diff options
Diffstat (limited to 'libbb')
| -rw-r--r-- | libbb/Kbuild.src | 3 | ||||
| -rw-r--r-- | libbb/get_cpu_count.c | 47 |
2 files changed, 50 insertions, 0 deletions
diff --git a/libbb/Kbuild.src b/libbb/Kbuild.src index 5c56700..6081ebe 100644 --- a/libbb/Kbuild.src +++ b/libbb/Kbuild.src @@ -157,6 +157,9 @@ lib-$(CONFIG_MOUNT) += find_mount_point.o lib-$(CONFIG_HWCLOCK) += rtc.o lib-$(CONFIG_RTCWAKE) += rtc.o +lib-$(CONFIG_IOSTAT) += get_cpu_count.o +lib-$(CONFIG_MPSTAT) += get_cpu_count.o + # We shouldn't build xregcomp.c if we don't need it - this ensures we don't # require regex.h to be in the include dir even if we don't need it thereby # allowing us to build busybox even if uclibc regex support is disabled. diff --git a/libbb/get_cpu_count.c b/libbb/get_cpu_count.c new file mode 100644 index 0000000..a0dcb45 --- /dev/null +++ b/libbb/get_cpu_count.c @@ -0,0 +1,47 @@ +/* vi: set sw=4 ts=4: */ +/* + * Factored out of mpstat/iostat. + * + * Copyright (C) 2010 Marek Polacek <mmpolacek@gmail.com> + * + * Licensed under GPLv2, see file License in this tarball for details. + */ +#include "libbb.h" + +/* Does str start with "cpu"? */ +int FAST_FUNC starts_with_cpu(const char *str) +{ + return ((str[0] - 'c') | (str[1] - 'p') | (str[2] - 'u')) == 0; +} + +/* + * Get number of processors. Uses /proc/stat. + * Return value 0 means one CPU and non SMP kernel. + * Otherwise N means N processor(s) and SMP kernel. + */ +unsigned FAST_FUNC get_cpu_count(void) +{ + FILE *fp; + char line[256]; + int proc_nr = -1; + + fp = xfopen_for_read("/proc/stat"); + while (fgets(line, sizeof(line), fp)) { + if (!starts_with_cpu(line)) { + if (proc_nr >= 0) + break; /* we are past "cpuN..." lines */ + continue; + } + if (line[3] != ' ') { /* "cpuN" */ + int num_proc; + if (sscanf(line + 3, "%u", &num_proc) == 1 + && num_proc > proc_nr + ) { + proc_nr = num_proc; + } + } + } + + fclose(fp); + return proc_nr + 1; +} |