files/t_stat.c

This is files/t_stat.c (Listing 15-1, page 284), an example from the book, The Linux Programming Interface.

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

This page shows the "distribution" or "book" version of the file (why are there two versions?), or the differences between the two versions. You can switch between the views using the tabs below.

In the listing below, the names of Linux system calls and C library functions are hyperlinked to manual pages from the Linux man-pages project, and the names of functions implemented in the book are hyperlinked to the implementations of those functions.

 

Download files/t_stat.c

  Cover of The Linux Programming Interface

Function list (Bold in this list means a function is not static)

/* t_stat.c

   A program that displays the information returned by the stat()/lstat()
   system calls.

   Usage: t_stat [-l] file

   The '-l' option indicates that lstat() rather than stat() should be used.
*/
#include <sys/sysmacros.h>
#if defined(_AIX)
#define _BSD
#endif
#if defined(__sgi) || defined(__sun)            /* Some systems need this */
#include <sys/mkdev.h>                          /* To get major() and minor() */
#endif
#if defined(__hpux)                             /* Other systems need this */
#include <sys/mknod.h>
#endif
#include <sys/stat.h>
#include <time.h>
#include "file_perms.h"
#include "tlpi_hdr.h"
static void
displayStatInfo(const struct stat *sb)
{
    printf("File type:                ");

    switch (sb->st_mode & S_IFMT) {
    case S_IFREG:  printf("regular file\n");            break;
    case S_IFDIR:  printf("directory\n");               break;
    case S_IFCHR:  printf("character device\n");        break;
    case S_IFBLK:  printf("block device\n");            break;
    case S_IFLNK:  printf("symbolic (soft) link\n");    break;
    case S_IFIFO:  printf("FIFO or pipe\n");            break;
    case S_IFSOCK: printf("socket\n");                  break;
    default:       printf("unknown file type?\n");      break;
    }

    printf("Device containing i-node: major=%ld   minor=%ld\n",
                (long) major(sb->st_dev), (long) minor(sb->st_dev));

    printf("I-node number:            %ld\n", (long) sb->st_ino);

    printf("Mode:                     %lo (%s)\n",
            (unsigned long) sb->st_mode, filePermStr(sb->st_mode, 0));

    if (sb->st_mode & (S_ISUID | S_ISGID | S_ISVTX))
        printf("    special bits set:     %s%s%s\n",
                (sb->st_mode & S_ISUID) ? "set-UID " : "",
                (sb->st_mode & S_ISGID) ? "set-GID " : "",
                (sb->st_mode & S_ISVTX) ? "sticky " : "");

    printf("Number of (hard) links:   %ld\n", (long) sb->st_nlink);

    printf("Ownership:                UID=%ld   GID=%ld\n",
            (long) sb->st_uid, (long) sb->st_gid);

    if (S_ISCHR(sb->st_mode) || S_ISBLK(sb->st_mode))
        printf("Device number (st_rdev):  major=%ld; minor=%ld\n",
                (long) major(sb->st_rdev), (long) minor(sb->st_rdev));

    printf("File size:                %lld bytes\n", (long long) sb->st_size);
    printf("Optimal I/O block size:   %ld bytes\n", (long) sb->st_blksize);
    printf("512B blocks allocated:    %lld\n", (long long) sb->st_blocks);

    printf("Last file access:         %s", ctime(&sb->st_atime));
    printf("Last file modification:   %s", ctime(&sb->st_mtime));
    printf("Last status change:       %s", ctime(&sb->st_ctime));
}
int
main(int argc, char *argv[])
{
    struct stat sb;
    Boolean statLink;           /* True if "-l" specified (i.e., use lstat) */
    int fname;                  /* Location of filename argument in argv[] */

    statLink = (argc > 1) && strcmp(argv[1], "-l") == 0;
                                /* Simple parsing for "-l" */
    fname = statLink ? 2 : 1;

    if (fname >= argc || (argc > 1 && strcmp(argv[1], "--help") == 0))
        usageErr("%s [-l] file\n"
                "        -l = use lstat() instead of stat()\n", argv[0]);

    if (statLink) {
        if (lstat(argv[fname], &sb) == -1)
            errExit("lstat");
    } else {
        if (stat(argv[fname], &sb) == -1)
            errExit("stat");
    }

    displayStatInfo(&sb);

    exit(EXIT_SUCCESS);
}

 

Download files/t_stat.c

Note that, in most cases, the programs rendered in these web pages are not free standing: you'll typically also need a few other source files (mostly in the lib/ subdirectory) as well. Generally, it's easier to just download the entire source tarball and build the programs with make(1). By hovering your mouse over the various hyperlinked include files and function calls above, you can see which other source files this file depends on.

Valid XHTML 1.1