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#include <stdio.h>
#include <stdlib.h>
#include <dirent.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#define STAT_ISSET(mode, mask) (((mode) & mask) == mask)
static size_t max_linksiz = 128;
static int max_nlinks = 1;
static int max_size = 1;
static int max_uid = 1;
static int max_gid = 1;
static int max_min = 1;
static int max_maj = 1;
static void do_preformat(const struct stat *st)
{
int bytes;
bytes = snprintf(NULL, 0, "%ju", (uintmax_t) st->st_nlink);
if (bytes > max_nlinks)
max_nlinks = bytes;
bytes = snprintf(NULL, 0, "%ju", (uintmax_t) st->st_uid);
if (bytes > max_uid)
max_uid = bytes;
bytes = snprintf(NULL, 0, "%ju", (uintmax_t) st->st_gid);
if (bytes > max_gid)
max_gid = bytes;
if (S_ISCHR(st->st_mode) || S_ISBLK(st->st_mode)) {
bytes = snprintf(NULL, 0, "%u", major(st->st_rdev));
if (bytes > max_maj)
max_maj = bytes;
bytes = snprintf(NULL, 0, "%u", minor(st->st_rdev));
if (bytes > max_min)
max_min = bytes;
max_size = max_maj + max_min + 1;
} else {
bytes = snprintf(NULL, 0, "%ju", (uintmax_t) st->st_size);
if (bytes > max_size)
max_size = bytes;
}
return;
}
static void do_stat(const struct stat *st, int dir_fd, const char *path)
{
char *fmt, *link_name;
int rc;
switch (st->st_mode & S_IFMT) {
case S_IFBLK:
putchar('b');
break;
case S_IFCHR:
putchar('c');
break;
case S_IFDIR:
putchar('d');
break;
case S_IFIFO:
putchar('p');
break;
case S_IFLNK:
putchar('l');
break;
case S_IFSOCK:
putchar('s');
break;
case S_IFREG:
putchar('-');
break;
default:
putchar('?');
break;
}
putchar(STAT_ISSET(st->st_mode, S_IRUSR) ? 'r' : '-');
putchar(STAT_ISSET(st->st_mode, S_IWUSR) ? 'w' : '-');
!STAT_ISSET(st->st_mode, S_ISUID) ?
putchar(STAT_ISSET(st->st_mode, S_IXUSR) ? 'x' : '-') :
putchar('S');
putchar(STAT_ISSET(st->st_mode, S_IRGRP) ? 'r' : '-');
putchar(STAT_ISSET(st->st_mode, S_IWGRP) ? 'w' : '-');
!STAT_ISSET(st->st_mode, S_ISGID) ?
putchar(STAT_ISSET(st->st_mode, S_IXGRP) ? 'x' : '-') :
putchar('S');
putchar(STAT_ISSET(st->st_mode, S_IROTH) ? 'r' : '-');
putchar(STAT_ISSET(st->st_mode, S_IWOTH) ? 'w' : '-');
!STAT_ISSET(st->st_mode, S_ISVTX) ?
putchar(STAT_ISSET(st->st_mode, S_IXOTH) ? 'x' : '-') :
putchar(S_ISDIR(st->st_mode) ? 't' : 'T');
if (S_ISCHR(st->st_mode) || S_ISBLK(st->st_mode)) {
rc = asprintf(&fmt, " %%%dju %%%dju %%%dju %%%du,%%%du %%s",
max_nlinks, max_uid, max_gid, max_maj, max_min);
if (rc == -1) {
perror("asprintf");
exit(1);
}
fprintf(stdout, fmt,
(uintmax_t) st->st_nlink,
(uintmax_t) st->st_uid,
(uintmax_t) st->st_gid,
major(st->st_rdev),
minor(st->st_rdev),
path);
} else {
rc = asprintf(&fmt, " %%%dju %%%dju %%%dju %%%dju %%s",
max_nlinks, max_uid, max_gid, max_size);
if (rc == -1) {
perror("asprintf");
exit(1);
}
fprintf(stdout, fmt,
(uintmax_t) st->st_nlink,
(uintmax_t) st->st_uid,
(uintmax_t) st->st_gid,
(uintmax_t) st->st_size,
path);
}
free(fmt);
if (S_ISLNK(st->st_mode)) {
link_name = malloc(max_linksiz);
if (link_name == NULL) {
perror("malloc");
exit(1);
}
rc = readlinkat(dir_fd, path, link_name, max_linksiz);
if (rc == -1) {
free(link_name);
perror("readlink");
exit(1);
}
link_name[rc] = '\0';
fprintf(stdout, " -> %s", link_name);
free(link_name);
}
putchar('\n');
return;
}
static void do_dir(const char *path, int preformat)
{
DIR *dir;
int dir_fd;
struct dirent *dent;
struct stat st;
dir = opendir(path);
if (dir == NULL) {
perror(path);
exit(1);
}
dir_fd = dirfd(dir);
while ((dent = readdir(dir)) != NULL) {
if (fstatat(dir_fd, dent->d_name, &st,
AT_SYMLINK_NOFOLLOW)) {
perror(dent->d_name);
exit(1);
}
(preformat) ?
do_preformat(&st) :
do_stat(&st, dir_fd, dent->d_name);
}
closedir(dir);
}
int main(int argc, char *argv[])
{
int i;
struct stat st;
if (argc == 1) {
do_dir(".", 1);
do_dir(".", 0);
return 0;
}
for (i = 1; i < argc; i++) {
if (argv[i][0] == '-' && argv[i][1] == 'h') {
fprintf(stdout, "Usage: ls [-h] [FILE ...]\n");
return 0;
}
if (lstat(argv[i], &st)) {
perror(argv[i]);
exit(1);
}
S_ISDIR(st.st_mode) ?
do_dir(argv[i], 1) :
do_preformat(&st);
}
for (i = 1; i < argc; i++) {
if (lstat(argv[i], &st)) {
perror(argv[i]);
exit(1);
}
S_ISDIR(st.st_mode) ?
do_dir(argv[i], 0) :
do_stat(&st, AT_FDCWD, argv[i]);
}
return 0;
}
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