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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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ce7eebe5c3
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>
100 lines
2.1 KiB
C
100 lines
2.1 KiB
C
#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdbool.h>
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#include <sys/vfs.h>
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#include <sys/mount.h>
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#include <linux/kernel.h>
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#include "debugfs.h"
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char debugfs_mountpoint[PATH_MAX + 1] = "/sys/kernel/debug";
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static const char * const debugfs_known_mountpoints[] = {
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"/sys/kernel/debug/",
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"/debug/",
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0,
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};
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static bool debugfs_found;
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/* find the path to the mounted debugfs */
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const char *debugfs_find_mountpoint(void)
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{
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const char * const *ptr;
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char type[100];
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FILE *fp;
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if (debugfs_found)
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return (const char *)debugfs_mountpoint;
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ptr = debugfs_known_mountpoints;
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while (*ptr) {
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if (debugfs_valid_mountpoint(*ptr) == 0) {
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debugfs_found = true;
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strcpy(debugfs_mountpoint, *ptr);
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return debugfs_mountpoint;
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}
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ptr++;
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}
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/* give up and parse /proc/mounts */
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fp = fopen("/proc/mounts", "r");
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if (fp == NULL)
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return NULL;
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while (fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
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debugfs_mountpoint, type) == 2) {
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if (strcmp(type, "debugfs") == 0)
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break;
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}
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fclose(fp);
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if (strcmp(type, "debugfs") != 0)
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return NULL;
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debugfs_found = true;
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return debugfs_mountpoint;
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}
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/* verify that a mountpoint is actually a debugfs instance */
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int debugfs_valid_mountpoint(const char *debugfs)
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{
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struct statfs st_fs;
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if (statfs(debugfs, &st_fs) < 0)
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return -ENOENT;
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else if (st_fs.f_type != (long) DEBUGFS_MAGIC)
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return -ENOENT;
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return 0;
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}
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/* mount the debugfs somewhere if it's not mounted */
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char *debugfs_mount(const char *mountpoint)
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{
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/* see if it's already mounted */
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if (debugfs_find_mountpoint())
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goto out;
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/* if not mounted and no argument */
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if (mountpoint == NULL) {
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/* see if environment variable set */
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mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT);
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/* if no environment variable, use default */
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if (mountpoint == NULL)
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mountpoint = "/sys/kernel/debug";
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}
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if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)
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return NULL;
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/* save the mountpoint */
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debugfs_found = true;
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strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));
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out:
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return debugfs_mountpoint;
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}
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