chcpu: add a helper function to read the CPU 'online' bitmap

Signed-off-by: Christian Goeschel Ndjomouo <cgoesc2@wgu.edu>

diff --git a/sys-utils/chcpu.c b/sys-utils/chcpu.c
index cb0b9f5229cf0f15578e90922a873cc4f59e5ce9..f17b1a88f2dc3a448e88809f48f694799a34850e 100644 (file)
--- a/sys-utils/chcpu.c
+++ b/sys-utils/chcpu.c
@@ -233,6 +233,28 @@ static void cpu_parse(char *cpu_string, cpu_set_t *cpu_set, size_t setsize)
        errx(EXIT_FAILURE, _("failed to parse CPU list: %s"), cpu_string);
 }
 
+static void read_cpulist(struct path_cxt *sys, const char *sysroot,
+                                       cpu_set_t **cpu_set, size_t *setsize)
+{
+       if (ul_path_read_s32(sys, &maxcpus, "kernel_max") == 0)
+               maxcpus += 1;
+       else if (!sysroot)
+               maxcpus = get_max_number_of_cpus();
+
+       if (maxcpus <= 0)
+               maxcpus = 2048;
+
+       *setsize = CPU_ALLOC_SIZE(maxcpus);
+
+       if (ul_path_access(sys, F_OK, "online") == 0)
+               ul_path_readf_cpulist(sys, cpu_set, maxcpus, "online");
+       else
+               *cpu_set = CPU_ALLOC(maxcpus);
+
+       if (!*cpu_set)
+               err(EXIT_FAILURE, _("cpuset_alloc failed"));
+}
+
 static void __attribute__((__noreturn__)) usage(void)
 {
        FILE *out = stdout;
@@ -351,19 +373,7 @@ int main(int argc, char *argv[])
        if (!ul_path_is_accessible(sys))
                err(EXIT_FAILURE, _("cannot open %s"), _PATH_SYS_CPU);
 
-       maxcpus = get_max_number_of_cpus();
-       if (maxcpus < 1)
-               errx(EXIT_FAILURE, _("cannot determine NR_CPUS; aborting"));
-
-       if (ul_path_access(sys, F_OK, "online") == 0)
-               ul_path_readf_cpulist(sys, &cpu_set, maxcpus, "online");
-       else
-               cpu_set = CPU_ALLOC(maxcpus);
-       if (!cpu_set)
-               err(EXIT_FAILURE, _("cpuset_alloc failed"));
-
-       setsize = CPU_ALLOC_SIZE(maxcpus);
-
+       read_cpulist(sys, sysroot, &cpu_set, &setsize);
        if (cpu_list_arg)
                cpu_parse(cpu_list_arg, cpu_set, setsize);