src/platform_unix.c
author Ryan C. Gordon <icculus@icculus.org>
Mon, 19 Mar 2012 20:42:41 -0400
changeset 1236 ad779490c5b6
parent 1230 ca5575b87b22
child 1240 22d4d1bd4e21
permissions -rw-r--r--
Try to make a sane default for CD detection path by platform. This is so this can work even when dropping PhysicsFS into another project without CMake doing header tests and filling in the defines.

/*
 * Unix support routines for PhysicsFS.
 *
 * Please see the file LICENSE.txt in the source's root directory.
 *
 *  This file written by Ryan C. Gordon.
 */

#define __PHYSICSFS_INTERNAL__
#include "physfs_platforms.h"

#ifdef PHYSFS_PLATFORM_UNIX

#include <ctype.h>
#include <unistd.h>
#include <sys/types.h>
#include <pwd.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <dirent.h>
#include <time.h>
#include <errno.h>

#if PHYSFS_PLATFORM_LINUX && !defined(PHYSFS_HAVE_MNTENT_H)
#define PHYSFS_HAVE_MNTENT_H 1
#elif PHYSFS_PLATFORM_SOLARIS && !defined(PHYSFS_HAVE_SYS_MNTTAB_H)
#define PHYSFS_HAVE_SYS_MNTTAB_H 1
#elif PHYSFS_PLATFORM_BSD && !defined(PHYSFS_HAVE_SYS_UCRED_H)
#define PHYSFS_HAVE_SYS_UCRED_H 1
#endif

#ifdef PHYSFS_HAVE_SYS_UCRED_H
#  ifdef PHYSFS_HAVE_MNTENT_H
#    undef PHYSFS_HAVE_MNTENT_H /* don't do both... */
#  endif
#  include <sys/mount.h>
#  include <sys/ucred.h>
#endif

#ifdef PHYSFS_HAVE_MNTENT_H
#include <mntent.h>
#endif

#ifdef PHYSFS_HAVE_SYS_MNTTAB_H
#include <sys/mnttab.h>
#endif

#include "physfs_internal.h"

int __PHYSFS_platformInit(void)
{
    return 1;  /* always succeed. */
} /* __PHYSFS_platformInit */


int __PHYSFS_platformDeinit(void)
{
    return 1;  /* always succeed. */
} /* __PHYSFS_platformDeinit */


/* Stub version for platforms without CD-ROM support. */
void __PHYSFS_platformDetectAvailableCDs(PHYSFS_StringCallback cb, void *data)
{
#if (defined PHYSFS_NO_CDROM_SUPPORT)
    /* no-op. */

#elif (defined PHYSFS_HAVE_SYS_UCRED_H)
    int i;
    struct statfs *mntbufp = NULL;
    int mounts = getmntinfo(&mntbufp, MNT_WAIT);

    for (i = 0; i < mounts; i++)
    {
        int add_it = 0;

        if (strcmp(mntbufp[i].f_fstypename, "iso9660") == 0)
            add_it = 1;
        else if (strcmp( mntbufp[i].f_fstypename, "cd9660") == 0)
            add_it = 1;

        /* add other mount types here */

        if (add_it)
            cb(data, mntbufp[i].f_mntonname);
    } /* for */

#elif (defined PHYSFS_HAVE_MNTENT_H)
    FILE *mounts = NULL;
    struct mntent *ent = NULL;

    mounts = setmntent("/etc/mtab", "r");
    BAIL_IF_MACRO(mounts == NULL, ERR_IO_ERROR, /*return void*/);

    while ( (ent = getmntent(mounts)) != NULL )
    {
        int add_it = 0;
        if (strcmp(ent->mnt_type, "iso9660") == 0)
            add_it = 1;
        else if (strcmp(ent->mnt_type, "udf") == 0)
            add_it = 1;

        /* !!! FIXME: these might pick up floppy drives, right? */
        else if (strcmp(ent->mnt_type, "auto") == 0)
            add_it = 1;
        else if (strcmp(ent->mnt_type, "supermount") == 0)
            add_it = 1;

        /* !!! FIXME: udf? automount? */

        /* add other mount types here */

        if (add_it)
            cb(data, ent->mnt_dir);
    } /* while */

    endmntent(mounts);

#elif (defined PHYSFS_HAVE_SYS_MNTTAB_H)
    FILE *mounts = fopen(MNTTAB, "r");
    struct mnttab ent;

    BAIL_IF_MACRO(mounts == NULL, ERR_IO_ERROR, /*return void*/);
    while (getmntent(mounts, &ent) == 0)
    {
        int add_it = 0;
        if (strcmp(ent.mnt_fstype, "hsfs") == 0)
            add_it = 1;

        /* add other mount types here */

        if (add_it)
            cb(data, ent.mnt_mountp);
    } /* while */

    fclose(mounts);

#else
#error Unknown platform. Should have defined PHYSFS_NO_CDROM_SUPPORT, perhaps.
#endif
} /* __PHYSFS_platformDetectAvailableCDs */


/* this is in posix.c ... */
extern char *__PHYSFS_platformCopyEnvironmentVariable(const char *varname);


/*
 * See where program (bin) resides in the $PATH specified by (envr).
 *  returns a copy of the first element in envr that contains it, or NULL
 *  if it doesn't exist or there were other problems. PHYSFS_SetError() is
 *  called if we have a problem.
 *
 * (envr) will be scribbled over, and you are expected to allocator.Free() the
 *  return value when you're done with it.
 */
static char *findBinaryInPath(const char *bin, char *envr)
{
    size_t alloc_size = 0;
    char *exe = NULL;
    char *start = envr;
    char *ptr;

    BAIL_IF_MACRO(bin == NULL, ERR_INVALID_ARGUMENT, NULL);
    BAIL_IF_MACRO(envr == NULL, ERR_INVALID_ARGUMENT, NULL);

    do
    {
        size_t size;
        ptr = strchr(start, ':');  /* find next $PATH separator. */
        if (ptr)
            *ptr = '\0';

        size = strlen(start) + strlen(bin) + 2;
        if (size > alloc_size)
        {
            char *x = (char *) allocator.Realloc(exe, size);
            if (x == NULL)
            {
                if (exe != NULL)
                    allocator.Free(exe);
                BAIL_MACRO(ERR_OUT_OF_MEMORY, NULL);
            } /* if */

            alloc_size = size;
            exe = x;
        } /* if */

        /* build full binary path... */
        strcpy(exe, start);
        if ((exe[0] == '\0') || (exe[strlen(exe) - 1] != '/'))
            strcat(exe, "/");
        strcat(exe, bin);

        if (access(exe, X_OK) == 0)  /* Exists as executable? We're done. */
        {
            strcpy(exe, start);  /* i'm lazy. piss off. */
            return exe;
        } /* if */

        start = ptr + 1;  /* start points to beginning of next element. */
    } while (ptr != NULL);

    if (exe != NULL)
        allocator.Free(exe);

    return NULL;  /* doesn't exist in path. */
} /* findBinaryInPath */


static char *readSymLink(const char *path)
{
    ssize_t len = 64;
    ssize_t rc = -1;
    char *retval = NULL;

    while (1)
    {
         char *ptr = (char *) allocator.Realloc(retval, (size_t) len);
         if (ptr == NULL)
             break;   /* out of memory. */
         retval = ptr;

         rc = readlink(path, retval, len);
         if (rc == -1)
             break;  /* not a symlink, i/o error, etc. */

         else if (rc < len)
         {
             retval[rc] = '\0';  /* readlink doesn't null-terminate. */
             return retval;  /* we're good to go. */
         } /* else if */

         len *= 2;  /* grow buffer, try again. */
    } /* while */

    if (retval != NULL)
        allocator.Free(retval);
    return NULL;
} /* readSymLink */


char *__PHYSFS_platformCalcBaseDir(const char *argv0)
{
    char *retval = NULL;
    char *envr = NULL;

    /* fast path: default behaviour can handle this. */
    if ( (argv0 != NULL) && (strchr(argv0, '/') != NULL) )
        return NULL;  /* higher level will parse out real path from argv0. */

    /*
     * Try to avoid using argv0 unless forced to. If there's a Linux-like
     *  /proc filesystem, you can get the full path to the current process from
     *  the /proc/self/exe symlink.
     */
    retval = readSymLink("/proc/self/exe");
    if (retval == NULL)
    {
        /* older kernels don't have /proc/self ... try PID version... */
        const unsigned long long pid = (unsigned long long) getpid();
        char path[64];
        const int rc = (int) snprintf(path,sizeof(path),"/proc/%llu/exe",pid);
        if ( (rc > 0) && (rc < sizeof(path)) )
            retval = readSymLink(path);
    } /* if */

    if (retval != NULL)  /* chop off filename. */
    {
        char *ptr = strrchr(retval, '/');
        if (ptr != NULL)
            *ptr = '\0';
    } /* if */

    if ((retval == NULL) && (argv0 != NULL))
    {
        /* If there's no dirsep on argv0, then look through $PATH for it. */
        envr = __PHYSFS_platformCopyEnvironmentVariable("PATH");
        BAIL_IF_MACRO(!envr, NULL, NULL);
        retval = findBinaryInPath(argv0, envr);
        allocator.Free(envr);
    } /* if */

    if (retval != NULL)
    {
        /* try to shrink buffer... */
        char *ptr = (char *) allocator.Realloc(retval, strlen(retval) + 1);
        if (ptr != NULL)
            retval = ptr;  /* oh well if it failed. */
    } /* if */

    return retval;
} /* __PHYSFS_platformCalcBaseDir */


int __PHYSFS_platformSetDefaultAllocator(PHYSFS_Allocator *a)
{
    return 0;  /* just use malloc() and friends. */
} /* __PHYSFS_platformSetDefaultAllocator */

#endif /* PHYSFS_PLATFORM_UNIX */

/* end of unix.c ... */