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-rw-r--r--0003-Fix-8051-use-old-way-as-fallback-to-save-configurati.patch96
1 files changed, 96 insertions, 0 deletions
diff --git a/0003-Fix-8051-use-old-way-as-fallback-to-save-configurati.patch b/0003-Fix-8051-use-old-way-as-fallback-to-save-configurati.patch
new file mode 100644
index 0000000..ddc2066
--- /dev/null
+++ b/0003-Fix-8051-use-old-way-as-fallback-to-save-configurati.patch
@@ -0,0 +1,96 @@
+From bd2302cb5ff137e03b056c9643991bd7ce7f0f5e Mon Sep 17 00:00:00 2001
+From: Remi Collet <remi@remirepo.net>
+Date: Mon, 16 Nov 2020 11:04:10 +0100
+Subject: [PATCH] Fix #8051 use old way as fallback to save configuration file
+ in non writable dir
+
+---
+ src/config.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 65 insertions(+)
+
+diff --git a/src/config.c b/src/config.c
+index 07ed91e5f..c93407265 100644
+--- a/src/config.c
++++ b/src/config.c
+@@ -1580,6 +1580,67 @@ void rewriteConfigRemoveOrphaned(struct rewriteConfigState *state) {
+ dictReleaseIterator(di);
+ }
+
++/* This function overwrites the old configuration file with the new content.
++ *
++ * 1) The old file length is obtained.
++ * 2) If the new content is smaller, padding is added.
++ * 3) A single write(2) call is used to replace the content of the file.
++ * 4) Later the file is truncated to the length of the new content.
++ *
++ * This way we are sure the file is left in a consistent state even if the
++ * process is stopped between any of the four operations.
++ *
++ * This fallback method is called when atomic fails because of missing
++ * write permission in the configuration directory (e.g. /etc)
++ *
++ * The function returns 0 on success, otherwise -1 is returned and errno
++ * set accordingly. */
++int rewriteConfigOverwriteFileFallback(char *configfile, sds content) {
++ int retval = 0;
++ int fd = open(configfile,O_RDWR|O_CREAT,0644);
++ int content_size = sdslen(content), padding = 0;
++ struct stat sb;
++ sds content_padded;
++
++ /* 1) Open the old file (or create a new one if it does not
++ * exist), get the size. */
++ if (fd == -1) return -1; /* errno set by open(). */
++ if (fstat(fd,&sb) == -1) {
++ close(fd);
++ return -1; /* errno set by fstat(). */
++ }
++
++ /* 2) Pad the content at least match the old file size. */
++ content_padded = sdsdup(content);
++ if (content_size < sb.st_size) {
++ /* If the old file was bigger, pad the content with
++ * a newline plus as many "#" chars as required. */
++ padding = sb.st_size - content_size;
++ content_padded = sdsgrowzero(content_padded,sb.st_size);
++ content_padded[content_size] = '\n';
++ memset(content_padded+content_size+1,'#',padding-1);
++ }
++
++ /* 3) Write the new content using a single write(2). */
++ if (write(fd,content_padded,strlen(content_padded)) == -1) {
++ retval = -1;
++ goto cleanup;
++ }
++
++ /* 4) Truncate the file to the right length if we used padding. */
++ if (padding) {
++ if (ftruncate(fd,content_size) == -1) {
++ /* Non critical error... */
++ }
++ }
++ serverLog(LL_DEBUG, "Rewritten config file (%s) successfully", configfile);
++
++cleanup:
++ sdsfree(content_padded);
++ close(fd);
++ return retval;
++}
++
+ /* This function replaces the old configuration file with the new content
+ * in an atomic manner.
+ *
+@@ -1608,6 +1669,10 @@ int rewriteConfigOverwriteFile(char *configfile, sds content) {
+ #endif
+
+ if (fd == -1) {
++ if (errno == EACCES) {
++ serverLog(LL_DEBUG, "Could not create tmp config file (%s), try fallback", strerror(errno));
++ return rewriteConfigOverwriteFileFallback(configfile, content);
++ }
+ serverLog(LL_WARNING, "Could not create tmp config file (%s)", strerror(errno));
+ return retval;
+ }
+--
+2.25.4
+