[PATCH] kexec.c: workaround getline and fscanf to make it *libc agnostic. Tested against klibc and dietlibc.

[Simon Horman]

On Sun, Nov 22, 2009 at 12:12:49AM +0100, Andrea Adami wrote:
> 
> Signed-off-by: Andrea Adami <andrea.adami at gmail.com>
> Signed-off-by: Yuri Bushmelev <jay4mail at gmail.com>
> ---
>  kexec/kexec.c |   38 ++++++++++++++++++++++++++++++--------
>  1 files changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/kexec/kexec.c b/kexec/kexec.c
> index ce105cd..a3ca79c 100644
> --- a/kexec/kexec.c
> +++ b/kexec/kexec.c
> @@ -933,15 +933,32 @@ void usage(void)
>  
>  static int kexec_loaded(void)
>  {
> -	int ret;
> +	long ret = -1;
>  	FILE *fp;
> +	char *p;
> +	char line[3];
>  
>  	fp = fopen("/sys/kernel/kexec_loaded", "r");
>  	if (fp == NULL)
>  		return -1;
> -	fscanf(fp, "%d", &ret);
> +/*	fscanf(fp, "%d", &ret); */

	I'm not sure this comment is needed.
	If you'd like to keep it, please indent it by one tab
	and replace the between '/*' and 'fscanf' with a single space.

	/* fscanf(fp, "%d", &ret); */

> +	p = fgets(line, sizeof(line), fp);
>  	fclose(fp);
> -	return ret;
> +
> +	if ( NULL == p)
> +		return -1;
> +
> +	ret = strtol(line, &p, 10);
> +
> +	if (ret > INT_MAX)
> +	/* Too long */

	Please remove this comment or move it to immediately
	above the if statement.

	/* Too long */
	if (ret > INT_MAX)
		...

> +		return -1;
> +
> +	if (p == line)
> +	/* No digits were found */

	Again, please remove this comment or move it to immediately
	above the if statement.

> +		return -1;
> +
> +	return (int)ret;
>  }
>  
>  /*
> @@ -989,18 +1006,23 @@ static void remove_parameter(char *line, const char *param_name)
>  char *get_command_line(void)
>  {
>  	FILE *fp;
> -	size_t len;
> -	char *line = NULL;
> +	const int sizeof_line = 1024;

	Should they type of sizeof_line be const size_t ?

> +	char *line = malloc(sizeof_line); /* according to strdup() later */

	Could line be char line[1024] ?
>  
>  	fp = fopen("/proc/cmdline", "r");
>  	if (!fp)
> -		die("Could not read /proc/cmdline.");
> -	getline(&line, &len, fp);
> +		die("Could not open /proc/cmdline.");
> +
> +	if ( NULL == fgets(line, sizeof(line), fp) ) {

	* The reverse of this logic makes more sense to me:

	  if (fgets(line, sizeof(line), fp) == NULL) {

	* Should sizeof(line) be sizeof_line?
	  Or alternatively line changed from a pointer to an array.

	  As it stands sizeof(line) == 4 (on x86_32, glibc)

> +		die("Can't read /proc/cmdline.");
> +
> +/* 	getline(&line, &len, fp); */

	Again, I don't think this comment is needed,
	but if you want to keep it please indent it by one tab
	and replace the between '/*' and 'getline' with a single space.

>  	fclose(fp);

	fclose looks like it needs to be indented by two tabs.

> +	}
>  
>  	if (line) {
>  		/* strip newline */
> -		*(line + strlen(line) - 1) = 0;
> +		line[strlen(line) - 1] = '\0';
>  
>  		remove_parameter(line, "BOOT_IMAGE");
>  		if (kexec_flags & KEXEC_ON_CRASH)
> -- 
> 1.6.4.4
> 
> 
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