idevicescreenshot: Choose a better filename, prevent overwriting existing files
diff --git a/tools/idevicescreenshot.c b/tools/idevicescreenshot.c
index 75a69ce..f33e83e 100644
--- a/tools/idevicescreenshot.c
+++ b/tools/idevicescreenshot.c
@@ -29,7 +29,9 @@
#include <string.h>
#include <stdlib.h>
#include <errno.h>
+#include <math.h>
#include <time.h>
+#include <unistd.h>
#ifndef WIN32
#include <signal.h>
#endif
@@ -38,6 +40,7 @@
#include <libimobiledevice/lockdown.h>
#include <libimobiledevice/screenshotr.h>
+void get_image_filename(char *imgdata, char **filename);
void print_usage(int argc, char **argv);
int main(int argc, char **argv)
@@ -117,21 +120,7 @@
char *imgdata = NULL;
uint64_t imgsize = 0;
if (screenshotr_take_screenshot(shotr, &imgdata, &imgsize) == SCREENSHOTR_E_SUCCESS) {
- if (!filename) {
- const char *fileext = NULL;
- if (memcmp(imgdata, "\x89PNG", 4) == 0) {
- fileext = ".png";
- } else if (memcmp(imgdata, "MM\x00*", 4) == 0) {
- fileext = ".tiff";
- } else {
- printf("WARNING: screenshot data has unexpected image format.\n");
- fileext = ".dat";
- }
- time_t now = time(NULL);
- filename = (char*)malloc(36);
- size_t pos = strftime(filename, 36, "screenshot-%Y-%m-%d-%H-%M-%S", gmtime(&now));
- sprintf(filename+pos, "%s", fileext);
- }
+ get_image_filename(imgdata, &filename);
FILE *f = fopen(filename, "wb");
if (f) {
if (fwrite(imgdata, 1, (size_t)imgsize, f) == (size_t)imgsize) {
@@ -162,6 +151,53 @@
return result;
}
+void get_image_filename(char *imgdata, char **filename)
+{
+ // If the provided filename already has an extension, use it as is.
+ if (*filename) {
+ char *last_dot = strrchr(*filename, '.');
+ if (last_dot && !strchr(last_dot, '/')) {
+ return;
+ }
+ }
+
+ // Find the appropriate file extension for the filename.
+ const char *fileext = NULL;
+ if (memcmp(imgdata, "\x89PNG", 4) == 0) {
+ fileext = ".png";
+ } else if (memcmp(imgdata, "MM\x00*", 4) == 0) {
+ fileext = ".tiff";
+ } else {
+ printf("WARNING: screenshot data has unexpected image format.\n");
+ fileext = ".dat";
+ }
+
+ // If a filename without an extension is provided, append the extension.
+ // Otherwise, generate a filename based on the current time.
+ char *basename = NULL;
+ if (*filename) {
+ basename = (char*)malloc(strlen(*filename) + 1);
+ strcpy(basename, *filename);
+ free(*filename);
+ } else {
+ time_t now = time(NULL);
+ basename = (char*)malloc(32);
+ strftime(basename, 31, "screenshot-%Y-%m-%d-%H-%M-%S", gmtime(&now));
+ }
+
+ // Ensure the filename is unique on disk.
+ char *unique_filename = (char*)malloc(strlen(basename) + strlen(fileext) + 1);
+ sprintf(unique_filename, "%s%s", basename, fileext);
+ int i;
+ for (i = 2; access(unique_filename, F_OK) != -1; i++) {
+ free(unique_filename);
+ unique_filename = (char*)malloc(strlen(basename) + strlen(fileext) + floor(log10(i)) + 3);
+ sprintf(unique_filename, "%s-%d%s", basename, i, fileext);
+ }
+ *filename = unique_filename;
+ free(basename);
+}
+
void print_usage(int argc, char **argv)
{
char *name = NULL;
@@ -169,10 +205,13 @@
name = strrchr(argv[0], '/');
printf("Usage: %s [OPTIONS] [FILE]\n", (name ? name + 1: argv[0]));
printf("\n");
- printf("Gets a screenshot from a device.\n");
+ printf("Gets a screenshot from a connected device.\n");
printf("\n");
- printf("The screenshot is saved as a TIFF image with the given FILE name,\n");
- printf("where the default name is \"screenshot-DATE.tiff\", e.g.:\n");
+ printf("The image is in PNG format for iOS 9+ and otherwise in TIFF format.\n");
+ printf("The screenshot is saved as an image with the given FILE name.\n");
+ printf("If FILE has no extension, FILE will be a prefix of the saved filename.\n");
+ printf("If FILE is not specified, \"screenshot-DATE\", will be used as a prefix\n");
+ printf("of the filename, e.g.:\n");
printf(" ./screenshot-2013-12-31-23-59-59.tiff\n");
printf("\n");
printf("NOTE: A mounted developer disk image is required on the device, otherwise\n");
