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sesimos/src/lib/cache.c

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/**
* Necronda Web Server
* File cache implementation
* src/lib/cache.c
* Lorenz Stechauner, 2020-12-19
*/
#include "cache.h"
#include "utils.h"
#include "compress.h"
#include <stdio.h>
#include <magic.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <openssl/sha.h>
#include <malloc.h>
int cache_continue = 1;
magic_t magic;
cache_entry *cache;
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, CACHE_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(CACHE_SHM_KEY, CACHE_ENTRIES * sizeof(cache_entry), 0);
if (shm_id < 0) {
fprintf(stderr, ERR_STR "Unable to create cache 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 cache shared memory (rw): %s" CLR_STR "\n", strerror(errno));
return -2;
}
cache = shm_rw;
if (mkdir("/var/necronda/", 0755) < 0 && errno != EEXIST) {
fprintf(stderr, ERR_STR "Unable to create directory '/var/necronda/': %s" CLR_STR "\n", strerror(errno));
return -3;
}
if (mkdir("/var/necronda/server/", 0755) < 0 && errno != EEXIST) {
fprintf(stderr, ERR_STR "Unable to create directory '/var/necronda/server/': %s" CLR_STR "\n", strerror(errno));
return -3;
}
FILE *cache_file = fopen("/var/necronda/server/cache", "rb");
if (cache_file != NULL) {
fread(cache, sizeof(cache_entry), CACHE_ENTRIES, cache_file);
fclose(cache_file);
}
for (int i = 0; i < CACHE_ENTRIES; i++) {
cache[i].is_updating = 0;
}
FILE *file;
char *buf = malloc(CACHE_BUF_SIZE);
char *comp_buf = malloc(CACHE_BUF_SIZE);
char filename_comp_gz[256];
char filename_comp_br[256];
unsigned long read;
int compress;
SHA_CTX ctx;
unsigned char hash[SHA_DIGEST_LENGTH];
int cache_changed = 0;
int p_len_gz, p_len_br;
int ret;
while (cache_continue) {
for (int i = 0; i < CACHE_ENTRIES; i++) {
if (cache[i].filename[0] != 0 && cache[i].meta.etag[0] == 0 && !cache[i].is_updating) {
cache[i].is_updating = 1;
fprintf(stdout, "[cache] Hashing file %s\n", cache[i].filename);
SHA1_Init(&ctx);
file = fopen(cache[i].filename, "rb");
compress = mime_is_compressible(cache[i].meta.type);
compress_ctx comp_ctx;
FILE *comp_file_gz = NULL;
FILE *comp_file_br = NULL;
if (compress) {
sprintf(buf, "%.*s/.necronda-server", cache[i].webroot_len, cache[i].filename);
if (mkdir(buf, 0755) != 0 && errno != EEXIST) {
fprintf(stderr, ERR_STR "Unable to create directory %s: %s" CLR_STR "\n", buf, strerror(errno));
goto comp_err;
}
sprintf(buf, "%.*s/.necronda-server/cache", cache[i].webroot_len, cache[i].filename);
if (mkdir(buf, 0700) != 0 && errno != EEXIST) {
fprintf(stderr, ERR_STR "Unable to create directory %s: %s" CLR_STR "\n", buf, strerror(errno));
goto comp_err;
}
char *rel_path = cache[i].filename + cache[i].webroot_len + 1;
for (int j = 0; j < strlen(rel_path); j++) {
char ch = rel_path[j];
if (ch == '/') ch = '_';
buf[j] = ch;
}
buf[strlen(rel_path)] = 0;
p_len_gz = snprintf(filename_comp_gz, sizeof(filename_comp_gz),
"%.*s/.necronda-server/cache/%s.gz",
cache[i].webroot_len, cache[i].filename, buf);
p_len_br = snprintf(filename_comp_br, sizeof(filename_comp_br),
"%.*s/.necronda-server/cache/%s.br",
cache[i].webroot_len, cache[i].filename, buf);
if (p_len_gz < 0 || p_len_gz >= sizeof(filename_comp_gz) ||
p_len_br < 0 || p_len_br >= sizeof(filename_comp_br))
{
fprintf(stderr, ERR_STR "Unable to open cached file: "
"File name for compressed file too long" CLR_STR "\n");
goto comp_err;
}
fprintf(stdout, "[cache] Compressing file %s\n", cache[i].filename);
comp_file_gz = fopen(filename_comp_gz, "wb");
comp_file_br = fopen(filename_comp_br, "wb");
if (comp_file_gz == NULL || comp_file_br == NULL) {
fprintf(stderr, ERR_STR "Unable to open cached file: %s" CLR_STR "\n", strerror(errno));
comp_err:
compress = 0;
} else {
ret = compress_init(&comp_ctx, COMPRESS_GZ | COMPRESS_BR);
if (ret != 0) {
fprintf(stderr, ERR_STR "Unable to init compression: %s" CLR_STR "\n", strerror(errno));
compress = 0;
fclose(comp_file_gz);
fclose(comp_file_br);
}
}
}
while ((read = fread(buf, 1, CACHE_BUF_SIZE, file)) > 0) {
SHA1_Update(&ctx, buf, read);
if (compress) {
unsigned long avail_in, avail_out;
avail_in = read;
do {
avail_out = CACHE_BUF_SIZE;
compress_compress_mode(&comp_ctx, COMPRESS_GZ,buf + read - avail_in, &avail_in,
comp_buf, &avail_out, feof(file));
fwrite(comp_buf, 1, CACHE_BUF_SIZE - avail_out, comp_file_gz);
} while (avail_in != 0 || avail_out != CACHE_BUF_SIZE);
avail_in = read;
do {
avail_out = CACHE_BUF_SIZE;
compress_compress_mode(&comp_ctx, COMPRESS_BR, buf + read - avail_in, &avail_in,
comp_buf, &avail_out, feof(file));
fwrite(comp_buf, 1, CACHE_BUF_SIZE - avail_out, comp_file_br);
} while (avail_in != 0 || avail_out != CACHE_BUF_SIZE);
}
}
if (compress) {
compress_free(&comp_ctx);
fclose(comp_file_gz);
fclose(comp_file_br);
fprintf(stdout, "[cache] Finished compressing file %s\n", cache[i].filename);
strcpy(cache[i].meta.filename_comp_gz, filename_comp_gz);
strcpy(cache[i].meta.filename_comp_br, filename_comp_br);
} else {
memset(cache[i].meta.filename_comp_gz, 0, sizeof(cache[i].meta.filename_comp_gz));
memset(cache[i].meta.filename_comp_br, 0, sizeof(cache[i].meta.filename_comp_br));
}
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);
fprintf(stdout, "[cache] Finished hashing file %s\n", cache[i].filename);
cache[i].is_updating = 0;
cache_changed = 1;
}
}
if (cache_changed) {
cache_changed = 0;
cache_file = fopen("/var/necronda/server/cache", "wb");
if (cache_file == NULL) {
fprintf(stderr, ERR_STR "Unable to open cache file: %s" CLR_STR "\n", strerror(errno));
free(buf);
free(comp_buf);
return -1;
}
fwrite(cache, sizeof(cache_entry), CACHE_ENTRIES, cache_file);
fclose(cache_file);
} else {
sleep(1);
}
}
free(buf);
free(comp_buf);
return 0;
}
int cache_init() {
if (magic_init() != 0) {
return -1;
}
int shm_id = shmget(CACHE_SHM_KEY, CACHE_ENTRIES * sizeof(cache_entry), IPC_CREAT | IPC_EXCL | 0600);
if (shm_id < 0) {
fprintf(stderr, ERR_STR "Unable to create cache 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 cache 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 cache shared memory (rw): %s" CLR_STR "\n", strerror(errno));
return -4;
}
cache = shm_rw;
memset(cache, 0, CACHE_ENTRIES * sizeof(cache_entry));
shmdt(shm_rw);
cache = shm;
pid_t pid = fork();
if (pid == 0) {
// child
if (cache_process() == 0) {
return 0;
} else {
return -6;
}
} else if (pid > 0) {
// parent
fprintf(stderr, "Started child process with PID %i as cache-updater\n", pid);
return pid;
} else {
fprintf(stderr, ERR_STR "Unable to create child process: %s" CLR_STR "\n", strerror(errno));
return -5;
}
}
int cache_unload() {
int shm_id = shmget(CACHE_SHM_KEY, 0, 0);
if (shm_id < 0) {
fprintf(stderr, ERR_STR "Unable to get cache shared memory id: %s" CLR_STR "\n", strerror(errno));
shmdt(cache);
return -1;
} else if (shmctl(shm_id, IPC_RMID, NULL) < 0) {
fprintf(stderr, ERR_STR "Unable to configure cache shared memory: %s" CLR_STR "\n", strerror(errno));
shmdt(cache);
return -1;
}
shmdt(cache);
return 0;
}
int cache_update_entry(int entry_num, const char *filename, const char *webroot) {
void *cache_ro = cache;
int shm_id = shmget(CACHE_SHM_KEY, 0, 0);
void *shm_rw = shmat(shm_id, NULL, 0);
if (shm_rw == (void *) -1) {
print(ERR_STR "Unable to attach cache 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));
cache[entry_num].webroot_len = (unsigned char) strlen(webroot);
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/", 5) == 0) {
if (strcmp(filename + strlen(filename) - 4, ".css") == 0) {
sprintf(type_new, "text/css");
} else if (strcmp(filename + strlen(filename) - 3, ".js") == 0) {
sprintf(type_new, "application/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));
memset(cache[entry_num].meta.filename_comp_gz, 0, sizeof(cache[entry_num].meta.filename_comp_gz));
memset(cache[entry_num].meta.filename_comp_br, 0, sizeof(cache[entry_num].meta.filename_comp_br));
cache[entry_num].is_updating = 0;
shmdt(shm_rw);
cache = cache_ro;
return 0;
}
int cache_filename_comp_invalid(const char *filename) {
void *cache_ro = cache;
int shm_id = shmget(CACHE_SHM_KEY, 0, 0);
void *shm_rw = shmat(shm_id, NULL, 0);
if (shm_rw == (void *) -1) {
print(ERR_STR "Unable to attach cache shared memory (rw): %s" CLR_STR, strerror(errno));
return -1;
}
cache = shm_rw;
int i;
for (i = 0; i < CACHE_ENTRIES; i++) {
if (cache[i].filename[0] != 0 && strlen(cache[i].filename) == strlen(filename) &&
strcmp(cache[i].filename, filename) == 0) {
if (cache[i].is_updating) {
return 0;
} else {
break;
}
}
}
memset(cache[i].meta.etag, 0, sizeof(cache[i].meta.etag));
memset(cache[i].meta.filename_comp_gz, 0, sizeof(cache[i].meta.filename_comp_gz));
memset(cache[i].meta.filename_comp_br, 0, sizeof(cache[i].meta.filename_comp_br));
cache[i].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 < CACHE_ENTRIES; 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 < CACHE_ENTRIES; i++) {
if (cache[i].filename[0] == 0) {
if (cache_update_entry(i, uri->filename, uri->webroot) != 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, uri->webroot) != 0) {
return -1;
}
}
}
return 0;
}
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