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confluent/confluent_osdeploy/utils/urlmount3.c
Jarrod Johnson 08e19fbf6e Provide a sample for fuse3 urlmount
When the time comes to transition, this will be useful.

The challenge is that existing images will likely have a 'distribution'
with fuse2 libs, so this isn't a transition to make lightly.

Definitely should be done for new distributions at least, current
distributions pending further investigation
2023-04-04 10:39:12 -04:00

349 lines
11 KiB
C

/*
# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2021 Lenovo
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
*/
#define FUSE_USE_VERSION 30
#include <fuse3/fuse.h>
#include <curl/curl.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <pthread.h>
#include <unistd.h>
CURL *curl;
char curlerror[CURL_ERROR_SIZE];
curl_off_t filesize;
typedef struct downloadbuffer {
char *response;
size_t completed;
size_t total;
} downloadbuffer;
#define MAX_FILE_LEN 1024
#define MAX_URL_PATHS 512
static char filename[MAX_FILE_LEN + 1];
static int urlidx, newidx;
static char* urls[MAX_URL_PATHS + 1];
void *http_rechecker(void *argp) {
CURL *checkurl;
int tmpidx, tmpval;
tmpidx = open("/dev/urandom", O_RDONLY);
if (tmpidx <= 0 || read(tmpidx, (char*)&tmpval, 4) < 0)
tmpval = time(NULL) & 0xffffffff;
if (tmpidx >= 0)
close(tmpidx);
srand(tmpval);
checkurl = curl_easy_init();
if (curl_easy_setopt(checkurl, CURLOPT_ERRORBUFFER, curlerror) != CURLE_OK) {
fprintf(stderr, "Error buffer\n");
exit(1);
}
//We want to consider error conditions fatal, rather than
//passing error text as data
if (curl_easy_setopt(checkurl, CURLOPT_FAILONERROR, 1L) != CURLE_OK) {
fprintf(stderr, "Fail on error\n");
exit(1);
}
if (curl_easy_setopt(checkurl, CURLOPT_TIMEOUT, 10L) != CURLE_OK) {
fprintf(stderr, "Error setting timeout\n");
exit(1);
}
if (curl_easy_setopt(checkurl, CURLOPT_NOBODY, 1) != CURLE_OK) {
fprintf(stderr, "Error setting nobody\n");
exit(1);
}
while (1) {
sleep(25 + tmpval % 10); // Spread out retries across systems
tmpidx = 0;
while (tmpidx < urlidx && tmpidx < newidx && urls[tmpidx] != NULL) {
if (curl_easy_setopt(checkurl, CURLOPT_URL, urls[tmpidx]) != CURLE_OK) {
tmpidx++;
continue;
}
if (curl_easy_perform(checkurl) == CURLE_OK)
newidx = tmpidx;
else
tmpidx++;
}
}
}
static int http_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
off_t offset, struct fuse_file_info *fi, enum fuse_readdir_flags frf)
{
if (strcmp(path, "/") != 0) // We don't support subdirs
return -ENOENT;
filler(buf, ".", NULL, 0, 0);
filler(buf, "..", NULL, 0, 0);
filler(buf, filename + 1, NULL, 0, 0);
return 0;
}
size_t fill_buffer(char *data, size_t size, size_t nmemb, downloadbuffer *userdata) {
size_t amount;
amount = size * nmemb;
if (userdata->total < amount + userdata->completed) return 0;
memcpy(&(userdata->response[userdata->completed]), data, amount);
userdata->completed += amount;
return amount;
}
static int http_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi) {
char headbuffer[512];
double dldbl = 0.0;
int startidx;
int reconnecting = 0;
FILE* fd;
startidx = urlidx;
memset(buf, 0, size);
curl_off_t downloaded;
//Would be needed for multithread, however preferring to conserve
//filehandles rather than go multithread
// Some comparisons showed that the threaded performance boost doesn't
// do even offset the overhead of the new curl handles, so better
// to use single threaded curl overall for now
//CURL *tmpcurl = curl_easy_duphandle(curl);
downloadbuffer dlbuf;
dlbuf.response = buf;
dlbuf.completed = 0;
dlbuf.total = size;
fd = NULL;
if (strcmp(path, filename) != 0) return -ENOENT;
memset(headbuffer, 0, 512);
if (offset >= filesize) return 0;
if (offset + size - 1 >= filesize) size = filesize - offset - 1;
snprintf(headbuffer, 512, "%ld-%ld", offset, offset + size - 1);
if (curl_easy_setopt(curl, CURLOPT_RANGE, headbuffer) != CURLE_OK) {
fprintf(stderr, "Error setting range\n");
exit(1);
}
if (curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&dlbuf) != CURLE_OK) {
fprintf(stderr, "Error setting writedata\n");
exit(1);
}
if (newidx < MAX_URL_PATHS) {
reconnecting = 1;
urlidx = newidx;
newidx = MAX_URL_PATHS;
fd = fopen("/dev/kmsg", "w+");
fprintf(fd, "<5>urlmount: Connecting to %s\n", urls[urlidx]);
fclose(fd);
// if fail, carry on and take the error in curl_easy_perform instead
if (curl_easy_setopt(curl, CURLOPT_URL, urls[urlidx]) != CURLE_OK) {}
}
while (curl_easy_perform(curl) != CURLE_OK) {
reconnecting = 1;
fd = fopen("/dev/kmsg", "w+");
dlbuf.completed = 0;
fprintf(fd, "<4>urlmount: error while communicating with %s: %s\n", urls[urlidx], curlerror);
fclose(fd);
urlidx++;
if (urlidx > MAX_URL_PATHS)
urlidx = 0;
if (urls[urlidx] == NULL)
urlidx = 0;
if (urlidx == startidx) {
fd = fopen("/dev/kmsg", "w+");
fprintf(fd, "<1>urlmount: All connections to source are down\n");
fclose(fd);
sleep(10);
}
fd = fopen("/dev/kmsg", "w+");
fprintf(fd, "<5>urlmount: Connecting to %s\n", urls[urlidx]);
fclose(fd);
if (urlidx > MAX_URL_PATHS) {
fprintf(stderr, "Maximum url path exceeded\n");
exit(1);
}
// ignore, let the curl_easy_perform get the error
if (curl_easy_setopt(curl, CURLOPT_URL, urls[urlidx]) != CURLE_OK) {}
}
if (reconnecting) {
fd = fopen("/dev/kmsg", "w+");
fprintf(fd, "<5>urlmount: Successfully connected to %s\n", urls[urlidx]);
fclose(fd);
}
curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &dldbl);
downloaded = round(dldbl);
//Would be needed for multithread
//curl_easy_cleanup(tmpcurl);
return downloaded;
}
static int http_open(const char *path, struct fuse_file_info *fi) {
if (strcmp(path, filename) != 0)
return -ENOENT;
if ((fi->flags & 3) != O_RDONLY)
return -EACCES;
return 0;
}
static void* http_init(struct fuse_conn_info *conn, struct fuse_config *cfg) {
// Because we fork, we need to redo curl
// or else suffer the wrath of NSS TLS
pthread_t tid;
curl_global_init(CURL_GLOBAL_DEFAULT);
pthread_create(&tid, NULL, http_rechecker, NULL);
curl = curl_easy_init();
if (curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, curlerror) != CURLE_OK) {
fprintf(stderr, "Failure initializing libcurl error buffor\n");
exit(1);
}
//We want to consider error conditions fatal, rather than
//passing error text as data
if (curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L) != CURLE_OK) {
fprintf(stderr, "Failure initializing libcurl failonerror\n");
exit(1);
}
if (curl_easy_setopt(curl, CURLOPT_TIMEOUT, 10L) != CURLE_OK) {
fprintf(stderr, "Failure initializing libcurl timeout\n");
exit(1);
}
if (curl_easy_setopt(curl, CURLOPT_URL, urls[urlidx]) != CURLE_OK) {
fprintf(stderr, "Failure initializing url\n");
exit(1);
}
if (curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fill_buffer) != CURLE_OK) {
fprintf(stderr, "Failure initializing libcurl fill buffer\n");
exit(1);
}
return NULL;
}
static int http_getattr(const char *path, struct stat *st, struct fuse_file_info *ffi) {
memset(st, 0, sizeof(struct stat));
if (strcmp(path, "/") == 0) {
st->st_mode = S_IFDIR | 0555;
st->st_nlink = 2;
} else if (strcmp(path, filename) == 0) {
st->st_mode = S_IFREG | 0444;
st->st_nlink = 1;
st->st_size = filesize; // TODO: fix with curl HEAD
} else
return -ENOENT;
return 0;
}
static const struct fuse_operations http_ops = {
.getattr = http_getattr,
.readdir = http_readdir,
.read = http_read,
.open = http_open,
.init = http_init,
};
int main(int argc, char* argv[]) {
char *tmp;
double fsize;
unsigned int i;
int j;
j = 0;
memset(urls, 0, 32*sizeof(char*));
urlidx = 0;
newidx = MAX_URL_PATHS;
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if (curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, curlerror) != CURLE_OK) {
fprintf(stderr, "Unable to set error buffer\n");
exit(1);
}
//We want to consider error conditions fatal, rather than
//passing error text as data
if (curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L) != CURLE_OK) {
fprintf(stderr, "Unable to set fail on error\n");
exit(1);
}
if (curl_easy_setopt(curl, CURLOPT_TIMEOUT, 15L) != CURLE_OK) {
fprintf(stderr, "Unable to setup curl timeout\n");
exit(1);
}
memset(filename, 0, MAX_FILE_LEN);
for (i=0; i < argc; i++) {
if (strstr(argv[i], ":") > 0) {
if (j < MAX_URL_PATHS) {
urls[j] = argv[i];
tmp = strrchr(urls[j++], '/');
strncpy(filename, tmp, MAX_FILE_LEN);
}
//Request single threaded mode, as curl would need more
// filehandles for multithread
argv[i] = "-s";
}
}
if (filename[0] == 0) {
fprintf(stderr, "No URL given in arguments\n");
exit(1);
}
for (i=0; urls[i] != NULL; i++) {
printf("Registering mount path: %s\n", urls[i]);
}
j = urlidx;
printf("Connecting to %s\n", urls[urlidx]);
if (curl_easy_setopt(curl, CURLOPT_URL, urls[urlidx]) != CURLE_OK) {
fprintf(stderr, "Unable to set url\n");
}
if (curl_easy_setopt(curl, CURLOPT_NOBODY, 1) != CURLE_OK) {
fprintf(stderr, "Failure setting no body\n");
}
while (curl_easy_perform(curl) != CURLE_OK) {
fprintf(stderr, "urlmount: error while communicating with %s: %s\n", urls[urlidx++], curlerror);
if (urls[urlidx] == NULL)
urlidx = 0;
if (urlidx == j) {
fprintf(stderr, "urlmount: Unable to reach any target url, aborting\n");
exit(1);
}
printf("Connecting to %s\n", urls[urlidx]);
if (curl_easy_setopt(curl, CURLOPT_URL, urls[urlidx]) != CURLE_OK) {
fprintf(stderr, "Unable to set url\n");
}
}
printf("Successfully connected to %s\n", urls[urlidx]);
if (curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &fsize) != CURLE_OK) {
fprintf(stderr, "Failed getting content length\n");
exit(1);
}
filesize = round(fsize);
if (curl_easy_setopt(curl, CURLOPT_NOBODY, 0) != CURLE_OK) {
fprintf(stderr, "Failed setting nobody\n");
exit(1);
}
if (filesize < 1) {
fprintf(stderr, "Unable to reach designated URL\n");
exit(1);
}
if (!curl) {
fprintf(stderr, "Unable to initialize CURL!\n");
exit(1);
}
curl_easy_cleanup(curl);
curl_global_cleanup();
fuse_main(argc, argv, &http_ops, NULL);
}