From cde164aee9e0343831467035eb96dd5506742648 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 2 Feb 2015 14:35:03 -0500 Subject: [PATCH] tools lib fs: Add helper to find mounted file systems In preparation for adding tracefs for perf to use, create a findfs helper utility that find_debugfs uses instead of hard coding the search in the code. This will allow for a find_tracefs to be used as well. Signed-off-by: Steven Rostedt Acked-by: Jiri Olsa Cc: Andrew Morton Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20150202193552.735023362@goodmis.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/api/Makefile | 2 ++ tools/lib/api/fs/debugfs.c | 51 ++++++------------------------------- tools/lib/api/fs/debugfs.h | 11 +------- tools/lib/api/fs/findfs.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++ tools/lib/api/fs/findfs.h | 21 ++++++++++++++++ 5 files changed, 94 insertions(+), 54 deletions(-) create mode 100644 tools/lib/api/fs/findfs.c create mode 100644 tools/lib/api/fs/findfs.h diff --git a/tools/lib/api/Makefile b/tools/lib/api/Makefile index 36c08b1..22b2f15 100644 --- a/tools/lib/api/Makefile +++ b/tools/lib/api/Makefile @@ -9,11 +9,13 @@ LIB_H= LIB_OBJS= LIB_H += fs/debugfs.h +LIB_H += fs/findfs.h LIB_H += fs/fs.h # See comment below about piggybacking... LIB_H += fd/array.h LIB_OBJS += $(OUTPUT)fs/debugfs.o +LIB_OBJS += $(OUTPUT)fs/findfs.o LIB_OBJS += $(OUTPUT)fs/fs.o # XXX piggybacking here, need to introduce libapikfd, or rename this # to plain libapik.a and make it have it all api goodies diff --git a/tools/lib/api/fs/debugfs.c b/tools/lib/api/fs/debugfs.c index d21d4d6..91e1668 100644 --- a/tools/lib/api/fs/debugfs.c +++ b/tools/lib/api/fs/debugfs.c @@ -20,58 +20,21 @@ static const char * const debugfs_known_mountpoints[] = { static bool debugfs_found; -/* verify that a mountpoint is actually a debugfs instance */ - -static int debugfs_valid_mountpoint(const char *debugfs) -{ - struct statfs st_fs; - - if (statfs(debugfs, &st_fs) < 0) - return -ENOENT; - else if ((long)st_fs.f_type != (long)DEBUGFS_MAGIC) - return -ENOENT; - - return 0; -} - /* find the path to the mounted debugfs */ const char *debugfs_find_mountpoint(void) { - const char * const *ptr; - char type[100]; - FILE *fp; + const char *ret; if (debugfs_found) return (const char *)debugfs_mountpoint; - ptr = debugfs_known_mountpoints; - while (*ptr) { - if (debugfs_valid_mountpoint(*ptr) == 0) { - debugfs_found = true; - strcpy(debugfs_mountpoint, *ptr); - return debugfs_mountpoint; - } - ptr++; - } + ret = find_mountpoint("debugfs", (long) DEBUGFS_MAGIC, + debugfs_mountpoint, PATH_MAX + 1, + debugfs_known_mountpoints); + if (ret) + debugfs_found = true; - /* give up and parse /proc/mounts */ - fp = fopen("/proc/mounts", "r"); - if (fp == NULL) - return NULL; - - while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n", - debugfs_mountpoint, type) == 2) { - if (strcmp(type, "debugfs") == 0) - break; - } - fclose(fp); - - if (strcmp(type, "debugfs") != 0) - return NULL; - - debugfs_found = true; - - return debugfs_mountpoint; + return ret; } /* mount the debugfs somewhere if it's not mounted */ diff --git a/tools/lib/api/fs/debugfs.h b/tools/lib/api/fs/debugfs.h index 77bb36a..1074ac8 100644 --- a/tools/lib/api/fs/debugfs.h +++ b/tools/lib/api/fs/debugfs.h @@ -1,16 +1,7 @@ #ifndef __API_DEBUGFS_H__ #define __API_DEBUGFS_H__ -#define _STR(x) #x -#define STR(x) _STR(x) - -/* - * On most systems would have given us this, but not on some systems - * (e.g. GNU/Hurd). - */ -#ifndef PATH_MAX -#define PATH_MAX 4096 -#endif +#include "findfs.h" #ifndef DEBUGFS_MAGIC #define DEBUGFS_MAGIC 0x64626720 diff --git a/tools/lib/api/fs/findfs.c b/tools/lib/api/fs/findfs.c new file mode 100644 index 0000000..49946cb --- /dev/null +++ b/tools/lib/api/fs/findfs.c @@ -0,0 +1,63 @@ +#include +#include +#include +#include +#include +#include + +#include "findfs.h" + +/* verify that a mountpoint is actually the type we want */ + +int valid_mountpoint(const char *mount, long magic) +{ + struct statfs st_fs; + + if (statfs(mount, &st_fs) < 0) + return -ENOENT; + else if ((long)st_fs.f_type != magic) + return -ENOENT; + + return 0; +} + +/* find the path to a mounted file system */ +const char *find_mountpoint(const char *fstype, long magic, + char *mountpoint, int len, + const char * const *known_mountpoints) +{ + const char * const *ptr; + char format[128]; + char type[100]; + FILE *fp; + + if (known_mountpoints) { + ptr = known_mountpoints; + while (*ptr) { + if (valid_mountpoint(*ptr, magic) == 0) { + strncpy(mountpoint, *ptr, len - 1); + mountpoint[len-1] = 0; + return mountpoint; + } + ptr++; + } + } + + /* give up and parse /proc/mounts */ + fp = fopen("/proc/mounts", "r"); + if (fp == NULL) + return NULL; + + snprintf(format, 128, "%%*s %%%ds %%99s %%*s %%*d %%*d\n", len); + + while (fscanf(fp, format, mountpoint, type) == 2) { + if (strcmp(type, fstype) == 0) + break; + } + fclose(fp); + + if (strcmp(type, fstype) != 0) + return NULL; + + return mountpoint; +} diff --git a/tools/lib/api/fs/findfs.h b/tools/lib/api/fs/findfs.h new file mode 100644 index 0000000..9e7d876 --- /dev/null +++ b/tools/lib/api/fs/findfs.h @@ -0,0 +1,21 @@ +#ifndef __API_FINDFS_H__ +#define __API_FINDFS_H__ + +#define _STR(x) #x +#define STR(x) _STR(x) + +/* + * On most systems would have given us this, but not on some systems + * (e.g. GNU/Hurd). + */ +#ifndef PATH_MAX +#define PATH_MAX 4096 +#endif + +const char *find_mountpoint(const char *fstype, long magic, + char *mountpoint, int len, + const char * const *known_mountpoints); + +int valid_mountpoint(const char *mount, long magic); + +#endif /* __API_FINDFS_H__ */ -- 2.7.4