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author | Alan Dunn <amdunn@google.com> | 2016-02-24 08:12:25 -0800 |
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committer | Sam Mendoza-Jonas <sam@mendozajonas.com> | 2016-03-15 14:10:22 +1100 |
commit | 939660528bf1568c55b6dcf982cc9020c1dbcdd2 (patch) | |
tree | 7163c3684434f644537ea253b95305fe9b2ec466 /discover/parser.h | |
parent | 6e5cd61065181460be8152a73dfc79f94ecd27fe (diff) | |
download | talos-petitboot-939660528bf1568c55b6dcf982cc9020c1dbcdd2.tar.gz talos-petitboot-939660528bf1568c55b6dcf982cc9020c1dbcdd2.zip |
Change parser interface to allow stat
Currently, the GRUB2 parser incorrectly reports "[ -f <path> ]" as
false if the size of the file is above 1 MB. This patch changes the
parser interface to allow stating files (with parser_stat_file). Then
in the implementation of "[ -f <path> ]", we can use parser_stat_file
instead of parser_request_file which has the size limitation. I
eliminate parser_check_dir in lieu of this new interface, which has
the side effect of making "[ -d <path> ]" work (the error code for
stat was not checked correctly before).
I add a basic test for the test file operations -f, -s, and -d (to
show that my changes to test file operations do not break them) and
minorly modify the test framework to ensure it has enough fidelity to
cause the expected results. Unfortunately the test wouldn't have
caught the issue with -d, since the test framework stubs out the
parser interface itself. Nor can the test framework catch the initial
problem with -f because the imposed limit is (transitively) in
function parser_request_file.
Note that -f and -d follow symlinks despite the fact that GRUB does
not (see
http://lists.gnu.org/archive/html/grub-devel/2016-02/msg00142.html
discussing GRUB's behavior). This is not a change to Petitboot's
behavior though.
Tested:
The test test-grub2-test-file-ops passes. I booted Petitboot against
a GRUB snippet:
status=success
if [ ! -f /large_file -a $status = success ]
then status=fail_large_file
fi
if [ ! -d /a_directory -a $status = success ]
then status=fail_dir
fi
menuentry $status {
linux /vmlinux
}
(after making /large_file a file of size > 1 MiB and /a_directory a
directory) and the menuentry had title "success", as desired.
Signed-off-by: Alan Dunn <amdunn@google.com>
Signed-off-by: Sam Mendoza-Jonas <sam@mendozajonas.com>
Diffstat (limited to 'discover/parser.h')
-rw-r--r-- | discover/parser.h | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/discover/parser.h b/discover/parser.h index e0e8dc6..fc165c5 100644 --- a/discover/parser.h +++ b/discover/parser.h @@ -2,6 +2,9 @@ #define _PARSER_H #include <stdbool.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> #include "device-handler.h" @@ -51,8 +54,9 @@ int parse_user_event(struct discover_context *ctx, struct event *event); /* File IO functions for parsers; these should be the only interface that * parsers use to access a device's filesystem. * - * These are intended for small amounts of data, typically text configuration - * and state files. + * These are intended for small amounts of data, typically text + * configuration and state files. Note that parser_request_file, + * and parser_replace_file work only on non-directories. */ int parser_request_file(struct discover_context *ctx, struct discover_device *dev, const char *filename, @@ -62,7 +66,15 @@ int parser_replace_file(struct discover_context *ctx, char *buf, int len); int parser_request_url(struct discover_context *ctx, struct pb_url *url, char **buf, int *len); -int parser_check_dir(struct discover_context *ctx, - struct discover_device *dev, const char *dirname); +/* parser_stat_path returns 0 if path can be stated on dev by the + * running user. Note that this function follows symlinks, like the + * stat system call. When the function returns 0, also fills in + * statbuf for the path. Returns non-zero on error. This function + * does not have the limitations on file size that the functions above + * do. Unlike some of the functions above, this function also works + * on directories. */ +int parser_stat_path(struct discover_context *ctx, + struct discover_device *dev, const char *path, + struct stat *statbuf); #endif /* _PARSER_H */ |