[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[Szabolcs Nagy]

If the host toolchain is not glibc based then the arm kernel build
fails with

 arch/arm/vdso/vdsomunge.c:53:19: fatal error: error.h: No such file or directory

error.h is a glibc only header (ie not available in musl, newlib and
bsd libcs).  Changed the error reporting to standard conforming code
to avoid depending on specific C implementations.

Signed-off-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
---
 arch/arm/vdso/vdsomunge.c |   56 ++++++++++++++++++++++++++-------------------
 1 file changed, 33 insertions(+), 23 deletions(-)

diff --git a/arch/arm/vdso/vdsomunge.c b/arch/arm/vdso/vdsomunge.c
index 9005b07..aedec81 100644
--- a/arch/arm/vdso/vdsomunge.c
+++ b/arch/arm/vdso/vdsomunge.c
@@ -45,13 +45,11 @@
  * it does.
  */

-#define _GNU_SOURCE
-
 #include <byteswap.h>
 #include <elf.h>
 #include <errno.h>
-#include <error.h>
 #include <fcntl.h>
+#include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -82,11 +80,25 @@
 #define EF_ARM_ABI_FLOAT_HARD 0x400
 #endif

+static int failed;
+static const char *argv0;
 static const char *outfile;

+static void fail(const char *fmt, ...)
+{
+	va_list ap;
+
+	failed = 1;
+	fprintf(stderr, "%s: ", argv0);
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	exit(EXIT_FAILURE);
+}
+
 static void cleanup(void)
 {
-	if (error_message_count > 0 && outfile != NULL)
+	if (failed && outfile != NULL)
 		unlink(outfile);
 }

@@ -119,68 +131,66 @@ int main(int argc, char **argv)
 	int infd;

 	atexit(cleanup);
+	argv0 = argv[0];

 	if (argc != 3)
-		error(EXIT_FAILURE, 0, "Usage: %s [infile] [outfile]", argv[0]);
+		fail("Usage: %s [infile] [outfile]\n", argv[0]);

 	infile = argv[1];
 	outfile = argv[2];

 	infd = open(infile, O_RDONLY);
 	if (infd < 0)
-		error(EXIT_FAILURE, errno, "Cannot open %s", infile);
+		fail("Cannot open %s: %s\n", infile, strerror(errno));

 	if (fstat(infd, &stat) != 0)
-		error(EXIT_FAILURE, errno, "Failed stat for %s", infile);
+		fail("Failed stat for %s: %s\n", infile, strerror(errno));

 	inbuf = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, infd, 0);
 	if (inbuf == MAP_FAILED)
-		error(EXIT_FAILURE, errno, "Failed to map %s", infile);
+		fail("Failed to map %s: %s\n", infile, strerror(errno));

 	close(infd);

 	inhdr = inbuf;

 	if (memcmp(&inhdr->e_ident, ELFMAG, SELFMAG) != 0)
-		error(EXIT_FAILURE, 0, "Not an ELF file");
+		fail("Not an ELF file\n");

 	if (inhdr->e_ident[EI_CLASS] != ELFCLASS32)
-		error(EXIT_FAILURE, 0, "Unsupported ELF class");
+		fail("Unsupported ELF class\n");

 	swap = inhdr->e_ident[EI_DATA] != HOST_ORDER;

 	if (read_elf_half(inhdr->e_type, swap) != ET_DYN)
-		error(EXIT_FAILURE, 0, "Not a shared object");
+		fail("Not a shared object\n");

-	if (read_elf_half(inhdr->e_machine, swap) != EM_ARM) {
-		error(EXIT_FAILURE, 0, "Unsupported architecture %#x",
-		      inhdr->e_machine);
-	}
+	if (read_elf_half(inhdr->e_machine, swap) != EM_ARM)
+		fail("Unsupported architecture %#x\n", inhdr->e_machine);

 	e_flags = read_elf_word(inhdr->e_flags, swap);

 	if (EF_ARM_EABI_VERSION(e_flags) != EF_ARM_EABI_VER5) {
-		error(EXIT_FAILURE, 0, "Unsupported EABI version %#x",
-		      EF_ARM_EABI_VERSION(e_flags));
+		fail("Unsupported EABI version %#x\n",
+		     EF_ARM_EABI_VERSION(e_flags));
 	}

 	if (e_flags & EF_ARM_ABI_FLOAT_HARD)
-		error(EXIT_FAILURE, 0,
-		      "Unexpected hard-float flag set in e_flags");
+		fail("Unexpected hard-float flag set in e_flags\n");

 	clear_soft_float = !!(e_flags & EF_ARM_ABI_FLOAT_SOFT);

 	outfd = open(outfile, O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
 	if (outfd < 0)
-		error(EXIT_FAILURE, errno, "Cannot open %s", outfile);
+		fail("Cannot open %s: %s\n", outfile, strerror(errno));

 	if (ftruncate(outfd, stat.st_size) != 0)
-		error(EXIT_FAILURE, errno, "Cannot truncate %s", outfile);
+		fail("Cannot truncate %s: %s\n", outfile, strerror(errno));

 	outbuf = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
 		      outfd, 0);
 	if (outbuf == MAP_FAILED)
-		error(EXIT_FAILURE, errno, "Failed to map %s", outfile);
+		fail("Failed to map %s: %s\n", outfile, strerror(errno));

 	close(outfd);

@@ -195,7 +205,7 @@ int main(int argc, char **argv)
 	}

 	if (msync(outbuf, stat.st_size, MS_SYNC) != 0)
-		error(EXIT_FAILURE, errno, "Failed to sync %s", outfile);
+		fail("Failed to sync %s: %s\n", outfile, strerror(errno));

 	return EXIT_SUCCESS;
 }
-- 
1.7.9.5

[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[Will Deacon]

On Tue, Jun 30, 2015 at 11:48:29AM +0100, Szabolcs Nagy wrote:
> If the host toolchain is not glibc based then the arm kernel build
> fails with
> 
>  arch/arm/vdso/vdsomunge.c:53:19: fatal error: error.h: No such file or directory
> 
> error.h is a glibc only header (ie not available in musl, newlib and
> bsd libcs).  Changed the error reporting to standard conforming code
> to avoid depending on specific C implementations.
> 
> Signed-off-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
> ---
>  arch/arm/vdso/vdsomunge.c |   56 ++++++++++++++++++++++++++-------------------
>  1 file changed, 33 insertions(+), 23 deletions(-)

Looks fine to me:

  Acked-by: Will Deacon <will.deacon@arm.com>

Probably worth a Cc stable too.

Will

[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[Nathan Lynch]

On 06/30/2015 06:05 AM, Will Deacon wrote:
> On Tue, Jun 30, 2015 at 11:48:29AM +0100, Szabolcs Nagy wrote:
>> If the host toolchain is not glibc based then the arm kernel build
>> fails with
>>
>>  arch/arm/vdso/vdsomunge.c:53:19: fatal error: error.h: No such file or directory
>>
>> error.h is a glibc only header (ie not available in musl, newlib and
>> bsd libcs).  Changed the error reporting to standard conforming code
>> to avoid depending on specific C implementations.
>>
>> Signed-off-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
>> ---
>>  arch/arm/vdso/vdsomunge.c |   56 ++++++++++++++++++++++++++-------------------
>>  1 file changed, 33 insertions(+), 23 deletions(-)
> 
> Looks fine to me:
> 
>   Acked-by: Will Deacon <will.deacon@arm.com>
> 
> Probably worth a Cc stable too.

Agreed and thanks; submitted to Russell's patch system as 8397/1.

[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[Russell King - ARM Linux]

On Tue, Jun 30, 2015 at 11:48:29AM +0100, Szabolcs Nagy wrote:
> @@ -82,11 +80,25 @@
>  #define EF_ARM_ABI_FLOAT_HARD 0x400
>  #endif
> 
> +static int failed;
> +static const char *argv0;
>  static const char *outfile;
> 
> +static void fail(const char *fmt, ...)
> +{
> +	va_list ap;
> +
> +	failed = 1;
> +	fprintf(stderr, "%s: ", argv0);
> +	va_start(ap, fmt);
> +	vfprintf(stderr, fmt, ap);
> +	va_end(ap);
> +	exit(EXIT_FAILURE);

What purpose does "failed" serve?  Reading through this patch, it
seems to be a write-only variable.

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[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[Nathan Lynch]

On 07/01/2015 05:27 PM, Russell King - ARM Linux wrote:
> On Tue, Jun 30, 2015 at 11:48:29AM +0100, Szabolcs Nagy wrote:
>> @@ -82,11 +80,25 @@
>>  #define EF_ARM_ABI_FLOAT_HARD 0x400
>>  #endif
>>
>> +static int failed;
>> +static const char *argv0;
>>  static const char *outfile;
>>
>> +static void fail(const char *fmt, ...)
>> +{
>> +	va_list ap;
>> +
>> +	failed = 1;
>> +	fprintf(stderr, "%s: ", argv0);
>> +	va_start(ap, fmt);
>> +	vfprintf(stderr, fmt, ap);
>> +	va_end(ap);
>> +	exit(EXIT_FAILURE);
> 
> What purpose does "failed" serve?  Reading through this patch, it
> seems to be a write-only variable.

It's checked in an atexit handler:

 static void cleanup(void)
 {
-	if (error_message_count > 0 && outfile != NULL)
+	if (failed && outfile != NULL)
 		unlink(outfile);
 }

[PATCH] ARM: fix vdsomunge not to depend on glibc specific error.h

[Russell King - ARM Linux]

On Wed, Jul 01, 2015 at 05:29:13PM -0500, Nathan Lynch wrote:
> On 07/01/2015 05:27 PM, Russell King - ARM Linux wrote:
> > On Tue, Jun 30, 2015 at 11:48:29AM +0100, Szabolcs Nagy wrote:
> >> @@ -82,11 +80,25 @@
> >>  #define EF_ARM_ABI_FLOAT_HARD 0x400
> >>  #endif
> >>
> >> +static int failed;
> >> +static const char *argv0;
> >>  static const char *outfile;
> >>
> >> +static void fail(const char *fmt, ...)
> >> +{
> >> +	va_list ap;
> >> +
> >> +	failed = 1;
> >> +	fprintf(stderr, "%s: ", argv0);
> >> +	va_start(ap, fmt);
> >> +	vfprintf(stderr, fmt, ap);
> >> +	va_end(ap);
> >> +	exit(EXIT_FAILURE);
> > 
> > What purpose does "failed" serve?  Reading through this patch, it
> > seems to be a write-only variable.
> 
> It's checked in an atexit handler:
> 
>  static void cleanup(void)
>  {
> -	if (error_message_count > 0 && outfile != NULL)
> +	if (failed && outfile != NULL)
>  		unlink(outfile);
>  }

Thx, missed that.

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