GUAC-1452: Try and retry the specified filename until success or no further possibilities exist.

This commit is contained in:
Michael Jumper 2016-01-27 11:50:56 -08:00
parent 0d5355560e
commit e9fb7a67da
2 changed files with 95 additions and 8 deletions

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@ -26,6 +26,7 @@
#include <guacamole/timestamp.h>
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
@ -34,21 +35,88 @@
#include <sys/stat.h>
#include <fcntl.h>
/**
* Attempts to open a new typescript data file within the given path and having
* the given name. If such a file already exists, sequential numeric suffixes
* (.1, .2, .3, etc.) are appended until a filename is found which does not
* exist (or until the maximum number of numeric suffixes has been tried). If
* the file absolutely cannot be opened due to an error, -1 is returned and
* errno is set appropriately.
*
* @param path
* The full path to the directory in which the data file should be created.
*
* @param name
* The name of the data file which should be crated within the given path.
*
* @param basename
* A buffer in which the path, a path separator, the filename, any
* necessary suffix, and a NULL terminator will be stored. If insufficient
* space is available, -1 will be returned, and errno will be set to
* ENAMETOOLONG.
*
* @param basename_size
* The number of bytes available within the provided basename buffer.
*
* @return
* The file descriptor of the open data file if open succeeded, or -1 on
* failure.
*/
static int guac_terminal_typescript_open_data_file(const char* path,
const char* name, char* basename, int basename_size) {
int i;
/* Concatenate path and name (separated by a single slash) */
int basename_length = snprintf(basename,
basename_size - GUAC_TERMINAL_TYPESCRIPT_MAX_SUFFIX_LENGTH ,
"%s/%s", path, name);
/* Abort if maximum length reached */
if (basename_length ==
basename_size - GUAC_TERMINAL_TYPESCRIPT_MAX_SUFFIX_LENGTH) {
errno = ENAMETOOLONG;
return -1;
}
/* Attempt to open typescript data file */
int data_fd = open(basename,
O_CREAT | O_EXCL | O_WRONLY,
S_IRUSR | S_IWUSR);
/* Prepare basename for additional suffix */
basename[basename_length] = '.';
char* suffix = basename + basename_length + 1;
/* Continue retrying alternative suffixes if file already exists */
for (i = 1; data_fd == -1 && errno == EEXIST
&& i <= GUAC_TERMINAL_TYPESCRIPT_MAX_SUFFIX; i++) {
/* Append new suffix */
sprintf(suffix, "%i", i);
/* Retry with newly-suffixed filename */
data_fd = open(basename,
O_CREAT | O_EXCL | O_WRONLY,
S_IRUSR | S_IWUSR);
}
return data_fd;
}
guac_terminal_typescript* guac_terminal_typescript_alloc(const char* path,
const char* name, int create_path) {
char basename[GUAC_TERMINAL_TYPESCRIPT_MAX_NAME_LENGTH];
guac_terminal_typescript* typescript;
int data_fd, timing_fd;
/* TODO: Determing data and timing filenames prior to open() calls.
* Be sure not to use open() itself to test for existence, as that could
* result in tons of typescript data files being unnecessarily created.
*/
/* Attempt to open typescript data file */
data_fd = open("/tmp/typescript-data",
O_CREAT | O_EXCL | O_WRONLY,
S_IRUSR | S_IWUSR);
data_fd = guac_terminal_typescript_open_data_file(path, name,
basename, sizeof(basename));
if (data_fd == -1)
return NULL;

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@ -47,6 +47,25 @@
*/
#define GUAC_TERMINAL_TYPESCRIPT_MAX_DELAY 86400000
/**
* The maximum numeric value allowed for the .1, .2, .3, etc. suffix appended
* to the end of the typescript filename if a typescript having the requested
* name already exists.
*/
#define GUAC_TERMINAL_TYPESCRIPT_MAX_SUFFIX 255
/**
* The maximum length of the string containing a sequential numeric suffix
* between 1 and GUAC_TERMINAL_TYPESCRIPT_MAX_SUFFIX inclusive, in bytes.
*/
#define GUAC_TERMINAL_TYPESCRIPT_MAX_SUFFIX_LENGTH 4
/**
* The maximum overall length of the full path to the typescript file,
* including any additional suffix, in bytes.
*/
#define GUAC_TERMINAL_TYPESCRIPT_MAX_NAME_LENGTH 2048
/**
* An active typescript, consisting of a data file (raw terminal output) and
* timing file (related timestamps and byte counts).