Em Thu, May 05, 2022 at 03:09:59PM +0530, Athira Rajeev escreveu: > /proc/cpuinfo provides information about type of processor, number > of CPU's etc. Reading /proc/cpuinfo file outputs useful information > by field name like cpu, platform, model (depending on architecture) > and its value separated by colon. > > Add new utility function "cpuinfo_field" in "util/header.c" which > accepts field name as input string to search in /proc/cpuinfo content. > This returns the first matching value as resulting string. Example, > calling the function "cpuinfo_field(platform)" in powerpc returns > the platform value. This can be used to fetch processor information > from "cpuinfo" by other utilities/testcases. > > Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com> > --- > tools/perf/util/header.c | 53 ++++++++++++++++++++++++++++++++++++++++ > tools/perf/util/header.h | 1 + > 2 files changed, 54 insertions(+) > > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c > index a27132e5a5ef..f08857f96606 100644 > --- a/tools/perf/util/header.c > +++ b/tools/perf/util/header.c > @@ -983,6 +983,59 @@ static int write_dir_format(struct feat_fd *ff, > return do_write(ff, &data->dir.version, sizeof(data->dir.version)); > } > > +/* > + * Return entry from /proc/cpuinfo > + * indicated by "search" parameter. > + */ > +char *cpuinfo_field(const char *search) > +{ > + FILE *file; > + char *buf = NULL; > + char *copy_buf = NULL, *p; > + size_t len = 0; > + > + if (!search) > + return NULL; > + > + file = fopen("/proc/cpuinfo", "r"); > + if (!file) > + return NULL; > + > + while (getline(&buf, &len, file) > 0) { > + if (!strncmp(buf, search, strlen(search)))
Can you save the search string lenght in a variable and use it instead of calling strlen() for the same buffer for each line in /proc/cpuinfo? > + break; > + } > + > + if (feof(file)) > + goto done; > + > + /* > + * Trim the new line and separate > + * value for search field from ":" > + * in cpuinfo line output. > + * Example output line: > + * platform : <value> > + */ > + copy_buf = buf; > + p = strchr(copy_buf, ':'); So you assume that this will always be there, right? Shouldn't we not assume that and check if p is NULL and bail out instead? > + > + /* Go to string after ":" */ > + copy_buf = p + 1; > + p = strchr(copy_buf, '\n'); Ditto. > + if (p) > + *p = '\0'; > + > + /* Copy the filtered string after removing space to buf */ > + strcpy(buf, strim(copy_buf)); > + > + fclose(file); > + return buf; > + > +done: Please rename this goto label to "not_found", "done" isn't intention revealing. > + free(buf); > + fclose(file); > + return NULL; > +} > /* > * Check whether a CPU is online > * > diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h > index 0eb4bc29a5a4..b0f754364bd4 100644 > --- a/tools/perf/util/header.h > +++ b/tools/perf/util/header.h > @@ -166,4 +166,5 @@ int get_cpuid(char *buffer, size_t sz); > > char *get_cpuid_str(struct perf_pmu *pmu __maybe_unused); > int strcmp_cpuid_str(const char *s1, const char *s2); > +char *cpuinfo_field(const char *search); > #endif /* __PERF_HEADER_H */ > -- > 2.35.1 -- - Arnaldo