ls.c revision 4f6e8d7a00cbeda1e70cc15be9c4af1018bdad53 
1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <sys/types.h>
5#include <dirent.h>
6#include <errno.h>
7
8#include <sys/stat.h>
9#include <unistd.h>
10#include <time.h>
11
12#include <pwd.h>
13#include <grp.h>
14
15#include <linux/kdev_t.h>
16
17// bits for flags argument
18#define LIST_LONG       (1 << 0)
19#define LIST_ALL        (1 << 1)
20#define LIST_RECURSIVE  (1 << 2)
21
22// fwd
23static int listpath(const char *name, int flags);
24
25static char mode2kind(unsigned mode)
26{
27    switch(mode & S_IFMT){
28    case S_IFSOCK: return 's';
29    case S_IFLNK: return 'l';
30    case S_IFREG: return '-';
31    case S_IFDIR: return 'd';
32    case S_IFBLK: return 'b';
33    case S_IFCHR: return 'c';
34    case S_IFIFO: return 'p';
35    default: return '?';
36    }
37}
38
39static void mode2str(unsigned mode, char *out)
40{
41    *out++ = mode2kind(mode);
42
43    *out++ = (mode & 0400) ? 'r' : '-';
44    *out++ = (mode & 0200) ? 'w' : '-';
45    if(mode & 04000) {
46        *out++ = (mode & 0100) ? 's' : 'S';
47    } else {
48        *out++ = (mode & 0100) ? 'x' : '-';
49    }
50    *out++ = (mode & 040) ? 'r' : '-';
51    *out++ = (mode & 020) ? 'w' : '-';
52    if(mode & 02000) {
53        *out++ = (mode & 010) ? 's' : 'S';
54    } else {
55        *out++ = (mode & 010) ? 'x' : '-';
56    }
57    *out++ = (mode & 04) ? 'r' : '-';
58    *out++ = (mode & 02) ? 'w' : '-';
59    if(mode & 01000) {
60        *out++ = (mode & 01) ? 't' : 'T';
61    } else {
62        *out++ = (mode & 01) ? 'x' : '-';
63    }
64    *out = 0;
65}
66
67static void user2str(unsigned uid, char *out)
68{
69    struct passwd *pw = getpwuid(uid);
70    if(pw) {
71        strcpy(out, pw->pw_name);
72    } else {
73        sprintf(out, "%d", uid);
74    }
75}
76
77static void group2str(unsigned gid, char *out)
78{
79    struct group *gr = getgrgid(gid);
80    if(gr) {
81        strcpy(out, gr->gr_name);
82    } else {
83        sprintf(out, "%d", gid);
84    }
85}
86
87static int listfile(const char *path, int flags)
88{
89    struct stat s;
90    char date[32];
91    char mode[16];
92    char user[16];
93    char group[16];
94    const char *name;
95
96    /* name is anything after the final '/', or the whole path if none*/
97    name = strrchr(path, '/');
98    if(name == 0) {
99        name = path;
100    } else {
101        name++;
102    }
103
104    if(lstat(path, &s) < 0) {
105        return -1;
106    }
107
108    mode2str(s.st_mode, mode);
109    user2str(s.st_uid, user);
110    group2str(s.st_gid, group);
111
112    strftime(date, 32, "%Y-%m-%d %H:%M", localtime((const time_t*)&s.st_mtime));
113    date[31] = 0;
114
115// 12345678901234567890123456789012345678901234567890123456789012345678901234567890
116// MMMMMMMM UUUUUUUU GGGGGGGGG XXXXXXXX YYYY-MM-DD HH:MM NAME (->LINK)
117
118    switch(s.st_mode & S_IFMT) {
119    case S_IFBLK:
120    case S_IFCHR:
121        printf("%s %-8s %-8s %3d, %3d %s %s\n",
122               mode, user, group,
123               (int) MAJOR(s.st_rdev), (int) MINOR(s.st_rdev),
124               date, name);
125        break;
126    case S_IFREG:
127        printf("%s %-8s %-8s %8d %s %s\n",
128               mode, user, group, (int) s.st_size, date, name);
129        break;
130    case S_IFLNK: {
131        char linkto[256];
132        int len;
133
134        len = readlink(path, linkto, 256);
135        if(len < 0) return -1;
136
137        if(len > 255) {
138            linkto[252] = '.';
139            linkto[253] = '.';
140            linkto[254] = '.';
141            linkto[255] = 0;
142        } else {
143            linkto[len] = 0;
144        }
145
146        printf("%s %-8s %-8s          %s %s -> %s\n",
147               mode, user, group, date, name, linkto);
148        break;
149    }
150    default:
151        printf("%s %-8s %-8s          %s %s\n",
152               mode, user, group, date, name);
153
154    }
155    return 0;
156}
157
158static int listdir(const char *name, int flags)
159{
160    char tmp[4096];
161    DIR *d;
162    struct dirent *de;
163
164    d = opendir(name);
165    if(d == 0) {
166        fprintf(stderr, "opendir failed, %s\n", strerror(errno));
167        return -1;
168    }
169
170    while((de = readdir(d)) != 0){
171        if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
172        if(de->d_name[0] == '.' && (flags & LIST_ALL) == 0) continue;
173        if ((flags & LIST_LONG) != 0) {
174            sprintf(tmp, "%s/%s", name, de->d_name);
175            listfile(tmp, flags);
176        } else {
177            printf("%s\n", de->d_name);
178        }
179    }
180
181    if (flags & LIST_RECURSIVE) {
182        rewinddir(d);
183
184        while ((de = readdir(d)) != 0) {
185            struct stat s;
186            int err;
187
188            if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
189                continue;
190            if (de->d_name[0] == '.' && (flags & LIST_ALL) == 0)
191                continue;
192
193            if (!strcmp(name, "/")) sprintf(tmp, "/%s", de->d_name);
194            else sprintf(tmp, "%s/%s", name, de->d_name);
195
196            /*
197             * If the name ends in a '/', use stat() so we treat it like a
198             * directory even if it's a symlink.
199             */
200            if (tmp[strlen(tmp)-1] == '/')
201                err = stat(tmp, &s);
202            else
203                err = lstat(tmp, &s);
204
205            if (err < 0) {
206                perror(tmp);
207                closedir(d);
208                return -1;
209            }
210
211            if (S_ISDIR(s.st_mode)) {
212                printf("\n%s:\n", tmp);
213                listdir(tmp, flags);
214            }
215        }
216    }
217
218    closedir(d);
219    return 0;
220}
221
222static int listpath(const char *name, int flags)
223{
224    struct stat s;
225    int err;
226
227    /*
228     * If the name ends in a '/', use stat() so we treat it like a
229     * directory even if it's a symlink.
230     */
231    if (name[strlen(name)-1] == '/')
232        err = stat(name, &s);
233    else
234        err = lstat(name, &s);
235
236    if (err < 0) {
237        perror(name);
238        return -1;
239    }
240
241    if (S_ISDIR(s.st_mode)) {
242        if (flags & LIST_RECURSIVE)
243            printf("\n%s:\n", name);
244        return listdir(name, flags);
245    } else {
246        if ((flags & LIST_LONG) != 0) {
247            /* yeah this calls stat() again*/
248            return listfile(name, flags);
249        } else {
250            printf("%s\n", name);
251            return 0;
252        }
253    }
254}
255
256int ls_main(int argc, char **argv)
257{
258    int flags = 0;
259    int listed = 0;
260
261    if(argc > 1) {
262        int i;
263        int err = 0;
264
265        for (i = 1; i < argc; i++) {
266            if(!strcmp(argv[i], "-l")) {
267                flags |= LIST_LONG;
268            } else if (!strcmp(argv[i], "-a")) {
269                flags |= LIST_ALL;
270            } else if (!strcmp(argv[i], "-R")) {
271                flags |= LIST_RECURSIVE;
272            } else {
273                listed++;
274                if(listpath(argv[i], flags) != 0) {
275                    err = EXIT_FAILURE;
276                }
277            }
278        }
279
280        if (listed  > 0) return err;
281    }
282
283    // list working directory if no files or directories were specified
284    return listpath(".", flags);
285}
286