Commit 89df62c3 authored May 26, 2023 by Ian Rogers Committed by Arnaldo Carvalho de Melo May 28, 2023

tools api fs: Avoid large static PATH_MAX arrays



Change struct fs to have a pointer to a dynamically allocated array
rather than an array. This reduces the size of fs__entries from 24,768
bytes to 240 bytes. Read paths into a stack allocated array and
strdup. Fix off-by-1 fscanf %<num>s in fs__read_mounts caught by
address sanitizer.

Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20230526183401.2326121-7-irogers@google.com


Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ross Zwisler <zwisler@chromium.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-perf-users@vger.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 1fc88e5a

tools/lib/api/fs/fs.c

+18 −7

Original line number	Diff line number	Diff line
		@@ -88,7 +88,7 @@ static const char * const bpf_fs__known_mountpoints[] = {
		struct fs {
		const char *name;
		const char * const *mounts;
		char path[PATH_MAX];
		char *path;
		bool found;
		bool checked;
		long magic;
		@@ -151,18 +151,24 @@ static bool fs__read_mounts(struct fs *fs)
		bool found = false;
		char type[100];
		FILE *fp;
		char path[PATH_MAX + 1];

		fp = fopen("/proc/mounts", "r");
		if (fp == NULL)
		return NULL;
		return false;

		while (!found &&
		fscanf(fp, "%s %" STR(PATH_MAX) "s %99s %s %d %d\n",
		fs->path, type) == 2) {
		path, type) == 2) {

		if (strcmp(type, fs->name) == 0)
		if (strcmp(type, fs->name) == 0) {
		free(fs->path);
		fs->path = strdup(path);
		if (!fs->path)
		return false;
		found = true;
		}
		}

		fclose(fp);
		fs->checked = true;
		@@ -188,8 +194,11 @@ static bool fs__check_mounts(struct fs *fs)
		ptr = fs->mounts;
		while (*ptr) {
		if (fs__valid_mount(*ptr, fs->magic) == 0) {
		free(fs->path);
		fs->path = strdup(*ptr);
		if (!fs->path)
		return false;
		fs->found = true;
		strcpy(fs->path, *ptr);
		return true;
		}
		ptr++;
		@@ -227,10 +236,12 @@ static bool fs__env_override(struct fs *fs)
		if (!override_path)
		return false;

		free(fs->path);
		fs->path = strdup(override_path);
		if (!fs->path)
		return false;
		fs->found = true;
		fs->checked = true;
		strncpy(fs->path, override_path, sizeof(fs->path) - 1);
		fs->path[sizeof(fs->path) - 1] = '\0';
		return true;
		}