Auto mount in Docker containers (#1416)

contrib/redefine_syms.lst

@@ -117,3 +117,4 @@ usleep scopelibc_usleep
 vfprintf scopelibc_vfprintf
 vsnprintf scopelibc_vsnprintf
 write scopelibc_write
+mount scopelibc_mount

src/dbg.c

@@ -39,6 +39,7 @@ bool g_ismusl = FALSE;
 bool g_isstatic = FALSE;
 bool g_isgo = FALSE;
 bool g_issighandler = FALSE;
+char g_libpath[PATH_MAX] = {};
 
 void
 dbgInit()

src/dbg.h

@@ -79,6 +79,7 @@ extern bool g_ismusl;
 extern bool g_isstatic;
 extern bool g_isgo;
 extern bool g_issighandler;
+extern char g_libpath[];
 
 void scopeLog(cfg_log_level_t, const char *, ...) PRINTF_FORMAT(2,3);
 void scopeLogHex(cfg_log_level_t, const void *, size_t, const char *, ...) PRINTF_FORMAT(4,5);

src/gocontext.S

@@ -96,6 +96,8 @@
     je   2f
     cmp  $SYS_close, %eax
     je   2f
+    cmp  $SYS_mount, %eax
+    je   2f
 
     lea  \retptr@GOTPCREL(%rip), %r13
     mov  (%r13), %r13

src/gocontext_arm.S

@@ -121,6 +121,8 @@
     b.eq 2f
     cmp  x8, #SYS_close
     b.eq 2f
+    cmp  x8, #SYS_mount
+    b.eq 2f
 
     ldr  x17, =\retptr
     ldr  x17, [x17]

src/scopestdlib.c

@@ -77,6 +77,7 @@ extern int              scopelibc_rename(const char *, const char *);
 extern int              scopelibc_remove(const char *);
 extern int              scopelibc_pipe2(int [2], int);
 extern void             scopelibc_setbuf(FILE *, char *);
+extern int              scopelibc_mount(const char *, const char *, const char *, unsigned long, const void *);
 
 // String handling operations
 extern char *              scopelibc_realpath(const char *, char *);
@@ -518,6 +519,13 @@ scope_mkdir(const char *pathname, mode_t mode) {
     return scopelibc_mkdir(pathname, mode);
 }
 
+int
+scope_mount(const char *source, const char *target,
+            const char *fstype, unsigned long flags,
+            const void *data) {
+    return scopelibc_mount(source, target, fstype, flags, data);
+}
+
 int
 scope_chdir(const char *path) {
     return scopelibc_chdir(path);

src/scopestdlib.h

@@ -162,6 +162,7 @@ int            scope_fileno(FILE *);
 int            scope_flock(int, int);
 int            scope_fstat(int, struct stat *);
 int            scope_mkdir(const char *, mode_t);
+int            scope_mount(const char *, const char *, const char *, unsigned long, const void *);
 int            scope_chdir(const char *);
 int            scope_rmdir(const char *);
 char*          scope_get_current_dir_name(void);

src/scopetypes.h

@@ -50,6 +50,8 @@ typedef enum {CFG_MTC_FS,
 #define SM_NAME "scope_anon"
 #define SCOPE_FILTER_USR_PATH ("/usr/lib/appscope/scope_filter")
 #define SCOPE_FILTER_TMP_PATH ("/tmp/appscope/scope_filter")
+#define SCOPE_SYS_PATH "/usr/lib/appscope/"
+#define SCOPE_TMP_PATH "/tmp/appscope/"
 
 typedef unsigned int bool;
 #define TRUE 1

src/transport.c

@@ -21,6 +21,7 @@
 #include "scopestdlib.h"
 #include "fn.h"
 #include "transport.h"
+#include "utils.h"
 
 // Yuck.  Avoids naming conflict between our src/wrap.c and libssl.a
 #define SSL_read SCOPE_SSL_read
@@ -1018,37 +1019,6 @@ transportConnectFile(transport_t *t)
     return 1;
 }
 
-#define EDGE_PATH_DOCKER "/var/run/appscope/appscope.sock"
-#define EDGE_PATH_DEFAULT "/opt/cribl/state/appscope.sock"
-#define READ_AND_WRITE (R_OK|W_OK)
-static char*
-edgePath(void){
-    // 1) If EDGE_PATH_DOCKER can be accessed, return that.
-    if (scope_access(EDGE_PATH_DOCKER, READ_AND_WRITE) == 0) {
-        return scope_strdup(EDGE_PATH_DOCKER);
-    }
-
-    // 2) If CRIBL_HOME is defined and can be accessed,
-    //    return $CRIBL_HOME/state/appscope.sock
-    const char *cribl_home = getenv("CRIBL_HOME");
-    if (cribl_home) {
-        char *new_path = NULL;
-        if (scope_asprintf(&new_path, "%s/%s", cribl_home, "state/appscope.sock") > 0) {
-            if (scope_access(new_path, READ_AND_WRITE) == 0) {
-                return new_path;
-            }
-            scope_free(new_path);
-        }
-    }
-
-    // 3) If EDGE_PATH_DEFAULT can be accessed, return it
-    if (scope_access(EDGE_PATH_DEFAULT, READ_AND_WRITE) == 0) {
-        return scope_strdup(EDGE_PATH_DEFAULT);
-    }
-
-    return NULL;
-}
-
 int
 transportConnect(transport_t *trans)
 {

src/utils.c

@@ -494,3 +494,105 @@ sigSafeWriteNumber(int fd, long val, int base) {
     return scope_write(fd, buf ,msgLen);
 }
 
+/*
+ * Returns normalized version string
+ * - "dev" for unofficial release
+ * - "%d.%d.%d" for official release (e.g. "1.3.0" for "v1.3.0")
+ * - "%d.%d.%d-%s%d" for candidate release (e.g. "1.3.0-rc0" for "v1.3.0-rc0")
+ */
+const char *
+libVersion(const char *version) {
+
+    if ((version == NULL) || (*version != 'v')) {
+        return "dev";
+    }
+
+    ++version;
+    size_t versionSize = scope_strlen(version);
+
+    for (int i = 0; i < versionSize; ++i) {
+        // Only digit and "." are accepted
+        if ((scope_isdigit(version[i]) == 0) && version[i] != '.' &&
+            version[i] != '-' && version[i] != 't' && version[i] != 'c' &&
+            version[i] != 'r') {
+            return "dev";
+        }
+        if (i == 0 || i == versionSize) {
+            // First and last character must be number
+            if (scope_isdigit(version[i]) == 0) {
+                return "dev";
+            }
+        }
+    }
+    return version;
+}
+
+/*
+ * The mkdir system call does not support the creation of intermediate dirs.
+ * This will walk the path and create all dirs one at a time.
+ */
+bool
+makeIntermediateDirs(const char *path, mode_t mode) {
+    char *dup_path = scope_strdup(path);
+    if (!dup_path) {
+        return FALSE;
+    }
+
+    char *curr = dup_path;
+    char *slash;
+
+    while ((slash = scope_strrchr(curr, '/'))) {
+        *slash = '\0';
+        if (scope_mkdir(dup_path, mode) == -1) {
+            if (scope_errno != EEXIST) {
+                scope_free(dup_path);
+                return FALSE;
+            }
+        }
+
+        *slash = '/';
+        curr = slash + 1;
+    }
+
+    if (scope_mkdir(dup_path, mode) == -1) {
+        if (scope_errno != EEXIST) {
+            scope_free(dup_path);
+            return FALSE;
+        }
+    }
+
+    scope_free(dup_path);
+    return TRUE;
+}
+
+#define EDGE_PATH_DOCKER "/var/run/appscope/appscope.sock"
+#define EDGE_PATH_DEFAULT "/opt/cribl/state/appscope.sock"
+#define READ_AND_WRITE (R_OK|W_OK)
+
+char *
+edgePath(void) {
+    // 1) If EDGE_PATH_DOCKER can be accessed, return that.
+    if (scope_access(EDGE_PATH_DOCKER, READ_AND_WRITE) == 0) {
+        return scope_strdup(EDGE_PATH_DOCKER);
+    }
+
+    // 2) If CRIBL_HOME is defined and can be accessed,
+    //    return $CRIBL_HOME/state/appscope.sock
+    const char *cribl_home = getenv("CRIBL_HOME");
+    if (cribl_home) {
+        char *new_path = NULL;
+        if (scope_asprintf(&new_path, "%s/%s", cribl_home, "state/appscope.sock") > 0) {
+            if (scope_access(new_path, READ_AND_WRITE) == 0) {
+                return new_path;
+            }
+            scope_free(new_path);
+        }
+    }
+
+    // 3) If EDGE_PATH_DEFAULT can be accessed, return it
+    if (scope_access(EDGE_PATH_DEFAULT, READ_AND_WRITE) == 0) {
+        return scope_strdup(EDGE_PATH_DEFAULT);
+    }
+
+    return NULL;
+}

src/utils.h

@@ -23,6 +23,10 @@ int endsWith(const char *, const char *);
 void setUUID(char *);
 void setMachineID(char *);
 
+char *edgePath(void);
+bool makeIntermediateDirs(const char *, mode_t);
+const char *libVersion(const char *);
+
 // Signal Safe API
 int sigSafeNanosleep(const struct timespec *);
 void sigSafeUtoa(unsigned long, char *, int, int *);

src/wrap.c

@@ -1731,6 +1731,24 @@ init(void)
     bool scopedFlag = FALSE;
     bool skipReadCfg = FALSE;
 
+    /*
+     * This might be able to merge with the filter file check below.
+     * However, we dont want to check a specific file. We may update
+     * how we define the filter file. So, for now, leaving them
+     * distinct.
+     *
+     * Would be nice to use an env var without the need to access
+     * a file. However, we don't rely on something like SCOPE_LIB_PATH
+     * when LD_PRELOAD alone is used.
+     */
+    if (!scope_access(SCOPE_SYS_PATH, R_OK)) {
+        scope_strncpy(g_libpath, SCOPE_SYS_PATH, sizeof(SCOPE_SYS_PATH));
+    } else if (!scope_access(SCOPE_TMP_PATH, R_OK)) {
+        scope_strncpy(g_libpath, SCOPE_TMP_PATH, sizeof(SCOPE_TMP_PATH));
+    }
+
+    scope_strncat(g_libpath, libVersion(SCOPE_VER), sizeof(SCOPE_VER));
+
     if (attachedFlag) {
         scopedFlag = TRUE;
     } else {