[PATCH 11/15] perf test: Skip shebang and SPDX comments in shell test descriptions

[Ian Rogers <irogers@google.com>]

When extracting shell test descriptions in tests-scripts.c, the parser
skipped the first line assuming it was the shebang (#!/bin/sh) and then read
the first comment line on line 2 as the test description.

However, checkpatch.pl expects shell scripts to declare their SPDX license
identifier on line 2 (# SPDX-License-Identifier: ...). This caused the test
harness to extract the SPDX license string as the test description.

Refactor shell_test__description to use io__getline, skipping both shebang
and SPDX comment lines. This allows shell tests to include standard SPDX
headers without breaking test suite description extraction.

Assisted-by: Gemini-CLI:Google Gemini 3
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/tests-scripts.c | 81 ++++++++++++++++++--------------
 1 file changed, 46 insertions(+), 35 deletions(-)

diff --git a/tools/perf/tests/tests-scripts.c b/tools/perf/tests/tests-scripts.c
index f18c4cd337c8..7466c1e8d920 100644
--- a/tools/perf/tests/tests-scripts.c
+++ b/tools/perf/tests/tests-scripts.c
@@ -31,6 +31,7 @@ static int shell_tests__dir_fd(void)
 {
 	struct stat st;
 	char path[PATH_MAX], path2[PATH_MAX], *exec_path;
+	ssize_t len;
 	static const char * const devel_dirs[] = {
 		"./tools/perf/tests/shell",
 		"./tests/shell",
@@ -47,13 +48,17 @@ static int shell_tests__dir_fd(void)
 	}
 
 	/* Use directory of executable */
-	if (readlink("/proc/self/exe", path2, sizeof path2) < 0)
+	len = readlink("/proc/self/exe", path2, sizeof(path2) - 1);
+	if (len < 0)
 		return -1;
+	path2[len] = '\0';
 	/* Follow another level of symlink if there */
 	if (lstat(path2, &st) == 0 && (st.st_mode & S_IFMT) == S_IFLNK) {
-		scnprintf(path, sizeof(path), path2);
-		if (readlink(path, path2, sizeof path2) < 0)
+		scnprintf(path, sizeof(path), "%s", path2);
+		len = readlink(path, path2, sizeof(path2) - 1);
+		if (len < 0)
 			return -1;
+		path2[len] = '\0';
 	}
 	/* Get directory */
 	p = strrchr(path2, '/');
@@ -78,43 +83,49 @@ static int shell_tests__dir_fd(void)
 static char *shell_test__description(int dir_fd, const char *name)
 {
 	struct io io;
-	char buf[128], desc[256];
-	int ch, pos = 0;
+	char buf[128], *line = NULL;
+	size_t line_len = 0;
+	ssize_t len;
+	char *desc = NULL;
 
 	io__init(&io, openat(dir_fd, name, O_RDONLY), buf, sizeof(buf));
 	if (io.fd < 0)
 		return NULL;
 
-	/* Skip first line - should be #!/bin/bash Shebang */
-	if (io__get_char(&io) != '#')
-		goto err_out;
-	if (io__get_char(&io) != '!')
-		goto err_out;
-	do {
-		ch = io__get_char(&io);
-		if (ch < 0)
-			goto err_out;
-	} while (ch != '\n');
-
-	do {
-		ch = io__get_char(&io);
-		if (ch < 0)
-			goto err_out;
-	} while (ch == '#' || isspace(ch));
-	while (ch > 0 && ch != '\n') {
-		desc[pos++] = ch;
-		if (pos >= (int)sizeof(desc) - 1)
+	while ((len = io__getline(&io, &line, &line_len)) > 0) {
+		char *p = line;
+
+		/* Skip leading whitespace */
+		while (*p && isspace(*p))
+			p++;
+
+		/* Must be a comment */
+		if (*p != '#')
+			continue;
+		p++;
+
+		/* Skip shebang or SPDX lines */
+		if (*p == '!' || strstr(p, "SPDX-License-Identifier:"))
+			continue;
+
+		/* Skip whitespace after # */
+		while (*p && isspace(*p))
+			p++;
+
+		/* If we found non-empty text, this is the description! */
+		if (*p && *p != '\n') {
+			char *end = p + strlen(p);
+
+			while (end > p && isspace(end[-1]))
+				end--;
+			*end = '\0';
+			desc = strdup(p);
 			break;
-		ch = io__get_char(&io);
+		}
 	}
-	while (pos > 0 && isspace(desc[--pos]))
-		;
-	desc[++pos] = '\0';
-	close(io.fd);
-	return strdup(desc);
-err_out:
+	free(line);
 	close(io.fd);
-	return NULL;
+	return desc;
 }
 
 /* Is this full file path a shell script */
@@ -178,9 +189,9 @@ static void append_script(int dir_fd, const char *name, char *desc,
 	char *exclusive;
 
 	snprintf(link, sizeof(link), "/proc/%d/fd/%d", getpid(), dir_fd);
-	len = readlink(link, filename, sizeof(filename));
-	if (len < 0) {
-		pr_err("Failed to readlink %s", link);
+	len = readlink(link, filename, sizeof(filename) - 1);
+	if (len < 0 || (size_t)len >= sizeof(filename) - strlen(name) - 2) {
+		pr_err("Failed to readlink %s or path too long", link);
 		return;
 	}
 	filename[len++] = '/';
-- 
2.54.0.823.g6e5bcc1fc9-goog