1. 코드 분석

1. tlpi-dist/files/t_stat.c

1. 코드

/* 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);
}

2. 동작 모습

3. 디버깅 및 분석

2. tlpi-dist/files/t_chown.c

1. 코드

/* t_chown.c

   Demonstrate the use of the chown() system call to change the owner
   and group of a file.

   Usage: t_chown owner group [file...]

   Either or both of owner and/or group can be specified as "-" to
   leave them unchanged.
*/
#include <pwd.h>
#include <grp.h>
#include "ugid_functions.h"             /* Declarations of userIdFromName()
                                           and groupIdFromName() */
#include "tlpi_hdr.h"

int
main(int argc, char *argv[])
{
    uid_t uid;
    gid_t gid;
    int j;
    Boolean errFnd;

    if (argc < 3 || strcmp(argv[1], "--help") == 0)
        usageErr("%s owner group [file...]\n"
                "        owner or group can be '-', "
                "meaning leave unchanged\n", argv[0]);

    if (strcmp(argv[1], "-") == 0) {            /* "-" ==> don't change owner */
        uid = -1;
    } else {                                    /* Turn user name into UID */
        uid = userIdFromName(argv[1]);
        if (uid == -1)
            fatal("No such user (%s)", argv[1]);
    }

    if (strcmp(argv[2], "-") == 0) {            /* "-" ==> don't change group */
        gid = -1;
    } else {                                    /* Turn group name into GID */
        gid = groupIdFromName(argv[2]);
        if (gid == -1)
            fatal("No group user (%s)", argv[2]);
    }

    /* Change ownership of all files named in remaining arguments */

    errFnd = FALSE;
    for (j = 3; j < argc; j++) {
        if (chown(argv[j], uid, gid) == -1) {
            errMsg("chown: %s", argv[j]);
            errFnd = TRUE;
        }
    }

    exit(errFnd ? EXIT_FAILURE : EXIT_SUCCESS);
}

2. 동작 모습

3. 디버깅 및 분석

3. tlpi-dist/dirs_links/list_files.c

1. 코드

/* list_files.c

   Demonstrate the use of opendir() and related functions to list files
   in a directory.

   Walk through each directory named on the command line (current directory
   if none are specified) to display a list of the files it contains.

    Usage: list_files [dir...]
*/
#if defined(__APPLE__)
        /* Darwin requires this header before including <dirent.h> */
#include <sys/types.h>
#endif
#include <dirent.h>
#include "tlpi_hdr.h"

static void             /* List all files in directory 'dirpath' */
listFiles(const char *dirpath)
{
    DIR *dirp;
    struct dirent *dp;
    Boolean isCurrent;          /* True if 'dirpath' is "." */

    isCurrent = strcmp(dirpath, ".") == 0;

    dirp = opendir(dirpath);
    if (dirp  == NULL) {
        errMsg("opendir failed on '%s'", dirpath);
        return;
    }

    /* For each entry in this directory, print directory + filename */

    for (;;) {
        errno = 0;              /* To distinguish error from end-of-directory */
        dp = readdir(dirp);
        if (dp == NULL)
            break;

        if (strcmp(dp->d_name, ".") == 0 || strcmp(dp->d_name, "..") == 0)
            continue;           /* Skip . and .. */

        if (!isCurrent)
            printf("%s/", dirpath);
        printf("%s\n", dp->d_name);
    }

    if (errno != 0)
        errExit("readdir");

    if (closedir(dirp) == -1)
        errMsg("closedir");
}

int
main(int argc, char *argv[])
{
    if (argc > 1 && strcmp(argv[1], "--help") == 0)
        usageErr("%s [dir-path...]\n", argv[0]);

    if (argc == 1)              /* No arguments - use current directory */
        listFiles(".");
    else
        for (argv++; *argv; argv++)
            listFiles(*argv);

    exit(EXIT_SUCCESS);
}

2. 동작 모습

3. 디버깅 및 분석

4. tlpi-dist/inotify/demo_inotify.c

1. 코드

/* demo_inotify.c

   Demonstrate the use of the inotify API.

   Usage: demo_inotify pathname...

   The program monitors each of the files specified on the command line for all
   possible file events.

   This program is Linux-specific. The inotify API is available in Linux 2.6.13
   and later.
*/
#include <sys/inotify.h>
#include <limits.h>
#include "tlpi_hdr.h"

static void             /* Display information from inotify_event structure */
displayInotifyEvent(struct inotify_event *i)
{
    printf("    wd =%2d; ", i->wd);
    if (i->cookie > 0)
        printf("cookie =%4d; ", i->cookie);

    printf("mask = ");
    if (i->mask & IN_ACCESS)        printf("IN_ACCESS ");
    if (i->mask & IN_ATTRIB)        printf("IN_ATTRIB ");
    if (i->mask & IN_CLOSE_NOWRITE) printf("IN_CLOSE_NOWRITE ");
    if (i->mask & IN_CLOSE_WRITE)   printf("IN_CLOSE_WRITE ");
    if (i->mask & IN_CREATE)        printf("IN_CREATE ");
    if (i->mask & IN_DELETE)        printf("IN_DELETE ");
    if (i->mask & IN_DELETE_SELF)   printf("IN_DELETE_SELF ");
    if (i->mask & IN_IGNORED)       printf("IN_IGNORED ");
    if (i->mask & IN_ISDIR)         printf("IN_ISDIR ");
    if (i->mask & IN_MODIFY)        printf("IN_MODIFY ");
    if (i->mask & IN_MOVE_SELF)     printf("IN_MOVE_SELF ");
    if (i->mask & IN_MOVED_FROM)    printf("IN_MOVED_FROM ");
    if (i->mask & IN_MOVED_TO)      printf("IN_MOVED_TO ");
    if (i->mask & IN_OPEN)          printf("IN_OPEN ");
    if (i->mask & IN_Q_OVERFLOW)    printf("IN_Q_OVERFLOW ");
    if (i->mask & IN_UNMOUNT)       printf("IN_UNMOUNT ");
    printf("\n");

    if (i->len > 0)
        printf("        name = %s\n", i->name);
}

#define BUF_LEN (10 * (sizeof(struct inotify_event) + NAME_MAX + 1))

int
main(int argc, char *argv[])
{
    int inotifyFd, wd, j;
    char buf[BUF_LEN] __attribute__ ((aligned(8)));
    ssize_t numRead;
    char *p;
    struct inotify_event *event;

    if (argc < 2 || strcmp(argv[1], "--help") == 0)
        usageErr("%s pathname...\n", argv[0]);

    inotifyFd = inotify_init();                 /* Create inotify instance */
    if (inotifyFd == -1)
        errExit("inotify_init");

    /* For each command-line argument, add a watch for all events */

    for (j = 1; j < argc; j++) {
        wd = inotify_add_watch(inotifyFd, argv[j], IN_ALL_EVENTS);
        if (wd == -1)
            errExit("inotify_add_watch");

        printf("Watching %s using wd %d\n", argv[j], wd);
    }

    for (;;) {                                  /* Read events forever */
        numRead = read(inotifyFd, buf, BUF_LEN);
        if (numRead == 0)
            fatal("read() from inotify fd returned 0!");

        if (numRead == -1)
            errExit("read");

        printf("Read %ld bytes from inotify fd\n", (long) numRead);

        /* Process all of the events in buffer returned by read() */

        for (p = buf; p < buf + numRead; ) {
            event = (struct inotify_event *) p;
            displayInotifyEvent(event);

            p += sizeof(struct inotify_event) + event->len;
        }
    }

    exit(EXIT_SUCCESS);
}

2. 동작 모습

3. 디버깅 및 분석