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#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <errno.h>
#include <stdatomic.h>
#include <pthread.h>
#include <sys/stat.h>
#include "memory.h"
#include "util.h"
#include "mime.h"
#include "hashtable.h"
#include "buffer.h"
static char* process_read(const char *cmd, char **argv) {
const int error_exit_status = 97;
int outpipe[2];
if (pipe(outpipe) < 0) {
perror("pipe");
exit(1);
}
pid_t pid = fork();
if (pid < 0) {
perror("fork");
exit(1);
}
if (pid == 0) {
close(outpipe[0]);
dup2(outpipe[1], STDOUT_FILENO);
execvp(cmd, argv);
perror("execvp");
exit(error_exit_status);
}
close(outpipe[1]);
struct buffer buffer = buffer_make(256);
char tempbuf[256];
while (true) {
ssize_t nr = read(outpipe[0], tempbuf, sizeof tempbuf);
if (nr < 0) {
if (errno == EINTR) continue;
perror("read");
break;
}
if (nr == 0) break; // eof
buffer_append_mem(&buffer, tempbuf, nr);
}
close(outpipe[0]);
while (true) {
int status;
if (waitpid(pid, &status, 0) < 0) {
if (errno == EINTR) continue;
perror("waitpid");
return NULL;
}
if (WIFEXITED(status)) {
if (WEXITSTATUS(status) == error_exit_status) {
buffer_free(buffer);
return NULL;
} else if (WEXITSTATUS(status) == 0) {
return buffer.buf;
} else {
fprintf(stderr, "Command '%s' had unexpected exit code %d!\n", cmd, WEXITSTATUS(status));
return NULL;
}
}
}
}
static struct timespec get_file_mtime(const char *path) {
struct stat st;
memset(&st, 0, sizeof st);
if (stat(path, &st) < 0) {
return (struct timespec){.tv_sec = -1, .tv_nsec = -1};
}
#if defined(__LINUX__)
return st.st_mtim;
#elif defined(__APPLE__)
return st.st_mtimespec;
#else
#error Unknown operating system, how does the stat() data structure look?
#endif
}
static void strip_string(char *str) {
size_t len = strlen(str);
size_t idx = 0;
while (str[idx] && isspace(str[idx])) idx++;
if (idx > 0) memmove(str, str + idx, len - idx + 1);
len -= idx;
while (len > 0 && isspace(str[len - 1])) str[--len] = '\0';
}
struct cache_entry {
char *mimetype;
struct timespec mtime;
};
HASHTABLE_DEFINE(mht_, struct cache_entry)
struct mime_storage {
struct mht_table *mime_ht;
};
static struct mime_storage global_storage = {NULL};
static pthread_mutex_t global_storage_mutex;
static struct atomic_flag global_storage_inited = ATOMIC_FLAG_INIT;
// Cannot be atomic_flag's because we need to load them without changing them
static atomic_bool xdg_works = ATOMIC_VAR_INIT(true);
static atomic_bool file_works = ATOMIC_VAR_INIT(true);
#define WITH_MIME_STORAGE_LOCK(...) \
do { \
PTHREAD_CHECK(pthread_mutex_lock, &global_storage_mutex); \
{__VA_ARGS__}; \
PTHREAD_CHECK(pthread_mutex_unlock, &global_storage_mutex); \
} while (0)
void mime_init(void) {
if (!atomic_flag_test_and_set(&global_storage_inited)) {
PTHREAD_CHECK(pthread_mutex_init, &global_storage_mutex, NULL);
global_storage.mime_ht = malloc(1, struct mht_table);
*global_storage.mime_ht = mht_make();
}
}
static char* mime_detect_xdg(const char *path) {
char *pathdup = strdup(path);
char *argv[5] = { "xdg-mime", "query", "filetype", pathdup, NULL };
char *output = process_read("xdg-mime", argv);
free(pathdup);
if (output) strip_string(output);
return output;
}
static char* mime_detect_file(const char *path) {
char *pathdup = strdup(path);
char *argv[6] = { "file", "--brief", "--dereference", "--mime-type", pathdup, NULL };
char *output = process_read("file", argv);
free(pathdup);
if (output) strip_string(output);
return output;
}
static char* mime_detect_perform(const char *path) {
// Try 'file' first, because xdg-mime calls that on my system
if (atomic_load(&file_works)) {
fprintf(stderr, "mime: trying 'file'...\n");
char *typ = mime_detect_file(path);
if (typ) return typ;
atomic_store(&file_works, false);
fprintf(stderr, "mime: 'file' doesn't work\n");
}
if (atomic_load(&xdg_works)) {
fprintf(stderr, "mime: trying 'xdg'...\n");
char *typ = mime_detect_xdg(path);
if (typ) return typ;
atomic_store(&xdg_works, false);
fprintf(stderr, "mime: 'xdg-mime' doesn't work\n");
}
fprintf(stderr, "No working mimetype detection! Please fix " __FILE__ " for this platform!\n");
return NULL;
}
const char* mime_detect(const char *path) {
struct timespec now_mtime = get_file_mtime(path);
if (now_mtime.tv_sec < 0) return NULL;
char *typ = NULL;
WITH_MIME_STORAGE_LOCK(
struct cache_entry *entry = mht_find(global_storage.mime_ht, path);
if (entry) {
if (now_mtime.tv_sec > entry->mtime.tv_sec ||
(now_mtime.tv_sec == entry->mtime.tv_sec &&
now_mtime.tv_nsec > entry->mtime.tv_nsec)) {
fprintf(stderr, "Erasing <%s>\n", path);
mht_erase(global_storage.mime_ht, path);
} else {
typ = entry->mimetype;
}
}
);
if (typ) return typ;
typ = mime_detect_perform(path);
if (typ) {
struct cache_entry entry;
entry.mimetype = typ;
entry.mtime = now_mtime;
WITH_MIME_STORAGE_LOCK(
fprintf(stderr, "Inserting <%s> -> <%s>\n", path, typ);
mht_insert(global_storage.mime_ht, path, entry);
);
}
return typ;
}
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