shared: Generalize function to read any /proc/pid entry

Change-Id: Ide42d323a2ce6f3901d7a5c26baa9ff5153a512f

3 files changed, 61 insertions, 26 deletions

diff --git a/src/crash-manager/crash-manager.c b/src/crash-manager/crash-manager.c
index 59b0537..3cbc777 100644
--- a/src/crash-manager/crash-manager.c
+++ b/src/crash-manager/crash-manager.c
@@ -251,12 +251,26 @@ static int make_dump_dir(void)
 	return 0;
 }
 
-static int get_cmd_info(struct crash_info *cinfo)
+static bool get_cmd_info(struct crash_info *cinfo)
 {
-	cinfo->cmd_line = get_cmd_line(cinfo->pid_info);
+	assert(cinfo);
+
+	cinfo->cmd_line = malloc(PATH_MAX);
+	if (!cinfo->cmd_line)
+		return false;
+
+	if (!read_proc_file(cinfo->pid_info, "cmdline", cinfo->cmd_line, PATH_MAX, NULL))
+		goto err;
+
 	cinfo->cmd_path = get_exe_path(cinfo->pid_info);
+	if (!cinfo->cmd_path)
+		goto err;
 
-	return (cinfo->cmd_line != NULL && cinfo->cmd_path != NULL);
+	return true;
+
+err:
+	free(cinfo->cmd_line);
+	return false;
 }
 
 static int set_prstatus(struct crash_info *cinfo)
@@ -461,8 +475,7 @@ static int set_crash_info(struct crash_info *cinfo, int argc, char *argv[])
 		}
 	}
 
-	ret = get_cmd_info(cinfo);
-	if (ret <= 0) {
+	if (!get_cmd_info(cinfo)) {
 		_E("Failed to get command info");
 		return -1;
 	}
diff --git a/src/shared/util.c b/src/shared/util.c
index f3685d4..84fa25e 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -14,6 +14,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+#include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
@@ -467,36 +469,54 @@ int find_crash_tid(int pid)
 	return -1;
 }
 
-char* get_cmd_line(pid_t pid)
+bool filter_drop_trailing_whitespace(char *buf, int size, int datalen)
 {
-	char cmdline_path[PATH_MAX];
+	assert(buf);
+	assert(datalen <= size);
 
-	snprintf(cmdline_path, sizeof(cmdline_path),
-			"/proc/%d/cmdline", pid);
+	bool filtered = false;
 
-	int fd = open(cmdline_path, O_RDONLY);
-	if (fd < 0) {
-		_E("Failed to open %s: %m\n", cmdline_path);
-		return NULL;
+	for (int i = datalen; i >= 0 && isspace(buf[i]); --i) {
+		buf[i] = '\0';
+		filtered = true;
 	}
 
-	char buffer[PATH_MAX];
-	ssize_t ret = read(fd, buffer, sizeof(buffer) - 1);
-	close(fd);
+	return filtered;
+}
 
-	if (ret <= 0) {
-		_E("Failed to read %s: %m\n", cmdline_path);
-		return NULL;
+bool read_proc_file(pid_t pid, const char * const file, char *outbuf, size_t bufsize, charp0filter filter)
+{
+	assert(file);
+	assert(outbuf);
+	assert(bufsize > 0);
+
+	char path[PATH_MAX];
+
+	snprintf(path, sizeof(path), "/proc/%d/%s", pid, file);
+
+	int fd = open(path, O_RDONLY);
+	if (fd < 0) {
+		_E("Failed to open %s: %m\n", path);
+		return false;
 	}
-	buffer[ret] = '\0';
 
-	char *result;
-	if (asprintf(&result, "%s", buffer) == -1) {
-		_E("asprintf() error: %m\n");
-		return NULL;
+	ssize_t ret = read(fd, outbuf, bufsize - 1);
+	if (ret < 0) {
+		_E("Failed to read %s: %m\n", path);
+		goto err_close;
 	}
+	outbuf[ret] = '\0';
 
-	return result;
+	close(fd);
+
+	if (ret > 0 && filter)
+		(void)filter(outbuf, bufsize, ret - 1);
+
+	return true;
+
+err_close:
+	close(fd);
+	return false;
 }
 
 char* get_exe_path(pid_t pid)
diff --git a/src/shared/util.h b/src/shared/util.h
index 561c8bb..0f81ca7 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -60,7 +60,9 @@ int find_crash_tid(int pid);
 
 char* get_exe_path(pid_t pid);
 
-char* get_cmd_line(pid_t pid);
+typedef bool (*charp0filter)(char *buf, int size, int datalen);
+bool filter_drop_trailing_whitespace(char *buf, int size, int datalen);
+bool read_proc_file(pid_t pid, const char * const file, char *outbuf, size_t bufsize, charp0filter filter);
 
 char* concatenate(char *const vec[]);