perf srcline: Simplify addr2line subprocess

Don't wrap stdin and stdout of subprocess with streams, use the api/io
library for buffering.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tom Rix <trix@redhat.com>
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230403184033.1836023-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index f0a96a834e4b6d5fb438074c77586699e6c6009e..5339ab4c5e12367f3cc37eefe3569a69f5c407b8 100644 (file)
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -10,6 +10,8 @@
 #include <linux/string.h>
 #include <linux/zalloc.h>
 
+#include <api/io.h>
+
 #include "util/dso.h"
 #include "util/debug.h"
 #include "util/callchain.h"
@@ -366,12 +368,6 @@ void dso__free_a2l(struct dso *dso)
 
 #else /* HAVE_LIBBFD_SUPPORT */
 
-struct a2l_subprocess {
-       struct child_process addr2line;
-       FILE *to_child;
-       FILE *from_child;
-};
-
 static int filename_split(char *filename, unsigned int *line_nr)
 {
        char *sep;
@@ -393,28 +389,18 @@ static int filename_split(char *filename, unsigned int *line_nr)
        return 0;
 }
 
-static void addr2line_subprocess_cleanup(struct a2l_subprocess *a2l)
+static void addr2line_subprocess_cleanup(struct child_process *a2l)
 {
-       if (a2l->addr2line.pid != -1) {
-               kill(a2l->addr2line.pid, SIGKILL);
-               finish_command(&a2l->addr2line); /* ignore result, we don't care */
-               a2l->addr2line.pid = -1;
-       }
-
-       if (a2l->to_child != NULL) {
-               fclose(a2l->to_child);
-               a2l->to_child = NULL;
-       }
-
-       if (a2l->from_child != NULL) {
-               fclose(a2l->from_child);
-               a2l->from_child = NULL;
+       if (a2l->pid != -1) {
+               kill(a2l->pid, SIGKILL);
+               finish_command(a2l); /* ignore result, we don't care */
+               a2l->pid = -1;
        }
 
        free(a2l);
 }
 
-static struct a2l_subprocess *addr2line_subprocess_init(const char *addr2line_path,
+static struct child_process *addr2line_subprocess_init(const char *addr2line_path,
                                                        const char *binary_path)
 {
        const char *argv[] = {
@@ -422,54 +408,34 @@ static struct a2l_subprocess *addr2line_subprocess_init(const char *addr2line_pa
                "-e", binary_path,
                "-i", "-f", NULL
        };
-       struct a2l_subprocess *a2l = zalloc(sizeof(*a2l));
+       struct child_process *a2l = zalloc(sizeof(*a2l));
        int start_command_status = 0;
 
-       if (a2l == NULL)
-               goto out;
-
-       a2l->to_child = NULL;
-       a2l->from_child = NULL;
+       if (a2l == NULL) {
+               pr_err("Failed to allocate memory for addr2line");
+               return NULL;
+       }
 
-       a2l->addr2line.pid = -1;
-       a2l->addr2line.in = -1;
-       a2l->addr2line.out = -1;
-       a2l->addr2line.no_stderr = 1;
+       a2l->pid = -1;
+       a2l->in = -1;
+       a2l->out = -1;
+       a2l->no_stderr = 1;
 
-       a2l->addr2line.argv = argv;
-       start_command_status = start_command(&a2l->addr2line);
-       a2l->addr2line.argv = NULL; /* it's not used after start_command; avoid dangling pointers */
+       a2l->argv = argv;
+       start_command_status = start_command(a2l);
+       a2l->argv = NULL; /* it's not used after start_command; avoid dangling pointers */
 
        if (start_command_status != 0) {
                pr_warning("could not start addr2line (%s) for %s: start_command return code %d\n",
                        addr2line_path, binary_path, start_command_status);
-               goto out;
-       }
-
-       a2l->to_child = fdopen(a2l->addr2line.in, "w");
-       if (a2l->to_child == NULL) {
-               pr_warning("could not open write-stream to addr2line (%s) of %s\n",
-                       addr2line_path, binary_path);
-               goto out;
-       }
-
-       a2l->from_child = fdopen(a2l->addr2line.out, "r");
-       if (a2l->from_child == NULL) {
-               pr_warning("could not open read-stream from addr2line (%s) of %s\n",
-                       addr2line_path, binary_path);
-               goto out;
+               addr2line_subprocess_cleanup(a2l);
+               return NULL;
        }
 
        return a2l;
-
-out:
-       if (a2l)
-               addr2line_subprocess_cleanup(a2l);
-
-       return NULL;
 }
 
-static int read_addr2line_record(struct a2l_subprocess *a2l,
+static int read_addr2line_record(struct io *io,
                                 char **function,
                                 char **filename,
                                 unsigned int *line_nr)
@@ -494,7 +460,7 @@ static int read_addr2line_record(struct a2l_subprocess *a2l,
        if (line_nr != NULL)
                *line_nr = 0;
 
-       if (getline(&line, &line_len, a2l->from_child) < 0 || !line_len)
+       if (io__getline(io, &line, &line_len) < 0 || !line_len)
                goto error;
        if (function != NULL)
                *function = strdup(strim(line));
@@ -502,7 +468,7 @@ static int read_addr2line_record(struct a2l_subprocess *a2l,
        zfree(&line);
        line_len = 0;
 
-       if (getline(&line, &line_len, a2l->from_child) < 0 || !line_len)
+       if (io__getline(io, &line, &line_len) < 0 || !line_len)
                goto error;
 
        if (filename_split(line, line_nr == NULL ? &dummy_line_nr : line_nr) == 0) {
@@ -546,13 +512,17 @@ static int addr2line(const char *dso_name, u64 addr,
                     struct inline_node *node,
                     struct symbol *sym __maybe_unused)
 {
-       struct a2l_subprocess *a2l = dso->a2l;
+       struct child_process *a2l = dso->a2l;
        char *record_function = NULL;
        char *record_filename = NULL;
        unsigned int record_line_nr = 0;
        int record_status = -1;
        int ret = 0;
        size_t inline_count = 0;
+       int len;
+       char buf[128];
+       ssize_t written;
+       struct io io;
 
        if (!a2l) {
                if (!filename__has_section(dso_name, ".debug_line"))
@@ -578,13 +548,16 @@ static int addr2line(const char *dso_name, u64 addr,
         * though, because it may be genuinely unknown, in which case we'll get two sets of
         * "??"/"??:0" lines.
         */
-       if (fprintf(a2l->to_child, "%016"PRIx64"\n,\n", addr) < 0 || fflush(a2l->to_child) != 0) {
+       len = snprintf(buf, sizeof(buf), "%016"PRIx64"\n,\n", addr);
+       written = len > 0 ? write(a2l->in, buf, len) : -1;
+       if (written != len) {
                if (!symbol_conf.disable_add2line_warn)
                        pr_warning("%s %s: could not send request\n", __func__, dso_name);
                goto out;
        }
+       io__init(&io, a2l->out, buf, sizeof(buf));
 
-       switch (read_addr2line_record(a2l, &record_function, &record_filename, &record_line_nr)) {
+       switch (read_addr2line_record(&io, &record_function, &record_filename, &record_line_nr)) {
        case -1:
                if (!symbol_conf.disable_add2line_warn)
                        pr_warning("%s %s: could not read first record\n", __func__, dso_name);
@@ -594,7 +567,7 @@ static int addr2line(const char *dso_name, u64 addr,
                 * The first record was invalid, so return failure, but first read another
                 * record, since we asked a junk question and have to clear the answer out.
                 */
-               switch (read_addr2line_record(a2l, NULL, NULL, NULL)) {
+               switch (read_addr2line_record(&io, NULL, NULL, NULL)) {
                case -1:
                        if (!symbol_conf.disable_add2line_warn)
                                pr_warning("%s %s: could not read delimiter record\n",
@@ -632,7 +605,7 @@ static int addr2line(const char *dso_name, u64 addr,
        }
 
        /* We have to read the records even if we don't care about the inline info. */
-       while ((record_status = read_addr2line_record(a2l,
+       while ((record_status = read_addr2line_record(&io,
                                                      &record_function,
                                                      &record_filename,
                                                      &record_line_nr)) == 1) {
@@ -656,7 +629,7 @@ out:
 
 void dso__free_a2l(struct dso *dso)
 {
-       struct a2l_subprocess *a2l = dso->a2l;
+       struct child_process *a2l = dso->a2l;
 
        if (!a2l)
                return;