perf tools: Allow overriding sysfs and proc finding with env var

SYSFS_PATH and PROC_PATH environment variables now let the user override
the detection of sysfs and proc locations for testing purposes.

Signed-off-by: Cody P Schafer <dev@codyps.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1401236684-10579-2-git-send-email-dev@codyps.com
Signed-off-by: Jiri Olsa <jolsa@kernel.org>

1 files changed, 42 insertions, 1 deletions

diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c
index 5b5eb788996e..c1b49c36a951 100644
--- a/tools/lib/api/fs/fs.c
+++ b/tools/lib/api/fs/fs.c
@@ -1,8 +1,10 @@
 /* TODO merge/factor in debugfs.c here */
 
+#include <ctype.h>
 #include <errno.h>
 #include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/vfs.h>
 
@@ -96,12 +98,51 @@ static bool fs__check_mounts(struct fs *fs)
         return false;
 }
 
+static void mem_toupper(char *f, size_t len)
+{
+        while (len) {
+                *f = toupper(*f);
+                f++;
+                len--;
+        }
+}
+
+/*
+ * Check for "NAME_PATH" environment variable to override fs location (for
+ * testing). This matches the recommendation in Documentation/sysfs-rules.txt
+ * for SYSFS_PATH.
+ */
+static bool fs__env_override(struct fs *fs)
+{
+        char *override_path;
+        size_t name_len = strlen(fs->name);
+        /* name + "_PATH" + '\0' */
+        char upper_name[name_len + 5 + 1];
+        memcpy(upper_name, fs->name, name_len);
+        mem_toupper(upper_name, name_len);
+        strcpy(&upper_name[name_len], "_PATH");
+
+        override_path = getenv(upper_name);
+        if (!override_path)
+                return false;
+
+        fs->found = true;
+        strncpy(fs->path, override_path, sizeof(fs->path));
+        return true;
+}
+
 static const char *fs__get_mountpoint(struct fs *fs)
 {
+        if (fs__env_override(fs))
+                return fs->path;
+
         if (fs__check_mounts(fs))
                 return fs->path;
 
-        return fs__read_mounts(fs) ? fs->path : NULL;
+        if (fs__read_mounts(fs))
+                return fs->path;
+
+        return NULL;
 }
 
 static const char *fs__mountpoint(int idx)