linux/tools/lib/lk/debugfs.c
Vinson Lee ce7eebe5c3 tools lib lk: Uninclude linux/magic.h in debugfs.c
The compilation only looks for linux/magic.h from the default include
paths, which does not include the source tree. This results in a build
error if linux/magic.h is not available or not installed.

For example, this build error occurs on CentOS 5.

$ make -C tools/lib/lk V=1
[...]
gcc -o debugfs.o -c -ggdb3 -Wall -Wextra -std=gnu99 -Werror -O6
-D_FORTIFY_SOURCE=2 -Wbad-function-cast -Wdeclaration-after-statement
-Wformat-security -Wformat-y2k -Winit-self -Wmissing-declarations
-Wmissing-prototypes -Wnested-externs -Wno-system-headers
-Wold-style-definition -Wpacked -Wredundant-decls -Wshadow
-Wstrict-aliasing=3 -Wstrict-prototypes -Wswitch-default -Wswitch-enum
-Wundef -Wwrite-strings -Wformat  -fPIC  -D_LARGEFILE64_SOURCE
-D_FILE_OFFSET_BITS=64 debugfs.c
debugfs.c:8:25: error: linux/magic.h: No such file or directory

The only symbol from linux/magic.h needed by debugfs.c is DEBUGFS_MAGIC,
and that is already defined in debugfs.h. linux/magic.h isn't providing
any extra symbols and can unincluded. This is similar to the approach by
perf, which has its own magic.h wrapper at
tools/perf/util/include/linux/magic.h

Signed-off-by: Vinson Lee <vlee@twitter.com>
Acked-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Vinson Lee <vlee@freedesktop.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1379546200-17028-1-git-send-email-vlee@freedesktop.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-09-19 15:08:53 -03:00

101 lines
2.1 KiB
C

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <sys/vfs.h>
#include <sys/mount.h>
#include <linux/kernel.h>
#include "debugfs.h"
char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
static const char * const debugfs_known_mountpoints[] = {
"/sys/kernel/debug/",
"/debug/",
0,
};
static bool debugfs_found;
/* find the path to the mounted debugfs */
const char *debugfs_find_mountpoint(void)
{
const char * const *ptr;
char type[100];
FILE *fp;
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++;
}
/* 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;
}
/* verify that a mountpoint is actually a debugfs instance */
int debugfs_valid_mountpoint(const char *debugfs)
{
struct statfs st_fs;
if (statfs(debugfs, &st_fs) < 0)
return -ENOENT;
else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
return -ENOENT;
return 0;
}
/* mount the debugfs somewhere if it's not mounted */
char *debugfs_mount(const char *mountpoint)
{
/* see if it's already mounted */
if (debugfs_find_mountpoint())
goto out;
/* if not mounted and no argument */
if (mountpoint == NULL) {
/* see if environment variable set */
mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT);
/* if no environment variable, use default */
if (mountpoint == NULL)
mountpoint = "/sys/kernel/debug";
}
if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)
return NULL;
/* save the mountpoint */
debugfs_found = true;
strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
out:
return debugfs_mountpoint;
}