src/util/pathsearch.c

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/*
 * Revision Control Information
 *
 * $Id: pathsearch.c,v 1.8 2009/01/05 21:04:04 fabio Exp $
 *
 */
/* LINTLIBRARY */

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

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

#include "util.h"

int
util_check_file(char const *filename, char const *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 && S_ISREG(stat_rec.st_mode)) {
        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
}

char *
util_path_search(char const *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(
  char const *file      /* file we're looking for */,
  char *path            /* search path, colon separated */,
  char const *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 (util_check_file(filename, mode)) {
            FREE(save_path);
            return filename;
        }
        FREE(filename);
        path = ++cp;
    } while (! quit); 

    FREE(save_path);
    return 0;
}

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