/*
 * Revision Control Information
 *
 * /projects/hsis/CVS/utilities/util/pathsearch.c,v
 * rajeev
 * 1.3
 * 1995/08/08 22:41:24
 *
 */
/* LINTLIBRARY */

#if HAVE_SYS_FILE_H
#  include <sys/file.h>
#endif

#if HAVE_SYS_STAT_H
#  include <sys/stat.h>
#endif

#include "util.h"

/**Function********************************************************************

  Synopsis           [ Check that a given file is present and accessible ]

  SideEffects        [none]
******************************************************************************/
static int
check_file(filename, mode)
char *filename;
char *mode;
{
#if defined(HAVE_SYS_STAT_H)
    struct stat stat_rec;
    int access_char = mode[0];
    int access_mode = R_OK;

    /* First check that the file is a regular file. */

    if (stat(filename,&stat_rec) == 0
            && (stat_rec.st_mode&S_IFMT) == S_IFREG) {
    if (access_char == 'w') {
        access_mode = W_OK;
    } else if (access_char == 'x') {
        access_mode = X_OK;
    }
    return access(filename,access_mode) == 0;
    }
    return 0;

#else

    FILE *fp;
    int got_file;

    if (strcmp(mode, "x") == 0) {
    mode = "r";
    }
    fp = fopen(filename, mode);
    got_file = (fp != 0);
    if (fp != 0) {
    (void) fclose(fp);
    }
    return got_file;

#endif
}

/**Function********************************************************************

  Synopsis           [ Search for a program in all possible paths ]

  SideEffects        [none]

******************************************************************************/
char *
util_path_search(prog)
char *prog;
{
#ifdef HAVE_GETENV
    return util_file_search(prog, getenv("PATH"), "x");
#else
    return util_file_search(prog, NIL(char), "x");
#endif
}

char *
util_file_search(file, path, mode)
char *file;            /* file we're looking for */
char *path;            /* search path, colon separated */
char *mode;            /* "r", "w", or "x" */
{
    int quit;
    char *buffer, *filename, *save_path, *cp;

    if (path == 0 || strcmp(path, "") == 0) {
    path = ".";        /* just look in the current directory */
    }

    save_path = path = util_strsav(path);
    quit = 0;
    do {
    cp = strchr(path, ':');
    if (cp != 0) {
        *cp = '\0';
    } else {
        quit = 1;
    }

    /* cons up the filename out of the path and file name */
    if (strcmp(path, ".") == 0) {
        buffer = util_strsav(file);
    } else {
        buffer = ALLOC(char, strlen(path) + strlen(file) + 4);
        (void) sprintf(buffer, "%s/%s", path, file);
    }
    filename = util_tilde_expand(buffer);
    FREE(buffer);

    /* see if we can access it */
    if (check_file(filename, mode)) {
        FREE(save_path);
        return filename;
    }
    FREE(filename);
    path = ++cp;
    } while (! quit); 

    FREE(save_path);
    return 0;
}