| From 61636f15718edc7ea17b91f22f1d97b905eaf951 Mon Sep 17 00:00:00 2001 |
| From: Paul Barker <paul@paulbarker.me.uk> |
| Date: Sat, 7 Nov 2015 10:23:52 +0000 |
| Subject: [PATCH 4/4] opkg_download: Use short cache file name |
| |
| Source URIs can be very long. The cache directory itself may already have a very |
| long path, especially if we're installing packages into an offline rootfs. |
| Therefore it's not a good idea to simply tag the source URI onto the cache |
| directory path to create a cache file name. |
| |
| To create shorter cache file names which are deterministic and very likely to be |
| unique, we use the md5sum of the source URI along with the basename of the |
| source URI. The basename is length limited to ensure that it the resulting |
| filename length is always reasonable. |
| |
| Signed-off-by: Paul Barker <paul@paulbarker.me.uk> |
| Signed-off-by: Alejandro del Castillo <alejandro.delcastillo@ni.com> |
| |
| Upstream-Status: Accepted |
| --- |
| libopkg/opkg_download.c | 35 ++++++++++++++++++++++++++++------- |
| 1 file changed, 28 insertions(+), 7 deletions(-) |
| |
| diff --git a/libopkg/opkg_download.c b/libopkg/opkg_download.c |
| index e9b86a5..a37b10d 100644 |
| --- a/libopkg/opkg_download.c |
| +++ b/libopkg/opkg_download.c |
| @@ -29,10 +29,18 @@ |
| #include "opkg_verify.h" |
| #include "opkg_utils.h" |
| |
| +#include "md5.h" |
| #include "sprintf_alloc.h" |
| #include "file_util.h" |
| #include "xfuncs.h" |
| |
| +/* Limit the short file name used to generate cache file names to 90 characters |
| + * so that when added to the md5sum (32 characters) and an underscore, the |
| + * resulting length is below 128 characters. The maximum file name length |
| + * differs between plaforms but 128 characters should be reasonable. |
| + */ |
| +#define MAX_SHORT_FILE_NAME_LENGTH 90 |
| + |
| static int opkg_download_set_env() |
| { |
| int r; |
| @@ -135,15 +143,28 @@ int opkg_download_internal(const char *src, const char *dest, |
| */ |
| char *get_cache_location(const char *src) |
| { |
| - char *cache_name = xstrdup(src); |
| - char *cache_location, *p; |
| + unsigned char md5sum_bin[16]; |
| + char *md5sum_hex; |
| + char *cache_location; |
| + char *short_file_name; |
| + char *tmp = xstrdup(src); |
| |
| - for (p = cache_name; *p; p++) |
| - if (*p == '/') |
| - *p = '_'; |
| + md5_buffer(src, strlen(src), md5sum_bin); |
| + md5sum_hex = md5_to_string(md5sum_bin); |
| |
| - sprintf_alloc(&cache_location, "%s/%s", opkg_config->cache_dir, cache_name); |
| - free(cache_name); |
| + /* Generate a short file name which will be used along with an md5sum of the |
| + * full src URI in the cache file name. This short file name is limited to |
| + * MAX_SHORT_FILE_NAME_LENGTH to ensure that the total cache file name |
| + * length is reasonable. |
| + */ |
| + short_file_name = basename(tmp); |
| + if (strlen(short_file_name) > MAX_SHORT_FILE_NAME_LENGTH) |
| + short_file_name[MAX_SHORT_FILE_NAME_LENGTH] = '\0'; |
| + |
| + sprintf_alloc(&cache_location, "%s/%s_%s", opkg_config->cache_dir, |
| + md5sum_hex, short_file_name); |
| + free(md5sum_hex); |
| + free(tmp); |
| return cache_location; |
| } |
| |
| -- |
| 1.9.1 |
| |