diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/Makefile | 2 | ||||
| -rw-r--r-- | tools/perf/util/debugfs.c | 241 | ||||
| -rw-r--r-- | tools/perf/util/debugfs.h | 25 |
3 files changed, 268 insertions, 0 deletions
diff --git a/tools/perf/Makefile b/tools/perf/Makefile index 542b29e2e38..b9509b1cc32 100644 --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -353,6 +353,7 @@ LIB_H += util/include/asm/swab.h LIB_H += util/include/asm/system.h LIB_H += util/include/asm/uaccess.h LIB_H += perf.h +LIB_H += util/debugfs.h LIB_H += util/event.h LIB_H += util/types.h LIB_H += util/levenshtein.h @@ -378,6 +379,7 @@ LIB_OBJS += util/abspath.o LIB_OBJS += util/alias.o LIB_OBJS += util/config.o LIB_OBJS += util/ctype.o +LIB_OBJS += util/debugfs.o LIB_OBJS += util/environment.o LIB_OBJS += util/event.o LIB_OBJS += util/exec_cmd.o diff --git a/tools/perf/util/debugfs.c b/tools/perf/util/debugfs.c new file mode 100644 index 00000000000..06b73ee02c4 --- /dev/null +++ b/tools/perf/util/debugfs.c @@ -0,0 +1,241 @@ +#include "util.h" +#include "debugfs.h" +#include "cache.h" + +static int debugfs_premounted; +static char debugfs_mountpoint[MAX_PATH+1]; + +static const char *debugfs_known_mountpoints[] = { + "/sys/kernel/debug/", + "/debug/", + 0, +}; + +/* use this to force a umount */ +void debugfs_force_cleanup(void) +{ + debugfs_find_mountpoint(); + debugfs_premounted = 0; + debugfs_umount(); +} + +/* construct a full path to a debugfs element */ +int debugfs_make_path(const char *element, char *buffer, int size) +{ + int len; + + if (strlen(debugfs_mountpoint) == 0) { + buffer[0] = '\0'; + return -1; + } + + len = strlen(debugfs_mountpoint) + strlen(element) + 1; + if (len >= size) + return len+1; + + snprintf(buffer, size-1, "%s/%s", debugfs_mountpoint, element); + return 0; +} + +static int debugfs_found; + +/* find the path to the mounted debugfs */ +const char *debugfs_find_mountpoint(void) +{ + const char **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 = 1; + strcpy(debugfs_mountpoint, *ptr); + return debugfs_mountpoint; + } + ptr++; + } + + /* give up and parse /proc/mounts */ + fp = fopen("/proc/mounts", "r"); + if (fp == NULL) + die("Can't open /proc/mounts for read"); + + while (fscanf(fp, "%*s %" + STR(MAX_PATH) + "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 = 1; + + 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; +} + + +int debugfs_valid_entry(const char *path) +{ + struct stat st; + + if (stat(path, &st)) + return -errno; + + return 0; +} + +/* mount the debugfs somewhere */ + +int debugfs_mount(const char *mountpoint) +{ + char mountcmd[128]; + + /* see if it's already mounted */ + if (debugfs_find_mountpoint()) { + debugfs_premounted = 1; + return 0; + } + + /* 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"; + } + + /* save the mountpoint */ + strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint)); + + /* mount it */ + snprintf(mountcmd, sizeof(mountcmd), + "/bin/mount -t debugfs debugfs %s", mountpoint); + return system(mountcmd); +} + +/* umount the debugfs */ + +int debugfs_umount(void) +{ + char umountcmd[128]; + int ret; + + /* if it was already mounted, leave it */ + if (debugfs_premounted) + return 0; + + /* make sure it's a valid mount point */ + ret = debugfs_valid_mountpoint(debugfs_mountpoint); + if (ret) + return ret; + + snprintf(umountcmd, sizeof(umountcmd), + "/bin/umount %s", debugfs_mountpoint); + return system(umountcmd); +} + +int debugfs_write(const char *entry, const char *value) +{ + char path[MAX_PATH+1]; + int ret, count; + int fd; + + /* construct the path */ + snprintf(path, sizeof(path), "%s/%s", debugfs_mountpoint, entry); + + /* verify that it exists */ + ret = debugfs_valid_entry(path); + if (ret) + return ret; + + /* get how many chars we're going to write */ + count = strlen(value); + + /* open the debugfs entry */ + fd = open(path, O_RDWR); + if (fd < 0) + return -errno; + + while (count > 0) { + /* write it */ + ret = write(fd, value, count); + if (ret <= 0) { + if (ret == EAGAIN) + continue; + close(fd); + return -errno; + } + count -= ret; + } + + /* close it */ + close(fd); + + /* return success */ + return 0; +} + +/* + * read a debugfs entry + * returns the number of chars read or a negative errno + */ +int debugfs_read(const char *entry, char *buffer, size_t size) +{ + char path[MAX_PATH+1]; + int ret; + int fd; + + /* construct the path */ + snprintf(path, sizeof(path), "%s/%s", debugfs_mountpoint, entry); + + /* verify that it exists */ + ret = debugfs_valid_entry(path); + if (ret) + return ret; + + /* open the debugfs entry */ + fd = open(path, O_RDONLY); + if (fd < 0) + return -errno; + + do { + /* read it */ + ret = read(fd, buffer, size); + if (ret == 0) { + close(fd); + return EOF; + } + } while (ret < 0 && errno == EAGAIN); + + /* close it */ + close(fd); + + /* make *sure* there's a null character at the end */ + buffer[ret] = '\0'; + + /* return the number of chars read */ + return ret; +} diff --git a/tools/perf/util/debugfs.h b/tools/perf/util/debugfs.h new file mode 100644 index 00000000000..3cd14f9ae78 --- /dev/null +++ b/tools/perf/util/debugfs.h @@ -0,0 +1,25 @@ +#ifndef __DEBUGFS_H__ +#define __DEBUGFS_H__ + +#include <sys/mount.h> + +#ifndef MAX_PATH +# define MAX_PATH 256 +#endif + +#ifndef STR +# define _STR(x) #x +# define STR(x) _STR(x) +#endif + +extern const char *debugfs_find_mountpoint(void); +extern int debugfs_valid_mountpoint(const char *debugfs); +extern int debugfs_valid_entry(const char *path); +extern int debugfs_mount(const char *mountpoint); +extern int debugfs_umount(void); +extern int debugfs_write(const char *entry, const char *value); +extern int debugfs_read(const char *entry, char *buffer, size_t size); +extern void debugfs_force_cleanup(void); +extern int debugfs_make_path(const char *element, char *buffer, int size); + +#endif /* __DEBUGFS_H__ */ |