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Impl. handling symbolic links
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Stephen Seo 2024-07-04 14:48:56 +09:00
parent 20cb6cb3aa
commit 58269d751c
4 changed files with 120 additions and 17 deletions
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2
src/helpers.h
View file

@ -19,6 +19,8 @@
#ifndef SEODISPARATE_COM_SIMPLE_ARCHIVER_HELPERS_H_
#define SEODISPARATE_COM_SIMPLE_ARCHIVER_HELPERS_H_
static const unsigned int MAX_SYMBOLIC_LINK_SIZE = 512;
/// Returns non-zero if this system is big-endian.
int simple_archiver_helper_is_big_endian(void);

9
src/main.c
View file

@ -21,8 +21,13 @@
#include "parser.h"
int print_list_fn(void *data, __attribute__((unused)) void *ud) {
const char *cstr = data;
printf(" %s\n", cstr);
const SDArchiverFileInfo *file_info = data;
if (file_info->link_dest == NULL) {
printf(" REGULAR FILE: %s\n", file_info->filename);
} else {
printf(" SYMBOLIC LINK: %s -> %s\n", file_info->filename,
file_info->link_dest);
}
return 0;
}

119
src/parser.c
View file

@ -30,10 +30,12 @@
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#endif
#include "data_structures/hash_map.h"
#include "data_structures/linked_list.h"
#include "helpers.h"
#include "parser_internal.h"
/// Gets the first non "./"-like character in the filename.
@ -87,6 +89,34 @@ unsigned int simple_archiver_parser_internal_filename_idx(
return idx;
}
void simple_archiver_parser_internal_remove_end_slash(char *filename) {
int len = strlen(filename);
int idx;
for (idx = len; idx-- > 0;) {
if (filename[idx] != '/') {
++idx;
break;
}
}
if (idx < len && idx > 0) {
filename[idx] = 0;
}
}
void simple_archiver_internal_free_file_info_fn(void *data) {
SDArchiverFileInfo *file_info = data;
if (file_info) {
if (file_info->filename) {
free(file_info->filename);
}
if (file_info->link_dest) {
free(file_info->link_dest);
}
}
free(data);
}
int list_get_last_fn(void *data, void *ud) {
char **last = ud;
*last = data;
@ -188,6 +218,7 @@ int simple_archiver_parse_args(int argc, const char **argv,
int arg_length = strlen(argv[0] + arg_idx) + 1;
out->working_files[0] = malloc(arg_length);
strncpy(out->working_files[0], argv[0] + arg_idx, arg_length);
simple_archiver_parser_internal_remove_end_slash(out->working_files[0]);
out->working_files[1] = NULL;
} else {
int working_size = 1;
@ -209,6 +240,8 @@ int simple_archiver_parse_args(int argc, const char **argv,
// Set last element to the arg.
out->working_files[working_size - 1] = malloc(size);
strncpy(out->working_files[working_size - 1], argv[0] + arg_idx, size);
simple_archiver_parser_internal_remove_end_slash(
out->working_files[working_size - 1]);
}
}
@ -256,16 +289,36 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX
for (char **iter = parsed->working_files; iter && *iter; ++iter) {
struct stat st;
memset(&st, 0, sizeof(struct stat));
fstatat(AT_FDCWD, *iter, &st, AT_SYMLINK_NOFOLLOW);
if ((st.st_mode & S_IFMT) == S_IFLNK) {
// Is a symbolic link. TODO handle this.
} else if ((st.st_mode & S_IFMT) == S_IFREG) {
// Is a regular file.
if ((st.st_mode & S_IFMT) == S_IFREG || (st.st_mode & S_IFMT) == S_IFLNK) {
// Is a regular file or a symbolic link.
int len = strlen(*iter) + 1;
char *filename = malloc(len);
strncpy(filename, *iter, len);
if (simple_archiver_hash_map_get(hash_map, filename, len - 1) == NULL) {
simple_archiver_list_add(files_list, filename, NULL);
SDArchiverFileInfo *file_info = malloc(sizeof(SDArchiverFileInfo));
file_info->filename = filename;
if ((st.st_mode & S_IFMT) == S_IFLNK) {
file_info->link_dest = malloc(MAX_SYMBOLIC_LINK_SIZE);
ssize_t count = readlinkat(AT_FDCWD, filename, file_info->link_dest,
MAX_SYMBOLIC_LINK_SIZE - 1);
if (count >= MAX_SYMBOLIC_LINK_SIZE - 1) {
file_info->link_dest[MAX_SYMBOLIC_LINK_SIZE - 1] = 0;
} else if (count > 0) {
file_info->link_dest[count] = 0;
} else {
// Failure.
free(file_info->link_dest);
free(file_info);
free(filename);
continue;
}
} else {
file_info->link_dest = NULL;
}
simple_archiver_list_add(files_list, file_info,
simple_archiver_internal_free_file_info_fn);
simple_archiver_hash_map_insert(&hash_map, &hash_map_sentinel, filename,
len - 1, container_no_free_fn,
container_no_free_fn);
@ -297,14 +350,48 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
char *combined_path = malloc(combined_size);
snprintf(combined_path, combined_size, "%s/%s", next,
dir_entry->d_name);
unsigned int valid_idx =
simple_archiver_parser_internal_filename_idx(combined_path);
if (valid_idx > 0) {
char *new_path = malloc(combined_size - valid_idx);
strncpy(new_path, combined_path + valid_idx,
combined_size - valid_idx);
free(combined_path);
combined_path = new_path;
combined_size -= valid_idx;
}
memset(&st, 0, sizeof(struct stat));
fstatat(AT_FDCWD, combined_path, &st, AT_SYMLINK_NOFOLLOW);
if ((st.st_mode & S_IFMT) == S_IFLNK) {
// Is a symbolic link. TODO handle this.
} else if ((st.st_mode & S_IFMT) == S_IFREG) {
// Is a file.
if ((st.st_mode & S_IFMT) == S_IFREG ||
(st.st_mode & S_IFMT) == S_IFLNK) {
// Is a file or a symbolic link.
if (simple_archiver_hash_map_get(hash_map, combined_path,
combined_size - 1) == NULL) {
simple_archiver_list_add(files_list, combined_path, NULL);
SDArchiverFileInfo *file_info =
malloc(sizeof(SDArchiverFileInfo));
file_info->filename = combined_path;
if ((st.st_mode & S_IFMT) == S_IFLNK) {
file_info->link_dest = malloc(MAX_SYMBOLIC_LINK_SIZE);
ssize_t count =
readlinkat(AT_FDCWD, combined_path, file_info->link_dest,
MAX_SYMBOLIC_LINK_SIZE - 1);
if (count >= MAX_SYMBOLIC_LINK_SIZE - 1) {
file_info->link_dest[MAX_SYMBOLIC_LINK_SIZE - 1] = 0;
} else if (count > 0) {
file_info->link_dest[count] = 0;
} else {
// Failure.
free(file_info->link_dest);
free(file_info);
free(combined_path);
continue;
}
} else {
file_info->link_dest = NULL;
}
simple_archiver_list_add(
files_list, file_info,
simple_archiver_internal_free_file_info_fn);
simple_archiver_hash_map_insert(
&hash_map, &hash_map_sentinel, combined_path,
combined_size - 1, container_no_free_fn,
@ -336,13 +423,15 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
// Remove leading "./" entries from files_list.
for (SDArchiverLLNode *iter = files_list->head->next;
iter != files_list->tail; iter = iter->next) {
unsigned int idx = simple_archiver_parser_internal_filename_idx(iter->data);
SDArchiverFileInfo *file_info = iter->data;
unsigned int idx =
simple_archiver_parser_internal_filename_idx(file_info->filename);
if (idx > 0) {
int len = strlen((char *)iter->data) + 1 - idx;
int len = strlen(file_info->filename) + 1 - idx;
char *substr = malloc(len);
strncpy(substr, (char *)iter->data + idx, len);
free(iter->data);
iter->data = substr;
strncpy(substr, file_info->filename + idx, len);
free(file_info->filename);
file_info->filename = substr;
}
}

7
src/parser.h
View file

@ -38,6 +38,12 @@ typedef struct SDArchiverParsed {
char **working_files;
} SDArchiverParsed;
typedef struct SDArchiverFileInfo {
char *filename;
/// Is NULL if not a symbolic link.
char *link_dest;
} SDArchiverFileInfo;
void simple_archiver_print_usage(void);
SDArchiverParsed simple_archiver_create_parsed(void);
@ -50,6 +56,7 @@ int simple_archiver_parse_args(int argc, const char **argv,
void simple_archiver_free_parsed(SDArchiverParsed *parsed);
/// Each entry in the linked list is an SDArchiverFileInfo object.
SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
const SDArchiverParsed *parsed);