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=== Description (from pull-request) ===
The ELF binary spec doesn specify:
SHT_INIT_ARRAY
This section contains an array of pointers to initialization functions,
as described in ``Initialization and Termination Functions'' in Chapter
5. Each pointer in the array is taken as a parameterless procedure with
a void return.
which means libcs other than glibc might not pass down argc and argv to
constructors.
This reverts commit 2149bdaf895a1145d49e7627b50e0097678de189.
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
From 4f4b5c57c3d4bd75bde3035e3c8f3ece7b71b7d1 Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brau...@ubuntu.com>
Date: Thu, 14 Feb 2019 14:35:10 +0100
Subject: [PATCH] Revert "lxd: remove /proc/self/cmdline parsing"
The ELF binary spec doesn specify:
SHT_INIT_ARRAY
This section contains an array of pointers to initialization functions,
as described in ``Initialization and Termination Functions'' in Chapter
5. Each pointer in the array is taken as a parameterless procedure with
a void return.
which means libcs other than glibc might not pass down argc and argv to
constructors.
This reverts commit 2149bdaf895a1145d49e7627b50e0097678de189.
Signed-off-by: Christian Brauner <christian.brau...@ubuntu.com>
---
lxd/main_forkfile.go | 4 ----
lxd/main_nsexec.go | 54 ++++++++++++++++++++++++++++++++------------
2 files changed, 39 insertions(+), 19 deletions(-)
diff --git a/lxd/main_forkfile.go b/lxd/main_forkfile.go
index 24576da18b..38030e2ae0 100644
--- a/lxd/main_forkfile.go
+++ b/lxd/main_forkfile.go
@@ -409,10 +409,6 @@ void forkfile() {
// Get the subcommand
command = advance_arg(false);
- if (command)
- fprintf(stderr, "BBBB: %s\n", command);
- else
- fprintf(stderr, "CCCC\n");
if (command == NULL || (strcmp(command, "--help") == 0 ||
strcmp(command, "--version") == 0 || strcmp(command, "-h") == 0)) {
return;
}
diff --git a/lxd/main_nsexec.go b/lxd/main_nsexec.go
index 789ad7b914..c03a5d24f0 100644
--- a/lxd/main_nsexec.go
+++ b/lxd/main_nsexec.go
@@ -42,12 +42,17 @@ extern void forkproxy();
extern void forkuevent();
// Command line parsing and tracking
-#define CMDLINE_INDEX_SKIP_SELF 1
-size_t cmdline_index = CMDLINE_INDEX_SKIP_SELF;
-char **cmdline;
+#define CMDLINE_SIZE (8 * PATH_MAX)
+char cmdline_buf[CMDLINE_SIZE];
+char *cmdline_cur = NULL;
+ssize_t cmdline_size = -1;
char* advance_arg(bool required) {
- if (!cmdline[cmdline_index]) {
+ while (*cmdline_cur != 0)
+ cmdline_cur++;
+
+ cmdline_cur++;
+ if (cmdline_size <= cmdline_cur - cmdline_buf) {
if (!required)
return NULL;
@@ -55,7 +60,7 @@ char* advance_arg(bool required) {
_exit(1);
}
- return cmdline[cmdline_index++];
+ return cmdline_cur;
}
void error(char *msg)
@@ -205,27 +210,46 @@ void attach_userns(int pid) {
}
}
-__attribute__((constructor)) void init(int argc, char *argv[]) {
- cmdline = argv;
+__attribute__((constructor)) void init(void) {
+ int cmdline;
+
+ // Extract arguments
+ cmdline = open("/proc/self/cmdline", O_RDONLY);
+ if (cmdline < 0) {
+ error("error: open");
+ _exit(232);
+ }
- char *cmd = advance_arg(false);
- if (!cmd) {
+ memset(cmdline_buf, 0, sizeof(cmdline_buf));
+ if ((cmdline_size = read(cmdline, cmdline_buf, sizeof(cmdline_buf)-1))
< 0) {
+ close(cmdline);
+ error("error: read");
+ _exit(232);
+ }
+ close(cmdline);
+
+ // Skip the first argument (but don't fail on missing second argument)
+ cmdline_cur = cmdline_buf;
+ while (*cmdline_cur != 0)
+ cmdline_cur++;
+ cmdline_cur++;
+ if (cmdline_size <= cmdline_cur - cmdline_buf) {
checkfeature();
return;
}
// Intercepts some subcommands
- if (strcmp(cmd, "forkfile") == 0)
+ if (strcmp(cmdline_cur, "forkfile") == 0)
forkfile();
- else if (strcmp(cmd, "forkmount") == 0)
+ else if (strcmp(cmdline_cur, "forkmount") == 0)
forkmount();
- else if (strcmp(cmd, "forknet") == 0)
+ else if (strcmp(cmdline_cur, "forknet") == 0)
forknet();
- else if (strcmp(cmd, "forkproxy") == 0)
+ else if (strcmp(cmdline_cur, "forkproxy") == 0)
forkproxy();
- else if (strcmp(cmd, "forkuevent") == 0)
+ else if (strcmp(cmdline_cur, "forkuevent") == 0)
forkuevent();
- else if (strncmp(cmd, "-", 1) == 0 || strcmp(cmdline[1], "daemon") == 0)
+ else if (strncmp(cmdline_cur, "-", 1) == 0 || strcmp(cmdline_cur,
"daemon") == 0)
checkfeature();
}
*/
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