Files
sesimos/src/cache.c
2020-12-23 18:21:03 +01:00

230 lines
6.9 KiB
C

/**
* Necronda Web Server
* File cache implementation
* src/cache.c
* Lorenz Stechauner, 2020-12-19
*/
#include "cache.h"
#include "uri.h"
int magic_init() {
magic = magic_open(MAGIC_MIME);
if (magic == NULL) {
fprintf(stderr, ERR_STR "Unable to open magic cookie: %s" CLR_STR "\n", strerror(errno));
return -1;
}
if (magic_load(magic, MAGIC_FILE) != 0) {
fprintf(stderr, ERR_STR "Unable to load magic cookie: %s" CLR_STR "\n", magic_error(magic));
return -2;
}
return 0;
}
void cache_process_term() {
cache_continue = 0;
}
int cache_process() {
signal(SIGINT, cache_process_term);
signal(SIGTERM, cache_process_term);
int shm_id = shmget(SHM_KEY, FILE_CACHE_SIZE * sizeof(cache_entry), 0);
if (shm_id < 0) {
fprintf(stderr, ERR_STR "Unable to create shared memory: %s" CLR_STR "\n", strerror(errno));
return -1;
}
shmdt(cache);
void *shm_rw = shmat(shm_id, NULL, 0);
if (shm_rw == (void *) -1) {
fprintf(stderr, ERR_STR "Unable to attach shared memory (rw): %s" CLR_STR "\n", strerror(errno));
return -2;
}
cache = shm_rw;
mkdir("/var/necronda-server", 0655);
FILE *cache_file = fopen("/var/necronda-server/cache", "rb");
if (cache_file != NULL) {
fread(cache, sizeof(cache_entry), FILE_CACHE_SIZE, cache_file);
fclose(cache_file);
}
for (int i = 0; i < FILE_CACHE_SIZE; i++) {
cache[i].is_updating = 0;
}
FILE *file;
char buf[16384];
unsigned long read;
int compress;
SHA_CTX ctx;
unsigned char hash[SHA_DIGEST_LENGTH];
while (cache_continue) {
for (int i = 0; i < FILE_CACHE_SIZE; i++) {
if (cache[i].filename[0] != 0 && cache[i].meta.etag[0] == 0 && !cache[i].is_updating) {
cache[i].is_updating = 1;
SHA1_Init(&ctx);
file = fopen(cache[i].filename, "rb");
compress = strncmp(cache[i].meta.type, "text/", 5) == 0;
while ((read = fread(buf, 1, sizeof(buf), file)) > 0) {
SHA1_Update(&ctx, buf, read);
if (compress) {
// TODO compress text/* files
}
}
SHA1_Final(hash, &ctx);
memset(cache[i].meta.etag, 0, sizeof(cache[i].meta.etag));
for (int j = 0; j < SHA_DIGEST_LENGTH; j++) {
sprintf(cache[i].meta.etag + j * 2, "%02x", hash[j]);
}
fclose(file);
cache[i].is_updating = 0;
}
}
cache_file = fopen("/var/necronda-server/cache", "wb");
fwrite(cache, sizeof(cache_entry), FILE_CACHE_SIZE , cache_file);
fclose(cache_file);
sleep(1);
}
return 0;
}
int cache_init() {
if (magic_init() != 0) {
return -1;
}
int shm_id = shmget(SHM_KEY, FILE_CACHE_SIZE * sizeof(cache_entry), IPC_CREAT | IPC_EXCL);
if (shm_id < 0) {
fprintf(stderr, ERR_STR "Unable to create shared memory: %s" CLR_STR "\n", strerror(errno));
return -2;
}
void *shm = shmat(shm_id, NULL, SHM_RDONLY);
if (shm == (void *) -1) {
fprintf(stderr, ERR_STR "Unable to attach shared memory (ro): %s" CLR_STR "\n", strerror(errno));
return -3;
}
cache = shm;
void *shm_rw = shmat(shm_id, NULL, 0);
if (shm_rw == (void *) -1) {
fprintf(stderr, ERR_STR "Unable to attach shared memory (rw): %s" CLR_STR "\n", strerror(errno));
return -4;
}
cache = shm_rw;
memset(cache, 0, FILE_CACHE_SIZE * sizeof(cache_entry));
shmdt(shm_rw);
cache = shm;
pid_t pid = fork();
if (pid == 0) {
// child
if (cache_process() == 0) {
return 1;
} else {
return -6;
}
} else if (pid > 0) {
// parent
fprintf(stderr, "Started child process with PID %i as cache-updater\n", pid);
children[0] = pid;
} else {
fprintf(stderr, ERR_STR "Unable to create child process: %s" CLR_STR "\n", strerror(errno));
return -5;
}
return 0;
}
int cache_unload() {
int shm_id = shmget(SHM_KEY, 0, 0);
if (shm_id < 0) {
fprintf(stderr, ERR_STR "Unable to create shared memory: %s" CLR_STR "\n", strerror(errno));
} else if (shmctl(shm_id, IPC_RMID, NULL) < 0) {
fprintf(stderr, ERR_STR "Unable to configure shared memory: %s" CLR_STR "\n", strerror(errno));
}
shmdt(cache);
return 0;
}
int cache_update_entry(int entry_num, const char *filename) {
void *cache_ro = cache;
int shm_id = shmget(SHM_KEY, 0, 0);
void *shm_rw = shmat(shm_id, NULL, 0);
if (shm_rw == (void *) -1) {
print(ERR_STR "Unable to attach shared memory (rw): %s" CLR_STR, strerror(errno));
return -1;
}
cache = shm_rw;
struct stat statbuf;
stat(filename, &statbuf);
memcpy(&cache[entry_num].meta.stat, &statbuf, sizeof(statbuf));
strcpy(cache[entry_num].filename, filename);
magic_setflags(magic, MAGIC_MIME_TYPE);
const char *type = magic_file(magic, filename);
char type_new[24];
sprintf(type_new, "%s", type);
if (strncmp(type, "text/plain", 10) == 0) {
if (strncmp(filename + strlen(filename) - 4, ".css", 4) == 0) {
sprintf(type_new, "text/css");
} else if (strncmp(filename + strlen(filename) - 3, ".js", 3) == 0) {
sprintf(type_new, "text/javascript");
}
}
strcpy(cache[entry_num].meta.type, type_new);
magic_setflags(magic, MAGIC_MIME_ENCODING);
strcpy(cache[entry_num].meta.charset, magic_file(magic, filename));
memset(cache[entry_num].meta.etag, 0, sizeof(cache[entry_num].meta.etag));
cache[entry_num].is_updating = 0;
shmdt(shm_rw);
cache = cache_ro;
return 0;
}
int uri_cache_init(http_uri *uri) {
if (uri->filename == NULL) {
return 0;
}
int i;
for (i = 0; i < FILE_CACHE_SIZE; i++) {
if (cache[i].filename[0] != 0 && strlen(cache[i].filename) == strlen(uri->filename) &&
strcmp(cache[i].filename, uri->filename) == 0) {
uri->meta = &cache[i].meta;
if (cache[i].is_updating) {
return 0;
} else {
break;
}
}
}
if (uri->meta == NULL) {
for (i = 0; i < FILE_CACHE_SIZE; i++) {
if (cache[i].filename[0] == 0) {
if (cache_update_entry(i, uri->filename) != 0) {
return -1;
}
uri->meta = &cache[i].meta;
break;
}
}
} else {
struct stat statbuf;
stat(uri->filename, &statbuf);
if (memcmp(&uri->meta->stat.st_mtime, &statbuf.st_mtime, sizeof(statbuf.st_mtime)) != 0) {
if (cache_update_entry(i, uri->filename) != 0) {
return -1;
}
}
}
return 0;
}