From afe0c36d832df68c19373b2a99abba4fc840f0e1 Mon Sep 17 00:00:00 2001

From: Martin Kutlak <mkutlak@redhat.com>

Date: Tue, 21 May 2019 10:42:53 +0200

Subject: [PATCH] lib: add get env variable from a file

Introduced a new argument called 'delim' because /proc/PID/environ is

delimited with 0 but FILENAME_ENVIRON is escaped version of that file

with '\0's replaced by '\n'.

While /proc/PID/environ entries are always delimted by '\0' (even the

last one), other files might not use this style and the function must

handle EOF without the entry delimiter.

Cherry-picked from https://github.com/abrt/libreport/commit/a71e4149c85212c72af0cc67c5b99a5029491ed2

---

 src/include/internal_libreport.h |  2 ++

 src/lib/get_cmdline.c            | 38 ++++++++++++++++++++++++++------

 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/src/include/internal_libreport.h b/src/include/internal_libreport.h

index d7bab4e..fc0242c 100644

--- a/src/include/internal_libreport.h

+++ b/src/include/internal_libreport.h

@@ -638,6 +638,8 @@ struct strbuf *strbuf_prepend_strfv(struct strbuf *strbuf,

 char* get_cmdline(pid_t pid);

 #define get_environ libreport_get_environ

 char* get_environ(pid_t pid);

+#define get_env_variable_ext libreport_get_env_variable_ext

+int get_env_variable_ext(int fd, char delim, const char *name, char **value);

 #define get_env_variable libreport_get_env_variable

 int get_env_variable(pid_t pid, const char *name, char **value);

diff --git a/src/lib/get_cmdline.c b/src/lib/get_cmdline.c

index 0fc0cbf..9e83994 100644

--- a/src/lib/get_cmdline.c

+++ b/src/lib/get_cmdline.c

@@ -149,15 +149,20 @@ char* get_environ(pid_t pid)

     return get_escaped(path, '\n');

 }

-int get_env_variable(pid_t pid, const char *name, char **value)

+int get_env_variable_ext(int fd, char delim, const char *name, char **value)

 {

-    char path[sizeof("/proc/%lu/environ") + sizeof(long)*3];

-    snprintf(path, sizeof(path), "/proc/%lu/environ", (long)pid);

+    int workfd = dup(fd);

+    if (workfd < 0)

+    {

+        perror_msg("dup()");

+        return -errno;

+    }

-    FILE *fenv = fopen(path, "re");

+    FILE *fenv = fdopen(workfd, "re");

     if (fenv == NULL)

     {

-        pwarn_msg("Failed to open environ file");

+        close(workfd);

+        perror_msg("fdopen()");

         return -errno;

     }

@@ -177,17 +182,18 @@ int get_env_variable(pid_t pid, const char *name, char **value)

         i = 0;

         /* Read to the end of variable entry */

-        while ((c = fgetc(fenv)) != EOF && c !='\0')

+        while ((c = fgetc(fenv)) != EOF && c != delim)

             ++i;

         /* Go to the next entry if the read entry isn't the searched variable */

         if (skip)

             continue;

+        const int eof = c != EOF;

         *value = xmalloc(i+1);

         /* i+1 because we didn't count '\0'  */

-        if (fseek(fenv, -(i+1), SEEK_CUR) < 0)

+        if (fseek(fenv, -(i+eof), SEEK_CUR) < 0)

             error_msg_and_die("Failed to seek");

         if (fread(*value, 1, i, fenv) != i)

@@ -201,3 +207,21 @@ int get_env_variable(pid_t pid, const char *name, char **value)

     fclose(fenv);

     return 0;

 }

+

+int get_env_variable(pid_t pid, const char *name, char **value)

+{

+    char path[sizeof("/proc/%lu/environ") + sizeof(long)*3];

+    snprintf(path, sizeof(path), "/proc/%lu/environ", (long)pid);

+

+    const int envfd = open(path, O_RDONLY);

+    if (envfd < 0)

+    {

+        pwarn_msg("Failed to open environ file");

+        return -errno;

+    }

+

+    const int r = get_env_variable_ext(envfd, '\0', name, value);

+    close(envfd);

+

+    return r;

+}

-- 

2.21.0