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authormidipix <writeonce@midipix.org>2020-04-30 01:26:47 -0400
committermidipix <writeonce@midipix.org>2020-05-23 05:59:02 +0000
commite0fd2a143d1ff76373786ced79c2af7cbcb28025 (patch)
treea1c2c238cf1d5af386cbb568ea61a54bd3183b91
parent845037353c2db876f004f024b5b50cc18cb70a7a (diff)
downloadtpax-e0fd2a143d1ff76373786ced79c2af7cbcb28025.tar.bz2
tpax-e0fd2a143d1ff76373786ced79c2af7cbcb28025.tar.xz
library api: tpax_file_create_memory_snapshot(): initial implementation.
-rw-r--r--include/tpax/tpax.h5
-rw-r--r--project/common.mk1
-rw-r--r--src/logic/tpax_file_create_memory_snapshot.c101
-rw-r--r--src/output/tpax_output_error.c2
4 files changed, 109 insertions, 0 deletions
diff --git a/include/tpax/tpax.h b/include/tpax/tpax.h
index c39f721..8d6183b 100644
--- a/include/tpax/tpax.h
+++ b/include/tpax/tpax.h
@@ -66,6 +66,8 @@ enum tpax_custom_error {
TPAX_ERR_NULL_CONTEXT,
TPAX_ERR_BAD_DATA,
TPAX_ERR_FORBIDDEN_PATH,
+ TPAX_ERR_FILE_CHANGED,
+ TPAX_ERR_REGION_SIZE,
TPAX_ERR_CAP,
};
@@ -161,6 +163,9 @@ tpax_api int tpax_output_error_vector (const struct tpax_driver_ctx *);
tpax_api int tpax_init_ustar_header (const struct tpax_driver_ctx *, const char *, const struct stat *,
const char *, struct tpax_ustar_header *);
+tpax_api int tpax_file_create_memory_snapshot (const struct tpax_driver_ctx *, const char *,
+ const struct stat *, void *);
+
/* package info */
tpax_api const struct tpax_source_version * tpax_source_version(void);
diff --git a/project/common.mk b/project/common.mk
index 14d6ec8..da9fa26 100644
--- a/project/common.mk
+++ b/project/common.mk
@@ -5,6 +5,7 @@ API_SRCS = \
src/helper/tpax_path_copy.c \
src/helper/tpax_stat_compare.c \
src/logic/tpax_init_ustar_header.c \
+ src/logic/tpax_file_create_memory_snapshot.c \
src/output/tpax_output_error.c \
src/skin/tpax_skin_default.c \
diff --git a/src/logic/tpax_file_create_memory_snapshot.c b/src/logic/tpax_file_create_memory_snapshot.c
new file mode 100644
index 0000000..7db21ea
--- /dev/null
+++ b/src/logic/tpax_file_create_memory_snapshot.c
@@ -0,0 +1,101 @@
+/******************************************************/
+/* tpax: a topological pax implementation */
+/* Copyright (C) 2020 Z. Gilboa */
+/* Released under GPLv2 and GPLv3; see COPYING.TPAX. */
+/******************************************************/
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <grp.h>
+#include <pwd.h>
+#include <sys/stat.h>
+
+#include <tpax/tpax.h>
+#include <tpax/tpax_specs.h>
+#include "tpax_driver_impl.h"
+#include "tpax_errinfo_impl.h"
+
+#ifndef ssizeof
+#define ssizeof(x) (ssize_t)(sizeof(x))
+#endif
+
+int tpax_file_create_memory_snapshot(
+ const struct tpax_driver_ctx * dctx,
+ const char * path,
+ const struct stat * srcst,
+ void * addr)
+{
+ int fd;
+ char * ch;
+ char * cap;
+ ssize_t nread;
+ struct stat dstst;
+
+ /* record errors */
+ tpax_driver_set_ectx(
+ dctx,0,path);
+
+ /* memory snapshot internal limit */
+ if (srcst->st_size >= 0x80000000)
+ return TPAX_CUSTOM_ERROR(dctx,TPAX_ERR_REGION_SIZE);
+
+ /* open */
+ fd = openat(
+ tpax_driver_fdcwd(dctx),path,
+ O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
+
+ if (fd < 0)
+ return TPAX_SYSTEM_ERROR(dctx);
+
+ /* stat compare */
+ if ((fstat(fd,&dstst)) < 0) {
+ close(fd);
+ return TPAX_SYSTEM_ERROR(dctx);
+
+ } else if (tpax_stat_compare(srcst,&dstst)) {
+ close(fd);
+ return TPAX_CUSTOM_ERROR(dctx,TPAX_ERR_FILE_CHANGED);
+ }
+
+ /* read loop */
+ ch = addr;
+ cap = &ch[srcst->st_size];
+
+ while (ch < cap) {
+ nread = read(fd,ch,cap-ch);
+
+ while ((nread < 0) && (errno == EINTR))
+ nread = read(fd,ch,cap-ch);
+
+ if (nread < 0) {
+ close(fd);
+ return TPAX_SYSTEM_ERROR(dctx);
+
+ } else if (nread == 0) {
+ close(fd);
+ return TPAX_CUSTOM_ERROR(dctx,TPAX_ERR_FLOW_ERROR);
+
+ } else {
+ ch += nread;
+ }
+ }
+
+ /* stat compare */
+ if ((fstat(fd,&dstst)) < 0) {
+ close(fd);
+ return TPAX_SYSTEM_ERROR(dctx);
+
+ } else if (tpax_stat_compare(srcst,&dstst)) {
+ close(fd);
+ return TPAX_CUSTOM_ERROR(dctx,TPAX_ERR_FILE_CHANGED);
+ }
+
+ /* yay */
+ close(fd);
+
+ return 0;
+}
diff --git a/src/output/tpax_output_error.c b/src/output/tpax_output_error.c
index 69c4938..de09f21 100644
--- a/src/output/tpax_output_error.c
+++ b/src/output/tpax_output_error.c
@@ -26,6 +26,8 @@ static const char * const tpax_error_strings[TPAX_ERR_CAP] = {
[TPAX_ERR_FLEE_ERROR] = "flees and bugs and cats and mice",
[TPAX_ERR_NULL_CONTEXT] = "null driver or unit context",
[TPAX_ERR_BAD_DATA] = "corrupt or wrong daata",
+ [TPAX_ERR_FILE_CHANGED] = "file has changed",
+ [TPAX_ERR_REGION_SIZE] = "file too large for a memory snapshot",
};
static const char * tpax_output_error_header(const struct tpax_error_info * erri)