Instead of using syscall try reading /etc/mtab to figure out director… (#615)

#612 : Instead of using syscall try reading /etc/mtab to figure out directory is already mounted or not. Use cli option "--basic-remount-check=true" to enable this.
#613 : Skip cURL check and validate authentication before the mount to return early failure for invalid authentication. Use cli option "--pre-mount-validate=true" to enable this.

README.md

@@ -74,6 +74,8 @@ For more information, see the [wiki](https://github.com/Azure/azure-storage-fuse
      * [OPTIONAL] **--httpproxy=http://10.1.22.4:8080/** : Only used when https is turned off using --use-https=false, and if external network is only available through a proxy server, this parameter should specify the proxy server along with the port which is 8080 unless there are some deviations from normal port allocation numbers. This option is only available from version 1.3.7
      * [OPTIONAL] **--max-retry=26** : Maximum retry count if the failure codes are retryable. Default count is 26.
      * [OPTIONAL] **--max-retry-interval-in-seconds=60** : Maximum number of seconds between 2 retries, retry interval is exponentially increased but it can never exceed this value. Default naximum interval is 60 seconds.
+     * [OPTIONAL] **--basic-remount-check=false** : Try checking for a remount by reading /etc/mtab instead of calling the syscall setmntent
+     * [OPTIONAL] **--pre-mount-validate=false** : Skip cURL version check and validate storage connection before mount.
 
 ### Valid authentication setups:
 

blobfuse-artifacts.yml

@@ -362,15 +362,15 @@ stages:
           displayName: "Print Agent Info"
 
         # Install all dependencies
-        - script: |
-            #sudo zypper in <>
-            sudo zypper -n update git tar make cmake gcc gcc-c++ curl-devel gnutls-devel libuuid-devel boost-devel libboost*devel libgcrypt-devel rpm-build
-          displayName: "Basic Tools Setup"
+        #- script: |
+        #    #sudo zypper in <>
+        #    sudo zypper -n update git tar make cmake gcc gcc-c++ curl-devel gnutls-devel libuuid-devel boost-devel libboost*devel libgcrypt-devel rpm-build
+        #  displayName: "Basic Tools Setup"
 
         # Install libfuse
-        - script: |
-            sudo zypper -n update fuse-devel
-          displayName: "libFuse Setup"
+        #- script: |
+        #    sudo zypper -n update fuse-devel
+        #  displayName: "libFuse Setup"
 
         # Prebuild cleanup
         - script: |

blobfuse-nightly.yml

@@ -1252,14 +1252,14 @@ jobs:
           displayName: "Print Agent Info"
 
         # Install all dependencies
-        - script: |
-            sudo zypper -n update git tar make cmake gcc gcc-c++ curl-devel gnutls-devel libuuid-devel boost-devel libboost*devel libgcrypt-devel rpm-build go
-          displayName: "Basic Tools Setup"
+        #- script: |
+        #    sudo zypper -n update git tar make cmake gcc gcc-c++ curl-devel gnutls-devel libuuid-devel boost-devel libboost*devel libgcrypt-devel rpm-build go
+        #  displayName: "Basic Tools Setup"
 
         # Install libfuse
-        - script: |
-            sudo zypper -n update fuse-devel fuse
-          displayName: "libFuse Setup"
+        #- script: |
+        #    sudo zypper -n update fuse-devel fuse
+        #  displayName: "libFuse Setup"
 
         # Prebuild cleanup
         - script: |

blobfuse/blobfuse.cpp

@@ -61,11 +61,12 @@ const struct fuse_opt option_spec[] =
     OPTION("--ca-cert-file=%s", caCertFile),
     OPTION("--https-proxy=%s", httpsProxy),
     OPTION("--http-proxy=%s", httpProxy),
-
     OPTION("--max-retry=%s", max_retry),
     OPTION("--max-retry-interval-in-seconds=%s", max_timeout),
     OPTION("--retry-delay-factor=%s", retry_delay),
-
+    OPTION("--basic-remount-check=%s", basic_remount_check),
+    OPTION("--pre-mount-validate=%s", pre_mount_validate),
+    
     OPTION("--version", version),
     OPTION("-v", version),
     OPTION("--help", help),
@@ -417,7 +418,7 @@ void *azs_init(struct fuse_conn_info * conn)
     g_gc_cache = std::make_shared<gc_cache>(config_options.tmpPath, config_options.fileCacheTimeoutInSeconds);
     g_gc_cache->run();
     
-    if (libcurl_version < blobfuse_constants::minCurlVersion) {
+    if (!config_options.preMountValidate && libcurl_version < blobfuse_constants::minCurlVersion) {
         // Curl was not intialized for lower version as that results into
         // failure post fork. So tls and cpplite were not initialized pre-fork for lower
         // kernel version. Do the init now before starting.
@@ -681,22 +682,44 @@ void set_up_callbacks(struct fuse_operations &azs_blob_operations)
  *  If mounted then re-mounting again shall fail.
  */ 
 bool is_directory_mounted(const char* mntDir) {
-     struct mntent *mnt_ent;
-     bool found = false;
-     FILE *mnt_list;
- 
-     mnt_list = setmntent(_PATH_MOUNTED, "r");
-     while ((mnt_ent = getmntent(mnt_list))) 
-     {
-         if (!strcmp(mnt_ent->mnt_dir, mntDir) && !strcmp(mnt_ent->mnt_type, "fuse")) 
-         {
-             found = true;
-             break;
-         }
-     }
-     endmntent(mnt_list);
-     return found;
+    bool found = false;
 
+    if (!config_options.basicRemountCheck) {
+        syslog(LOG_INFO, "Using syscall to detect directory is already mounted or not");
+        struct mntent *mnt_ent;
+
+        FILE *mnt_list;
+
+        mnt_list = setmntent(_PATH_MOUNTED, "r");
+        while ((mnt_ent = getmntent(mnt_list))) 
+        {
+            if (!strcmp(mnt_ent->mnt_dir, mntDir) && !strcmp(mnt_ent->mnt_type, "fuse")) 
+            {
+                found = true;
+                break;
+            }
+        }
+        endmntent(mnt_list);
+    } else {
+        syslog(LOG_INFO, "Reading /etc/mtab to detect directory is already mounted or not");
+        ssize_t read = 0;
+        size_t len = 0;
+        char *line = NULL;
+
+        FILE *fp = fopen("/etc/mtab", "r");
+        if (fp != NULL) {
+            while ((read = getline(&line, &len, fp)) != -1) {
+                if (strstr(line, mntDir) != NULL && strstr(line, "fuse") != NULL) 
+                {
+                    found = true;
+                    break;
+                }
+            }
+        fclose(fp);
+        }
+    }
+    
+    return found;
 }
 
 /*
@@ -766,6 +789,17 @@ read_and_set_arguments(int argc, char *argv[], struct fuse_args *args)
             exit(0);
         }
 
+        config_options.basicRemountCheck = false;
+        if (cmd_options.basic_remount_check != NULL)
+        {
+            std::string remnt_chk(cmd_options.basic_remount_check);
+            if (remnt_chk == "true")
+            {
+                syslog(LOG_INFO, "Basic remount check enabled");
+                config_options.basicRemountCheck = true;
+            }
+        }
+
         if (args && args->argv && argc > 1 && 
             is_directory_mounted(argv[1])) 
         {
@@ -775,8 +809,8 @@ read_and_set_arguments(int argc, char *argv[], struct fuse_args *args)
         }
         config_options.mntPath = std::string(argv[1]);
 
-        if(!cmd_options.config_file)
-        {fprintf(stdout, "no config file");
+        if(!cmd_options.config_file) {
+            fprintf(stdout, "no config file");
             if(!cmd_options.container_name)
             {
                 syslog(LOG_CRIT, "Unable to start blobfuse, no config file provided and --container-name is not set.");
@@ -1067,6 +1101,16 @@ read_and_set_arguments(int argc, char *argv[], struct fuse_args *args)
             gSetContentType = true;
     }
 
+    config_options.preMountValidate = false;
+    if (cmd_options.pre_mount_validate != NULL) 
+    {
+        std::string val(cmd_options.pre_mount_validate);
+        if (val == "true") {
+            syslog(LOG_INFO, "Pre mount validation enabled");
+            config_options.preMountValidate = true;
+        }
+    }
+
     // Azure retry policy config
     std::size_t offset = 0;
     config_options.maxTryCount = 0;
@@ -1178,7 +1222,7 @@ int initialize_blobfuse()
     syslog(LOG_DEBUG, "Kernel version is %f", kernel_version);
     syslog(LOG_DEBUG, "libcurl version is %f", libcurl_version);
 
-    if (libcurl_version < blobfuse_constants::minCurlVersion) 
+    if (!config_options.preMountValidate && libcurl_version < blobfuse_constants::minCurlVersion) 
     {
         syslog(LOG_WARNING, "** Delaying authentication to post fork for older curl versions");
     } else {

blobfuse/include/BlobfuseGlobals.h

@@ -73,12 +73,13 @@ struct configParams
     int low_disk_threshold;
     unsigned long long cachePollTimeout;
     unsigned long long maxEviction;
-
+    
     // Azure retry policty config
     int maxTryCount;
     double maxTimeoutSeconds;
     double retryDelay;
-
+    bool basicRemountCheck;
+    bool preMountValidate;
 };
 
 // FUSE contains a specific type of command-line option parsing; here we are just following the pattern.
@@ -110,10 +111,11 @@ struct cmdlineOptions
     const char *cache_poll_timeout_msec; // Timeout for cache eviction thread in case queue is empty
     const char *max_eviction; // Maximum number of files to be deleted from cache to converse cpu
     const char *set_content_type; // Whether to set content type while upload blob
-
     const char *max_retry; // Maximum number of retries to be done
     const char *max_timeout; // Max timeout in any retry
     const char *retry_delay; // Exponential factor for each retry
+    const char *basic_remount_check; // Check for remount by reading /etc/mtab
+    const char *pre_mount_validate; // Validate storage auth before the mount
 };