Add NULL check when printing cwd on temp file fail

Also some minor changes like more error logs and refactorings.

README.md

@@ -18,6 +18,8 @@ API calls.
     -t : examine archive file
     -f <filename> : filename to work on
       Use "-f -" to work on stdout when creating archive or stdin when reading archive
+      NOTICE: "-f" is not affected by "-C"!
+    -C <dir> : Change current working directory before archiving/extracting
     --compressor <full_compress_cmd> : requires --decompressor
     --decompressor <full_decompress_cmd> : requires --compressor
       Specifying "--decompressor" when extracting overrides archive file's stored decompressor cmd

src/archiver.c

@@ -40,6 +40,8 @@
 #include "helpers.h"
 
 #define TEMP_FILENAME_CMP "%s%ssimple_archiver_compressed_%u.tmp"
+#define FILE_COUNTS_OUTPUT_FORMAT_STR_0 "\nFile %%%uu of %%%uu.\n"
+#define FILE_COUNTS_OUTPUT_FORMAT_STR_1 "[%%%uu/%%%uu]\n"
 
 #if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN || \
     SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||          \
@@ -200,6 +202,19 @@ int write_files_fn(void *data, void *ud) {
           fopen(temp_filename, "wb");
       if (!tmp_fd) {
         fprintf(stderr, "ERROR: Unable to create temp file for compressing!\n");
+#if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN || \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||          \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX
+        __attribute__((cleanup(free_malloced_memory))) void *real_cwd =
+            realpath(".", NULL);
+        if (real_cwd) {
+          fprintf(stderr, "Tried to create temp file(s) in \"%s\"!\n",
+                  (char *)real_cwd);
+        }
+#endif
+        fprintf(stderr,
+                "(Use \"--temp-files-dir <dir>\" to change where to write temp "
+                "files.)\n");
         return 1;
       }
       __attribute__((cleanup(cleanup_temp_filename_delete))) void **ptrs_array =
@@ -543,6 +558,8 @@ int write_files_fn(void *data, void *ud) {
       int stat_fd = open(file_info->filename, O_RDONLY);
       if (stat_fd == -1) {
         // Error.
+        fprintf(stderr, "ERROR: Failed to get stat of \"%s\"!\n",
+                file_info->filename);
         return 1;
       }
       int stat_status = fstat(stat_fd, &stat_buf);
@@ -866,16 +883,45 @@ int write_files_fn(void *data, void *ud) {
     simple_archiver_list_free(&to_write);
   }
 
-  fprintf(stderr, "[%10u/%10u]\n", ++(state->count), state->max);
+  char format_str[64];
+  snprintf(format_str, 64, FILE_COUNTS_OUTPUT_FORMAT_STR_1, state->digits,
+           state->digits);
+  fprintf(stderr, format_str, ++(state->count), state->max);
   return 0;
 }
 
 void cleanup_nop_fn(__attribute__((unused)) void *unused) {}
 void cleanup_free_fn(void *data) { free(data); }
 
+void simple_archiver_internal_chdir_back2(char **original) {
+  if (original && *original) {
+#if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX || \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||   \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN
+    chdir(*original);
+#endif
+    free(*original);
+    *original = NULL;
+  }
+}
+
 int filenames_to_abs_map_fn(void *data, void *ud) {
   SDArchiverFileInfo *file_info = data;
-  SDArchiverHashMap **abs_filenames = ud;
+  void **ptr_array = ud;
+  SDArchiverHashMap **abs_filenames = ptr_array[0];
+  const char *user_cwd = ptr_array[1];
+  __attribute__((
+      cleanup(simple_archiver_internal_chdir_back2))) char *original_cwd = NULL;
+  if (user_cwd) {
+#if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN || \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||          \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX
+    original_cwd = realpath(".", NULL);
+    if (chdir(user_cwd)) {
+      return 1;
+    }
+#endif
+  }
 
   // Get combined full path to file.
   char *fullpath = filename_to_absolute_path(file_info->filename);
@@ -897,6 +943,7 @@ int filenames_to_abs_map_fn(void *data, void *ud) {
   if (!cwd_dirname) {
     return 1;
   }
+  // fprintf(stderr, "cwd_dirname: %s\n", (char*)cwd_dirname);
 
   // Use copy of fullpath to avoid clobbering it.
   __attribute__((cleanup(free_malloced_memory))) void *fullpath_copy =
@@ -947,6 +994,8 @@ char *simple_archiver_error_to_string(enum SDArchiverStateReturns error) {
       return "Failed to create set of filenames (internal error)";
     case SDAS_FAILED_TO_EXTRACT_SYMLINK:
       return "Failed to extract symlink (internal error)";
+    case SDAS_FAILED_TO_CHANGE_CWD:
+      return "Failed to change current working directory";
     default:
       return "Unknown error";
   }
@@ -962,6 +1011,9 @@ SDArchiverState *simple_archiver_init_state(const SDArchiverParsed *parsed) {
   state->parsed = parsed;
   state->out_f = NULL;
   state->map = NULL;
+  state->count = 0;
+  state->max = 0;
+  state->digits = 10;
 
   return state;
 }
@@ -978,10 +1030,14 @@ int simple_archiver_write_all(FILE *out_f, SDArchiverState *state,
   // First create a "set" of absolute paths to given filenames.
   __attribute__((cleanup(simple_archiver_hash_map_free)))
   SDArchiverHashMap *abs_filenames = simple_archiver_hash_map_init();
-  if (simple_archiver_list_get(filenames, filenames_to_abs_map_fn,
-                               &abs_filenames)) {
+  void **ptr_array = malloc(sizeof(void *) * 2);
+  ptr_array[0] = &abs_filenames;
+  ptr_array[1] = (void *)state->parsed->user_cwd;
+  if (simple_archiver_list_get(filenames, filenames_to_abs_map_fn, ptr_array)) {
+    free(ptr_array);
     return SDAS_FAILED_TO_CREATE_MAP;
   }
+  free(ptr_array);
 
   if (fwrite("SIMPLE_ARCHIVE_VER", 1, 18, out_f) != 18) {
     return SDAS_FAILED_TO_WRITE;
@@ -1067,8 +1123,24 @@ int simple_archiver_write_all(FILE *out_f, SDArchiverState *state,
   state->max = filenames->count;
   state->out_f = out_f;
   state->map = abs_filenames;
+  state->digits = simple_archiver_helper_num_digits(state->max);
   fprintf(stderr, "Begin archiving...\n");
-  fprintf(stderr, "[%10u/%10u]\n", state->count, state->max);
+  __attribute__((
+      cleanup(simple_archiver_internal_chdir_back2))) char *original_cwd = NULL;
+  if (state->parsed->user_cwd) {
+#if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN || \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||          \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX
+    original_cwd = realpath(".", NULL);
+    if (chdir(state->parsed->user_cwd)) {
+      return 1;
+    }
+#endif
+  }
+  char format_str[64];
+  snprintf(format_str, 64, FILE_COUNTS_OUTPUT_FORMAT_STR_1, state->digits,
+           state->digits);
+  fprintf(stderr, format_str, state->count, state->max);
   if (simple_archiver_list_get(filenames, write_files_fn, state)) {
     // Error occurred.
     fprintf(stderr, "Error ocurred writing file(s) to archive.\n");
@@ -1102,6 +1174,16 @@ int simple_archiver_parse_archive_info(FILE *in_f, int do_extract,
     return SDAS_INVALID_FILE;
   }
 
+  if (do_extract && state->parsed->user_cwd) {
+#if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN || \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||          \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX
+    if (chdir(state->parsed->user_cwd)) {
+      return SDAS_FAILED_TO_CHANGE_CWD;
+    }
+#endif
+  }
+
   __attribute__((cleanup(free_malloced_memory))) void *decompressor_cmd = NULL;
 
   if ((buf[0] & 1) != 0) {
@@ -1166,7 +1248,10 @@ int simple_archiver_parse_archive_info(FILE *in_f, int do_extract,
   simple_archiver_helper_32_bit_be(&u32);
   fprintf(stderr, "File count is %u\n", u32);
 
-  uint32_t size = u32;
+  const uint32_t size = u32;
+  const unsigned int digits = simple_archiver_helper_num_digits(size);
+  char format_str[128];
+  snprintf(format_str, 128, FILE_COUNTS_OUTPUT_FORMAT_STR_0, digits, digits);
   int skip = 0;
   __attribute__((cleanup(simple_archiver_hash_map_free)))
   SDArchiverHashMap *hash_map = NULL;
@@ -1184,7 +1269,7 @@ int simple_archiver_parse_archive_info(FILE *in_f, int do_extract,
     }
   }
   for (uint32_t idx = 0; idx < size; ++idx) {
-    fprintf(stderr, "\nFile %10u of %10u.\n", idx + 1, size);
+    fprintf(stderr, format_str, idx + 1, size);
     if (feof(in_f) || ferror(in_f)) {
       return SDAS_INVALID_FILE;
     } else if (fread(&u16, 2, 1, in_f) != 1) {

src/archiver.h

@@ -34,6 +34,7 @@ typedef struct SDArchiverState {
   SDArchiverHashMap *map;
   unsigned int count;
   unsigned int max;
+  unsigned int digits;
 } SDArchiverState;
 
 enum SDArchiverStateReturns {
@@ -46,7 +47,8 @@ enum SDArchiverStateReturns {
   SDAS_INVALID_FILE,
   SDAS_INTERNAL_ERROR,
   SDAS_FAILED_TO_CREATE_MAP,
-  SDAS_FAILED_TO_EXTRACT_SYMLINK
+  SDAS_FAILED_TO_EXTRACT_SYMLINK,
+  SDAS_FAILED_TO_CHANGE_CWD
 };
 
 /// Returned pointer must not be freed.

src/helpers.c

@@ -191,3 +191,38 @@ int simple_archiver_helper_make_dirs(const char *file_path) {
   return 1;
 #endif
 }
+
+char *simple_archiver_helper_cut_substr(const char *s, unsigned int start_idx,
+                                        unsigned int end_idx) {
+  unsigned int s_len = strlen(s);
+  if (start_idx > end_idx || start_idx >= s_len || end_idx > s_len) {
+    return NULL;
+  } else if (end_idx == s_len) {
+    if (start_idx == 0) {
+      return NULL;
+    }
+    char *new_s = malloc(start_idx + 1);
+    strncpy(new_s, s, start_idx + 1);
+    new_s[start_idx] = 0;
+    return new_s;
+  } else if (start_idx == 0) {
+    char *new_s = malloc(s_len - end_idx + 1);
+    strncpy(new_s, s + end_idx, s_len - end_idx + 1);
+    return new_s;
+  } else {
+    char *new_s = malloc(start_idx + s_len - end_idx + 1);
+    strncpy(new_s, s, start_idx);
+    strncpy(new_s + start_idx, s + end_idx, s_len - end_idx + 1);
+    return new_s;
+  }
+}
+
+unsigned int simple_archiver_helper_num_digits(unsigned int value) {
+  unsigned int digits = 0;
+  do {
+    ++digits;
+    value /= 10;
+  } while (value != 0);
+
+  return digits;
+}

src/helpers.h

@@ -46,4 +46,12 @@ void simple_archiver_helper_cmd_string_argv_free_ptr(char ***argv_strs);
 /// Returns zero on success.
 int simple_archiver_helper_make_dirs(const char *file_path);
 
+/// Returns non-NULL on success.
+/// Must be free'd with "free()" if non-NULL.
+/// start_idx is inclusive and end_idx is exclusive.
+char *simple_archiver_helper_cut_substr(const char *s, unsigned int start_idx,
+                                        unsigned int end_idx);
+
+unsigned int simple_archiver_helper_num_digits(unsigned int value);
+
 #endif

src/main.c

@@ -70,6 +70,11 @@ int main(int argc, const char **argv) {
   __attribute__((cleanup(simple_archiver_list_free)))
   SDArchiverLinkedList *filenames =
       simple_archiver_parsed_to_filenames(&parsed);
+  if (!filenames) {
+    fprintf(stderr,
+            "ERROR: Failed to resolve filenames from positional arguments!\n");
+    return 8;
+  }
 
   if (filenames->count > 0) {
     fprintf(stderr, "Filenames:\n");

src/parser.c

@@ -39,7 +39,7 @@
 #include "parser_internal.h"
 
 /// Gets the first non "./"-like character in the filename.
-unsigned int simple_archiver_parser_internal_filename_idx(
+unsigned int simple_archiver_parser_internal_get_first_non_current_idx(
     const char *filename) {
   unsigned int idx = 0;
   unsigned int known_good_idx = 0;
@@ -103,6 +103,18 @@ void simple_archiver_parser_internal_remove_end_slash(char *filename) {
   }
 }
 
+void simple_archiver_internal_chdir_back(char **original) {
+  if (original && *original) {
+#if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX || \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||   \
+    SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN
+    chdir(*original);
+#endif
+    free(*original);
+    *original = NULL;
+  }
+}
+
 void simple_archiver_internal_free_file_info_fn(void *data) {
   SDArchiverFileInfo *file_info = data;
   if (file_info) {
@@ -142,6 +154,10 @@ void simple_archiver_print_usage(void) {
   fprintf(stderr,
           "  Use \"-f -\" to work on stdout when creating archive or stdin "
           "when reading archive\n");
+  fprintf(stderr, "  NOTICE: \"-f\" is not affected by \"-C\"!\n");
+  fprintf(stderr,
+          "-C <dir> : Change current working directory before "
+          "archiving/extracting\n");
   fprintf(stderr,
           "--compressor <full_compress_cmd> : requires --decompressor\n");
   fprintf(stderr,
@@ -175,6 +191,7 @@ SDArchiverParsed simple_archiver_create_parsed(void) {
   parsed.decompressor = NULL;
   parsed.working_files = NULL;
   parsed.temp_dir = NULL;
+  parsed.user_cwd = NULL;
 
   return parsed;
 }
@@ -239,6 +256,15 @@ int simple_archiver_parse_args(int argc, const char **argv,
         }
         --argc;
         ++argv;
+      } else if (strcmp(argv[0], "-C") == 0) {
+        if (argc < 2) {
+          fprintf(stderr, "ERROR: -C specified but missing argument!\n");
+          simple_archiver_print_usage();
+          return 1;
+        }
+        out->user_cwd = argv[1];
+        --argc;
+        ++argv;
       } else if (strcmp(argv[0], "--compressor") == 0) {
         if (argc < 2) {
           fprintf(stderr, "--compressor specfied but missing argument!\n");
@@ -286,8 +312,8 @@ int simple_archiver_parse_args(int argc, const char **argv,
       if (out->working_files == NULL) {
         out->working_files = malloc(sizeof(char *) * 2);
         unsigned int arg_idx =
-            simple_archiver_parser_internal_filename_idx(argv[0]);
-        int arg_length = strlen(argv[0] + arg_idx) + 1;
+            simple_archiver_parser_internal_get_first_non_current_idx(argv[0]);
+        unsigned 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]);
@@ -307,7 +333,7 @@ int simple_archiver_parse_args(int argc, const char **argv,
         // Set new actual last element to NULL.
         out->working_files[working_size] = NULL;
         unsigned int arg_idx =
-            simple_archiver_parser_internal_filename_idx(argv[0]);
+            simple_archiver_parser_internal_get_first_non_current_idx(argv[0]);
         int size = strlen(argv[0] + arg_idx) + 1;
         // Set last element to the arg.
         out->working_files[working_size - 1] = malloc(size);
@@ -363,19 +389,31 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
 #if SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_COSMOPOLITAN || \
     SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_MAC ||          \
     SIMPLE_ARCHIVER_PLATFORM == SIMPLE_ARCHIVER_PLATFORM_LINUX
+  __attribute__((
+      cleanup(simple_archiver_internal_chdir_back))) char *original_cwd = NULL;
+  if (parsed->user_cwd) {
+    original_cwd = realpath(".", NULL);
+    if (chdir(parsed->user_cwd)) {
+      simple_archiver_list_free(&files_list);
+      return NULL;
+    }
+  }
+
   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);
+    char *file_path = *iter;
+    fstatat(AT_FDCWD, file_path, &st, AT_SYMLINK_NOFOLLOW);
     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;
+      int len = strlen(file_path) + 1;
       char *filename = malloc(len);
-      strncpy(filename, *iter, len);
+      strncpy(filename, file_path, len);
       if (simple_archiver_hash_map_get(hash_map, filename, len - 1) == NULL) {
         SDArchiverFileInfo *file_info = malloc(sizeof(SDArchiverFileInfo));
         file_info->filename = filename;
         if ((st.st_mode & S_IFMT) == S_IFLNK) {
+          // Is a symlink.
           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);
@@ -385,13 +423,35 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
             file_info->link_dest[count] = 0;
           } else {
             // Failure.
+            fprintf(stderr,
+                    "WARNING: Could not get link info for file \"%s\"!\n",
+                    file_info->filename);
             free(file_info->link_dest);
             free(file_info);
             free(filename);
             continue;
           }
         } else {
+          // Is a regular file.
           file_info->link_dest = NULL;
+          // Check that the file is readable by opening it. Easier than to
+          // check permissions because that would also require checking if the
+          // current USER can open the file.
+          FILE *readable_file = fopen(file_info->filename, "rb");
+          if (!readable_file) {
+            // Cannot open file, so it must be unreadable (at least by the
+            // current USER).
+            fprintf(stderr, "WARNING: \"%s\" is not readable, skipping!\n",
+                    file_info->filename);
+            free(file_info->link_dest);
+            free(file_info);
+            free(filename);
+            continue;
+          } else {
+            fclose(readable_file);
+            // fprintf(stderr, "DEBUG: \"%s\" is readable.\n",
+            // file_info->filename);
+          }
         }
         simple_archiver_list_add(files_list, file_info,
                                  simple_archiver_internal_free_file_info_fn);
@@ -405,7 +465,7 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
       // Is a directory.
       __attribute__((cleanup(simple_archiver_list_free)))
       SDArchiverLinkedList *dir_list = simple_archiver_list_init();
-      simple_archiver_list_add(dir_list, *iter, container_no_free_fn);
+      simple_archiver_list_add(dir_list, file_path, container_no_free_fn);
       char *next;
       while (dir_list->count != 0) {
         simple_archiver_list_get(dir_list, list_get_last_fn, &next);
@@ -428,7 +488,8 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
             snprintf(combined_path, combined_size, "%s/%s", next,
                      dir_entry->d_name);
             unsigned int valid_idx =
-                simple_archiver_parser_internal_filename_idx(combined_path);
+                simple_archiver_parser_internal_get_first_non_current_idx(
+                    combined_path);
             if (valid_idx > 0) {
               char *new_path = malloc(combined_size - valid_idx);
               strncpy(new_path, combined_path + valid_idx,
@@ -448,6 +509,7 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
                     malloc(sizeof(SDArchiverFileInfo));
                 file_info->filename = combined_path;
                 if ((st.st_mode & S_IFMT) == S_IFLNK) {
+                  // Is a symlink.
                   file_info->link_dest = malloc(MAX_SYMBOLIC_LINK_SIZE);
                   ssize_t count =
                       readlinkat(AT_FDCWD, combined_path, file_info->link_dest,
@@ -464,7 +526,27 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
                     continue;
                   }
                 } else {
+                  // Is a regular file.
                   file_info->link_dest = NULL;
+                  // Check that the file is readable by opening it. Easier than
+                  // to check permissions because that would also require
+                  // checking if the current USER can open the file.
+                  FILE *readable_file = fopen(file_info->filename, "rb");
+                  if (!readable_file) {
+                    // Cannot open file, so it must be unreadable (at least by
+                    // the current USER).
+                    fprintf(stderr,
+                            "WARNING: \"%s\" is not readable, skipping!\n",
+                            file_info->filename);
+                    free(file_info->link_dest);
+                    free(file_info);
+                    free(combined_path);
+                    continue;
+                  } else {
+                    fclose(readable_file);
+                    // fprintf(stderr, "DEBUG: \"%s\" is readable.\n",
+                    // file_info->filename);
+                  }
                 }
                 simple_archiver_list_add(
                     files_list, file_info,
@@ -497,12 +579,14 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
   }
 #endif
 
-  // Remove leading "./" entries from files_list.
   for (SDArchiverLLNode *iter = files_list->head->next;
        iter != files_list->tail; iter = iter->next) {
     SDArchiverFileInfo *file_info = iter->data;
+
+    // Remove leading "./" entries from files_list.
     unsigned int idx =
-        simple_archiver_parser_internal_filename_idx(file_info->filename);
+        simple_archiver_parser_internal_get_first_non_current_idx(
+            file_info->filename);
     if (idx > 0) {
       int len = strlen(file_info->filename) + 1 - idx;
       char *substr = malloc(len);
@@ -510,6 +594,28 @@ SDArchiverLinkedList *simple_archiver_parsed_to_filenames(
       free(file_info->filename);
       file_info->filename = substr;
     }
+
+    // Remove "./" entries inside the file path.
+    int slash_found = 0;
+    int dot_found = 0;
+    for (idx = strlen(file_info->filename); idx-- > 0;) {
+      if (file_info->filename[idx] == '/') {
+        if (dot_found) {
+          char *temp = simple_archiver_helper_cut_substr(file_info->filename,
+                                                         idx + 1, idx + 3);
+          free(file_info->filename);
+          file_info->filename = temp;
+        } else {
+          slash_found = 1;
+          continue;
+        }
+      } else if (file_info->filename[idx] == '.' && slash_found) {
+        dot_found = 1;
+        continue;
+      }
+      slash_found = 0;
+      dot_found = 0;
+    }
   }
 
   return files_list;

src/parser.h

@@ -45,6 +45,8 @@ typedef struct SDArchiverParsed {
   /// Determines where to place temporary files. If NULL, temporary files are
   /// created in the current working directory.
   const char *temp_dir;
+  /// Dir specified by "-C".
+  const char *user_cwd;
 } SDArchiverParsed;
 
 typedef struct SDArchiverFileInfo {

src/parser_internal.h

@@ -21,6 +21,7 @@
 
 #include "parser.h"
 
-unsigned int simple_archiver_parser_internal_filename_idx(const char *filename);
+unsigned int simple_archiver_parser_internal_get_first_non_current_idx(
+    const char *filename);
 
 #endif

src/test.c

@@ -57,34 +57,42 @@ static int checks_passed = 0;
 int main(void) {
   // Test parser.
   {
-    unsigned int idx = simple_archiver_parser_internal_filename_idx("test");
+    unsigned int idx =
+        simple_archiver_parser_internal_get_first_non_current_idx("test");
     CHECK_TRUE(idx == 0);
 
-    idx = simple_archiver_parser_internal_filename_idx("./test");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx("./test");
     CHECK_TRUE(idx == 2);
 
-    idx = simple_archiver_parser_internal_filename_idx("././test");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx("././test");
     CHECK_TRUE(idx == 4);
 
-    idx = simple_archiver_parser_internal_filename_idx("././//././//./test");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        "././//././//./test");
     CHECK_TRUE(idx == 14);
 
-    idx = simple_archiver_parser_internal_filename_idx("/././//././//./test");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        "/././//././//./test");
     CHECK_TRUE(idx == 0);
 
-    idx = simple_archiver_parser_internal_filename_idx(".derp/.//././//./test");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        ".derp/.//././//./test");
     CHECK_TRUE(idx == 0);
 
-    idx = simple_archiver_parser_internal_filename_idx("././/.derp/.///./test");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        "././/.derp/.///./test");
     CHECK_TRUE(idx == 5);
 
-    idx = simple_archiver_parser_internal_filename_idx("././/.//.//./");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        "././/.//.//./");
     CHECK_TRUE(idx == 11);
 
-    idx = simple_archiver_parser_internal_filename_idx("././/.//.//.");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        "././/.//.//.");
     CHECK_TRUE(idx == 11);
 
-    idx = simple_archiver_parser_internal_filename_idx("././/.//.//");
+    idx = simple_archiver_parser_internal_get_first_non_current_idx(
+        "././/.//.//");
     CHECK_TRUE(idx == 8);
 
     SDArchiverParsed parsed = simple_archiver_create_parsed();
@@ -197,6 +205,39 @@ int main(void) {
     simple_archiver_helper_cmd_string_argv_free(result_argv);
   } while (0);
 
+  // Test helpers cut substr.
+  {
+    const char *s = "one two three.";
+    unsigned int s_len = strlen(s);
+    // Invalid range.
+    char *out = simple_archiver_helper_cut_substr(s, 1, 0);
+    CHECK_FALSE(out);
+    // First idx out of range.
+    out = simple_archiver_helper_cut_substr(s, s_len, s_len + 1);
+    CHECK_FALSE(out);
+    // Second idx out of range.
+    out = simple_archiver_helper_cut_substr(s, 1, s_len + 1);
+    CHECK_FALSE(out);
+    // Invalid cut of full string.
+    out = simple_archiver_helper_cut_substr(s, 0, s_len);
+    CHECK_FALSE(out);
+    // Cut end of string.
+    out = simple_archiver_helper_cut_substr(s, 2, s_len);
+    CHECK_TRUE(out);
+    CHECK_STREQ(out, "on");
+    free(out);
+    // Cut start of string.
+    out = simple_archiver_helper_cut_substr(s, 0, s_len - 3);
+    CHECK_TRUE(out);
+    CHECK_STREQ(out, "ee.");
+    free(out);
+    // Cut inside string.
+    out = simple_archiver_helper_cut_substr(s, 4, 8);
+    CHECK_TRUE(out);
+    CHECK_STREQ(out, "one three.");
+    free(out);
+  }
+
   printf("Checks checked: %u\n", checks_checked);
   printf("Checks passed:  %u\n", checks_passed);
   return checks_passed == checks_checked ? 0 : 1;