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util: unify getenv() logic for other PID

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This commit is contained in:
Lennart Poettering 2012-04-22 14:48:46 +02:00
parent 144f0fc0c8
commit ab94af9201
4 changed files with 97 additions and 89 deletions
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45
src/core/machine-id-setup.c
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@ -110,45 +110,22 @@ static int generate(char id[34]) {
/* If that didn't work either, see if we are running in a
* container, and a machine ID was passed in via
* $container_uuid the way libvirt/LXC does it */
r = detect_container(NULL);
if (r > 0) {
FILE *f;
char *e;
f = fopen("/proc/1/environ", "re");
if (f) {
bool done = false;
do {
char line[LINE_MAX];
unsigned i;
for (i = 0; i < sizeof(line)-1; i++) {
int c;
c = getc(f);
if (_unlikely_(c == EOF)) {
done = true;
break;
} else if (c == 0)
break;
line[i] = c;
r = getenv_for_pid(1, "container_uuid", &e);
if (r > 0) {
if (strlen(e) >= 36) {
r = shorten_uuid(id, e);
if (r >= 0) {
log_info("Initializing machine ID from container UUID");
free(e);
return 0;
}
line[i] = 0;
}
if (startswith(line, "container_uuid=") &&
strlen(line + 15) >= 36) {
r = shorten_uuid(id, line + 15);
if (r >= 0) {
log_info("Initializing machine ID from container UUID");
return 0;
}
}
} while (!done);
fclose(f);
free(e);
}
}

62
src/shared/util.c
View File

@ -6168,3 +6168,65 @@ int path_is_read_only_fs(const char *path) {
return !!(st.f_flag & ST_RDONLY);
}
int getenv_for_pid(pid_t pid, const char *field, char **_value) {
char path[sizeof("/proc/")-1+10+sizeof("/environ")], *value = NULL;
int r;
FILE *f;
bool done = false;
size_t l;
assert(field);
assert(_value);
if (pid == 0)
pid = getpid();
snprintf(path, sizeof(path), "/proc/%lu/environ", (unsigned long) pid);
char_array_0(path);
f = fopen(path, "re");
if (!f)
return -errno;
l = strlen(field);
r = 0;
do {
char line[LINE_MAX];
unsigned i;
for (i = 0; i < sizeof(line)-1; i++) {
int c;
c = getc(f);
if (_unlikely_(c == EOF)) {
done = true;
break;
} else if (c == 0)
break;
line[i] = c;
}
line[i] = 0;
if (memcmp(line, field, l) == 0 && line[l] == '=') {
value = strdup(line + l + 1);
if (!value) {
r = -ENOMEM;
break;
}
r = 1;
break;
}
} while (!done);
fclose(f);
if (r >= 0)
*_value = value;
return r;
}

2
src/shared/util.h
View File

@ -540,4 +540,6 @@ int fork_agent(pid_t *pid, const int except[], unsigned n_except, const char *pa
int setrlimit_closest(int resource, const struct rlimit *rlim);
int getenv_for_pid(pid_t pid, const char *field, char **_value);
#endif

77
src/shared/virt.c
View File

@ -153,7 +153,8 @@ int detect_vm(const char **id) {
}
int detect_container(const char **id) {
FILE *f;
char *e = NULL;
int r;
/* Unfortunately many of these operations require root access
* in one way or another */
@ -180,63 +181,29 @@ int detect_container(const char **id) {
return 1;
}
f = fopen("/proc/1/environ", "re");
if (f) {
bool done = false;
r = getenv_for_pid(1, "container", &e);
if (r <= 0)
return r;
do {
char line[LINE_MAX];
unsigned i;
for (i = 0; i < sizeof(line)-1; i++) {
int c;
c = getc(f);
if (_unlikely_(c == EOF)) {
done = true;
break;
} else if (c == 0)
break;
line[i] = c;
}
line[i] = 0;
if (streq(line, "container=lxc")) {
fclose(f);
if (id)
*id = "lxc";
return 1;
} else if (streq(line, "container=lxc-libvirt")) {
fclose(f);
if (id)
*id = "lxc-libvirt";
return 1;
} else if (streq(line, "container=systemd-nspawn")) {
fclose(f);
if (id)
*id = "systemd-nspawn";
return 1;
} else if (startswith(line, "container=")) {
fclose(f);
if (id)
*id = "other";
return 1;
}
} while (!done);
fclose(f);
/* We only recognize a selected few here, since we want to
* enforce a redacted namespace */
if (streq(e, "lxc")) {
if (id)
*id = "lxc";
} else if (streq(e, "lxc-libvirt")) {
if (id)
*id = "lxc-libvirt";
} else if (streq(e, "systemd-nspawn")) {
if (id)
*id = "systemd-nspawn";
} else {
if (id)
*id = "other";
}
return 0;
free(e);
return r;
}
/* Returns a short identifier for the various VM/container implementations */