From 0d754b823cfd6b9a9ed8f072277b1b5bea6e44a4 Mon Sep 17 00:00:00 2001 From: Elliott Hughes Date: Tue, 9 Jul 2019 16:08:16 -0700 Subject: dd: iflags, oflags, fix ^C, fix the fundamental loop. Investigating why the toybox tar tests fail on Android with toybox dd, I realized I was rewriting a part of dd I'd rewritten before! This is a re-send of my 2019-02-22 patch, rebased against the current ToT... This patch was originally motivated because after suggesting to the author of https://stackoverflow.com/questions/17157820/access-vdsolinux/54797221#54797221 that he could tell dd to work in bytes rather than blocks, I realized that our dd doesn't actually support that. But the rewrite of the main loop is necessary to fix the incorrect output from the dd calls in the tar test. Without this patch, `yes | dd bs=65536 count=1 > fweep` basically gives random output, based on how many bytes the pipe feels like giving you in your first read. (As far as I know, dd *without* bs= was fine, but I can't guarantee that that's true, just that I haven't seen it fail.) Also switch to TAGGED_ARRAY and comma_* for conv rather than add two more copies of an undesired idiom. It turned out -- contrary to the belief of cp(1) -- that comma_scan isn't suitable for this because of its magic handling of "no" prefixes. (It's actually harmless in cp because none of the --preserve options begin with "no", but some dd options do.) To this end, comma_remove is a less-magic comma_scan. I've also changed an `if` to a `while` because other implementations allow things like `--preserve=mode,mode` or `conv=sync,sync`. (If we decide this is a bug rather than a feature, we should at least fix the error message to be clear that we're rejecting the *duplication*, not the option itself.) I've also fixed the ^C behavior by simply adding a direct SIGINT handler rather than trying to be clever inside the read loop (which is why we weren't handling the SIGINT until the read returned). I've also removed `strstarteq` and just added the '=' to each literal when calling regular `strstart`. Plus basic tests. --- lib/commas.c | 22 +++++++++++++++++++++- lib/lib.h | 1 + 2 files changed, 22 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/commas.c b/lib/commas.c index 03b2e345..22676847 100644 --- a/lib/commas.c +++ b/lib/commas.c @@ -59,7 +59,7 @@ char *comma_iterate(char **list, int *len) return start; } -// check all instances of opt and "no"opt in optlist, return true if opt +// Check all instances of opt and "no"opt in optlist, return true if opt // found and last instance wasn't no. If clean, remove each instance from list. int comma_scan(char *optlist, char *opt, int clean) { @@ -97,3 +97,23 @@ int comma_scanall(char *optlist, char *scanlist) return i; } + +// Returns true and removes `opt` from `optlist` if present, false otherwise. +// Doesn't have the magic "no" behavior of comma_scan. +int comma_remove(char *optlist, char *opt) +{ + int optlen = strlen(opt), len, got = 0; + + if (optlist) for (;;) { + char *s = comma_iterate(&optlist, &len); + + if (!s) break; + if (optlen == len && !strncmp(opt, s, optlen)) { + got = 1; + if (optlist) memmove(s, optlist, strlen(optlist)+1); + else *s = 0; + } + } + + return got; +} diff --git a/lib/lib.h b/lib/lib.h index b74cfbff..e354a82a 100644 --- a/lib/lib.h +++ b/lib/lib.h @@ -366,6 +366,7 @@ void comma_collate(char **old, char *new); char *comma_iterate(char **list, int *len); int comma_scan(char *optlist, char *opt, int clean); int comma_scanall(char *optlist, char *scanlist); +int comma_remove(char *optlist, char *opt); // deflate.c -- cgit v1.2.3