Add exec_tracker.c
This commit is contained in:
olemorud
394
exec_tracker.c
Normal file
394
exec_tracker.c
Normal file
@@ -0,0 +1,394 @@
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#include <assert.h>
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#include <dirent.h>
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#include <err.h>
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#include <errno.h>
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#include <poll.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/inotify.h>
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#include <sys/types.h>
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#include <unistd.h>
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#define BUFFER_LEN 4096
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static void handle_event(int inotify_instance, int *watched, char **filenames, int *counter, size_t watched_len);
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static char** filenames_in_dir(char *path, size_t *return_len);
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static char** filenames_in_path_envvar(size_t *return_len);
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static void free_null_terminated_pointer_array(char **ptr);
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static void print_event(uint32_t event);
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static void save_result(char **filenames, int* counter, size_t arr_len);
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/* This code is a bit over-commented in general */
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int
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main(int argc, char * const argv[])
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{
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/* Get null terminated list of files to watch, create counter of same size */
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char **file_names;
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int *use_counter, *watched;
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size_t files_len;
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switch (argc) {
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case 1:
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file_names = filenames_in_path_envvar(&files_len);
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break;
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case 2:
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file_names = filenames_in_dir(argv[1], &files_len);
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break;
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default:
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errx(EXIT_FAILURE, "Usage: `%s <dir>`. If dir is empty, directories in PATH will be monitored", argv[0]);
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}
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if (file_names == NULL)
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err(EXIT_FAILURE, "Error when finding files");
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use_counter = calloc(files_len, sizeof(int));
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if( use_counter == NULL )
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err(EXIT_FAILURE, "Failed to allocate %zu bytes for use counter", files_len*sizeof(int));
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/* Create file descriptor for accessing the inotify API */
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int inotify_instance = inotify_init();
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if ( inotify_instance == -1 )
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err(EXIT_FAILURE, "Failed to initialize inotify instance");
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/* Mark files for events */
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watched = calloc(files_len, sizeof(int));
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if( watched == NULL )
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err(EXIT_FAILURE, "Failed to allocate %zu bytes for watch descriptors", files_len*sizeof(int));
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for(size_t i=0; file_names[i] != NULL; i++) {
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watched[i] = inotify_add_watch(inotify_instance, file_names[i], IN_ACCESS);
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if(watched[i] == -1)
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err(EXIT_FAILURE, "Cannot watch %s", file_names[i]);
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}
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/* Prepare for polling */
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struct pollfd poll_fds[2];
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nfds_t fd_count = 2;
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poll_fds[0].fd = STDIN_FILENO;
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poll_fds[0].events = POLLIN;
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poll_fds[1].fd = inotify_instance;
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poll_fds[1].events = POLLIN;
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/* Wait for events and/or terminal input */
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int poll_num;
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fprintf(stderr, "Listening for events... (Press enter to end)\n");
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while (1) {
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poll_num = poll(poll_fds, fd_count, -1);
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if( poll_num == -1 && errno != EINTR)
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err(EXIT_FAILURE, "Failed to poll");
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if (poll_num == 0)
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continue;
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if (poll_fds[0].revents & POLLIN) {
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char c;
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while (read(STDIN_FILENO, &c, 1) > 0 && c != '\n')
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/* noop */;
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save_result(file_names, use_counter, files_len);
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break;
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}
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if( poll_fds[1].revents & POLLIN ) {
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handle_event(inotify_instance, watched, file_names, use_counter, files_len);
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}
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}
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close(inotify_instance);
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free_null_terminated_pointer_array(file_names);
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free(watched);
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free(use_counter);
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return EXIT_SUCCESS;
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}
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/* Free allocated memory pointed to by pointers
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in 'ptr', then free 'ptr' itself */
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static void
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free_null_terminated_pointer_array(char **ptr)
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{
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for(char **p = ptr; *p != NULL; p++ ){
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free(*p);
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}
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free(ptr);
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}
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/* Returns a null terminated array of strings
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for every file in PATH */
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static char**
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filenames_in_path_envvar(size_t *return_len) {
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size_t n_files, i, output_size;
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char **filenames, **output, *saveptr, *path, *token;
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void *tmp;
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path = strdup(getenv("PATH"));
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saveptr = NULL;
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output_size = 1024;
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output = malloc(output_size * sizeof(char*));
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if (output == NULL) {
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warn("Failed to allocate %zu bytes", output_size);
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return NULL;
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}
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token = strtok_r(path, ":", &saveptr);
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i = 0;
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while (token != NULL) {
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n_files = 0;
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filenames = filenames_in_dir(token, &n_files);
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n_files -= 1;
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if ( filenames == NULL ) {
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fprintf(stderr, "failed to get filenames in %s\n", token);
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token = strtok_r(NULL, ":", &saveptr);
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continue;
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}
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if (i + n_files > output_size) {
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while(i + n_files > output_size)
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output_size *= 2;
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tmp = realloc(output, output_size * sizeof(char*));
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if (tmp == NULL) {
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warn("failed to reallocate %zu bytes", output_size * sizeof(char*));
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return NULL;
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}
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output = (char**) tmp;
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}
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memcpy(output+i, filenames, n_files * sizeof(char*));
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i += n_files;
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free(filenames);
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token = strtok_r(NULL, ":", &saveptr);
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}
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output_size = i + 1;
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tmp = realloc(output, output_size * sizeof(char*));
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if (tmp != NULL){
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output = (char**)tmp;
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}
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output[i] = NULL;
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free(path);
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*return_len = output_size;
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return output;
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}
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/* Returns null terminated array
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of filepaths in directory */
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static char**
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filenames_in_dir(char *path, size_t *return_len)
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{
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size_t result_size, n_items=0;
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char **result;
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void *tmp;
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struct dirent *dir_entity;
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DIR *directory_stream;
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result_size = 64;
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result = malloc(result_size * sizeof(char*));
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if( result == NULL ){
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warn("Failed to malloc %zu bytes", result_size);
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return NULL;
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}
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directory_stream = opendir(path);
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if (directory_stream == NULL) {
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warn("Failed to open directory %s", path);
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goto fail;
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}
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n_items = 0;
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errno = 0; // To distinguish end of stream from an error,
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// set errno to zero before calling readdir()
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while ((dir_entity = readdir(directory_stream)) != NULL) {
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if(n_items >= result_size){
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result_size *= 2;
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result = realloc(result, result_size * sizeof(char*));
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}
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if (dir_entity->d_type == DT_REG ) {
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result[n_items] = calloc(strlen(path) + strlen(dir_entity->d_name) + 2, sizeof(char));
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result[n_items] = strcat(result[n_items], path);
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result[n_items] = strcat(result[n_items], "/");
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result[n_items] = strcat(result[n_items], dir_entity->d_name);
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n_items += 1;
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}
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// dirent *dir_entity is statically allocated, dont free()!
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}
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result_size = n_items+1;
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tmp = realloc(result, result_size * sizeof(char*));
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if ( tmp == NULL ) {
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warn("Failed to realloc %zu bytes", result_size);
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return NULL;
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}
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result = (char**)tmp;
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result[n_items] = NULL;
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if ( errno != 0 ){
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warn("Error when reading directory %s", path);
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goto fail;
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}
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if ( closedir(directory_stream) == -1 )
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warn("Failed to close directory");
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*return_len = result_size;
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return result;
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fail:
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for(size_t i=0; i<n_items; i++){
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free(result[i]);
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}
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free(result);
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if ( closedir(directory_stream) == -1 )
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warn("Failed to close directory");
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*return_len = 0;
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return NULL;
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}
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/* Read all available inotify events from
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file descriptor 'inotify_instance' */
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static void
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handle_event(int inotify_instance, int *watched, char **filenames, int *counter, size_t watched_len)
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{
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ssize_t length;
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const struct inotify_event *event;
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char buffer[BUFFER_LEN]
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__attribute__ ((aligned(__alignof__(struct inotify_event))));
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length = read(inotify_instance, buffer, BUFFER_LEN);
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if( length == -1 && errno != EAGAIN) {
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warn("Failed to read inotify event");
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return;
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}
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if (length == 0){
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return;
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}
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for (char *p = buffer; p < buffer+length; p += sizeof(struct inotify_event) + event->len) {
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event = (struct inotify_event *) p;
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for (int i=0; i < watched_len; i++) {
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if( watched[i] == event->wd ) {
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fprintf(stderr, "%s ", filenames[i]);
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counter[i] += 1;
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break;
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}
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}
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}
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}
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/* Prints event mask values in a human-readable format */
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static void
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print_event(uint32_t event)
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{
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if(event & IN_ACCESS){
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fprintf(stderr,"IN_ACCESS ");
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}
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if(event & IN_ATTRIB){
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fprintf(stderr,"IN_ATTRIB ");
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}
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if(event & IN_CLOSE_WRITE){
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fprintf(stderr,"IN_CLOSE_WRITE ");
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}
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if(event & IN_CLOSE_NOWRITE){
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fprintf(stderr,"IN_CLOSE_NOWRITE ");
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}
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if(event & IN_CREATE){
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fprintf(stderr,"IN_CREATE ");
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}
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if(event & IN_DELETE){
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fprintf(stderr,"IN_DELETE ");
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}
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if(event & IN_DELETE_SELF){
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fprintf(stderr,"IN_DELETE_SELF ");
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}
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if(event & IN_MODIFY){
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fprintf(stderr,"IN_MODIFY ");
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}
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if(event & IN_MOVE_SELF){
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fprintf(stderr,"IN_MOVE_SELF ");
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}
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if(event & IN_MOVED_FROM){
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fprintf(stderr,"IN_MOVED_FROM ");
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}
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if(event & IN_OPEN){
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fprintf(stderr,"IN_OPEN ");
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}
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}
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/* Saves number of recorded events for each
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executable t 'uses.log' */
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static void
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save_result(char **filenames, int* counter, size_t arr_len)
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{
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FILE *savefile;
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savefile = fopen("uses.log", "w");
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if (savefile == NULL) {
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warn("Failed to save to file");
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return;
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}
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for (size_t i=0; i<arr_len; i++) {
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if (counter[i] == 0)
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continue;
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fprintf(stdout, "%d %s\n", counter[i], filenames[i]);
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}
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fclose(savefile);
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}
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