failtest: generic cleanup hooks
authorRusty Russell <rusty@rustcorp.com.au>
Tue, 15 Feb 2011 12:51:42 +0000 (23:21 +1030)
committerRusty Russell <rusty@rustcorp.com.au>
Tue, 15 Feb 2011 12:51:42 +0000 (23:21 +1030)
Each function in the history stores a cleanup function, rather than storing
extra structures.  In particular, we save writes and file offsets using
this.

ccan/failtest/failtest.c
ccan/failtest/failtest.h
ccan/failtest/failtest_override.h
ccan/failtest/failtest_proto.h
ccan/failtest/test/run-history.c
ccan/failtest/test/run-open.c

index 4f71a63dc172896928cde965277b145093c13869..09b92b601c6cb8f36c6b5f3a6b59a583cd66b7d8 100644 (file)
@@ -40,18 +40,9 @@ struct write_info_hdr {
        int fd;
 };
 
-struct fd_orig {
-       int fd;
-       off_t offset;
-       size_t size;
-       bool dupped;
-};
-
 struct write_info {
        struct write_info_hdr hdr;
        char *data;
-       size_t oldlen;
-       char *olddata;
 };
 
 struct lock_info {
@@ -74,9 +65,6 @@ static unsigned int writes_num = 0;
 static struct write_info *child_writes = NULL;
 static unsigned int child_writes_num = 0;
 
-static struct fd_orig *fd_orig = NULL;
-static unsigned int fd_orig_num = 0;
-
 static pid_t lock_owner;
 static struct lock_info *locks = NULL;
 static unsigned int lock_num = 0;
@@ -100,6 +88,7 @@ static struct failtest_call *add_history_(enum failtest_call_type type,
        history[history_num].type = type;
        history[history_num].file = file;
        history[history_num].line = line;
+       history[history_num].cleanup = NULL;
        memcpy(&history[history_num].u, elem, elem_size);
        return &history[history_num++];
 }
@@ -107,22 +96,8 @@ static struct failtest_call *add_history_(enum failtest_call_type type,
 #define add_history(type, file, line, elem) \
        add_history_((type), (file), (line), (elem), sizeof(*(elem)))
 
-static void save_fd_orig(int fd)
-{
-       unsigned int i;
-
-       for (i = 0; i < fd_orig_num; i++)
-               if (fd_orig[i].fd == fd)
-                       return;
-
-       fd_orig = realloc(fd_orig, (fd_orig_num + 1) * sizeof(*fd_orig));
-       fd_orig[fd_orig_num].fd = fd;
-       fd_orig[fd_orig_num].dupped = false;
-       fd_orig[fd_orig_num].offset = lseek(fd, 0, SEEK_CUR);
-       fd_orig[fd_orig_num].size = lseek(fd, 0, SEEK_END);
-       lseek(fd, fd_orig[fd_orig_num].offset, SEEK_SET);
-       fd_orig_num++;
-}
+#define set_cleanup(call, clean, type)                 \
+       (call)->cleanup = (void *)((void)sizeof(clean((type *)NULL)), (clean))
 
 bool failtest_default_hook(struct failtest_call *history, unsigned num)
 {
@@ -413,6 +388,11 @@ static bool should_fail(struct failtest_call *call)
        return false;
 }
 
+static void cleanup_calloc(struct calloc_call *call)
+{
+       free(call->ret);
+}
+
 void *failtest_calloc(size_t nmemb, size_t size,
                      const char *file, unsigned line)
 {
@@ -427,11 +407,17 @@ void *failtest_calloc(size_t nmemb, size_t size,
                p->error = ENOMEM;
        } else {
                p->u.calloc.ret = calloc(nmemb, size);
+               set_cleanup(p, cleanup_calloc, struct calloc_call);
        }
        errno = p->error;
        return p->u.calloc.ret;
 }
 
+static void cleanup_malloc(struct malloc_call *call)
+{
+       free(call->ret);
+}
+
 void *failtest_malloc(size_t size, const char *file, unsigned line)
 {
        struct failtest_call *p;
@@ -444,11 +430,49 @@ void *failtest_malloc(size_t size, const char *file, unsigned line)
                p->error = ENOMEM;
        } else {
                p->u.calloc.ret = malloc(size);
+               set_cleanup(p, cleanup_malloc, struct malloc_call);
        }
        errno = p->error;
        return p->u.calloc.ret;
 }
 
+static void cleanup_realloc(struct realloc_call *call)
+{
+       free(call->ret);
+}
+
+/* Walk back and find out if we got this ptr from a previous routine. */
+static void fixup_ptr_history(void *ptr, unsigned int last)
+{
+       int i;
+
+       /* Start at end of history, work back. */
+       for (i = last - 1; i >= 0; i--) {
+               switch (history[i].type) {
+               case FAILTEST_REALLOC:
+                       if (history[i].u.realloc.ret == ptr) {
+                               history[i].cleanup = NULL;
+                               return;
+                       }
+                       break;
+               case FAILTEST_MALLOC:
+                       if (history[i].u.malloc.ret == ptr) {
+                               history[i].cleanup = NULL;
+                               return;
+                       }
+                       break;
+               case FAILTEST_CALLOC:
+                       if (history[i].u.calloc.ret == ptr) {
+                               history[i].cleanup = NULL;
+                               return;
+                       }
+                       break;
+               default:
+                       break;
+               }
+       }
+}
+
 void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
 {
        struct failtest_call *p;
@@ -461,12 +485,25 @@ void *failtest_realloc(void *ptr, size_t size, const char *file, unsigned line)
                p->u.realloc.ret = NULL;
                p->error = ENOMEM;
        } else {
+               fixup_ptr_history(ptr, history_num-1);
                p->u.realloc.ret = realloc(ptr, size);
+               set_cleanup(p, cleanup_realloc, struct realloc_call);
        }
        errno = p->error;
        return p->u.realloc.ret;
 }
 
+void failtest_free(void *ptr)
+{
+       fixup_ptr_history(ptr, history_num);
+       free(ptr);
+}
+
+static void cleanup_open(struct open_call *call)
+{
+       close(call->ret);
+}
+
 int failtest_open(const char *pathname,
                  const char *file, unsigned line, ...)
 {
@@ -491,11 +528,21 @@ int failtest_open(const char *pathname,
                p->error = EACCES;
        } else {
                p->u.open.ret = open(pathname, call.flags, call.mode);
+               set_cleanup(p, cleanup_open, struct open_call);
+               p->u.open.dup_fd = p->u.open.ret;
        }
        errno = p->error;
        return p->u.open.ret;
 }
 
+static void cleanup_pipe(struct pipe_call *call)
+{
+       if (!call->closed[0])
+               close(call->fds[0]);
+       if (!call->closed[1])
+               close(call->fds[1]);
+}
+
 int failtest_pipe(int pipefd[2], const char *file, unsigned line)
 {
        struct failtest_call *p;
@@ -508,6 +555,8 @@ int failtest_pipe(int pipefd[2], const char *file, unsigned line)
                p->error = EMFILE;
        } else {
                p->u.pipe.ret = pipe(p->u.pipe.fds);
+               p->u.pipe.closed[0] = p->u.pipe.closed[1] = false;
+               set_cleanup(p, cleanup_pipe, struct pipe_call);
        }
        /* This causes valgrind to notice if they use pipefd[] after failure */
        memcpy(pipefd, p->u.pipe.fds, sizeof(p->u.pipe.fds));
@@ -515,6 +564,11 @@ int failtest_pipe(int pipefd[2], const char *file, unsigned line)
        return p->u.pipe.ret;
 }
 
+static void cleanup_read(struct read_call *call)
+{
+       lseek(call->fd, call->off, SEEK_SET);
+}
+
 ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
                       const char *file, unsigned line)
 {
@@ -526,16 +580,13 @@ ssize_t failtest_pread(int fd, void *buf, size_t count, off_t off,
        call.off = off;
        p = add_history(FAILTEST_READ, file, line, &call);
 
-       /* This is going to change seek offset, so save it. */
-       if (control_fd != -1)
-               save_fd_orig(fd);
-
        /* FIXME: Try partial read returns. */
        if (should_fail(p)) {
                p->u.read.ret = -1;
                p->error = EIO;
        } else {
                p->u.read.ret = pread(fd, buf, count, off);
+               set_cleanup(p, cleanup_read, struct read_call);
        }
        errno = p->error;
        return p->u.read.ret;
@@ -547,40 +598,63 @@ static struct write_info *new_write(void)
        return &writes[writes_num++];
 }
 
+static void cleanup_write(struct write_call *call)
+{
+       lseek(call->dup_fd, call->off, SEEK_SET);
+       write(call->dup_fd, call->saved_contents, call->saved_len);
+       lseek(call->dup_fd, call->off, SEEK_SET);
+       ftruncate(call->dup_fd, call->old_filelen);
+       free(call->saved_contents);
+}
+
 ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
                        const char *file, unsigned line)
 {
        struct failtest_call *p;
        struct write_call call;
-       off_t offset;
 
-       call.fd = fd;
+       call.fd = call.dup_fd = fd;
        call.buf = buf;
        call.count = count;
        call.off = off;
        p = add_history(FAILTEST_WRITE, file, line, &call);
 
-       offset = lseek(fd, 0, SEEK_CUR);
+       /* Save old contents if we can */
+       if (p->u.write.off != -1) {
+               ssize_t ret;
+               p->u.write.old_filelen = lseek(fd, 0, SEEK_END);
+
+               /* Write past end of file?  Nothing to save.*/
+               if (p->u.write.old_filelen <= p->u.write.off)
+                       p->u.write.saved_len = 0;
+               /* Write which goes over end of file?  Partial save. */
+               else if (p->u.write.off + count > p->u.write.old_filelen)
+                       p->u.write.saved_len = p->u.write.old_filelen
+                               - p->u.write.off;
+               /* Full save. */
+               else
+                       p->u.write.saved_len = count;
+
+               p->u.write.saved_contents = malloc(p->u.write.saved_len);
+               lseek(fd, p->u.write.off, SEEK_SET);
+               ret = read(fd, p->u.write.saved_contents, p->u.write.saved_len);
+               if (ret != p->u.write.saved_len)
+                       err(1, "Expected %i bytes, got %i",
+                           (int)p->u.write.saved_len, (int)ret);
+               lseek(fd, p->u.write.off, SEEK_SET);
+               set_cleanup(p, cleanup_write, struct write_call);
+       }
 
-       /* If we're a child, save contents and tell parent about write. */
+       /* If we're a child, tell parent about write. */
        if (control_fd != -1) {
                struct write_info *winfo = new_write();
                enum info_type type = WRITE;
 
-               save_fd_orig(fd);
-
                winfo->hdr.len = count;
                winfo->hdr.fd = fd;
                winfo->data = malloc(count);
                memcpy(winfo->data, buf, count);
-               winfo->hdr.offset = offset;
-               if (winfo->hdr.offset != (off_t)-1) {
-                       lseek(fd, offset, SEEK_SET);
-                       winfo->olddata = malloc(count);
-                       winfo->oldlen = read(fd, winfo->olddata, count);
-                       if (winfo->oldlen == -1)
-                               winfo->oldlen = 0;
-               }
+               winfo->hdr.offset = off;
                write_all(control_fd, &type, sizeof(type));
                write_all(control_fd, &winfo->hdr, sizeof(winfo->hdr));
                write_all(control_fd, winfo->data, count);
@@ -596,10 +670,10 @@ ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
                        if (child_writes[0].hdr.fd != fd)
                                errx(1, "Child wrote to fd %u, not %u?",
                                     child_writes[0].hdr.fd, fd);
-                       if (child_writes[0].hdr.offset != offset)
+                       if (child_writes[0].hdr.offset != p->u.write.off)
                                errx(1, "Child wrote to offset %zu, not %zu?",
                                     (size_t)child_writes[0].hdr.offset,
-                                    (size_t)offset);
+                                    (size_t)p->u.write.off);
                        if (child_writes[0].hdr.len != count)
                                errx(1, "Child wrote length %zu, not %zu?",
                                     child_writes[0].hdr.len, count);
@@ -615,7 +689,7 @@ ssize_t failtest_pwrite(int fd, const void *buf, size_t count, off_t off,
 
                        /* Is this is a socket or pipe, child wrote it
                           already. */
-                       if (offset == (off_t)-1) {
+                       if (p->u.write.off == (off_t)-1) {
                                p->u.write.ret = count;
                                errno = p->error;
                                return p->u.write.ret;
@@ -707,21 +781,55 @@ add_lock(struct lock_info *locks, int fd, off_t start, off_t end, int type)
 /* We only trap this so we can dup fds in case we need to restore. */
 int failtest_close(int fd)
 {
-       unsigned int i;
-       int newfd = -1;
-
-       for (i = 0; i < fd_orig_num; i++) {
-               if (fd_orig[i].fd == fd) {
-                       fd_orig[i].fd = newfd = dup(fd);
-                       fd_orig[i].dupped = true;
+       int new_fd = -1, i;
+
+       if (fd < 0)
+               return close(fd);
+
+       /* Trace history to find source of fd, and if we need to cleanup writes. */
+       for (i = history_num-1; i >= 0; i--) {
+               switch (history[i].type) {
+               case FAILTEST_WRITE:
+                       if (history[i].u.write.fd != fd)
+                               break;
+                       if (!history[i].cleanup)
+                               break;
+                       /* We need to save fd so we can restore file. */
+                       if (new_fd == -1)
+                               new_fd = dup(fd);
+                       history[i].u.write.dup_fd = new_fd;
+                       break;
+               case FAILTEST_READ:
+                       /* We don't need to cleanup reads on closed fds. */
+                       if (history[i].u.read.fd != fd)
+                               break;
+                       history[i].cleanup = NULL;
+                       break;
+               case FAILTEST_PIPE:
+                       /* From a pipe?  We don't ever restore pipes... */
+                       if (history[i].u.pipe.fds[0] == fd) {
+                               assert(new_fd == -1);
+                               history[i].u.pipe.closed[0] = true;
+                               goto out;
+                       }
+                       if (history[i].u.pipe.fds[1] == fd) {
+                               assert(new_fd == -1);
+                               history[i].u.pipe.closed[1] = true;
+                               goto out;
+                       }
+                       break;
+               case FAILTEST_OPEN:
+                       if (history[i].u.open.ret == fd) {
+                               history[i].u.open.dup_fd = new_fd;
+                               goto out;
+                       }
+                       break;
+               default:
+                       break;
                }
        }
 
-       for (i = 0; i < writes_num; i++) {
-               if (writes[i].hdr.fd == fd)
-                       writes[i].hdr.fd = newfd;
-       }
-
+out:
        locks = add_lock(locks, fd, 0, off_max(), F_UNLCK);
        return close(fd);
 }
@@ -823,11 +931,10 @@ static void free_everything(void)
 
        for (i = 0; i < writes_num; i++) {
                free(writes[i].data);
-               if (writes[i].hdr.offset != (off_t)-1)
-                       free(writes[i].olddata);
        }
        free(writes);
-       free(fd_orig);
+
+       /* We don't do this in cleanup: needed even for failed opens. */
        for (i = 0; i < history_num; i++) {
                if (history[i].type == FAILTEST_OPEN)
                        free((char *)history[i].u.open.pathname);
@@ -837,7 +944,7 @@ static void free_everything(void)
 
 void failtest_exit(int status)
 {
-       unsigned int i;
+       int i;
 
        if (control_fd == -1) {
                free_everything();
@@ -849,26 +956,10 @@ void failtest_exit(int status)
                        child_fail(NULL, 0, "failtest_exit_check failed\n");
        }
 
-       /* Restore any stuff we overwrote. */
-       for (i = 0; i < writes_num; i++) {
-               if (writes[i].hdr.offset == (off_t)-1)
-                       continue;
-               if (writes[i].oldlen != 0) {
-                       lseek(writes[i].hdr.fd, writes[i].hdr.offset,
-                             SEEK_SET);
-                       write(writes[i].hdr.fd, writes[i].olddata,
-                             writes[i].oldlen);
-               }
-       }
-
-       /* Fix up fd offsets, restore sizes. */
-       for (i = 0; i < fd_orig_num; i++) {
-               lseek(fd_orig[i].fd, fd_orig[i].offset, SEEK_SET);
-               ftruncate(fd_orig[i].fd, fd_orig[i].size);
-               /* Free up any file descriptors we dup'ed. */
-               if (fd_orig[i].dupped)
-                       close(fd_orig[i].fd);
-       }
+       /* Cleanup everything, in reverse order. */
+       for (i = history_num - 1; i >= 0; i--)
+               if (history[i].cleanup)
+                       history[i].cleanup(&history[i].u);
 
        free_everything();
        tell_parent(SUCCESS);
index e8bf10ab5f6c46e056833610fd8c57b54bb1e3d5..21bc9f7c59e342fd12dec4140314b252d364763c 100644 (file)
@@ -64,19 +64,21 @@ struct open_call {
        const char *pathname;
        int flags;
        mode_t mode;
+       int dup_fd;
 };
 
 struct pipe_call {
        int ret;
        int fds[2];
+       bool closed[2];
 };
 
 struct read_call {
        ssize_t ret;
+       off_t off;
        int fd;
        void *buf;
        size_t count;
-       off_t off;
 };
 
 struct write_call {
@@ -85,6 +87,10 @@ struct write_call {
        const void *buf;
        size_t count;
        off_t off;
+       off_t old_filelen;
+       off_t saved_len;
+       void *saved_contents;
+       int dup_fd;
 };
 
 struct fcntl_call {
@@ -121,6 +127,8 @@ struct failtest_call {
        bool fail;
        /* What we set errno to. */
        int error;
+       /* How do we clean this up? */
+       void (*cleanup)(void *u);
        /* The actual call data. */
        union {
                struct calloc_call calloc;
index 236441fcfc78e74c6dd632308d5bed7eaf4f5223..d5be2829d5e0dd418ae35eb4dd7b2f26543cccf7 100644 (file)
 #define realloc(ptr, size)                                     \
        failtest_realloc((ptr), (size), __FILE__, __LINE__)
 
+#undef free
+#define free(ptr) \
+       failtest_free(ptr)
+
 /* Replacement of I/O. */
 #include <sys/types.h>
 #include <sys/stat.h>
index 89e1e1b6fd9e6c67d0ecca3cfac72f6f75992ef3..58337301ee223858ba903210ef586cd4c505c832 100644 (file)
@@ -8,6 +8,7 @@ void *failtest_calloc(size_t nmemb, size_t size,
 void *failtest_malloc(size_t size, const char *file, unsigned line);
 void *failtest_realloc(void *ptr, size_t size,
                       const char *file, unsigned line);
+void failtest_free(void *ptr);
 int failtest_open(const char *pathname,
                  const char *file, unsigned line, ...);
 int failtest_pipe(int pipefd[2], const char *file, unsigned line);
index dc5a3f96a4732f16c6232595f2578ea922a6799d..ef28a3f5a09329db0722bffbc55a0f549f3fed20 100644 (file)
@@ -45,8 +45,8 @@ int main(void)
        realloc_call.ret = realloc(malloc_call.ret, 3);
        realloc_call.ptr = malloc_call.ret;
        realloc_call.size = 3;
-       call = add_history(FAILTEST_REALLOC, "run-history.c",
-                          3, &realloc_call);
+       call = add_history(FAILTEST_REALLOC, "run-history.c", 3,
+                          &realloc_call);
        ok1(call->type == FAILTEST_REALLOC);
        ok1(strcmp(call->file, "run-history.c") == 0);
        ok1(call->line == 3);
index dda7ddb643b75b20a1b27036d8e04c4cbdefc590..3ac93aebb12af7ebec51fedc0e388c8773bcac40 100644 (file)
@@ -41,7 +41,7 @@ int main(void)
        ok1(err == EACCES);
 
        /* Clean up. */
-       close(fd);
+       failtest_close(fd);
        close(pfd[0]);
        close(pfd[1]);
 
@@ -59,7 +59,7 @@ int main(void)
        ok1(read(fd, buf, strlen("Hello world!")) == strlen("Hello world!"));
        ok1(strcmp(buf, "Hello world!") == 0);
        /* Clean up. */
-       close(fd);
+       failtest_close(fd);
        close(pfd[0]);
        close(pfd[1]);