perf tools: Add perf_data_file__open interface to data object

Adding perf_data_file__open interface to data object to open the
perf.data file for both read and write.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1381847254-28809-3-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

7 files changed, 158 insertions, 107 deletions

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index c873e039aafb..326a26e5fc1c 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -365,6 +365,7 @@ LIB_OBJS += $(OUTPUT)util/vdso.o
 LIB_OBJS += $(OUTPUT)util/stat.o
 LIB_OBJS += $(OUTPUT)util/record.o
 LIB_OBJS += $(OUTPUT)util/srcline.o
+LIB_OBJS += $(OUTPUT)util/data.o
 
 LIB_OBJS += $(OUTPUT)ui/setup.o
 LIB_OBJS += $(OUTPUT)ui/helpline.o
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 4ea46ffbfc1c..428e28f3e677 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -345,8 +345,6 @@ out:
 
 static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
 {
-        struct stat st;
-        int flags;
         int err, feat;
         unsigned long waking = 0;
         const bool forks = argc > 0;
@@ -355,7 +353,6 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
         struct perf_record_opts *opts = &rec->opts;
         struct perf_evlist *evsel_list = rec->evlist;
         struct perf_data_file *file = &rec->file;
-        const char *output_name = file->path;
         struct perf_session *session;
         bool disabled = false;
 
@@ -367,35 +364,6 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
         signal(SIGUSR1, sig_handler);
         signal(SIGTERM, sig_handler);
 
-        if (!output_name) {
-                if (!fstat(STDOUT_FILENO, &st) && S_ISFIFO(st.st_mode))
-                        file->is_pipe = true;
-                else
-                        file->path = output_name = "perf.data";
-        }
-        if (output_name) {
-                if (!strcmp(output_name, "-"))
-                        file->is_pipe = true;
-                else if (!stat(output_name, &st) && st.st_size) {
-                        char oldname[PATH_MAX];
-                        snprintf(oldname, sizeof(oldname), "%s.old",
-                                 output_name);
-                        unlink(oldname);
-                        rename(output_name, oldname);
-                }
-        }
-
-        flags = O_CREAT|O_RDWR|O_TRUNC;
-
-        if (file->is_pipe)
-                file->fd = STDOUT_FILENO;
-        else
-                file->fd = open(output_name, flags, S_IRUSR | S_IWUSR);
-        if (file->fd < 0) {
-                perror("failed to create output file");
-                return -1;
-        }
-
         session = perf_session__new(file, false, NULL);
         if (session == NULL) {
                 pr_err("Not enough memory for reading perf file header\n");
@@ -586,7 +554,7 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
         fprintf(stderr,
                 "[ perf record: Captured and wrote %.3f MB %s (~%" PRIu64 " samples) ]\n",
                 (double)rec->bytes_written / 1024.0 / 1024.0,
-                output_name,
+                file->path,
                 rec->bytes_written / 24);
 
         return 0;
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 752bebeac3aa..d934f707ee74 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -929,15 +929,8 @@ static int __cmd_top(struct perf_top *top)
         struct perf_record_opts *opts = &top->record_opts;
         pthread_t thread;
         int ret;
-        struct perf_data_file file = {
-                .mode = PERF_DATA_MODE_WRITE,
-        };
 
-        /*
-         * FIXME: perf_session__new should allow passing a O_MMAP, so that all this
-         * mmap reading, etc is encapsulated in it. Use O_WRONLY for now.
-         */
-        top->session = perf_session__new(&file, false, NULL);
+        top->session = perf_session__new(NULL, false, NULL);
         if (top->session == NULL)
                 return -ENOMEM;
 
diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
new file mode 100644
index 000000000000..7d09faf85cf1
--- /dev/null
+++ b/tools/perf/util/data.c
@@ -0,0 +1,120 @@
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "data.h"
+#include "util.h"
+
+static bool check_pipe(struct perf_data_file *file)
+{
+        struct stat st;
+        bool is_pipe = false;
+        int fd = perf_data_file__is_read(file) ?
+                 STDIN_FILENO : STDOUT_FILENO;
+
+        if (!file->path) {
+                if (!fstat(fd, &st) && S_ISFIFO(st.st_mode))
+                        is_pipe = true;
+        } else {
+                if (!strcmp(file->path, "-"))
+                        is_pipe = true;
+        }
+
+        if (is_pipe)
+                file->fd = fd;
+
+        return file->is_pipe = is_pipe;
+}
+
+static int check_backup(struct perf_data_file *file)
+{
+        struct stat st;
+
+        if (!stat(file->path, &st) && st.st_size) {
+                /* TODO check errors properly */
+                char oldname[PATH_MAX];
+                snprintf(oldname, sizeof(oldname), "%s.old",
+                         file->path);
+                unlink(oldname);
+                rename(file->path, oldname);
+        }
+
+        return 0;
+}
+
+static int open_file_read(struct perf_data_file *file)
+{
+        struct stat st;
+        int fd;
+
+        fd = open(file->path, O_RDONLY);
+        if (fd < 0) {
+                int err = errno;
+
+                pr_err("failed to open %s: %s", file->path, strerror(err));
+                if (err == ENOENT && !strcmp(file->path, "perf.data"))
+                        pr_err("  (try 'perf record' first)");
+                pr_err("\n");
+                return -err;
+        }
+
+        if (fstat(fd, &st) < 0)
+                goto out_close;
+
+        if (!file->force && st.st_uid && (st.st_uid != geteuid())) {
+                pr_err("file %s not owned by current user or root\n",
+                       file->path);
+                goto out_close;
+        }
+
+        if (!st.st_size) {
+                pr_info("zero-sized file (%s), nothing to do!\n",
+                        file->path);
+                goto out_close;
+        }
+
+        file->size = st.st_size;
+        return fd;
+
+ out_close:
+        close(fd);
+        return -1;
+}
+
+static int open_file_write(struct perf_data_file *file)
+{
+        if (check_backup(file))
+                return -1;
+
+        return open(file->path, O_CREAT|O_RDWR|O_TRUNC, S_IRUSR|S_IWUSR);
+}
+
+static int open_file(struct perf_data_file *file)
+{
+        int fd;
+
+        fd = perf_data_file__is_read(file) ?
+             open_file_read(file) : open_file_write(file);
+
+        file->fd = fd;
+        return fd < 0 ? -1 : 0;
+}
+
+int perf_data_file__open(struct perf_data_file *file)
+{
+        if (check_pipe(file))
+                return 0;
+
+        if (!file->path)
+                file->path = "perf.data";
+
+        return open_file(file);
+}
+
+void perf_data_file__close(struct perf_data_file *file)
+{
+        close(file->fd);
+}
diff --git a/tools/perf/util/data.h b/tools/perf/util/data.h
index ffa0186e6000..d6c262e42f47 100644
--- a/tools/perf/util/data.h
+++ b/tools/perf/util/data.h
@@ -13,6 +13,7 @@ struct perf_data_file {
         int fd;
         bool is_pipe;
         bool force;
+        unsigned long size;
         enum perf_data_mode mode;
 };
 
@@ -26,4 +27,7 @@ static inline bool perf_data_file__is_write(struct perf_data_file *file)
         return file->mode == PERF_DATA_MODE_WRITE;
 }
 
+int perf_data_file__open(struct perf_data_file *file);
+void perf_data_file__close(struct perf_data_file *file);
+
 #endif /* __PERF_DATA_H */
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index e3f63df1d57c..d857c18d2eeb 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -16,73 +16,35 @@
 #include "perf_regs.h"
 #include "vdso.h"
 
-static int perf_session__open(struct perf_session *self, bool force)
+static int perf_session__open(struct perf_session *self)
 {
-        struct stat input_stat;
-
-        if (!strcmp(self->filename, "-")) {
-                self->fd_pipe = true;
-                self->fd = STDIN_FILENO;
-
+        if (self->fd_pipe) {
                 if (perf_session__read_header(self) < 0)
                         pr_err("incompatible file format (rerun with -v to learn more)");
-
                 return 0;
         }
 
-        self->fd = open(self->filename, O_RDONLY);
-        if (self->fd < 0) {
-                int err = errno;
-
-                pr_err("failed to open %s: %s", self->filename, strerror(err));
-                if (err == ENOENT && !strcmp(self->filename, "perf.data"))
-                        pr_err("  (try 'perf record' first)");
-                pr_err("\n");
-                return -errno;
-        }
-
-        if (fstat(self->fd, &input_stat) < 0)
-                goto out_close;
-
-        if (!force && input_stat.st_uid && (input_stat.st_uid != geteuid())) {
-                pr_err("file %s not owned by current user or root\n",
-                       self->filename);
-                goto out_close;
-        }
-
-        if (!input_stat.st_size) {
-                pr_info("zero-sized file (%s), nothing to do!\n",
-                        self->filename);
-                goto out_close;
-        }
-
         if (perf_session__read_header(self) < 0) {
                 pr_err("incompatible file format (rerun with -v to learn more)");
-                goto out_close;
+                return -1;
         }
 
         if (!perf_evlist__valid_sample_type(self->evlist)) {
                 pr_err("non matching sample_type");
-                goto out_close;
+                return -1;
         }
 
         if (!perf_evlist__valid_sample_id_all(self->evlist)) {
                 pr_err("non matching sample_id_all");
-                goto out_close;
+                return -1;
         }
 
         if (!perf_evlist__valid_read_format(self->evlist)) {
                 pr_err("non matching read_format");
-                goto out_close;
+                return -1;
         }
 
-        self->size = input_stat.st_size;
         return 0;
-
-out_close:
-        close(self->fd);
-        self->fd = -1;
-        return -1;
 }
 
 void perf_session__set_id_hdr_size(struct perf_session *session)
@@ -110,35 +72,35 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
                                        bool repipe, struct perf_tool *tool)
 {
         struct perf_session *self;
-        const char *filename = file->path;
-        struct stat st;
-        size_t len;
-
-        if (!filename || !strlen(filename)) {
-                if (!fstat(STDIN_FILENO, &st) && S_ISFIFO(st.st_mode))
-                        filename = "-";
-                else
-                        filename = "perf.data";
-        }
 
-        len = strlen(filename);
-        self = zalloc(sizeof(*self) + len);
-
-        if (self == NULL)
+        self = zalloc(sizeof(*self));
+        if (!self)
                 goto out;
 
-        memcpy(self->filename, filename, len);
         self->repipe = repipe;
         INIT_LIST_HEAD(&self->ordered_samples.samples);
         INIT_LIST_HEAD(&self->ordered_samples.sample_cache);
         INIT_LIST_HEAD(&self->ordered_samples.to_free);
         machines__init(&self->machines);
 
-        if (perf_data_file__is_read(file)) {
-                if (perf_session__open(self, file->force) < 0)
+        if (file) {
+                if (perf_data_file__open(file))
                         goto out_delete;
-                perf_session__set_id_hdr_size(self);
-        } else if (perf_data_file__is_write(file)) {
+
+                self->fd       = file->fd;
+                self->fd_pipe  = file->is_pipe;
+                self->filename = file->path;
+                self->size     = file->size;
+
+                if (perf_data_file__is_read(file)) {
+                        if (perf_session__open(self) < 0)
+                                goto out_close;
+
+                        perf_session__set_id_hdr_size(self);
+                }
+        }
+
+        if (!file || perf_data_file__is_write(file)) {
                 /*
                  * In O_RDONLY mode this will be performed when reading the
                  * kernel MMAP event, in perf_event__process_mmap().
@@ -153,10 +115,13 @@ struct perf_session *perf_session__new(struct perf_data_file *file,
                 tool->ordered_samples = false;
         }
 
-out:
         return self;
-out_delete:
+
+ out_close:
+        perf_data_file__close(file);
+ out_delete:
         perf_session__delete(self);
+ out:
         return NULL;
 }
 
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index f2f6251fd62c..e1ca2d0ae541 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -39,7 +39,7 @@ struct perf_session {
         bool                    fd_pipe;
         bool                    repipe;
         struct ordered_samples  ordered_samples;
-        char                    filename[1];
+        const char              *filename;
 };
 
 #define PRINT_IP_OPT_IP         (1<<0)