kernel/linux.git/lib/string_helpers.c, branch v5.15.45

string: uninline memcpy_and_pad

2021-11-21T12:44:12+00:00

commit 5c4e0a21fae877a7ef89be6dcc6263ec672372b8 upstream. When building m68k:allmodconfig, recent versions of gcc generate the following error if the length of UTS_RELEASE is less than 8 bytes. In function 'memcpy_and_pad', inlined from 'nvmet_execute_disc_identify' at drivers/nvme/target/discovery.c:268:2: arch/m68k/include/asm/string.h:72:25: error: '__builtin_memcpy' reading 8 bytes from a region of size 7 Discussions around the problem suggest that this only happens if an architecture does not provide strlen(), if -ffreestanding is provided as compiler option, and if CONFIG_FORTIFY_SOURCE=n. All of this is the case for m68k. The exact reasons are unknown, but seem to be related to the ability of the compiler to evaluate the return value of strlen() and the resulting execution flow in memcpy_and_pad(). It would be possible to work around the problem by using sizeof(UTS_RELEASE) instead of strlen(UTS_RELEASE), but that would only postpone the problem until the function is called in a similar way. Uninline memcpy_and_pad() instead to solve the problem for good. Suggested-by: Linus Torvalds Reviewed-by: Geert Uytterhoeven Acked-by: Andy Shevchenko Signed-off-by: Guenter Roeck Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

string_helpers: Escape double quotes in escape_special

2021-07-19T09:39:28+00:00

From an abstract point of view, escape_special's counterpart, unescape_special, already handles the unescaping of blackslashed double quote sequences. As a more practical example, printk indexing is an example case where this is already practically useful. Compare an example with `ESCAPE_SPECIAL | ESCAPE_SPACE`, with quotes not escaped: [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string "%s"\n" ...and the same after this patch: [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string \"%s\"\n" One can of course, alternatively, use ESCAPE_APPEND with a quote in @only, but without this patch quotes are coerced into hex or octal which can hurt readability quite significantly. I've checked uses of ESCAPE_SPECIAL and %pE across the codebase, and I'm pretty confident that this shouldn't affect any stable interfaces. Signed-off-by: Chris Down Reviewed-by: Andy Shevchenko Reviewed-by: Petr Mladek Cc: Rasmus Villemoes Acked-by: Andy Shevchenko Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/af144c5b75e41ce417386253ba2694456bc04118.1623775748.git.chris@chrisdown.name

seq_file: drop unused *_escape_mem_ascii()

2021-07-01T18:06:05+00:00

There are no more users of the seq_escape_mem_ascii() followed by string_escape_mem_ascii(). Remove them for good. Link: https://lkml.kernel.org/r/20210504180819.73127-16-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Alexander Viro Cc: Chuck Lever Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/string_helpers: allow to append additional characters to be escaped

2021-07-01T18:06:04+00:00

Introduce a new flag to append additional characters, passed in 'only' parameter, to be escaped if they fall in the corresponding class. Link: https://lkml.kernel.org/r/20210504180819.73127-7-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Alexander Viro Cc: Chuck Lever Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/string_helpers: introduce ESCAPE_NAP to escape non-ASCII and non-printable

2021-07-01T18:06:04+00:00

Some users may want to have an ASCII based filter for printable only characters, provided by conjunction of isascii() and isprint() functions. Here is the addition of a such. Link: https://lkml.kernel.org/r/20210504180819.73127-6-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Alexander Viro Cc: Chuck Lever Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/string_helpers: introduce ESCAPE_NA for escaping non-ASCII

2021-07-01T18:06:04+00:00

Some users may want to have an ASCII based filter, provided by isascii() function. Here is the addition of a such. Link: https://lkml.kernel.org/r/20210504180819.73127-5-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Alexander Viro Cc: Chuck Lever Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/string_helpers: drop indentation level in string_escape_mem()

2021-07-01T18:06:04+00:00

The only one conditional is left on the upper level, move the rest to the same level and drop indentation level. No functional changes. Link: https://lkml.kernel.org/r/20210504180819.73127-4-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Alexander Viro Cc: Chuck Lever Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/string_helpers: move ESCAPE_NP check inside 'else' branch in a loop

2021-07-01T18:06:04+00:00

Refactor code to have better readability by moving ESCAPE_NP handling inside 'else' branch in the loop. No functional change intended. Link: https://lkml.kernel.org/r/20210504180819.73127-3-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: Alexander Viro Cc: Chuck Lever Cc: "J. Bruce Fields" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: string_helpers: provide kfree_strarray()

2020-09-30T08:50:30+00:00

There's a common pattern of dynamically allocating an array of char pointers and then also dynamically allocating each string in this array. Provide a helper for freeing such a string array with one call. Signed-off-by: Bartosz Golaszewski Reviewed-by: Andy Shevchenko

lib/string_helpers: fix some kerneldoc warnings

2019-07-17T02:23:22+00:00

Due to some sad limitations in how kerneldoc comments are parsed, the documentation in lib/string_helpers.c generates these warnings: lib/string_helpers.c:236: WARNING: Unexpected indentation. lib/string_helpers.c:241: WARNING: Block quote ends without a blank line; unexpected unindent. lib/string_helpers.c:446: WARNING: Unexpected indentation. lib/string_helpers.c:451: WARNING: Block quote ends without a blank line; unexpected unindent. lib/string_helpers.c:474: WARNING: Unexpected indentation. Rework the comments to obtain something like the desired result. Link: http://lkml.kernel.org/r/20190607110952.409011ba@lwn.net Signed-off-by: Jonathan Corbet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds