zipl/src: Implement '--dry-run' option for ngdumps

Use the directory specified by the shell environment variable TMPDIR
for temporary objects creation and ngdump job simulation. If TMPDIR is
not set, then use "/tmp" for the mentioned purposes;

While running ngdump job in 'dry-run' mode:
. Don't format/mount the target dump device. Instead, create the
  bootmap file and the meta-file at the temporary mount point without
  mounting anything to it. Thus, the mentioned files to be acrually
  created in the "proxy" file system owning the temporary mount point;
. Retrieve base disk info from the read-only dump device and
  complete that info with the block size of the proxy file system;

Separate the steps on retrieving/setting file system block size
into a dedicated procedure;

Use definitions instead of hardcoded file names;

Fix a bug in an error path (accessing freed memory);

Make misc_open_simulate() and misc_open_exclusive() static;

Update man pages with the requirements on the system environment
(resources) for ngdump job being executed in dry-run mode;

Provide hints for user (in stderr) in case when ngdump job in dry-run
mode failed due to inappropriate system environment.

Tested-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Reviewed-by: Mikhail Zaslonko <zaslonko@linux.ibm.com>
Signed-off-by: Eduard Shishkin <edward6@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

zipl/include/disk.h

@@ -19,6 +19,8 @@
 #include "zipl.h"
 #include "lib/vtoc.h"
 
+#define FS_MAP_ERROR    "Could not get file mapping"
+
 
 /* Type for representing disk block numbers */
 typedef uint64_t blocknum_t;
@@ -102,6 +104,7 @@ int disk_type_is_eckd_ldl(struct disk_ext_type *ext_type);
 int disk_type_is_nvme(struct disk_ext_type *ext_type);
 int disk_type_is_eckd(disk_type_t type);
 
+int disk_info_set_fs_block(const char *filename, struct disk_info *info);
 int disk_get_info_from_file(const char* filename,
 			    struct job_target_data* target,
 			    struct disk_info** info);

zipl/include/error.h

@@ -20,5 +20,6 @@ void error_text(const char* fmt, ...);
 void error_clear_reason(void);
 void error_clear_text(void);
 void error_print(void);
+int is_error(const char *this);
 
 #endif /* not ERROR_H */

zipl/include/job.h

@@ -261,5 +261,6 @@ int check_job_images_ngdump(struct job_dump_data* dump, char* name);
 void job_dump_check_set_ngdump(struct job_data *job,
 			       struct disk_ext_type *ext_type);
 bool job_dump_is_ngdump(struct job_data *job);
+void ngdump_delete_meta(const char *path);
 
 #endif /* not JOB_H */

zipl/include/misc.h

@@ -33,8 +33,6 @@ void* misc_malloc(size_t size);
 int misc_asprintf(char **out, const char *fmt, ...);
 void* misc_calloc(size_t n, size_t size);
 char* misc_strdup(const char* s);
-int misc_open_exclusive(const char* filename);
-int misc_open_simulate(const char *filename, struct misc_fd *mfd);
 int misc_open_device(const char *filename, struct misc_fd *mfd, int simulate);
 int misc_read(int fd, void* buffer, size_t count);
 int misc_read_file(const char* filename, char** buffer, size_t* size,
@@ -49,7 +47,7 @@ int misc_get_file_buffer(const char* filename,
 			 struct misc_file_buffer* buffer);
 void misc_free_file_buffer(struct misc_file_buffer* file);
 int misc_get_char(struct misc_file_buffer* file, off_t readahead);
-char* misc_make_path(char* dirname, char* filename);
+char *misc_make_path(const char *dirname, char *filename);
 int misc_temp_dev(dev_t dev, int blockdev, char** devno);
 int misc_temp_dev_from_file(char* file, char** devno);
 void misc_free_temp_dev(char* device);

zipl/include/zipl.h

@@ -25,7 +25,9 @@
 
 #define BOOTMAP_FILENAME		"bootmap"
 #define BOOTMAP_TEMPLATE_FILENAME	"bootmap_temp.XXXXXX"
+#define DUMP_TEMP_MOUNT_POINT_DIR	"/tmp"
 #define DUMP_TEMP_MOUNT_POINT_NAME	"zipl-dump-mount-point-XXXXXX"
+#define DUMP_META_FILE_NAME		"ngdump.meta"
 
 #define DEFAULTBOOT_SECTION		"defaultboot"
 

zipl/man/zipl.8.in

@@ -366,6 +366,13 @@ error-checking is still done.
 Note that when working with tapes, the current device position will be changed
 even when specifying this option.
 
+When working with ngdumps, the directory specified by the shell environment
+variable TMPDIR is used for simulating the dump job. This directory should
+belong to a "real" file system managing disk space addresses (like ext4, or
+xfs), and have enough free space (matching the size of the specified dump
+device). If TMPDIR is not set, then "/tmp" is used, which can lead to errors,
+e.g. in case when it belongs to tmpfs.
+
 .TP
 .BR "\-f" " or " "\-\-force"
 Omit validity checking while producing a multi-volume dump.

zipl/src/bootmap.c

@@ -1542,11 +1542,39 @@ static int prepare_build_program_table_file(struct job_data *job,
 		return -1;
 	}
 	bis->tmp_filename_created = 1;
-	/* Retrieve target device information. Note that we have to
-	 * call disk_get_info_from_file() to also get the file system
-	 * block size. */
-	if (disk_get_info_from_file(bis->filename, &job->target, &bis->info))
-		return -1;
+	/*
+	 * Retrieve target device information and
+	 * complete the info with the file system block size
+	 */
+	if (job->id == job_dump_partition && dry_run) {
+		/*
+		 * ngdump job in dry-run mode.
+		 *
+		 * The dump device has read-only status.
+		 * The bootmap and the meta-file to be created
+		 * directly at the temporary mount point wthout
+		 * mounting anything to it (thus, the mentioned
+		 * files to be actually created in the "proxy"
+		 * file system.
+		 *
+		 * Retrieve info from the dump device
+		 * Retrieve file system block size from the proxy
+		 * file system
+		 */
+		if (disk_get_info(job->data.dump.device,
+				  &job->target, &bis->info))
+			return -1;
+		if (disk_info_set_fs_block(bis->filename, bis->info))
+			return -1;
+	} else {
+		/*
+		 * ngdump or ipl job.
+		 */
+		if (disk_get_info_from_file(bis->filename,
+					    &job->target,
+					    &bis->info))
+			return -1;
+	}
 	if (!disk_is_appropriate(job, bis->info))
 		return -1;
 	if (verbose) {
@@ -1627,8 +1655,17 @@ static int bootmap_create_file(struct job_data *job, struct install_set *bis,
 	return 0;
 }
 
+void ngdump_delete_meta(const char *dir)
+{
+	char *filename = NULL;
+
+	filename = misc_make_path(dir, DUMP_META_FILE_NAME);
+	unlink(filename);
+	free(filename);
+}
+
 /**
- * Create a file with the short name "ngdump.meta" in the directory PATH.
+ * Create a file with the short name DUMP_META_FILE_NAME in the directory PATH.
  * This file is required for NGDump stand-alone dumper, it's read/written
  * by the dumper when it starts.
  */
@@ -1638,13 +1675,13 @@ static int ngdump_create_meta(const char *path)
 	FILE *fp;
 	int rc;
 
-	util_asprintf(&filename, "%s/ngdump.meta", path);
+	filename = misc_make_path(path, DUMP_META_FILE_NAME);
 
 	fp = fopen(filename, "w");
 	if (!fp) {
-		free(filename);
 		error_reason(strerror(errno));
 		error_text("Could not create file '%s'", filename);
+		free(filename);
 		return -1;
 	}
 	free(filename);
@@ -1665,6 +1702,40 @@ static int ngdump_create_meta(const char *path)
 	return 0;
 }
 
+static int ngdump_mount_device(struct job_data *job)
+{
+	if (dry_run)
+		/*
+		 * the bootmap and the meta-file to be stored
+		 * directly at the temporary mount point without
+		 * mounting any partition
+		 */
+		return 0;
+	/*
+	 * the bootmap and the meta-file to be stored on the
+	 * formatted and mounted dump partition
+	 */
+	if (mount(job->data.dump.device, job->target.bootmap_dir,
+		  NGDUMP_FSTYPE, 0, NULL)) {
+		error_reason(strerror(errno));
+		error_text("Could not mount partition '%s':",
+			   job->data.dump.device);
+		return -1;
+	}
+	job->dump_mounted = 1;
+	return 0;
+}
+
+static char *ngdump_dir(void)
+{
+	return getenv("TMPDIR") ? : DUMP_TEMP_MOUNT_POINT_DIR;
+}
+
+static char *build_mount_point_pathname(void)
+{
+	return misc_make_path(ngdump_dir(), DUMP_TEMP_MOUNT_POINT_NAME);
+}
+
 static int prepare_bootloader_ngdump(struct job_data *job,
 				     struct install_set *bis)
 {
@@ -1679,8 +1750,7 @@ static int prepare_bootloader_ngdump(struct job_data *job,
 		return -1;
 
 	assert(!job->target.bootmap_dir);
-	job->target.bootmap_dir = misc_make_path("/tmp",
-						 DUMP_TEMP_MOUNT_POINT_NAME);
+	job->target.bootmap_dir = build_mount_point_pathname();
 	if (!job->target.bootmap_dir) {
 		error_reason(strerror(errno));
 		error_text("Could not make path for '%s'",
@@ -1695,25 +1765,20 @@ static int prepare_bootloader_ngdump(struct job_data *job,
 		return -1;
 	}
 	job->bootmap_dir_created = 1;
-	/*
-	 * Mount partition where bootmap file and also a dump file will
-	 * be stored.
-	 */
-	if (mount(job->data.dump.device, job->target.bootmap_dir,
-		  NGDUMP_FSTYPE, 0, NULL)) {
-		error_reason(strerror(errno));
-		error_text("Could not mount partition '%s':",
-			   job->data.dump.device);
+	if (ngdump_mount_device(job))
 		return -1;
-	}
-	job->dump_mounted = 1;
 	/*
 	 * Build a single program table for List-Directed IPL
 	 * See comments before install_bootloader() for details
 	 */
 	bis->print_details = 1;
-	if (bootmap_create_file(job, bis, BLKPTR_FORMAT_ID))
+	if (bootmap_create_file(job, bis, BLKPTR_FORMAT_ID)) {
+		if (dry_run && is_error(FS_MAP_ERROR))
+			fprintf(stderr,
+				"'%s' doesn't satisfy the requirements. Set TMPDIR properly\n",
+				ngdump_dir());
 		return -1;
+	}
 	return ngdump_create_meta(job->target.bootmap_dir);
 }
 

zipl/src/disk.c

@@ -811,20 +811,15 @@ int disk_type_is_eckd(disk_type_t type)
 		type == disk_type_eckd_cdl);
 }
 
-int
-disk_get_info_from_file(const char* filename, struct job_target_data* target,
-			struct disk_info** info)
+/**
+ * Retrieve and set block size of the file system which contains FILENAME
+ */
+int disk_info_set_fs_block(const char *filename, struct disk_info *info)
 {
-	struct stat stats;
-	char* device;
 	int blocksize;
 	int fd;
 	int rc;
 
-	if (stat(filename, &stats)) {
-		error_reason(strerror(errno));
-		return -1;
-	}
 	/* Retrieve file system block size */
 	fd = open(filename, O_RDONLY);
 	if (fd == -1) {
@@ -838,17 +833,33 @@ disk_get_info_from_file(const char* filename, struct job_target_data* target,
 			     filename);
 		return -1;
 	}
-	/* Create temporary device file */
-	rc = misc_temp_dev(stats.st_dev, 1, &device);
-	if (rc)
+	info->fs_block_size = blocksize;
+	return 0;
+}
+
+/**
+ * Retrieve disk info of the device which contains FILENAME
+ * and set the filesystem block size
+ */
+int disk_get_info_from_file(const char *filename,
+			    struct job_target_data *target,
+			    struct disk_info **info)
+{
+	struct stat stats;
+	char *device;
+
+	if (stat(filename, &stats)) {
+		error_reason(strerror(errno));
 		return -1;
-	/* Get device info */
-	rc = disk_get_info(device, target, info);
-	if (rc == 0)
-		(*info)->fs_block_size = blocksize;
-	/* Clean up */
+	}
+	if (misc_temp_dev(stats.st_dev, 1, &device))
+		return -1;
+	if (disk_get_info(device, target, info)) {
+		misc_free_temp_dev(device);
+		return -1;
+	}
 	misc_free_temp_dev(device);
-	return rc;
+	return disk_info_set_fs_block(filename, *info);
 }
 
 void disk_free_info(struct disk_info *info)

zipl/src/error.c

@@ -82,3 +82,8 @@ error_print(void)
 	else
 		fprintf(stderr, "Error: An unspecified error occurred\n");
 }
+
+int is_error(const char *this)
+{
+	return strcmp(error_reason_string, this) == 0;
+}

zipl/src/fs-map.c

@@ -96,7 +96,7 @@ int fs_map(int fd, uint64_t offset, blocknum_t *mapped,
 		/* FIEMAP failed, fall back to FIBMAP */
 		block = offset / fs_block_size;
 		if (ioctl(fd, FIBMAP, &block)) {
-			error_reason("Could not get file mapping");
+			error_reason(FS_MAP_ERROR);
 			free(fiemap);
 			return -1;
 		}

zipl/src/install.c

@@ -1119,8 +1119,9 @@ install_dump(const char *device, struct job_target_data *target, uint64_t mem,
 
 	stage2dump_parms.mem_upper_limit = mem;
 	stage2dump_parms.no_compress = no_compress;
-	mfd.fd = misc_open_exclusive(device);
-	if (mfd.fd == -1) {
+
+	/* Check if @device is a tape device */
+	if (misc_open_device(device, &mfd, 0) == -1) {
 		error_text("Could not open dump device '%s'", device);
 		return -1;
 	}

zipl/src/job.c

@@ -459,17 +459,24 @@ free_mvdump_data(struct job_mvdump_data* data)
 		free(data->device[i]);
 }
 
-
-void
-job_free(struct job_data* job)
+void job_free(struct job_data *job)
 {
-
-	if (job->dump_mounted && umount(job->target.bootmap_dir))
-		fprintf(stderr, "Could not umount dump device at %s",
-			job->target.bootmap_dir);
-	if (job->bootmap_dir_created && rmdir(job->target.bootmap_dir))
-		fprintf(stderr, "Could not remove directory %s",
-			job->target.bootmap_dir);
+	if (job->dump_mounted && umount(job->target.bootmap_dir)) {
+		fprintf(stderr,
+			"Could not umount dump device at %s(%s)\n",
+			job->target.bootmap_dir,
+			strerror(errno));
+	}
+	if (job->bootmap_dir_created) {
+		/* remove the meta-file created in dry-run mode */
+		ngdump_delete_meta(job->target.bootmap_dir);
+		if (rmdir(job->target.bootmap_dir)) {
+			fprintf(stderr,
+				"Could not remove directory %s(%s)\n",
+				job->target.bootmap_dir,
+				strerror(errno));
+		}
+	}
 	free_target_data(&job->target);
 	free_envblk_data(&job->envblk);
 	free(job->name);

zipl/src/misc.c

@@ -88,8 +88,7 @@ misc_strdup(const char* s)
 
 
 /* Open file exclusive */
-int
-misc_open_exclusive(const char* filename)
+static int misc_open_exclusive(const char *filename)
 {
 	int fd;
 
@@ -104,7 +103,7 @@ misc_open_exclusive(const char* filename)
 /**
  * Open file FILENAME for write simulation
  */
-int misc_open_simulate(const char *filename, struct misc_fd *mfd)
+static int misc_open_simulate(const char *filename, struct misc_fd *mfd)
 {
 	/*
 	 * In write simulation mode actual data are not written to the file,
@@ -301,7 +300,7 @@ misc_get_char(struct misc_file_buffer* file, off_t readahead)
 
 
 char*
-misc_make_path(char* dirname, char* filename)
+misc_make_path(const char *dirname, char *filename)
 {
 	char* result;
 	size_t len;