add slurp_proc_file()

Resolves: bz2060824
Upstream: git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
Conflicts: None

commit 193e51deccc62544f6423eb5e5eefc8a23aad679
Author: Sven Schnelle <svens@linux.ibm.com>
Date:   Thu Dec 16 12:43:54 2021 +0100

    add slurp_proc_file()

    slurp_file() cannot be used to read proc files, as they are returning
    a size of zero in stat(). Add a function slurp_proc_file() which is
    similar to slurp_file(), but doesn't require the size of the file to
    be known.

    Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
    Signed-off-by: Simon Horman <horms@verge.net.au>

Signed-off-by: Philipp Rudo <prudo@redhat.com>

kexec-tools-2.0.23-03-add_slurp_proc_file_.patch

@@ -0,0 +1,76 @@
+ commit 193e51deccc62544f6423eb5e5eefc8a23aad679
+ Author: Sven Schnelle <svens@linux.ibm.com>
+ Date:   Thu Dec 16 12:43:54 2021 +0100
+ 
+     add slurp_proc_file()
+     
+     slurp_file() cannot be used to read proc files, as they are returning
+     a size of zero in stat(). Add a function slurp_proc_file() which is
+     similar to slurp_file(), but doesn't require the size of the file to
+     be known.
+     
+     Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
+     Signed-off-by: Simon Horman <horms@verge.net.au>
+ 
+ diff --git a/kexec/kexec.c b/kexec/kexec.c
+ index f63b36b771eb95a93f07a7c286c4974a558aec8d..f3adac517161d448552a16fd79488c1df100d356 100644
+ --- a/kexec/kexec.c
+ +++ b/kexec/kexec.c
+ @@ -1106,6 +1106,57 @@ static void remove_parameter(char *line, const char *param_name)
+  	}
+  }
+  
+ +static ssize_t _read(int fd, void *buf, size_t count)
+ +{
+ +	ssize_t ret, offset = 0;
+ +
+ +	do {
+ +		ret = read(fd, buf + offset, count - offset);
+ +		if (ret < 0) {
+ +			if ((errno == EINTR) ||	(errno == EAGAIN))
+ +				continue;
+ +			return ret;
+ +		}
+ +		offset += ret;
+ +	} while (ret && offset < count);
+ +
+ +	return offset;
+ +}
+ +
+ +static char *slurp_proc_file(const char *filename, size_t *len)
+ +{
+ +	ssize_t ret, startpos = 0;
+ +	unsigned int size = 64;
+ +	char *buf = NULL, *tmp;
+ +	int fd;
+ +
+ +	fd = open(filename, O_RDONLY);
+ +	if (fd == -1)
+ +		return NULL;
+ +
+ +	do {
+ +		size *= 2;
+ +		tmp = realloc(buf, size);
+ +		if (!tmp) {
+ +			free(buf);
+ +			return NULL;
+ +		}
+ +		buf = tmp;
+ +
+ +		ret = _read(fd, buf + startpos, size - startpos);
+ +		if (ret < 0) {
+ +			free(buf);
+ +			return NULL;
+ +		}
+ +
+ +		startpos += ret;
+ +
+ +	} while(ret);
+ +
+ +	*len = startpos;
+ +	return buf;
+ +}
+ +
+  /*
+   * Returns the contents of the current command line to be used with
+   * --reuse-cmdline option.  The function gets called from architecture specific

kexec-tools.spec

@@ -106,6 +106,7 @@ Requires:       systemd-udev%{?_isa}
 #
 Patch401: ./kexec-tools-2.0.23-01-s390_add_variable_command_line_size.patch
 Patch402: ./kexec-tools-2.0.23-02-s390_use_KEXEC_ALL_OPTIONS.patch
+Patch403: ./kexec-tools-2.0.23-03-add_slurp_proc_file_.patch
 
 #
 # Patches 501 through 600 are meant for ARM kexec-tools enablement
@@ -138,6 +139,7 @@ tar -z -x -v -f %{SOURCE19}
 
 %patch401 -p1
 %patch402 -p1
+%patch403 -p1
 %patch601 -p1
 %patch602 -p1
 %patch603 -p1