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authorMarkus F.X.J. Oberhumer <markus@oberhumer.com>2021-04-15 18:37:32 +0200
committerMarkus F.X.J. Oberhumer <markus@oberhumer.com>2021-04-15 18:37:32 +0200
commit3dad2125b9048fdc3790d3e7c4770f7174be889c (patch)
tree25a723baf00892f61d103029a983fec6b60bf550
parent68622a02adfa7ebd3a195667d3fbf8e1f10ca93f (diff)
downloadbfs-3dad2125b9048fdc3790d3e7c4770f7174be889c.tar.xz
util: add safe_read_all() and safe_write_all() functions.
-rw-r--r--bar.c12
-rw-r--r--spawn.c4
-rw-r--r--util.c35
-rw-r--r--util.h10
4 files changed, 48 insertions, 13 deletions
diff --git a/bar.c b/bar.c
index 67f5d6e..33127f8 100644
--- a/bar.c
+++ b/bar.c
@@ -58,17 +58,7 @@ static int bfs_bar_getsize(struct bfs_bar *bar) {
/** Async Signal Safe puts(). */
static int ass_puts(int fd, const char *str) {
size_t len = strlen(str);
-
- while (len > 0) {
- ssize_t ret = safe_write(fd, str, len);
- if (ret <= 0) {
- return -1;
- }
- str += ret;
- len -= ret;
- }
-
- return 0;
+ return safe_write_all(fd, str, len) == (ssize_t)len ? 0 : -1;
}
/** Number of decimal digits needed for terminal sizes. */
diff --git a/spawn.c b/spawn.c
index 5878122..0a260dc 100644
--- a/spawn.c
+++ b/spawn.c
@@ -191,7 +191,7 @@ fail:
// In case of write error parent will still see that we exited
// unsuccessfully, but won't know why.
- safe_write(pipefd[1], &error, sizeof(error));
+ (void) safe_write_all(pipefd[1], &error, sizeof(error));
close(pipefd[1]);
_Exit(127);
@@ -221,7 +221,7 @@ pid_t bfs_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char
// Parent
close(pipefd[1]);
- ssize_t nbytes = safe_read(pipefd[0], &error, sizeof(error));
+ ssize_t nbytes = safe_read_all(pipefd[0], &error, sizeof(error));
close(pipefd[0]);
if (nbytes == sizeof(error)) {
int wstatus;
diff --git a/util.c b/util.c
index 611d4b5..00f5b78 100644
--- a/util.c
+++ b/util.c
@@ -379,6 +379,23 @@ ssize_t safe_read(int fd, void *buf, size_t nbytes) {
}
}
+ssize_t safe_read_all(int fd, void *buf, size_t nbytes) {
+ size_t count = 0;
+ for (;;) {
+ ssize_t ret = read(fd, (char *)buf + count, nbytes - count);
+ if (ret < 0 && errno == EINTR) {
+ continue;
+ }
+ if (ret < 0) {
+ return ret; // always return error < 0
+ }
+ count += ret;
+ if (ret == 0 || count == nbytes) { // EOF or success
+ return count;
+ }
+ }
+}
+
ssize_t safe_write(int fd, const void *buf, size_t nbytes) {
for (;;) {
ssize_t ret = write(fd, buf, nbytes);
@@ -388,3 +405,21 @@ ssize_t safe_write(int fd, const void *buf, size_t nbytes) {
return ret;
}
}
+
+ssize_t safe_write_all(int fd, const void *buf, size_t nbytes)
+{
+ size_t count = 0;
+ for (;;) {
+ ssize_t ret = write(fd, (const char *)buf + count, nbytes - count);
+ if (ret < 0 && errno == EINTR) {
+ continue;
+ }
+ if (ret < 0) {
+ return ret; // always return error < 0
+ }
+ count += ret;
+ if (ret == 0 || count == nbytes) { // EOF (should never happen with write) or success
+ return count;
+ }
+ }
+}
diff --git a/util.h b/util.h
index ef67566..7293d50 100644
--- a/util.h
+++ b/util.h
@@ -231,8 +231,18 @@ int bfs_minor(dev_t dev);
ssize_t safe_read(int fd, void *buf, size_t nbytes);
/**
+ * A safe version of read() that handles interrupted system calls and partial reads.
+ */
+ssize_t safe_read_all(int fd, void *buf, size_t nbytes);
+
+/**
* A safe version of write() that handles interrupted system calls.
*/
ssize_t safe_write(int fd, const void *buf, size_t nbytes);
+/**
+ * A safe version of write() that handles interrupted system calls and partial writes.
+ */
+ssize_t safe_write_all(int fd, const void *buf, size_t nbytes);
+
#endif // BFS_UTIL_H