < out_len; i++) {
        if (out[i] == '/' || out[i] == '\\') {
            out[i] = separator;
        }
    }
 
    /* Convert "//" to "/" */
    for(i = 0; (i < out_len) && out[i+1]; i++) {
        if(out[i] == separator && out[i+1] == separator) {
            for(j=i+1; out[j]; j++)
                out[j] = out[j+1];
            i--;
        }
    }
 
    /* Convert "/./" to "/" */
    for(i = 0; (i < out_len) && out[i] && out[i+1] && out[i+2]; i++) {
        if(out[i] == separator && out[i+1] == '.' && out[i+2] == separator) {
            for(j = i+1; out[j]; j++)
                out[j] = out[j+2];
            i--;
        }
    }
 
    /* Convert "/asdf/../" to "/" until we can't anymore.  Also
     * convert leading "/../" to "/" */
    first = next = 0;
    while((first < out_len) && (next < out_len)) {
        /* If a "../" follows, remove it and the parent */
        if(out[next+1] && out[next+1] == '.' && 
           out[next+2] && out[next+2] == '.' &&
           out[next+3] && out[next+3] == separator) {
            for(j=0; out[first+j+1]; j++)
                out[first+j+1] = out[next+j+4];
            first = next = 0;
            continue;
        }
 
        /* Find next slash */
        first = next;
        for(next= first+1; out[next] && out[next] != separator; next++)
            continue;
        if(!out[next]) break;
    }
 
    /* Remove trailing "/" just if it's not the root */
    for(i = 1; (i < out_len) && out[i]; i++)
        continue;
    if(i > 1 && out[i-1] == separator) 
        out[i-1] = 0;
 
    return 0;
}
 
/* Convert relative path to absolute path. */
int __path_absolute(const char *in, char *out, int len)
{
    int dr;
    enum SeparatorType separatorType;
    size_t in_len;
    size_t out_len;
 
    in_len = strlen(in);
    /* See what the relative URL starts with */
    dr = __get_drive(in, &separatorType, in_len);
    char separator = separatorType == SeparatorTypePOSIX ? '/' : '\\';
 
    if((separatorType != SeparatorTypeNotFound) && (separatorType == SeparatorTypeNone || in[dr] == separator)) {
        /* It starts with "drive:" and has no separator or "drive:/", so it's already absolute */
        out_len = snprintf(out, len, "%.*s", in_len, in);
    } else if((separatorType != SeparatorTypeNotFound) && in[dr - 1] == ':') {
        /* It starts with "drive:", so it's already absoulte, however it misses the "/" after unit */
        out_len = snprintf(out, len, "%.*s%c%.*s", dr, in, separator, in_len - dr, in + dr);
    } else if(in[0] == '\\' || in[0] == '/') {
        /* It's absolute, but missing the drive, so use cwd's drive */
        out_len = snprintf(out, len, "%.*s%.*s", __get_drive(__cwd, &separatorType, __cwd_len), __cwd, in_len, in);
    } else {
        /* It's not absolute, so append it to the current cwd */
        out_len = snprintf(out, len, "%.*s%c%.*s", __cwd_len, __cwd, separator, in_len, in);
    }
    if (out_len >= len) return -1;
 
    /* Now normalize the pathname portion */
    dr = __get_drive(out, &separatorType, out_len);
    return __path_normalize(out + dr, len - dr, separatorType == SeparatorTypePOSIX);
}
 
/* Set the current working directory (CWD) to the path where the module was launched. */
void __init_cwd(int argc, char ** argv)
{
    if (argc == 0) {
        chdir("host:");
        return;
    }
    
    char * p, * s = NULL;
    // let's find the last slash, or at worst, the :
    for (p = argv[0]; *p; p++) {
        if ((*p == '/') || (*p == '\\') || (*p == ':')) {
            s = p;
        }
    }
    if (s == NULL)
    {
        chdir("host:");
        return;
    }
    char backup = *(++s);
    *s = 0;
    chdir(argv[0]);
    *s = backup;
}